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Author SHA1 Message Date
David Hildenbrand
5ca432896a mm/rmap: move SetPageAnonExclusive() out of page_move_anon_rmap() 
Patch series "mm/rmap: convert page_move_anon_rmap() to
folio_move_anon_rmap()".

Convert page_move_anon_rmap() to folio_move_anon_rmap(), letting the
callers handle PageAnonExclusive.  I'm including cleanup patch #3 because
it fits into the picture and can be done cleaner by the conversion.


This patch (of 3):

Let's move it into the caller: there is a difference between whether an
anon folio can only be mapped by one process (e.g., into one VMA), and
whether it is truly exclusive (e.g., no references -- including GUP --
from other processes).

Further, for large folios the page might not actually be pointing at the
head page of the folio, so it better be handled in the caller.  This is a
preparation for converting page_move_anon_rmap() to consume a folio.

Link: https://lkml.kernel.org/r/20231002142949.235104-1-david@redhat.com
Link: https://lkml.kernel.org/r/20231002142949.235104-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
4a68fef16d mm: handle write faults to RO pages under the VMA lock 
I think this is a pretty rare occurrence, but for consistency handle
faults with the VMA lock held the same way that we handle other faults
with the VMA lock held.

Link: https://lkml.kernel.org/r/20231006195318.4087158-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
12214eba19 mm: handle read faults under the VMA lock 
Most file-backed faults are already handled through ->map_pages(), but if
we need to do I/O we'll come this way.  Since filemap_fault() is now safe
to be called under the VMA lock, we can handle these faults under the VMA
lock now.

Link: https://lkml.kernel.org/r/20231006195318.4087158-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
4de8c93a47 mm: handle COW faults under the VMA lock 
If the page is not currently present in the page tables, we need to call
the page fault handler to find out which page we're supposed to COW, so we
need to both check that there is already an anon_vma and that the fault
handler doesn't need the mmap_lock.

Link: https://lkml.kernel.org/r/20231006195318.4087158-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
4ed4379881 mm: handle shared faults under the VMA lock 
There are many implementations of ->fault and some of them depend on
mmap_lock being held.  All vm_ops that implement ->map_pages() end up
calling filemap_fault(), which I have audited to be sure it does not rely
on mmap_lock.  So (for now) key off ->map_pages existing as a flag to
indicate that it's safe to call ->fault while only holding the vma lock.

Link: https://lkml.kernel.org/r/20231006195318.4087158-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
164b06f238 mm: call wp_page_copy() under the VMA lock 
It is usually safe to call wp_page_copy() under the VMA lock.  The only
unsafe situation is when no anon_vma has been allocated for this VMA, and
we have to look at adjacent VMAs to determine if their anon_vma can be
shared.  Since this happens only for the first COW of a page in this VMA,
the majority of calls to wp_page_copy() do not need to fall back to the
mmap_sem.

Add vmf_anon_prepare() as an alternative to anon_vma_prepare() which will
return RETRY if we currently hold the VMA lock and need to allocate an
anon_vma.  This lets us drop the check in do_wp_page().

Link: https://lkml.kernel.org/r/20231006195318.4087158-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Matthew Wilcox (Oracle)
5d74b2ab2c mm: make lock_folio_maybe_drop_mmap() VMA lock aware 
Patch series "Handle more faults under the VMA lock", v2.

At this point, we're handling the majority of file-backed page faults
under the VMA lock, using the ->map_pages entry point.  This patch set
attempts to expand that for the following siutations:

 - We have to do a read.  This could be because we've hit the point in
   the readahead window where we need to kick off the next readahead,
   or because the page is simply not present in cache.
 - We're handling a write fault.  Most applications don't do I/O by writes
   to shared mmaps for very good reasons, but some do, and it'd be nice
   to not make that slow unnecessarily.
 - We're doing a COW of a private mapping (both PTE already present
   and PTE not-present).  These are two different codepaths and I handle
   both of them in this patch set.

There is no support in this patch set for drivers to mark themselves as
being VMA lock friendly; they could implement the ->map_pages
vm_operation, but if they do, they would be the first.  This is probably
something we want to change at some point in the future, and I've marked
where to make that change in the code.

There is very little performance change in the benchmarks we've run;
mostly because the vast majority of page faults are handled through the
other paths.  I still think this patch series is useful for workloads that
may take these paths more often, and just for cleaning up the fault path
in general (it's now clearer why we have to retry in these cases).


This patch (of 6):

Drop the VMA lock instead of the mmap_lock if that's the one which
is held.

Link: https://lkml.kernel.org/r/20231006195318.4087158-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231006195318.4087158-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Hugh Dickins
beb9868628 shmem,percpu_counter: add _limited_add(fbc, limit, amount) 
Percpu counter's compare and add are separate functions: without locking
around them (which would defeat their purpose), it has been possible to
overflow the intended limit.  Imagine all the other CPUs fallocating tmpfs
huge pages to the limit, in between this CPU's compare and its add.

I have not seen reports of that happening; but tmpfs's recent addition of
dquot_alloc_block_nodirty() in between the compare and the add makes it
even more likely, and I'd be uncomfortable to leave it unfixed.

Introduce percpu_counter_limited_add(fbc, limit, amount) to prevent it.

I believe this implementation is correct, and slightly more efficient than
the combination of compare and add (taking the lock once rather than twice
when nearing full - the last 128MiB of a tmpfs volume on a machine with
128 CPUs and 4KiB pages); but it does beg for a better design - when
nearing full, there is no new batching, but the costly percpu counter sum
across CPUs still has to be done, while locked.

Follow __percpu_counter_sum()'s example, including cpu_dying_mask as well
as cpu_online_mask: but shouldn't __percpu_counter_compare() and
__percpu_counter_limited_add() then be adding a num_dying_cpus() to
num_online_cpus(), when they calculate the maximum which could be held
across CPUs?  But the times when it matters would be vanishingly rare.

Link: https://lkml.kernel.org/r/bb817848-2d19-bcc8-39ca-ea179af0f0b4@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:14 -07:00
Hugh Dickins
3022fd7af9 shmem: _add_to_page_cache() before shmem_inode_acct_blocks() 
There has been a recurring problem, that when a tmpfs volume is being
filled by racing threads, some fail with ENOSPC (or consequent SIGBUS or
EFAULT) even though all allocations were within the permitted size.

This was a problem since early days, but magnified and complicated by the
addition of huge pages.  We have often worked around it by adding some
slop to the tmpfs size, but it's hard to say how much is needed, and some
users prefer not to do that e.g.  keeping sparse files in a tightly
tailored tmpfs helps to prevent accidental writing to holes.

This comes from the allocation sequence:
1. check page cache for existing folio
2. check and reserve from vm_enough_memory
3. check and account from size of tmpfs
4. if huge, check page cache for overlapping folio
5. allocate physical folio, huge or small
6. check and charge from mem cgroup limit
7. add to page cache (but maybe another folio already got in).

Concurrent tasks allocating at the same position could deplete the size
allowance and fail.  Doing vm_enough_memory and size checks before the
folio allocation was intentional (to limit the load on the page allocator
from this source) and still has some virtue; but memory cgroup never did
that, so I think it's better reordered to favour predictable behaviour.

1. check page cache for existing folio
2. if huge, check page cache for overlapping folio
3. allocate physical folio, huge or small
4. check and charge from mem cgroup limit
5. add to page cache (but maybe another folio already got in)
6. check and reserve from vm_enough_memory
7. check and account from size of tmpfs.

The folio lock held from allocation onwards ensures that the !uptodate
folio cannot be used by others, and can safely be deleted from the cache
if checks 6 or 7 subsequently fail (and those waiting on folio lock
already check that the folio was not truncated once they get the lock);
and the early addition to page cache ensures that racers find it before
they try to duplicate the accounting.

Seize the opportunity to tidy up shmem_get_folio_gfp()'s ENOSPC retrying,
which can be combined inside the new shmem_alloc_and_add_folio(): doing 2
splits twice (once huge, once nonhuge) is not exactly equivalent to trying
5 splits (and giving up early on huge), but let's keep it simple unless
more complication proves necessary.

Userfaultfd is a foreign country: they do things differently there, and
for good reason - to avoid mmap_lock deadlock.  Leave ordering in
shmem_mfill_atomic_pte() untouched for now, but I would rather like to
mesh it better with shmem_get_folio_gfp() in the future.

Link: https://lkml.kernel.org/r/22ddd06-d919-33b-1219-56335c1bf28e@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Hugh Dickins
054a9f7ccd shmem: move memcg charge out of shmem_add_to_page_cache() 
Extract shmem's memcg charging out of shmem_add_to_page_cache(): it's
misleading done there, because many calls are dealing with a swapcache
page, whose memcg is nowadays always remembered while swapped out, then
the charge re-levied when it's brought back into swapcache.

Temporarily move it back up to the shmem_get_folio_gfp() level, where the
memcg was charged before v5.8; but the next commit goes on to move it back
down to a new home.

In making this change, it becomes clear that shmem_swapin_folio() does not
need to know the vma, just the fault mm (if any): call it fault_mm rather
than charge_mm - let mem_cgroup_charge() decide whom to charge.

Link: https://lkml.kernel.org/r/4b2143c5-bf32-64f0-841-81a81158dac@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Hugh Dickins
4199f51a7e shmem: shmem_acct_blocks() and shmem_inode_acct_blocks() 
By historical accident, shmem_acct_block() and shmem_inode_acct_block()
were never pluralized when the pages argument was added, despite their
complements being shmem_unacct_blocks() and shmem_inode_unacct_blocks()
all along.  It has been an irritation: fix their naming at last.

Link: https://lkml.kernel.org/r/9124094-e4ab-8be7-ef80-9a87bdc2e4fc@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Hugh Dickins
9be7d5b066 shmem: trivial tidyups, removing extra blank lines, etc 
Mostly removing a few superfluous blank lines, joining short arglines,
imposing some 80-column observance, correcting a couple of comments.  None
of it more interesting than deleting a repeated INIT_LIST_HEAD().

Link: https://lkml.kernel.org/r/b3983d28-5d3f-8649-36af-b819285d7a9e@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Hugh Dickins
f0a9ad1d4d shmem: factor shmem_falloc_wait() out of shmem_fault() 
That Trinity livelock shmem_falloc avoidance block is unlikely, and a
distraction from the proper business of shmem_fault(): separate it out. 
(This used to help compilers save stack on the fault path too, but both
gcc and clang nowadays seem to make better choices anyway.)

Link: https://lkml.kernel.org/r/6fe379a4-6176-9225-9263-fe60d2633c0@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Hugh Dickins
e3e1a5067f shmem: remove vma arg from shmem_get_folio_gfp() 
The vma is already there in vmf->vma, so no need for a separate arg.

Link: https://lkml.kernel.org/r/d9ce6f65-a2ed-48f4-4299-fdb0544875c5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Lorenzo Stoakes
6facf36ee4 mm/filemap: clarify filemap_fault() comments for not uptodate case 
The existing comments in filemap_fault() suggest that, after either a
minor fault has occurred and filemap_get_folio() found a folio in the page
cache, or a major fault arose and __filemap_get_folio(FGP_CREATE...) did
the job (having relied on do_sync_mmap_readahead() or filemap_read_folio()
to read in the folio), the only possible reason it could not be uptodate
is because of an error.

This is not so, as if, for instance, the fault occurred within a VMA which
had the VM_RAND_READ flag set (via madvise() with the MADV_RANDOM flag
specified), this would cause even synchronous readahead to fail to read in
the folio.

I confirmed this by dropping page caches and faulting in memory
madvise()'d this way, observing that this code path was reached on each
occasion.

Clarify the comments to include this case, and additionally update the
comment recently added around the invalidate lock logic to make it clear
the comment explicitly refers to the minor fault case.

In addition, while we're here, refer to folios rather than pages.

[lstoakes@gmail.com: correct identation as per Christopher's feedback]
  Link: https://lkml.kernel.org/r/2c7014c0-6343-4e76-8697-3f84f54350bd@lucifer.local
Link: https://lkml.kernel.org/r/20230930231029.88196-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:13 -07:00
Muhammad Usama Anjum
52526ca7fd fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs 
The PAGEMAP_SCAN IOCTL on the pagemap file can be used to get or optionally
clear the info about page table entries. The following operations are
supported in this IOCTL:
- Scan the address range and get the memory ranges matching the provided
  criteria. This is performed when the output buffer is specified.
- Write-protect the pages. The PM_SCAN_WP_MATCHING is used to write-protect
  the pages of interest. The PM_SCAN_CHECK_WPASYNC aborts the operation if
  non-Async Write Protected pages are found. The ``PM_SCAN_WP_MATCHING``
  can be used with or without PM_SCAN_CHECK_WPASYNC.
- Both of those operations can be combined into one atomic operation where
  we can get and write protect the pages as well.

Following flags about pages are currently supported:
- PAGE_IS_WPALLOWED - Page has async-write-protection enabled
- PAGE_IS_WRITTEN - Page has been written to from the time it was write protected
- PAGE_IS_FILE - Page is file backed
- PAGE_IS_PRESENT - Page is present in the memory
- PAGE_IS_SWAPPED - Page is in swapped
- PAGE_IS_PFNZERO - Page has zero PFN
- PAGE_IS_HUGE - Page is THP or Hugetlb backed

This IOCTL can be extended to get information about more PTE bits. The
entire address range passed by user [start, end) is scanned until either
the user provided buffer is full or max_pages have been found.

[akpm@linux-foundation.org: update it for "mm: hugetlb: add huge page size param to set_huge_pte_at()"]
[akpm@linux-foundation.org: fix CONFIG_HUGETLB_PAGE=n warning]
[arnd@arndb.de: hide unused pagemap_scan_backout_range() function]
  Link: https://lkml.kernel.org/r/20230927060257.2975412-1-arnd@kernel.org
[sfr@canb.auug.org.au: fix "fs/proc/task_mmu: hide unused pagemap_scan_backout_range() function"]
  Link: https://lkml.kernel.org/r/20230928092223.0625c6bf@canb.auug.org.au
Link: https://lkml.kernel.org/r/20230821141518.870589-3-usama.anjum@collabora.com
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Andrei Vagin <avagin@gmail.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Miroslaw <emmir@google.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yun Zhou <yun.zhou@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:12 -07:00
Peter Xu
d61ea1cb00 userfaultfd: UFFD_FEATURE_WP_ASYNC 
Patch series "Implement IOCTL to get and optionally clear info about
PTEs", v33.

*Motivation*
The real motivation for adding PAGEMAP_SCAN IOCTL is to emulate Windows
GetWriteWatch() and ResetWriteWatch() syscalls [1].  The GetWriteWatch()
retrieves the addresses of the pages that are written to in a region of
virtual memory.

This syscall is used in Windows applications and games etc.  This syscall
is being emulated in pretty slow manner in userspace.  Our purpose is to
enhance the kernel such that we translate it efficiently in a better way. 
Currently some out of tree hack patches are being used to efficiently
emulate it in some kernels.  We intend to replace those with these
patches.  So the whole gaming on Linux can effectively get benefit from
this.  It means there would be tons of users of this code.

CRIU use case [2] was mentioned by Andrei and Danylo:
> Use cases for migrating sparse VMAs are binaries sanitized with ASAN,
> MSAN or TSAN [3]. All of these sanitizers produce sparse mappings of
> shadow memory [4]. Being able to migrate such binaries allows to highly
> reduce the amount of work needed to identify and fix post-migration
> crashes, which happen constantly.

Andrei defines the following uses of this code:
* it is more granular and allows us to track changed pages more
  effectively. The current interface can clear dirty bits for the entire
  process only. In addition, reading info about pages is a separate
  operation. It means we must freeze the process to read information
  about all its pages, reset dirty bits, only then we can start dumping
  pages. The information about pages becomes more and more outdated,
  while we are processing pages. The new interface solves both these
  downsides. First, it allows us to read pte bits and clear the
  soft-dirty bit atomically. It means that CRIU will not need to freeze
  processes to pre-dump their memory. Second, it clears soft-dirty bits
  for a specified region of memory. It means CRIU will have actual info
  about pages to the moment of dumping them.
* The new interface has to be much faster because basic page filtering
  is happening in the kernel. With the old interface, we have to read
  pagemap for each page.

*Implementation Evolution (Short Summary)*
From the definition of GetWriteWatch(), we feel like kernel's soft-dirty
feature can be used under the hood with some additions like:
* reset soft-dirty flag for only a specific region of memory instead of
clearing the flag for the entire process
* get and clear soft-dirty flag for a specific region atomically

So we decided to use ioctl on pagemap file to read or/and reset soft-dirty
flag. But using soft-dirty flag, sometimes we get extra pages which weren't
even written. They had become soft-dirty because of VMA merging and
VM_SOFTDIRTY flag. This breaks the definition of GetWriteWatch(). We were
able to by-pass this short coming by ignoring VM_SOFTDIRTY until David
reported that mprotect etc messes up the soft-dirty flag while ignoring
VM_SOFTDIRTY [5]. This wasn't happening until [6] got introduced. We
discussed if we can revert these patches. But we could not reach to any
conclusion. So at this point, I made couple of tries to solve this whole
VM_SOFTDIRTY issue by correcting the soft-dirty implementation:
* [7] Correct the bug fixed wrongly back in 2014. It had potential to cause
regression. We left it behind.
* [8] Keep a list of soft-dirty part of a VMA across splits and merges. I
got the reply don't increase the size of the VMA by 8 bytes.

At this point, we left soft-dirty considering it is too much delicate and
userfaultfd [9] seemed like the only way forward. From there onward, we
have been basing soft-dirty emulation on userfaultfd wp feature where
kernel resolves the faults itself when WP_ASYNC feature is used. It was
straight forward to add WP_ASYNC feature in userfautlfd. Now we get only
those pages dirty or written-to which are really written in reality. (PS
There is another WP_UNPOPULATED userfautfd feature is required which is
needed to avoid pre-faulting memory before write-protecting [9].)

All the different masks were added on the request of CRIU devs to create
interface more generic and better.

[1] https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-getwritewatch
[2] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com
[3] https://github.com/google/sanitizers
[4] https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#64-bit
[5] https://lore.kernel.org/all/bfcae708-db21-04b4-0bbe-712badd03071@redhat.com
[6] https://lore.kernel.org/all/20220725142048.30450-1-peterx@redhat.com/
[7] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.com
[8] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.com
[9] https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com
[10] https://lore.kernel.org/all/20230125144529.1630917-1-mdanylo@google.com


This patch (of 6):

Add a new userfaultfd-wp feature UFFD_FEATURE_WP_ASYNC, that allows
userfaultfd wr-protect faults to be resolved by the kernel directly.

It can be used like a high accuracy version of soft-dirty, without vma
modifications during tracking, and also with ranged support by default
rather than for a whole mm when reset the protections due to existence of
ioctl(UFFDIO_WRITEPROTECT).

Several goals of such a dirty tracking interface:

1. All types of memory should be supported and tracable. This is nature
   for soft-dirty but should mention when the context is userfaultfd,
   because it used to only support anon/shmem/hugetlb. The problem is for
   a dirty tracking purpose these three types may not be enough, and it's
   legal to track anything e.g. any page cache writes from mmap.

2. Protections can be applied to partial of a memory range, without vma
   split/merge fuss.  The hope is that the tracking itself should not
   affect any vma layout change.  It also helps when reset happens because
   the reset will not need mmap write lock which can block the tracee.

3. Accuracy needs to be maintained.  This means we need pte markers to work
   on any type of VMA.

One could question that, the whole concept of async dirty tracking is not
really close to fundamentally what userfaultfd used to be: it's not "a
fault to be serviced by userspace" anymore. However, using userfaultfd-wp
here as a framework is convenient for us in at least:

1. VM_UFFD_WP vma flag, which has a very good name to suite something like
   this, so we don't need VM_YET_ANOTHER_SOFT_DIRTY. Just use a new
   feature bit to identify from a sync version of uffd-wp registration.

2. PTE markers logic can be leveraged across the whole kernel to maintain
   the uffd-wp bit as long as an arch supports, this also applies to this
   case where uffd-wp bit will be a hint to dirty information and it will
   not go lost easily (e.g. when some page cache ptes got zapped).

3. Reuse ioctl(UFFDIO_WRITEPROTECT) interface for either starting or
   resetting a range of memory, while there's no counterpart in the old
   soft-dirty world, hence if this is wanted in a new design we'll need a
   new interface otherwise.

We can somehow understand that commonality because uffd-wp was
fundamentally a similar idea of write-protecting pages just like
soft-dirty.

This implementation allows WP_ASYNC to imply WP_UNPOPULATED, because so
far WP_ASYNC seems to not usable if without WP_UNPOPULATE.  This also
gives us chance to modify impl of WP_ASYNC just in case it could be not
depending on WP_UNPOPULATED anymore in the future kernels.  It's also fine
to imply that because both features will rely on PTE_MARKER_UFFD_WP config
option, so they'll show up together (or both missing) in an UFFDIO_API
probe.

vma_can_userfault() now allows any VMA if the userfaultfd registration is
only about async uffd-wp.  So we can track dirty for all kinds of memory
including generic file systems (like XFS, EXT4 or BTRFS).

One trick worth mention in do_wp_page() is that we need to manually update
vmf->orig_pte here because it can be used later with a pte_same() check -
this path always has FAULT_FLAG_ORIG_PTE_VALID set in the flags.

The major defect of this approach of dirty tracking is we need to populate
the pgtables when tracking starts.  Soft-dirty doesn't do it like that. 
It's unwanted in the case where the range of memory to track is huge and
unpopulated (e.g., tracking updates on a 10G file with mmap() on top,
without having any page cache installed yet).  One way to improve this is
to allow pte markers exist for larger than PTE level for PMD+.  That will
not change the interface if to implemented, so we can leave that for
later.

Link: https://lkml.kernel.org/r/20230821141518.870589-1-usama.anjum@collabora.com
Link: https://lkml.kernel.org/r/20230821141518.870589-2-usama.anjum@collabora.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Co-developed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Miroslaw <emmir@google.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yun Zhou <yun.zhou@windriver.com>
Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:12 -07:00
Yosry Ahmed
7bd5bc3ce9 mm: memcg: normalize the value passed into memcg_rstat_updated() 
memcg_rstat_updated() uses the value of the state update to keep track of
the magnitude of pending updates, so that we only do a stats flush when
it's worth the work.  Most values passed into memcg_rstat_updated() are in
pages, however, a few of them are actually in bytes or KBs.

To put this into perspective, a 512 byte slab allocation today would look
the same as allocating 512 pages.  This may result in premature flushes,
which means unnecessary work and latency.

Normalize all the state values passed into memcg_rstat_updated() to pages.
Round up non-zero sub-page to 1 page, because memcg_rstat_updated()
ignores 0 page updates.

Link: https://lkml.kernel.org/r/20230922175741.635002-3-yosryahmed@google.com
Fixes: 5b3be698a8 ("memcg: better bounds on the memcg stats updates")
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:12 -07:00
Yosry Ahmed
ff841a06c8 mm: memcg: refactor page state unit helpers 
Patch series "mm: memcg: fix tracking of pending stats updates values", v2.

While working on adjacent code [1], I realized that the values passed into
memcg_rstat_updated() to keep track of the magnitude of pending updates is
consistent.  It is mostly in pages, but sometimes it can be in bytes or
KBs.  Fix that.

Patch 1 reworks memcg_page_state_unit() so that we can reuse it in patch 2
to check and normalize the units of state updates.

[1]https://lore.kernel.org/lkml/20230921081057.3440885-1-yosryahmed@google.com/


This patch (of 2):

memcg_page_state_unit() is currently used to identify the unit of a memcg
state item so that all stats in memory.stat are in bytes.  However, it
lies about the units of WORKINGSET_* stats.  These stats actually
represent pages, but we present them to userspace as a scalar number of
events.  In retrospect, maybe those stats should have been memcg "events"
rather than memcg "state".

In preparation for using memcg_page_state_unit() for other purposes that
need to know the truthful units of different stat items, break it down
into two helpers:
- memcg_page_state_unit() retuns the actual unit of the item.
- memcg_page_state_output_unit() returns the unit used for output.

Use the latter instead of the former in memcg_page_state_output() and
lruvec_page_state_output().  While we are at it, let's show cgroup v1 some
love and add memcg_page_state_local_output() for consistency.

No functional change intended.

Link: https://lkml.kernel.org/r/20230922175741.635002-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20230922175741.635002-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:12 -07:00
Mike Kravetz
30a89adf87 hugetlb: check for hugetlb folio before vmemmap_restore 
In commit d8f5f7e445 ("hugetlb: set hugetlb page flag before
optimizing vmemmap") checks were added to print a warning if
hugetlb_vmemmap_restore was called on a non-hugetlb page.

This was mostly due to ordering issues in the hugetlb page set up and tear
down sequencees.  One place missed was the routine
dissolve_free_huge_page.

Naoya Horiguchi noted: "I saw that VM_WARN_ON_ONCE() in
hugetlb_vmemmap_restore is triggered when memory_failure() is called on a
free hugetlb page with vmemmap optimization disabled (the warning is not
triggered if vmemmap optimization is enabled).  I think that we need check
folio_test_hugetlb() before dissolve_free_huge_page() calls
hugetlb_vmemmap_restore_folio()."

Perform the check as suggested by Naoya.

Link: https://lkml.kernel.org/r/20231017032140.GA3680@monkey
Fixes: d8f5f7e445 ("hugetlb: set hugetlb page flag before optimizing vmemmap")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Tested-by: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 14:34:12 -07:00
Andrew Morton
5ef8f1b2b4 Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-10-18 14:32:58 -07:00
SeongJae Park
76b7069bcc mm/damon/sysfs: check DAMOS regions update progress from before_terminate() 
DAMON_SYSFS can receive DAMOS tried regions update request while kdamond
is already out of the main loop and before_terminate callback
(damon_sysfs_before_terminate() in this case) is not yet called.  And
damon_sysfs_handle_cmd() can further be finished before the callback is
invoked.  Then, damon_sysfs_before_terminate() unlocks damon_sysfs_lock,
which is not locked by anyone.  This happens because the callback function
assumes damon_sysfs_cmd_request_callback() should be called before it. 
Check if the assumption was true before doing the unlock, to avoid this
problem.

Link: https://lkml.kernel.org/r/20231007200432.3110-1-sj@kernel.org
Fixes: f1d13cacab ("mm/damon/sysfs: implement DAMOS tried regions update command")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.2.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Arnd Bergmann
17c17567fe kasan: disable kasan_non_canonical_hook() for HW tags 
On arm64, building with CONFIG_KASAN_HW_TAGS now causes a compile-time
error:

mm/kasan/report.c: In function 'kasan_non_canonical_hook':
mm/kasan/report.c:637:20: error: 'KASAN_SHADOW_OFFSET' undeclared (first use in this function)
  637 |         if (addr < KASAN_SHADOW_OFFSET)
      |                    ^~~~~~~~~~~~~~~~~~~
mm/kasan/report.c:637:20: note: each undeclared identifier is reported only once for each function it appears in
mm/kasan/report.c:640:77: error: expected expression before ';' token
  640 |         orig_addr = (addr - KASAN_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT;

This was caused by removing the dependency on CONFIG_KASAN_INLINE that
used to prevent this from happening. Use the more specific dependency
on KASAN_SW_TAGS || KASAN_GENERIC to only ignore the function for hwasan
mode.

Link: https://lkml.kernel.org/r/20231016200925.984439-1-arnd@kernel.org
Fixes: 12ec6a919b0f ("kasan: print the original fault addr when access invalid shadow")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Haibo Li <haibo.li@mediatek.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Haibo Li
babddbfb7d kasan: print the original fault addr when access invalid shadow 
when the checked address is illegal,the corresponding shadow address from
kasan_mem_to_shadow may have no mapping in mmu table.  Access such shadow
address causes kernel oops.  Here is a sample about oops on arm64(VA
39bit) with KASAN_SW_TAGS and KASAN_OUTLINE on:

[ffffffb80aaaaaaa] pgd=000000005d3ce003, p4d=000000005d3ce003,
    pud=000000005d3ce003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 3 PID: 100 Comm: sh Not tainted 6.6.0-rc1-dirty #43
Hardware name: linux,dummy-virt (DT)
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __hwasan_load8_noabort+0x5c/0x90
lr : do_ib_ob+0xf4/0x110
ffffffb80aaaaaaa is the shadow address for efffff80aaaaaaaa.
The problem is reading invalid shadow in kasan_check_range.

The generic kasan also has similar oops.

It only reports the shadow address which causes oops but not
the original address.

Commit 2f004eea0fc8("x86/kasan: Print original address on #GP")
introduce to kasan_non_canonical_hook but limit it to KASAN_INLINE.

This patch extends it to KASAN_OUTLINE mode.

Link: https://lkml.kernel.org/r/20231009073748.159228-1-haibo.li@mediatek.com
Fixes: 2f004eea0fc8("x86/kasan: Print original address on #GP")
Signed-off-by: Haibo Li <haibo.li@mediatek.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Haibo Li <haibo.li@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Rik van Riel
2820b0f09b hugetlbfs: close race between MADV_DONTNEED and page fault 
Malloc libraries, like jemalloc and tcalloc, take decisions on when to
call madvise independently from the code in the main application.

This sometimes results in the application page faulting on an address,
right after the malloc library has shot down the backing memory with
MADV_DONTNEED.

Usually this is harmless, because we always have some 4kB pages sitting
around to satisfy a page fault.  However, with hugetlbfs systems often
allocate only the exact number of huge pages that the application wants.

Due to TLB batching, hugetlbfs MADV_DONTNEED will free pages outside of
any lock taken on the page fault path, which can open up the following
race condition:

       CPU 1                            CPU 2

       MADV_DONTNEED
       unmap page
       shoot down TLB entry
                                       page fault
                                       fail to allocate a huge page
                                       killed with SIGBUS
       free page

Fix that race by pulling the locking from __unmap_hugepage_final_range
into helper functions called from zap_page_range_single.  This ensures
page faults stay locked out of the MADV_DONTNEED VMA until the huge pages
have actually been freed.

Link: https://lkml.kernel.org/r/20231006040020.3677377-4-riel@surriel.com
Fixes: 04ada095dc ("hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing")
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Rik van Riel
bf4916922c hugetlbfs: extend hugetlb_vma_lock to private VMAs 
Extend the locking scheme used to protect shared hugetlb mappings from
truncate vs page fault races, in order to protect private hugetlb mappings
(with resv_map) against MADV_DONTNEED.

Add a read-write semaphore to the resv_map data structure, and use that
from the hugetlb_vma_(un)lock_* functions, in preparation for closing the
race between MADV_DONTNEED and page faults.

Link: https://lkml.kernel.org/r/20231006040020.3677377-3-riel@surriel.com
Fixes: 04ada095dc ("hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing")
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Rik van Riel
92fe9dcbe4 hugetlbfs: clear resv_map pointer if mmap fails 
Patch series "hugetlbfs: close race between MADV_DONTNEED and page fault", v7.

Malloc libraries, like jemalloc and tcalloc, take decisions on when to
call madvise independently from the code in the main application.

This sometimes results in the application page faulting on an address,
right after the malloc library has shot down the backing memory with
MADV_DONTNEED.

Usually this is harmless, because we always have some 4kB pages sitting
around to satisfy a page fault.  However, with hugetlbfs systems often
allocate only the exact number of huge pages that the application wants.

Due to TLB batching, hugetlbfs MADV_DONTNEED will free pages outside of
any lock taken on the page fault path, which can open up the following
race condition:

       CPU 1                            CPU 2

       MADV_DONTNEED
       unmap page
       shoot down TLB entry
                                       page fault
                                       fail to allocate a huge page
                                       killed with SIGBUS
       free page

Fix that race by extending the hugetlb_vma_lock locking scheme to also
cover private hugetlb mappings (with resv_map), and pulling the locking
from __unmap_hugepage_final_range into helper functions called from
zap_page_range_single.  This ensures page faults stay locked out of the
MADV_DONTNEED VMA until the huge pages have actually been freed.


This patch (of 3):

Hugetlbfs leaves a dangling pointer in the VMA if mmap fails.  This has
not been a problem so far, but other code in this patch series tries to
follow that pointer.

Link: https://lkml.kernel.org/r/20231006040020.3677377-1-riel@surriel.com
Link: https://lkml.kernel.org/r/20231006040020.3677377-2-riel@surriel.com
Fixes: 04ada095dc ("hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:41 -07:00
Johannes Weiner
969d63e1af mm: zswap: fix pool refcount bug around shrink_worker() 
When a zswap store fails due to the limit, it acquires a pool reference
and queues the shrinker.  When the shrinker runs, it drops the reference. 
However, there can be multiple store attempts before the shrinker wakes up
and runs once.  This results in reference leaks and eventual saturation
warnings for the pool refcount.

Fix this by dropping the reference again when the shrinker is already
queued.  This ensures one reference per shrinker run.

Link: https://lkml.kernel.org/r/20231006160024.170748-1-hannes@cmpxchg.org
Fixes: 45190f01dd ("mm/zswap.c: add allocation hysteresis if pool limit is hit")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Chris Mason <clm@fb.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: <stable@vger.kernel.org>	[5.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-18 12:12:40 -07:00
Jeff Layton
cf2766bb7c
mm: convert to new timestamp accessors 
Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-80-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2023-10-18 14:08:30 +02:00
Stefan Roesch
e5a6899126 mm/ksm: add pages_skipped metric 
This change adds the "pages skipped" metric.  To be able to evaluate how
successful smart page scanning is, the pages skipped metric can be
compared to the pages scanned metric.

The pages skipped metric is a cumulative counter.  The counter is stored
under /sys/kernel/mm/ksm/pages_skipped.

Link: https://lkml.kernel.org/r/20230926040939.516161-3-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:39 -07:00
Stefan Roesch
5e924ff54d mm/ksm: add "smart" page scanning mode 
Patch series "Smart scanning mode for KSM", v3.

This patch series adds "smart scanning" for KSM.

What is smart scanning?
=======================
KSM evaluates all the candidate pages for each scan. It does not use historic
information from previous scans. This has the effect that candidate pages that
couldn't be used for KSM de-duplication continue to be evaluated for each scan.

The idea of "smart scanning" is to keep historic information. With the historic
information we can temporarily skip the candidate page for one or several scans.

Details:
========
"Smart scanning" is to keep two small counters to store if the page has been
used for KSM. One counter stores how often we already tried to use the page for
KSM and the other counter stores how often we skip a page.

How often we skip the candidate page depends how often a page failed KSM
de-duplication. The code skips a maximum of 8 times. During testing this has
shown to be a good compromise for different workloads.

New sysfs knob:
===============
Smart scanning is not enabled by default. With /sys/kernel/mm/ksm/smart_scan
smart scanning can be enabled.

Monitoring:
===========
To monitor how effective smart scanning is a new sysfs knob has been introduced.
/sys/kernel/mm/pages_skipped report how many pages have been skipped by smart
scanning.

Results:
========
- Various workloads have shown a 20% - 25% reduction in page scans
  For the instagram workload for instance, the number of pages scanned has been
  reduced from over 20M pages per scan to less than 15M pages.
- Less pages scans also resulted in an overall higher de-duplication rate as
  some shorter lived pages could be de-duplicated additionally
- Less pages scanned allows to reduce the pages_to_scan parameter
  and this resulted in  a 25% reduction in terms of CPU.
- The improvements have been observed for workloads that enable KSM with
  madvise as well as prctl


This patch (of 4):

This change adds a "smart" page scanning mode for KSM.  So far all the
candidate pages are continuously scanned to find candidates for
de-duplication.  There are a considerably number of pages that cannot be
de-duplicated.  This is costly in terms of CPU.  By using smart scanning
considerable CPU savings can be achieved.

This change takes the history of scanning pages into account and skips the
page scanning of certain pages for a while if de-deduplication for this
page has not been successful in the past.

To do this it introduces two new fields in the ksm_rmap_item structure:
age and remaining_skips.  age, is the KSM age and remaining_skips
determines how often scanning of this page is skipped.  The age field is
incremented each time the page is scanned and the page cannot be de-
duplicated.  age updated is capped at U8_MAX.

How often a page is skipped is dependent how often de-duplication has been
tried so far and the number of skips is currently limited to 8.  This
value has shown to be effective with different workloads.

The feature is currently disable by default and can be enabled with the
new smart_scan knob.

The feature has shown to be very effective: upt to 25% of the page scans
can be eliminated; the pages_to_scan rate can be reduced by 40 - 50% and a
similar de-duplication rate can be maintained.

[akpm@linux-foundation.org: make ksm_smart_scan default true, for testing]
Link: https://lkml.kernel.org/r/20230926040939.516161-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20230926040939.516161-2-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:39 -07:00
Huang Ying
6bc2cfdf82 dax, kmem: calculate abstract distance with general interface 
Previously, a fixed abstract distance MEMTIER_DEFAULT_DAX_ADISTANCE is
used for slow memory type in kmem driver.  This limits the usage of kmem
driver, for example, it cannot be used for HBM (high bandwidth memory).

So, we use the general abstract distance calculation mechanism in kmem
drivers to get more accurate abstract distance on systems with proper
support.  The original MEMTIER_DEFAULT_DAX_ADISTANCE is used as fallback
only.

Now, multiple memory types may be managed by kmem.  These memory types are
put into the "kmem_memory_types" list and protected by
kmem_memory_type_lock.

Link: https://lkml.kernel.org/r/20230926060628.265989-5-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Tested-by: Bharata B Rao <bharata@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Rafael J Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:39 -07:00
Huang Ying
3718c02dbd acpi, hmat: calculate abstract distance with HMAT 
A memory tiering abstract distance calculation algorithm based on ACPI
HMAT is implemented.  The basic idea is as follows.

The performance attributes of system default DRAM nodes are recorded as
the base line.  Whose abstract distance is MEMTIER_ADISTANCE_DRAM.  Then,
the ratio of the abstract distance of a memory node (target) to
MEMTIER_ADISTANCE_DRAM is scaled based on the ratio of the performance
attributes of the node to that of the default DRAM nodes.

The functions to record the read/write latency/bandwidth of the default
DRAM nodes and calculate abstract distance according to read/write
latency/bandwidth ratio will be used by CXL CDAT (Coherent Device
Attribute Table) and other memory device drivers.  So, they are put in
memory-tiers.c.

Link: https://lkml.kernel.org/r/20230926060628.265989-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Tested-by: Bharata B Rao <bharata@amd.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Rafael J Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:39 -07:00
Huang Ying
07a8bdd412 memory tiering: add abstract distance calculation algorithms management 
Patch series "memory tiering: calculate abstract distance based on ACPI
HMAT", v4.

We have the explicit memory tiers framework to manage systems with
multiple types of memory, e.g., DRAM in DIMM slots and CXL memory devices.
Where, same kind of memory devices will be grouped into memory types,
then put into memory tiers.  To describe the performance of a memory type,
abstract distance is defined.  Which is in direct proportion to the memory
latency and inversely proportional to the memory bandwidth.  To keep the
code as simple as possible, fixed abstract distance is used in dax/kmem to
describe slow memory such as Optane DCPMM.

To support more memory types, in this series, we added the abstract
distance calculation algorithm management mechanism, provided a algorithm
implementation based on ACPI HMAT, and used the general abstract distance
calculation interface in dax/kmem driver.  So, dax/kmem can support HBM
(high bandwidth memory) in addition to the original Optane DCPMM.


This patch (of 4):

The abstract distance may be calculated by various drivers, such as ACPI
HMAT, CXL CDAT, etc.  While it may be used by various code which hot-add
memory node, such as dax/kmem etc.  To decouple the algorithm users and
the providers, the abstract distance calculation algorithms management
mechanism is implemented in this patch.  It provides interface for the
providers to register the implementation, and interface for the users.

Multiple algorithm implementations can cooperate via calculating abstract
distance for different memory nodes.  The preference of algorithm
implementations can be specified via priority (notifier_block.priority).

Link: https://lkml.kernel.org/r/20230926060628.265989-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20230926060628.265989-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Tested-by: Bharata B Rao <bharata@amd.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Rafael J Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:38 -07:00
Sidhartha Kumar
a48bf7b475 mm/hugetlb: replace page_ref_freeze() with folio_ref_freeze() in hugetlb_folio_init_vmemmap() 
No functional difference, folio_ref_freeze() is currently a wrapper for
page_ref_freeze().

Link: https://lkml.kernel.org/r/20230926174433.81241-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com> 
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:38 -07:00
Sidhartha Kumar
a08c7193e4 mm/filemap: remove hugetlb special casing in filemap.c 
Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size.  The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added.  These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch. 
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache().  This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
    2MB Page Size
        6.5-rc3 + this patch:
            [root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
            real    1m49.568s
            user    0m0.000s
            sys     1m49.461s

        6.5-rc3:
            [root]# time fallocate -l 700GB test.txt
            real    1m47.495s
            user    0m0.000s
            sys     1m47.370s
    1GB Page Size
        6.5-rc3 + this patch:
            [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
            real    1m47.024s
            user    0m0.000s
            sys     1m46.921s

        6.5-rc3:
            [root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
            real    1m44.551s
            user    0m0.000s
            sys     1m44.438s

x86
    2MB Page Size
        6.5-rc3 + this patch:
            [root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
            real    0m22.383s
            user    0m0.000s
            sys     0m22.255s

        6.5-rc3:
            [opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
            real    0m22.735s
            user    0m0.038s
            sys     0m22.567s

    1GB Page Size
        6.5-rc3 + this patch:
            [root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
            real    0m25.786s
            user    0m0.001s
            sys     0m25.589s

        6.5-rc3:
            [root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
            real    0m33.454s
            user    0m0.001s
            sys     0m33.193s

aarch64:
    workload - fallocate a 700GB file backed by huge pages

    6.5-rc3 + this patch:
        2MB Page Size:
            --100.00%--__arm64_sys_fallocate
                          ksys_fallocate
                          vfs_fallocate
                          hugetlbfs_fallocate
                          |
                          |--95.04%--__pi_clear_page
                          |
                          |--3.57%--clear_huge_page
                          |          |
                          |          |--2.63%--rcu_all_qs
                          |          |
                          |           --0.91%--__cond_resched
                          |
                           --0.67%--__cond_resched
            0.17%     0.00%             0  fallocate  [kernel.vmlinux]       [k] hugetlb_add_to_page_cache
            0.14%     0.10%            11  fallocate  [kernel.vmlinux]       [k] __filemap_add_folio

    6.5-rc3
        2MB Page Size:
                --100.00%--__arm64_sys_fallocate
                          ksys_fallocate
                          vfs_fallocate
                          hugetlbfs_fallocate
                          |
                          |--94.91%--__pi_clear_page
                          |
                          |--4.11%--clear_huge_page
                          |          |
                          |          |--3.00%--rcu_all_qs
                          |          |
                          |           --1.10%--__cond_resched
                          |
                           --0.59%--__cond_resched
            0.08%     0.01%             1  fallocate  [kernel.kallsyms]  [k] hugetlb_add_to_page_cache
            0.05%     0.03%             3  fallocate  [kernel.kallsyms]  [k] __filemap_add_folio

x86
    workload - fallocate a 100GB file backed by huge pages

    6.5-rc3 + this patch:
        2MB Page Size:
            hugetlbfs_fallocate
            |
            --99.57%--clear_huge_page
                |
                --98.47%--clear_page_erms
                    |
                    --0.53%--asm_sysvec_apic_timer_interrupt

            0.04%     0.04%             1  fallocate  [kernel.kallsyms]     [k] xa_load
            0.04%     0.00%             0  fallocate  [kernel.kallsyms]     [k] hugetlb_add_to_page_cache
            0.04%     0.00%             0  fallocate  [kernel.kallsyms]     [k] __filemap_add_folio
            0.04%     0.00%             0  fallocate  [kernel.kallsyms]     [k] xas_store

    6.5-rc3
        2MB Page Size:
                --99.93%--__x64_sys_fallocate
                          vfs_fallocate
                          hugetlbfs_fallocate
                          |
                           --99.38%--clear_huge_page
                                     |
                                     |--98.40%--clear_page_erms
                                     |
                                      --0.59%--__cond_resched
            0.03%     0.03%             1  fallocate  [kernel.kallsyms]  [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
*                      2M
*                      32-bit 64-bit
*     Total testcases:   110    113
*             Skipped:     0      0
*                PASS:   107    113
*                FAIL:     0      0
*    Killed by signal:     3      0
*   Bad configuration:     0      0
*       Expected FAIL:     0      0
*     Unexpected PASS:     0      0
*    Test not present:     0      0
* Strange test result:     0      0
**********

    Done executing testcases.
    LTP Version:  20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
  Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:38 -07:00
Huan Yang
987ffa5a38 mm/damon/core: remove unnecessary si_meminfo invoke. 
si_meminfo() will read and assign more info not just free/ram pages.  For
just DAMOS_WMARK_FREE_MEM_RATE use, only get free and ram pages is ok to
save cpu.

Link: https://lkml.kernel.org/r/20230920015727.4482-1-link@vivo.com
Signed-off-by: Huan Yang <link@vivo.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:38 -07:00
Kefeng Wang
8c9ae56dc7 sched/numa, mm: make numa migrate functions to take a folio 
The cpupid (or access time) is stored in the head page for THP, so it is
safely to make should_numa_migrate_memory() and numa_hint_fault_latency()
to take a folio.  This is in preparation for large folio numa balancing.

Link: https://lkml.kernel.org/r/20230921074417.24004-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:38 -07:00
Kefeng Wang
75c70128a6 mm: mempolicy: make mpol_misplaced() to take a folio 
In preparation for large folio numa balancing, make mpol_misplaced() to
take a folio, no functional change intended.

Link: https://lkml.kernel.org/r/20230921074417.24004-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:37 -07:00
Kefeng Wang
cda6d93672 mm: memory: make numa_migrate_prep() to take a folio 
In preparation for large folio numa balancing, make numa_migrate_prep() to
take a folio, no functional change intended.

Link: https://lkml.kernel.org/r/20230921074417.24004-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:37 -07:00
Kefeng Wang
6695cf68b1 mm: memory: use a folio in do_numa_page() 
Numa balancing only try to migrate non-compound page in do_numa_page(),
use a folio in it to save several compound_head calls, note we use
folio_estimated_sharers(), it is enough to check the folio sharers since
only normal page is handled, if large folio numa balancing is supported, a
precise folio sharers check would be used, no functional change intended.

Link: https://lkml.kernel.org/r/20230921074417.24004-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:37 -07:00
Kefeng Wang
667ffc31aa mm: huge_memory: use a folio in do_huge_pmd_numa_page() 
Use a folio in do_huge_pmd_numa_page(), reduce three page_folio() calls to
one, no functional change intended.

Link: https://lkml.kernel.org/r/20230921074417.24004-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:37 -07:00
Kefeng Wang
6561045345 mm: memory: add vm_normal_folio_pmd() 
Patch series "mm: convert numa balancing functions to use a folio", v2.

do_numa_pages() only handles non-compound pages, and only PMD-mapped THPs
are handled in do_huge_pmd_numa_page().  But a large, PTE-mapped folio
will be supported so let's convert more numa balancing functions to
use/take a folio in preparation for that, no functional change intended
for now.


This patch (of 6):

The new vm_normal_folio_pmd() wrapper is similar to vm_normal_folio(),
which allow them to completely replace the struct page variables with
struct folio variables.

Link: https://lkml.kernel.org/r/20230921074417.24004-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20230921074417.24004-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-16 15:44:37 -07:00
Catalin Marinas
c15cdea517 mm: slab: Do not create kmalloc caches smaller than arch_slab_minalign() 
Commit b035f5a6d8 ("mm: slab: reduce the kmalloc() minimum alignment
if DMA bouncing possible") allows architectures with non-coherent DMA to
define a small ARCH_KMALLOC_MINALIGN (e.g. sizeof(unsigned long long))
and this has been enabled on arm64. With KASAN_HW_TAGS enabled, however,
ARCH_SLAB_MINALIGN becomes 16 on arm64 (arch_slab_minalign() dynamically
selects it since commit d949a8155d ("mm: make minimum slab alignment a
runtime property")). This can lead to a situation where kmalloc-8 caches
are attempted to be created with a kmem_caches.size aligned to 16. When
the cache is mergeable, it can lead to kernel warnings like:

sysfs: cannot create duplicate filename '/kernel/slab/:d-0000016'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.6.0-rc1-00001-gda98843cd306-dirty #5
Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
Call trace:
 dump_backtrace+0x90/0xe8
 show_stack+0x18/0x24
 dump_stack_lvl+0x48/0x60
 dump_stack+0x18/0x24
 sysfs_warn_dup+0x64/0x80
 sysfs_create_dir_ns+0xe8/0x108
 kobject_add_internal+0x98/0x264
 kobject_init_and_add+0x8c/0xd8
 sysfs_slab_add+0x12c/0x248
 slab_sysfs_init+0x98/0x14c
 do_one_initcall+0x6c/0x1b0
 kernel_init_freeable+0x1c0/0x288
 kernel_init+0x24/0x1e0
 ret_from_fork+0x10/0x20
kobject: kobject_add_internal failed for :d-0000016 with -EEXIST, don't try to register things with the same name in the same directory.
SLUB: Unable to add boot slab dma-kmalloc-8 to sysfs

Limit the __kmalloc_minalign() return value (used to create the
kmalloc-* caches) to arch_slab_minalign() so that kmalloc-8 caches are
skipped when KASAN_HW_TAGS is enabled (both config and runtime).

Reported-by: Mark Rutland <mark.rutland@arm.com>
Fixes: b035f5a6d8 ("mm: slab: reduce the kmalloc() minimum alignment if DMA bouncing possible")
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: stable@vger.kernel.org # 6.5.x
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
 2023-10-11 15:24:49 +02:00
Wedson Almeida Filho
2f5028604f
shmem: move shmem_xattr_handlers to .rodata 
This makes it harder for accidental or malicious changes to
shmem_xattr_handlers at runtime.

Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230930050033.41174-29-wedsonaf@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2023-10-10 13:49:20 +02:00
Ingo Molnar
8db30574db Merge branch 'sched/urgent' into sched/core, to pick up fixes and refresh the branch 
Signed-off-by: Ingo Molnar <mingo@kernel.org>
 2023-10-07 11:32:24 +02:00
Minjie Du
d98388cef5 mm/filemap: increase usage of folio_next_index() helper 
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using
the existing helper folio_next_index() in filemap_map_pages().

Link: https://lkml.kernel.org/r/20230921081535.3398-1-duminjie@vivo.com
Signed-off-by: Minjie Du <duminjie@vivo.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:44:11 -07:00
liwenyu
76a0fb4fd5 delayacct: add memory reclaim delay in get_page_from_freelist 
The current memory reclaim delay statistics only count the direct memory
reclaim of the task in do_try_to_free_pages().  In systems with NUMA open,
some tasks occasionally experience slower response times, but the total
count of reclaim does not increase, using ftrace can show that
node_reclaim has occurred.

The memory reclaim occurring in get_page_from_freelist() is also due to
heavy memory load.  To get the impact of tasks in memory reclaim, this
patch adds the statistics of the memory reclaim delay statistics for
__node_reclaim().

Link: https://lkml.kernel.org/r/181C946095F0252B+7cc60eca-1abf-4502-aad3-ffd8ef89d910@ex.bilibili.com
Signed-off-by: Wen Yu Li <wenyuli@ex.bilibili.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: <wangyun@bilibili.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:44:10 -07:00
Liu Shixin
840ea53a8d memcg: remove unused do_memsw_account in memcg1_stat_format 
Since commit b25806dcd3d5("mm: memcontrol: deprecate swapaccounting=0
mode") do_memsw_account() is synonymous with
!cgroup_subsys_on_dfl(memory_cgrp_subsys), It always equals true in
memcg1_stat_format().  Remove the unused code.

Link: https://lkml.kernel.org/r/20230915105845.3199656-3-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Suggested-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Tejun heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:44:10 -07:00
Liu Shixin
72a14e821c memcg: expose swapcache stat for memcg v1 
Patch series "Expose swapcache stat for memcg v1", v2.

Since commit b603894248 ("mm: memcg: add swapcache stat for memcg v2")
adds swapcache stat for the cgroup v2, it seems there is no reason to hide
it in memcg v1.  Conversely, with swapcached it is more accurate to
evaluate the available memory for memcg.

Link: https://lkml.kernel.org/r/20230915105845.3199656-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20230915105845.3199656-2-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:44:10 -07:00
Li Zhijian
51a23b1be9 acpi,mm: fix typo sibiling -> sibling 
First found this typo as reviewing memory tier code. Fix it by sed like:
$ sed -i 's/sibiling/sibling/g' $(git grep -l sibiling)

so the acpi one will be corrected as well.

Link: https://lkml.kernel.org/r/20230802092856.819328-1-lizhijian@cn.fujitsu.com
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:44:10 -07:00
Gregory Price
229e225376 mm/migrate: fix do_pages_move for compat pointers 
do_pages_move does not handle compat pointers for the page list. 
correctly.  Add in_compat_syscall check and appropriate get_user fetch
when iterating the page list.

It makes the syscall in compat mode (32-bit userspace, 64-bit kernel)
work the same way as the native 32-bit syscall again, restoring the
behavior before my broken commit 5b1b561ba7 ("mm: simplify
compat_sys_move_pages").

More specifically, my patch moved the parsing of the 'pages' array from
the main entry point into do_pages_stat(), which left the syscall
working correctly for the 'stat' operation (nodes = NULL), while the
'move' operation (nodes != NULL) is now missing the conversion and
interprets 'pages' as an array of 64-bit pointers instead of the
intended 32-bit userspace pointers.

It is possible that nobody noticed this bug because the few
applications that actually call move_pages are unlikely to run in
compat mode because of their large memory requirements, but this
clearly fixes a user-visible regression and should have been caught by
ltp.

Link: https://lkml.kernel.org/r/20231003144857.752952-1-gregory.price@memverge.com
Fixes: 5b1b561ba7 ("mm: simplify compat_sys_move_pages")
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Liam R. Howlett
824135c46b mmap: fix error paths with dup_anon_vma() 
When the calling function fails after the dup_anon_vma(), the
duplication of the anon_vma is not being undone.  Add the necessary
unlink_anon_vma() call to the error paths that are missing them.

This issue showed up during inspection of the error path in vma_merge()
for an unrelated vma iterator issue.

Users may experience increased memory usage, which may be problematic as
the failure would likely be caused by a low memory situation.

Link: https://lkml.kernel.org/r/20230929183041.2835469-3-Liam.Howlett@oracle.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Liam R. Howlett
1419430c8a mmap: fix vma_iterator in error path of vma_merge() 
During the error path, the vma iterator may not be correctly positioned or
set to the correct range.  Undo the vma_prev() call by resetting to the
passed in address.  Re-walking to the same range will fix the range to the
area previously passed in.

Users would notice increased cycles as vma_merge() would be called an
extra time with vma == prev, and thus would fail to merge and return.

Link: https://lore.kernel.org/linux-mm/CAG48ez12VN1JAOtTNMY+Y2YnsU45yL5giS-Qn=ejtiHpgJAbdQ@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230929183041.2835469-2-Liam.Howlett@oracle.com
Fixes: 18b098af28 ("vma_merge: set vma iterator to correct position.")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Jann Horn <jannh@google.com>
Closes: https://lore.kernel.org/linux-mm/CAG48ez12VN1JAOtTNMY+Y2YnsU45yL5giS-Qn=ejtiHpgJAbdQ@mail.gmail.com/
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Sebastian Ott
e0f81ab1e4 mm: fix vm_brk_flags() to not bail out while holding lock 
Calling vm_brk_flags() with flags set other than VM_EXEC will exit the
function without releasing the mmap_write_lock.

Just do the sanity check before the lock is acquired.  This doesn't fix an
actual issue since no caller sets a flag other than VM_EXEC.

Link: https://lkml.kernel.org/r/20230929171937.work.697-kees@kernel.org
Fixes: 2e7ce7d354 ("mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap()")
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Liam R. Howlett
51f6253775 mm/mempolicy: fix set_mempolicy_home_node() previous VMA pointer 
The two users of mbind_range() are expecting that mbind_range() will
update the pointer to the previous VMA, or return an error.  However,
set_mempolicy_home_node() does not call mbind_range() if there is no VMA
policy.  The fix is to update the pointer to the previous VMA prior to
continuing iterating the VMAs when there is no policy.

Users may experience a WARN_ON() during VMA policy updates when updating
a range of VMAs on the home node.

Link: https://lkml.kernel.org/r/20230928172432.2246534-1-Liam.Howlett@oracle.com
Link: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@mail.gmail.com/
Fixes: f4e9e0e694 ("mm/mempolicy: fix use-after-free of VMA iterator")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Yikebaer Aizezi <yikebaer61@gmail.com>
Closes: https://lore.kernel.org/linux-mm/CALcu4rbT+fMVNaO_F2izaCT+e7jzcAciFkOvk21HGJsmLcUuwQ@mail.gmail.com/
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Kemeng Shi
61e21cf2d2 mm/page_alloc: correct start page when guard page debug is enabled 
When guard page debug is enabled and set_page_guard returns success, we
miss to forward page to point to start of next split range and we will do
split unexpectedly in page range without target page.  Move start page
update before set_page_guard to fix this.

As we split to wrong target page, then splited pages are not able to merge
back to original order when target page is put back and splited pages
except target page is not usable.  To be specific:

Consider target page is the third page in buddy page with order 2.
| buddy-2 | Page | Target | Page |

After break down to target page, we will only set first page to Guard
because of bug.
| Guard   | Page | Target | Page |

When we try put_page_back_buddy with target page, the buddy page of target
if neither guard nor buddy, Then it's not able to construct original page
with order 2
| Guard | Page | buddy-0 | Page |

All pages except target page is not in free list and is not usable.

Link: https://lkml.kernel.org/r/20230927094401.68205-1-shikemeng@huaweicloud.com
Fixes: 06be6ff3d2 ("mm,hwpoison: rework soft offline for free pages")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-06 14:11:38 -07:00
Jakub Kicinski
2606cf059c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 
Cross-merge networking fixes after downstream PR.

No conflicts (or adjacent changes of note).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 2023-10-05 13:16:47 -07:00
Andreas Gruenbacher
6309727ef2 kthread: add kthread_stop_put 
Add a kthread_stop_put() helper that stops a thread and puts its task
struct.  Use it to replace the various instances of kthread_stop()
followed by put_task_struct().

Remove the kthread_stop_put() macro in usbip that is similar but doesn't
return the result of kthread_stop().

[agruenba@redhat.com: fix kerneldoc comment]
  Link: https://lkml.kernel.org/r/20230911111730.2565537-1-agruenba@redhat.com
[akpm@linux-foundation.org: document kthread_stop_put()'s argument]
Link: https://lkml.kernel.org/r/20230907234048.2499820-1-agruenba@redhat.com
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:41:57 -07:00
Yin Fengwei
dc68badced mm: mlock: update mlock_pte_range to handle large folio 
Current kernel only lock base size folio during mlock syscall.
Add large folio support with following rules:
  - Only mlock large folio when it's in VM_LOCKED VMA range
    and fully mapped to page table.

    fully mapped folio is required as if folio is not fully
    mapped to a VM_LOCKED VMA, if system is in memory pressure,
    page reclaim is allowed to pick up this folio, split it
    and reclaim the pages which are not in VM_LOCKED VMA.

  - munlock will apply to the large folio which is in VMA range
    or cross the VMA boundary.

    This is required to handle the case that the large folio is
    mlocked, later the VMA is split in the middle of large folio.

Link: https://lkml.kernel.org/r/20230918073318.1181104-4-fengwei.yin@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
Yin Fengwei
1acbc3f936 mm: handle large folio when large folio in VM_LOCKED VMA range 
If large folio is in the range of VM_LOCKED VMA, it should be mlocked to
avoid being picked by page reclaim.  Which may split the large folio and
then mlock each pages again.

Mlock this kind of large folio to prevent them being picked by page
reclaim.

For the large folio which cross the boundary of VM_LOCKED VMA or not fully
mapped to VM_LOCKED VMA, we'd better not to mlock it.  So if the system is
under memory pressure, this kind of large folio will be split and the
pages ouf of VM_LOCKED VMA can be reclaimed.

Ideally, for large folio, we should mlock it when the large folio is fully
mapped to VMA and munlock it if any page are unmampped from VMA.  But it's
not easy to detect whether the large folio is fully mapped to VMA in some
cases (like add/remove rmap).  So we update mlock_vma_folio() and
munlock_vma_folio() to mlock/munlock the folio according to vma->vm_flags.
Let caller to decide whether they should call these two functions.

For add rmap, only mlock normal 4K folio and postpone large folio handling
to page reclaim phase.  It is possible to reuse page table iterator to
detect whether folio is fully mapped or not during page reclaim phase. 
For remove rmap, invoke munlock_vma_folio() to munlock folio unconditionly
because rmap makes folio not fully mapped to VMA.

Link: https://lkml.kernel.org/r/20230918073318.1181104-3-fengwei.yin@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
Yin Fengwei
28e566572a mm: add functions folio_in_range() and folio_within_vma() 
Patch series "support large folio for mlock", v3.

Yu mentioned at [1] about the mlock() can't be applied to large folio.

I leant the related code and here is my understanding:

- For RLIMIT_MEMLOCK related, there is no problem.  Because the
  RLIMIT_MEMLOCK statistics is not related underneath page.  That means
  underneath page mlock or munlock doesn't impact the RLIMIT_MEMLOCK
  statistics collection which is always correct.

- For keeping the page in RAM, there is no problem either.  At least,
  during try_to_unmap_one(), once detect the VMA has VM_LOCKED bit set in
  vm_flags, the folio will be kept whatever the folio is mlocked or not.

So the function of mlock for large folio works.  But it's not optimized
because the page reclaim needs scan these large folio and may split them.

This series identified the large folio for mlock to four types:
  - The large folio is in VM_LOCKED range and fully mapped to the
    range

  - The large folio is in the VM_LOCKED range but not fully mapped to
    the range

  - The large folio cross VM_LOCKED VMA boundary

  - The large folio cross last level page table boundary

For the first type, we mlock large folio so page reclaim will skip it.

For the second/third type, we don't mlock large folio.  As the pages not
mapped to VM_LOACKED range are mapped to none VM_LOCKED range, if system
is in memory pressure situation, the large folio can be picked by page
reclaim and split.  Then the pages not mapped to VM_LOCKED range can be
reclaimed.

For the fourth type, we don't mlock large folio because locking one page
table lock can't prevent the part in another last level page table being
unmapped.  Thanks to Ryan for pointing this out.


To check whether the folio is fully mapped to the range, PTEs needs be
checked to see whether the page of folio is associated.  Which needs take
page table lock and is heavy operation.  So far, the only place needs this
check is madvise and page reclaim.  These functions already have their own
PTE iterator.

patch1 introduce API to check whether large folio is in VMA range.
patch2 make page reclaim/mlock_vma_folio/munlock_vma_folio support
       large folio mlock/munlock.
patch3 make mlock/munlock syscall support large folio.

Yu also mentioned a race which can make folio unevictable after munlock
during RFC v2 discussion [3]:
We decided that race issue didn't block this series based on:
  - That race issue was not introduced by this series

  - We had a looks-ok fix for that race issue. Need to wait
    for mlock_count fixing patch as Yosry Ahmed suggested [4]

[1] https://lore.kernel.org/linux-mm/CAOUHufbtNPkdktjt_5qM45GegVO-rCFOMkSh0HQminQ12zsV8Q@mail.gmail.com/
[2] https://lore.kernel.org/linux-mm/20230809061105.3369958-1-fengwei.yin@intel.com/
[3] https://lore.kernel.org/linux-mm/CAOUHufZ6=9P_=CAOQyw0xw-3q707q-1FVV09dBNDC-hpcpj2Pg@mail.gmail.com/


This patch (of 3):

folio_in_range() will be used to check whether the folio is mapped to
specific VMA and whether the mapping address of folio is in the range.

Also a helper function folio_within_vma() to check whether folio
is in the range of vma based on folio_in_range().

Link: https://lkml.kernel.org/r/20230918073318.1181104-1-fengwei.yin@intel.com
Link: https://lkml.kernel.org/r/20230918073318.1181104-2-fengwei.yin@intel.com
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
Jinjie Ruan
a0ce79253a mm/damon/core-test: fix memory leak in damon_new_ctx() 
When CONFIG_DAMON_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y and
CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

The damon_ctx which is allocated by kzalloc() in damon_new_ctx() in
damon_test_ops_registration() and damon_test_set_attrs() are not freed. 
So use damon_destroy_ctx() to free it.  After applying this patch, the
following memory leak is never detected

    unreferenced object 0xffff2b49c6968800 (size 512):
      comm "kunit_try_catch", pid 350, jiffies 4294895294 (age 557.028s)
      hex dump (first 32 bytes):
        88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00  ................
        00 87 93 03 00 00 00 00 0a 00 00 00 00 00 00 00  ................
      backtrace:
        [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
        [<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
        [<00000000b5f89cef>] kmalloc_trace+0x40/0x164
        [<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
        [<00000000daf6227b>] damon_test_ops_registration+0x34/0x328
        [<00000000559c4801>] kunit_try_run_case+0x50/0xac
        [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
        [<000000003c3e9211>] kthread+0x124/0x130
        [<0000000028f85bdd>] ret_from_fork+0x10/0x20
    unreferenced object 0xffff2b49c1a9cc00 (size 512):
      comm "kunit_try_catch", pid 356, jiffies 4294895306 (age 557.000s)
      hex dump (first 32 bytes):
        88 13 00 00 00 00 00 00 a0 86 01 00 00 00 00 00  ................
        00 00 00 00 00 00 00 00 0a 00 00 00 00 00 00 00  ................
      backtrace:
        [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
        [<0000000073acab3b>] __kmem_cache_alloc_node+0x174/0x290
        [<00000000b5f89cef>] kmalloc_trace+0x40/0x164
        [<00000000eb19e83f>] damon_new_ctx+0x28/0xb4
        [<00000000058495c4>] damon_test_set_attrs+0x30/0x1a8
        [<00000000559c4801>] kunit_try_run_case+0x50/0xac
        [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
        [<000000003c3e9211>] kthread+0x124/0x130
        [<0000000028f85bdd>] ret_from_fork+0x10/0x20

Link: https://lkml.kernel.org/r/20230918120951.2230468-3-ruanjinjie@huawei.com
Fixes: d1836a3b2a ("mm/damon/core-test: initialise context before test in damon_test_set_attrs()")
Fixes: 4f540f5ab4 ("mm/damon/core-test: add a kunit test case for ops registration")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
Jinjie Ruan
f950fa6ec6 mm/damon/core-test: fix memory leak in damon_new_region() 
Patch series "mm/damon/core-test: Fix memory leaks in core-test", v3.

There are a few memory leaks in core-test which are detected by kmemleak. 
This patchset fixes the issues.


This patch (of 2):

When CONFIG_DAMON_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y
and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

The damon_region which is allocated by kmem_cache_alloc() in
damon_new_region() in damon_test_regions() and
damon_test_update_monitoring_result() are not freed.

So for damon_test_regions(), replace damon_del_region() call with
damon_destroy_region() so that it calls both damon_del_region() and
damon_free_region(), the latter will free the damon_region. For
damon_test_update_monitoring_result(), call damon_free_region() to
free it. After applying this patch, the following memory leak is never
detected.

    unreferenced object 0xffff2b49c3edc000 (size 56):
      comm "kunit_try_catch", pid 338, jiffies 4294895280 (age 557.084s)
      hex dump (first 32 bytes):
        01 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00  ................
        00 00 00 00 00 00 00 00 00 00 00 00 49 2b ff ff  ............I+..
      backtrace:
        [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
        [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284
        [<000000008603f022>] damon_new_region+0x28/0x54
        [<00000000a3b8c64e>] damon_test_regions+0x38/0x270
        [<00000000559c4801>] kunit_try_run_case+0x50/0xac
        [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
        [<000000003c3e9211>] kthread+0x124/0x130
        [<0000000028f85bdd>] ret_from_fork+0x10/0x20
    unreferenced object 0xffff2b49c5b20000 (size 56):
      comm "kunit_try_catch", pid 354, jiffies 4294895304 (age 556.988s)
      hex dump (first 32 bytes):
        03 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00  ................
        00 00 00 00 00 00 00 00 96 00 00 00 49 2b ff ff  ............I+..
      backtrace:
        [<0000000088e71769>] slab_post_alloc_hook+0xb8/0x368
        [<00000000b528f67c>] kmem_cache_alloc+0x168/0x284
        [<000000008603f022>] damon_new_region+0x28/0x54
        [<00000000ca019f80>] damon_test_update_monitoring_result+0x18/0x34
        [<00000000559c4801>] kunit_try_run_case+0x50/0xac
        [<000000003932ed49>] kunit_generic_run_threadfn_adapter+0x20/0x2c
        [<000000003c3e9211>] kthread+0x124/0x130
        [<0000000028f85bdd>] ret_from_fork+0x10/0x20

Link: https://lkml.kernel.org/r/20230918120951.2230468-1-ruanjinjie@huawei.com
Link: https://lkml.kernel.org/r/20230918120951.2230468-2-ruanjinjie@huawei.com
Fixes: 17ccae8bb5 ("mm/damon: add kunit tests")
Fixes: f4c978b659 ("mm/damon/core-test: add a test for damon_update_monitoring_results()")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: Feng Tang <feng.tang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
Jianguo Bao
ab428b4c45 mm/writeback: update filemap_dirty_folio() comment 
Change to use new address space operation dirty_folio().

Link: https://lkml.kernel.org/r/20230917-trycontrib1-v1-1-db22630b8839@gmail.com
Fixes: 6f31a5a261 ("fs: Add aops->dirty_folio")
Signed-off-by: Jianguo Bau <roidinev@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:32 -07:00
SeongJae Park
a2a9f68e35 mm/damon/sysfs-schemes: support DAMOS apply interval 
Update DAMON sysfs interface to support DAMOS apply intervals by adding a
new file, 'apply_interval_us' in each scheme directory.  Users can set and
get the interval for each scheme in microseconds by writing to and reading
from the file.

Link: https://lkml.kernel.org/r/20230916020945.47296-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
SeongJae Park
42f994b714 mm/damon/core: implement scheme-specific apply interval 
DAMON-based operation schemes are applied for every aggregation interval. 
That was mainly because schemes were using nr_accesses, which be complete
to be used for every aggregation interval.  However, the schemes are now
using nr_accesses_bp, which is updated for each sampling interval in a way
that reasonable to be used.  Therefore, there is no reason to apply
schemes for each aggregation interval.

The unnecessary alignment with aggregation interval was also making some
use cases of DAMOS tricky.  Quotas setting under long aggregation interval
is one such example.  Suppose the aggregation interval is ten seconds, and
there is a scheme having CPU quota 100ms per 1s.  The scheme will actually
uses 100ms per ten seconds, since it cannobe be applied before next
aggregation interval.  The feature is working as intended, but the results
might not that intuitive for some users.  This could be fixed by updating
the quota to 1s per 10s.  But, in the case, the CPU usage of DAMOS could
look like spikes, and would actually make a bad effect to other
CPU-sensitive workloads.

Implement a dedicated timing interval for each DAMON-based operation
scheme, namely apply_interval.  The interval will be sampling interval
aligned, and each scheme will be applied for its apply_interval.  The
interval is set to 0 by default, and it means the scheme should use the
aggregation interval instead.  This avoids old users getting any
behavioral difference.

Link: https://lkml.kernel.org/r/20230916020945.47296-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
SeongJae Park
e7639bb48d mm/damon/sysfs-schemes: use nr_accesses_bp as the source of tried_regions/<N>/nr_accesses 
DAMON sysfs interface exposes access rate of each region via DAMOS tried
regions directory.  For this, the nr_accesses field of the region is used.
DAMOS was actually using nr_accesses in the past, but it uses
nr_accesses_bp now.  Use the value that it is really using as the source.

Note that this doesn't expose nr_accesses_bp as is (in basis point), but
after converting it to the natural number by dividing the value by 10,000.
Hence there is no behavioral change from users' perspective.

Link: https://lkml.kernel.org/r/20230916020945.47296-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
SeongJae Park
affa87c708 mm/damon/core: make DAMOS uses nr_accesses_bp instead of nr_accesses 
Patch series "mm/damon: implement DAMOS apply intervals".

DAMON-based operation schemes are applied for every aggregation interval. 
That is mainly because schemes are using nr_accesses, which be complete to
be used for every aggregation interval.

This makes some DAMOS use cases be tricky.  Quota setting under long
aggregation interval is one such example.  Suppose the aggregation
interval is ten seconds, and there is a scheme having CPU quota 100ms per
1s.  The scheme will actually uses 100ms per ten seconds, since it cannobe
be applied before next aggregation interval.  The feature is working as
intended, but the results might not that intuitive for some users.  This
could be fixed by updating the quota to 1s per 10s.  But, in the case, the
CPU usage of DAMOS could look like spikes, and actually make a bad effect
to other CPU-sensitive workloads.

Also, with such huge aggregation interval, users may want schemes to be
applied more frequently.

DAMON provides nr_accesses_bp, which is updated for each sampling interval
in a way that reasonable to be used.  By using that instead of
nr_accesses, DAMOS can have its own time interval and mitigate abovely
mentioned issues.

This patchset makes DAMOS schemes to use nr_accesses_bp instead of
nr_accesses, and have their own timing intervals.  Also update DAMOS tried
regions sysfs files and DAMOS before_apply tracepoint to use the new data
as their source.  Note that the interval is zero by default, and it is
interpreted to use the aggregation interval instead.  This avoids making
user-visible behavioral changes.


Patches Seuqeunce
-----------------

The first patch (patch 1/9) makes DAMOS uses nr_accesses_bp instead of
nr_accesses, and following two patches (patches 2/9 and 3/9) updates DAMON
sysfs interface for DAMOS tried regions and the DAMOS before_apply
tracespoint to use nr_accesses_bp instead of nr_accesses, respectively.

The following two patches (patches 4/9 and 5/9) implements the
scheme-specific apply interval for DAMON kernel API users and update the
design document for the new feature.

Finally, the following four patches (patches 6/9, 7/9, 8/9 and 9/9) add
support of the feature in DAMON sysfs interface, add a simple selftest
test case, and document the new file on the usage and the ABI documents,
repsectively.


This patch (of 9):

DAMON provides nr_accesses_bp, which becomes same to nr_accesses * 10000
for every aggregation interval, but updated every sampling interval with a
reasonable accuracy.  Since DAMON-based operation schemes are applied in
every aggregation interval using nr_accesses, using nr_accesses_bp instead
will make no difference to users.  Meanwhile, it allows DAMOS to apply the
schemes in a time interval that less than the aggregation interval.  It
could be useful and more flexible for some cases.  Do it.

Link: https://lkml.kernel.org/r/20230916020945.47296-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230916020945.47296-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
Matthew Wilcox (Oracle)
d5b43e9683 hugetlb: convert remove_pool_huge_page() to remove_pool_hugetlb_folio() 
Convert the callers to expect a folio and remove the unnecesary conversion
back to a struct page.

Link: https://lkml.kernel.org/r/20230824141325.2704553-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
Matthew Wilcox (Oracle)
04bbfd844b hugetlb: remove a few calls to page_folio() 
Anything found on a linked list threaded through ->lru is guaranteed to be
a folio as the compound_head found in a tail page overlaps the ->lru
member of struct page.  So we can pull folios directly off these lists no
matter whether pages or folios were added to the list.

Link: https://lkml.kernel.org/r/20230824141325.2704553-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
Matthew Wilcox (Oracle)
3ec145f9d0 hugetlb: use a folio in free_hpage_workfn() 
Patch series "Small hugetlb cleanups", v2.

Some trivial folio conversions


This patch (of 3):

update_and_free_hugetlb_folio puts the memory on hpage_freelist as a folio
so we can take it off the list as a folio.

Link: https://lkml.kernel.org/r/20230824141325.2704553-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230824141325.2704553-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:31 -07:00
Usama Arif
fde1c4ecf9 mm: hugetlb: skip initialization of gigantic tail struct pages if freed by HVO 
The new boot flow when it comes to initialization of gigantic pages is as
follows:

- At boot time, for a gigantic page during __alloc_bootmem_hugepage, the
  region after the first struct page is marked as noinit.

- This results in only the first struct page to be initialized in
  reserve_bootmem_region.  As the tail struct pages are not initialized at
  this point, there can be a significant saving in boot time if HVO
  succeeds later on.

- Later on in the boot, the head page is prepped and the first
  HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages
  are initialized.

- HVO is attempted.  If it is not successful, then the rest of the tail
  struct pages are initialized.  If it is successful, no more tail struct
  pages need to be initialized saving significant boot time.

The WARN_ON for increased ref count in gather_bootmem_prealloc was changed
to a VM_BUG_ON.  This is OK as there should be no speculative references
this early in boot process.  The VM_BUG_ON's are there just in case such
code is introduced.

[akpm@linux-foundation.org: make it nicer for 80 cols]
Link: https://lkml.kernel.org/r/20230913105401.519709-5-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
Usama Arif
77e6c43e13 memblock: introduce MEMBLOCK_RSRV_NOINIT flag 
For reserved memory regions marked with this flag, reserve_bootmem_region
is not called during memmap_init_reserved_pages.  This can be used to
avoid struct page initialization for regions which won't need them, for
e.g.  hugepages with Hugepage Vmemmap Optimization enabled.

Link: https://lkml.kernel.org/r/20230913105401.519709-4-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
Usama Arif
ee8d2071ef memblock: pass memblock_type to memblock_setclr_flag 
This allows setting flags to both memblock types and is in preparation for
setting flags (for e.g.  to not initialize struct pages) on reserved
memory region.

[usama.arif@bytedance.com: add missing argument definition]
  Link: https://lkml.kernel.org/r/20230918090657.220463-1-usama.arif@bytedance.com
Link: https://lkml.kernel.org/r/20230913105401.519709-3-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
Usama Arif
a9e34ea1f6 mm: hugetlb_vmemmap: use nid of the head page to reallocate it 
Patch series "mm: hugetlb: Skip initialization of gigantic tail struct
pages if freed by HVO", v5.

This series moves the boot time initialization of tail struct pages of a
gigantic page to later on in the boot.  Only the
HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages
are initialized at the start.  If HVO is successful, then no more tail
struct pages need to be initialized.  For a 1G hugepage, this series avoid
initialization of 262144 - 63 = 262081 struct pages per hugepage.

When tested on a 512G system (allocating 500 1G hugepages), the kexec-boot
times with DEFERRED_STRUCT_PAGE_INIT enabled are:

- with patches, HVO enabled: 1.32 seconds
- with patches, HVO disabled: 2.15 seconds
- without patches, HVO enabled: 3.90  seconds
- without patches, HVO disabled: 3.58 seconds

This represents an approximately 70% reduction in boot time and will
significantly reduce server downtime when using a large number of gigantic
pages.


This patch (of 4):

If tail page prep and initialization is skipped, then the "start" page
will not contain the correct nid.  Use the nid from first vmemap page.

Link: https://lkml.kernel.org/r/20230913105401.519709-1-usama.arif@bytedance.com
Link: https://lkml.kernel.org/r/20230913105401.519709-2-usama.arif@bytedance.com
Signed-off-by: Usama Arif <usama.arif@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
863803a794 mm/damon/core: mark damon_moving_sum() as a static function 
The function is used by only mm/damon/core.c.  Mark it as a static
function.

Link: https://lkml.kernel.org/r/20230915025251.72816-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
401807a316 mm/damon/core: skip updating nr_accesses_bp for each aggregation interval 
damon_merge_regions_of(), which is called for each aggregation interval,
updates nr_accesses_bp to nr_accesses * 10000.  However, nr_accesses_bp is
updated for each sampling interval via damon_moving_sum() using the
aggregation interval as the moving time window.  And by the definition of
the algorithm, the value becomes same to discrete-window based sum for
each time window-aligned time.  Hence, nr_accesses_bp will be same to
nr_accesses * 10000 for each aggregation interval without explicit update.
Remove the unnecessary update of nr_accesses_bp in
damon_merge_regions_of().

Link: https://lkml.kernel.org/r/20230915025251.72816-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
ace30fb21a mm/damon/core: use pseudo-moving sum for nr_accesses_bp 
Let nr_accesses_bp be calculated as a pseudo-moving sum that updated for
every sampling interval, using damon_moving_sum().  This is assumed to be
useful for cases that the aggregation interval is set quite huge, but the
monivoting results need to be collected earlier than next aggregation
interval is passed.

Link: https://lkml.kernel.org/r/20230915025251.72816-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
80333828ea mm/damon/core: introduce nr_accesses_bp 
Add yet another representation of the access rate of each region, namely
nr_accesses_bp.  It is just same to the nr_accesses but represents the
value in basis point (1 in 10,000), and updated at once in every
aggregation interval.  That is, moving_accesses_bp is just nr_accesses *
10000.  This may seems useless at the moment.  However, it will be useful
for representing less than one nr_accesses value that will be needed to
make moving sum-based nr_accesses.

Link: https://lkml.kernel.org/r/20230915025251.72816-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
0926e8ff96 mm/damon/core-test: add a unit test for damon_moving_sum() 
Add a simple unit test for the pseudo moving-sum function
(damon_moving_sum()).

Link: https://lkml.kernel.org/r/20230915025251.72816-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
d2c062ade0 mm/damon/core: implement a pseudo-moving sum function 
For values that continuously change, moving average or sum are good ways
to provide fast updates while handling temporal and errorneous variability
of the value.  For example, the access rate counter (nr_accesses) is
calculated as a sum of the number of positive sampled access check results
that collected during a discrete time window (aggregation interval), and
hence it handles temporal and errorneous access check results, but
provides the update only for every aggregation interval.  Using a moving
sum method for that could allow providing the value for every sampling
interval.  That could be useful for getting monitoring results snapshot or
running DAMOS in fine-grained timing.

However, supporting the moving sum for cases that number of samples in the
time window is arbirary could impose high overhead, since the number of
past values that it needs to keep could be too high.  The nr_accesses
would also be one of the cases.  To mitigate the overhead, implement a
pseudo-moving sum function that only provides an estimated pseudo-moving
sum.  It assumes there was no error in last discrete time window and
subtract constant portion of last discrete time window sum.

Note that the function is not strictly implementing the moving sum, but it
keeps a property of moving sum, which makes the value same to the
dsicrete-window based sum for each time window-aligned timing.  Hence,
people collecting the value in the old timings would show no difference.

Link: https://lkml.kernel.org/r/20230915025251.72816-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
22a7788038 mm/damon/vaddr: call damon_update_region_access_rate() always 
When getting mm_struct of the monitoring target process fails, there wil
be no need to increase the access rate counter (nr_accesses) of the
regions for the process.  Hence, damon_va_check_accesses() skips calling
damon_update_region_access_rate() in the case.  This breaks the assumption
that damon_update_region_access_rate() is called for every region, for
every sampling interval.  Call the function for every region even in the
case.  This might increase the overhead in some cases, but such case would
not be frequent, so no significant impact is really expected.

Link: https://lkml.kernel.org/r/20230915025251.72816-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:30 -07:00
SeongJae Park
78fbfb155d mm/damon/core: define and use a dedicated function for region access rate update 
Patch series "mm/damon: provide pseudo-moving sum based access rate".

DAMON checks the access to each region for every sampling interval,
increase the access rate counter of the region, namely nr_accesses, if the
access was made.  For every aggregation interval, the counter is reset. 
The counter is exposed to users to be used as a metric showing the
relative access rate (frequency) of each region.  In other words, DAMON
provides access rate of each region in every aggregation interval.  The
aggregation avoids temporal access pattern changes making things
confusing.  However, this also makes a few DAMON-related operations to
unnecessarily need to be aligned to the aggregation interval.  This can
restrict the flexibility of DAMON applications, especially when the
aggregation interval is huge.

To provide the monitoring results in finer-grained timing while keeping
handling of temporal access pattern change, this patchset implements a
pseudo-moving sum based access rate metric.  It is pseudo-moving sum
because strict moving sum implementation would need to keep all values for
last time window, and that could incur high overhead of there could be
arbitrary number of values in a time window.  Especially in case of the
nr_accesses, since the sampling interval and aggregation interval can
arbitrarily set and the past values should be maintained for every region,
it could be risky.  The pseudo-moving sum assumes there were no temporal
access pattern change in last discrete time window to remove the needs for
keeping the list of the last time window values.  As a result, it beocmes
not strict moving sum implementation, but provides a reasonable accuracy.

Also, it keeps an important property of the moving sum.  That is, the
moving sum becomes same to discrete-window based sum at the time that
aligns to the time window.  This means using the pseudo moving sum based
nr_accesses makes no change to users who shows the value for every
aggregation interval.

Patches Sequence
----------------

The sequence of the patches is as follows.  The first four patches are for
preparation of the change.  The first two (patches 1 and 2) implements a
helper function for nr_accesses update and eliminate corner case that
skips use of the function, respectively.  Following two (patches 3 and 4)
respectively implement the pseudo-moving sum function and its simple unit
test case.

Two patches for making DAMON to use the pseudo-moving sum follow.  The
fifthe one (patch 5) introduces a new field for representing the
pseudo-moving sum-based access rate of each region, and the sixth one
makes the new representation to actually updated with the pseudo-moving
sum function.

Last two patches (patches 7 and 8) makes followup fixes for skipping
unnecessary updates and marking the moving sum function as static,
respectively.


This patch (of 8):

Each DAMON operarions set is updating nr_accesses field of each
damon_region for each of their access check results, from the
check_accesses() callback.  Directly accessing the field could make things
complex to manage and change in future.  Define and use a dedicated
function for the purpose.

Link: https://lkml.kernel.org/r/20230915025251.72816-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230915025251.72816-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
SeongJae Park
4472edf63d mm/damon/core: use number of passed access sampling as a timer 
DAMON sleeps for sampling interval after each sampling, and check if the
aggregation interval and the ops update interval have passed using
ktime_get_coarse_ts64() and baseline timestamps for the intervals.  That
design is for making the operations occur at deterministic timing
regardless of the time that spend for each work.  However, it turned out
it is not that useful, and incur not-that-intuitive results.

After all, timer functions, and especially sleep functions that DAMON uses
to wait for specific timing, are not necessarily strictly accurate.  It is
legal design, so no problem.  However, depending on such inaccuracies, the
nr_accesses can be larger than aggregation interval divided by sampling
interval.  For example, with the default setting (5 ms sampling interval
and 100 ms aggregation interval) we frequently show regions having
nr_accesses larger than 20.  Also, if the execution of a DAMOS scheme
takes a long time, next aggregation could happen before enough number of
samples are collected.  This is not what usual users would intuitively
expect.

Since access check sampling is the smallest unit work of DAMON, using the
number of passed sampling intervals as the DAMON-internal timer can easily
avoid these problems.  That is, convert aggregation and ops update
intervals to numbers of sampling intervals that need to be passed before
those operations be executed, count the number of passed sampling
intervals, and invoke the operations as soon as the specific amount of
sampling intervals passed.  Make the change.

Note that this could make a behavioral change to settings that using
intervals that not aligned by the sampling interval.  For example, if the
sampling interval is 5 ms and the aggregation interval is 12 ms, DAMON
effectively uses 15 ms as its aggregation interval, because it checks
whether the aggregation interval after sleeping the sampling interval. 
This change will make DAMON to effectively use 10 ms as aggregation
interval, since it uses 'aggregation interval / sampling interval *
sampling interval' as the effective aggregation interval, and we don't use
floating point types.  Usual users would have used aligned intervals, so
this behavioral change is not expected to make any meaningful impact, so
just make this change.

Link: https://lkml.kernel.org/r/20230914021523.60649-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
Zi Yan
1640a0ef80 mm/memory_hotplug: use pfn math in place of direct struct page manipulation 
When dealing with hugetlb pages, manipulating struct page pointers
directly can get to wrong struct page, since struct page is not guaranteed
to be contiguous on SPARSEMEM without VMEMMAP.  Use pfn calculation to
handle it properly.

Without the fix, a wrong number of page might be skipped. Since skip cannot be
negative, scan_movable_page() will end early and might miss a movable page with
-ENOENT. This might fail offline_pages(). No bug is reported. The fix comes
from code inspection.

Link: https://lkml.kernel.org/r/20230913201248.452081-4-zi.yan@sent.com
Fixes: eeb0efd071 ("mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
Zi Yan
426056efe8 mm/hugetlb: use nth_page() in place of direct struct page manipulation 
When dealing with hugetlb pages, manipulating struct page pointers
directly can get to wrong struct page, since struct page is not guaranteed
to be contiguous on SPARSEMEM without VMEMMAP.  Use nth_page() to handle
it properly.

A wrong or non-existing page might be tried to be grabbed, either
leading to a non freeable page or kernel memory access errors.  No bug
is reported.  It comes from code inspection.

Link: https://lkml.kernel.org/r/20230913201248.452081-3-zi.yan@sent.com
Fixes: 57a196a584 ("hugetlb: simplify hugetlb handling in follow_page_mask")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
Zi Yan
2e7cfe5cd5 mm/cma: use nth_page() in place of direct struct page manipulation 
Patch series "Use nth_page() in place of direct struct page manipulation",
v3.

On SPARSEMEM without VMEMMAP, struct page is not guaranteed to be
contiguous, since each memory section's memmap might be allocated
independently.  hugetlb pages can go beyond a memory section size, thus
direct struct page manipulation on hugetlb pages/subpages might give wrong
struct page.  Kernel provides nth_page() to do the manipulation properly. 
Use that whenever code can see hugetlb pages.


This patch (of 5):

When dealing with hugetlb pages, manipulating struct page pointers
directly can get to wrong struct page, since struct page is not guaranteed
to be contiguous on SPARSEMEM without VMEMMAP.  Use nth_page() to handle
it properly.

Without the fix, page_kasan_tag_reset() could reset wrong page tags,
causing a wrong kasan result.  No related bug is reported.  The fix
comes from code inspection.

Link: https://lkml.kernel.org/r/20230913201248.452081-1-zi.yan@sent.com
Link: https://lkml.kernel.org/r/20230913201248.452081-2-zi.yan@sent.com
Fixes: 2813b9c029 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
Vlastimil Babka
3dfbb555c9 mm, vmscan: remove ISOLATE_UNMAPPED 
This isolate_mode_t flag is effectively unused since 89f6c88a6a ("mm:
__isolate_lru_page_prepare() in isolate_migratepages_block()") as
sc->may_unmap is now checked directly (and only node_reclaim has a mode
that sets it to 0).  The last remaining place is mm_vmscan_lru_isolate
tracepoint for the isolate_mode parameter.  That one was mainly used to
indicate the active/inactive mode, which the trace-vmscan-postprocess.pl
script consumed, but that got silently broken.  After fixing the script by
the previous patch, it does not need the isolate_mode anymore.  So just
remove the parameter and with that the whole ISOLATE_UNMAPPED flag.

Link: https://lkml.kernel.org/r/20230914131637.12204-4-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:29 -07:00
SeongJae Park
c603c630b5 mm/damon/core: add a tracepoint for damos apply target regions 
Patch series "mm/damon: add a tracepoint for damos apply target regions",
v2.

DAMON provides damon_aggregated tracepoint to let users record full
monitoring results.  Sometimes, users need to record monitoring results of
specific pattern.  DAMOS tried regions directory of DAMON sysfs interface
allows it, but the interface is mainly designed for snapshots and
therefore would be inefficient for such recording.  Implement yet another
tracepoint for efficient support of the usecase.


This patch (of 2):

DAMON provides damon_aggregated tracepoint, which exposes details of each
region and its access monitoring results.  It is useful for getting whole
monitoring results, e.g., for recording purposes.

For investigations of DAMOS, DAMON Sysfs interface provides DAMOS
statistics and tried_regions directory.  But, those provides only
statistics and snapshots.  If the scheme is frequently applied and if the
user needs to know every detail of DAMOS behavior, the snapshot-based
interface could be insufficient and expensive.

As a last resort, userspace users need to record the all monitoring
results via damon_aggregated tracepoint and simulate how DAMOS would
worked.  It is unnecessarily complicated.  DAMON kernel API users,
meanwhile, can do that easily via before_damos_apply() callback field of
'struct damon_callback', though.

Add a tracepoint that will be called just after before_damos_apply()
callback for more convenient investigations of DAMOS.  The tracepoint
exposes all details about each regions, similar to damon_aggregated
tracepoint.

Please note that DAMOS is currently not only for memory management but
also for query-like efficient monitoring results retrievals (when 'stat'
action is used).  Until now, only statistics or snapshots were supported. 
Addition of this tracepoint allows efficient full recording of DAMOS-based
filtered monitoring results.

Link: https://lkml.kernel.org/r/20230913022050.2109-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20230913022050.2109-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>	[tracing]
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
fa1df3f628 mm: migrate: remove isolated variable in add_page_for_migration() 
Directly check the return of isolate_hugetlb() and folio_isolate_lru() to
remove isolated variable, also setup err = -EBUSY in advance before
isolation, and update err only when successfully queued for migration,
which could help us to unify and simplify code a bit.

Link: https://lkml.kernel.org/r/20230913095131.2426871-9-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
b426ed7889 mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration() 
There is some different between hugeTLB and THP behave when passed the
address of a tail page, for THP, it will migrate the entire THP page, but
for HugeTLB, it will return -EACCES, or -ENOENT before commit e66f17ff71
("mm/hugetlb: take page table lock in follow_huge_pmd()"),

  -EACCES The page is mapped by multiple processes and can be moved
	  only if MPOL_MF_MOVE_ALL is specified.
  -ENOENT The page is not present.

But when check manual[1], both of the two errnos are not suitable, it is
better to keep the same behave between hugetlb and THP when passed the
address of a tail page, so let's just remove the PageHead() check for
HugeTLB.

[1] https://man7.org/linux/man-pages/man2/move_pages.2.html

Link: https://lkml.kernel.org/r/20230913095131.2426871-8-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
d64cfccbc8 mm: migrate: use a folio in add_page_for_migration() 
Use a folio in add_page_for_migration() to save compound_head() calls.

Link: https://lkml.kernel.org/r/20230913095131.2426871-7-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
7e2a5e5ab2 mm: migrate: use __folio_test_movable() 
Use __folio_test_movable(), no need to convert from folio to page again.

Link: https://lkml.kernel.org/r/20230913095131.2426871-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
73eab3ca48 mm: migrate: convert migrate_misplaced_page() to migrate_misplaced_folio() 
At present, numa balance only support base page and PMD-mapped THP, but we
will expand to support to migrate large folio/pte-mapped THP in the
future, it is better to make migrate_misplaced_page() to take a folio
instead of a page, and rename it to migrate_misplaced_folio(), it is a
preparation, also this remove several compound_head() calls.

Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:28 -07:00
Kefeng Wang
2ac9e99f3b mm: migrate: convert numamigrate_isolate_page() to numamigrate_isolate_folio() 
Rename numamigrate_isolate_page() to numamigrate_isolate_folio(), then
make it takes a folio and use folio API to save compound_head() calls.

Link: https://lkml.kernel.org/r/20230913095131.2426871-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
Kefeng Wang
728be28fae mm: migrate: remove THP mapcount check in numamigrate_isolate_page() 
The check of THP mapped by multiple processes was introduced by commit
04fa5d6a65 ("mm: migrate: check page_count of THP before migrating") and
refactor by commit 340ef3902c ("mm: numa: cleanup flow of transhuge page
migration"), which is out of date, since migrate_misplaced_page() is now
using the standard migrate_pages() for small pages and THPs, the reference
count checking is in folio_migrate_mapping(), so let's remove the special
check for THP.

Link: https://lkml.kernel.org/r/20230913095131.2426871-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
Kefeng Wang
a8ac4a767d mm: migrate: remove PageTransHuge check in numamigrate_isolate_page() 
Patch series "mm: migrate: more folio conversion and unification", v3.

Convert more migrate functions to use a folio, it is also a preparation
for large folio migration support when balancing numa.


This patch (of 8):

The assert VM_BUG_ON_PAGE(order && !PageTransHuge(page), page) is not very
useful,

   1) for a tail/base page, order = 0, for a head page, the order > 0 &&
      PageTransHuge() is true
   2) there is a PageCompound() check and only base page is handled in
      do_numa_page(), and do_huge_pmd_numa_page() only handle PMD-mapped
      THP
   3) even though the page is a tail page, isolate_lru_page() will post
      a warning, and fail to isolate the page
   4) if large folio/pte-mapped THP migration supported in the future,
      we could migrate the entire folio if numa fault on a tail page

so just remove the check.

Link: https://lkml.kernel.org/r/20230913095131.2426871-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20230913095131.2426871-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
09c550508a mm/rmap: pass folio to hugepage_add_anon_rmap() 
Let's pass a folio; we are always mapping the entire thing.

Link: https://lkml.kernel.org/r/20230913125113.313322-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
132b180f06 mm/rmap: simplify PageAnonExclusive sanity checks when adding anon rmap 
Let's sanity-check PageAnonExclusive vs.  mapcount in page_add_anon_rmap()
and hugepage_add_anon_rmap() after setting PageAnonExclusive simply by
re-reading the mapcounts.

We can stop initializing the "first" variable in page_add_anon_rmap() and
no longer need an atomic_inc_and_test() in hugepage_add_anon_rmap().

While at it, switch to VM_WARN_ON_FOLIO().

[david@redhat.com: update check for doubly-mapped page]
  Link: https://lkml.kernel.org/r/d8e5a093-2e22-c14b-7e64-6da280398d9f@redhat.com
Link: https://lkml.kernel.org/r/20230913125113.313322-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
a1f34ee1de mm/rmap: warn on new PTE-mapped folios in page_add_anon_rmap() 
If swapin code would ever decide to not use order-0 pages and supply a
PTE-mapped large folio, we will have to change how we call
__folio_set_anon() -- eventually with exclusive=false and an adjusted
address.  For now, let's add a VM_WARN_ON_FOLIO() with a comment about the
situation.

Link: https://lkml.kernel.org/r/20230913125113.313322-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
c5c5400347 mm/rmap: move folio_test_anon() check out of __folio_set_anon() 
Let's handle it in the caller; no need for the "first" check based on the
mapcount.

We really only end up with !anon pages in page_add_anon_rmap() via
do_swap_page(), where we hold the folio lock.  So races are not possible. 
Add a VM_WARN_ON_FOLIO() to make sure that we really hold the folio lock.

In the future, we might want to let do_swap_page() use
folio_add_new_anon_rmap() on new pages instead: however, we might have to
pass then whether the folio is exclusive or not.  So keep it in there for
now.

For hugetlb we never expect to have a non-anon page in
hugepage_add_anon_rmap().  Remove that code, along with some other checks
that are either not required or were checked in
hugepage_add_new_anon_rmap() already.

Link: https://lkml.kernel.org/r/20230913125113.313322-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
c66db8c070 mm/rmap: move SetPageAnonExclusive out of __page_set_anon_rmap() 
Let's handle it in the caller.  No need to pass the page.  While at it,
rename the function to __folio_set_anon() and pass "bool exclusive"
instead of "int exclusive".

Link: https://lkml.kernel.org/r/20230913125113.313322-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
David Hildenbrand
fd63908706 mm/rmap: drop stale comment in page_add_anon_rmap and hugepage_add_anon_rmap() 
Patch series "Anon rmap cleanups".

Some cleanups around rmap for anon pages.  I'm working on more cleanups
also around file rmap -- also to handle the "compound" parameter
internally only and to let hugetlb use page_add_file_rmap(), but these
changes make sense separately.


This patch (of 6):

That comment was added in commit 5dbe0af47f ("mm: fix kernel BUG at
mm/rmap.c:1017!") to document why we can see vma->vm_end getting adjusted
concurrently due to a VMA split.

However, the optimized locking code was changed again in bf181b9f9d ("mm
anon rmap: replace same_anon_vma linked list with an interval tree.").

...  and later, the comment was changed in commit 0503ea8f5b ("mm/mmap:
remove __vma_adjust()") to talk about "vma_merge" although the original
issue was with VMA splitting.

Let's just remove that comment.  Nowadays, it's outdated, imprecise and
confusing.

Link: https://lkml.kernel.org/r/20230913125113.313322-1-david@redhat.com
Link: https://lkml.kernel.org/r/20230913125113.313322-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
Xin Hao
811244a501 mm: memcg: add THP swap out info for anonymous reclaim 
At present, we support per-memcg reclaim strategy, however we do not know
the number of transparent huge pages being reclaimed, as we know the
transparent huge pages need to be splited before reclaim them, and they
will bring some performance bottleneck effect.  for example, when two
memcg (A & B) are doing reclaim for anonymous pages at same time, and 'A'
memcg is reclaiming a large number of transparent huge pages, we can
better analyze that the performance bottleneck will be caused by 'A'
memcg.  therefore, in order to better analyze such problems, there add THP
swap out info for per-memcg.

[akpm@linux-foundation.orgL fix swap_writepage_fs(), per Johannes]
  Link: https://lkml.kernel.org/r/20230913213343.GB48476@cmpxchg.org
Link: https://lkml.kernel.org/r/20230913164938.16918-1-vernhao@tencent.com
Signed-off-by: Xin Hao <vernhao@tencent.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
liujinlong
ed547ab6f4 mm: vmscan: modify an easily misunderstood function name 
When looking at the code in the memory part, I found that the purpose of
the function prepare_scan_countis very different from the function name. 
It is easy to misunderstand when reading.The function prepare_scan_count
mainly completes the assignment of the scan_control structure.Therefore, I
suggest that the function name can be changed to prepare_scan_control,
which is easier to understand.

Link: https://lkml.kernel.org/r/20230912085923.27238-1-liujinlong@kylinos.cn
Signed-off-by: liujinlong <liujinlong@kylinos.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:27 -07:00
Qi Zheng
8a0e8bb112 mm: shrinker: convert shrinker_rwsem to mutex 
Now there are no readers of shrinker_rwsem, so we can simply replace it
with mutex lock.

[akpm@linux-foundation.org: update the fix to alloc_shrinker_info()]
Link: https://lkml.kernel.org/r/20230911094444.68966-46-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
604b8b6550 mm: shrinker: hold write lock to reparent shrinker nr_deferred 
For now, reparent_shrinker_deferred() is the only holder of read lock of
shrinker_rwsem. And it already holds the global cgroup_mutex, so it will
not be called in parallel.

Therefore, in order to convert shrinker_rwsem to shrinker_mutex later,
here we change to hold the write lock of shrinker_rwsem to reparent.

Link: https://lkml.kernel.org/r/20230911094444.68966-45-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
50d09da8e1 mm: shrinker: make memcg slab shrink lockless 
Like global slab shrink, this commit also uses refcount+RCU method to make
memcg slab shrink lockless.

Use the following script to do slab shrink stress test:

```

DIR="/root/shrinker/memcg/mnt"

do_create()
{
    mkdir -p /sys/fs/cgroup/memory/test
    echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
    for i in `seq 0 $1`;
    do
        mkdir -p /sys/fs/cgroup/memory/test/$i;
        echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
        mkdir -p $DIR/$i;
    done
}

do_mount()
{
    for i in `seq $1 $2`;
    do
        mount -t tmpfs $i $DIR/$i;
    done
}

do_touch()
{
    for i in `seq $1 $2`;
    do
        echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
        dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 &
    done
}

case "$1" in
  touch)
    do_touch $2 $3
    ;;
  test)
    do_create 4000
    do_mount 0 4000
    do_touch 0 3000
    ;;
  *)
    exit 1
    ;;
esac
```

Save the above script, then run test and touch commands. Then we can use
the following perf command to view hotspots:

perf top -U -F 999

1) Before applying this patchset:

  33.15%  [kernel]          [k] down_read_trylock
  25.38%  [kernel]          [k] shrink_slab
  21.75%  [kernel]          [k] up_read
   4.45%  [kernel]          [k] _find_next_bit
   2.27%  [kernel]          [k] do_shrink_slab
   1.80%  [kernel]          [k] intel_idle_irq
   1.79%  [kernel]          [k] shrink_lruvec
   0.67%  [kernel]          [k] xas_descend
   0.41%  [kernel]          [k] mem_cgroup_iter
   0.40%  [kernel]          [k] shrink_node
   0.38%  [kernel]          [k] list_lru_count_one

2) After applying this patchset:

  64.56%  [kernel]          [k] shrink_slab
  12.18%  [kernel]          [k] do_shrink_slab
   3.30%  [kernel]          [k] __rcu_read_unlock
   2.61%  [kernel]          [k] shrink_lruvec
   2.49%  [kernel]          [k] __rcu_read_lock
   1.93%  [kernel]          [k] intel_idle_irq
   0.89%  [kernel]          [k] shrink_node
   0.81%  [kernel]          [k] mem_cgroup_iter
   0.77%  [kernel]          [k] mem_cgroup_calculate_protection
   0.66%  [kernel]          [k] list_lru_count_one

We can see that the first perf hotspot becomes shrink_slab, which is what
we expect.

Link: https://lkml.kernel.org/r/20230911094444.68966-44-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
ca1d36b823 mm: shrinker: make global slab shrink lockless 
The shrinker_rwsem is a global read-write lock in shrinkers subsystem,
which protects most operations such as slab shrink, registration and
unregistration of shrinkers, etc. This can easily cause problems in the
following cases.

1) When the memory pressure is high and there are many filesystems
   mounted or unmounted at the same time, slab shrink will be affected
   (down_read_trylock() failed).

   Such as the real workload mentioned by Kirill Tkhai:

   ```
   One of the real workloads from my experience is start
   of an overcommitted node containing many starting
   containers after node crash (or many resuming containers
   after reboot for kernel update). In these cases memory
   pressure is huge, and the node goes round in long reclaim.
   ```

2) If a shrinker is blocked (such as the case mentioned
   in [1]) and a writer comes in (such as mount a fs),
   then this writer will be blocked and cause all
   subsequent shrinker-related operations to be blocked.

Even if there is no competitor when shrinking slab, there may still be a
problem. The down_read_trylock() may become a perf hotspot with frequent
calls to shrink_slab(). Because of the poor multicore scalability of
atomic operations, this can lead to a significant drop in IPC
(instructions per cycle).

We used to implement the lockless slab shrink with SRCU [2], but then
kernel test robot reported -88.8% regression in
stress-ng.ramfs.ops_per_sec test case [3], so we reverted it [4].

This commit uses the refcount+RCU method [5] proposed by Dave Chinner
to re-implement the lockless global slab shrink. The memcg slab shrink is
handled in the subsequent patch.

For now, all shrinker instances are converted to dynamically allocated and
will be freed by call_rcu(). So we can use rcu_read_{lock,unlock}() to
ensure that the shrinker instance is valid.

And the shrinker instance will not be run again after unregistration. So
the structure that records the pointer of shrinker instance can be safely
freed without waiting for the RCU read-side critical section.

In this way, while we implement the lockless slab shrink, we don't need to
be blocked in unregister_shrinker().

The following are the test results:

stress-ng --timeout 60 --times --verify --metrics-brief --ramfs 9 &

1) Before applying this patchset:

setting to a 60 second run per stressor
dispatching hogs: 9 ramfs
stressor       bogo ops real time  usr time  sys time   bogo ops/s     bogo ops/s
                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
ramfs            473062     60.00      8.00    279.13      7884.12        1647.59
for a 60.01s run time:
   1440.34s available CPU time
      7.99s user time   (  0.55%)
    279.13s system time ( 19.38%)
    287.12s total time  ( 19.93%)
load average: 7.12 2.99 1.15
successful run completed in 60.01s (1 min, 0.01 secs)

2) After applying this patchset:

setting to a 60 second run per stressor
dispatching hogs: 9 ramfs
stressor       bogo ops real time  usr time  sys time   bogo ops/s     bogo ops/s
                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
ramfs            477165     60.00      8.13    281.34      7952.55        1648.40
for a 60.01s run time:
   1440.33s available CPU time
      8.12s user time   (  0.56%)
    281.34s system time ( 19.53%)
    289.46s total time  ( 20.10%)
load average: 6.98 3.03 1.19
successful run completed in 60.01s (1 min, 0.01 secs)

We can see that the ops/s has hardly changed.

[1]. https://lore.kernel.org/lkml/20191129214541.3110-1-ptikhomirov@virtuozzo.com/
[2]. https://lore.kernel.org/lkml/20230313112819.38938-1-zhengqi.arch@bytedance.com/
[3]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/
[4]. https://lore.kernel.org/all/20230609081518.3039120-1-qi.zheng@linux.dev/
[5]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/

Link: https://lkml.kernel.org/r/20230911094444.68966-43-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
48a7a0996a mm: shrinker: rename {prealloc|unregister}_memcg_shrinker() to shrinker_memcg_{alloc|remove}() 
With the new shrinker APIs, there is no action such as prealloc, so rename
{prealloc|unregister}_memcg_shrinker() to shrinker_memcg_{alloc|remove}(),
which corresponds to the idr_{alloc|remove}() inside the function.

Link: https://lkml.kernel.org/r/20230911094444.68966-42-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
307bececcd mm: shrinker: add a secondary array for shrinker_info::{map, nr_deferred} 
Currently, we maintain two linear arrays per node per memcg, which are
shrinker_info::map and shrinker_info::nr_deferred. And we need to resize
them when the shrinker_nr_max is exceeded, that is, allocate a new array,
and then copy the old array to the new array, and finally free the old
array by RCU.

For shrinker_info::map, we do set_bit() under the RCU lock, so we may set
the value into the old map which is about to be freed. This may cause the
value set to be lost. The current solution is not to copy the old map when
resizing, but to set all the corresponding bits in the new map to 1. This
solves the data loss problem, but bring the overhead of more pointless
loops while doing memcg slab shrink.

For shrinker_info::nr_deferred, we will only modify it under the read lock
of shrinker_rwsem, so it will not run concurrently with the resizing. But
after we make memcg slab shrink lockless, there will be the same data loss
problem as shrinker_info::map, and we can't work around it like the map.

For such resizable arrays, the most straightforward idea is to change it
to xarray, like we did for list_lru [1]. We need to do xa_store() in the
list_lru_add()-->set_shrinker_bit(), but this will cause memory
allocation, and the list_lru_add() doesn't accept failure. A possible
solution is to pre-allocate, but the location of pre-allocation is not
well determined (such as deferred_split_shrinker case).

Therefore, this commit chooses to introduce the following secondary array
for shrinker_info::{map, nr_deferred}:

+---------------+--------+--------+-----+
| shrinker_info | unit 0 | unit 1 | ... | (secondary array)
+---------------+--------+--------+-----+
                     |
                     v
                +---------------+-----+
                | nr_deferred[] | map | (leaf array)
                +---------------+-----+
                (shrinker_info_unit)

The leaf array is never freed unless the memcg is destroyed. The secondary
array will be resized every time the shrinker id exceeds shrinker_nr_max.
So the shrinker_info_unit can be indexed from both the old and the new
shrinker_info->unit[x]. Then even if we get the old secondary array under
the RCU lock, the found map and nr_deferred are also true, so the updated
nr_deferred and map will not be lost.

[1]. https://lore.kernel.org/all/20220228122126.37293-13-songmuchun@bytedance.com/

[zhengqi.arch@bytedance.com: unlock the &shrinker_rwsem before the call to free_shrinker_info()]
  Link: https://lkml.kernel.org/r/20230928141517.12164-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20230911094444.68966-41-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
f2383e0150 mm: shrinker: remove old APIs 
Now no users are using the old APIs, just remove them.

Link: https://lkml.kernel.org/r/20230911094444.68966-40-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
c19b548b49 zsmalloc: dynamically allocate the mm-zspool shrinker 
In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the mm-zspool shrinker, so that it can be freed
asynchronously via RCU. Then it doesn't need to wait for RCU read-side
critical section when releasing the struct zs_pool.

Link: https://lkml.kernel.org/r/20230911094444.68966-38-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:26 -07:00
Qi Zheng
219c666eb2 mm: workingset: dynamically allocate the mm-shadow shrinker 
Use new APIs to dynamically allocate the mm-shadow shrinker.

Link: https://lkml.kernel.org/r/20230911094444.68966-20-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:24 -07:00
Qi Zheng
54d917295b mm: thp: dynamically allocate the thp-related shrinkers 
Use new APIs to dynamically allocate the thp-zero and thp-deferred_split
shrinkers.

Link: https://lkml.kernel.org/r/20230911094444.68966-18-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:24 -07:00
Qi Zheng
c42d50aefd mm: shrinker: add infrastructure for dynamically allocating shrinker 
Patch series "use refcount+RCU method to implement lockless slab shrink",
v6.

1. Background
=============

We used to implement the lockless slab shrink with SRCU [1], but then kernel
test robot reported -88.8% regression in stress-ng.ramfs.ops_per_sec test
case [2], so we reverted it [3].

This patch series aims to re-implement the lockless slab shrink using the
refcount+RCU method proposed by Dave Chinner [4].

[1]. https://lore.kernel.org/lkml/20230313112819.38938-1-zhengqi.arch@bytedance.com/
[2]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/
[3]. https://lore.kernel.org/all/20230609081518.3039120-1-qi.zheng@linux.dev/
[4]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/

2. Implementation
=================

Currently, the shrinker instances can be divided into the following three types:

a) global shrinker instance statically defined in the kernel, such as
   workingset_shadow_shrinker.

b) global shrinker instance statically defined in the kernel modules, such as
   mmu_shrinker in x86.

c) shrinker instance embedded in other structures.

For case a, the memory of shrinker instance is never freed. For case b, the
memory of shrinker instance will be freed after synchronize_rcu() when the
module is unloaded. For case c, the memory of shrinker instance will be freed
along with the structure it is embedded in.

In preparation for implementing lockless slab shrink, we need to dynamically
allocate those shrinker instances in case c, then the memory can be dynamically
freed alone by calling kfree_rcu().

This patchset adds the following new APIs for dynamically allocating shrinker,
and add a private_data field to struct shrinker to record and get the original
embedded structure.

1. shrinker_alloc()
2. shrinker_register()
3. shrinker_free()

In order to simplify shrinker-related APIs and make shrinker more independent of
other kernel mechanisms, this patchset uses the above APIs to convert all
shrinkers (including case a and b) to dynamically allocated, and then remove all
existing APIs. This will also have another advantage mentioned by Dave Chinner:

```
The other advantage of this is that it will break all the existing out of tree
code and third party modules using the old API and will no longer work with a
kernel using lockless slab shrinkers. They need to break (both at the source and
binary levels) to stop bad things from happening due to using uncoverted
shrinkers in the new setup.
```

Then we free the shrinker by calling call_rcu(), and use rcu_read_{lock,unlock}()
to ensure that the shrinker instance is valid. And the shrinker::refcount
mechanism ensures that the shrinker instance will not be run again after
unregistration. So the structure that records the pointer of shrinker instance
can be safely freed without waiting for the RCU read-side critical section.

In this way, while we implement the lockless slab shrink, we don't need to be
blocked in unregister_shrinker() to wait RCU read-side critical section.

PATCH 1: introduce new APIs
PATCH 2~38: convert all shrinnkers to use new APIs
PATCH 39: remove old APIs
PATCH 40~41: some cleanups and preparations
PATCH 42-43: implement the lockless slab shrink
PATCH 44~45: convert shrinker_rwsem to mutex

3. Testing
==========

3.1 slab shrink stress test
---------------------------

We can reproduce the down_read_trylock() hotspot through the following script:

```

DIR="/root/shrinker/memcg/mnt"

do_create()
{
    mkdir -p /sys/fs/cgroup/memory/test
    echo 4G > /sys/fs/cgroup/memory/test/memory.limit_in_bytes
    for i in `seq 0 $1`;
    do
        mkdir -p /sys/fs/cgroup/memory/test/$i;
        echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
        mkdir -p $DIR/$i;
    done
}

do_mount()
{
    for i in `seq $1 $2`;
    do
        mount -t tmpfs $i $DIR/$i;
    done
}

do_touch()
{
    for i in `seq $1 $2`;
    do
        echo $$ > /sys/fs/cgroup/memory/test/$i/cgroup.procs;
        dd if=/dev/zero of=$DIR/$i/file$i bs=1M count=1 &
    done
}

case "$1" in
  touch)
    do_touch $2 $3
    ;;
  test)
    do_create 4000
    do_mount 0 4000
    do_touch 0 3000
    ;;
  *)
    exit 1
    ;;
esac
```

Save the above script, then run test and touch commands. Then we can use the
following perf command to view hotspots:

perf top -U -F 999

1) Before applying this patchset:

  33.15%  [kernel]          [k] down_read_trylock
  25.38%  [kernel]          [k] shrink_slab
  21.75%  [kernel]          [k] up_read
   4.45%  [kernel]          [k] _find_next_bit
   2.27%  [kernel]          [k] do_shrink_slab
   1.80%  [kernel]          [k] intel_idle_irq
   1.79%  [kernel]          [k] shrink_lruvec
   0.67%  [kernel]          [k] xas_descend
   0.41%  [kernel]          [k] mem_cgroup_iter
   0.40%  [kernel]          [k] shrink_node
   0.38%  [kernel]          [k] list_lru_count_one

2) After applying this patchset:

  64.56%  [kernel]          [k] shrink_slab
  12.18%  [kernel]          [k] do_shrink_slab
   3.30%  [kernel]          [k] __rcu_read_unlock
   2.61%  [kernel]          [k] shrink_lruvec
   2.49%  [kernel]          [k] __rcu_read_lock
   1.93%  [kernel]          [k] intel_idle_irq
   0.89%  [kernel]          [k] shrink_node
   0.81%  [kernel]          [k] mem_cgroup_iter
   0.77%  [kernel]          [k] mem_cgroup_calculate_protection
   0.66%  [kernel]          [k] list_lru_count_one

We can see that the first perf hotspot becomes shrink_slab, which is what we
expect.

3.2 registration and unregistration stress test
-----------------------------------------------

Run the command below to test:

stress-ng --timeout 60 --times --verify --metrics-brief --ramfs 9 &

1) Before applying this patchset:

setting to a 60 second run per stressor
dispatching hogs: 9 ramfs
stressor       bogo ops real time  usr time  sys time   bogo ops/s     bogo ops/s
                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
ramfs            473062     60.00      8.00    279.13      7884.12        1647.59
for a 60.01s run time:
   1440.34s available CPU time
      7.99s user time   (  0.55%)
    279.13s system time ( 19.38%)
    287.12s total time  ( 19.93%)
load average: 7.12 2.99 1.15
successful run completed in 60.01s (1 min, 0.01 secs)

2) After applying this patchset:

setting to a 60 second run per stressor
dispatching hogs: 9 ramfs
stressor       bogo ops real time  usr time  sys time   bogo ops/s     bogo ops/s
                          (secs)    (secs)    (secs)   (real time) (usr+sys time)
ramfs            477165     60.00      8.13    281.34      7952.55        1648.40
for a 60.01s run time:
   1440.33s available CPU time
      8.12s user time   (  0.56%)
    281.34s system time ( 19.53%)
    289.46s total time  ( 20.10%)
load average: 6.98 3.03 1.19
successful run completed in 60.01s (1 min, 0.01 secs)

We can see that the ops/s has hardly changed.


This patch (of 45):

Currently, the shrinker instances can be divided into the following three
types:

a) global shrinker instance statically defined in the kernel, such as
   workingset_shadow_shrinker.

b) global shrinker instance statically defined in the kernel modules, such
   as mmu_shrinker in x86.

c) shrinker instance embedded in other structures.

For case a, the memory of shrinker instance is never freed. For case b,
the memory of shrinker instance will be freed after synchronize_rcu() when
the module is unloaded. For case c, the memory of shrinker instance will
be freed along with the structure it is embedded in.

In preparation for implementing lockless slab shrink, we need to
dynamically allocate those shrinker instances in case c, then the memory
can be dynamically freed alone by calling kfree_rcu().

So this commit adds the following new APIs for dynamically allocating
shrinker, and add a private_data field to struct shrinker to record and
get the original embedded structure.

1. shrinker_alloc()

Used to allocate shrinker instance itself and related memory, it will
return a pointer to the shrinker instance on success and NULL on failure.

2. shrinker_register()

Used to register the shrinker instance, which is same as the current
register_shrinker_prepared().

3. shrinker_free()

Used to unregister (if needed) and free the shrinker instance.

In order to simplify shrinker-related APIs and make shrinker more
independent of other kernel mechanisms, subsequent submissions will use
the above API to convert all shrinkers (including case a and b) to
dynamically allocated, and then remove all existing APIs.

This will also have another advantage mentioned by Dave Chinner:

```
The other advantage of this is that it will break all the existing
out of tree code and third party modules using the old API and will
no longer work with a kernel using lockless slab shrinkers. They
need to break (both at the source and binary levels) to stop bad
things from happening due to using unconverted shrinkers in the new
setup.
```

[zhengqi.arch@bytedance.com: mm: shrinker: some cleanup]
  Link: https://lkml.kernel.org/r/20230919024607.65463-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20230911094444.68966-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20230911094444.68966-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <cel@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:23 -07:00
Qi Zheng
0b2f5ea1aa drm/ttm: introduce pool_shrink_rwsem 
Currently, synchronize_shrinkers() is only used by TTM pool.  It only
requires that no shrinkers run in parallel.

After we use RCU+refcount method to implement the lockless slab shrink, we
can not use shrinker_rwsem or synchronize_rcu() to guarantee that all
shrinker invocations have seen an update before freeing memory.

So we introduce a new pool_shrink_rwsem to implement a private
ttm_pool_synchronize_shrinkers(), so as to achieve the same purpose.

Link: https://lkml.kernel.org/r/20230911092517.64141-5-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Chuck Lever <cel@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:23 -07:00
Qi Zheng
1dd49e58f9 mm: shrinker: remove redundant shrinker_rwsem in debugfs operations 
debugfs_remove_recursive() will wait for debugfs_file_put() to return, so
the shrinker will not be freed when doing debugfs operations (such as
shrinker_debugfs_count_show() and shrinker_debugfs_scan_write()), so there
is no need to hold shrinker_rwsem during debugfs operations.

Link: https://lkml.kernel.org/r/20230911092517.64141-4-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:23 -07:00
Qi Zheng
96f7b2b9bb mm: vmscan: move shrinker-related code into a separate file 
The mm/vmscan.c file is too large, so separate the shrinker-related code
from it into a separate file.  No functional changes.

Link: https://lkml.kernel.org/r/20230911092517.64141-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:23 -07:00
Qi Zheng
3ee0aa9f06 mm: move some shrinker-related function declarations to mm/internal.h 
Patch series "cleanups for lockless slab shrink", v4.

This series is some cleanups for lockless slab shrink.


This patch (of 4):

The following functions are only used inside the mm subsystem, so it's
better to move their declarations to the mm/internal.h file.

1. shrinker_debugfs_add()
2. shrinker_debugfs_detach()
3. shrinker_debugfs_remove()

Link: https://lkml.kernel.org/r/20230911092517.64141-1-zhengqi.arch@bytedance.com
Link: https://lkml.kernel.org/r/20230911092517.64141-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Alexander Potapenko
46fa84a2b9 kmsan: introduce test_memcpy_initialized_gap() 
Add a regression test for the special case where memcpy() previously
failed to correctly set the origins: if upon memcpy() four aligned
initialized bytes with a zero origin value ended up split between two
aligned four-byte chunks, one of those chunks could've received the zero
origin value even despite it contained uninitialized bytes from other
writes.

Link: https://lkml.kernel.org/r/20230911145702.2663753-4-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Alexander Potapenko
c3ab4873c8 kmsan: merge test_memcpy_aligned_to_unaligned{,2}() together 
Introduce report_reset() that allows checking for more than one KMSAN
report per testcase.

Fold test_memcpy_aligned_to_unaligned2() into
test_memcpy_aligned_to_unaligned(), so that they share the setup phase and
check the behavior of a single memcpy() call.

Link: https://lkml.kernel.org/r/20230911145702.2663753-3-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Alexander Potapenko
0be7b2c232 kmsan: prevent optimizations in memcpy tests 
Clang 18 learned to optimize away memcpy() calls of small uninitialized
scalar values.  To ensure that memcpy tests in kmsan_test.c still perform
calls to memcpy() (which KMSAN replaces with __msan_memcpy()), declare a
separate memcpy_noinline() function with volatile parameters, which won't
be optimized.

Also retire DO_NOT_OPTIMIZE(), as memcpy_noinline() is apparently enough.

Link: https://lkml.kernel.org/r/20230911145702.2663753-2-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Alexander Potapenko
be1ab60eb0 kmsan: simplify kmsan_internal_memmove_metadata() 
kmsan_internal_memmove_metadata() is the function that implements copying
metadata every time memcpy()/memmove() is called.  Because shadow memory
stores 1 byte per each byte of kernel memory, copying the shadow is
trivial and can be done by a single memmove() call.

Origins, on the other hand, are stored as 4-byte values corresponding to
every aligned 4 bytes of kernel memory.  Therefore, if either the source
or the destination of kmsan_internal_memmove_metadata() is unaligned, the
number of origin slots corresponding to the source or destination may
differ:

  1) memcpy(0xffff888080a00000, 0xffff888080900000, 4)
     copies 1 origin slot into 1 origin slot:

     src (0xffff888080900000): xxxx
     src origins:              o111
     dst (0xffff888080a00000): xxxx
     dst origins:              o111

  2) memcpy(0xffff888080a00001, 0xffff888080900000, 4)
     copies 1 origin slot into 2 origin slots:

     src (0xffff888080900000): xxxx
     src origins:              o111
     dst (0xffff888080a00000): .xxx x...
     dst origins:              o111 o111

  3) memcpy(0xffff888080a00000, 0xffff888080900001, 4)
     copies 2 origin slots into 1 origin slot:

     src (0xffff888080900000): .xxx x...
     src origins:              o111 o222
     dst (0xffff888080a00000): xxxx
     dst origins:              o111
                           (or o222)

Previously, kmsan_internal_memmove_metadata() tried to solve this problem
by copying min(src_slots, dst_slots) as is and cloning the missing slot on
one of the ends, if needed.

This was error-prone even in the simple cases where 4 bytes were copied,
and did not account for situations where the total number of nonzero
origin slots could have increased by more than one after copying:

  memcpy(0xffff888080a00000, 0xffff888080900002, 8)

  src (0xffff888080900002): ..xx .... xx..
  src origins:              o111 0000 o222
  dst (0xffff888080a00000): xx.. ..xx
                            o111 0000
                        (or 0000 o222)

The new implementation simply copies the shadow byte by byte, and updates
the corresponding origin slot, if the shadow byte is nonzero.  This
approach can handle complex cases with mixed initialized and uninitialized
bytes.  Similarly to KMSAN inline instrumentation, latter writes to bytes
sharing the same origin slots take precedence.

Link: https://lkml.kernel.org/r/20230911145702.2663753-1-glider@google.com
Fixes: f80be4571b ("kmsan: add KMSAN runtime core")
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Aleksa Sarai
1717449b44 memfd: drop warning for missing exec-related flags 
Commit 434ed3350f ("memfd: improve userspace warnings for missing
exec-related flags") attempted to make these warnings more useful (so
they would work as an incentive to get users to switch to specifying
these flags -- as intended by the original MFD_NOEXEC_SEAL patchset).
Unfortunately, it turns out that even INFO-level logging is too extreme
to enable by default and alternative solutions to the spam issue (such
as doing more extreme rate-limiting per-task) are either too ugly or
overkill for something as simple as emitting a log as a developer aid.

Given that the flags are new and there is no harm to not specifying them
(after all, we maintain backwards compatibility) we can just drop the
warnings for now until some time in the future when most programs have
migrated and distributions start using vm.memfd_noexec=1 (where failing
to pass the flag would result in unexpected errors for programs that use
executable memfds).

Link: https://lkml.kernel.org/r/20230912-memfd-reduce-spam-v2-1-7d92a4964b6a@cyphar.com
Fixes: 434ed3350f ("memfd: improve userspace warnings for missing exec-related flags")
Fixes: 2562d67b1b ("revert "memfd: improve userspace warnings for missing exec-related flags".")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Reported-by: Damian Tometzki <dtometzki@fedoraproject.org>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Ying Sun
84e8e54e2e mm/shmem: remove dead code can not be satisfied by "(CONFIG_SHMEM)&&(!(CONFIG_SHMEM))" 
The value of “.fs_flags” in line 4608 is a dead code which will never
be implemented，because its conditions of line 47 "#ifdef CONFIG_SHMEM"
and line 4607 are mutually exclusive.  It is recommended to delete
redundant code.

Link: https://lkml.kernel.org/r/20230906045012.14999-1-sunying@nj.iscas.ac.cn
Signed-off-by: Ying Sun <sunying@nj.iscas.ac.cn>
Suggested-by: Yanjie Ren <renyanjie01@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Angus Chen
037dd8f902 mm/vmscan: print err before panic 
If panic is enable,the err information will not be printed before bugon,
So swap it.  Print the return value of PTR_ERR(pgdat->kswapd) also.

Link: https://lkml.kernel.org/r/20230906083700.181-1-angus.chen@jaguarmicro.com
Signed-off-by: Angus Chen <angus.chen@jaguarmicro.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Yajun Deng
40dca9b3d6 mm/mm_init.c: remove redundant pr_info when node is memoryless 
There is a similar pr_info in free_area_init_node(), so remove the
redundant pr_info.

before:
[    0.006314] Initializing node 0 as memoryless
[    0.006445] Initmem setup node 0 as memoryless
[    0.006450] Initmem setup node 1 [mem 0x0000000000001000-0x000000003fffffff]
[    0.006453] Initmem setup node 2 [mem 0x0000000040000000-0x000000007ffd7fff]
[    0.006454] Initializing node 3 as memoryless
[    0.006584] Initmem setup node 3 as memoryless
[    0.006585] Initmem setup node 4 [mem 0x0000000100000000-0x00000001bfffffff]
[    0.006586] Initmem setup node 5 [mem 0x00000001c0000000-0x00000001ffffffff]
[    0.006587] Initmem setup node 6 [mem 0x0000000200000000-0x000000023fffffff]

after:
[    0.004147] Initmem setup node 0 as memoryless
[    0.004148] Initmem setup node 1 [mem 0x0000000000001000-0x000000003fffffff]
[    0.004150] Initmem setup node 2 [mem 0x0000000040000000-0x000000007ffd7fff]
[    0.004154] Initmem setup node 3 as memoryless
[    0.004155] Initmem setup node 4 [mem 0x0000000100000000-0x00000001bfffffff]
[    0.004156] Initmem setup node 5 [mem 0x00000001c0000000-0x00000001ffffffff]
[    0.004157] Initmem setup node 6 [mem 0x0000000200000000-0x000000023fffffff]

Link: https://lkml.kernel.org/r/20230906091113.4029983-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Yuan Can
6a898c2757 mm: hugetlb_vmemmap: allow alloc vmemmap pages fallback to other nodes 
In vmemmap_remap_free(), a new head vmemmap page is allocated to avoid
breaking a contiguous block of struct page memory, however, the allocation
can always fail when the given node is movable node.  Remove the
__GFP_THISNODE to help avoid fragmentation.

Link: https://lkml.kernel.org/r/20230906093157.9737-1-yuancan@huawei.com
Signed-off-by: Yuan Can <yuancan@huawei.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:22 -07:00
Xiu Jianfeng
7fa38d0ea0 mm: remove duplicated vma->vm_flags check when expanding stack 
expand_upwards() and expand_downwards() will return -EFAULT if VM_GROWSUP
or VM_GROWSDOWN is not correctly set in vma->vm_flags, however in
!CONFIG_STACK_GROWSUP case, expand_stack_locked() returns -EINVAL first if
!(vma->vm_flags & VM_GROWSDOWN) before calling expand_downwards(), to keep
the consistency with CONFIG_STACK_GROWSUP case, remove this check.

The usages of this function are as below:

A:fs/exec.c
ret = expand_stack_locked(vma, stack_base);
if (ret)
	ret = -EFAULT;

or

B:mm/memory.c mm/mmap.c
if (expand_stack_locked(vma, addr))
	return NULL;

which means the return value will not propagate to other places, so I
believe there is no user-visible effects of this change, and it's
unnecessary to backport to earlier versions.

Link: https://lkml.kernel.org/r/20230906103312.645712-1-xiujianfeng@huaweicloud.com
Fixes: f440fa1ac9 ("mm: make find_extend_vma() fail if write lock not held")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:21 -07:00
SeongJae Park
2d00946bd7 mm/damon/core: remove 'struct target *' parameter from damon_aggregated tracepoint 
damon_aggregateed tracepoint is receiving 'struct target *', but doesn't
use it.  Remove it from the prototype.

Link: https://lkml.kernel.org/r/20230907022929.91361-12-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:21 -07:00
SeongJae Park
27e68c4b0d mm/damon/core: fix a comment about damon_set_attrs() call timings 
The comment on damon_set_attrs() says it should not be called while the
kdamond is running, but now some DAMON modules like sysfs interface and
DAMON_RECLAIM call it from after_aggregation() and/or
after_wmarks_check() callbacks for online tuning.  Update the comment.

Link: https://lkml.kernel.org/r/20230907022929.91361-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:21 -07:00
Nhat Pham
64d4d49c5f zswap: change zswap's default allocator to zsmalloc 
Out of zswap's 3 allocators, zsmalloc is the clear superior in terms of
memory utilization, both in theory and as observed in practice, with its
high storage density and low internal fragmentation.  zsmalloc is also
more actively developed and maintained, since it is the allocator of
choice for zswap for many users, as well as the only allocator for zram.

A historical objection to the selection of zsmalloc as the default
allocator for zswap is its lack of writeback capability.  However, this
has changed, with the zsmalloc writeback patchset, and the subsequent
zswap LRU refactor.  With this, there is not a lot of good reasons to keep
zbud, an otherwise inferior allocator, as the default instead of zswap.

This patch changes the default allocator to zsmalloc.  The only exception
is on settings without MMU, in which case zbud will remain as the default.

Link: https://lkml.kernel.org/r/20230908235115.2943486-1-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Joel Fernandes (Google)
b1e5a3dee2 mm/mremap: allow moves within the same VMA for stack moves 
For the stack move happening in shift_arg_pages(), the move is happening
within the same VMA which spans the old and new ranges.

In case the aligned address happens to fall within that VMA, allow such
moves and don't abort the mremap alignment optimization.

In the regular non-stack mremap case, we cannot allow any such moves as
will end up destroying some part of the mapping (either the source of the
move, or part of the existing mapping).  So just avoid it for stack moves.

Link: https://lkml.kernel.org/r/20230903151328.2981432-3-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Joel Fernandes (Google)
af8ca1c149 mm/mremap: optimize the start addresses in move_page_tables() 
Patch series "Optimize mremap during mutual alignment within PMD", v6.

This patchset optimizes the start addresses in move_page_tables() and
tests the changes.  It addresses a warning [1] that occurs due to a
downward, overlapping move on a mutually-aligned offset within a PMD
during exec.  By initiating the copy process at the PMD level when such
alignment is present, we can prevent this warning and speed up the copying
process at the same time.  Linus Torvalds suggested this idea.  Check the
individual patches for more details.  [1]
https://lore.kernel.org/all/ZB2GTBD%2FLWTrkOiO@dhcp22.suse.cz/


This patch (of 7):

Recently, we see reports [1] of a warning that triggers due to
move_page_tables() doing a downward and overlapping move on a
mutually-aligned offset within a PMD.  By mutual alignment, I mean the
source and destination addresses of the mremap are at the same offset
within a PMD.

This mutual alignment along with the fact that the move is downward is
sufficient to cause a warning related to having an allocated PMD that does
not have PTEs in it.

This warning will only trigger when there is mutual alignment in the move
operation.  A solution, as suggested by Linus Torvalds [2], is to initiate
the copy process at the PMD level whenever such alignment is present. 
Implementing this approach will not only prevent the warning from being
triggered, but it will also optimize the operation as this method should
enhance the speed of the copy process whenever there's a possibility to
start copying at the PMD level.

Some more points:
a. The optimization can be done only when both the source and
destination of the mremap do not have anything mapped below it up to a
PMD boundary. I add support to detect that.

b. #1 is not a problem for the call to move_page_tables() from exec.c as
nothing is expected to be mapped below the source. However, for
non-overlapping mutually aligned moves as triggered by mremap(2), I
added support for checking such cases.

c. I currently only optimize for PMD moves, in the future I/we can build
on this work and do PUD moves as well if there is a need for this. But I
want to take it one step at a time.

d. We need to be careful about mremap of ranges within the VMA itself.
For this purpose, I added checks to determine if the address after
alignment falls within its VMA itself.

[1] https://lore.kernel.org/all/ZB2GTBD%2FLWTrkOiO@dhcp22.suse.cz/
[2] https://lore.kernel.org/all/CAHk-=whd7msp8reJPfeGNyt0LiySMT0egExx3TVZSX3Ok6X=9g@mail.gmail.com/

Link: https://lkml.kernel.org/r/20230903151328.2981432-1-joel@joelfernandes.org
Link: https://lkml.kernel.org/r/20230903151328.2981432-2-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Yuan Can
2eaa6c2abb mm: hugetlb_vmemmap: fix hugetlb page number decrease failed on movable nodes 
The decreasing of hugetlb pages number failed with the following message
given:

 sh: page allocation failure: order:0, mode:0x204cc0(GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_THISNODE)
 CPU: 1 PID: 112 Comm: sh Not tainted 6.5.0-rc7-... #45
 Hardware name: linux,dummy-virt (DT)
 Call trace:
  dump_backtrace.part.6+0x84/0xe4
  show_stack+0x18/0x24
  dump_stack_lvl+0x48/0x60
  dump_stack+0x18/0x24
  warn_alloc+0x100/0x1bc
  __alloc_pages_slowpath.constprop.107+0xa40/0xad8
  __alloc_pages+0x244/0x2d0
  hugetlb_vmemmap_restore+0x104/0x1e4
  __update_and_free_hugetlb_folio+0x44/0x1f4
  update_and_free_hugetlb_folio+0x20/0x68
  update_and_free_pages_bulk+0x4c/0xac
  set_max_huge_pages+0x198/0x334
  nr_hugepages_store_common+0x118/0x178
  nr_hugepages_store+0x18/0x24
  kobj_attr_store+0x18/0x2c
  sysfs_kf_write+0x40/0x54
  kernfs_fop_write_iter+0x164/0x1dc
  vfs_write+0x3a8/0x460
  ksys_write+0x6c/0x100
  __arm64_sys_write+0x1c/0x28
  invoke_syscall+0x44/0x100
  el0_svc_common.constprop.1+0x6c/0xe4
  do_el0_svc+0x38/0x94
  el0_svc+0x28/0x74
  el0t_64_sync_handler+0xa0/0xc4
  el0t_64_sync+0x174/0x178
 Mem-Info:
  ...

The reason is that the hugetlb pages being released are allocated from
movable nodes, and with hugetlb_optimize_vmemmap enabled, vmemmap pages
need to be allocated from the same node during the hugetlb pages
releasing. With GFP_KERNEL and __GFP_THISNODE set, allocating from movable
node is always failed. Fix this problem by removing __GFP_THISNODE.

Link: https://lkml.kernel.org/r/20230905124503.24899-1-yuancan@huawei.com
Fixes: ad2fa3717b ("mm: hugetlb: alloc the vmemmap pages associated with each HugeTLB page")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Uros Bizjak
77cd814835 mm/vmstat: use this_cpu_try_cmpxchg in mod_{zone,node}_state 
Use this_cpu_try_cmpxchg instead of this_cpu_cmpxchg (*ptr, old, new) ==
old in mod_zone_state and mod_node_state.  x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg (and
related move instruction in front of cmpxchg).

Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails.  There is no need to re-read the value in the loop.

No functional change intended.

Link: https://lkml.kernel.org/r/20230904150917.8318-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Matthew Wilcox (Oracle)
91e79d22be mm: convert DAX lock/unlock page to lock/unlock folio 
The one caller of DAX lock/unlock page already calls compound_head(), so
use page_folio() instead, then use a folio throughout the DAX code to
remove uses of page->mapping and page->index.

[jane.chu@oracle.com: add comment to mf_generic_kill_procss(), simplify mf_generic_kill_procs:folio initialization]
  Link: https://lkml.kernel.org/r/20230908222336.186313-1-jane.chu@oracle.com
Link: https://lkml.kernel.org/r/20230822231314.349200-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Jane Chu <jane.chu@oracle.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Mateusz Guzik
bc0c335760 mm: remove remnants of SPLIT_RSS_COUNTING 
The feature got retired in f1a7941243 ("mm: convert mm's rss stats into
percpu_counter"), but the patch failed to fully clean it up.

Link: https://lkml.kernel.org/r/20230823170556.2281747-1-mjguzik@gmail.com
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:20 -07:00
Vern Hao
97144ce008 mm/vmscan: use folio_migratetype() instead of get_pageblock_migratetype() 
In skip_cma(), we can use folio_migratetype() to replace
get_pageblock_migratetype().

Link: https://lkml.kernel.org/r/20230825075735.52436-1-user@VERNHAO-MC1
Signed-off-by: Vern Hao <vernhao@tencent.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Lorenzo Stoakes
80e4a765a7 mm: refactor si_mem_available() 
si_mem_available() needlessly places LRU statistics into an array before
retrieving only two of them, simply access those directly.

In addition, refactor the code so that the blocks of code which calculate
the page cache and reclaimable components each resemble one another to
clearly indicate we cap both against wmark_low in the same fashion.

Link: https://lkml.kernel.org/r/20230827110848.43510-1-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Xueshi Hu
b72b3c9c34 mm/hugetlb: fix nodes huge page allocation when there are surplus pages 
In set_nr_huge_pages(), local variable "count" is used to record
persistent_huge_pages(), but when it cames to nodes huge page allocation,
the semantics changes to nr_huge_pages.  When there exists surplus huge
pages and using the interface under
/sys/devices/system/node/node*/hugepages to change huge page pool size,
this difference can result in the allocation of an unexpected number of
huge pages.

Steps to reproduce the bug:

Starting with:

				  Node 0          Node 1    Total
	HugePages_Total             0.00            0.00     0.00
	HugePages_Free              0.00            0.00     0.00
	HugePages_Surp              0.00            0.00     0.00

create 100 huge pages in Node 0 and consume it, then set Node 0 's
nr_hugepages to 0.

yields:

				  Node 0          Node 1    Total
	HugePages_Total           200.00            0.00   200.00
	HugePages_Free              0.00            0.00     0.00
	HugePages_Surp            200.00            0.00   200.00

write 100 to Node 1's nr_hugepages

		echo 100 > /sys/devices/system/node/node1/\
	hugepages/hugepages-2048kB/nr_hugepages

gets:

				  Node 0          Node 1    Total
	HugePages_Total           200.00          400.00   600.00
	HugePages_Free              0.00          400.00   400.00
	HugePages_Surp            200.00            0.00   200.00

Kernel is expected to create only 100 huge pages and it gives 200.

Link: https://lkml.kernel.org/r/20230829033343.467779-1-xueshi.hu@smartx.com
Fixes: 9a30523066 ("hugetlb: add per node hstate attributes")
Signed-off-by: Xueshi Hu <xueshi.hu@smartx.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Mike Kravetz
d8f5f7e445 hugetlb: set hugetlb page flag before optimizing vmemmap 
Currently, vmemmap optimization of hugetlb pages is performed before the
hugetlb flag (previously hugetlb destructor) is set identifying it as a
hugetlb folio.  This means there is a window of time where an ordinary
folio does not have all associated vmemmap present.  The core mm only
expects vmemmap to be potentially optimized for hugetlb and device dax. 
This can cause problems in code such as memory error handling that may
want to write to tail struct pages.

There is only one call to perform hugetlb vmemmap optimization today.  To
fix this issue, simply set the hugetlb flag before that call.

There was a similar issue in the free hugetlb path that was previously
addressed.  The two routines that optimize or restore hugetlb vmemmap
should only be passed hugetlb folios/pages.  To catch any callers not
following this rule, add VM_WARN_ON calls to the routines.  In the hugetlb
free code paths, some calls could be made to restore vmemmap after
clearing the hugetlb flag.  This was 'safe' as in these cases vmemmap was
already present and the call was a NOOP.  However, for consistency these
calls where eliminated so that we can add the VM_WARN_ON checks.

Link: https://lkml.kernel.org/r/20230829213734.69673-1-mike.kravetz@oracle.com
Fixes: f41f2ed43c ("mm: hugetlb: free the vmemmap pages associated with each HugeTLB page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Usama Arif <usama.arif@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Anthony Yznaga
dd34d9fe3b mm: fix unaccount of memory on vma_link() failure 
Fix insert_vm_struct() so that only accounted memory is unaccounted if
vma_link() fails.

Link: https://lkml.kernel.org/r/20230830004324.16101-1-anthony.yznaga@oracle.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Anthony Yznaga
954652b9f3 mm/mremap: fix unaccount of memory on vma_merge() failure 
Fix mremap so that only accounted memory is unaccounted if the mapping is
expandable but vma_merge() fails.

Link: https://lkml.kernel.org/r/20230830004549.16131-1-anthony.yznaga@oracle.com
Fixes: fdbef61491 ("mm/mremap: don't account pages in vma_to_resize()")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
e19a3f595a mm/compaction: factor out code to test if we should run compaction for target order 
We always do zone_watermark_ok check and compaction_suitable check
together to test if compaction for target order should be ran.  Factor
these code out to remove repeat code.

Link: https://lkml.kernel.org/r/20230901155141.249860-7-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
9cc17ede51 mm/compaction: improve comment of is_via_compact_memory 
We do proactive compaction with order == -1 via
1. /proc/sys/vm/compact_memory
2. /sys/devices/system/node/nodex/compact
3. /proc/sys/vm/compaction_proactiveness
Add missed situation in which order == -1.

Link: https://lkml.kernel.org/r/20230901155141.249860-6-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
8df4e28c64 mm/compaction: remove repeat compact_blockskip_flush check in reset_isolation_suitable 
We have compact_blockskip_flush check in __reset_isolation_suitable, just
remove repeat check before __reset_isolation_suitable in
compact_blockskip_flush.

Link: https://lkml.kernel.org/r/20230901155141.249860-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
3da0272a4c mm/compaction: correctly return failure with bogus compound_order in strict mode 
In strict mode, we should return 0 if there is any hole in pageblock.  If
we successfully isolated pages at beginning at pageblock and then have a
bogus compound_order outside pageblock in next page.  We will abort search
loop with blockpfn > end_pfn.  Although we will limit blockpfn to end_pfn,
we will treat it as a successful isolation in strict mode as blockpfn is
not < end_pfn and return partial isolated pages.  Then
isolate_freepages_range may success unexpectly with hole in isolated
range.

Link: https://lkml.kernel.org/r/20230901155141.249860-4-shikemeng@huaweicloud.com
Fixes: 9fcd6d2e05 ("mm, compaction: skip compound pages by order in free scanner")
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
4c17989116 mm/compaction: call list_is_{first}/{last} more intuitively in move_freelist_{head}/{tail} 
We use move_freelist_head after list_for_each_entry_reverse to skip recent
pages.  And there is no need to do actual move if all freepages are
searched in list_for_each_entry_reverse, e.g.  freepage point to first
page in freelist.  It's more intuitively to call list_is_first with list
entry as the first argument and list head as the second argument to check
if list entry is the first list entry instead of call list_is_last with
list entry and list head passed in reverse.

Similarly, call list_is_last in move_freelist_tail is more intuitively.

Link: https://lkml.kernel.org/r/20230901155141.249860-3-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kemeng Shi
bbefa0fc04 mm/compaction: use correct list in move_freelist_{head}/{tail} 
Patch series "Fixes and cleanups to compaction", v3.

This is a series to do fix and clean up to compaction.
Patch 1-2 fix and clean up freepage list operation.
Patch 3-4 fix and clean up isolation of freepages
Patch 7 factor code to check if compaction is needed for allocation order.

More details can be found in respective patches. 


This patch (of 6):

The freepage is chained with buddy_list in freelist head. Use buddy_list
instead of lru to correct the list operation.

Link: https://lkml.kernel.org/r/20230901155141.249860-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20230901155141.249860-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:19 -07:00
Kees Cook
2632bb84d1 mm: Remove unused vm_brk() 
With fs/binfmt_elf.c fully refactored to use the new elf_load() helper,
there are no more users of vm_brk(), so remove it.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Tested-by: Pedro Falcato <pedro.falcato@gmail.com>
Signed-off-by: Sebastian Ott <sebott@redhat.com>
Link: https://lore.kernel.org/r/20230929032435.2391507-6-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
 2023-10-03 19:48:44 -07:00
Vlastimil Babka
90f055df11 mm/slub: refactor calculate_order() and calc_slab_order() 
After the previous cleanups, we can now move some code from
calc_slab_order() to calculate_order() so it's executed just once, and
do some more cleanups.

- move the min_order and MAX_OBJS_PER_PAGE evaluation to
  calculate_order().

- change calc_slab_order() parameter min_objects to min_order

Also make MAX_OBJS_PER_PAGE check more robust by considering also
min_objects in addition to slub_min_order. Otherwise this is not a
functional change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-and-tested-by: Jay Patel <jaypatel@linux.ibm.com>
 2023-10-02 11:55:47 +02:00
Vlastimil Babka
5886fc82b6 mm/slub: attempt to find layouts up to 1/2 waste in calculate_order() 
The main loop in calculate_order() currently tries to find an order with
at most 1/4 waste. If that's impossible (for particular large object
sizes), there's a fallback that will try to place one object within
slab_max_order.

If we expand the loop boundary to also allow up to 1/2 waste as the last
resort, we can remove the fallback and simplify the code, as the loop
will find an order for such sizes as well. Note we don't need to allow
more than 1/2 waste as that will never happen - calc_slab_order() would
calculate more objects to fit, reducing waste below 1/2.

Successfully finding an order in the loop (compared to the fallback)
will also have the benefit in trying to satisfy min_objects, because the
fallback was passing 1. Thus the resulting slab orders might be larger
(not because it would improve waste, but to reduce pressure on shared
locks), which is one of the goals of calculate_order().

For example, with nr_cpus=1 and 4kB PAGE_SIZE, slub_max_order=3, before
the patch we would get the following orders for these object sizes:

 2056 to 10920 - order-3 as selected by the loop
10928 to 12280 - order-2 due to fallback, as <1/4 waste is not possible
12288 to 32768 - order-3 as <1/4 waste is again possible

After the patch:

2056 to 32768 - order-3, because even in the range of 10928 to 12280 we
                try to satisfy the calculated min_objects.

As a result the code is simpler and gives more consistent results.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-and-tested-by: Jay Patel <jaypatel@linux.ibm.com>
 2023-10-02 11:55:41 +02:00
Vlastimil Babka
0fe2735d5e mm/slub: remove min_objects loop from calculate_order() 
calculate_order() currently has two nested loops. The inner one that
gradually modifies the acceptable waste from 1/16 up to 1/4, and the
outer one that decreases min_objects down to 2.

Upon closer inspection, the outer loop is unnecessary. Decreasing
min_objects could have in theory two effects to make the inner loop and
its call to calc_slab_order() succeed where a previous iteration with
higher min_objects would not:

- it could cause the min_objects-derived min_order to fit within
  slub_max_order. But min_objects is already pre-capped to max_objects
  that's derived from slub_max_order above the loops, so every iteration
  tries at least slub_max_order in calc_slab_order()

- it could cause calc_slab_order() to be called with lower min_objects
  thus potentially lower min_order in its loop. This would make a
  difference if the lower order could cause the fractional waste test to
  succeed where a higher order has already failed with same fract_leftover
  in the previous iteration with a higher min_order. But that's not
  possible, because increasing the order can only result in lower (or
  same) fractional waste. If we increase the slab size 2 times, we will
  fit at least 2 times the number of objects (thus same fraction of
  waste), or it will allow us to fit one more object (lower fraction of
  waste).

For more confidence I have tried adding a printk to notify when
decreasing min_objects resulted in a success, and simulated calculations
for a range of object sizes, nr_cpus and page_sizes. As expected, the
printk never triggered.

Thus remove the outer loop and adjust comments accordingly.

There's almost no functional change except a weird corner case when
slub_min_objects=1 on boot command line would cause the whole two nested
loops to be skipped before this patch. Now it would try to find the best
layout as usual, resulting in potentially higher orderthat minimizes
waste. This is not wrong and will be further expanded by the next patch.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-and-tested-by: Jay Patel <jaypatel@linux.ibm.com>
 2023-10-02 11:55:33 +02:00
Vlastimil Babka
c7355d7556 mm/slub: simplify the last resort slab order calculation 
If calculate_order() can't fit even a single large object within
slub_max_order, it will try using the smallest necessary order that may
exceed slub_max_order but not MAX_ORDER.

Currently this is done with a call to calc_slab_order() which is
unnecessary. We can simply use get_order(size). No functional change.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-and-tested-by: Jay Patel <jaypatel@linux.ibm.com>
 2023-10-02 11:54:32 +02:00
Feng Tang
e519ce7a26 mm/slub: add sanity check for slub_min/max_order cmdline setup 
Currently there are 2 parameters could be setup from kernel cmdline:
slub_min_order and slub_max_order. It's possible that the user
configured slub_min_order is bigger than the default slub_max_order
[1], which can still take effect, as calculate_oder() will use MAX_ORDER
as a fallback to check against, but has some downsides:

* the kernel message about SLUB will be strange in showing min/max
  orders:

    SLUB: HWalign=64, Order=9-3, MinObjects=0, CPUs=16, Nodes=1

* in calculate_order() called by each slab, the 2 loops of
  calc_slab_order() will all be meaningless due to slub_min_order
  is bigger than slub_max_order

* prevent future code cleanup like in [2].

Fix it by adding some sanity check to enforce the min/max semantics.

[1]. https://lore.kernel.org/lkml/21a0ba8b-bf05-0799-7c78-2a35f8c8d52a@os.amperecomputing.com/
[2]. https://lore.kernel.org/lkml/20230908145302.30320-7-vbabka@suse.cz/

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
 2023-10-02 11:54:32 +02:00
Linus Torvalds
d2c5231581 Fourteen hotfixes, eleven of which are cc:stable. The remainder pertain 
to issues which were introduced after 6.5.
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Merge tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Fourteen hotfixes, eleven of which are cc:stable. The remainder
  pertain to issues which were introduced after 6.5"

* tag 'mm-hotfixes-stable-2023-10-01-08-34' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  Crash: add lock to serialize crash hotplug handling
  selftests/mm: fix awk usage in charge_reserved_hugetlb.sh and hugetlb_reparenting_test.sh that may cause error
  mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified
  mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions()
  mm, memcg: reconsider kmem.limit_in_bytes deprecation
  mm: zswap: fix potential memory corruption on duplicate store
  arm64: hugetlb: fix set_huge_pte_at() to work with all swap entries
  mm: hugetlb: add huge page size param to set_huge_pte_at()
  maple_tree: add MAS_UNDERFLOW and MAS_OVERFLOW states
  maple_tree: add mas_is_active() to detect in-tree walks
  nilfs2: fix potential use after free in nilfs_gccache_submit_read_data()
  mm: abstract moving to the next PFN
  mm: report success more often from filemap_map_folio_range()
  fs: binfmt_elf_efpic: fix personality for ELF-FDPIC
 2023-10-01 13:33:25 -07:00
Yang Shi
24526268f4 mm: mempolicy: keep VMA walk if both MPOL_MF_STRICT and MPOL_MF_MOVE are specified 
When calling mbind() with MPOL_MF_{MOVE|MOVEALL} | MPOL_MF_STRICT, kernel
should attempt to migrate all existing pages, and return -EIO if there is
misplaced or unmovable page.  Then commit 6f4576e368 ("mempolicy: apply
page table walker on queue_pages_range()") messed up the return value and
didn't break VMA scan early ianymore when MPOL_MF_STRICT alone.  The
return value problem was fixed by commit a7f40cfe3b ("mm: mempolicy:
make mbind() return -EIO when MPOL_MF_STRICT is specified"), but it broke
the VMA walk early if unmovable page is met, it may cause some pages are
not migrated as expected.

The code should conceptually do:

 if (MPOL_MF_MOVE|MOVEALL)
     scan all vmas
     try to migrate the existing pages
     return success
 else if (MPOL_MF_MOVE* | MPOL_MF_STRICT)
     scan all vmas
     try to migrate the existing pages
     return -EIO if unmovable or migration failed
 else /* MPOL_MF_STRICT alone */
     break early if meets unmovable and don't call mbind_range() at all
 else /* none of those flags */
     check the ranges in test_walk, EFAULT without mbind_range() if discontig.

Fixed the behavior.

Link: https://lkml.kernel.org/r/20230920223242.3425775-1-yang@os.amperecomputing.com
Fixes: a7f40cfe3b ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified")
Signed-off-by: Yang Shi <yang@os.amperecomputing.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: David Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[4.9+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:48 -07:00
Jinjie Ruan
45120b1574 mm/damon/vaddr-test: fix memory leak in damon_do_test_apply_three_regions() 
When CONFIG_DAMON_VADDR_KUNIT_TEST=y and making CONFIG_DEBUG_KMEMLEAK=y
and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, the below memory leak is detected.

Since commit 9f86d62429 ("mm/damon/vaddr-test: remove unnecessary
variables"), the damon_destroy_ctx() is removed, but still call
damon_new_target() and damon_new_region(), the damon_region which is
allocated by kmem_cache_alloc() in damon_new_region() and the damon_target
which is allocated by kmalloc in damon_new_target() are not freed.  And
the damon_region which is allocated in damon_new_region() in
damon_set_regions() is also not freed.

So use damon_destroy_target to free all the damon_regions and damon_target.

    unreferenced object 0xffff888107c9a940 (size 64):
      comm "kunit_try_catch", pid 1069, jiffies 4294670592 (age 732.761s)
      hex dump (first 32 bytes):
        00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b  ............kkkk
        60 c7 9c 07 81 88 ff ff f8 cb 9c 07 81 88 ff ff  `...............
      backtrace:
        [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
        [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
        [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
        [<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff8881079cc740 (size 56):
      comm "kunit_try_catch", pid 1069, jiffies 4294670592 (age 732.761s)
      hex dump (first 32 bytes):
        05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
        6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
      backtrace:
        [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
        [<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
        [<ffffffff819c82be>] damon_test_apply_three_regions1+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff888107c9ac40 (size 64):
      comm "kunit_try_catch", pid 1071, jiffies 4294670595 (age 732.843s)
      hex dump (first 32 bytes):
        00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b  ............kkkk
        a0 cc 9c 07 81 88 ff ff 78 a1 76 07 81 88 ff ff  ........x.v.....
      backtrace:
        [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
        [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
        [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
        [<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff8881079ccc80 (size 56):
      comm "kunit_try_catch", pid 1071, jiffies 4294670595 (age 732.843s)
      hex dump (first 32 bytes):
        05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
        6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
      backtrace:
        [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
        [<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
        [<ffffffff819c851e>] damon_test_apply_three_regions2+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff888107c9af40 (size 64):
      comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.011s)
      hex dump (first 32 bytes):
        00 00 00 00 00 00 00 00 06 00 00 00 6b 6b 6b 6b  ............kkkk
        20 a2 76 07 81 88 ff ff b8 a6 76 07 81 88 ff ff   .v.......v.....
      backtrace:
        [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
        [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
        [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
        [<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff88810776a200 (size 56):
      comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.011s)
      hex dump (first 32 bytes):
        05 00 00 00 00 00 00 00 14 00 00 00 00 00 00 00  ................
        6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
      backtrace:
        [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
        [<ffffffff819c7d91>] damon_do_test_apply_three_regions.constprop.0+0xd1/0x3e0
        [<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff88810776a740 (size 56):
      comm "kunit_try_catch", pid 1073, jiffies 4294670597 (age 733.025s)
      hex dump (first 32 bytes):
        3d 00 00 00 00 00 00 00 3f 00 00 00 00 00 00 00  =.......?.......
        6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
      backtrace:
        [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
        [<ffffffff819bfcc2>] damon_set_regions+0x4c2/0x8e0
        [<ffffffff819c7dbb>] damon_do_test_apply_three_regions.constprop.0+0xfb/0x3e0
        [<ffffffff819c877e>] damon_test_apply_three_regions3+0x21e/0x260
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff888108038240 (size 64):
      comm "kunit_try_catch", pid 1075, jiffies 4294670600 (age 733.022s)
      hex dump (first 32 bytes):
        00 00 00 00 00 00 00 00 03 00 00 00 6b 6b 6b 6b  ............kkkk
        48 ad 76 07 81 88 ff ff 98 ae 76 07 81 88 ff ff  H.v.......v.....
      backtrace:
        [<ffffffff817e0167>] kmalloc_trace+0x27/0xa0
        [<ffffffff819c11cf>] damon_new_target+0x3f/0x1b0
        [<ffffffff819c7d55>] damon_do_test_apply_three_regions.constprop.0+0x95/0x3e0
        [<ffffffff819c898d>] damon_test_apply_three_regions4+0x1cd/0x210
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20
    unreferenced object 0xffff88810776ad28 (size 56):
      comm "kunit_try_catch", pid 1075, jiffies 4294670600 (age 733.022s)
      hex dump (first 32 bytes):
        05 00 00 00 00 00 00 00 07 00 00 00 00 00 00 00  ................
        6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 6b 6b 6b 6b  kkkkkkkk....kkkk
      backtrace:
        [<ffffffff819bc492>] damon_new_region+0x22/0x1c0
        [<ffffffff819bfcc2>] damon_set_regions+0x4c2/0x8e0
        [<ffffffff819c7dbb>] damon_do_test_apply_three_regions.constprop.0+0xfb/0x3e0
        [<ffffffff819c898d>] damon_test_apply_three_regions4+0x1cd/0x210
        [<ffffffff829fce6a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
        [<ffffffff81237cf6>] kthread+0x2b6/0x380
        [<ffffffff81097add>] ret_from_fork+0x2d/0x70
        [<ffffffff81003791>] ret_from_fork_asm+0x11/0x20

Link: https://lkml.kernel.org/r/20230925072100.3725620-1-ruanjinjie@huawei.com
Fixes: 9f86d62429 ("mm/damon/vaddr-test: remove unnecessary variables")
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:47 -07:00
Michal Hocko
4597648fdd mm, memcg: reconsider kmem.limit_in_bytes deprecation 
This reverts commits 86327e8eb9 ("memcg: drop kmem.limit_in_bytes") and
partially reverts 58056f7750 ("memcg, kmem: further deprecate
kmem.limit_in_bytes") which have incrementally removed support for the
kernel memory accounting hard limit.  Unfortunately it has turned out that
there is still userspace depending on the existence of
memory.kmem.limit_in_bytes [1].  The underlying functionality is not
really required but the non-existent file just confuses the userspace
which fails in the result.  The patch to fix this on the userspace side
has been submitted but it is hard to predict how it will propagate through
the maze of 3rd party consumers of the software.

Now, reverting alone 86327e8eb9 is not an option because there is
another set of userspace which cannot cope with ENOTSUPP returned when
writing to the file.  Therefore we have to go and revisit 58056f7750 as
well.  There are two ways to go ahead.  Either we give up on the
deprecation and fully revert 58056f7750 as well or we can keep
kmem.limit_in_bytes but make the write a noop and warn about the fact. 
This should work for both known breaking workloads which depend on the
existence but do not depend on the hard limit enforcement.

Note to backporters to stable trees.  a8c49af3be ("memcg: add per-memcg
total kernel memory stat") introduced in 4.18 has added memcg_account_kmem
so the accounting is not done by obj_cgroup_charge_pages directly for v1
anymore.  Prior kernels need to add it explicitly (thanks to Johannes for
pointing this out).

[akpm@linux-foundation.org: fix build - remove unused local]
Link: http://lkml.kernel.org/r/20230920081101.GA12096@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net [1]
Link: https://lkml.kernel.org/r/ZRE5VJozPZt9bRPy@dhcp22.suse.cz
Fixes: 86327e8eb9 ("memcg: drop kmem.limit_in_bytes")
Fixes: 58056f7750 ("memcg, kmem: further deprecate kmem.limit_in_bytes")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:47 -07:00
Domenico Cerasuolo
ca56489c2f mm: zswap: fix potential memory corruption on duplicate store 
While stress-testing zswap a memory corruption was happening when writing
back pages.  __frontswap_store used to check for duplicate entries before
attempting to store a page in zswap, this was because if the store fails
the old entry isn't removed from the tree.  This change removes duplicate
entries in zswap_store before the actual attempt.

[cerasuolodomenico@gmail.com: add a warning and a comment, per Johannes]
  Link: https://lkml.kernel.org/r/20230925130002.1929369-1-cerasuolodomenico@gmail.com
Link: https://lkml.kernel.org/r/20230922172211.1704917-1-cerasuolodomenico@gmail.com
Fixes: 42c06a0e8e ("mm: kill frontswap")
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:47 -07:00
Ryan Roberts
935d4f0c6d mm: hugetlb: add huge page size param to set_huge_pte_at() 
Patch series "Fix set_huge_pte_at() panic on arm64", v2.

This series fixes a bug in arm64's implementation of set_huge_pte_at(),
which can result in an unprivileged user causing a kernel panic.  The
problem was triggered when running the new uffd poison mm selftest for
HUGETLB memory.  This test (and the uffd poison feature) was merged for
v6.5-rc7.

Ideally, I'd like to get this fix in for v6.6 and I've cc'ed stable
(correctly this time) to get it backported to v6.5, where the issue first
showed up.


Description of Bug
==================

arm64's huge pte implementation supports multiple huge page sizes, some of
which are implemented in the page table with multiple contiguous entries. 
So set_huge_pte_at() needs to work out how big the logical pte is, so that
it can also work out how many physical ptes (or pmds) need to be written. 
It previously did this by grabbing the folio out of the pte and querying
its size.

However, there are cases when the pte being set is actually a swap entry. 
But this also used to work fine, because for huge ptes, we only ever saw
migration entries and hwpoison entries.  And both of these types of swap
entries have a PFN embedded, so the code would grab that and everything
still worked out.

But over time, more calls to set_huge_pte_at() have been added that set
swap entry types that do not embed a PFN.  And this causes the code to go
bang.  The triggering case is for the uffd poison test, commit
99aa77215a ("selftests/mm: add uffd unit test for UFFDIO_POISON"), which
causes a PTE_MARKER_POISONED swap entry to be set, coutesey of commit
8a13897fb0 ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs") -
added in v6.5-rc7.  Although review shows that there are other call sites
that set PTE_MARKER_UFFD_WP (which also has no PFN), these don't trigger
on arm64 because arm64 doesn't support UFFD WP.

If CONFIG_DEBUG_VM is enabled, we do at least get a BUG(), but otherwise,
it will dereference a bad pointer in page_folio():

    static inline struct folio *hugetlb_swap_entry_to_folio(swp_entry_t entry)
    {
        VM_BUG_ON(!is_migration_entry(entry) && !is_hwpoison_entry(entry));

        return page_folio(pfn_to_page(swp_offset_pfn(entry)));
    }


Fix
===

The simplest fix would have been to revert the dodgy cleanup commit
18f3962953 ("mm: hugetlb: kill set_huge_swap_pte_at()"), but since
things have moved on, this would have required an audit of all the new
set_huge_pte_at() call sites to see if they should be converted to
set_huge_swap_pte_at().  As per the original intent of the change, it
would also leave us open to future bugs when people invariably get it
wrong and call the wrong helper.

So instead, I've added a huge page size parameter to set_huge_pte_at(). 
This means that the arm64 code has the size in all cases.  It's a bigger
change, due to needing to touch the arches that implement the function,
but it is entirely mechanical, so in my view, low risk.

I've compile-tested all touched arches; arm64, parisc, powerpc, riscv,
s390, sparc (and additionally x86_64).  I've additionally booted and run
mm selftests against arm64, where I observe the uffd poison test is fixed,
and there are no other regressions.


This patch (of 2):

In order to fix a bug, arm64 needs to be told the size of the huge page
for which the pte is being set in set_huge_pte_at().  Provide for this by
adding an `unsigned long sz` parameter to the function.  This follows the
same pattern as huge_pte_clear().

This commit makes the required interface modifications to the core mm as
well as all arches that implement this function (arm64, parisc, powerpc,
riscv, s390, sparc).  The actual arm64 bug will be fixed in a separate
commit.

No behavioral changes intended.

Link: https://lkml.kernel.org/r/20230922115804.2043771-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20230922115804.2043771-2-ryan.roberts@arm.com
Fixes: 8a13897fb0 ("mm: userfaultfd: support UFFDIO_POISON for hugetlbfs")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>	[powerpc 8xx]
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>	[vmalloc change]
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: <stable@vger.kernel.org>	[6.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:47 -07:00
Matthew Wilcox (Oracle)
a501a07030 mm: report success more often from filemap_map_folio_range() 
Even though we had successfully mapped the relevant page, we would rarely
return success from filemap_map_folio_range().  That leads to falling back
from the VMA lock path to the mmap_lock path, which is a speed &
scalability issue.  Found by inspection.

Link: https://lkml.kernel.org/r/20230920035336.854212-1-willy@infradead.org
Fixes: 617c28ecab ("filemap: batch PTE mappings")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-29 17:20:45 -07:00
Linus Torvalds
1c84724ccb slab fixes for 6.6-rc4 
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Merge tag 'slab-fixes-for-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab fixes from Vlastimil Babka:

 - stable fix to prevent list corruption when destroying caches with
   leftover objects (Rafael Aquini)

 - fix for a gotcha in kmalloc_size_roundup() when calling it with too
   high size, discovered when recently a networking call site had to be
   fixed for a different issue (David Laight)

* tag 'slab-fixes-for-6.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  slab: kmalloc_size_roundup() must not return 0 for non-zero size
  mm/slab_common: fix slab_caches list corruption after kmem_cache_destroy()
 2023-09-29 12:10:12 -07:00
Song Shuai
e96c6b8f21 memblock: report failures when memblock_can_resize is not set 
The callers of memblock_reserve() do not check the return value
presuming that memblock_reserve() always succeeds, but there are
cases where it may fail.

Having numerous memblock reservations at early boot where
memblock_can_resize is unset may exhaust the INIT_MEMBLOCK_REGIONS sized
memblock.reserved regions array and an attempt to double this array via
memblock_double_array() will fail and will return -1 to the caller.

When this happens the system crashes anyway, but it's hard to identify
the reason for the crash.

Add a panic message to memblock_double_array() to aid debugging of the
cases when too many regions are reserved before memblock can resize
memblock.reserved array.

Link: https://lore.kernel.org/linux-kernel/20230614131746.3670303-1-songshuaishuai@tinylab.org/
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Link: https://lore.kernel.org/r/20230624032607.921173-1-songshuaishuai@tinylab.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2023-09-28 09:04:33 +03:00
Linus Torvalds
85eba5f175 13 hotfixes, 10 of which pertain to post-6.5 issues. The other 3 are 
cc:stable.
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Merge tag 'mm-hotfixes-stable-2023-09-23-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "13 hotfixes, 10 of which pertain to post-6.5 issues. The other three
  are cc:stable"

* tag 'mm-hotfixes-stable-2023-09-23-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  proc: nommu: fix empty /proc/<pid>/maps
  filemap: add filemap_map_order0_folio() to handle order0 folio
  proc: nommu: /proc/<pid>/maps: release mmap read lock
  mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement
  pidfd: prevent a kernel-doc warning
  argv_split: fix kernel-doc warnings
  scatterlist: add missing function params to kernel-doc
  selftests/proc: fixup proc-empty-vm test after KSM changes
  revert "scripts/gdb/symbols: add specific ko module load command"
  selftests: link libasan statically for tests with -fsanitize=address
  task_work: add kerneldoc annotation for 'data' argument
  mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list
  sh: mm: re-add lost __ref to ioremap_prot() to fix modpost warning
 2023-09-23 11:51:16 -07:00
Linus Torvalds
93397d3a2f LoongArch fixes for v6.6-rc3 
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Merge tag 'loongarch-fixes-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch fixes from Huacai Chen:
 "Fix lockdep, fix a boot failure, fix some build warnings, fix document
  links, and some cleanups"

* tag 'loongarch-fixes-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  docs/zh_CN/LoongArch: Update the links of ABI
  docs/LoongArch: Update the links of ABI
  LoongArch: Don't inline kasan_mem_to_shadow()/kasan_shadow_to_mem()
  kasan: Cleanup the __HAVE_ARCH_SHADOW_MAP usage
  LoongArch: Set all reserved memblocks on Node#0 at initialization
  LoongArch: Remove dead code in relocate_new_kernel
  LoongArch: Use _UL() and _ULL()
  LoongArch: Fix some build warnings with W=1
  LoongArch: Fix lockdep static memory detection
 2023-09-23 10:57:03 -07:00
Paolo Abeni
e9cbc89067 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 
Cross-merge networking fixes after downstream PR.

No conflicts.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
 2023-09-21 21:49:45 +02:00
Christian Brauner
db58b5eea8
Revert "tmpfs: add support for multigrain timestamps" 
This reverts commit d48c339729.

Users reported regressions due to enabling multi-grained timestamps
unconditionally. As no clear consensus on a solution has come up and the
discussion has gone back to the drawing board revert the infrastructure
changes for. If it isn't code that's here to stay, make it go away.

Message-ID: <20230920-keine-eile-c9755b5825db@brauner>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2023-09-20 18:05:30 +02:00
David Laight
8446a4deb6 slab: kmalloc_size_roundup() must not return 0 for non-zero size 
The typical use of kmalloc_size_roundup() is:

	ptr = kmalloc(sz = kmalloc_size_roundup(size), ...);
	if (!ptr) return -ENOMEM.

This means it is vitally important that the returned value isn't less
than the argument even if the argument is insane.
In particular if kmalloc_slab() fails or the value is above
(MAX_ULONG - PAGE_SIZE) zero is returned and kmalloc() will return
its single zero-length buffer ZERO_SIZE_PTR.

Fix this by returning the input size if the size exceeds
KMALLOC_MAX_SIZE. kmalloc() will then return NULL as the size really is
too big.

kmalloc_slab() should not normally return NULL, unless called too early.
Again, returning zero is not the correct action as it can be in some
usage scenarios stored to a variable and only later cause kmalloc()
return ZERO_SIZE_PTR and subsequent crashes on access. Instead we can
simply stop checking the kmalloc_slab() result completely, as calling
kmalloc_size_roundup() too early would then result in an immediate crash
during boot and the developer noticing an issue in their code.

[vbabka@suse.cz: remove kmalloc_slab() result check, tweak comments and
 commit log]
Fixes: 05a940656e ("slab: Introduce kmalloc_size_roundup()")
Signed-off-by: David Laight <david.laight@aculab.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
 2023-09-20 14:50:22 +02:00
Huacai Chen
2a86f1b56a kasan: Cleanup the __HAVE_ARCH_SHADOW_MAP usage 
As Linus suggested, __HAVE_ARCH_XYZ is "stupid" and "having historical
uses of it doesn't make it good". So migrate __HAVE_ARCH_SHADOW_MAP to
separate macros named after the respective functions.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
 2023-09-20 14:26:29 +08:00
Yin Fengwei
c8be038067 filemap: add filemap_map_order0_folio() to handle order0 folio 
Kernel test robot reported regressions for several benchmarks [1].
The regression are related with commit:
de74976eb6 ("filemap: add filemap_map_folio_range()")

It turned out that function filemap_map_folio_range() brings these
regressions when handle folio with order0.

Add filemap_map_order0_folio() to handle order0 folio. The benefit
come from two perspectives:
  - the code size is smaller (around 126 bytes)
  - no loop

Testing showed the regressions reported by 0day [1] all are fixed:
commit 9f1f5b60e7: parent commit of de74976eb6
commit fbdf9263a3d7fdbd: latest mm-unstable commit
commit 7fbfe2003f84686d: this fixing patch

9f1f5b60e7 fbdf9263a3d7fdbd            7fbfe2003f84686d
---------------- --------------------------- ---------------------------
   3843810           -21.4%    3020268            +4.6%    4018708      stress-ng.bad-altstack.ops
     64061           -21.4%      50336            +4.6%      66977      stress-ng.bad-altstack.ops_per_sec

   1709026           -14.4%    1462102            +2.4%    1750757      stress-ng.fork.ops
     28483           -14.4%      24368            +2.4%      29179      stress-ng.fork.ops_per_sec

   3685088           -53.6%    1710976            +0.5%    3702454      stress-ng.zombie.ops
     56732           -65.3%      19667            +0.7%      57107      stress-ng.zombie.ops_per_sec

     61874           -12.1%      54416            +0.4%      62136      vm-scalability.median
  13527663           -11.7%   11942117            -0.1%   13513946      vm-scalability.throughput
 4.066e+09           -11.7%   3.59e+09            -0.1%  4.061e+09      vm-scalability.workload

[1]:
https://lore.kernel.org/oe-lkp/72e017b9-deb6-44fa-91d6-716ee2c39cbc@intel.com/T/#m7d2bba30f75a9cee8eab07e5809abd9b3b206c84

Link: https://lkml.kernel.org/r/20230914134741.1937654-1-fengwei.yin@intel.com
Fixes: de74976eb6 ("filemap: add filemap_map_folio_range()")
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202309111556.b2aa3d7a-oliver.sang@intel.com
Cc: Feng Tang <feng.tang@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-19 13:21:34 -07:00
Johannes Weiner
9ea9cb00a8 mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement 
Breno and Josef report a deadlock scenario from cgroup reclaim
re-entering the filesystem:

[  361.546690] ======================================================
[  361.559210] WARNING: possible circular locking dependency detected
[  361.571703] 6.5.0-0_fbk700_debug_rc0_kbuilder_13159_gbf787a128001 #1 Tainted: G S          E
[  361.589704] ------------------------------------------------------
[  361.602277] find/9315 is trying to acquire lock:
[  361.611625] ffff88837ba140c0 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0x68/0x4f0
[  361.631437]
[  361.631437] but task is already holding lock:
[  361.643243] ffff8881765b8678 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock+0x1e/0x40

[  362.904457]  mutex_lock_nested+0x1c/0x30
[  362.912414]  __btrfs_release_delayed_node+0x68/0x4f0
[  362.922460]  btrfs_evict_inode+0x301/0x770
[  362.982726]  evict+0x17c/0x380
[  362.988944]  prune_icache_sb+0x100/0x1d0
[  363.005559]  super_cache_scan+0x1f8/0x260
[  363.013695]  do_shrink_slab+0x2a2/0x540
[  363.021489]  shrink_slab_memcg+0x237/0x3d0
[  363.050606]  shrink_slab+0xa7/0x240
[  363.083382]  shrink_node_memcgs+0x262/0x3b0
[  363.091870]  shrink_node+0x1a4/0x720
[  363.099150]  shrink_zones+0x1f6/0x5d0
[  363.148798]  do_try_to_free_pages+0x19b/0x5e0
[  363.157633]  try_to_free_mem_cgroup_pages+0x266/0x370
[  363.190575]  reclaim_high+0x16f/0x1f0
[  363.208409]  mem_cgroup_handle_over_high+0x10b/0x270
[  363.246678]  try_charge_memcg+0xaf2/0xc70
[  363.304151]  charge_memcg+0xf0/0x350
[  363.320070]  __mem_cgroup_charge+0x28/0x40
[  363.328371]  __filemap_add_folio+0x870/0xd50
[  363.371303]  filemap_add_folio+0xdd/0x310
[  363.399696]  __filemap_get_folio+0x2fc/0x7d0
[  363.419086]  pagecache_get_page+0xe/0x30
[  363.427048]  alloc_extent_buffer+0x1cd/0x6a0
[  363.435704]  read_tree_block+0x43/0xc0
[  363.443316]  read_block_for_search+0x361/0x510
[  363.466690]  btrfs_search_slot+0xc8c/0x1520

This is caused by the mem_cgroup_handle_over_high() not respecting the
gfp_mask of the allocation context.  We used to only call this function on
resume to userspace, where no locks were held.  But c9afe31ec4 ("memcg:
synchronously enforce memory.high for large overcharges") added a call
from the allocation context without considering the gfp.

Link: https://lkml.kernel.org/r/20230914152139.100822-1-hannes@cmpxchg.org
Fixes: c9afe31ec4 ("memcg: synchronously enforce memory.high for large overcharges")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Breno Leitao <leitao@debian.org>
Reported-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>	[5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-19 13:21:34 -07:00
Johannes Weiner
7b086755fb mm: page_alloc: fix CMA and HIGHATOMIC landing on the wrong buddy list 
Commit 4b23a68f95 ("mm/page_alloc: protect PCP lists with a spinlock")
bypasses the pcplist on lock contention and returns the page directly to
the buddy list of the page's migratetype.

For pages that don't have their own pcplist, such as CMA and HIGHATOMIC,
the migratetype is temporarily updated such that the page can hitch a ride
on the MOVABLE pcplist.  Their true type is later reassessed when flushing
in free_pcppages_bulk().  However, when lock contention is detected after
the type was already overridden, the bypass will then put the page on the
wrong buddy list.

Once on the MOVABLE buddy list, the page becomes eligible for fallbacks
and even stealing.  In the case of HIGHATOMIC, otherwise ineligible
allocations can dip into the highatomic reserves.  In the case of CMA, the
page can be lost from the CMA region permanently.

Use a separate pcpmigratetype variable for the pcplist override.  Use the
original migratetype when going directly to the buddy.  This fixes the bug
and should make the intentions more obvious in the code.

Originally sent here to address the HIGHATOMIC case:
https://lore.kernel.org/lkml/20230821183733.106619-4-hannes@cmpxchg.org/

Changelog updated in response to the CMA-specific bug report.

[mgorman@techsingularity.net: updated changelog]
Link: https://lkml.kernel.org/r/20230911181108.GA104295@cmpxchg.org
Fixes: 4b23a68f95 ("mm/page_alloc: protect PCP lists with a spinlock")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Joe Liu <joe.liu@mediatek.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-19 13:21:32 -07:00
David S. Miller
685c6d5b2c Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next 
Alexei Starovoitov says:

====================
The following pull-request contains BPF updates for your *net-next* tree.

We've added 73 non-merge commits during the last 9 day(s) which contain
a total of 79 files changed, 5275 insertions(+), 600 deletions(-).

The main changes are:

1) Basic BTF validation in libbpf, from Andrii Nakryiko.

2) bpf_assert(), bpf_throw(), exceptions in bpf progs, from Kumar Kartikeya Dwivedi.

3) next_thread cleanups, from Oleg Nesterov.

4) Add mcpu=v4 support to arm32, from Puranjay Mohan.

5) Add support for __percpu pointers in bpf progs, from Yonghong Song.

6) Fix bpf tailcall interaction with bpf trampoline, from Leon Hwang.

7) Raise irq_work in bpf_mem_alloc while irqs are disabled to improve refill probabablity, from Hou Tao.

Please consider pulling these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git

Thanks a lot!

Also thanks to reporters, reviewers and testers of commits in this pull-request:

Alan Maguire, Andrey Konovalov, Dave Marchevsky, "Eric W. Biederman",
Jiri Olsa, Maciej Fijalkowski, Quentin Monnet, Russell King (Oracle),
Song Liu, Stanislav Fomichev, Yonghong Song
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
 2023-09-17 15:12:06 +01:00
Linus Torvalds
3cec504909 vm: fix move_vma() memory accounting being off 
Commit 408579cd62 ("mm: Update do_vmi_align_munmap() return
semantics") seems to have updated one of the callers of do_vmi_munmap()
incorrectly: it used to check for the error case (which didn't
change: negative means error).

That commit changed the check to the success case (which did change:
before that commit, 0 was success, and 1 was "success and lock
downgraded".  After the change, it's always 0 for success, and the lock
will have been released if requested).

This didn't change any actual VM behavior _except_ for memory accounting
when 'VM_ACCOUNT' was set on the vma.  Which made the wrong return value
test fairly subtle, since everything continues to work.

Or rather - it continues to work but the "Committed memory" accounting
goes all wonky (Committed_AS value in /proc/meminfo), and depending on
settings that then causes problems much much later as the VM relies on
bogus statistics for its heuristics.

Revert that one line of the change back to the original logic.

Fixes: 408579cd62 ("mm: Update do_vmi_align_munmap() return semantics")
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Reported-bisected-and-tested-by: Michael Labiuk <michael.labiuk@virtuozzo.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Link: https://lore.kernel.org/all/1694366957@msgid.manchmal.in-ulm.de/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2023-09-16 15:23:31 -07:00
Kumar Kartikeya Dwivedi
7ccb84f04c mm: kasan: Declare kasan_unpoison_task_stack_below in kasan.h 
We require access to this kasan helper in BPF code in the next patch
where we have to unpoison the task stack when we unwind and reset the
stack frame from bpf_throw, and it never really unpoisons the poisoned
stack slots on entry when compiler instrumentation is generated by
CONFIG_KASAN_STACK and inline instrumentation is supported.

Also, remove the declaration from mm/kasan/kasan.h as we put it in the
header file kasan.h.

Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Suggested-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20230912233214.1518551-10-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
 2023-09-16 09:34:21 -07:00
Yury Norov
b1f099b1cf numa: Generalize numa_map_to_online_node() 
The function in fact searches the nearest node for a given one,
based on a N_ONLINE state. This is a common pattern to search
for a nearest node.

This patch converts numa_map_to_online_node() to numa_nearest_node()
so that others won't need to opencode the logic.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Link: https://lore.kernel.org/r/20230819141239.287290-2-yury.norov@gmail.com
 2023-09-15 13:48:09 +02:00
Zhen Lei
6e284c55fc mm: Remove kmem_valid_obj() 
Function kmem_dump_obj() will splat if passed a pointer to a non-slab
object. So nothing calls it directly, instead calling kmem_valid_obj()
first to determine whether the passed pointer to a valid slab object. This
means that merging kmem_valid_obj() into kmem_dump_obj() will make the
code more concise. Therefore, convert kmem_dump_obj() to work the same
way as vmalloc_dump_obj(), removing the need for the kmem_dump_obj()
caller to check kmem_valid_obj().  After this, there are no remaining
calls to kmem_valid_obj() anymore, and it can be safely removed.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
 2023-09-13 22:28:59 +02:00
Rafael Aquini
46a9ea6681 mm/slab_common: fix slab_caches list corruption after kmem_cache_destroy() 
After the commit in Fixes:, if a module that created a slab cache does not
release all of its allocated objects before destroying the cache (at rmmod
time), we might end up releasing the kmem_cache object without removing it
from the slab_caches list thus corrupting the list as kmem_cache_destroy()
ignores the return value from shutdown_cache(), which in turn never removes
the kmem_cache object from slabs_list in case __kmem_cache_shutdown() fails
to release all of the cache's slabs.

This is easily observable on a kernel built with CONFIG_DEBUG_LIST=y
as after that ill release the system will immediately trip on list_add,
or list_del, assertions similar to the one shown below as soon as another
kmem_cache gets created, or destroyed:

  [ 1041.213632] list_del corruption. next->prev should be ffff89f596fb5768, but was 52f1e5016aeee75d. (next=ffff89f595a1b268)
  [ 1041.219165] ------------[ cut here ]------------
  [ 1041.221517] kernel BUG at lib/list_debug.c:62!
  [ 1041.223452] invalid opcode: 0000 [#1] PREEMPT SMP PTI
  [ 1041.225408] CPU: 2 PID: 1852 Comm: rmmod Kdump: loaded Tainted: G    B   W  OE      6.5.0 #15
  [ 1041.228244] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc37 05/24/2023
  [ 1041.231212] RIP: 0010:__list_del_entry_valid+0xae/0xb0

Another quick way to trigger this issue, in a kernel with CONFIG_SLUB=y,
is to set slub_debug to poison the released objects and then just run
cat /proc/slabinfo after removing the module that leaks slab objects,
in which case the kernel will panic:

  [   50.954843] general protection fault, probably for non-canonical address 0xa56b6b6b6b6b6b8b: 0000 [#1] PREEMPT SMP PTI
  [   50.961545] CPU: 2 PID: 1495 Comm: cat Kdump: loaded Tainted: G    B   W  OE      6.5.0 #15
  [   50.966808] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20230524-3.fc37 05/24/2023
  [   50.972663] RIP: 0010:get_slabinfo+0x42/0xf0

This patch fixes this issue by properly checking shutdown_cache()'s
return value before taking the kmem_cache_release() branch.

Fixes: 0495e337b7 ("mm/slab_common: Deleting kobject in kmem_cache_destroy() without holding slab_mutex/cpu_hotplug_lock")
Signed-off-by: Rafael Aquini <aquini@redhat.com>
Cc: stable@vger.kernel.org
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
 2023-09-11 13:02:01 +02:00
Ard Biesheuvel
cf8e865810 arch: Remove Itanium (IA-64) architecture 
The Itanium architecture is obsolete, and an informal survey [0] reveals
that any residual use of Itanium hardware in production is mostly HP-UX
or OpenVMS based. The use of Linux on Itanium appears to be limited to
enthusiasts that occasionally boot a fresh Linux kernel to see whether
things are still working as intended, and perhaps to churn out some
distro packages that are rarely used in practice.

None of the original companies behind Itanium still produce or support
any hardware or software for the architecture, and it is listed as
'Orphaned' in the MAINTAINERS file, as apparently, none of the engineers
that contributed on behalf of those companies (nor anyone else, for that
matter) have been willing to support or maintain the architecture
upstream or even be responsible for applying the odd fix. The Intel
firmware team removed all IA-64 support from the Tianocore/EDK2
reference implementation of EFI in 2018. (Itanium is the original
architecture for which EFI was developed, and the way Linux supports it
deviates significantly from other architectures.) Some distros, such as
Debian and Gentoo, still maintain [unofficial] ia64 ports, but many have
dropped support years ago.

While the argument is being made [1] that there is a 'for the common
good' angle to being able to build and run existing projects such as the
Grid Community Toolkit [2] on Itanium for interoperability testing, the
fact remains that none of those projects are known to be deployed on
Linux/ia64, and very few people actually have access to such a system in
the first place. Even if there were ways imaginable in which Linux/ia64
could be put to good use today, what matters is whether anyone is
actually doing that, and this does not appear to be the case.

There are no emulators widely available, and so boot testing Itanium is
generally infeasible for ordinary contributors. GCC still supports IA-64
but its compile farm [3] no longer has any IA-64 machines. GLIBC would
like to get rid of IA-64 [4] too because it would permit some overdue
code cleanups. In summary, the benefits to the ecosystem of having IA-64
be part of it are mostly theoretical, whereas the maintenance overhead
of keeping it supported is real.

So let's rip off the band aid, and remove the IA-64 arch code entirely.
This follows the timeline proposed by the Debian/ia64 maintainer [5],
which removes support in a controlled manner, leaving IA-64 in a known
good state in the most recent LTS release. Other projects will follow
once the kernel support is removed.

[0] https://lore.kernel.org/all/CAMj1kXFCMh_578jniKpUtx_j8ByHnt=s7S+yQ+vGbKt9ud7+kQ@mail.gmail.com/
[1] https://lore.kernel.org/all/0075883c-7c51-00f5-2c2d-5119c1820410@web.de/
[2] https://gridcf.org/gct-docs/latest/index.html
[3] https://cfarm.tetaneutral.net/machines/list/
[4] https://lore.kernel.org/all/87bkiilpc4.fsf@mid.deneb.enyo.de/
[5] https://lore.kernel.org/all/ff58a3e76e5102c94bb5946d99187b358def688a.camel@physik.fu-berlin.de/

Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
 2023-09-11 08:13:17 +00:00
Linus Torvalds
12952b6bbd LoongArch changes for v6.6 
1, Allow usage of LSX/LASX in the kernel;
 2, Add SIMD-optimized RAID5/RAID6 routines;
 3, Add Loongson Binary Translation (LBT) extension support;
 4, Add basic KGDB & KDB support;
 5, Add building with kcov coverage;
 6, Add KFENCE (Kernel Electric-Fence) support;
 7, Add KASAN (Kernel Address Sanitizer) support;
 8, Some bug fixes and other small changes;
 9, Update the default config file.
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Merge tag 'loongarch-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch updates from Huacai Chen:

 - Allow usage of LSX/LASX in the kernel, and use them for
   SIMD-optimized RAID5/RAID6 routines

 - Add Loongson Binary Translation (LBT) extension support

 - Add basic KGDB & KDB support

 - Add building with kcov coverage

 - Add KFENCE (Kernel Electric-Fence) support

 - Add KASAN (Kernel Address Sanitizer) support

 - Some bug fixes and other small changes

 - Update the default config file

* tag 'loongarch-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (25 commits)
  LoongArch: Update Loongson-3 default config file
  LoongArch: Add KASAN (Kernel Address Sanitizer) support
  LoongArch: Simplify the processing of jumping new kernel for KASLR
  kasan: Add (pmd|pud)_init for LoongArch zero_(pud|p4d)_populate process
  kasan: Add __HAVE_ARCH_SHADOW_MAP to support arch specific mapping
  LoongArch: Add KFENCE (Kernel Electric-Fence) support
  LoongArch: Get partial stack information when providing regs parameter
  LoongArch: mm: Add page table mapped mode support for virt_to_page()
  kfence: Defer the assignment of the local variable addr
  LoongArch: Allow building with kcov coverage
  LoongArch: Provide kaslr_offset() to get kernel offset
  LoongArch: Add basic KGDB & KDB support
  LoongArch: Add Loongson Binary Translation (LBT) extension support
  raid6: Add LoongArch SIMD recovery implementation
  raid6: Add LoongArch SIMD syndrome calculation
  LoongArch: Add SIMD-optimized XOR routines
  LoongArch: Allow usage of LSX/LASX in the kernel
  LoongArch: Define symbol 'fault' as a local label in fpu.S
  LoongArch: Adjust {copy, clear}_user exception handler behavior
  LoongArch: Use static defined zero page rather than allocated
  ...
 2023-09-08 12:16:52 -07:00
Qing Zhang
fb6d5c1d99 kasan: Add (pmd|pud)_init for LoongArch zero_(pud|p4d)_populate process 
LoongArch populates pmd/pud with invalid_pmd_table/invalid_pud_table in
pagetable_init, So pmd_init/pud_init(p) is required, define them as __weak
in mm/kasan/init.c, like mm/sparse-vmemmap.c.

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
 2023-09-06 22:54:16 +08:00
Qing Zhang
9b04c764af kasan: Add __HAVE_ARCH_SHADOW_MAP to support arch specific mapping 
MIPS, LoongArch and some other architectures have many holes between
different segments and the valid address space (256T available) is
insufficient to map all these segments to kasan shadow memory with the
common formula provided by kasan core. So we need architecture specific
mapping formulas to ensure different segments are mapped individually,
and only limited space lengths of those specific segments are mapped to
shadow.

Therefore, when the incoming address is converted to a shadow, we need
to add a condition to determine whether it is valid.

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Qing Zhang <zhangqing@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
 2023-09-06 22:54:16 +08:00
Enze Li
ec9fee79d4 kfence: Defer the assignment of the local variable addr 
The LoongArch architecture is different from other architectures. It
needs to update __kfence_pool during arch_kfence_init_pool().

This patch modifies the assignment location of the local variable addr
in the kfence_init_pool() function to support the case of updating
__kfence_pool in arch_kfence_init_pool().

Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Enze Li <lienze@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
 2023-09-06 22:53:55 +08:00
Linus Torvalds
3c5c9b7cfd Seven hotfixes. Four are cc:stable and the remainder pertain to issues 
which were introduced in the current merge window.
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Merge tag 'mm-hotfixes-stable-2023-09-05-11-51' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Seven hotfixes. Four are cc:stable and the remainder pertain to issues
  which were introduced in the current merge window"

* tag 'mm-hotfixes-stable-2023-09-05-11-51' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  sparc64: add missing initialization of folio in tlb_batch_add()
  mm: memory-failure: use rcu lock instead of tasklist_lock when collect_procs()
  revert "memfd: improve userspace warnings for missing exec-related flags".
  rcu: dump vmalloc memory info safely
  mm/vmalloc: add a safer version of find_vm_area() for debug
  tools/mm: fix undefined reference to pthread_once
  memcontrol: ensure memcg acquired by id is properly set up
 2023-09-05 12:22:39 -07:00
Tong Tiangen
d256d1cd8d mm: memory-failure: use rcu lock instead of tasklist_lock when collect_procs() 
We found a softlock issue in our test, analyzed the logs, and found that
the relevant CPU call trace as follows:

CPU0:
  _do_fork
    -> copy_process()
      -> write_lock_irq(&tasklist_lock)  //Disable irq,waiting for
      					 //tasklist_lock

CPU1:
  wp_page_copy()
    ->pte_offset_map_lock()
      -> spin_lock(&page->ptl);        //Hold page->ptl
    -> ptep_clear_flush()
      -> flush_tlb_others() ...
        -> smp_call_function_many()
          -> arch_send_call_function_ipi_mask()
            -> csd_lock_wait()         //Waiting for other CPUs respond
	                               //IPI

CPU2:
  collect_procs_anon()
    -> read_lock(&tasklist_lock)       //Hold tasklist_lock
      ->for_each_process(tsk)
        -> page_mapped_in_vma()
          -> page_vma_mapped_walk()
	    -> map_pte()
              ->spin_lock(&page->ptl)  //Waiting for page->ptl

We can see that CPU1 waiting for CPU0 respond IPI，CPU0 waiting for CPU2
unlock tasklist_lock, CPU2 waiting for CPU1 unlock page->ptl. As a result,
softlockup is triggered.

For collect_procs_anon(), what we're doing is task list iteration, during
the iteration, with the help of call_rcu(), the task_struct object is freed
only after one or more grace periods elapse. the logic as follows:

release_task()
  -> __exit_signal()
    -> __unhash_process()
      -> list_del_rcu()

  -> put_task_struct_rcu_user()
    -> call_rcu(&task->rcu, delayed_put_task_struct)

delayed_put_task_struct()
  -> put_task_struct()
  -> if (refcount_sub_and_test())
     	__put_task_struct()
          -> free_task()

Therefore, under the protection of the rcu lock, we can safely use
get_task_struct() to ensure a safe reference to task_struct during the
iteration.

By removing the use of tasklist_lock in task list iteration, we can break
the softlock chain above.

The same logic can also be applied to:
 - collect_procs_file()
 - collect_procs_fsdax()
 - collect_procs_ksm()

Link: https://lkml.kernel.org/r/20230828022527.241693-1-tongtiangen@huawei.com
Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-05 11:11:52 -07:00
Andrew Morton
2562d67b1b revert "memfd: improve userspace warnings for missing exec-related flags". 
This warning is telling userspace developers to pass MFD_EXEC and
MFD_NOEXEC_SEAL to memfd_create().  Commit 434ed3350f ("memfd: improve
userspace warnings for missing exec-related flags") made the warning more
frequent and visible in the hope that this would accelerate the fixing of
errant userspace.

But the overall effect is to generate far too much dmesg noise.

Fixes: 434ed3350f ("memfd: improve userspace warnings for missing exec-related flags")
Reported-by: Damian Tometzki <dtometzki@fedoraproject.org>
Closes: https://lkml.kernel.org/r/ZPFzCSIgZ4QuHsSC@fedora.fritz.box
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Daniel Verkamp <dverkamp@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-05 11:11:52 -07:00
Linus Torvalds
5eea5820c7 - Stefan Roesch has added ksm statistics to /proc/pid/smaps 
- Also a number of singleton patches, mainly cleanups and leftovers.
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Merge tag 'mm-stable-2023-09-04-14-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - Stefan Roesch has added ksm statistics to /proc/pid/smaps

 - Also a number of singleton patches, mainly cleanups and leftovers

* tag 'mm-stable-2023-09-04-14-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/kmemleak: move up cond_resched() call in page scanning loop
  mm: page_alloc: remove stale CMA guard code
  MAINTAINERS: add rmap.h to mm entry
  rmap: remove anon_vma_link() nommu stub
  proc/ksm: add ksm stats to /proc/pid/smaps
  mm/hwpoison: rename hwp_walk* to hwpoison_walk*
  mm: memory-failure: add PageOffline() check
 2023-09-05 10:56:27 -07:00
Zqiang
c83ad36a18 rcu: dump vmalloc memory info safely 
Currently, for double invoke call_rcu(), will dump rcu_head objects memory
info, if the objects is not allocated from the slab allocator, the
vmalloc_dump_obj() will be invoke and the vmap_area_lock spinlock need to
be held, since the call_rcu() can be invoked in interrupt context,
therefore, there is a possibility of spinlock deadlock scenarios.

And in Preempt-RT kernel, the rcutorture test also trigger the following
lockdep warning:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1, name: swapper/0
preempt_count: 1, expected: 0
RCU nest depth: 1, expected: 1
3 locks held by swapper/0/1:
 #0: ffffffffb534ee80 (fullstop_mutex){+.+.}-{4:4}, at: torture_init_begin+0x24/0xa0
 #1: ffffffffb5307940 (rcu_read_lock){....}-{1:3}, at: rcu_torture_init+0x1ec7/0x2370
 #2: ffffffffb536af40 (vmap_area_lock){+.+.}-{3:3}, at: find_vmap_area+0x1f/0x70
irq event stamp: 565512
hardirqs last  enabled at (565511): [<ffffffffb379b138>] __call_rcu_common+0x218/0x940
hardirqs last disabled at (565512): [<ffffffffb5804262>] rcu_torture_init+0x20b2/0x2370
softirqs last  enabled at (399112): [<ffffffffb36b2586>] __local_bh_enable_ip+0x126/0x170
softirqs last disabled at (399106): [<ffffffffb43fef59>] inet_register_protosw+0x9/0x1d0
Preemption disabled at:
[<ffffffffb58040c3>] rcu_torture_init+0x1f13/0x2370
CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W          6.5.0-rc4-rt2-yocto-preempt-rt+ #15
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x68/0xb0
 dump_stack+0x14/0x20
 __might_resched+0x1aa/0x280
 ? __pfx_rcu_torture_err_cb+0x10/0x10
 rt_spin_lock+0x53/0x130
 ? find_vmap_area+0x1f/0x70
 find_vmap_area+0x1f/0x70
 vmalloc_dump_obj+0x20/0x60
 mem_dump_obj+0x22/0x90
 __call_rcu_common+0x5bf/0x940
 ? debug_smp_processor_id+0x1b/0x30
 call_rcu_hurry+0x14/0x20
 rcu_torture_init+0x1f82/0x2370
 ? __pfx_rcu_torture_leak_cb+0x10/0x10
 ? __pfx_rcu_torture_leak_cb+0x10/0x10
 ? __pfx_rcu_torture_init+0x10/0x10
 do_one_initcall+0x6c/0x300
 ? debug_smp_processor_id+0x1b/0x30
 kernel_init_freeable+0x2b9/0x540
 ? __pfx_kernel_init+0x10/0x10
 kernel_init+0x1f/0x150
 ret_from_fork+0x40/0x50
 ? __pfx_kernel_init+0x10/0x10
 ret_from_fork_asm+0x1b/0x30
 </TASK>

The previous patch fixes this by using the deadlock-safe best-effort
version of find_vm_area.  However, in case of failure print the fact that
the pointer was a vmalloc pointer so that we print at least something.

Link: https://lkml.kernel.org/r/20230904180806.1002832-2-joel@joelfernandes.org
Fixes: 98f180837a ("mm: Make mem_dump_obj() handle vmalloc() memory")
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reported-by: Zhen Lei <thunder.leizhen@huaweicloud.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-05 10:13:45 -07:00
Joel Fernandes (Google)
0818e739b5 mm/vmalloc: add a safer version of find_vm_area() for debug 
It is unsafe to dump vmalloc area information when trying to do so from
some contexts.  Add a safer trylock version of the same function to do a
best-effort VMA finding and use it from vmalloc_dump_obj().

[applied test robot feedback on unused function fix.]
[applied Uladzislau feedback on locking.]
Link: https://lkml.kernel.org/r/20230904180806.1002832-1-joel@joelfernandes.org
Fixes: 98f180837a ("mm: Make mem_dump_obj() handle vmalloc() memory")
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reported-by: Zhen Lei <thunder.leizhen@huaweicloud.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Zqiang <qiang.zhang1211@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-05 10:13:45 -07:00
Johannes Weiner
6f0df8e16e memcontrol: ensure memcg acquired by id is properly set up 
In the eviction recency check, we attempt to retrieve the memcg to which
the folio belonged when it was evicted, by the memcg id stored in the
shadow entry.  However, there is a chance that the retrieved memcg is not
the original memcg that has been killed, but a new one which happens to
have the same id.

This is a somewhat unfortunate, but acceptable and rare inaccuracy in the
heuristics.  However, if we retrieve this new memcg between its allocation
and when it is properly attached to the memcg hierarchy, we could run into
the following NULL pointer exception during the memcg hierarchy traversal
done in mem_cgroup_get_nr_swap_pages():

[ 155757.793456] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 155757.807568] #PF: supervisor read access in kernel mode
[ 155757.818024] #PF: error_code(0x0000) - not-present page
[ 155757.828482] PGD 401f77067 P4D 401f77067 PUD 401f76067 PMD 0
[ 155757.839985] Oops: 0000 [#1] SMP
[ 155757.887870] RIP: 0010:mem_cgroup_get_nr_swap_pages+0x3d/0xb0
[ 155757.899377] Code: 29 19 4a 02 48 39 f9 74 63 48 8b 97 c0 00 00 00 48 8b b7 58 02 00 00 48 2b b7 c0 01 00 00 48 39 f0 48 0f 4d c6 48 39 d1 74 42 <48> 8b b2 c0 00 00 00 48 8b ba 58 02 00 00 48 2b ba c0 01 00 00 48
[ 155757.937125] RSP: 0018:ffffc9002ecdfbc8 EFLAGS: 00010286
[ 155757.947755] RAX: 00000000003a3b1c RBX: 000007ffffffffff RCX: ffff888280183000
[ 155757.962202] RDX: 0000000000000000 RSI: 0007ffffffffffff RDI: ffff888bbc2d1000
[ 155757.976648] RBP: 0000000000000001 R08: 000000000000000b R09: ffff888ad9cedba0
[ 155757.991094] R10: ffffea0039c07900 R11: 0000000000000010 R12: ffff888b23a7b000
[ 155758.005540] R13: 0000000000000000 R14: ffff888bbc2d1000 R15: 000007ffffc71354
[ 155758.019991] FS:  00007f6234c68640(0000) GS:ffff88903f9c0000(0000) knlGS:0000000000000000
[ 155758.036356] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 155758.048023] CR2: 00000000000000c0 CR3: 0000000a83eb8004 CR4: 00000000007706e0
[ 155758.062473] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 155758.076924] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 155758.091376] PKRU: 55555554
[ 155758.096957] Call Trace:
[ 155758.102016]  <TASK>
[ 155758.106502]  ? __die+0x78/0xc0
[ 155758.112793]  ? page_fault_oops+0x286/0x380
[ 155758.121175]  ? exc_page_fault+0x5d/0x110
[ 155758.129209]  ? asm_exc_page_fault+0x22/0x30
[ 155758.137763]  ? mem_cgroup_get_nr_swap_pages+0x3d/0xb0
[ 155758.148060]  workingset_test_recent+0xda/0x1b0
[ 155758.157133]  workingset_refault+0xca/0x1e0
[ 155758.165508]  filemap_add_folio+0x4d/0x70
[ 155758.173538]  page_cache_ra_unbounded+0xed/0x190
[ 155758.182919]  page_cache_sync_ra+0xd6/0x1e0
[ 155758.191738]  filemap_read+0x68d/0xdf0
[ 155758.199495]  ? mlx5e_napi_poll+0x123/0x940
[ 155758.207981]  ? __napi_schedule+0x55/0x90
[ 155758.216095]  __x64_sys_pread64+0x1d6/0x2c0
[ 155758.224601]  do_syscall_64+0x3d/0x80
[ 155758.232058]  entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 155758.242473] RIP: 0033:0x7f62c29153b5
[ 155758.249938] Code: e8 48 89 75 f0 89 7d f8 48 89 4d e0 e8 b4 e6 f7 ff 41 89 c0 4c 8b 55 e0 48 8b 55 e8 48 8b 75 f0 8b 7d f8 b8 11 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 33 44 89 c7 48 89 45 f8 e8 e7 e6 f7 ff 48 8b
[ 155758.288005] RSP: 002b:00007f6234c5ffd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011
[ 155758.303474] RAX: ffffffffffffffda RBX: 00007f628c4e70c0 RCX: 00007f62c29153b5
[ 155758.318075] RDX: 000000000003c041 RSI: 00007f61d2986000 RDI: 0000000000000076
[ 155758.332678] RBP: 00007f6234c5fff0 R08: 0000000000000000 R09: 0000000064d5230c
[ 155758.347452] R10: 000000000027d450 R11: 0000000000000293 R12: 000000000003c041
[ 155758.362044] R13: 00007f61d2986000 R14: 00007f629e11b060 R15: 000000000027d450
[ 155758.376661]  </TASK>

This patch fixes the issue by moving the memcg's id publication from the
alloc stage to online stage, ensuring that any memcg acquired via id must
be connected to the memcg tree.

Link: https://lkml.kernel.org/r/20230823225430.166925-1-nphamcs@gmail.com
Fixes: f78dfc7b77 ("workingset: fix confusion around eviction vs refault container")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Co-developed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-05 10:13:45 -07:00
Waiman Long
e68d343d27 mm/kmemleak: move up cond_resched() call in page scanning loop 
Commit bde5f6bc68 ("kmemleak: add scheduling point to kmemleak_scan()")
added a cond_resched() call to the struct page scanning loop to prevent
soft lockup from happening.  However, soft lockup can still happen in that
loop in some corner cases when the pages that satisfy the "!(pfn & 63)"
check are skipped for some reasons.

Fix this corner case by moving up the cond_resched() check so that it will
be called every 64 pages unconditionally.

Link: https://lkml.kernel.org/r/20230825164947.1317981-1-longman@redhat.com
Fixes: bde5f6bc68 ("kmemleak: add scheduling point to kmemleak_scan()")
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-02 15:17:34 -07:00
Johannes Weiner
f945116e4e mm: page_alloc: remove stale CMA guard code 
In the past, movable allocations could be disallowed from CMA through
PF_MEMALLOC_PIN.  As CMA pages are funneled through the MOVABLE pcplist,
this required filtering that cornercase during allocations, such that
pinnable allocations wouldn't accidentally get a CMA page.

However, since 8e3560d963 ("mm: honor PF_MEMALLOC_PIN for all movable
pages"), PF_MEMALLOC_PIN automatically excludes __GFP_MOVABLE.  Once
again, MOVABLE implies CMA is allowed.

Remove the stale filtering code.  Also remove a stale comment that was
introduced as part of the filtering code, because the filtering let
order-0 pages fall through to the buddy allocator.  See 1d91df85f3
("mm/page_alloc: handle a missing case for memalloc_nocma_{save/restore}
APIs") for context.  The comment's been obsolete since the introduction of
the explicit ALLOC_HIGHATOMIC flag in eb2e2b425c ("mm/page_alloc:
explicitly record high-order atomic allocations in alloc_flags").

Link: https://lkml.kernel.org/r/20230824153821.243148-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-02 15:17:34 -07:00
Jiaqi Yan
6885938c34 mm/hwpoison: rename hwp_walk* to hwpoison_walk* 
In the discussion of "Improve hugetlbfs read on HWPOISON hugepages" [1],
Matthew Wilcox suggests hwp is a bad abbreviation of hwpoison, as hwp is
already used as "an acronym by acpi, intel_pstate, some clock drivers, an
ethernet driver, and a scsi driver"[1].

So rename hwp_walk and hwp_walk_ops to hwpoison_walk and
hwpoison_walk_ops respectively.

raw_hwp_(page|list), *_raw_hwp, and raw_hwp_unreliable flag are other
major appearances of "hwp".  However, given the "raw" hint in the name, it
is easy to differentiate them from other "hwp" acronyms.  Since renaming
them is not as straightforward as renaming hwp_walk*, they are not covered
by this commit.

[1] https://lore.kernel.org/lkml/20230707201904.953262-5-jiaqiyan@google.com/T/#me6fecb8ce1ad4d5769199c9e162a44bc88f7bdec

Link: https://lkml.kernel.org/r/20230713235553.4121855-1-jiaqiyan@google.com
Signed-off-by: Jiaqi Yan <jiaqiyan@google.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-02 15:17:33 -07:00
Miaohe Lin
7a8817f2c9 mm: memory-failure: add PageOffline() check 
Memory failure is not interested in logically offlined pages.  Skip this
type of page.

Link: https://lkml.kernel.org/r/20230727115643.639741-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-09-02 15:17:33 -07:00
Hugh Dickins
ee40d543e9 mm/pagewalk: fix bootstopping regression from extra pte_unmap() 
Mikhail reports early-6.6-based Fedora Rawhide not booting: "rcu_preempt
detected expedited stalls", minutes wait, and then hung_task splat while
kworker trying to synchronize_rcu_expedited().  Nothing logged to disk.

He bisected to my 6.6 a349d72fd9 ("mm/pgtable: add rcu_read_lock() and
rcu_read_unlock()s"): but the one to blame is my 6.5 commit to fix the
espfix "bad pmd" warnings when booting x86_64 with CONFIG_EFI_PGT_DUMP=y.

Gaah, that added an "addr >= TASK_SIZE" check to avoid pte_offset_map(),
but failed to add the equivalent check when choosing to pte_unmap().

It's not a problem on 6.5 (for different reasons, it's harmless on both
64-bit and 32-bit), but becomes a bootstopper on 6.6 with the unbalanced
rcu_read_unlock() - RCU has a WARN_ON_ONCE for that, but it would have
scrolled off Mikhail's console too quickly.

Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Closes: https://lore.kernel.org/linux-mm/CABXGCsNi8Tiv5zUPNXr6UJw6qV1VdaBEfGqEAMkkXE3QPvZuAQ@mail.gmail.com/
Fixes: 8b1cb4a2e8 ("mm/pagewalk: fix EFI_PGT_DUMP of espfix area")
Fixes: a349d72fd9 ("mm/pgtable: add rcu_read_lock() and rcu_read_unlock()s")
Signed-off-by: Hugh Dickins <hughd@google.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2023-09-02 08:39:21 -07:00
Linus Torvalds
e987af4546 percpu: changes for v6.6 
percpu
 * A couple cleanups by Baoquan He and Bibo Mao. The only behavior change
   is to start printing messages if we're under the warn limit for failed
   atomic allocations.
 
 percpu_counter
 * Shakeel introduced percpu counters into mm_struct which caused percpu
   allocations be on the hot path [1]. Originally I spent some time
   trying to improve the percpu allocator, but instead preferred what
   Mateusz Guzik proposed grouping at the allocation site,
   percpu_counter_init_many(). This allows a single percpu allocation to
   be shared by the counters. I like this approach because it creates a
   shared lifetime by the allocations. Additionally, I believe many inits
   have higher level synchronization requirements, like percpu_counter
   does against HOTPLUG_CPU. Therefore we can group these optimizations
   together.
 
 [1] https://lore.kernel.org/linux-mm/20221024052841.3291983-1-shakeelb@google.com/
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Merge tag 'percpu-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu

Pull percpu updates from Dennis Zhou:
 "One bigger change to percpu_counter's api allowing for init and
  destroy of multiple counters via percpu_counter_init_many() and
  percpu_counter_destroy_many(). This is used to help begin remediating
  a performance regression with percpu rss stats.

  Additionally, it seems larger core count machines are feeling the
  burden of the single threaded allocation of percpu. Mateusz is
  thinking about it and I will spend some time on it too.

  percpu:

   - A couple cleanups by Baoquan He and Bibo Mao. The only behavior
     change is to start printing messages if we're under the warn limit
     for failed atomic allocations.

  percpu_counter:

   - Shakeel introduced percpu counters into mm_struct which caused
     percpu allocations be on the hot path [1]. Originally I spent some
     time trying to improve the percpu allocator, but instead preferred
     what Mateusz Guzik proposed grouping at the allocation site,
     percpu_counter_init_many(). This allows a single percpu allocation
     to be shared by the counters. I like this approach because it
     creates a shared lifetime by the allocations. Additionally, I
     believe many inits have higher level synchronization requirements,
     like percpu_counter does against HOTPLUG_CPU. Therefore we can
     group these optimizations together"

Link: https://lore.kernel.org/linux-mm/20221024052841.3291983-1-shakeelb@google.com/ [1]

* tag 'percpu-for-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
  kernel/fork: group allocation/free of per-cpu counters for mm struct
  pcpcntr: add group allocation/free
  mm/percpu.c: print error message too if atomic alloc failed
  mm/percpu.c: optimize the code in pcpu_setup_first_chunk() a little bit
  mm/percpu.c: remove redundant check
  mm/percpu: Remove some local variables in pcpu_populate_pte
 2023-09-01 15:44:45 -07:00