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1390 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Yu Zhao
|
a52dcec56c |
mm/mglru: fix PTE-mapped large folios
Count the accessed bits from PTEs mapping the same large folio as one access rather than multiple accesses. The last patch changed how folios accessed through page tables are promoted: rather than getting promoted after the accessed bit is cleared for the first time, a folio only gets promoted thereafter. Counting the accessed bits from the same large folio as multiple accesses can cause that folio to be promoted prematurely, which in turn can cause overprotection of single-use large folios. This patch reduced the sys time of the kernel compilation by 95% CI [2, 5]% on Altra M128-30 with 3GB DRAM, 12GB zram, 16KB THPs and -j32. Link: https://lkml.kernel.org/r/20241231043538.4075764-8-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reported-by: Barry Song <v-songbaohua@oppo.com> Tested-by: Kalesh Singh <kaleshsingh@google.com> Cc: Bharata B Rao <bharata@amd.com> Cc: David Stevens <stevensd@chromium.org> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yu Zhao
|
4d5d14a01e |
mm/mglru: rework workingset protection
With the aging feedback no longer considering the distribution of folios
in each generation, rework workingset protection to better distribute
folios across MAX_NR_GENS. This is achieved by reusing PG_workingset and
PG_referenced/LRU_REFS_FLAGS in a slightly different way.
For folios accessed multiple times through file descriptors, make
lru_gen_inc_refs() set additional bits of LRU_REFS_WIDTH in folio->flags
after PG_referenced, then PG_workingset after LRU_REFS_WIDTH. After all
its bits are set, i.e., LRU_REFS_FLAGS|BIT(PG_workingset), a folio is
lazily promoted into the second oldest generation in the eviction path.
And when folio_inc_gen() does that, it clears LRU_REFS_FLAGS so that
lru_gen_inc_refs() can start over. For this case, LRU_REFS_MASK is only
valid when PG_referenced is set.
For folios accessed multiple times through page tables, folio_update_gen()
from a page table walk or lru_gen_set_refs() from a rmap walk sets
PG_referenced after the accessed bit is cleared for the first time.
Thereafter, those two paths set PG_workingset and promote folios to the
youngest generation. Like folio_inc_gen(), when folio_update_gen() does
that, it also clears PG_referenced. For this case, LRU_REFS_MASK is not
used.
For both of the cases, after PG_workingset is set on a folio, it remains
until this folio is either reclaimed, or "deactivated" by
lru_gen_clear_refs(). It can be set again if lru_gen_test_recent()
returns true upon a refault.
When adding folios to the LRU lists, lru_gen_folio_seq() distributes
them as follows:
+---------------------------------+---------------------------------+
| Accessed thru page tables | Accessed thru file descriptors |
+---------------------------------+---------------------------------+
| PG_active (set while isolated) | |
+----------------+----------------+----------------+----------------+
| PG_workingset | PG_referenced | PG_workingset | LRU_REFS_FLAGS |
+---------------------------------+---------------------------------+
|<--------- MIN_NR_GENS --------->| |
|<-------------------------- MAX_NR_GENS -------------------------->|
After this patch, some typical client and server workloads showed
improvements under heavy memory pressure. For example, Python TPC-C,
which was used to benchmark a different approach [1] to better detect
refault distances, showed a significant decrease in total refaults:
Before After Change
Time (seconds) 10801 10801 0%
Executed (transactions) 41472 43663 +5%
workingset_nodes 109070 120244 +10%
workingset_refault_anon 5019627 7281831 +45%
workingset_refault_file 1294678786 554855564 -57%
workingset_refault_total 1299698413 562137395 -57%
[1] https://lore.kernel.org/20230920190244.16839-1-ryncsn@gmail.com/
Link: https://lkml.kernel.org/r/20241231043538.4075764-7-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Kairui Song <kasong@tencent.com>
Closes: https://lore.kernel.org/CAOUHufahuWcKf5f1Sg3emnqX+cODuR=2TQo7T4Gr-QYLujn4RA@mail.gmail.com/
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Bharata B Rao <bharata@amd.com>
Cc: David Stevens <stevensd@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Yu Zhao
|
37a260870f |
mm/mglru: rework type selection
With anon and file min_seq being able to move independently, rework type selection so that it is based on the total refaults from all tiers of each type. Also allow a type to be selected until that type reaches MIN_NR_GENS, regardless of whether that type has a larger min_seq or not, to accommodate extreme swappiness. Since some tiers of a selected type can have higher refaults than the first tier of the other type, use a less larger gain factor 2:3 instead of 1:2, in order for those tiers in the selected type to be better protected. As an intermediate step to the final optimization, this change by itself should not have userspace-visiable effects beyond performance. Link: https://lkml.kernel.org/r/20241231043538.4075764-5-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reported-by: David Stevens <stevensd@chromium.org> Tested-by: Kalesh Singh <kaleshsingh@google.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yu Zhao
|
798c0330c2 |
mm/mglru: rework aging feedback
The aging feedback is based on both the number of generations and the distribution of folios in each generation. The number of generations is currently the distance between max_seq and anon min_seq. This is because anon min_seq is not allowed to move past file min_seq. The rationale for that is that file is always evictable whereas anon is not. However, for use cases where anon is a lot cheaper than file: 1. Anon in the second oldest generation can be a better choice than file in the oldest generation. 2. A large amount of file in the oldest generation can skew the distribution, making should_run_aging() return false negative. Allow anon and file min_seq to move independently, and use solely the number of generations as the feedback for aging. Specifically, when both anon and file are evictable, anon min_seq can now be greater than file min_seq, and therefore the number of generations becomes the distance between max_seq and min(min_seq[0],min_seq[1]). And should_run_aging() returns true if and only if the number of generations is less than MAX_NR_GENS. As the first step to the final optimization, this change by itself should not have userspace-visiable effects beyond performance. The next twos patch will take advantage of this change; the last patch in this series will better distribute folios across MAX_NR_GENS. [yuzhao@google.com: restore behaviour for systems with swappiness == 200] Link: https://lkml.kernel.org/r/Z4S3-aJy5dj9tBTk@google.com Link: https://lkml.kernel.org/r/20241231043538.4075764-4-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reported-by: David Stevens <stevensd@chromium.org> Tested-by: Kalesh Singh <kaleshsingh@google.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
|
1d6d399223 |
Kthreads affinity follow either of 4 existing different patterns:
1) Per-CPU kthreads must stay affine to a single CPU and never execute
relevant code on any other CPU. This is currently handled by smpboot
code which takes care of CPU-hotplug operations. Affinity here is
a correctness constraint.
2) Some kthreads _have_ to be affine to a specific set of CPUs and can't
run anywhere else. The affinity is set through kthread_bind_mask()
and the subsystem takes care by itself to handle CPU-hotplug
operations. Affinity here is assumed to be a correctness constraint.
3) Per-node kthreads _prefer_ to be affine to a specific NUMA node. This
is not a correctness constraint but merely a preference in terms of
memory locality. kswapd and kcompactd both fall into this category.
The affinity is set manually like for any other task and CPU-hotplug
is supposed to be handled by the relevant subsystem so that the task
is properly reaffined whenever a given CPU from the node comes up.
Also care should be taken so that the node affinity doesn't cross
isolated (nohz_full) cpumask boundaries.
4) Similar to the previous point except kthreads have a _preferred_
affinity different than a node. Both RCU boost kthreads and RCU
exp kworkers fall into this category as they refer to "RCU nodes"
from a distinctly distributed tree.
Currently the preferred affinity patterns (3 and 4) have at least 4
identified users, with more or less success when it comes to handle
CPU-hotplug operations and CPU isolation. Each of which do it in its own
ad-hoc way.
This is an infrastructure proposal to handle this with the following API
changes:
_ kthread_create_on_node() automatically affines the created kthread to
its target node unless it has been set as per-cpu or bound with
kthread_bind[_mask]() before the first wake-up.
- kthread_affine_preferred() is a new function that can be called right
after kthread_create_on_node() to specify a preferred affinity
different than the specified node.
When the preferred affinity can't be applied because the possible
targets are offline or isolated (nohz_full), the kthread is affine
to the housekeeping CPUs (which means to all online CPUs most of the
time or only the non-nohz_full CPUs when nohz_full= is set).
kswapd, kcompactd, RCU boost kthreads and RCU exp kworkers have been
converted, along with a few old drivers.
Summary of the changes:
* Consolidate a bunch of ad-hoc implementations of kthread_run_on_cpu()
* Introduce task_cpu_fallback_mask() that defines the default last
resort affinity of a task to become nohz_full aware
* Add some correctness check to ensure kthread_bind() is always called
before the first kthread wake up.
* Default affine kthread to its preferred node.
* Convert kswapd / kcompactd and remove their halfway working ad-hoc
affinity implementation
* Implement kthreads preferred affinity
* Unify kthread worker and kthread API's style
* Convert RCU kthreads to the new API and remove the ad-hoc affinity
implementation.
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Merge tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"Kthreads affinity follow either of 4 existing different patterns:
1) Per-CPU kthreads must stay affine to a single CPU and never
execute relevant code on any other CPU. This is currently handled
by smpboot code which takes care of CPU-hotplug operations.
Affinity here is a correctness constraint.
2) Some kthreads _have_ to be affine to a specific set of CPUs and
can't run anywhere else. The affinity is set through
kthread_bind_mask() and the subsystem takes care by itself to
handle CPU-hotplug operations. Affinity here is assumed to be a
correctness constraint.
3) Per-node kthreads _prefer_ to be affine to a specific NUMA node.
This is not a correctness constraint but merely a preference in
terms of memory locality. kswapd and kcompactd both fall into this
category. The affinity is set manually like for any other task and
CPU-hotplug is supposed to be handled by the relevant subsystem so
that the task is properly reaffined whenever a given CPU from the
node comes up. Also care should be taken so that the node affinity
doesn't cross isolated (nohz_full) cpumask boundaries.
4) Similar to the previous point except kthreads have a _preferred_
affinity different than a node. Both RCU boost kthreads and RCU
exp kworkers fall into this category as they refer to "RCU nodes"
from a distinctly distributed tree.
Currently the preferred affinity patterns (3 and 4) have at least 4
identified users, with more or less success when it comes to handle
CPU-hotplug operations and CPU isolation. Each of which do it in its
own ad-hoc way.
This is an infrastructure proposal to handle this with the following
API changes:
- kthread_create_on_node() automatically affines the created kthread
to its target node unless it has been set as per-cpu or bound with
kthread_bind[_mask]() before the first wake-up.
- kthread_affine_preferred() is a new function that can be called
right after kthread_create_on_node() to specify a preferred
affinity different than the specified node.
When the preferred affinity can't be applied because the possible
targets are offline or isolated (nohz_full), the kthread is affine to
the housekeeping CPUs (which means to all online CPUs most of the time
or only the non-nohz_full CPUs when nohz_full= is set).
kswapd, kcompactd, RCU boost kthreads and RCU exp kworkers have been
converted, along with a few old drivers.
Summary of the changes:
- Consolidate a bunch of ad-hoc implementations of
kthread_run_on_cpu()
- Introduce task_cpu_fallback_mask() that defines the default last
resort affinity of a task to become nohz_full aware
- Add some correctness check to ensure kthread_bind() is always
called before the first kthread wake up.
- Default affine kthread to its preferred node.
- Convert kswapd / kcompactd and remove their halfway working ad-hoc
affinity implementation
- Implement kthreads preferred affinity
- Unify kthread worker and kthread API's style
- Convert RCU kthreads to the new API and remove the ad-hoc affinity
implementation"
* tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks:
kthread: modify kernel-doc function name to match code
rcu: Use kthread preferred affinity for RCU exp kworkers
treewide: Introduce kthread_run_worker[_on_cpu]()
kthread: Unify kthread_create_on_cpu() and kthread_create_worker_on_cpu() automatic format
rcu: Use kthread preferred affinity for RCU boost
kthread: Implement preferred affinity
mm: Create/affine kswapd to its preferred node
mm: Create/affine kcompactd to its preferred node
kthread: Default affine kthread to its preferred NUMA node
kthread: Make sure kthread hasn't started while binding it
sched,arm64: Handle CPU isolation on last resort fallback rq selection
arm64: Exclude nohz_full CPUs from 32bits el0 support
lib: test_objpool: Use kthread_run_on_cpu()
kallsyms: Use kthread_run_on_cpu()
soc/qman: test: Use kthread_run_on_cpu()
arm/bL_switcher: Use kthread_run_on_cpu()
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Donet Tom
|
bd3d56ffa2 |
mm: vmscan : pgdemote vmstat is not getting updated when MGLRU is enabled.
When MGLRU is enabled, the pgdemote_kswapd, pgdemote_direct, and pgdemote_khugepaged stats in vmstat are not being updated. Commit |
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Frederic Weisbecker
|
c6a566f6c1 |
mm: Create/affine kswapd to its preferred node
kswapd is dedicated to a specific node. As such it wants to be preferrably affine to it, memory and CPUs-wise. Use the proper kthread API to achieve that. As a bonus it takes care of CPU-hotplug events and CPU-isolation on its behalf. Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> |
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Seiji Nishikawa
|
6aaced5abd |
mm: vmscan: account for free pages to prevent infinite Loop in throttle_direct_reclaim()
The task sometimes continues looping in throttle_direct_reclaim() because
allow_direct_reclaim(pgdat) keeps returning false.
#0 [ffff80002cb6f8d0] __switch_to at ffff8000080095ac
#1 [ffff80002cb6f900] __schedule at ffff800008abbd1c
#2 [ffff80002cb6f990] schedule at ffff800008abc50c
#3 [ffff80002cb6f9b0] throttle_direct_reclaim at ffff800008273550
#4 [ffff80002cb6fa20] try_to_free_pages at ffff800008277b68
#5 [ffff80002cb6fae0] __alloc_pages_nodemask at ffff8000082c4660
#6 [ffff80002cb6fc50] alloc_pages_vma at ffff8000082e4a98
#7 [ffff80002cb6fca0] do_anonymous_page at ffff80000829f5a8
#8 [ffff80002cb6fce0] __handle_mm_fault at ffff8000082a5974
#9 [ffff80002cb6fd90] handle_mm_fault at ffff8000082a5bd4
At this point, the pgdat contains the following two zones:
NODE: 4 ZONE: 0 ADDR: ffff00817fffe540 NAME: "DMA32"
SIZE: 20480 MIN/LOW/HIGH: 11/28/45
VM_STAT:
NR_FREE_PAGES: 359
NR_ZONE_INACTIVE_ANON: 18813
NR_ZONE_ACTIVE_ANON: 0
NR_ZONE_INACTIVE_FILE: 50
NR_ZONE_ACTIVE_FILE: 0
NR_ZONE_UNEVICTABLE: 0
NR_ZONE_WRITE_PENDING: 0
NR_MLOCK: 0
NR_BOUNCE: 0
NR_ZSPAGES: 0
NR_FREE_CMA_PAGES: 0
NODE: 4 ZONE: 1 ADDR: ffff00817fffec00 NAME: "Normal"
SIZE: 8454144 PRESENT: 98304 MIN/LOW/HIGH: 68/166/264
VM_STAT:
NR_FREE_PAGES: 146
NR_ZONE_INACTIVE_ANON: 94668
NR_ZONE_ACTIVE_ANON: 3
NR_ZONE_INACTIVE_FILE: 735
NR_ZONE_ACTIVE_FILE: 78
NR_ZONE_UNEVICTABLE: 0
NR_ZONE_WRITE_PENDING: 0
NR_MLOCK: 0
NR_BOUNCE: 0
NR_ZSPAGES: 0
NR_FREE_CMA_PAGES: 0
In allow_direct_reclaim(), while processing ZONE_DMA32, the sum of
inactive/active file-backed pages calculated in zone_reclaimable_pages()
based on the result of zone_page_state_snapshot() is zero.
Additionally, since this system lacks swap, the calculation of inactive/
active anonymous pages is skipped.
crash> p nr_swap_pages
nr_swap_pages = $1937 = {
counter = 0
}
As a result, ZONE_DMA32 is deemed unreclaimable and skipped, moving on to
the processing of the next zone, ZONE_NORMAL, despite ZONE_DMA32 having
free pages significantly exceeding the high watermark.
The problem is that the pgdat->kswapd_failures hasn't been incremented.
crash> px ((struct pglist_data *) 0xffff00817fffe540)->kswapd_failures
$1935 = 0x0
This is because the node deemed balanced. The node balancing logic in
balance_pgdat() evaluates all zones collectively. If one or more zones
(e.g., ZONE_DMA32) have enough free pages to meet their watermarks, the
entire node is deemed balanced. This causes balance_pgdat() to exit early
before incrementing the kswapd_failures, as it considers the overall
memory state acceptable, even though some zones (like ZONE_NORMAL) remain
under significant pressure.
The patch ensures that zone_reclaimable_pages() includes free pages
(NR_FREE_PAGES) in its calculation when no other reclaimable pages are
available (e.g., file-backed or anonymous pages). This change prevents
zones like ZONE_DMA32, which have sufficient free pages, from being
mistakenly deemed unreclaimable. By doing so, the patch ensures proper
node balancing, avoids masking pressure on other zones like ZONE_NORMAL,
and prevents infinite loops in throttle_direct_reclaim() caused by
allow_direct_reclaim(pgdat) repeatedly returning false.
The kernel hangs due to a task stuck in throttle_direct_reclaim(), caused
by a node being incorrectly deemed balanced despite pressure in certain
zones, such as ZONE_NORMAL. This issue arises from
zone_reclaimable_pages() returning 0 for zones without reclaimable file-
backed or anonymous pages, causing zones like ZONE_DMA32 with sufficient
free pages to be skipped.
The lack of swap or reclaimable pages results in ZONE_DMA32 being ignored
during reclaim, masking pressure in other zones. Consequently,
pgdat->kswapd_failures remains 0 in balance_pgdat(), preventing fallback
mechanisms in allow_direct_reclaim() from being triggered, leading to an
infinite loop in throttle_direct_reclaim().
This patch modifies zone_reclaimable_pages() to account for free pages
(NR_FREE_PAGES) when no other reclaimable pages exist. This ensures zones
with sufficient free pages are not skipped, enabling proper balancing and
reclaim behavior.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/20241130164346.436469-1-snishika@redhat.com
Link: https://lkml.kernel.org/r/20241130161236.433747-2-snishika@redhat.com
Fixes:
|
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Zeng Jingxiang
|
1bc542c6a0 |
mm/vmscan: wake up flushers conditionally to avoid cgroup OOM
Commit |
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Shakeel Butt
|
cf4a65539c |
memcg-v1: no need for memcg locking for MGLRU
While updating the generation of the folios, MGLRU requires that the folio's memcg association remains stable. With the charge migration deprecated, there is no need for MGLRU to acquire locks to keep the folio and memcg association stable. [yuzhao@google.com: remove !rcu_read_lock_held() assertion] Link: https://lkml.kernel.org/r/ZykEtcHrQRq-KrBC@google.com Link: https://syzkaller.appspot.com/bug?extid=24f45b8beab9788e467e Link: https://lore.kernel.org/lkml/67294349.050a0220.701a.0010.GAE@google.com/ [akpm@linux-foundation.org: remove now-unused local] [shakeel.butt@linux.dev: folio_rcu() fixup, per Yu Zhao] Link: https://lkml.kernel.org/r/iwmabnye3nl4merealrawt3bdvfii2pwavwrddrqpraoveet7h@ezrsdhjwwej7 Link: https://lkml.kernel.org/r/20241025012304.2473312-6-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Wei Xu
|
f1001f3d3b |
mm/mglru: reset page lru tier bits when activating
When a folio is activated, lru_gen_add_folio() moves the folio to the
youngest generation. But unlike folio_update_gen()/folio_inc_gen(),
lru_gen_add_folio() doesn't reset the folio lru tier bits (LRU_REFS_MASK |
LRU_REFS_FLAGS). This inconsistency can affect how pages are aged via
folio_mark_accessed() (e.g. fd accesses), though no user visible impact
related to this has been detected yet.
Note that lru_gen_add_folio() cannot clear PG_workingset if the activation
is due to workingset refault, otherwise PSI accounting will be skipped.
So fix lru_gen_add_folio() to clear the lru tier bits other than
PG_workingset when activating a folio, and also clear all the lru tier
bits when a folio is activated via folio_activate() in
lru_gen_look_around().
Link: https://lkml.kernel.org/r/20241017181528.3358821-1-weixugc@google.com
Fixes:
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Jaewon Kim
|
1f2d03cc53 |
vmscan: add a vmscan event for reclaim_pages
reclaim_folio_list uses a dummy reclaim_stat and is not being used. To know the memory stat, add a new trace event. This is useful how how many pages are not reclaimed or why. This is an example: mm_vmscan_reclaim_pages: nid=0 nr_scanned=112 nr_reclaimed=112 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0 Currently reclaim_folio_list is only called by reclaim_pages, and reclaim_pages is used by damon and madvise. In the latest Android, reclaim_pages is also used by shmem to reclaim all pages in a address_space. [jaewon31.kim@samsung.com: use sc.nr_scanned rather than new counting] Link: https://lkml.kernel.org/r/20241016143227.961162-1-jaewon31.kim@samsung.com Link: https://lkml.kernel.org/r/20241011124928.1224813-1-jaewon31.kim@samsung.com Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jaewon Kim <jaewon31.kim@samsung.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kanchana P Sridhar
|
e26060d1fb |
mm: swap: make some count_mthp_stat() call-sites be THP-agnostic.
In commit
|
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Qi Zheng
|
2441774f2d |
mm: multi-gen LRU: walk_pte_range() use pte_offset_map_rw_nolock()
In walk_pte_range(), we may modify the pte entry after holding the ptl, so convert it to using pte_offset_map_rw_nolock(). At this time, the pte_same() check is not performed after the ptl held, so we should get pmdval and do pmd_same() check to ensure the stability of pmd entry. Link: https://lkml.kernel.org/r/7e9c194a5efacc9609cfd31abb9c7df88b53b530.1727332572.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Zhiguo Jiang
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bbc251f30e |
mm: fix shrink nr.unqueued_dirty counter issue
It is needed to ensure sc->nr.unqueued_dirty > 0, which can avoid setting PGDAT_DIRTY flag when sc->nr.unqueued_dirty and sc->nr.file_taken are both zero. Link: https://lkml.kernel.org/r/20240112012353.1387-1-justinjiang@vivo.com Signed-off-by: Zhiguo Jiang <justinjiang@vivo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
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f8f931bba0 |
mm/thp: fix deferred split unqueue naming and locking
Recent changes are putting more pressure on THP deferred split queues: under load revealing long-standing races, causing list_del corruptions, "Bad page state"s and worse (I keep BUGs in both of those, so usually don't get to see how badly they end up without). The relevant recent changes being 6.8's mTHP, 6.10's mTHP swapout, and 6.12's mTHP swapin, improved swap allocation, and underused THP splitting. Before fixing locking: rename misleading folio_undo_large_rmappable(), which does not undo large_rmappable, to folio_unqueue_deferred_split(), which is what it does. But that and its out-of-line __callee are mm internals of very limited usability: add comment and WARN_ON_ONCEs to check usage; and return a bool to say if a deferred split was unqueued, which can then be used in WARN_ON_ONCEs around safety checks (sparing callers the arcane conditionals in __folio_unqueue_deferred_split()). Just omit the folio_unqueue_deferred_split() from free_unref_folios(), all of whose callers now call it beforehand (and if any forget then bad_page() will tell) - except for its caller put_pages_list(), which itself no longer has any callers (and will be deleted separately). Swapout: mem_cgroup_swapout() has been resetting folio->memcg_data 0 without checking and unqueueing a THP folio from deferred split list; which is unfortunate, since the split_queue_lock depends on the memcg (when memcg is enabled); so swapout has been unqueueing such THPs later, when freeing the folio, using the pgdat's lock instead: potentially corrupting the memcg's list. __remove_mapping() has frozen refcount to 0 here, so no problem with calling folio_unqueue_deferred_split() before resetting memcg_data. That goes back to 5.4 commit |
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Yu Zhao
|
1d4832becd |
mm: multi-gen LRU: use {ptep,pmdp}_clear_young_notify()
When the MM_WALK capability is enabled, memory that is mostly accessed by
a VM appears younger than it really is, therefore this memory will be less
likely to be evicted. Therefore, the presence of a running VM can
significantly increase swap-outs for non-VM memory, regressing the
performance for the rest of the system.
Fix this regression by always calling {ptep,pmdp}_clear_young_notify()
whenever we clear the young bits on PMDs/PTEs.
[jthoughton@google.com: fix link-time error]
Link: https://lkml.kernel.org/r/20241019012940.3656292-3-jthoughton@google.com
Fixes:
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Yu Zhao
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ddd6d8e975 |
mm: multi-gen LRU: remove MM_LEAF_OLD and MM_NONLEAF_TOTAL stats
Patch series "mm: multi-gen LRU: Have secondary MMUs participate in
MM_WALK".
Today, the MM_WALK capability causes MGLRU to clear the young bit from
PMDs and PTEs during the page table walk before eviction, but MGLRU does
not call the clear_young() MMU notifier in this case. By not calling this
notifier, the MM walk takes less time/CPU, but it causes pages that are
accessed mostly through KVM / secondary MMUs to appear younger than they
should be.
We do call the clear_young() notifier today, but only when attempting to
evict the page, so we end up clearing young/accessed information less
frequently for secondary MMUs than for mm PTEs, and therefore they appear
younger and are less likely to be evicted. Therefore, memory that is
*not* being accessed mostly by KVM will be evicted *more* frequently,
worsening performance.
ChromeOS observed a tab-open latency regression when enabling MGLRU with a
setup that involved running a VM:
Tab-open latency histogram (ms)
Version p50 mean p95 p99 max
base 1315 1198 2347 3454 10319
mglru 2559 1311 7399 12060 43758
fix 1119 926 2470 4211 6947
This series replaces the final non-selftest patchs from this series[1],
which introduced a similar change (and a new MMU notifier) with KVM
optimizations. I'll send a separate series (to Sean and Paolo) for the
KVM optimizations.
This series also makes proactive reclaim with MGLRU possible for KVM
memory. I have verified that this functions correctly with the selftest
from [1], but given that that test is a KVM selftest, I'll send it with
the rest of the KVM optimizations later. Andrew, let me know if you'd
like to take the test now anyway.
[1]: https://lore.kernel.org/linux-mm/20240926013506.860253-18-jthoughton@google.com/
This patch (of 2):
The removed stats, MM_LEAF_OLD and MM_NONLEAF_TOTAL, are not very helpful
and become more complicated to properly compute when adding
test/clear_young() notifiers in MGLRU's mm walk.
Link: https://lkml.kernel.org/r/20241019012940.3656292-1-jthoughton@google.com
Link: https://lkml.kernel.org/r/20241019012940.3656292-2-jthoughton@google.com
Fixes:
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Wei Xu
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b130ba4a62 |
mm/mglru: only clear kswapd_failures if reclaimable
lru_gen_shrink_node() unconditionally clears kswapd_failures, which can
prevent kswapd from sleeping and cause 100% kswapd cpu usage even when
kswapd repeatedly fails to make progress in reclaim.
Only clear kswap_failures in lru_gen_shrink_node() if reclaim makes some
progress, similar to shrink_node().
I happened to run into this problem in one of my tests recently. It
requires a combination of several conditions: The allocator needs to
allocate a right amount of pages such that it can wake up kswapd
without itself being OOM killed; there is no memory for kswapd to
reclaim (My test disables swap and cleans page cache first); no other
process frees enough memory at the same time.
Link: https://lkml.kernel.org/r/20241014221211.832591-1-weixugc@google.com
Fixes:
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Linus Torvalds
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617a814f14 |
ALong with the usual shower of singleton patches, notable patch series in
this pull request are:
"Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
"Some cleanups for shmem" from Baolin Wang. No functional changes - mode
code reuse, better function naming, logic simplifications.
"mm: some small page fault cleanups" from Josef Bacik. No functional
changes - code cleanups only.
"Various memory tiering fixes" from Zi Yan. A small fix and a little
cleanup.
"mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
"Kernel stack usage histogram" from Pasha Tatashin and Shakeel Butt. This
is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at all
used 16k. Useful for some system tuning things, but partivularly useful
for "the dynamic kernel stack project".
"kmemleak: support for percpu memory leak detect" from Pavel Tikhomirov.
Teaches kmemleak to detect leaksage of percpu memory.
"mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
"mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from David
Hildenbrand. Improves PTE/PMD splitlock detection, makes powerpc/8xx work
correctly by design rather than by accident.
"mm: remove arch_make_page_accessible()" from David Hildenbrand. Some
folio conversions which make arch_make_page_accessible() unneeded.
"mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David Finkel.
Cleans up and fixes our handling of the resetting of the cgroup/process
peak-memory-use detector.
"Make core VMA operations internal and testable" from Lorenzo Stoakes.
Rationalizaion and encapsulation of the VMA manipulation APIs. With a
view to better enable testing of the VMA functions, even from a
userspace-only harness.
"mm: zswap: fixes for global shrinker" from Takero Funaki. Fix issues in
the zswap global shrinker, resulting in improved performance.
"mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill in
some missing info in /proc/zoneinfo.
"mm: replace follow_page() by folio_walk" from David Hildenbrand. Code
cleanups and rationalizations (conversion to folio_walk()) resulting in
the removal of follow_page().
"improving dynamic zswap shrinker protection scheme" from Nhat Pham. Some
tuning to improve zswap's dynamic shrinker. Significant reductions in
swapin and improvements in performance are shown.
"mm: Fix several issues with unaccepted memory" from Kirill Shutemov.
Improvements to the new unaccepted memory feature,
"mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on DAX
PUDs. This was missing, although nobody seems to have notied yet.
"Introduce a store type enum for the Maple tree" from Sidhartha Kumar.
Cleanups and modest performance improvements for the maple tree library
code.
"memcg: further decouple v1 code from v2" from Shakeel Butt. Move more
cgroup v1 remnants away from the v2 memcg code.
"memcg: initiate deprecation of v1 features" from Shakeel Butt. Adds
various warnings telling users that memcg v1 features are deprecated.
"mm: swap: mTHP swap allocator base on swap cluster order" from Chris Li.
Greatly improves the success rate of the mTHP swap allocation.
"mm: introduce numa_memblks" from Mike Rapoport. Moves various disparate
per-arch implementations of numa_memblk code into generic code.
"mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
"support large folio swap-out and swap-in for shmem" from Baolin Wang.
With this series we no longer split shmem large folios into simgle-page
folios when swapping out shmem.
"mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice performance
improvements and code reductions for gigantic folios.
"support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
"mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
"Increase the number of bits available in page_type" from Matthew Wilcox.
Increases the number of bits available in page_type!
"Simplify the page flags a little" from Matthew Wilcox. Many legacy page
flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
"mm: store zero pages to be swapped out in a bitmap" from Usama Arif. An
optimization which permits us to avoid writing/reading zero-filled zswap
pages to backing store.
"Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race window
which occurs when a MAP_FIXED operqtion is occurring during an unrelated
vma tree walk.
"mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of the
vma_merge() functionality, making ot cleaner, more testable and better
tested.
"misc fixups for DAMON {self,kunit} tests" from SeongJae Park. Minor
fixups of DAMON selftests and kunit tests.
"mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang. Code
cleanups and folio conversions.
"Shmem mTHP controls and stats improvements" from Ryan Roberts. Cleanups
for shmem controls and stats.
"mm: count the number of anonymous THPs per size" from Barry Song. Expose
additional anon THP stats to userspace for improved tuning.
"mm: finish isolate/putback_lru_page()" from Kefeng Wang: more folio
conversions and removal of now-unused page-based APIs.
"replace per-quota region priorities histogram buffer with per-context
one" from SeongJae Park. DAMON histogram rationalization.
"Docs/damon: update GitHub repo URLs and maintainer-profile" from SeongJae
Park. DAMON documentation updates.
"mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and improve
related doc and warn" from Jason Wang: fixes usage of page allocator
__GFP_NOFAIL and GFP_ATOMIC flags.
"mm: split underused THPs" from Yu Zhao. Improve THP=always policy - this
was overprovisioning THPs in sparsely accessed memory areas.
"zram: introduce custom comp backends API" frm Sergey Senozhatsky. Add
support for zram run-time compression algorithm tuning.
"mm: Care about shadow stack guard gap when getting an unmapped area" from
Mark Brown. Fix up the various arch_get_unmapped_area() implementations
to better respect guard areas.
"Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability of
mem_cgroup_iter() and various code cleanups.
"mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
"resource: Fix region_intersects() vs add_memory_driver_managed()" from
Huang Ying. Fix a bug in region_intersects() for systems with CXL memory.
"mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches a
couple more code paths to correctly recover from the encountering of
poisoned memry.
"mm: enable large folios swap-in support" from Barry Song. Support the
swapin of mTHP memory into appropriately-sized folios, rather than into
single-page folios.
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Merge tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:
- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.
- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.
- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.
- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".
- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.
- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.
- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.
- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.
- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.
- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.
- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.
- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().
- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.
- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,
- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.
- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.
- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.
- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.
- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.
- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.
- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.
- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.
- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!
- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.
- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.
- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.
- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.
- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.
- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.
- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.
- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.
- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.
- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.
- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.
- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.
- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.
- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.
- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.
- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.
- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.
- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"
* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...
|
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|
Usama Arif
|
8422acdc97 |
mm: introduce a pageflag for partially mapped folios
Currently folio->_deferred_list is used to keep track of partially_mapped folios that are going to be split under memory pressure. In the next patch, all THPs that are faulted in and collapsed by khugepaged are also going to be tracked using _deferred_list. This patch introduces a pageflag to be able to distinguish between partially mapped folios and others in the deferred_list at split time in deferred_split_scan. Its needed as __folio_remove_rmap decrements _mapcount, _large_mapcount and _entire_mapcount, hence it won't be possible to distinguish between partially mapped folios and others in deferred_split_scan. Eventhough it introduces an extra flag to track if the folio is partially mapped, there is no functional change intended with this patch and the flag is not useful in this patch itself, it will become useful in the next patch when _deferred_list has non partially mapped folios. Link: https://lkml.kernel.org/r/20240830100438.3623486-5-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Cc: Alexander Zhu <alexlzhu@fb.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kairui Song <ryncsn@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nico Pache <npache@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shuang Zhai <zhais@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Shuang Zhai <szhai2@cs.rochester.edu> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Chris Li
|
0885ef4705 |
mm: vmscan.c: fix OOM on swap stress test
I found a regression on mm-unstable during my swap stress test, using tmpfs to compile linux. The test OOM very soon after the make spawns many cc processes. It bisects down to this change: |
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|
Kaiyang Zhao
|
f77f0c7514 |
mm,memcg: provide per-cgroup counters for NUMA balancing operations
The ability to observe the demotion and promotion decisions made by the kernel on a per-cgroup basis is important for monitoring and tuning containerized workloads on machines equipped with tiered memory. Different containers in the system may experience drastically different memory tiering actions that cannot be distinguished from the global counters alone. For example, a container running a workload that has a much hotter memory accesses will likely see more promotions and fewer demotions, potentially depriving a colocated container of top tier memory to such an extent that its performance degrades unacceptably. For another example, some containers may exhibit longer periods between data reuse, causing much more numa_hint_faults than numa_pages_migrated. In this case, tuning hot_threshold_ms may be appropriate, but the signal can easily be lost if only global counters are available. In the long term, we hope to introduce per-cgroup control of promotion and demotion actions to implement memory placement policies in tiering. This patch set adds seven counters to memory.stat in a cgroup: numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd, pgdemote_khugepaged, pgdemote_direct and pgpromote_success. pgdemote_* and pgpromote_success are also available in memory.numa_stat. count_memcg_events_mm() is added to count multiple event occurrences at once, and get_mem_cgroup_from_folio() is added because we need to get a reference to the memcg of a folio before it's migrated to track numa_pages_migrated. The accounting of PGDEMOTE_* is moved to shrink_inactive_list() before being changed to per-cgroup. [kaiyang2@cs.cmu.edu: add documentation of the memcg counters in cgroup-v2.rst] Link: https://lkml.kernel.org/r/20240814235122.252309-1-kaiyang2@cs.cmu.edu Link: https://lkml.kernel.org/r/20240814174227.30639-1-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Baolin Wang
|
809bc86517 |
mm: shmem: support large folio swap out
Shmem will support large folio allocation [1] [2] to get a better performance, however, the memory reclaim still splits the precious large folios when trying to swap out shmem, which may lead to the memory fragmentation issue and can not take advantage of the large folio for shmeme. Moreover, the swap code already supports for swapping out large folio without split, hence this patch set supports the large folio swap out for shmem. Note the i915_gem_shmem driver still need to be split when swapping, thus add a new flag 'split_large_folio' for writeback_control to indicate spliting the large folio. [1] https://lore.kernel.org/all/cover.1717495894.git.baolin.wang@linux.alibaba.com/ [2] https://lore.kernel.org/all/20240515055719.32577-1-da.gomez@samsung.com/ [hughd@google.com: shmem_writepage() split folio at EOF before swapout] Link: https://lkml.kernel.org/r/aef55f8d-6040-692d-65e3-16150cce4440@google.com [baolin.wang@linux.alibaba.com: remove the wbc->split_large_folio per Hugh] Link: https://lkml.kernel.org/r/1236a002daa301b3b9ba73d6c0fab348427cf295.1724833399.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/d80c21abd20e1b0f5ca66b330f074060fb2f082d.1723434324.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pankaj Raghav <p.raghav@samsung.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Shakeel Butt
|
90a6f2a8f4 |
memcg: use ratelimited stats flush in the reclaim
The Meta prod is seeing large amount of stalls in memcg stats flush from the memcg reclaim code path. At the moment, this specific callsite is doing a synchronous memcg stats flush. The rstat flush is an expensive and time consuming operation, so concurrent relaimers will busywait on the lock potentially for a long time. Actually this issue is not unique to Meta and has been observed by Cloudflare [1] as well. For the Cloudflare case, the stalls were due to contention between kswapd threads running on their 8 numa node machines which does not make sense as rstat flush is global and flush from one kswapd thread should be sufficient for all. Simply replace the synchronous flush with the ratelimited one. One may raise a concern on potentially using 2 sec stale (at worst) stats for heuristics like desirable inactive:active ratio and preferring inactive file pages over anon pages but these specific heuristics do not require very precise stats and also are ignored under severe memory pressure. More specifically for this code path, the stats are needed for two specific heuristics: 1. Deactivate LRUs 2. Cache trim mode The deactivate LRUs heuristic is to maintain a desirable inactive:active ratio of the LRUs. The specific stats needed are WORKINGSET_ACTIVATE* and the hierarchical LRU size. The WORKINGSET_ACTIVATE* is needed to check if there is a refault since last snapshot and the LRU size are needed for the desirable ratio between inactive and active LRUs. See the table below on how the desirable ratio is calculated. /* total target max * memory ratio inactive * ------------------------------------- * 10MB 1 5MB * 100MB 1 50MB * 1GB 3 250MB * 10GB 10 0.9GB * 100GB 31 3GB * 1TB 101 10GB * 10TB 320 32GB */ The desirable ratio only changes at the boundary of 1 GiB, 10 GiB, 100 GiB, 1 TiB and 10 TiB. There is no need for the precise and accurate LRU size information to calculate this ratio. In addition, if deactivation is skipped for some LRU, the kernel will force deactive on the severe memory pressure situation. For the cache trim mode, inactive file LRU size is read and the kernel scales it down based on the reclaim iteration (file >> sc->priority) and only checks if it is zero or not. Again precise information is not needed. This patch has been running on Meta fleet for several months and we have not observed any issues. Please note that MGLRU is not impacted by this issue at all as it avoids rstat flushing completely. Link: https://lore.kernel.org/all/6ee2518b-81dd-4082-bdf5-322883895ffc@kernel.org [1] Link: https://lkml.kernel.org/r/20240813215358.2259750-1-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Jesper Dangaard Brouer <hawk@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Yuanchu Xie
|
bceeeaed48 |
mm: multi-gen LRU: ignore non-leaf pmd_young for force_scan=true
When non-leaf pmd accessed bits are available, MGLRU page table walks can clear the non-leaf pmd accessed bit and ignore the accessed bit on the pte if it's on a different node, skipping a generation update as well. If another scan occurs on the same node as said skipped pte. The non-leaf pmd accessed bit might remain cleared and the pte accessed bits won't be checked. While this is sufficient for reclaim-driven aging, where the goal is to select a reasonably cold page, the access can be missed when aging proactively for workingset estimation of a node/memcg. In more detail, get_pfn_folio returns NULL if the folio's nid != node under scanning, so the page table walk skips processing of said pte. Now the pmd_young flag on this pmd is cleared, and if none of the pte's are accessed before another scan occurs on the folio's node, the pmd_young check fails and the pte accessed bit is skipped. Since force_scan disables various other optimizations, we check force_scan to ignore the non-leaf pmd accessed bit. Link: https://lkml.kernel.org/r/20240813163759.742675-1-yuanchu@google.com Signed-off-by: Yuanchu Xie <yuanchu@google.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Lance Yang <ioworker0@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
8710f6ed34 |
mm/huge_memory: convert split_huge_pages_pid() from follow_page() to folio_walk
Let's remove yet another follow_page() user. Note that we have to do the split without holding the PTL, after folio_walk_end(). We don't care about losing the secretmem check in follow_page(). [david@redhat.com: teach can_split_folio() that we are not holding an additional reference] Link: https://lkml.kernel.org/r/c75d1c6c-8ea6-424f-853c-1ccda6c77ba2@redhat.com Link: https://lkml.kernel.org/r/20240802155524.517137-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Kaiyang Zhao
|
03790c51a4 |
mm: create promo_wmark_pages and clean up open-coded sites
Patch series "mm: print the promo watermark in zoneinfo", v2. This patch (of 2): Define promo_wmark_pages and convert current call sites of wmark_pages with fixed WMARK_PROMO to using it instead. Link: https://lkml.kernel.org/r/20240801232548.36604-1-kaiyang2@cs.cmu.edu Link: https://lkml.kernel.org/r/20240801232548.36604-2-kaiyang2@cs.cmu.edu Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Zhiguo Jiang
|
c495b97624 |
mm: shrink skip folio mapped by an exiting process
The releasing process of the non-shared anonymous folio mapped solely by an exiting process may go through two flows: 1) the anonymous folio is firstly is swaped-out into swapspace and transformed into a swp_entry in shrink_folio_list; 2) then the swp_entry is released in the process exiting flow. This will result in the high cpu load of releasing a non-shared anonymous folio mapped solely by an exiting process. When the low system memory and the exiting process exist at the same time, it will be likely to happen, because the non-shared anonymous folio mapped solely by an exiting process may be reclaimed by shrink_folio_list. This patch is that shrink skips the non-shared anonymous folio solely mapped by an exting process and this folio is only released directly in the process exiting flow, which will save swap-out time and alleviate the load of the process exiting. Barry provided some effectiveness testing in [1]. "I observed that this patch effectively skipped 6114 folios (either 4KB or 64KB mTHP), potentially reducing the swap-out by up to 92MB (97,300,480 bytes) during the process exit. The working set size is 256MB." Link: https://lkml.kernel.org/r/20240710083641.546-1-justinjiang@vivo.com Link: https://lore.kernel.org/linux-mm/20240710033212.36497-1-21cnbao@gmail.com/ [1] Signed-off-by: Zhiguo Jiang <justinjiang@vivo.com> Acked-by: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Cassell
|
5fe690a594 |
mm: add node_reclaim successes to VM event counters
/proc/vmstat currently shows the number of node_reclaim() failures when vm.zone_reclaim_mode is set appropriately. It would be convenient to have the number of successes right next to zone_reclaim_failed (similar to compaction and migration). While just a trivially addition to the vmstat file. It was helpful during benchmarking to not have to probe node_reclaim() to observe the success/failure ratio. Link: https://lkml.kernel.org/r/20240722171316.7517-1-mcassell411@gmail.com Signed-off-by: Matthew Cassell <mcassell411@gmail.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Li Zhijian <lizhijian@fujitsu.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Usama Arif
|
bfe0857c20 |
Revert "mm: skip CMA pages when they are not available"
This reverts commit |
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|
Linus Torvalds
|
7a3fad30fd |
Random number generator updates for Linux 6.11-rc1.
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Jason A. Donenfeld
|
9651fcedf7 |
mm: add MAP_DROPPABLE for designating always lazily freeable mappings
The vDSO getrandom() implementation works with a buffer allocated with a
new system call that has certain requirements:
- It shouldn't be written to core dumps.
* Easy: VM_DONTDUMP.
- It should be zeroed on fork.
* Easy: VM_WIPEONFORK.
- It shouldn't be written to swap.
* Uh-oh: mlock is rlimited.
* Uh-oh: mlock isn't inherited by forks.
- It shouldn't reserve actual memory, but it also shouldn't crash when
page faulting in memory if none is available
* Uh-oh: VM_NORESERVE means segfaults.
It turns out that the vDSO getrandom() function has three really nice
characteristics that we can exploit to solve this problem:
1) Due to being wiped during fork(), the vDSO code is already robust to
having the contents of the pages it reads zeroed out midway through
the function's execution.
2) In the absolute worst case of whatever contingency we're coding for,
we have the option to fallback to the getrandom() syscall, and
everything is fine.
3) The buffers the function uses are only ever useful for a maximum of
60 seconds -- a sort of cache, rather than a long term allocation.
These characteristics mean that we can introduce VM_DROPPABLE, which
has the following semantics:
a) It never is written out to swap.
b) Under memory pressure, mm can just drop the pages (so that they're
zero when read back again).
c) It is inherited by fork.
d) It doesn't count against the mlock budget, since nothing is locked.
e) If there's not enough memory to service a page fault, it's not fatal,
and no signal is sent.
This way, allocations used by vDSO getrandom() can use:
VM_DROPPABLE | VM_DONTDUMP | VM_WIPEONFORK | VM_NORESERVE
And there will be no problem with OOMing, crashing on overcommitment,
using memory when not in use, not wiping on fork(), coredumps, or
writing out to swap.
In order to let vDSO getrandom() use this, expose these via mmap(2) as
MAP_DROPPABLE.
Note that this involves removing the MADV_FREE special case from
sort_folio(), which according to Yu Zhao is unnecessary and will simply
result in an extra call to shrink_folio_list() in the worst case. The
chunk removed reenables the swapbacked flag, which we don't want for
VM_DROPPABLE, and we can't conditionalize it here because there isn't a
vma reference available.
Finally, the provided self test ensures that this is working as desired.
Cc: linux-mm@kvack.org
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
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|
Yu Zhao
|
30d77b7eef |
mm/mglru: fix ineffective protection calculation
mem_cgroup_calculate_protection() is not stateless and should only be used
as part of a top-down tree traversal. shrink_one() traverses the per-node
memcg LRU instead of the root_mem_cgroup tree, and therefore it should not
call mem_cgroup_calculate_protection().
The existing misuse in shrink_one() can cause ineffective protection of
sub-trees that are grandchildren of root_mem_cgroup. Fix it by reusing
lru_gen_age_node(), which already traverses the root_mem_cgroup tree, to
calculate the protection.
Previously lru_gen_age_node() opportunistically skips the first pass,
i.e., when scan_control->priority is DEF_PRIORITY. On the second pass,
lruvec_is_sizable() uses appropriate scan_control->priority, set by
set_initial_priority() from lru_gen_shrink_node(), to decide whether a
memcg is too small to reclaim from.
Now lru_gen_age_node() unconditionally traverses the root_mem_cgroup tree.
So it should call set_initial_priority() upfront, to make sure
lruvec_is_sizable() uses appropriate scan_control->priority on the first
pass. Otherwise, lruvec_is_reclaimable() can return false negatives and
result in premature OOM kills when min_ttl_ms is used.
Link: https://lkml.kernel.org/r/20240712232956.1427127-1-yuzhao@google.com
Fixes:
|
||
|
Yu Zhao
|
3f74e6bd3b |
mm/mglru: fix overshooting shrinker memory
set_initial_priority() tries to jump-start global reclaim by estimating
the priority based on cold/hot LRU pages. The estimation does not account
for shrinker objects, and it cannot do so because their sizes can be in
different units other than page.
If shrinker objects are the majority, e.g., on TrueNAS SCALE 24.04.0 where
ZFS ARC can use almost all system memory, set_initial_priority() can
vastly underestimate how much memory ARC shrinker can evict and assign
extreme low values to scan_control->priority, resulting in overshoots of
shrinker objects.
To reproduce the problem, using TrueNAS SCALE 24.04.0 with 32GB DRAM, a
test ZFS pool and the following commands:
fio --name=mglru.file --numjobs=36 --ioengine=io_uring \
--directory=/root/test-zfs-pool/ --size=1024m --buffered=1 \
--rw=randread --random_distribution=random \
--time_based --runtime=1h &
for ((i = 0; i < 20; i++))
do
sleep 120
fio --name=mglru.anon --numjobs=16 --ioengine=mmap \
--filename=/dev/zero --size=1024m --fadvise_hint=0 \
--rw=randrw --random_distribution=random \
--time_based --runtime=1m
done
To fix the problem:
1. Cap scan_control->priority at or above DEF_PRIORITY/2, to prevent
the jump-start from being overly aggressive.
2. Account for the progress from mm_account_reclaimed_pages(), to
prevent kswapd_shrink_node() from raising the priority
unnecessarily.
Link: https://lkml.kernel.org/r/20240711191957.939105-2-yuzhao@google.com
Fixes:
|
||
|
Yu Zhao
|
8b671fe1a8 |
mm/mglru: fix div-by-zero in vmpressure_calc_level()
evict_folios() uses a second pass to reclaim folios that have gone through
page writeback and become clean before it finishes the first pass, since
folio_rotate_reclaimable() cannot handle those folios due to the
isolation.
The second pass tries to avoid potential double counting by deducting
scan_control->nr_scanned. However, this can result in underflow of
nr_scanned, under a condition where shrink_folio_list() does not increment
nr_scanned, i.e., when folio_trylock() fails.
The underflow can cause the divisor, i.e., scale=scanned+reclaimed in
vmpressure_calc_level(), to become zero, resulting in the following crash:
[exception RIP: vmpressure_work_fn+101]
process_one_work at ffffffffa3313f2b
Since scan_control->nr_scanned has no established semantics, the potential
double counting has minimal risks. Therefore, fix the problem by not
deducting scan_control->nr_scanned in evict_folios().
Link: https://lkml.kernel.org/r/20240711191957.939105-1-yuzhao@google.com
Fixes:
|
||
|
Barry Song
|
e5a119c4a6 |
mm/vmscan: drop checking if _deferred_list is empty before using TTU_SYNC
The optimization of list_empty(&folio->_deferred_list) aimed to prevent
increasing the PTL duration when a large folio is partially unmapped, for
example, from subpage 0 to subpage (nr - 2).
But Ryan's commit
|
||
|
Dan Schatzberg
|
68cd9050d8 |
mm: add swappiness= arg to memory.reclaim
Allow proactive reclaimers to submit an additional swappiness=<val> argument to memory.reclaim. This overrides the global or per-memcg swappiness setting for that reclaim attempt. For example: echo "2M swappiness=0" > /sys/fs/cgroup/memory.reclaim will perform reclaim on the rootcg with a swappiness setting of 0 (no swap) regardless of the vm.swappiness sysctl setting. Userspace proactive reclaimers use the memory.reclaim interface to trigger reclaim. The memory.reclaim interface does not allow for any way to effect the balance of file vs anon during proactive reclaim. The only approach is to adjust the vm.swappiness setting. However, there are a few reasons we look to control the balance of file vs anon during proactive reclaim, separately from reactive reclaim: * Swapout should be limited to manage SSD write endurance. In near-OOM situations we are fine with lots of swap-out to avoid OOMs. As these are typically rare events, they have relatively little impact on write endurance. However, proactive reclaim runs continuously and so its impact on SSD write endurance is more significant. Therefore it is desireable to control swap-out for proactive reclaim separately from reactive reclaim * Some userspace OOM killers like systemd-oomd[1] support OOM killing on swap exhaustion. This makes sense if the swap exhaustion is triggered due to reactive reclaim but less so if it is triggered due to proactive reclaim (e.g. one could see OOMs when free memory is ample but anon is just particularly cold). Therefore, it's desireable to have proactive reclaim reduce or stop swap-out before the threshold at which OOM killing occurs. In the case of Meta's Senpai proactive reclaimer, we adjust vm.swappiness before writes to memory.reclaim[2]. This has been in production for nearly two years and has addressed our needs to control proactive vs reactive reclaim behavior but is still not ideal for a number of reasons: * vm.swappiness is a global setting, adjusting it can race/interfere with other system administration that wishes to control vm.swappiness. In our case, we need to disable Senpai before adjusting vm.swappiness. * vm.swappiness is stateful - so a crash or restart of Senpai can leave a misconfigured setting. This requires some additional management to record the "desired" setting and ensure Senpai always adjusts to it. With this patch, we avoid these downsides of adjusting vm.swappiness globally. [1]https://www.freedesktop.org/software/systemd/man/latest/systemd-oomd.service.html [2]https://github.com/facebookincubator/oomd/blob/main/src/oomd/plugins/Senpai.cpp#L585-L598 Link: https://lkml.kernel.org/r/20240103164841.2800183-3-schatzberg.dan@gmail.com Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Suggested-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Yue Zhao <findns94@gmail.com> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Dan Schatzberg
|
410abb20ac |
mm: add defines for min/max swappiness
Patch series "Add swappiness argument to memory.reclaim", v6. This patch proposes augmenting the memory.reclaim interface with a swappiness=<val> argument that overrides the swappiness value for that instance of proactive reclaim. Userspace proactive reclaimers use the memory.reclaim interface to trigger reclaim. The memory.reclaim interface does not allow for any way to effect the balance of file vs anon during proactive reclaim. The only approach is to adjust the vm.swappiness setting. However, there are a few reasons we look to control the balance of file vs anon during proactive reclaim, separately from reactive reclaim: * Swapout should be limited to manage SSD write endurance. In near-OOM situations we are fine with lots of swap-out to avoid OOMs. As these are typically rare events, they have relatively little impact on write endurance. However, proactive reclaim runs continuously and so its impact on SSD write endurance is more significant. Therefore it is desireable to control swap-out for proactive reclaim separately from reactive reclaim * Some userspace OOM killers like systemd-oomd[1] support OOM killing on swap exhaustion. This makes sense if the swap exhaustion is triggered due to reactive reclaim but less so if it is triggered due to proactive reclaim (e.g. one could see OOMs when free memory is ample but anon is just particularly cold). Therefore, it's desireable to have proactive reclaim reduce or stop swap-out before the threshold at which OOM killing occurs. In the case of Meta's Senpai proactive reclaimer, we adjust vm.swappiness before writes to memory.reclaim[2]. This has been in production for nearly two years and has addressed our needs to control proactive vs reactive reclaim behavior but is still not ideal for a number of reasons: * vm.swappiness is a global setting, adjusting it can race/interfere with other system administration that wishes to control vm.swappiness. In our case, we need to disable Senpai before adjusting vm.swappiness. * vm.swappiness is stateful - so a crash or restart of Senpai can leave a misconfigured setting. This requires some additional management to record the "desired" setting and ensure Senpai always adjusts to it. With this patch, we avoid these downsides of adjusting vm.swappiness globally. Previously, this exact interface addition was proposed by Yosry[3]. In response, Roman proposed instead an interface to specify precise file/anon/slab reclaim amounts[4]. More recently Huan also proposed this as well[5] and others similarly questioned if this was the proper interface. Previous proposals sought to use this to allow proactive reclaimers to effectively perform a custom reclaim algorithm by issuing proactive reclaim with different settings to control file vs anon reclaim (e.g. to only reclaim anon from some applications). Responses argued that adjusting swappiness is a poor interface for custom reclaim. In contrast, I argue in favor of a swappiness setting not as a way to implement custom reclaim algorithms but rather to bias the balance of anon vs file due to differences of proactive vs reactive reclaim. In this context, swappiness is the existing interface for controlling this balance and this patch simply allows for it to be configured differently for proactive vs reactive reclaim. Specifying explicit amounts of anon vs file pages to reclaim feels inappropriate for this prupose. Proactive reclaimers are un-aware of the relative age of file vs anon for a cgroup which makes it difficult to manage proactive reclaim of different memory pools. A proactive reclaimer would need some amount of anon reclaim attempts separate from the amount of file reclaim attempts which seems brittle given that it's difficult to observe the impact. [1]https://www.freedesktop.org/software/systemd/man/latest/systemd-oomd.service.html [2]https://github.com/facebookincubator/oomd/blob/main/src/oomd/plugins/Senpai.cpp#L585-L598 [3]https://lore.kernel.org/linux-mm/CAJD7tkbDpyoODveCsnaqBBMZEkDvshXJmNdbk51yKSNgD7aGdg@mail.gmail.com/ [4]https://lore.kernel.org/linux-mm/YoPHtHXzpK51F%2F1Z@carbon/ [5]https://lore.kernel.org/lkml/20231108065818.19932-1-link@vivo.com/ This patch (of 2): We use the constants 0 and 200 in a few places in the mm code when referring to the min and max swappiness. This patch adds MIN_SWAPPINESS and MAX_SWAPPINESS #defines to improve clarity. There are no functional changes. Link: https://lkml.kernel.org/r/20240103164841.2800183-1-schatzberg.dan@gmail.com Link: https://lkml.kernel.org/r/20240103164841.2800183-2-schatzberg.dan@gmail.com Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Chris Li <chrisl@kernel.org> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yue Zhao <findns94@gmail.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Roman Gushchin
|
87024f5837 |
mm: memcg: rename soft limit reclaim-related functions
Rename exported function related to the softlimit reclaim to have memcg1_ prefix. Link: https://lkml.kernel.org/r/20240625005906.106920-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
593a10dabe |
mm: refactor folio_undo_large_rmappable()
Folios of order <= 1 are not in deferred list, the check of order is added
into folio_undo_large_rmappable() from commit
|
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|
Honggyu Kim
|
8f75267d22 |
mm: rename alloc_demote_folio to alloc_migrate_folio
The alloc_demote_folio can also be used for general migration including both demotion and promotion so it'd be better to rename it from alloc_demote_folio to alloc_migrate_folio. Link: https://lkml.kernel.org/r/20240614030010.751-3-honggyu.kim@sk.com Signed-off-by: Honggyu Kim <honggyu.kim@sk.com> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Gregory Price <gregory.price@memverge.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Hyeongtak Ji <hyeongtak.ji@sk.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Honggyu Kim
|
a00ce85af2 |
mm: make alloc_demote_folio externally invokable for migration
Patch series "DAMON based tiered memory management for CXL memory", v6.
Introduction
============
With the advent of CXL/PCIe attached DRAM, which will be called simply as
CXL memory in this cover letter, some systems are becoming more
heterogeneous having memory systems with different latency and bandwidth
characteristics. They are usually handled as different NUMA nodes in
separate memory tiers and CXL memory is used as slow tiers because of its
protocol overhead compared to local DRAM.
In this kind of systems, we need to be careful placing memory pages on
proper NUMA nodes based on the memory access frequency. Otherwise, some
frequently accessed pages might reside on slow tiers and it makes
performance degradation unexpectedly. Moreover, the memory access
patterns can be changed at runtime.
To handle this problem, we need a way to monitor the memory access
patterns and migrate pages based on their access temperature. The
DAMON(Data Access MONitor) framework and its DAMOS(DAMON-based Operation
Schemes) can be useful features for monitoring and migrating pages. DAMOS
provides multiple actions based on DAMON monitoring results and it can be
used for proactive reclaim, which means swapping cold pages out with
DAMOS_PAGEOUT action, but it doesn't support migration actions such as
demotion and promotion between tiered memory nodes.
This series supports two new DAMOS actions; DAMOS_MIGRATE_HOT for
promotion from slow tiers and DAMOS_MIGRATE_COLD for demotion from fast
tiers. This prevents hot pages from being stuck on slow tiers, which
makes performance degradation and cold pages can be proactively demoted to
slow tiers so that the system can increase the chance to allocate more hot
pages to fast tiers.
The DAMON provides various tuning knobs but we found that the proactive
demotion for cold pages is especially useful when the system is running
out of memory on its fast tier nodes.
Our evaluation result shows that it reduces the performance slowdown
compared to the default memory policy from 11% to 3~5% when the system
runs under high memory pressure on its fast tier DRAM nodes.
DAMON configuration
===================
The specific DAMON configuration doesn't have to be in the scope of this
patch series, but some rough idea is better to be shared to explain the
evaluation result.
The DAMON provides many knobs for fine tuning but its configuration file
is generated by HMSDK[3]. It includes gen_config.py script that generates
a json file with the full config of DAMON knobs and it creates multiple
kdamonds for each NUMA node when the DAMON is enabled so that it can run
hot/cold based migration for tiered memory.
Evaluation Workload
===================
The performance evaluation is done with redis[4], which is a widely used
in-memory database and the memory access patterns are generated via
YCSB[5]. We have measured two different workloads with zipfian and latest
distributions but their configs are slightly modified to make memory usage
higher and execution time longer for better evaluation.
The idea of evaluation using these migrate_{hot,cold} actions covers
system-wide memory management rather than partitioning hot/cold pages of a
single workload. The default memory allocation policy creates pages to
the fast tier DRAM node first, then allocates newly created pages to the
slow tier CXL node when the DRAM node has insufficient free space. Once
the page allocation is done then those pages never move between NUMA
nodes. It's not true when using numa balancing, but it is not the scope
of this DAMON based tiered memory management support.
If the working set of redis can be fit fully into the DRAM node, then the
redis will access the fast DRAM only. Since the performance of DRAM only
is faster than partially accessing CXL memory in slow tiers, this
environment is not useful to evaluate this patch series.
To make pages of redis be distributed across fast DRAM node and slow CXL
node to evaluate our migrate_{hot,cold} actions, we pre-allocate some cold
memory externally using mmap and memset before launching redis-server. We
assumed that there are enough amount of cold memory in datacenters as
TMO[6] and TPP[7] papers mentioned.
The evaluation sequence is as follows.
1. Turn on DAMON with DAMOS_MIGRATE_COLD action for DRAM node and
DAMOS_MIGRATE_HOT action for CXL node. It demotes cold pages on DRAM
node and promotes hot pages on CXL node in a regular interval.
2. Allocate a huge block of cold memory by calling mmap and memset at
the fast tier DRAM node, then make the process sleep to make the fast
tier has insufficient space for redis-server.
3. Launch redis-server and load prebaked snapshot image, dump.rdb. The
redis-server consumes 52GB of anon pages and 33GB of file pages, but
due to the cold memory allocated at 2, it fails allocating the entire
memory of redis-server on the fast tier DRAM node so it partially
allocates the remaining on the slow tier CXL node. The ratio of
DRAM:CXL depends on the size of the pre-allocated cold memory.
4. Run YCSB to make zipfian or latest distribution of memory accesses to
redis-server, then measure its execution time when it's completed.
5. Repeat 4 over 50 times to measure the average execution time for each
run.
6. Increase the cold memory size then repeat goes to 2.
For each test at 4 took about a minute so repeating it 50 times almost
took about 1 hour for each test with a specific cold memory from 440GB to
500GB in 10GB increments for each evaluation. So it took about more than
10 hours for both zipfian and latest workloads to get the entire
evaluation results. Repeating the same test set multiple times doesn't
show much difference so I think it might be enough to make the result
reliable.
Evaluation Results
==================
All the result values are normalized to DRAM-only execution time because
the workload cannot be faster than DRAM-only unless the workload hits the
peak bandwidth but our redis test doesn't go beyond the bandwidth limit.
So the DRAM-only execution time is the ideal result without affected by
the gap between DRAM and CXL performance difference. The NUMA node
environment is as follows.
node0 - local DRAM, 512GB with a CPU socket (fast tier)
node1 - disabled
node2 - CXL DRAM, 96GB, no CPU attached (slow tier)
The following is the result of generating zipfian distribution to
redis-server and the numbers are averaged by 50 times of execution.
1. YCSB zipfian distribution read only workload
memory pressure with cold memory on node0 with 512GB of local DRAM.
====================+================================================+=========
| cold memory occupied by mmap and memset |
| 0G 440G 450G 460G 470G 480G 490G 500G |
====================+================================================+=========
Execution time normalized to DRAM-only values | GEOMEAN
--------------------+------------------------------------------------+---------
DRAM-only | 1.00 - - - - - - - | 1.00
CXL-only | 1.19 - - - - - - - | 1.19
default | - 1.00 1.05 1.08 1.12 1.14 1.18 1.18 | 1.11
DAMON tiered | - 1.03 1.03 1.03 1.03 1.03 1.07 *1.05 | 1.04
DAMON lazy | - 1.04 1.03 1.04 1.05 1.06 1.06 *1.06 | 1.05
====================+================================================+=========
CXL usage of redis-server in GB | AVERAGE
--------------------+------------------------------------------------+---------
DRAM-only | 0.0 - - - - - - - | 0.0
CXL-only | 51.4 - - - - - - - | 51.4
default | - 0.6 10.6 20.5 30.5 40.5 47.6 50.4 | 28.7
DAMON tiered | - 0.6 0.5 0.4 0.7 0.8 7.1 5.6 | 2.2
DAMON lazy | - 0.5 3.0 4.5 5.4 6.4 9.4 9.1 | 5.5
====================+================================================+=========
Each test result is based on the execution environment as follows.
DRAM-only: redis-server uses only local DRAM memory.
CXL-only: redis-server uses only CXL memory.
default: default memory policy(MPOL_DEFAULT).
numa balancing disabled.
DAMON tiered: DAMON enabled with DAMOS_MIGRATE_COLD for DRAM
nodes and DAMOS_MIGRATE_HOT for CXL nodes.
DAMON lazy: same as DAMON tiered, but turn on DAMON just
before making memory access request via YCSB.
The above result shows the "default" execution time goes up as the size of
cold memory is increased from 440G to 500G because the more cold memory
used, the more CXL memory is used for the target redis workload and this
makes the execution time increase.
However, "DAMON tiered" and other DAMON results show less slowdown because
the DAMOS_MIGRATE_COLD action at DRAM node proactively demotes
pre-allocated cold memory to CXL node and this free space at DRAM
increases more chance to allocate hot or warm pages of redis-server to
fast DRAM node. Moreover, DAMOS_MIGRATE_HOT action at CXL node also
promotes hot pages of redis-server to DRAM node actively.
As a result, it makes more memory of redis-server stay in DRAM node
compared to "default" memory policy and this makes the performance
improvement.
Please note that the result numbers of "DAMON tiered" and "DAMON lazy" at
500G are marked with * stars, which means their test results are replaced
with reproduced tests that didn't have OOM issue.
That was needed because sometimes the test processes get OOM when DRAM has
insufficient space. The DAMOS_MIGRATE_HOT doesn't kick reclaim but just
gives up migration when there is not enough space at DRAM side. The
problem happens when there is competition between normal allocation and
migration and the migration is done before normal allocation, then the
completely unrelated normal allocation can trigger reclaim, which incurs
OOM.
Because of this issue, I have also tested more cases with
"demotion_enabled" flag enabled to make such reclaim doesn't trigger OOM,
but just demote reclaimed pages. The following test results show more
tests with "kswapd" marked.
2. YCSB zipfian distribution read only workload (with demotion_enabled true)
memory pressure with cold memory on node0 with 512GB of local DRAM.
====================+================================================+=========
| cold memory occupied by mmap and memset |
| 0G 440G 450G 460G 470G 480G 490G 500G |
====================+================================================+=========
Execution time normalized to DRAM-only values | GEOMEAN
--------------------+------------------------------------------------+---------
DAMON tiered | - 1.03 1.03 1.03 1.03 1.03 1.07 1.05 | 1.04
DAMON lazy | - 1.04 1.03 1.04 1.05 1.06 1.06 1.06 | 1.05
DAMON tiered kswapd | - 1.03 1.03 1.03 1.03 1.02 1.02 1.03 | 1.03
DAMON lazy kswapd | - 1.04 1.04 1.04 1.03 1.05 1.04 1.05 | 1.04
====================+================================================+=========
CXL usage of redis-server in GB | AVERAGE
--------------------+------------------------------------------------+---------
DAMON tiered | - 0.6 0.5 0.4 0.7 0.8 7.1 5.6 | 2.2
DAMON lazy | - 0.5 3.0 4.5 5.4 6.4 9.4 9.1 | 5.5
DAMON tiered kswapd | - 0.0 0.0 0.4 0.5 0.1 0.8 1.0 | 0.4
DAMON lazy kswapd | - 4.2 4.6 5.3 1.7 6.8 8.1 5.8 | 5.2
====================+================================================+=========
Each test result is based on the exeuction environment as follows.
DAMON tiered: same as before
DAMON lazy: same as before
DAMON tiered kswapd: same as DAMON tiered, but turn on
/sys/kernel/mm/numa/demotion_enabled to make
kswapd or direct reclaim does demotion.
DAMON lazy kswapd: same as DAMON lazy, but turn on
/sys/kernel/mm/numa/demotion_enabled to make
kswapd or direct reclaim does demotion.
The "DAMON tiered kswapd" and "DAMON lazy kswapd" didn't trigger OOM at
all unlike other tests because kswapd and direct reclaim from DRAM node
can demote reclaimed pages to CXL node independently from DAMON actions
and their results are slightly better than without having
"demotion_enabled".
In summary, the evaluation results show that DAMON memory management with
DAMOS_MIGRATE_{HOT,COLD} actions reduces the performance slowdown compared
to the "default" memory policy from 11% to 3~5% when the system runs with
high memory pressure on its fast tier DRAM nodes.
Having these DAMOS_MIGRATE_HOT and DAMOS_MIGRATE_COLD actions can make
tiered memory systems run more efficiently under high memory pressures.
This patch (of 7):
The alloc_demote_folio can be used out of vmscan.c so it'd be better to
remove static keyword from it.
Link: https://lkml.kernel.org/r/20240614030010.751-1-honggyu.kim@sk.com
Link: https://lkml.kernel.org/r/20240614030010.751-2-honggyu.kim@sk.com
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Gregory Price <gregory.price@memverge.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Shakeel Butt
|
462966dc7d |
mm: vmscan: reset sc->priority on retry
The commit 6be5e186fd65 ("mm: vmscan: restore incremental cgroup
iteration") added a retry reclaim heuristic to iterate all the cgroups
before returning an unsuccessful reclaim but missed to reset the
sc->priority. Let's fix it.
Link: https://lkml.kernel.org/r/20240529154911.3008025-1-shakeel.butt@linux.dev
Fixes: 6be5e186fd65 ("mm: vmscan: restore incremental cgroup iteration")
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reported-by: syzbot+17416257cb95200cba44@syzkaller.appspotmail.com
Tested-by: syzbot+17416257cb95200cba44@syzkaller.appspotmail.com
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Johannes Weiner
|
b82b530740 |
mm: vmscan: restore incremental cgroup iteration
Currently, reclaim always walks the entire cgroup tree in order to ensure
fairness between groups. While overreclaim is limited in shrink_lruvec(),
many of our systems have a sizable number of active groups, and an even
bigger number of idle cgroups with cache left behind by previous jobs; the
mere act of walking all these cgroups can impose significant latency on
direct reclaimers.
In the past, we've used a save-and-restore iterator that enabled
incremental tree walks over multiple reclaim invocations. This ensured
fairness, while keeping the work of individual reclaimers small.
However, in edge cases with a lot of reclaim concurrency, individual
reclaimers would sometimes not see enough of the cgroup tree to make
forward progress and (prematurely) declare OOM. Consequently we switched
to comprehensive walks in
|
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|
Baolin Wang
|
0d648dd5c8 |
mm: drop the 'anon_' prefix for swap-out mTHP counters
The mTHP swap related counters: 'anon_swpout' and 'anon_swpout_fallback' are confusing with an 'anon_' prefix, since the shmem can swap out non-anonymous pages. So drop the 'anon_' prefix to keep consistent with the old swap counter names. This is needed in 6.10-rcX to avoid having an inconsistent ABI out in the field. Link: https://lkml.kernel.org/r/7a8989c13299920d7589007a30065c3e2c19f0e0.1716431702.git.baolin.wang@linux.alibaba.com Fixes: |
||
|
SeongJae Park
|
c961bddb7d |
mm/vmscan: remove ignore_references argument of reclaim_folio_list()
All reclaim_folio_list() callers are passing 'true' for 'ignore_references' parameter. In other words, the parameter is not really being used. Simplify the code by removing the parameter. Link: https://lkml.kernel.org/r/20240429224451.67081-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
SeongJae Park
|
14f5be2a2d |
mm/vmscan: remove ignore_references argument of reclaim_pages()
All reclaim_pages() callers are setting 'ignore_references' parameter 'true'. In other words, the parameter is not really being used. Remove the argument to make it simple. Link: https://lkml.kernel.org/r/20240429224451.67081-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Barry Song
|
d0f048ac39 |
mm: add per-order mTHP anon_swpout and anon_swpout_fallback counters
This helps to display the fragmentation situation of the swapfile, knowing the proportion of how much we haven't split large folios. So far, we only support non-split swapout for anon memory, with the possibility of expanding to shmem in the future. So, we add the "anon" prefix to the counter names. Link: https://lkml.kernel.org/r/20240412114858.407208-3-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Chris Li <chrisl@kernel.org> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Kairui Song <kasong@tencent.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Ryan Roberts
|
5ed890ce51 |
mm: vmscan: avoid split during shrink_folio_list()
Now that swap supports storing all mTHP sizes, avoid splitting large folios before swap-out. This benefits performance of the swap-out path by eliding split_folio_to_list(), which is expensive, and also sets us up for swapping in large folios in a future series. If the folio is partially mapped, we continue to split it since we want to avoid the extra IO overhead and storage of writing out pages uneccessarily. THP_SWPOUT and THP_SWPOUT_FALLBACK counters should continue to count events only for PMD-mappable folios to avoid user confusion. THP_SWPOUT already has the appropriate guard. Add a guard for THP_SWPOUT_FALLBACK. It may be appropriate to add per-size counters in future. Link: https://lkml.kernel.org/r/20240408183946.2991168-7-ryan.roberts@arm.com Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Barry Song <v-songbaohua@oppo.com> Cc: Barry Song <21cnbao@gmail.com> Cc: Chris Li <chrisl@kernel.org> Cc: Gao Xiang <xiang@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Barry Song
|
73bc32875e |
mm: hold PTL from the first PTE while reclaiming a large folio
Within try_to_unmap_one(), page_vma_mapped_walk() races with other PTE modifications preceded by pte clear. While iterating over PTEs of a large folio, it only starts acquiring PTL from the first valid (present) PTE. PTE modifications can temporarily set PTEs to pte_none. Consequently, the initial PTEs of a large folio might be skipped in try_to_unmap_one(). For example, for an anon folio, if we skip PTE0, we may have PTE0 which is still present, while PTE1 ~ PTE(nr_pages - 1) are swap entries after try_to_unmap_one(). So folio will be still mapped, the folio fails to be reclaimed and is put back to LRU in this round. This also breaks up PTEs optimization such as CONT-PTE on this large folio and may lead to accident folio_split() afterwards. And since a part of PTEs are now swap entries, accessing those parts will introduce overhead - do_swap_page. Although the kernel can withstand all of the above issues, the situation still seems quite awkward and warrants making it more ideal. The same race also occurs with small folios, but they have only one PTE, thus, it won't be possible for them to be partially unmapped. This patch holds PTL from PTE0, allowing us to avoid reading PTE values that are in the process of being transformed. With stable PTE values, we can ensure that this large folio is either completely reclaimed or that all PTEs remain untouched in this round. A corner case is that if we hold PTL from PTE0 and most initial PTEs have been really unmapped before that, we may increase the duration of holding PTL. Thus we only apply this optimization to folios which are still entirely mapped (not in deferred_split list). [akpm@linux-foundation.org: rewrap comment, per Matthew] Link: https://lkml.kernel.org/r/20240306095219.71086-1-21cnbao@gmail.com Signed-off-by: Barry Song <v-songbaohua@oppo.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Chuanhua Han <hanchuanhua@oppo.com> Cc: Gao Xiang <xiang@kernel.org> Cc: Huang, Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Baolin Wang
|
e42dfe4e0a |
mm: record the migration reason for struct migration_target_control
Patch series "make the hugetlb migration strategy consistent", v2. As discussed in previous thread [1], there is an inconsistency when handling hugetlb migration. When handling the migration of freed hugetlb, it prevents fallback to other NUMA nodes in alloc_and_dissolve_hugetlb_folio(). However, when dealing with in-use hugetlb, it allows fallback to other NUMA nodes in alloc_hugetlb_folio_nodemask(), which can break the per-node hugetlb pool and might result in unexpected failures when node bound workloads doesn't get what is asssumed available. This patchset tries to make the hugetlb migration strategy more clear and consistent. Please find details in each patch. [1] https://lore.kernel.org/all/6f26ce22d2fcd523418a085f2c588fe0776d46e7.1706794035.git.baolin.wang@linux.alibaba.com/ This patch (of 2): To support different hugetlb allocation strategies during hugetlb migration based on various migration reasons, record the migration reason in the migration_target_control structure as a preparation. Link: https://lkml.kernel.org/r/cover.1709719720.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/7b95d4981e07211f57139fc5b1f7ce91b920cee4.1709719720.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Andrew Morton
|
5e28061128 | Merge branch 'master' into mm-stable | ||
|
Byungchul Park
|
d221dd5fea |
mm, vmscan: retry kswapd's priority loop with cache_trim_mode off on failure
With cache_trim_mode on, reclaim logic doesn't bother reclaiming anon
pages. However, it should be more careful to use the mode because it's
going to prevent anon pages from being reclaimed even if there are a huge
number of anon pages that are cold and should be reclaimed. Even worse,
that leads kswapd_failures to reach MAX_RECLAIM_RETRIES and stopping
kswapd from functioning until direct reclaim eventually works to resume
kswapd.
So kswapd needs to retry its scan priority loop with cache_trim_mode off
again if the mode doesn't work for reclaim.
The problematic behavior can be reproduced by:
CONFIG_NUMA_BALANCING enabled
sysctl_numa_balancing_mode set to NUMA_BALANCING_MEMORY_TIERING
numa node0 (8GB local memory, 16 CPUs)
numa node1 (8GB slow tier memory, no CPUs)
Sequence:
1) echo 3 > /proc/sys/vm/drop_caches
2) To emulate the system with full of cold memory in local DRAM, run
the following dummy program and never touch the region:
mmap(0, 8 * 1024 * 1024 * 1024, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE | MAP_POPULATE, -1, 0);
3) Run any memory intensive work e.g. XSBench.
4) Check if numa balancing is working e.i. promotion/demotion.
5) Iterate 1) ~ 4) until numa balancing stops.
With this, you could see that promotion/demotion are not working because
kswapd has stopped due to ->kswapd_failures >= MAX_RECLAIM_RETRIES.
Interesting vmstat delta's differences between before and after are like:
+-----------------------+-------------------------------+
| interesting vmstat | before | after |
+-----------------------+-------------------------------+
| nr_inactive_anon | 321935 | 1664772 |
| nr_active_anon | 1780700 | 437834 |
| nr_inactive_file | 30425 | 40882 |
| nr_active_file | 14961 | 3012 |
| pgpromote_success | 356 | 1293122 |
| pgpromote_candidate | 21953245 | 1824148 |
| pgactivate | 1844523 | 3311907 |
| pgdeactivate | 50634 |
|
||
|
Matthew Wilcox (Oracle)
|
47932e7048 |
mm: remove folio from deferred split list before uncharging it
When freeing a large folio, we must remove it from the deferred split list before we uncharge it as each memcg has its own deferred split list (with associated lock) and removing a folio from the deferred split list while holding the wrong lock will corrupt that list and cause various related problems. Link: https://lore.kernel.org/linux-mm/367a14f7-340e-4b29-90ae-bc3fcefdd5f4@arm.com/ Link: https://lkml.kernel.org/r/20240311191835.312162-1-willy@infradead.org Fixes: |
||
|
Matthew Wilcox (Oracle)
|
29f3843026 |
mm: free folios directly in move_folios_to_lru()
The few folios which can't be moved to the LRU list (because their refcount dropped to zero) used to be returned to the caller to dispose of. Make this simpler to call by freeing the folios directly through free_unref_folios(). Link: https://lkml.kernel.org/r/20240227174254.710559-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
bc2ff4cbc3 |
mm: free folios in a batch in shrink_folio_list()
Use free_unref_page_batch() to free the folios. This may increase the number of IPIs from calling try_to_unmap_flush() more often, but that's going to be very workload-dependent. It may even reduce the number of IPIs as we now batch-free large folios instead of freeing them one at a time. Link: https://lkml.kernel.org/r/20240227174254.710559-12-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: David Hildenbrand <david@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Barry Song
|
2864f3d0f5 |
mm: madvise: pageout: ignore references rather than clearing young
While doing MADV_PAGEOUT, the current code will clear PTE young so that
vmscan won't read young flags to allow the reclamation of madvised folios
to go ahead. It seems we can do it by directly ignoring references, thus
we can remove tlb flush in madvise and rmap overhead in vmscan.
Regarding the side effect, in the original code, if a parallel thread runs
side by side to access the madvised memory with the thread doing madvise,
folios will get a chance to be re-activated by vmscan (though the time gap
is actually quite small since checking PTEs is done immediately after
clearing PTEs young). But with this patch, they will still be reclaimed.
But this behaviour doing PAGEOUT and doing access at the same time is
quite silly like DoS. So probably, we don't need to care. Or ignoring
the new access during the quite small time gap is even better.
For DAMON's DAMOS_PAGEOUT based on physical address region, we still keep
its behaviour as is since a physical address might be mapped by multiple
processes. MADV_PAGEOUT based on virtual address is actually much more
aggressive on reclamation. To untouch paddr's DAMOS_PAGEOUT, we simply
pass ignore_references as false in reclaim_pages().
A microbench as below has shown 6% decrement on the latency of
MADV_PAGEOUT,
#define PGSIZE 4096
main()
{
int i;
#define SIZE 512*1024*1024
volatile long *p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
for (i = 0; i < SIZE/sizeof(long); i += PGSIZE / sizeof(long))
p[i] = 0x11;
madvise(p, SIZE, MADV_PAGEOUT);
}
w/o patch w/ patch
root@10:~# time ./a.out root@10:~# time ./a.out
real 0m49.634s real 0m46.334s
user 0m0.637s user 0m0.648s
sys 0m47.434s sys 0m44.265s
Link: https://lkml.kernel.org/r/20240226005739.24350-1-21cnbao@gmail.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Vlastimil Babka
|
803de9000f |
mm, vmscan: prevent infinite loop for costly GFP_NOIO | __GFP_RETRY_MAYFAIL allocations
Sven reports an infinite loop in __alloc_pages_slowpath() for costly order
__GFP_RETRY_MAYFAIL allocations that are also GFP_NOIO. Such combination
can happen in a suspend/resume context where a GFP_KERNEL allocation can
have __GFP_IO masked out via gfp_allowed_mask.
Quoting Sven:
1. try to do a "costly" allocation (order > PAGE_ALLOC_COSTLY_ORDER)
with __GFP_RETRY_MAYFAIL set.
2. page alloc's __alloc_pages_slowpath tries to get a page from the
freelist. This fails because there is nothing free of that costly
order.
3. page alloc tries to reclaim by calling __alloc_pages_direct_reclaim,
which bails out because a zone is ready to be compacted; it pretends
to have made a single page of progress.
4. page alloc tries to compact, but this always bails out early because
__GFP_IO is not set (it's not passed by the snd allocator, and even
if it were, we are suspending so the __GFP_IO flag would be cleared
anyway).
5. page alloc believes reclaim progress was made (because of the
pretense in item 3) and so it checks whether it should retry
compaction. The compaction retry logic thinks it should try again,
because:
a) reclaim is needed because of the early bail-out in item 4
b) a zonelist is suitable for compaction
6. goto 2. indefinite stall.
(end quote)
The immediate root cause is confusing the COMPACT_SKIPPED returned from
__alloc_pages_direct_compact() (step 4) due to lack of __GFP_IO to be
indicating a lack of order-0 pages, and in step 5 evaluating that in
should_compact_retry() as a reason to retry, before incrementing and
limiting the number of retries. There are however other places that
wrongly assume that compaction can happen while we lack __GFP_IO.
To fix this, introduce gfp_compaction_allowed() to abstract the __GFP_IO
evaluation and switch the open-coded test in try_to_compact_pages() to use
it.
Also use the new helper in:
- compaction_ready(), which will make reclaim not bail out in step 3, so
there's at least one attempt to actually reclaim, even if chances are
small for a costly order
- in_reclaim_compaction() which will make should_continue_reclaim()
return false and we don't over-reclaim unnecessarily
- in __alloc_pages_slowpath() to set a local variable can_compact,
which is then used to avoid retrying reclaim/compaction for costly
allocations (step 5) if we can't compact and also to skip the early
compaction attempt that we do in some cases
Link: https://lkml.kernel.org/r/20240221114357.13655-2-vbabka@suse.cz
Fixes:
|
||
|
Kinsey Ho
|
4acef5694e |
mm/mglru: improve swappiness handling
The reclaimable number of anon pages used to set initial reclaim priority is only based on get_swappiness(). Use can_reclaim_anon_pages() to include NUMA node demotion. Also move the swappiness handling of when !__GFP_IO in try_to_shrink_lruvec() into isolate_folios(). Link: https://lkml.kernel.org/r/20240214060538.3524462-6-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
cc25bbe10a |
mm/mglru: improve struct lru_gen_mm_walk
Rename max_seq to seq in struct lru_gen_mm_walk to keep consistent with struct lru_gen_mm_state. Note that seq is not always up to date with max_seq from lru_gen_folio. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-5-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
2d823764fa |
mm/mglru: improve reset_mm_stats()
struct lruvec* is already a field of struct lru_gen_mm_walk. Remove the parameter struct lruvec* into functions that already have access to struct lru_gen_mm_walk*. Also, we do not need to handle reset histogram stats when !should_walk_mmu(). Remove the call to reset_mm_stats() in iterate_mm_list_nowalk(). Link: https://lkml.kernel.org/r/20240214060538.3524462-4-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
51973cc9e5 |
mm/mglru: improve should_run_aging()
scan_control *sc does not need to be passed into should_run_aging(), as it provides only the reclaim priority. This can be moved to get_nr_to_scan(). Refactor should_run_aging() and get_nr_to_scan() to improve code readability. No functional changes. Link: https://lkml.kernel.org/r/20240214060538.3524462-3-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kinsey Ho
|
1ce2292c14 |
mm/mglru: drop unused parameter
Patch series "mm/mglru: code cleanup and refactoring" This provides MGLRU code cleanup and refactoring for better readability. This patch (of 5): struct scan_control *sc is currently passed into try_to_inc_max_seq() and run_aging(). This parameter is not used. Drop the unused parameter struct scan_control *sc. No functional change. Link: https://lkml.kernel.org/r/20240214060538.3524462-1-kinseyho@google.com Link: https://lkml.kernel.org/r/20240214060538.3524462-2-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Donet Tom <donettom@linux.vnet.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hao Ge
|
9814171852 |
mm/vmscan: make too_many_isolated return bool
too_many_isolated() should return bool as does the similar too_many_isolated() in mm/compaction.c. Link: https://lkml.kernel.org/r/20240205042618.108140-1-gehao@kylinos.cn Signed-off-by: Hao Ge <gehao@kylinos.cn> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Hao Ge
|
e321d7c934 |
mm/vmscan: change the type of file from int to bool
Change the type of file from int to bool because is_file_lru return bool Link: https://lkml.kernel.org/r/20240131103802.122920-1-gehao@kylinos.cn Signed-off-by: Hao Ge <gehao@kylinos.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Levi Yun
|
96200c9150 |
kswapd: replace try_to_freeze() with kthread_freezable_should_stop()
Instead of using try_to_freeze, use kthread_freezable_should_stop in kswapd. By this, we can avoid unnecessary freezing when kswapd should stop. Link: https://lkml.kernel.org/r/20240126152556.58791-1-ppbuk5246@gmail.com Signed-off-by: Levi Yun <ppbuk5246@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Linus Torvalds
|
fb46e22a9e |
Many singleton patches against the MM code. The patch series which
are included in this merge do the following:
- Peng Zhang has done some mapletree maintainance work in the
series
"maple_tree: add mt_free_one() and mt_attr() helpers"
"Some cleanups of maple tree"
- In the series "mm: use memmap_on_memory semantics for dax/kmem"
Vishal Verma has altered the interworking between memory-hotplug
and dax/kmem so that newly added 'device memory' can more easily
have its memmap placed within that newly added memory.
- Matthew Wilcox continues folio-related work (including a few
fixes) in the patch series
"Add folio_zero_tail() and folio_fill_tail()"
"Make folio_start_writeback return void"
"Fix fault handler's handling of poisoned tail pages"
"Convert aops->error_remove_page to ->error_remove_folio"
"Finish two folio conversions"
"More swap folio conversions"
- Kefeng Wang has also contributed folio-related work in the series
"mm: cleanup and use more folio in page fault"
- Jim Cromie has improved the kmemleak reporting output in the
series "tweak kmemleak report format".
- In the series "stackdepot: allow evicting stack traces" Andrey
Konovalov to permits clients (in this case KASAN) to cause
eviction of no longer needed stack traces.
- Charan Teja Kalla has fixed some accounting issues in the page
allocator's atomic reserve calculations in the series "mm:
page_alloc: fixes for high atomic reserve caluculations".
- Dmitry Rokosov has added to the samples/ dorectory some sample
code for a userspace memcg event listener application. See the
series "samples: introduce cgroup events listeners".
- Some mapletree maintanance work from Liam Howlett in the series
"maple_tree: iterator state changes".
- Nhat Pham has improved zswap's approach to writeback in the
series "workload-specific and memory pressure-driven zswap
writeback".
- DAMON/DAMOS feature and maintenance work from SeongJae Park in
the series
"mm/damon: let users feed and tame/auto-tune DAMOS"
"selftests/damon: add Python-written DAMON functionality tests"
"mm/damon: misc updates for 6.8"
- Yosry Ahmed has improved memcg's stats flushing in the series
"mm: memcg: subtree stats flushing and thresholds".
- In the series "Multi-size THP for anonymous memory" Ryan Roberts
has added a runtime opt-in feature to transparent hugepages which
improves performance by allocating larger chunks of memory during
anonymous page faults.
- Matthew Wilcox has also contributed some cleanup and maintenance
work against eh buffer_head code int he series "More buffer_head
cleanups".
- Suren Baghdasaryan has done work on Andrea Arcangeli's series
"userfaultfd move option". UFFDIO_MOVE permits userspace heap
compaction algorithms to move userspace's pages around rather than
UFFDIO_COPY'a alloc/copy/free.
- Stefan Roesch has developed a "KSM Advisor", in the series
"mm/ksm: Add ksm advisor". This is a governor which tunes KSM's
scanning aggressiveness in response to userspace's current needs.
- Chengming Zhou has optimized zswap's temporary working memory
use in the series "mm/zswap: dstmem reuse optimizations and
cleanups".
- Matthew Wilcox has performed some maintenance work on the
writeback code, both code and within filesystems. The series is
"Clean up the writeback paths".
- Andrey Konovalov has optimized KASAN's handling of alloc and
free stack traces for secondary-level allocators, in the series
"kasan: save mempool stack traces".
- Andrey also performed some KASAN maintenance work in the series
"kasan: assorted clean-ups".
- David Hildenbrand has gone to town on the rmap code. Cleanups,
more pte batching, folio conversions and more. See the series
"mm/rmap: interface overhaul".
- Kinsey Ho has contributed some maintenance work on the MGLRU
code in the series "mm/mglru: Kconfig cleanup".
- Matthew Wilcox has contributed lruvec page accounting code
cleanups in the series "Remove some lruvec page accounting
functions".
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Merge tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
- Peng Zhang has done some mapletree maintainance work in the series
'maple_tree: add mt_free_one() and mt_attr() helpers'
'Some cleanups of maple tree'
- In the series 'mm: use memmap_on_memory semantics for dax/kmem'
Vishal Verma has altered the interworking between memory-hotplug
and dax/kmem so that newly added 'device memory' can more easily
have its memmap placed within that newly added memory.
- Matthew Wilcox continues folio-related work (including a few fixes)
in the patch series
'Add folio_zero_tail() and folio_fill_tail()'
'Make folio_start_writeback return void'
'Fix fault handler's handling of poisoned tail pages'
'Convert aops->error_remove_page to ->error_remove_folio'
'Finish two folio conversions'
'More swap folio conversions'
- Kefeng Wang has also contributed folio-related work in the series
'mm: cleanup and use more folio in page fault'
- Jim Cromie has improved the kmemleak reporting output in the series
'tweak kmemleak report format'.
- In the series 'stackdepot: allow evicting stack traces' Andrey
Konovalov to permits clients (in this case KASAN) to cause eviction
of no longer needed stack traces.
- Charan Teja Kalla has fixed some accounting issues in the page
allocator's atomic reserve calculations in the series 'mm:
page_alloc: fixes for high atomic reserve caluculations'.
- Dmitry Rokosov has added to the samples/ dorectory some sample code
for a userspace memcg event listener application. See the series
'samples: introduce cgroup events listeners'.
- Some mapletree maintanance work from Liam Howlett in the series
'maple_tree: iterator state changes'.
- Nhat Pham has improved zswap's approach to writeback in the series
'workload-specific and memory pressure-driven zswap writeback'.
- DAMON/DAMOS feature and maintenance work from SeongJae Park in the
series
'mm/damon: let users feed and tame/auto-tune DAMOS'
'selftests/damon: add Python-written DAMON functionality tests'
'mm/damon: misc updates for 6.8'
- Yosry Ahmed has improved memcg's stats flushing in the series 'mm:
memcg: subtree stats flushing and thresholds'.
- In the series 'Multi-size THP for anonymous memory' Ryan Roberts
has added a runtime opt-in feature to transparent hugepages which
improves performance by allocating larger chunks of memory during
anonymous page faults.
- Matthew Wilcox has also contributed some cleanup and maintenance
work against eh buffer_head code int he series 'More buffer_head
cleanups'.
- Suren Baghdasaryan has done work on Andrea Arcangeli's series
'userfaultfd move option'. UFFDIO_MOVE permits userspace heap
compaction algorithms to move userspace's pages around rather than
UFFDIO_COPY'a alloc/copy/free.
- Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm:
Add ksm advisor'. This is a governor which tunes KSM's scanning
aggressiveness in response to userspace's current needs.
- Chengming Zhou has optimized zswap's temporary working memory use
in the series 'mm/zswap: dstmem reuse optimizations and cleanups'.
- Matthew Wilcox has performed some maintenance work on the writeback
code, both code and within filesystems. The series is 'Clean up the
writeback paths'.
- Andrey Konovalov has optimized KASAN's handling of alloc and free
stack traces for secondary-level allocators, in the series 'kasan:
save mempool stack traces'.
- Andrey also performed some KASAN maintenance work in the series
'kasan: assorted clean-ups'.
- David Hildenbrand has gone to town on the rmap code. Cleanups, more
pte batching, folio conversions and more. See the series 'mm/rmap:
interface overhaul'.
- Kinsey Ho has contributed some maintenance work on the MGLRU code
in the series 'mm/mglru: Kconfig cleanup'.
- Matthew Wilcox has contributed lruvec page accounting code cleanups
in the series 'Remove some lruvec page accounting functions'"
* tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits)
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
mm, treewide: introduce NR_PAGE_ORDERS
selftests/mm: add separate UFFDIO_MOVE test for PMD splitting
selftests/mm: skip test if application doesn't has root privileges
selftests/mm: conform test to TAP format output
selftests: mm: hugepage-mmap: conform to TAP format output
selftests/mm: gup_test: conform test to TAP format output
mm/selftests: hugepage-mremap: conform test to TAP format output
mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
mm/memcontrol: remove __mod_lruvec_page_state()
mm/khugepaged: use a folio more in collapse_file()
slub: use a folio in __kmalloc_large_node
slub: use folio APIs in free_large_kmalloc()
slub: use alloc_pages_node() in alloc_slab_page()
mm: remove inc/dec lruvec page state functions
mm: ratelimit stat flush from workingset shrinker
kasan: stop leaking stack trace handles
mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
mm/mglru: add dummy pmd_dirty()
...
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Kirill A. Shutemov
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5e0a760b44 |
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
commit
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Li Zhijian
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b805ab3c69 |
mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
Demotion can work well without CONFIG_NUMA_BALANCING. But the commit |
||
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Kinsey Ho
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7eb2d01a1b |
mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
Improve code readability by removing CONFIG_TRANSPARENT_HUGEPAGE, since the compiler should be able to automatically optimize out the code that promotes THPs during page table walks. No functional changes. Link: https://lkml.kernel.org/r/20231227141205.2200125-6-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kinsey Ho
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745b13e647 |
mm/mglru: remove CONFIG_MEMCG
Remove CONFIG_MEMCG in a refactoring to improve code readability at the cost of a few bytes in struct lru_gen_folio per node when CONFIG_MEMCG=n. Link: https://lkml.kernel.org/r/20231227141205.2200125-4-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kinsey Ho
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61dd3f246b |
mm/mglru: add CONFIG_LRU_GEN_WALKS_MMU
Add CONFIG_LRU_GEN_WALKS_MMU such that if disabled, the code that walks page tables to promote pages into the youngest generation will not be built. Also improves code readability by adding two helper functions get_mm_state() and get_next_mm(). Link: https://lkml.kernel.org/r/20231227141205.2200125-3-kinseyho@google.com Signed-off-by: Kinsey Ho <kinseyho@google.com> Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Tested-by: Donet Tom <donettom@linux.vnet.ibm.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yu Zhao
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c28ac3c7eb |
mm/mglru: skip special VMAs in lru_gen_look_around()
Special VMAs like VM_PFNMAP can contain anon pages from COW. There isn't
much profit in doing lookaround on them. Besides, they can trigger the
pte_special() warning in get_pte_pfn().
Skip them in lru_gen_look_around().
Link: https://lkml.kernel.org/r/20231223045647.1566043-1-yuzhao@google.com
Fixes:
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Yosry Ahmed
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7d7ef0a468 |
mm: memcg: restore subtree stats flushing
Stats flushing for memcg currently follows the following rules: - Always flush the entire memcg hierarchy (i.e. flush the root). - Only one flusher is allowed at a time. If someone else tries to flush concurrently, they skip and return immediately. - A periodic flusher flushes all the stats every 2 seconds. The reason this approach is followed is because all flushes are serialized by a global rstat spinlock. On the memcg side, flushing is invoked from userspace reads as well as in-kernel flushers (e.g. reclaim, refault, etc). This approach aims to avoid serializing all flushers on the global lock, which can cause a significant performance hit under high concurrency. This approach has the following problems: - Occasionally a userspace read of the stats of a non-root cgroup will be too expensive as it has to flush the entire hierarchy [1]. - Sometimes the stats accuracy are compromised if there is an ongoing flush, and we skip and return before the subtree of interest is actually flushed, yielding stale stats (by up to 2s due to periodic flushing). This is more visible when reading stats from userspace, but can also affect in-kernel flushers. The latter problem is particulary a concern when userspace reads stats after an event occurs, but gets stats from before the event. Examples: - When memory usage / pressure spikes, a userspace OOM handler may look at the stats of different memcgs to select a victim based on various heuristics (e.g. how much private memory will be freed by killing this). Reading stale stats from before the usage spike in this case may cause a wrongful OOM kill. - A proactive reclaimer may read the stats after writing to memory.reclaim to measure the success of the reclaim operation. Stale stats from before reclaim may give a false negative. - Reading the stats of a parent and a child memcg may be inconsistent (child larger than parent), if the flush doesn't happen when the parent is read, but happens when the child is read. As for in-kernel flushers, they will occasionally get stale stats. No regressions are currently known from this, but if there are regressions, they would be very difficult to debug and link to the source of the problem. This patch aims to fix these problems by restoring subtree flushing, and removing the unified/coalesced flushing logic that skips flushing if there is an ongoing flush. This change would introduce a significant regression with global stats flushing thresholds. With per-memcg stats flushing thresholds, this seems to perform really well. The thresholds protect the underlying lock from unnecessary contention. This patch was tested in two ways to ensure the latency of flushing is up to par, on a machine with 384 cpus: - A synthetic test with 5000 concurrent workers in 500 cgroups doing allocations and reclaim, as well as 1000 readers for memory.stat (variation of [2]). No regressions were noticed in the total runtime. Note that significant regressions in this test are observed with global stats thresholds, but not with per-memcg thresholds. - A synthetic stress test for concurrently reading memcg stats while memory allocation/freeing workers are running in the background, provided by Wei Xu [3]. With 250k threads reading the stats every 100ms in 50k cgroups, 99.9% of reads take <= 50us. Less than 0.01% of reads take more than 1ms, and no reads take more than 100ms. [1] https://lore.kernel.org/lkml/CABWYdi0c6__rh-K7dcM_pkf9BJdTRtAU08M43KO9ME4-dsgfoQ@mail.gmail.com/ [2] https://lore.kernel.org/lkml/CAJD7tka13M-zVZTyQJYL1iUAYvuQ1fcHbCjcOBZcz6POYTV-4g@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CAAPL-u9D2b=iF5Lf_cRnKxUfkiEe0AMDTu6yhrUAzX0b6a6rDg@mail.gmail.com/ [akpm@linux-foundation.org: fix mm/zswap.c] [yosryahmed@google.com: remove stats flushing mutex] Link: https://lkml.kernel.org/r/CAJD7tkZgP3m-VVPn+fF_YuvXeQYK=tZZjJHj=dzD=CcSSpp2qg@mail.gmail.com Link: https://lkml.kernel.org/r/20231129032154.3710765-6-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Acked-by: Shakeel Butt <shakeelb@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Andrew Morton
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a721aeac8b | sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes | ||
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Yu Zhao
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4376807bf2 |
mm/mglru: reclaim offlined memcgs harder
In the effort to reduce zombie memcgs [1], it was discovered that the
memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically,
instead of rotating them to the tail of the current generation
(MEMCG_LRU_TAIL) for a second attempt, it moves them to the next
generation (MEMCG_LRU_YOUNG) after the first attempt.
Not applying enough pressure on offlined memcgs can cause them to build
up, and this can be particularly harmful to memory-constrained systems.
On Pixel 8 Pro, launching apps for 50 cycles:
Before After Change
Zombie memcgs 45 35 -22%
[1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com
Fixes:
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Yu Zhao
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8aa4206179 |
mm/mglru: respect min_ttl_ms with memcgs
While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru:
try to stop at high watermarks"), it was discovered that the memcg LRU can
breach the thrashing protection imposed by min_ttl_ms.
Before the memcg LRU:
kswapd()
shrink_node_memcgs()
mem_cgroup_iter()
inc_max_seq() // always hit a different memcg
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
After the memcg LRU:
kswapd()
shrink_many()
restart:
iterate the memcg LRU:
inc_max_seq() // occasionally hit the same memcg
if raced with lru_gen_rotate_memcg():
goto restart
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
Specifically, when the restart happens in shrink_many(), it needs to stick
with the (memcg LRU) generation it began with. In other words, it should
neither re-read memcg_lru->seq nor age an lruvec of a different
generation. Otherwise it can hit the same memcg multiple times without
giving lru_gen_age_node() a chance to check the timestamp of that memcg's
oldest generation (against min_ttl_ms).
[1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com
Fixes:
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Yu Zhao
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5095a2b239 |
mm/mglru: try to stop at high watermarks
The initial MGLRU patchset didn't include the memcg LRU support, and it relied on should_abort_scan(), added by commit |
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Yu Zhao
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081488051d |
mm/mglru: fix underprotected page cache
Unmapped folios accessed through file descriptors can be underprotected.
Those folios are added to the oldest generation based on:
1. The fact that they are less costly to reclaim (no need to walk the
rmap and flush the TLB) and have less impact on performance (don't
cause major PFs and can be non-blocking if needed again).
2. The observation that they are likely to be single-use. E.g., for
client use cases like Android, its apps parse configuration files
and store the data in heap (anon); for server use cases like MySQL,
it reads from InnoDB files and holds the cached data for tables in
buffer pools (anon).
However, the oldest generation can be very short lived, and if so, it
doesn't provide the PID controller with enough time to respond to a surge
of refaults. (Note that the PID controller uses weighted refaults and
those from evicted generations only take a half of the whole weight.) In
other words, for a short lived generation, the moving average smooths out
the spike quickly.
To fix the problem:
1. For folios that are already on LRU, if they can be beyond the
tracking range of tiers, i.e., five accesses through file
descriptors, move them to the second oldest generation to give them
more time to age. (Note that tiers are used by the PID controller
to statistically determine whether folios accessed multiple times
through file descriptors are worth protecting.)
2. When adding unmapped folios to LRU, adjust the placement of them so
that they are not too close to the tail. The effect of this is
similar to the above.
On Android, launching 55 apps sequentially:
Before After Change
workingset_refault_anon 25641024 25598972 0%
workingset_refault_file 115016834 106178438 -8%
Link: https://lkml.kernel.org/r/20231208061407.2125867-1-yuzhao@google.com
Fixes:
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Li Zhijian
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23e9f01389 |
mm/vmstat: move pgdemote_* to per-node stats
Demotion will migrate pages across nodes. Previously, only the global demotion statistics were accounted for. Changed them to per-node statistics, making it easier to observe where demotion occurs on each node. This will help to identify which nodes are under pressure. This patch also make pgdemote_* behind CONFIG_NUMA_BALANCING, since demotion is not available for !CONFIG_NUMA_BALANCING With this patch, here is a sample where node0 node1 are DRAM, node3 is PMEM: Global stats: $ grep demote /proc/vmstat pgdemote_kswapd 254288 pgdemote_direct 113497 pgdemote_khugepaged 0 Per-node stats: $ grep demote /sys/devices/system/node/node0/vmstat # demotion source pgdemote_kswapd 68454 pgdemote_direct 83431 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node1/vmstat # demotion source pgdemote_kswapd 185834 pgdemote_direct 30066 pgdemote_khugepaged 0 $ grep demote /sys/devices/system/node/node3/vmstat # demotion target pgdemote_kswapd 0 pgdemote_direct 0 pgdemote_khugepaged 0 Link: https://lkml.kernel.org/r/20231103031450.1456523-1-lizhijian@fujitsu.com Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> Acked-by: "Huang, Ying" <ying.huang@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Jaewon Kim
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8c2214fc9a |
mm: multi-gen LRU: reuse some legacy trace events
As the legacy lru provides, the mglru needs some trace events for debugging. Let's reuse following legacy events for the mglru. trace_mm_vmscan_lru_isolate trace_mm_vmscan_lru_shrink_inactive Here's an example mm_vmscan_lru_isolate: classzone=2 order=0 nr_requested=4096 nr_scanned=64 nr_skipped=0 nr_taken=64 lru=inactive_file mm_vmscan_lru_shrink_inactive: nid=0 nr_scanned=64 nr_reclaimed=63 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=1 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC Link: https://lkml.kernel.org/r/20231003114155.21869-1-jaewon31.kim@samsung.com Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: SeongJae Park <sj@kernel.org> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: T.J. Mercier <tjmercier@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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liwenyu
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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> |
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Vlastimil Babka
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3dfbb555c9 |
mm, vmscan: remove ISOLATE_UNMAPPED
This isolate_mode_t flag is effectively unused since
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Xin Hao
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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> |
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liujinlong
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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> |
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Qi Zheng
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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> |
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Angus Chen
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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> |
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Vern Hao
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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> |
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David Hildenbrand
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3d2c908768 |
mm/swap: inline folio_set_swap_entry() and folio_swap_entry()
Let's simply work on the folio directly and remove the helpers. Link: https://lkml.kernel.org/r/20230821160849.531668-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Chris Li <chrisl@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Andrew Morton
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5994eabf3b | merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes | ||
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Charan Teja Kalla
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b7108d6631 |
Multi-gen LRU: skip CMA pages when they are not eligible
This patch is based on the commit 5da226dbfce3("mm: skip CMA pages when
they are not available") which skips cma pages reclaim when they are not
eligible for the current allocation context. In mglru, such pages are
added to the tail of the immediate generation to maintain better LRU
order, which is unlike the case of conventional LRU where such pages are
directly added to the head of the LRU list(akin to adding to head of the
youngest generation in mglru).
No observable issue without this patch on MGLRU, but logically it make
sense to skip the CMA page reclaim when those pages can't be satisfied for
the current allocation context.
Link: https://lkml.kernel.org/r/1691568344-13475-1-git-send-email-quic_charante@quicinc.com
Fixes:
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Kalesh Singh
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a3235ea2a8 |
Multi-gen LRU: fix can_swap in lru_gen_look_around()
walk->can_swap might be invalid since it's not guaranteed to be
initialized for the particular lruvec. Instead deduce it from the folio
type (anon/file).
Link: https://lkml.kernel.org/r/20230802025606.346758-3-kaleshsingh@google.com
Fixes:
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Kalesh Singh
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bb5e7f234e |
Multi-gen LRU: avoid race in inc_min_seq()
inc_max_seq() will try to inc_min_seq() if nr_gens == MAX_NR_GENS. This
is because the generations are reused (the last oldest now empty
generation will become the next youngest generation).
inc_min_seq() is retried until successful, dropping the lru_lock
and yielding the CPU on each failure, and retaking the lock before
trying again:
while (!inc_min_seq(lruvec, type, can_swap)) {
spin_unlock_irq(&lruvec->lru_lock);
cond_resched();
spin_lock_irq(&lruvec->lru_lock);
}
However, the initial condition that required incrementing the min_seq
(nr_gens == MAX_NR_GENS) is not retested. This can change by another
call to inc_max_seq() from run_aging() with force_scan=true from the
debugfs interface.
Since the eviction stalls when the nr_gens == MIN_NR_GENS, avoid
unnecessarily incrementing the min_seq by rechecking the number of
generations before each attempt.
This issue was uncovered in previous discussion on the list by Yu Zhao
and Aneesh Kumar [1].
[1] https://lore.kernel.org/linux-mm/CAOUHufbO7CaVm=xjEb1avDhHVvnC8pJmGyKcFf2iY_dpf+zR3w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230802025606.346758-2-kaleshsingh@google.com
Fixes:
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Kalesh Singh
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669281ee7e |
Multi-gen LRU: fix per-zone reclaim
MGLRU has a LRU list for each zone for each type (anon/file) in each
generation:
long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
The min_seq (oldest generation) can progress independently for each
type but the max_seq (youngest generation) is shared for both anon and
file. This is to maintain a common frame of reference.
In order for eviction to advance the min_seq of a type, all the per-zone
lists in the oldest generation of that type must be empty.
The eviction logic only considers pages from eligible zones for
eviction or promotion.
scan_folios() {
...
for (zone = sc->reclaim_idx; zone >= 0; zone--) {
...
sort_folio(); // Promote
...
isolate_folio(); // Evict
}
...
}
Consider the system has the movable zone configured and default 4
generations. The current state of the system is as shown below
(only illustrating one type for simplicity):
Type: ANON
Zone DMA32 Normal Movable Device
Gen 0 0 0 4GB 0
Gen 1 0 1GB 1MB 0
Gen 2 1MB 4GB 1MB 0
Gen 3 1MB 1MB 1MB 0
Now consider there is a GFP_KERNEL allocation request (eligible zone
index <= Normal), evict_folios() will return without doing any work
since there are no pages to scan in the eligible zones of the oldest
generation. Reclaim won't make progress until triggered from a ZONE_MOVABLE
allocation request; which may not happen soon if there is a lot of free
memory in the movable zone. This can lead to OOM kills, although there
is 1GB pages in the Normal zone of Gen 1 that we have not yet tried to
reclaim.
This issue is not seen in the conventional active/inactive LRU since
there are no per-zone lists.
If there are no (not enough) folios to scan in the eligible zones, move
folios from ineligible zone (zone_index > reclaim_index) to the next
generation. This allows for the progression of min_seq and reclaiming
from the next generation (Gen 1).
Qualcomm, Mediatek and raspberrypi [1] discovered this issue independently.
[1] https://github.com/raspberrypi/linux/issues/5395
Link: https://lkml.kernel.org/r/20230802025606.346758-1-kaleshsingh@google.com
Fixes:
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T.J. Mercier
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6867c7a332 |
mm: multi-gen LRU: don't spin during memcg release
When a memcg is in the process of being released mem_cgroup_tryget will
fail because its reference count has already reached 0. This can happen
during reclaim if the memcg has already been offlined, and we reclaim all
remaining pages attributed to the offlined memcg. shrink_many attempts to
skip the empty memcg in this case, and continue reclaiming from the
remaining memcgs in the old generation. If there is only one memcg
remaining, or if all remaining memcgs are in the process of being released
then shrink_many will spin until all memcgs have finished being released.
The release occurs through a workqueue, so it can take a while before
kswapd is able to make any further progress.
This fix results in reductions in kswapd activity and direct reclaim in
a test where 28 apps (working set size > total memory) are repeatedly
launched in a random sequence:
A B delta ratio(%)
allocstall_movable 5962 3539 -2423 -40.64
allocstall_normal 2661 2417 -244 -9.17
kswapd_high_wmark_hit_quickly 53152 7594 -45558 -85.71
pageoutrun 57365 11750 -45615 -79.52
Link: https://lkml.kernel.org/r/20230814151636.1639123-1-tjmercier@google.com
Fixes:
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Suren Baghdasaryan
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49b0638502 |
mm: enable page walking API to lock vmas during the walk
walk_page_range() and friends often operate under write-locked mmap_lock. With introduction of vma locks, the vmas have to be locked as well during such walks to prevent concurrent page faults in these areas. Add an additional member to mm_walk_ops to indicate locking requirements for the walk. The change ensures that page walks which prevent concurrent page faults by write-locking mmap_lock, operate correctly after introduction of per-vma locks. With per-vma locks page faults can be handled under vma lock without taking mmap_lock at all, so write locking mmap_lock would not stop them. The change ensures vmas are properly locked during such walks. A sample issue this solves is do_mbind() performing queue_pages_range() to queue pages for migration. Without this change a concurrent page can be faulted into the area and be left out of migration. Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Suggested-by: Jann Horn <jannh@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Peter Xu <peterx@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Howells
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0201ebf274 |
mm: merge folio_has_private()/filemap_release_folio() call pairs
Patch series "mm, netfs, fscache: Stop read optimisation when folio removed from pagecache", v7. This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. This patch (of 2): Make filemap_release_folio() check folio_has_private(). Then, in most cases, where a call to folio_has_private() is immediately followed by a call to filemap_release_folio(), we can get rid of the test in the pair. There are a couple of sites in mm/vscan.c that this can't so easily be done. In shrink_folio_list(), there are actually three cases (something different is done for incompletely invalidated buffers), but filemap_release_folio() elides two of them. In shrink_active_list(), we don't have have the folio lock yet, so the check allows us to avoid locking the page unnecessarily. A wrapper function to check if a folio needs release is provided for those places that still need to do it in the mm/ directory. This will acquire additional parts to the condition in a future patch. After this, the only remaining caller of folio_has_private() outside of mm/ is a check in fuse. Link: https://lkml.kernel.org/r/20230628104852.3391651-1-dhowells@redhat.com Link: https://lkml.kernel.org/r/20230628104852.3391651-2-dhowells@redhat.com Reported-by: Rohith Surabattula <rohiths.msft@gmail.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steve French <sfrench@samba.org> Cc: Shyam Prasad N <nspmangalore@gmail.com> Cc: Rohith Surabattula <rohiths.msft@gmail.com> Cc: Dave Wysochanski <dwysocha@redhat.com> Cc: Dominique Martinet <asmadeus@codewreck.org> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Xiubo Li <xiubli@redhat.com> Cc: Jingbo Xu <jefflexu@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yosry Ahmed
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1bc545bff4 |
mm/vmscan: fix root proactive reclaim unthrottling unbalanced node
When memory.reclaim was introduced, it became the first case where cgroup_reclaim() is true for the root cgroup. Johannes concluded [1] that for most cases this is okay, except for one case. Historically, kswapd would throttle reclaim on a node if a lot of pages marked for reclaim are under writeback (aka the node is congested). This occurred by setting LRUVEC_CONGESTED bit in lruvec->flags. The bit would be cleared when the node is balanced. Similarly, cgroup reclaim would set the same bit when an lruvec is congested, and clear it on the way out of reclaim (to throttle local reclaimers). Before the introduction of memory.reclaim, the root memcg was the only target of kswapd reclaim, and non-root memcgs were the only targets of cgroup reclaim, so they would never interfere. Using the same bit for both was fine. After memory.reclaim, it is possible for cgroup reclaim on the root cgroup to clear the bit set by kswapd. This would result in reclaim on the node to be unthrottled before the node is balanced. Fix this by introducing separate bits for cgroup-level and node-level congestion. kswapd can unthrottle an lruvec that is marked as congested by cgroup reclaim (as the entire node should no longer be congested), but not vice versa (to prevent premature unthrottling before the entire node is balanced). [1]https://lore.kernel.org/lkml/20230405200150.GA35884@cmpxchg.org/ Link: https://lkml.kernel.org/r/20230621023101.432780-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Closes: https://lore.kernel.org/lkml/20230405200150.GA35884@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> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yosry Ahmed
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7a704474b3 |
mm: memcg: rename and document global_reclaim()
Evidently, global_reclaim() can be a confusing name. Especially that it
used to exist before with a subtly different definition (removed by commit
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