After reverting the transition to the generic min heap library, bcache no
longer depends on MIN_HEAP. The select entry can be removed to reduce
code size and shrink the kernel's attack surface.
This change effectively reverts the bcache-related part of commit
92a8b224b8 ("lib/min_heap: introduce non-inline versions of min heap API
functions").
This is part of a series of changes to address a performance regression
caused by the use of the generic min_heap implementation.
As reported by Robert, bcache now suffers from latency spikes, with P100
(max) latency increasing from 600 ms to 2.4 seconds every 5 minutes.
These regressions degrade bcache's effectiveness as a low-latency cache
layer and lead to frequent timeouts and application stalls in production
environments.
Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p1m+KQ@mail.gmail.com
Link: https://lkml.kernel.org/r/20250614202353.1632957-4-visitorckw@gmail.com
Fixes: 866898efbb ("bcache: remove heap-related macros and switch to generic min_heap")
Fixes: 92a8b224b8 ("lib/min_heap: introduce non-inline versions of min heap API functions")
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Reported-by: Robert Pang <robertpang@google.com>
Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ryuPpXQA-JG5XXw@mail.gmail.com
Acked-by: Coly Li <colyli@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Enhance min heap API with non-inline functions and
optimizations", v2.
Add non-inline versions of the min heap API functions in lib/min_heap.c
and updates all users outside of kernel/events/core.c to use these
non-inline versions. To mitigate the performance impact of indirect
function calls caused by the non-inline versions of the swap and compare
functions, a builtin swap has been introduced that swaps elements based on
their size. Additionally, it micro-optimizes the efficiency of the min
heap by pre-scaling the counter, following the same approach as in
lib/sort.c. Documentation for the min heap API has also been added to the
core-api section.
This patch (of 10):
All current min heap API functions are marked with '__always_inline'.
However, as the number of users increases, inlining these functions
everywhere leads to a increase in kernel size.
In performance-critical paths, such as when perf events are enabled and
min heap functions are called on every context switch, it is important to
retain the inline versions for optimal performance. To balance this, the
original inline functions are kept, and additional non-inline versions of
the functions have been added in lib/min_heap.c.
Link: https://lkml.kernel.org/r/20241020040200.939973-1-visitorckw@gmail.com
Link: https://lore.kernel.org/20240522161048.8d8bbc7b153b4ecd92c50666@linux-foundation.org
Link: https://lkml.kernel.org/r/20241020040200.939973-2-visitorckw@gmail.com
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw>
Cc: Coly Li <colyli@suse.de>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Sakai <msakai@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Prep work for bcachefs - being a fork of bcache it also uses closures
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
The "Asynchronous device registration (EXPERIMENTAL)" Kconfig option is
for 2+ years, it is used when registration takes too much time for
massive amount of cached data, to avoid udev task timeout during boot
time.
Many users and products enable this Kconfig option for quite long time
(e.g. SUSE Linux) and it works as expected and no issue reported.
It is time to remove the "EXPERIMENTAL" tag from this Kconfig item.
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20220719042724.8498-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Move the block holder code into a separate file as it is not in any way
related to the other block_dev.c code, and add a new selectable config
option for it so that we don't have to build it without any remapped
drivers selected.
The Kconfig symbol contains a _DEPRECATED suffix to match the comments
added in commit 49731baa41
("block: restore multiple bd_link_disk_holder() support").
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20210804094147.459763-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In order to avoid the experimental async registration interface to
be treated as new kernel ABI for common users, this patch makes it
as an experimental kernel configure BCACHE_ASYNC_REGISTRAION.
This interface is for extreme large cached data situation, to make sure
the bcache device can always created without the udev timeout issue. For
normal users the async or sync registration does not make difference.
In future when we decide to use the asynchronous registration as default
behavior, this experimental interface may be removed.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block
Pull more block updates from Jens Axboe:
- Set of bcache fixes and changes (Coly)
- The flush warn fix (me)
- Small series of BFQ fixes (Paolo)
- wbt hang fix (Ming)
- blktrace fix (Steven)
- blk-mq hardware queue count update fix (Jianchao)
- Various little fixes
* tag 'for-4.19/post-20180822' of git://git.kernel.dk/linux-block: (31 commits)
block/DAC960.c: make some arrays static const, shrinks object size
blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter
blk-mq: init hctx sched after update ctx and hctx mapping
block: remove duplicate initialization
tracing/blktrace: Fix to allow setting same value
pktcdvd: fix setting of 'ret' error return for a few cases
block: change return type to bool
block, bfq: return nbytes and not zero from struct cftype .write() method
block, bfq: improve code of bfq_bfqq_charge_time
block, bfq: reduce write overcharge
block, bfq: always update the budget of an entity when needed
block, bfq: readd missing reset of parent-entity service
blk-wbt: fix IO hang in wbt_wait()
block: don't warn for flush on read-only device
bcache: add the missing comments for smp_mb()/smp_wmb()
bcache: remove unnecessary space before ioctl function pointer arguments
bcache: add missing SPDX header
bcache: move open brace at end of function definitions to next line
bcache: add static const prefix to char * array declarations
bcache: fix code comments style
...
Now we have crc64 calculation in lib/crc64.c, it is unnecessary for
bcache to use its own version. This patch changes bcache code to use
crc64 routines in lib/crc64.c.
Link: http://lkml.kernel.org/r/20180718165545.1622-3-colyli@suse.de
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Michael Lyle <mlyle@lyle.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Noah Massey <noah.massey@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current bcache Kconfig uses '---help---' as header of help information,
for now 'help' is prefered. This patch fixes this style by replacing
'---help---' by 'help' in bcache Kconfig file.
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Shenghui Wang <shhuiw@foxmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As we move stuff around, some doc references are broken. Fix some of
them via this script:
./scripts/documentation-file-ref-check --fix
Manually checked if the produced result is valid, removing a few
false-positives.
Acked-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Coly Li <colyli@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Couple changes:
* Consolidate bch_check_keys() and bch_check_key_order(), and move the
checks that only check_key_order() could do to bch_btree_iter_next().
* Get rid of CONFIG_BCACHE_EDEBUG - now, all that code is compiled in
when CONFIG_BCACHE_DEBUG is enabled, and there's now a sysfs file to
flip on the EDEBUG checks at runtime.
* Dropped an old not terribly useful check in rw_unlock(), and
refactored/improved a some of the other debug code.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
The Kconfig entry for BCACHE selects CLOSURES. But there's no Kconfig
symbol CLOSURES. That symbol was used in development versions of bcache,
but was removed when the closures code was no longer provided as a
kernel library. It can safely be dropped.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Does writethrough and writeback caching, handles unclean shutdown, and
has a bunch of other nifty features motivated by real world usage.
See the wiki at http://bcache.evilpiepirate.org for more.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
