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Michal Hocko aa187507ef mm: throttle show_mem() from warn_alloc()
Tetsuo has been stressing OOM killer path with many parallel allocation
requests when he has noticed that it is not all that hard to swamp
kernel logs with warn_alloc messages caused by allocation stalls.  Even
though the allocation stall message is triggered only once in 10s there
might be many different tasks hitting it roughly around the same time.

A big part of the output is show_mem() which can generate a lot of
output even on a small machines.  There is no reason to show the state
of memory counter for each allocation stall, especially when multiple of
them are reported in a short time period.  Chances are that not much has
changed since the last report.  This patch simply rate limits show_mem
called from warn_alloc to only dump something once per second.  This
should be enough to give us a clue why an allocation might be stalling
while burst of warnings will not swamp log with too much data.

While we are at it, extract all the show_mem related handling (filters)
into a separate function warn_alloc_show_mem.  This will make the code
cleaner and as a bonus point we can distinguish which part of warn_alloc
got throttled due to rate limiting as ___ratelimit dumps the caller.

[akpm@linux-foundation.org: reduce scope of the ratelimit_states]
Link: http://lkml.kernel.org/r/20161215101510.9030-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-22 16:41:27 -08:00
arch parisc: use generic current.h 2017-02-22 16:41:27 -08:00
block block: use for_each_thread() in sys_ioprio_set()/sys_ioprio_get() 2017-02-22 16:41:27 -08:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto crypto: algif_aead - Fix kernel panic on list_del 2017-02-03 17:45:48 +08:00
Documentation slub: make sysfs directories for memcg sub-caches optional 2017-02-22 16:41:27 -08:00
drivers mm, dax: change pmd_fault() to take only vmf parameter 2017-02-22 16:41:26 -08:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs 9p: fix a potential acl leak 2017-02-22 16:41:27 -08:00
include slab: use memcg_kmem_cache_wq for slab destruction operations 2017-02-22 16:41:27 -08:00
init slub: make sysfs directories for memcg sub-caches optional 2017-02-22 16:41:27 -08:00
ipc ipc/sem.c: fix incorrect sem_lock pairing 2017-01-10 18:31:55 -08:00
kernel kernel/watchdog.c: do not hardcode CPU 0 as the initial thread 2017-02-22 16:41:27 -08:00
lib dma-debug: add comment for failed to check map error 2017-02-22 16:41:26 -08:00
mm mm: throttle show_mem() from warn_alloc() 2017-02-22 16:41:27 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-02-22 10:15:09 -08:00
scripts scripts/tags.sh: include arch/Kconfig* for tags generation 2017-02-22 16:41:26 -08:00
security driver core patches for 4.11-rc1 2017-02-22 11:44:32 -08:00
sound ALSA: hda - adding a new NV HDMI/DP codec ID in the driver 2017-02-09 08:57:47 +01:00
tools tools/vm: add missing Makefile rules 2017-02-22 16:41:26 -08:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM updates for 4.10-rc4 2017-01-17 15:04:59 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add codeaurora.org names for nameless email commits 2017-01-10 18:31:55 -08:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS dax: update MAINTAINERS entries for FS DAX 2017-02-22 16:41:26 -08:00
Makefile Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-02-20 12:21:13 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.