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Roman Gushchin bee07b33db mm: memcontrol: flush percpu slab vmstats on kmem offlining
I've noticed that the "slab" value in memory.stat is sometimes 0, even
if some children memory cgroups have a non-zero "slab" value.  The
following investigation showed that this is the result of the kmem_cache
reparenting in combination with the per-cpu batching of slab vmstats.

At the offlining some vmstat value may leave in the percpu cache, not
being propagated upwards by the cgroup hierarchy.  It means that stats
on ancestor levels are lower than actual.  Later when slab pages are
released, the precise number of pages is substracted on the parent
level, making the value negative.  We don't show negative values, 0 is
printed instead.

To fix this issue, let's flush percpu slab memcg and lruvec stats on
memcg offlining.  This guarantees that numbers on all ancestor levels
are accurate and match the actual number of outstanding slab pages.

Link: http://lkml.kernel.org/r/20190819202338.363363-3-guro@fb.com
Fixes: fb2f2b0adb ("mm: memcg/slab: reparent memcg kmem_caches on cgroup removal")
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-08-30 18:00:50 -07:00
arch ARM: SoC fixes 2019-08-30 10:53:12 -07:00
block block: remove REQ_NOWAIT_INLINE 2019-08-15 11:09:16 -06:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
Documentation ARC updates for 5.3-rc7 2019-08-27 10:50:27 -07:00
drivers ARM: SoC fixes 2019-08-30 10:53:12 -07:00
fs a few small SMB3 fixes, and a larger one to fix various older string handling functions 2019-08-29 17:51:23 -07:00
include mm: memcontrol: flush percpu slab vmstats on kmem offlining 2019-08-30 18:00:50 -07:00
init Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
ipc Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-19 10:42:02 -07:00
kernel arm64 fixes for -rc7 2019-08-28 10:37:21 -07:00
lib Hisilicon fixes for v5.3-rc 2019-08-29 17:23:52 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: memcontrol: flush percpu slab vmstats on kmem offlining 2019-08-30 18:00:50 -07:00
net A fix for a -rc1 regression in rbd and a trivial static checker fix. 2019-08-30 09:09:54 -07:00
samples auxdisplay: Fix a typo in cfag12864b-example.c 2019-08-08 20:00:18 +02:00
scripts SPDX fixes for 5.3-rc5 2019-08-18 09:26:16 -07:00
security keys: ensure that ->match_free() is called in request_key_and_link() 2019-08-30 11:10:55 -07:00
sound sound fixes for 5.3-rc7 2019-08-27 10:42:03 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-08-27 10:12:48 -07:00
usr kbuild: enable arch/s390/include/uapi/asm/zcrypt.h for uapi header test 2019-07-23 10:45:46 +02:00
virt arm64 fixes for -rc7 2019-08-28 10:37:21 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: Add compilation database file 2019-07-27 12:18:19 +09:00
.mailmap A single patch to change my MAINTAINERS address 2019-08-29 17:29:09 +02:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Remove references to dead website. 2019-07-19 12:22:04 -07:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS ARM: SoC fixes 2019-08-30 10:53:12 -07:00
Makefile Linux 5.3-rc6 2019-08-25 12:01:23 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

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.