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Roman Gushchin d648bcc7fe mm: kmem: make memcg_kmem_enabled() irreversible
Historically the kernel memory accounting was an opt-in feature, which
could be enabled for individual cgroups.  But now it's not true, and it's
on by default both on cgroup v1 and cgroup v2.  And as long as a user has
at least one non-root memory cgroup, the kernel memory accounting is on.
So in most setups it's either always on (if memory cgroups are in use and
kmem accounting is not disabled), either always off (otherwise).

memcg_kmem_enabled() is used in many places to guard the kernel memory
accounting code.  If memcg_kmem_enabled() can reverse from returning true
to returning false (as now), we can't rely on it on release paths and have
to check if it was on before.

If we'll make memcg_kmem_enabled() irreversible (always returning true
after returning it for the first time), it'll make the general logic more
simple and robust.  It also will allow to guard some checks which
otherwise would stay unguarded.

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200702180926.1330769-1-guro@fb.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-07 11:33:24 -07:00
arch mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
block for-5.9/block-merge-20200804 2020-08-05 11:12:34 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
Documentation tmpfs: support 64-bit inums per-sb 2020-08-07 11:33:24 -07:00
drivers mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
fs tmpfs: support 64-bit inums per-sb 2020-08-07 11:33:24 -07:00
include tmpfs: support 64-bit inums per-sb 2020-08-07 11:33:24 -07:00
init mm/slab: expand CONFIG_SLAB_FREELIST_HARDENED to include SLAB 2020-08-07 11:33:22 -07:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel kthread: remove incorrect comment in kthread_create_on_cpu() 2020-08-07 11:33:21 -07:00
lib mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm: kmem: make memcg_kmem_enabled() irreversible 2020-08-07 11:33:24 -07:00
net mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -07:00
scripts mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
security mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
sound sound updates for 5.9 2020-08-06 14:27:31 -07:00
tools tools/testing/selftests/cgroup/cgroup_util.c: cg_read_strcmp: fix null pointer dereference 2020-08-07 11:33:21 -07:00
usr usr: Add support for zstd compressed initramfs 2020-07-31 11:49:08 +02:00
virt s390: implement diag318 2020-08-06 12:59:31 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS TTY/Serial patches for 5.9-rc1 2020-08-06 14:56:11 -07:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-08-05 20:13:21 -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.