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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-09 03:52:54 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-09 03:52:54 +0200
commit9cd6357f100b3eb0f5027b1ff1a5eebb9f785145 (patch)
treea09d8c6a7f52edae589990f27ef07071bfa92e9a /Documentation
parentMerge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm6... (diff)
parentcgroup: Documentation: Clarify usage of memory limits (diff)
downloadlinux-9cd6357f100b3eb0f5027b1ff1a5eebb9f785145.tar.xz
linux-9cd6357f100b3eb0f5027b1ff1a5eebb9f785145.zip
Merge tag 'cgroup-for-6.4-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo: - Fix css_set reference leaks on fork failures - Fix CPU hotplug locking in cgroup_transfer_tasks() which is used by cgroup1 cpuset - Doc update * tag 'cgroup-for-6.4-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Documentation: Clarify usage of memory limits cgroup: always put cset in cgroup_css_set_put_fork cgroup: fix missing cpus_read_{lock,unlock}() in cgroup_transfer_tasks()
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst22
1 files changed, 10 insertions, 12 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index f67c0829350b..e592a9364473 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1213,23 +1213,25 @@ PAGE_SIZE multiple when read back.
A read-write single value file which exists on non-root
cgroups. The default is "max".
- Memory usage throttle limit. This is the main mechanism to
- control memory usage of a cgroup. If a cgroup's usage goes
+ Memory usage throttle limit. If a cgroup's usage goes
over the high boundary, the processes of the cgroup are
throttled and put under heavy reclaim pressure.
Going over the high limit never invokes the OOM killer and
- under extreme conditions the limit may be breached.
+ under extreme conditions the limit may be breached. The high
+ limit should be used in scenarios where an external process
+ monitors the limited cgroup to alleviate heavy reclaim
+ pressure.
memory.max
A read-write single value file which exists on non-root
cgroups. The default is "max".
- Memory usage hard limit. This is the final protection
- mechanism. If a cgroup's memory usage reaches this limit and
- can't be reduced, the OOM killer is invoked in the cgroup.
- Under certain circumstances, the usage may go over the limit
- temporarily.
+ Memory usage hard limit. This is the main mechanism to limit
+ memory usage of a cgroup. If a cgroup's memory usage reaches
+ this limit and can't be reduced, the OOM killer is invoked in
+ the cgroup. Under certain circumstances, the usage may go
+ over the limit temporarily.
In default configuration regular 0-order allocations always
succeed unless OOM killer chooses current task as a victim.
@@ -1238,10 +1240,6 @@ PAGE_SIZE multiple when read back.
Caller could retry them differently, return into userspace
as -ENOMEM or silently ignore in cases like disk readahead.
- This is the ultimate protection mechanism. As long as the
- high limit is used and monitored properly, this limit's
- utility is limited to providing the final safety net.
-
memory.reclaim
A write-only nested-keyed file which exists for all cgroups.