diff options
| author | Konstantin Khlebnikov <khlebnikov@yandex-team.ru> | 2020-06-07 21:42:55 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-08 11:05:58 -0700 |
| commit | db33ec371be8e45956e8cebb5b0fe641f008430b (patch) | |
| tree | 82aa1e1d0e9dfaacfd04d41ad5215c4bf58dd3f3 /Documentation | |
| parent | 490741ab1beb9c9f6580e30c7cd91b17a7560369 (diff) | |
doc: cgroup: update note about conditions when oom killer is invoked
Starting from v4.19 commit 29ef680ae7c2 ("memcg, oom: move out_of_memory
back to the charge path") cgroup oom killer is no longer invoked only
from page faults. Now it implements the same semantics as global OOM
killer: allocation context invokes OOM killer and keeps retrying until
success.
[akpm@linux-foundation.org: fixes per Randy]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: http://lkml.kernel.org/r/158894738928.208854.5244393925922074518.stgit@buzz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index c2a4b652bd1a..ce3e05e41724 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1170,6 +1170,13 @@ PAGE_SIZE multiple when read back. 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. + + Some kinds of allocations don't invoke the OOM killer. + 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. @@ -1226,17 +1233,9 @@ PAGE_SIZE multiple when read back. The number of time the cgroup's memory usage was reached the limit and allocation was about to fail. - Depending on context result could be invocation of OOM - killer and retrying allocation or failing allocation. - - Failed allocation in its turn could be returned into - userspace as -ENOMEM or silently ignored in cases like - disk readahead. For now OOM in memory cgroup kills - tasks iff shortage has happened inside page fault. - This event is not raised if the OOM killer is not considered as an option, e.g. for failed high-order - allocations. + allocations or if caller asked to not retry attempts. oom_kill The number of processes belonging to this cgroup |