Document the cgroup-aware OOM killer. Signed-off-by: Roman Gushchin <g...@fb.com> Cc: Michal Hocko <mho...@kernel.org> Cc: Vladimir Davydov <vdavydov....@gmail.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp> Cc: Andrew Morton <a...@linux-foundation.org> Cc: David Rientjes <rient...@google.com> Cc: Tejun Heo <t...@kernel.org> Cc: kernel-t...@fb.com Cc: cgro...@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-ker...@vger.kernel.org Cc: linux...@kvack.org --- Documentation/cgroup-v2.txt | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+)
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index dc44785dc0fa..61a2e959e07a 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -48,6 +48,7 @@ v1 is available under Documentation/cgroup-v1/. 5-2-1. Memory Interface Files 5-2-2. Usage Guidelines 5-2-3. Memory Ownership + 5-2-4. OOM Killer 5-3. IO 5-3-1. IO Interface Files 5-3-2. Writeback @@ -1034,6 +1035,18 @@ PAGE_SIZE multiple when read back. high limit is used and monitored properly, this limit's utility is limited to providing the final safety net. + memory.oom_group + + A read-write single value file which exists on non-root + cgroups. The default is "0". + + If set, OOM killer will kill all processes attached to the cgroup + if selected as an OOM victim. + + OOM killer respects the /proc/pid/oom_score_adj value -1000, + and will never kill the unkillable task, even if memory.oom_group + is set. + memory.events A read-only flat-keyed file which exists on non-root cgroups. The following entries are defined. Unless specified @@ -1237,6 +1250,32 @@ to be accessed repeatedly by other cgroups, it may make sense to use POSIX_FADV_DONTNEED to relinquish the ownership of memory areas belonging to the affected files to ensure correct memory ownership. +OOM Killer +~~~~~~~~~~ + +Cgroup v2 memory controller implements a cgroup-aware OOM killer. +It means that it treats cgroups as first class OOM entities. + +Under OOM conditions the memory controller tries to make the best +choice of a victim, hierarchically looking for a cgroup with the +largest memory footprint. + +By default, OOM killer will kill the biggest task in the selected +memory cgroup. A user can change this behavior by enabling +the per-cgroup oom_group option. If set, it causes the OOM killer +to kill all processes attached to the cgroup, except processes +with oom_score_adj set to -1000. + +This affects both system- and cgroup-wide OOMs. For a cgroup-wide OOM +the memory controller considers only cgroups belonging to the sub-tree +of the OOM'ing cgroup. + +The root cgroup is treated as a leaf memory cgroup, so it's compared +with top-level memory cgroups. + +If there are no cgroups with the enabled memory controller, +the OOM killer is using the "traditional" process-based approach. + IO -- -- 2.13.5 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html