From: Roman Gushchin <guro@fb.com>
To: <linux-mm@vger.kernel.org>
Cc: Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@suse.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>, Tejun Heo <tj@kernel.org>,
<kernel-team@fb.com>, <cgroups@vger.kernel.org>,
<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-mm@kvack.org>
Subject: [PATCH v13 6/7] mm, oom, docs: describe the cgroup-aware OOM killer
Date: Thu, 30 Nov 2017 15:28:23 +0000 [thread overview]
Message-ID: <20171130152824.1591-7-guro@fb.com> (raw)
In-Reply-To: <20171130152824.1591-1-guro@fb.com>
Document the cgroup-aware OOM killer.
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Cc: cgroups@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
---
Documentation/cgroup-v2.txt | 58 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 779211fbb69f..c80a147f94b7 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
@@ -1026,6 +1027,28 @@ 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 consider the memory cgroup as an
+ indivisible memory consumers and compare it with other memory
+ consumers by it's memory footprint.
+ If such memory cgroup is selected as an OOM victim, all
+ processes belonging to it or it's descendants will be killed.
+
+ This applies to system-wide OOM conditions and reaching
+ the hard memory limit of the cgroup and their ancestor.
+ If OOM condition happens in a descendant cgroup with it's own
+ memory limit, the memory cgroup can't be considered
+ as an OOM victim, and OOM killer will not kill all belonging
+ tasks.
+
+ Also, 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
@@ -1229,6 +1252,41 @@ 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, looking for a memory cgroup with the largest
+memory footprint, considering leaf cgroups and cgroups with the
+memory.oom_group option set, which are considered to be an indivisible
+memory consumers.
+
+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 memory.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 other leaf memory cgroups and cgroups with oom_group option set.
+
+If there are no cgroups with the enabled memory controller,
+the OOM killer is using the "traditional" process-based approach.
+
+Please, note that memory charges are not migrating if tasks
+are moved between different memory cgroups. Moving tasks with
+significant memory footprint may affect OOM victim selection logic.
+If it's a case, please, consider creating a common ancestor for
+the source and destination memory cgroups and enabling oom_group
+on ancestor layer.
+
IO
--
--
2.14.3
next prev parent reply other threads:[~2017-11-30 15:31 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-30 15:28 [PATCH v13 0/7] cgroup-aware OOM killer Roman Gushchin
2017-11-30 15:28 ` [PATCH v13 1/7] mm, oom: refactor the oom_kill_process() function Roman Gushchin
2017-11-30 15:28 ` [PATCH v13 2/7] mm: implement mem_cgroup_scan_tasks() for the root memory cgroup Roman Gushchin
2017-11-30 15:28 ` [PATCH v13 3/7] mm, oom: cgroup-aware OOM killer Roman Gushchin
2017-12-01 8:35 ` Michal Hocko
2017-12-07 1:24 ` Andrew Morton
2017-12-07 13:39 ` Roman Gushchin
2017-11-30 15:28 ` [PATCH v13 4/7] mm, oom: introduce memory.oom_group Roman Gushchin
2017-11-30 15:28 ` [PATCH v13 5/7] mm, oom: add cgroup v2 mount option for cgroup-aware OOM killer Roman Gushchin
2017-12-01 8:41 ` Michal Hocko
2017-12-01 13:15 ` Roman Gushchin
2017-12-01 13:31 ` Michal Hocko
2017-12-01 17:00 ` Roman Gushchin
2017-11-30 15:28 ` Roman Gushchin [this message]
2017-12-01 8:41 ` [PATCH v13 6/7] mm, oom, docs: describe the " Michal Hocko
2017-12-01 17:01 ` Roman Gushchin
2017-12-01 17:13 ` Michal Hocko
2017-11-30 15:28 ` [PATCH v13 7/7] cgroup: list groupoom in cgroup features Roman Gushchin
2017-11-30 20:39 ` [PATCH v13 0/7] cgroup-aware OOM killer Andrew Morton
2018-01-10 0:57 ` David Rientjes
2018-01-10 13:11 ` Roman Gushchin
2018-01-10 19:33 ` Andrew Morton
2018-01-11 9:08 ` Michal Hocko
2018-01-11 13:18 ` Roman Gushchin
2018-01-12 22:03 ` David Rientjes
2018-01-15 11:54 ` Michal Hocko
2018-01-16 21:36 ` David Rientjes
2018-01-16 22:09 ` Michal Hocko
2018-01-11 21:57 ` David Rientjes
2018-01-13 17:14 ` Johannes Weiner
2018-01-14 23:44 ` David Rientjes
2018-01-15 16:25 ` Johannes Weiner
2018-01-16 21:21 ` David Rientjes
2018-01-10 20:50 ` David Rientjes
2017-12-01 9:14 ` [PATCH] mm, oom: simplify alloc_pages_before_oomkill handling Michal Hocko
2017-12-01 13:26 ` Tetsuo Handa
2017-12-01 13:32 ` Roman Gushchin
2017-12-01 13:54 ` Michal Hocko
2018-06-05 11:47 ` [PATCH v13 0/7] cgroup-aware OOM killer Michal Hocko
2018-06-05 12:13 ` Michal Hocko
2018-07-13 21:59 ` David Rientjes
2018-07-14 1:55 ` Tetsuo Handa
2018-07-16 21:13 ` Tetsuo Handa
2018-07-16 22:09 ` Roman Gushchin
2018-07-17 0:55 ` Tetsuo Handa
2018-07-31 14:14 ` Tetsuo Handa
2018-08-01 16:37 ` Roman Gushchin
2018-08-01 22:01 ` Tetsuo Handa
2018-08-01 22:55 ` Roman Gushchin
2018-07-16 9:36 ` Michal Hocko
2018-07-17 3:59 ` David Rientjes
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