From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752399AbdFUVUM (ORCPT ); Wed, 21 Jun 2017 17:20:12 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:56675 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752143AbdFUVUG (ORCPT ); Wed, 21 Jun 2017 17:20:06 -0400 Authentication-Results: kvack.org; dkim=none (message not signed) header.d=none;kvack.org; dmarc=none action=none header.from=fb.com; From: Roman Gushchin To: CC: Roman Gushchin , Michal Hocko , Vladimir Davydov , Johannes Weiner , Tetsuo Handa , David Rientjes , Tejun Heo , , , , Subject: [v3 6/6] mm,oom,docs: describe the cgroup-aware OOM killer Date: Wed, 21 Jun 2017 22:19:16 +0100 Message-ID: <1498079956-24467-7-git-send-email-guro@fb.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1498079956-24467-1-git-send-email-guro@fb.com> References: <1498079956-24467-1-git-send-email-guro@fb.com> 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Signed-off-by: Roman Gushchin Cc: Michal Hocko Cc: Vladimir Davydov Cc: Johannes Weiner Cc: Tetsuo Handa Cc: David Rientjes Cc: Tejun Heo 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 | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index a86f3cb..7a1a1ac 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -44,6 +44,7 @@ CONTENTS 5-2-1. Memory Interface Files 5-2-2. Usage Guidelines 5-2-3. Memory Ownership + 5-2-4. Cgroup-aware OOM Killer 5-3. IO 5-3-1. IO Interface Files 5-3-2. Writeback @@ -799,6 +800,26 @@ 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_kill_all_tasks + + A read-write single value file which exits on non-root + cgroups. The default is "0". + + Defines whether the OOM killer should treat the cgroup + as a single entity during the victim selection. + + If set, it will cause the OOM killer to kill all belonging + tasks, both in case of a system-wide or cgroup-wide OOM. + + memory.oom_score_adj + + A read-write single value file which exits on non-root + cgroups. The default is "0". + + OOM killer score adjustment, which has as similar meaning + to a per-process value, available via /proc//oom_score_adj. + Should be in a range [-1000, 1000]. + memory.events A read-only flat-keyed file which exists on non-root cgroups. @@ -1028,6 +1049,29 @@ POSIX_FADV_DONTNEED to relinquish the ownership of memory areas belonging to the affected files to ensure correct memory ownership. +5-2-4. Cgroup-aware OOM Killer + +Cgroup v2 memory controller implements a cgroup-aware OOM killer. +It means that it treats memory cgroups as first class OOM entities. + +Under OOM conditions the memory controller tries to make the best +choise of a victim, hierarchically looking for the largest memory +consumer. By default, it will look for the biggest task in the +biggest leaf cgroup. + +But a user can change this behavior by enabling the per-cgroup +oom_kill_all_tasks option. If set, it causes the OOM killer treat +the whole cgroup as an indivisible memory consumer. In case if it's +selected as on OOM victim, all belonging tasks will be killed. + +Tasks in the root cgroup are treated as independent memory consumers, +and are compared with other memory consumers (e.g. leaf cgroups). +The root cgroup doesn't support the oom_kill_all_tasks feature. + +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. + 5-3. IO The "io" controller regulates the distribution of IO resources. This -- 2.7.4