From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f199.google.com (mail-yw0-f199.google.com [209.85.161.199]) by kanga.kvack.org (Postfix) with ESMTP id E110D6B04B8 for ; Mon, 4 Sep 2017 10:22:02 -0400 (EDT) Received: by mail-yw0-f199.google.com with SMTP id w138so843315yww.2 for ; Mon, 04 Sep 2017 07:22:02 -0700 (PDT) Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com. [67.231.145.42]) by mx.google.com with ESMTPS id o185si1762754ybg.236.2017.09.04.07.22.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Sep 2017 07:22:01 -0700 (PDT) From: Roman Gushchin Subject: [v7 4/5] mm, oom, docs: describe the cgroup-aware OOM killer Date: Mon, 4 Sep 2017 15:21:07 +0100 Message-ID: <20170904142108.7165-5-guro@fb.com> In-Reply-To: <20170904142108.7165-1-guro@fb.com> References: <20170904142108.7165-1-guro@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Roman Gushchin , Michal Hocko , Vladimir Davydov , Johannes Weiner , Tetsuo Handa , Andrew Morton , David Rientjes , Tejun Heo , kernel-team@fb.com, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Update cgroups v2 docs. Signed-off-by: Roman Gushchin Cc: Michal Hocko Cc: Vladimir Davydov Cc: Johannes Weiner Cc: Tetsuo Handa Cc: Andrew Morton 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 | 56 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index a86f3cb88125..5d21bd2e7d55 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. OOM Killer 5-3. IO 5-3-1. IO Interface Files 5-3-2. Writeback @@ -799,6 +800,33 @@ 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.oom_priority + + A read-write single value file which exists on non-root + cgroups. The default is "0". + + An integer number, which defines the order in which + the OOM killer selects victim memory cgroups. + + OOM killer prefers memory cgroups with larger priority if they + are populated with eligible tasks. + + The oom_priority value is compared within sibling cgroups. + + The root cgroup has the oom_priority 0, which cannot be changed. + memory.events A read-only flat-keyed file which exists on non-root cgroups. @@ -1028,6 +1056,34 @@ POSIX_FADV_DONTNEED to relinquish the ownership of memory areas belonging to the affected files to ensure correct memory ownership. +5-2-4. 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 oom_priority. If sibling cgroups have the same priority, +the OOM killer selects one which is the largest memory consumer. + +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. + +Tasks in the root cgroup are treated as independent memory consumers, +and are compared with other memory consumers (memory cgroups and +other tasks in root cgroup). +The root cgroup doesn't support the oom_group 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. + +If there are no cgroups with the enabled memory controller, +the OOM killer is using the "traditional" process-based approach. + + 5-3. IO The "io" controller regulates the distribution of IO resources. This -- 2.13.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org