From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Gushchin Subject: [RFC PATCH v2 7/7] mm,oom,docs: describe the cgroup-aware OOM killer Date: Thu, 1 Jun 2017 19:35:15 +0100 Message-ID: <1496342115-3974-8-git-send-email-guro@fb.com> References: <1496342115-3974-1-git-send-email-guro@fb.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=Cjd+gSEngRMC1gKdJQ6WlCLz1LLzrRa0nqZ0sozGMPQ=; b=iPGpq/fRJTTSDqEXteVM5FcmnZJANmIrhVyxNSx8SVDis7hi37Y/0HTeOqN1Z8RgvX5l EA2zMQU6FiEp8gjQZNCBojuYjVkHRjt56dw2XUyjtEczxpzretLBeqPaPFrN0gujP4hJ nlOtS0UOmnjM4Eje2INg5wnx/pX5fBBwn1U= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector1-fb-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=Cjd+gSEngRMC1gKdJQ6WlCLz1LLzrRa0nqZ0sozGMPQ=; b=JX6Up4Wp5nn/xAGqTw9p23uoQld3aW0CubIgsrsY3VBa7adWpvfBcq4ReXH3/vNBWjiAJJwOafozKOhZ4fSmLUKDiMP7KupcvAxiP0csaEZQOiDIiSHgEu5Je/7L3IuigO7OttyXK7+M+/KYHHD5R7gkuJ/ycHfiCaKV738H3cA= In-Reply-To: <1496342115-3974-1-git-send-email-guro@fb.com> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-mm@kvack.org Cc: Roman Gushchin , Tejun Heo , Johannes Weiner , Li Zefan , Michal Hocko , Vladimir Davydov , Tetsuo Handa , 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: Tejun Heo Cc: Johannes Weiner Cc: Li Zefan Cc: Michal Hocko Cc: Vladimir Davydov Cc: Tetsuo Handa 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 | 47 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 45 insertions(+), 2 deletions(-) diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index dc5e2dc..bb1e45c 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. @@ -831,8 +852,7 @@ PAGE_SIZE multiple when read back. oom The number of times the OOM killer has been invoked in - the cgroup. This may not exactly match the number of - processes killed but should generally be close. + the cgroup. memory.stat @@ -988,6 +1008,29 @@ 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 -- 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