On Mon, Sep 04, 2017 at 10:32:37AM -0700, Shakeel Butt wrote:
> On Mon, Sep 4, 2017 at 7:21 AM, Roman Gushchin <guro@xxxxxx> wrote:
> > Introducing of cgroup-aware OOM killer changes the victim selection
> > algorithm used by default: instead of picking the largest process,
> > it will pick the largest memcg and then the largest process inside.
> >
> > This affects only cgroup v2 users.
> >
> > To provide a way to use cgroups v2 if the old OOM victim selection
> > algorithm is preferred for some reason, the nogroupoom mount option
> > is added.
>
> Is this mount option or boot parameter? From the code, it seems like a
> boot parameter.
Sure, you're right.
Fixed version below.
Thank you!
--
>From 0b4757ec8d339fa883e17d4e25a92f45bf5565e0 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <guro@xxxxxx>
Date: Mon, 4 Sep 2017 12:08:52 +0100
Subject: [v7 5/5] mm, oom: allow disabling cgroup-aware OOM killer
Introducing of cgroup-aware OOM killer changes the victim selection
algorithm used by default: instead of picking the largest process,
it will pick the largest memcg and then the largest process inside.
This affects only cgroup v2 users.
To provide a way to use cgroups v2 if the old OOM victim selection
algorithm is preferred for some reason, the cgroup.memory=nogroupoom
boot option is added.
If set, the OOM selection is performed in a "traditional" per-process
way. Both oom_priority and oom_group memcg knobs are ignored.
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: kernel-team@xxxxxx
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
---
Documentation/admin-guide/kernel-parameters.txt | 1 +
mm/memcontrol.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 28f1a0f84456..07891f1030aa 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -489,6 +489,7 @@
Format: <string>
nosocket -- Disable socket memory accounting.
nokmem -- Disable kernel memory accounting.
+ nogroupoom -- Disable cgroup-aware OOM killer.
checkreqprot [SELINUX] Set initial checkreqprot flag value.
Format: { "0" | "1" }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d7dd293897ca..6a8235dc41f6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -87,6 +87,9 @@ static bool cgroup_memory_nosocket;
/* Kernel memory accounting disabled? */
static bool cgroup_memory_nokmem;
+/* Cgroup-aware OOM disabled? */
+static bool cgroup_memory_nogroupoom;
+
/* Whether the swap controller is active */
#ifdef CONFIG_MEMCG_SWAP
int do_swap_account __read_mostly;
@@ -2822,6 +2825,9 @@ bool mem_cgroup_select_oom_victim(struct oom_control *oc)
if (mem_cgroup_disabled())
return false;
+ if (cgroup_memory_nogroupoom)
+ return false;
+
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return false;
@@ -6188,6 +6194,8 @@ static int __init cgroup_memory(char *s)
cgroup_memory_nosocket = true;
if (!strcmp(token, "nokmem"))
cgroup_memory_nokmem = true;
+ if (!strcmp(token, "nogroupoom"))
+ cgroup_memory_nogroupoom = true;
}
return 0;
}
--
2.13.5
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