Commit 742e8cd3 authored Oct 30, 2019 by Honglei Wang Committed by Tejun Heo Nov 07, 2019

cgroup: freezer: don't change task and cgroups status unnecessarily



It's not necessary to adjust the task state and revisit the state
of source and destination cgroups if the cgroups are not in freeze
state and the task itself is not frozen.

And in this scenario, it wakes up the task who's not supposed to be
ready to run.

Don't do the unnecessary task state adjustment can help stop waking
up the task without a reason.

Signed-off-by: Honglei Wang <honglei.wang@oracle.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 1bb5ec2e

kernel/cgroup/freezer.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -230,6 +230,15 @@ void cgroup_freezer_migrate_task(struct task_struct *task,
		if (task->flags & PF_KTHREAD)
		return;

		/*
		* It's not necessary to do changes if both of the src and dst cgroups
		* are not freezing and task is not frozen.
		*/
		if (!test_bit(CGRP_FREEZE, &src->flags) &&
		!test_bit(CGRP_FREEZE, &dst->flags) &&
		!task->frozen)
		return;

		/*
		* Adjust counters of freezing and frozen tasks.
		* Note, that if the task is frozen, but the destination cgroup is not

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