sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets

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commit 6c24849f55 upstream.

Qais reported that iterating over all tasks when rebuilding root domains
for finding out which ones are DEADLINE and need their bandwidth
correctly restored on such root domains can be a costly operation (10+
ms delays on suspend-resume).

To fix the problem keep track of the number of DEADLINE tasks belonging
to each cpuset and then use this information (followup patch) to only
perform the above iteration if DEADLINE tasks are actually present in
the cpuset for which a corresponding root domain is being rebuilt.

Reported-by: Qais Yousef (Google) <qyousef@layalina.io>
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Juri Lelli 2023-08-21 23:19:53 +01:00 • committed by Greg Kroah-Hartman

parent 00f3719c85

commit 74fac5bb0d

4 changed files with 47 additions and 0 deletions

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4

include/linux/cpuset.h

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4

kernel/cgroup/cgroup.c

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25

kernel/cgroup/cpuset.c

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14

kernel/sched/deadline.c

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