sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets

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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 <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>

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This commit is contained in:

Juri Lelli 2023-05-08 09:58:51 +02:00 • committed by Tejun Heo

parent 111cd11bbc

commit 6c24849f55

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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