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Commit 5ac05ce5 authored by Juri Lelli's avatar Juri Lelli Committed by Greg Kroah-Hartman
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sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets



commit 6c24849f 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: default avatarQais Yousef (Google) <qyousef@layalina.io>
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/


Signed-off-by: default avatarJuri Lelli <juri.lelli@redhat.com>
Reviewed-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
[ Fix conflicts in kernel/cgroup/cpuset.c and kernel/sched/deadline.c
  due to pulling new fields and functions. Remove new code and match the
  patch diff. ]
Signed-off-by: default avatarQais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b950133d
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