BACKPORT: sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets

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.

Bug: 238390134
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>
(cherry picked from commit 6c24849f
https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git

 cgroup/for-6.5)
[Trivial conflicts in cpuset.c and dealdine.c. Reject new code/fields
that are in upstream but not in 5.15]
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: I8b991e2b25d66adf73a91c656c1a22cc9dbeea7b