Commit c372e817 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

cpuset: avoid unnecessary sched domains rebuilding 



When changing 'sched_relax_domain_level', don't rebuild sched domains if
'cpus' is empty or 'sched_load_balance' is not set.

Also make the comments of rebuild_sched_domains() more readable.

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f9b4fb8d

kernel/cpuset.c

+12 −6
Original line number Diff line number Diff line
@@ -496,11 +496,16 @@ update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c) 
/*

 * rebuild_sched_domains()

 *

 * If the flag 'sched_load_balance' of any cpuset with non-empty

 * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset

 * which has that flag enabled, or if any cpuset with a non-empty

 * 'cpus' is removed, then call this routine to rebuild the

 * scheduler's dynamic sched domains.

 * This routine will be called to rebuild the scheduler's dynamic

 * sched domains:

 * - if the flag 'sched_load_balance' of any cpuset with non-empty

 *   'cpus' changes,

 * - or if the 'cpus' allowed changes in any cpuset which has that

 *   flag enabled,

 * - or if the 'sched_relax_domain_level' of any cpuset which has

 *   that flag enabled and with non-empty 'cpus' changes,

 * - or if any cpuset with non-empty 'cpus' is removed,

 * - or if a cpu gets offlined.

 *

 * This routine builds a partial partition of the systems CPUs

 * (the set of non-overlappping cpumask_t's in the array 'part'
@@ -1076,6 +1081,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val) 


	if (val != cs->relax_domain_level) {

		cs->relax_domain_level = val;

		if (!cpus_empty(cs->cpus_allowed) && is_sched_load_balance(cs))

			rebuild_sched_domains();

	}

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