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: Li 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Li Zefan 2008-07-25 01:47:23 -07:00 committed by Linus Torvalds
parent f9b4fb8dab
commit c372e817af

View File

@ -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'
@ -1076,7 +1081,8 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
if (val != cs->relax_domain_level) {
cs->relax_domain_level = val;
rebuild_sched_domains();
if (!cpus_empty(cs->cpus_allowed) && is_sched_load_balance(cs))
rebuild_sched_domains();
}
return 0;