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sched: More generic WAKE_AFFINE vs select_idle_sibling()

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Instead of only considering SD_WAKE_AFFINE | SD_PREFER_SIBLING
domains also allow all SD_PREFER_SIBLING domains below a
SD_WAKE_AFFINE domain to change the affinity target.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091112145610.909723612@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-11-12 15:55:29 +01:00 • committed by Ingo Molnar
parent a50bde5130
commit fe3bcfe1f6
1 changed files with 16 additions and 17 deletions
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33
kernel/sched_fair.c
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@ -1333,20 +1333,16 @@ select_idle_sibling(struct task_struct *p, struct sched_domain *sd, int target)
* test in select_task_rq_fair) and the prev_cpu is idle then that's * test in select_task_rq_fair) and the prev_cpu is idle then that's
* always a better target than the current cpu. * always a better target than the current cpu.
*/ */
if (target == cpu) { if (target == cpu && !cpu_rq(prev_cpu)->cfs.nr_running)
if (!cpu_rq(prev_cpu)->cfs.nr_running) return prev_cpu;
target = prev_cpu;
}
/* /*
* Otherwise, iterate the domain and find an elegible idle cpu. * Otherwise, iterate the domain and find an elegible idle cpu.
*/ */
if (target == -1 || target == cpu) { for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) {
for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { if (!cpu_rq(i)->cfs.nr_running) {
if (!cpu_rq(i)->cfs.nr_running) { target = i;
target = i; break;
break;
}
} }
} }
@ -1407,7 +1403,12 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
want_sd = 0; want_sd = 0;
} }
if (want_affine && (tmp->flags & SD_WAKE_AFFINE)) { /*
* While iterating the domains looking for a spanning
* WAKE_AFFINE domain, adjust the affine target to any idle cpu
* in cache sharing domains along the way.
*/
if (want_affine) {
int target = -1; int target = -1;
/* /*
@ -1420,17 +1421,15 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
/* /*
* If there's an idle sibling in this domain, make that * If there's an idle sibling in this domain, make that
* the wake_affine target instead of the current cpu. * the wake_affine target instead of the current cpu.
*
* XXX: should we possibly do this outside of
* WAKE_AFFINE, in case the shared cache domain is
* smaller than the WAKE_AFFINE domain?
*/ */
if (tmp->flags & SD_PREFER_SIBLING) if (tmp->flags & SD_PREFER_SIBLING)
target = select_idle_sibling(p, tmp, target); target = select_idle_sibling(p, tmp, target);
if (target >= 0) { if (target >= 0) {
affine_sd = tmp; if (tmp->flags & SD_WAKE_AFFINE) {
want_affine = 0; affine_sd = tmp;
want_affine = 0;
}
cpu = target; cpu = target;
} }
} }