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| author | Mike Galbraith <efault@gmx.de> | 2010-03-11 17:17:16 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-09-20 13:18:11 -0700 |
| commit | ac8f51da79873b84461e77ee2b19d02a253add3e (patch) | |
| tree | a9ecad6238a478526f8db5223dfa4ae3f9caf25a /kernel/sched_fair.c | |
| parent | b971284b4af79650f4d7f4caae21c824be3dd7fb (diff) | |
| download | lwn-ac8f51da79873b84461e77ee2b19d02a253add3e.tar.gz lwn-ac8f51da79873b84461e77ee2b19d02a253add3e.zip | |
sched: Fix select_idle_sibling()
commit 8b911acdf08477c059d1c36c21113ab1696c612b upstream
Don't bother with selection when the current cpu is idle. Recent load
balancing changes also make it no longer necessary to check wake_affine()
success before returning the selected sibling, so we now always use it.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268301369.6785.36.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f719dfabf78e..76d9dc0d6ba0 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1432,7 +1432,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ int cpu = smp_processor_id(); int prev_cpu = task_cpu(p); int new_cpu = cpu; - int want_affine = 0; + int want_affine = 0, cpu_idle = !current->pid; int want_sd = 1; int sync = wake_flags & WF_SYNC; @@ -1490,13 +1490,15 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ * If there's an idle sibling in this domain, make that * the wake_affine target instead of the current cpu. */ - if (tmp->flags & SD_SHARE_PKG_RESOURCES) + if (!cpu_idle && tmp->flags & SD_SHARE_PKG_RESOURCES) target = select_idle_sibling(p, tmp, target); if (target >= 0) { if (tmp->flags & SD_WAKE_AFFINE) { affine_sd = tmp; want_affine = 0; + if (target != cpu) + cpu_idle = 1; } cpu = target; } @@ -1512,6 +1514,7 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ sd = tmp; } +#ifdef CONFIG_FAIR_GROUP_SCHED if (sched_feat(LB_SHARES_UPDATE)) { /* * Pick the largest domain to update shares over @@ -1528,9 +1531,12 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ spin_lock(&rq->lock); } } +#endif - if (affine_sd && wake_affine(affine_sd, p, sync)) - return cpu; + if (affine_sd) { + if (cpu_idle || cpu == prev_cpu || wake_affine(affine_sd, p, sync)) + return cpu; + } while (sd) { int load_idx = sd->forkexec_idx; |