From: Peter Zijlstra commit fe3bcfe1f6c1fc4ea7706ac2d05e579fd9092682 upstream 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 Cc: Mike Galbraith LKML-Reference: <20091112145610.909723612@chello.nl> Signed-off-by: Ingo Molnar Signed-off-by: Mike Galbraith Signed-off-by: Greg Kroah-Hartman --- kernel/sched_fair.c | 33 ++++++++++++++++----------------- 1 file changed, 16 insertions(+), 17 deletions(-) --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1398,20 +1398,16 @@ select_idle_sibling(struct task_struct * * test in select_task_rq_fair) and the prev_cpu is idle then that's * always a better target than the current cpu. */ - if (target == cpu) { - if (!cpu_rq(prev_cpu)->cfs.nr_running) - target = prev_cpu; - } + if (target == cpu && !cpu_rq(prev_cpu)->cfs.nr_running) + return prev_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) { - if (!cpu_rq(i)->cfs.nr_running) { - target = i; - break; - } + for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { + if (!cpu_rq(i)->cfs.nr_running) { + target = i; + break; } } @@ -1475,7 +1471,12 @@ select_task_rq_fair(struct rq *rq, struc 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; /* @@ -1488,17 +1489,15 @@ select_task_rq_fair(struct rq *rq, struc /* * If there's an idle sibling in this domain, make that * 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) target = select_idle_sibling(p, tmp, target); if (target >= 0) { - affine_sd = tmp; - want_affine = 0; + if (tmp->flags & SD_WAKE_AFFINE) { + affine_sd = tmp; + want_affine = 0; + } cpu = target; } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/