diff options
| -rw-r--r-- | kernel/sched_fair.c | 82 |
1 files changed, 40 insertions, 42 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 0a413c7e3ab8..cbd8b8a296d1 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1375,29 +1375,48 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) /* * Try and locate an idle CPU in the sched_domain. */ -static int -select_idle_sibling(struct task_struct *p, struct sched_domain *sd, int target) +static int select_idle_sibling(struct task_struct *p, int target) { int cpu = smp_processor_id(); int prev_cpu = task_cpu(p); + struct sched_domain *sd; int i; /* - * If this domain spans both cpu and prev_cpu (see the SD_WAKE_AFFINE - * test in select_task_rq_fair) and the prev_cpu is idle then that's - * always a better target than the current cpu. + * If the task is going to be woken-up on this cpu and if it is + * already idle, then it is the right target. + */ + if (target == cpu && idle_cpu(cpu)) + return cpu; + + /* + * If the task is going to be woken-up on the cpu where it previously + * ran and if it is currently idle, then it the right target. */ - if (target == cpu && !cpu_rq(prev_cpu)->cfs.nr_running) + if (target == prev_cpu && idle_cpu(prev_cpu)) return prev_cpu; /* - * Otherwise, iterate the domain and find an elegible idle cpu. + * Otherwise, iterate the domains and find an elegible idle cpu. */ - for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { - if (!cpu_rq(i)->cfs.nr_running) { - target = i; + for_each_domain(target, sd) { + if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) break; + + for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) { + if (idle_cpu(i)) { + target = i; + break; + } } + + /* + * Lets stop looking for an idle sibling when we reached + * the domain that spans the current cpu and prev_cpu. + */ + if (cpumask_test_cpu(cpu, sched_domain_span(sd)) && + cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) + break; } return target; @@ -1421,7 +1440,7 @@ 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, cpu_idle = !current->pid; + int want_affine = 0; int want_sd = 1; int sync = wake_flags & WF_SYNC; @@ -1460,36 +1479,13 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ } /* - * 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 both cpu and prev_cpu are part of this domain, + * cpu is a valid SD_WAKE_AFFINE target. */ - if (want_affine) { - int target = -1; - - /* - * If both cpu and prev_cpu are part of this domain, - * cpu is a valid SD_WAKE_AFFINE target. - */ - if (cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) - target = cpu; - - /* - * If there's an idle sibling in this domain, make that - * the wake_affine target instead of the current cpu. - */ - 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; - } + if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && + cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { + affine_sd = tmp; + want_affine = 0; } if (!want_sd && !want_affine) @@ -1520,8 +1516,10 @@ select_task_rq_fair(struct rq *rq, struct task_struct *p, int sd_flag, int wake_ #endif if (affine_sd) { - if (cpu_idle || cpu == prev_cpu || wake_affine(affine_sd, p, sync)) - return cpu; + if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) + return select_idle_sibling(p, cpu); + else + return select_idle_sibling(p, prev_cpu); } while (sd) { |