Messages in this thread Patch in this message | | | Date | Mon, 12 Feb 2018 18:31:47 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 4/4] sched/fair: Do not migrate due to a sync wakeup on exit |
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On Mon, Feb 12, 2018 at 02:58:57PM +0000, Mel Gorman wrote: > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 28c8d9c91955..50442697b455 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5710,8 +5710,14 @@ wake_affine_idle(int this_cpu, int prev_cpu, int sync) > if (idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu)) > return idle_cpu(prev_cpu) ? prev_cpu : this_cpu; > > - if (sync && cpu_rq(this_cpu)->nr_running == 1) > + if (sync && cpu_rq(this_cpu)->nr_running == 1) { > + /* Avoid tasks exiting pulling parents to new nodes */ > + if ((current->flags & PF_EXITING) && > + !cpus_share_cache(this_cpu, prev_cpu)) > + return prev_cpu; > +
Cute, but should we not kill @sync right at the source in this case?
Something a little like this?
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5eb3ffc9be84..568ea4ce5b36 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6342,7 +6342,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f int cpu = smp_processor_id(); int new_cpu = prev_cpu; int want_affine = 0; - int sync = wake_flags & WF_SYNC; + int sync = (wake_flags & WF_SYNC) && !(current->flags & PF_EXITING); if (sd_flag & SD_BALANCE_WAKE) { record_wakee(p);
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