On 17/06/16 17:18, Peter Zijlstra wrote:
> On Fri, Jun 17, 2016 at 06:02:39PM +0200, Peter Zijlstra wrote:
>> So yes, ho-humm, how to go about doing that bestest. Lemme have a play.
>
> This is what I came up with, not entirely pretty, but I suppose it'll
> have to do.
>
> ---
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -724,6 +724,7 @@ void post_init_entity_util_avg(struct sc
> struct cfs_rq *cfs_rq = cfs_rq_of(se);
> struct sched_avg *sa = &se->avg;
> long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;
> + u64 now = cfs_rq_clock_task(cfs_rq);
>
> if (cap > 0) {
> if (cfs_rq->avg.util_avg != 0) {
> @@ -738,7 +739,20 @@ void post_init_entity_util_avg(struct sc
> sa->util_sum = sa->util_avg * LOAD_AVG_MAX;
> }
>
> - update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, false);
> + if (entity_is_task(se)) {
> + struct task_struct *p = task_of(se);
> + if (p->sched_class != &fair_sched_class) {
> + /*
> + * For !fair tasks do attach_entity_load_avg()
> + * followed by detach_entity_load_avg() as per
> + * switched_from_fair().
> + */
> + se->avg.last_update_time = now;
> + return;
> + }
> + }
> +
> + update_cfs_rq_load_avg(now, cfs_rq, false);
> attach_entity_load_avg(cfs_rq, se);
> }
>
>
Doesn't a sleeping !fair_sched_class task which switches to fair uses
try_to_wake_up() rather than wake_up_new_task() so it won't go through
post_init_entity_util_avg()?
