Messages in this thread Patch in this message | | | From | Valentin Schneider <> | Subject | [PATCH 3/3] sched/fair: Kill wake_cap() | Date | Fri, 24 Jan 2020 12:42:55 +0000 |
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From: Morten Rasmussen <morten.rasmussen@arm.com>
Capacity-awareness in the wake-up path previously involved disabling wake_affine in certain scenarios. We have just made select_idle_sibling() capacity-aware, so this isn't needed anymore.
Remove wake_cap() entirely.
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com> [Changelog tweaks] Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> --- kernel/sched/fair.c | 30 +----------------------------- 1 file changed, 1 insertion(+), 29 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 47a4f52d89b44..e21ce8f2186a4 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6124,33 +6124,6 @@ static unsigned long cpu_util_without(int cpu, struct task_struct *p) return min_t(unsigned long, util, capacity_orig_of(cpu)); } -/* - * Disable WAKE_AFFINE in the case where task @p doesn't fit in the - * capacity of either the waking CPU @cpu or the previous CPU @prev_cpu. - * - * In that case WAKE_AFFINE doesn't make sense and we'll let - * BALANCE_WAKE sort things out. - */ -static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) -{ - long min_cap, max_cap; - - if (!static_branch_unlikely(&sched_asym_cpucapacity)) - return 0; - - min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu)); - max_cap = cpu_rq(cpu)->rd->max_cpu_capacity; - - /* Minimum capacity is close to max, no need to abort wake_affine */ - if (max_cap - min_cap < max_cap >> 3) - return 0; - - /* Bring task utilization in sync with prev_cpu */ - sync_entity_load_avg(&p->se); - - return !task_fits_capacity(p, min_cap); -} - /* * Predicts what cpu_util(@cpu) would return if @p was migrated (and enqueued) * to @dst_cpu. @@ -6415,8 +6388,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f new_cpu = prev_cpu; } - want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu) && - cpumask_test_cpu(cpu, p->cpus_ptr); + want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, p->cpus_ptr); } rcu_read_lock(); -- 2.24.0
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