From 6bec3fbeac4a209f59dea23df3537ce7a53bc313 Mon Sep 17 00:00:00 2001 From: Morten Rasmussen Date: Thu, 6 Feb 2020 19:19:57 +0000 Subject: [PATCH] BACKPORT: sched/fair: Remove wake_cap() 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. Bug: 120440300 Signed-off-by: Morten Rasmussen [Changelog tweaks] Signed-off-by: Valentin Schneider Signed-off-by: Peter Zijlstra (Intel) [Changelog tweaks] Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/20200206191957.12325-5-valentin.schneider@arm.com (cherry picked from commit 25ac227a25ac946e0356772012398cd1710a8bab) [Fixed trivial conflict with 24c44377976e] Signed-off-by: Valentin Schneider Change-Id: Ic91c61ee94c3aa54c573a4cd3fe6882e5fde6335 --- 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 6bf1b755e716..4bc81893a3cf 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6246,33 +6246,6 @@ 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.val; - - /* 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. @@ -6580,8 +6553,7 @@ 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();