From 96c1c0cfe493a7ed549169a6f044bbb83e490fb5 Mon Sep 17 00:00:00 2001 From: Abel Wu Date: Wed, 7 Sep 2022 19:20:00 +0800 Subject: [PATCH] sched/fair: Cleanup for SIS_PROP The sched-domain of this cpu is only used for some heuristics when SIS_PROP is enabled, and it should be irrelevant whether the local sd_llc is valid or not, since all we care about is target sd_llc if !SIS_PROP. Access the local domain only when there is a need. Signed-off-by: Abel Wu Signed-off-by: Peter Zijlstra (Intel) Acked-by: Mel Gorman Link: https://lore.kernel.org/r/20220907112000.1854-6-wuyun.abel@bytedance.com --- kernel/sched/fair.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 23b020c3d3a0..7bad641faef9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6396,19 +6396,19 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool struct sched_domain_shared *sd_share; struct rq *this_rq = this_rq(); int this = smp_processor_id(); - struct sched_domain *this_sd; + struct sched_domain *this_sd = NULL; u64 time = 0; - this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); - if (!this_sd) - return -1; - cpumask_and(cpus, sched_domain_span(sd), p->cpus_ptr); if (sched_feat(SIS_PROP) && !has_idle_core) { u64 avg_cost, avg_idle, span_avg; unsigned long now = jiffies; + this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc)); + if (!this_sd) + return -1; + /* * If we're busy, the assumption that the last idle period * predicts the future is flawed; age away the remaining @@ -6462,7 +6462,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool if (has_idle_core) set_idle_cores(target, false); - if (sched_feat(SIS_PROP) && !has_idle_core) { + if (sched_feat(SIS_PROP) && this_sd && !has_idle_core) { time = cpu_clock(this) - time; /* -- 2.25.1