From b9bae70440d21e106fbc098803b5a190df65f2e0 Mon Sep 17 00:00:00 2001 From: Abel Wu Date: Wed, 7 Sep 2022 19:19:57 +0800 Subject: [PATCH] sched/fair: Avoid double search on same cpu The prev cpu is checked at the beginning of SIS, and it's unlikely to be idle before the second check in select_idle_smt(). So we'd better focus on its SMT siblings. Signed-off-by: Abel Wu Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Josh Don Acked-by: Mel Gorman Link: https://lore.kernel.org/r/20220907112000.1854-3-wuyun.abel@bytedance.com --- kernel/sched/fair.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 9657c7de5f57..1ad79aaaaf93 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6355,6 +6355,8 @@ static int select_idle_smt(struct task_struct *p, int target) int cpu; for_each_cpu_and(cpu, cpu_smt_mask(target), p->cpus_ptr) { + if (cpu == target) + continue; if (available_idle_cpu(cpu) || sched_idle_cpu(cpu)) return cpu; }