From: Mel Gorman <mgorman@techsingularity.net>
To: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Song Bao Hua <song.bao.hua@hisilicon.com>,
LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>
Subject: [PATCH 2/2] sched/fair: Avoid a second scan of target in select_idle_cpu
Date: Wed, 4 Aug 2021 12:58:57 +0100 [thread overview]
Message-ID: <20210804115857.6253-3-mgorman@techsingularity.net> (raw)
In-Reply-To: <20210804115857.6253-1-mgorman@techsingularity.net>
When select_idle_cpu starts scanning for an idle CPU, it starts with
a target CPU that has already been checked by select_idle_sibling.
This patch starts with the next CPU instead.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8ad7666f387c..f412b4504378 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6249,7 +6249,7 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, bool
time = cpu_clock(this);
}
- for_each_cpu_wrap(cpu, cpus, target) {
+ for_each_cpu_wrap(cpu, cpus, target + 1) {
if (has_idle_core) {
i = select_idle_core(p, cpu, cpus, &idle_cpu);
if ((unsigned int)i < nr_cpumask_bits)
--
2.31.1
next prev parent reply other threads:[~2021-08-04 11:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-04 11:58 [PATCH 0/2] Reduce SIS scanning Mel Gorman
2021-08-04 11:58 ` [PATCH 1/2] sched/fair: Use prev instead of new target as recent_used_cpu Mel Gorman
2021-08-05 9:34 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2021-08-04 11:58 ` Mel Gorman [this message]
2021-08-05 9:34 ` [tip: sched/core] sched/fair: Avoid a second scan of target in select_idle_cpu tip-bot2 for Mel Gorman
2021-08-04 13:11 ` [PATCH 0/2] Reduce SIS scanning Peter Zijlstra
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