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From: Abel Wu <wuyun.abel@bytedance.com>
To: Peter Zijlstra <peterz@infradead.org>,
	Mel Gorman <mgorman@suse.de>,
	Vincent Guittot <vincent.guittot@linaro.org>
Cc: Josh Don <joshdon@google.com>, Chen Yu <yu.c.chen@intel.com>,
	Yicong Yang <yangyicong@huawei.com>,
	linux-kernel@vger.kernel.org, Abel Wu <wuyun.abel@bytedance.com>
Subject: [PATCH v3 5/5] sched/fair: cleanup for SIS_PROP
Date: Fri,  2 Sep 2022 11:30:32 +0800	[thread overview]
Message-ID: <20220902033032.79846-5-wuyun.abel@bytedance.com> (raw)
In-Reply-To: <20220902033032.79846-1-wuyun.abel@bytedance.com>

The sched-domain of this cpu is only used 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.

Signed-off-by: Abel Wu <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;
 
 		/*
-- 
2.31.1


      parent reply	other threads:[~2022-09-02  3:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-02  3:30 [PATCH v3 1/5] sched/fair: remove redundant check in select_idle_smt Abel Wu
2022-09-02  3:30 ` [PATCH v3 2/5] sched/fair: avoid double search on same cpu Abel Wu
2022-09-02  3:30 ` [PATCH v3 3/5] sched/fair: remove useless check in select_idle_core Abel Wu
2022-09-02  3:30 ` [PATCH v3 4/5] sched/fair: default to false in test_idle_cores Abel Wu
2022-09-02  3:30 ` Abel Wu [this message]

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