The following commit has been merged into the sched/core branch of tip:
Commit-ID: 96c1c0cfe493a7ed549169a6f044bbb83e490fb5
Gitweb: https://git.kernel.org/tip/96c1c0cfe493a7ed549169a6f044bbb83e490fb5
Author: Abel Wu <wuyun.abel@xxxxxxxxxxxxx>
AuthorDate: Wed, 07 Sep 2022 19:20:00 +08:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Wed, 07 Sep 2022 21:53:47 +02:00
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 <wuyun.abel@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Link: https://lore.kernel.org/r/20220907112000.1854-6-wuyun.abel@xxxxxxxxxxxxx
---
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 23b020c..7bad641 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;
/*
|