From: Jiang Biao <benbjiang@gmail.com>
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org
Cc: dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de,
linux-kernel@vger.kernel.org, Jiang Biao <benbjiang@tencent.com>
Subject: [PATCH] sched/fair: avoid vruntime compensation for SCHED_IDLE task
Date: Thu, 20 Aug 2020 20:00:25 +0800 [thread overview]
Message-ID: <20200820120025.74460-1-benbjiang@tencent.com> (raw)
From: Jiang Biao <benbjiang@tencent.com>
Vruntime compensation has been down in place_entity() to
boot the waking procedure for fair tasks. There is no need to
do that for SCHED_IDLE task actually.
Not compensating vruntime for SCHED_IDLE task could make
SCHED_IDLE task more harmless for normal tasks.
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
---
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 1a68a0536add..adff77676a0a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4115,7 +4115,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
vruntime += sched_vslice(cfs_rq, se);
/* sleeps up to a single latency don't count. */
- if (!initial) {
+ if (!initial && likely(!task_has_idle_policy(task_of(se)))) {
unsigned long thresh = sysctl_sched_latency;
/*
--
2.21.0
next reply other threads:[~2020-08-20 12:01 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 12:00 Jiang Biao [this message]
2020-08-20 12:51 ` [PATCH] sched/fair: avoid vruntime compensation for SCHED_IDLE task Vincent Guittot
2020-08-20 12:58 ` peterz
2020-08-20 13:15 ` Vincent Guittot
2020-08-20 13:43 ` peterz
2020-08-20 14:09 ` Vincent Guittot
2020-08-20 14:24 ` Jiang Biao
2020-08-23 7:33 ` Jiang Biao
2020-08-28 12:55 ` Vincent Guittot
2020-09-01 10:14 ` Jiang Biao
2020-09-01 13:04 ` Vincent Guittot
2020-09-01 14:19 ` Jiang Biao
2020-08-20 14:19 ` Jiang Biao
2020-08-20 14:15 ` Jiang Biao
2020-08-21 0:37 ` [sched/fair] 88d13f778f: WARNING:at_kernel/sched/fair.c:#place_entity kernel test robot
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