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From: Yuyang Du <yuyang.du@intel.com>
To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org
Cc: bsegall@google.com, pjt@google.com, morten.rasmussen@arm.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	matt@codeblueprint.co.uk, Yuyang Du <yuyang.du@intel.com>
Subject: [PATCH v5 4/5] sched/fair: Skip detach sched avgs for new task when changing task groups
Date: Thu,  9 Jun 2016 07:15:53 +0800	[thread overview]
Message-ID: <1465427754-28897-5-git-send-email-yuyang.du@intel.com> (raw)
In-Reply-To: <1465427754-28897-1-git-send-email-yuyang.du@intel.com>

Newly forked task has not been enqueued, so should not be removed from
cfs_rq in task_move_group_fair(). To do so, we identify newly forked
tasks by their sched_avg's last_update_time in detach_entity_load_avg().

Signed-off-by: Yuyang Du <yuyang.du@intel.com>
---
 kernel/sched/fair.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6e870c6..e0f219b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2943,6 +2943,10 @@ static inline void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_en
 
 static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
+	/* Newly forked tasks are not attached yet. */
+	if (!se->avg.last_update_time)
+		return;
+
 	__update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
 			  &se->avg, se->on_rq * scale_load_down(se->load.weight),
 			  cfs_rq->curr == se, NULL);
-- 
1.7.9.5

  parent reply	other threads:[~2016-06-09  7:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-08 23:15 [PATCH v5 0/5] sched/fair: Fix attach and detach sched avgs for task group change and sched class change Yuyang Du
2016-06-08 23:15 ` [PATCH v5 1/5] sched/fair: Clean up attach_entity_load_avg() Yuyang Du
2016-06-14 11:11   ` Matt Fleming
2016-06-14 12:11     ` Peter Zijlstra
2016-06-14 22:18     ` Yuyang Du
2016-06-08 23:15 ` [PATCH v5 2/5] sched/fair: Fix attaching task sched avgs twice when switching to fair or changing task group Yuyang Du
2016-06-08 23:15 ` [PATCH v5 3/5] sched/fair: Move load and util avgs from wake_up_new_task() to sched_fork() Yuyang Du
2016-06-08 23:15 ` Yuyang Du [this message]
2016-06-14 11:38   ` [PATCH v5 4/5] sched/fair: Skip detach sched avgs for new task when changing task groups Matt Fleming
2016-06-14 14:36   ` Peter Zijlstra
2016-06-14 14:45     ` Peter Zijlstra
2016-06-08 23:15 ` [PATCH v5 5/5] sched/fair: Add inline to detach_entity_load_evg() Yuyang Du

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