From: Yuyang Du <yuyang.du@intel.com>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, dietmar.eggemann@arm.com
Subject: Re: [PATCH v3] sched: fix first task of a task group is attached twice
Date: Thu, 16 Jun 2016 03:19:15 +0800 [thread overview]
Message-ID: <20160615191914.GM8105@intel.com> (raw)
In-Reply-To: <1464623541-25429-1-git-send-email-vincent.guittot@linaro.org>
On Mon, May 30, 2016 at 05:52:20PM +0200, Vincent Guittot wrote:
> The cfs_rq->avg.last_update_time is initialize to 0 with the main effect
> that the 1st sched_entity that will be attached, will keep its
> last_update_time set to 0 and will attached once again during the
> enqueue.
> Initialize cfs_rq->avg.last_update_time to 1 instead.
>
> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
>
> v3:
> - add initialization of load_last_update_time_copy for not 64bits system
> - move init into init_cfs_rq
>
> v2:
> - rq_clock_task(rq_of(cfs_rq)) can't be used because lock is not held
>
> kernel/sched/fair.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 218f8e8..86be9c1 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8459,6 +8459,16 @@ void init_cfs_rq(struct cfs_rq *cfs_rq)
> cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime;
> #endif
> #ifdef CONFIG_SMP
> + /*
> + * Set last_update_time to something different from 0 to make
> + * sure the 1st sched_entity will not be attached twice: once
> + * when attaching the task to the group and one more time when
> + * enqueueing the task.
> + */
> + cfs_rq->avg.last_update_time = 1;
> +#ifndef CONFIG_64BIT
> + cfs_rq->load_last_update_time_copy = 1;
> +#endif
> atomic_long_set(&cfs_rq->removed_load_avg, 0);
> atomic_long_set(&cfs_rq->removed_util_avg, 0);
> #endif
Then, when enqueued, both cfs_rq and task will be decayed to 0, due to
a large gap between 1 and now, no?
next prev parent reply other threads:[~2016-06-16 3:16 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-24 13:08 [PATCH] sched: fix first task of a task group is attached twice Vincent Guittot
2016-05-25 15:01 ` [PATCH v2] " Vincent Guittot
2016-05-25 22:38 ` Yuyang Du
2016-05-26 8:26 ` Vincent Guittot
2016-05-26 0:40 ` Yuyang Du
2016-05-26 8:51 ` Vincent Guittot
2016-05-27 15:48 ` Dietmar Eggemann
2016-05-27 17:16 ` Vincent Guittot
2016-05-27 20:38 ` Dietmar Eggemann
2016-05-30 7:04 ` Vincent Guittot
2016-05-30 15:52 ` [PATCH v3] " Vincent Guittot
2016-05-30 19:48 ` Yuyang Du
2016-05-31 7:28 ` Vincent Guittot
2016-05-31 0:44 ` Yuyang Du
2016-06-01 15:31 ` Dietmar Eggemann
2016-06-01 15:54 ` Vincent Guittot
2016-06-06 19:32 ` Dietmar Eggemann
2016-06-07 7:35 ` Vincent Guittot
2016-06-15 19:19 ` Yuyang Du [this message]
2016-06-16 7:12 ` Vincent Guittot
2016-06-15 23:24 ` Yuyang Du
2016-06-16 9:42 ` Vincent Guittot
2016-05-30 15:54 ` [PATCH v2] " Vincent Guittot
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