From: Matt Fleming <matt@codeblueprint.co.uk>
To: Yuyang Du <yuyang.du@intel.com>
Cc: peterz@infradead.org, mingo@kernel.org,
linux-kernel@vger.kernel.org, bsegall@google.com, pjt@google.com,
morten.rasmussen@arm.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com
Subject: Re: [PATCH v5 4/5] sched/fair: Skip detach sched avgs for new task when changing task groups
Date: Tue, 14 Jun 2016 12:38:28 +0100 [thread overview]
Message-ID: <20160614113828.GH2658@codeblueprint.co.uk> (raw)
In-Reply-To: <1465427754-28897-5-git-send-email-yuyang.du@intel.com>
On Thu, 09 Jun, at 07:15:53AM, Yuyang Du wrote:
> 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;
> +
Now that we no longer have the @fork parameter to provide context,
this comment would benefit from some expansion. What about something
like this,
/*
* Newly forked tasks that are being moved between groups
* haven't been enqueued anywhere yet, and don't need detaching.
*/
?
next prev parent reply other threads:[~2016-06-14 11:38 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 ` [PATCH v5 4/5] sched/fair: Skip detach sched avgs for new task when changing task groups Yuyang Du
2016-06-14 11:38 ` Matt Fleming [this message]
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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