From: Peter Zijlstra <peterz@infradead.org>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Yuyang Du <yuyang.du@intel.com>,
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 1/5] sched/fair: Clean up attach_entity_load_avg()
Date: Tue, 14 Jun 2016 14:11:33 +0200 [thread overview]
Message-ID: <20160614121133.GF30921@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160614111152.GG2658@codeblueprint.co.uk>
On Tue, Jun 14, 2016 at 12:11:52PM +0100, Matt Fleming wrote:
> On Thu, 09 Jun, at 07:15:50AM, Yuyang Du wrote:
> > attach_entity_load_avg() is called (indirectly) from:
> >
> > - switched_to_fair(): switch between classes to fair
> > - task_move_group_fair(): move between task groups
> > - enqueue_entity_load_avg(): enqueue entity
> >
> > Only in switched_to_fair() is it possible that the task's last_update_time
> > is not 0 and therefore the task needs sched avgs update, so move the task
> > sched avgs update to switched_to_fair() only. In addition, the code is
> > refactored and code comments are updated.
> >
> > No functionality change.
> >
> > Signed-off-by: Yuyang Du <yuyang.du@intel.com>
> > ---
> > kernel/sched/fair.c | 43 ++++++++++++++++++++-----------------------
> > 1 file changed, 20 insertions(+), 23 deletions(-)
>
> Looks OK to me and makes the code easier to understand. Chasing
> ->avg.last_update_time values is tricky at the best of times.
>
> Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
So I still wonder at the point of this patch, since the next patch
deletes this code entirely. What's the point of cleaning it up if the
next patch removes it out-right.
next prev parent reply other threads:[~2016-06-14 12:11 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 [this message]
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
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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