From: Vincent Guittot <vincent.guittot@linaro.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
Sargun Dhillon <sargun@sargun.me>
Subject: Re: [PATCH v2] sched/fair: Fix insertion in rq->leaf_cfs_rq_list
Date: Wed, 30 Jan 2019 14:29:42 +0100 [thread overview]
Message-ID: <CAKfTPtBhOomgYONsdfaaVgZCENM+QhfPie2qpu0KyOsvMiog_g@mail.gmail.com> (raw)
In-Reply-To: <20190130132717.GC3103@hirez.programming.kicks-ass.net>
On Wed, 30 Jan 2019 at 14:27, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Wed, Jan 30, 2019 at 02:06:20PM +0100, Peter Zijlstra wrote:
> > On Wed, Jan 30, 2019 at 02:04:10PM +0100, Peter Zijlstra wrote:
>
> > > So I don't much like this; at all. But maybe I misunderstand, this is
> > > somewhat tricky stuff and I've not looked at it in a while.
> > >
> > > So per normal we do:
> > >
> > > enqueue_task_fair()
> > > for_each_sched_entity() {
> > > if (se->on_rq)
> > > break;
> > > enqueue_entity()
> > > list_add_leaf_cfs_rq();
> > > }
> > >
> > > This ensures that all parents are already enqueued, right? because this
> > > is what enqueues those parents.
> > >
> > > And in this case you add an unconditional second
> > > for_each_sched_entity(); even though it is completely redundant, afaict.
> >
> > Ah, it doesn't do a second iteration; it continues where the previous
> > two left off.
> >
> > Still, why isn't this in unthrottle?
>
> Aah, I see, because we need:
>
> rq->tmp_alone_branch == &rq->lead_cfs_rq_list
>
> at the end of enqueue_task_fair(); having had that assertion would've
Yes exactly.
You have been quicker than me to reply
> saved some pain I suppose.
next prev parent reply other threads:[~2019-01-30 13:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 17:18 [PATCH] sched/fair: Fix insertion in rq->leaf_cfs_rq_list Vincent Guittot
2019-01-30 5:22 ` [PATCH v2] " Vincent Guittot
2019-01-30 13:04 ` Peter Zijlstra
2019-01-30 13:06 ` Peter Zijlstra
2019-01-30 13:27 ` Peter Zijlstra
2019-01-30 13:29 ` Vincent Guittot [this message]
2019-01-30 13:40 ` Peter Zijlstra
2019-01-30 15:48 ` Vincent Guittot
2019-01-30 16:58 ` Peter Zijlstra
2019-01-30 14:01 ` Peter Zijlstra
2019-01-30 14:01 ` Peter Zijlstra
2019-01-30 14:27 ` Vincent Guittot
2019-01-30 17:40 ` Vincent Guittot
2019-01-30 14:30 ` Vincent Guittot
2019-02-04 9:03 ` [tip:sched/core] " tip-bot for Vincent Guittot
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAKfTPtBhOomgYONsdfaaVgZCENM+QhfPie2qpu0KyOsvMiog_g@mail.gmail.com \
--to=vincent.guittot@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=sargun@sargun.me \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).