From: Vincent Guittot <vincent.guittot@linaro.org>
To: "Guilherme G. Piccoli" <gpiccoli@canonical.com>
Cc: Tao Zhou <t1zhou@163.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
Sasha Levin <sashal@kernel.org>,
SeongJae Park <sjpark@amazon.com>,
Ben Segall <bsegall@google.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Tao Zhou <zohooouoto@zoho.com.cn>, Mel Gorman <mgorman@suse.de>,
Ingo Molnar <mingo@redhat.com>, Tao Zhou <ouwen210@hotmail.com>,
Phil Auld <pauld@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Pavan Kondeti <pkondeti@codeaurora.org>,
Steven Rostedt <rostedt@goodmis.org>,
Jay Vosburgh <jay.vosburgh@canonical.com>,
Gavin Guo <gavin.guo@canonical.com>,
halves@canonical.com, nivedita.singhvi@canonical.com,
linux-kernel <linux-kernel@vger.kernel.org>,
"# v4 . 16+" <stable@vger.kernel.org>
Subject: Re: [PATCH v3] sched/fair: fix unthrottle_cfs_rq for leaf_cfs_rq list
Date: Thu, 19 Nov 2020 14:25:05 +0100 [thread overview]
Message-ID: <CAKfTPtAfzxbm0qM+8r2i+3jWjpJ2OLbU4F1WE8GrzTZH6Ck7FA@mail.gmail.com> (raw)
In-Reply-To: <7c9462c9-8908-8592-0727-9117d4173724@canonical.com>
On Thu, 19 Nov 2020 at 12:36, Guilherme G. Piccoli
<gpiccoli@canonical.com> wrote:
>
>
>
> On 19/11/2020 05:36, Vincent Guittot wrote:
> > On Thu, 19 Nov 2020 at 01:36, Tao Zhou <t1zhou@163.com> wrote:
> >>
> >> On Thu, Nov 19, 2020 at 07:50:15AM +0800, Tao Zhou wrote:
> >>> On Wed, Nov 18, 2020 at 07:56:38PM -0300, Guilherme G. Piccoli wrote:
> >>>> Hi Vincent (and all CCed), I'm sorry to ping about such "old" patch, but
> >>>> we experienced a similar condition to what this patch addresses; it's an
> >>>> older kernel (4.15.x) but when suggesting the users to move to an
> >>>> updated 5.4.x kernel, we noticed that this patch is not there, although
> >>>> similar ones are (like [0] and [1]).
> >>>>
> >>>> So, I'd like to ask if there's any particular reason to not backport
> >>>> this fix to stable kernels, specially the longterm 5.4. The main reason
> >>>> behind the question is that the code is very complex for non-experienced
> >>>> scheduler developers, and I'm afraid in suggesting such backport to 5.4
> >>>> and introduce complex-to-debug issues.
> >>>>
> >>>> Let me know your thoughts Vincent (and all CCed), thanks in advance.
> >>>> Cheers,
> >>>>
> >>>>
> >>>> Guilherme
> >>>>
> >>>>
> >>>> P.S. For those that deleted this thread from the email client, here's a
> >>>> link:
> >>>> https://lore.kernel.org/lkml/20200513135528.4742-1-vincent.guittot@linaro.org/
> >>>>
> >>>>
> >>>> [0]
> >>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fe61468b2cb
> >>>>
> >>>> [1]
> >>>> https://lore.kernel.org/lkml/20200506141821.GA9773@lorien.usersys.redhat.com/
> >>>> <- great thread BTW!
> >>>
> >>> 'sched/fair: Fix unthrottle_cfs_rq() for leaf_cfs_rq list" failed to apply to
> >>> 5.4-stable tree'
> >>>
> >>> You could check above. But I do not have the link about this. Can't search it
> >>> on LKML web: https://lore.kernel.org/lkml/
> >>>
> >>> BTW: 'ouwen210@hotmail.com' and 'zohooouoto@zoho.com.cn' all is myself.
> >>>
> >>> Sorry for the confusing..
> >>>
> >>> Thanks.
> >>
> >> Sorry again. I forget something. It is in the stable.
> >>
> >> Here it is:
> >>
> >> https://lore.kernel.org/stable/159041776924279@kroah.com/
> >
> > I think it has never been applied to stable.
> > As you mentioned, the backport has been sent :
> > https://lore.kernel.org/stable/20200525172709.GB7427@vingu-book/
> >
> > I received another emailed in September and pointed out to the
> > backport : https://www.spinics.net/lists/stable/msg410445.html
> >
> >
> >>
>
> Thanks a lot Tao and Vincent! Nice to know that you already worked the
> backport, gives much more confidence when the author does that heheh
>
> So, this should go to stable 5.4.y, but not 4.19.y IIUC?
Yeah. they should be backported up to v5.1 but not earlier
Regards,
Vincent
> Cheers,
>
>
> Guilherme
next prev parent reply other threads:[~2020-11-19 13:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <17fc60a3-cc50-7cff-eb46-904c2f0c416e@canonical.com>
[not found] ` <20201118235015.GB6015@geo.homenetwork>
[not found] ` <20201119003319.GA6805@geo.homenetwork>
2020-11-19 8:36 ` [PATCH v3] sched/fair: fix unthrottle_cfs_rq for leaf_cfs_rq list Vincent Guittot
2020-11-19 11:34 ` Guilherme G. Piccoli
2020-11-19 13:25 ` Vincent Guittot [this message]
2020-11-19 14:07 ` Guilherme Piccoli
2021-06-24 10:29 ` Po-Hsu Lin
2021-06-24 12:31 ` Vincent Guittot
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