From: Juri Lelli <juri.lelli@arm.com>
To: Daniel Bristot de Oliveira <daolivei@redhat.com>
Cc: linux-kernel@vger.kernel.org, Rik van Riel <riel@redhat.com>,
"Luis Claudio R. Goncalves" <lgoncalv@redhat.com>,
Tejun Heo <tj@kernel.org>, Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org
Subject: Re: [PATCH] cgroup: disable irqs while holding css_set_lock
Date: Tue, 7 Jun 2016 17:11:34 +0100 [thread overview]
Message-ID: <20160607161134.GU9340@e106622-lin> (raw)
In-Reply-To: <494c1f85-bbab-99f1-4095-914aaebdd708@redhat.com>
On 07/06/16 12:26, Daniel Bristot de Oliveira wrote:
> Ciao Juri,
>
> On 06/07/2016 10:30 AM, Juri Lelli wrote:
> > So, this and the partitioned one could actually overlap, since we don't
> > set cpu_exclusive. Is that right?
> >
> > I guess affinity mask of both m processes gets set correclty, but I'm
> > not sure if we are missing one check in the admission control. Can you
> > actually create two overlapping sets and get DEADLINE tasks running in
> > them? For example, what happens if partitioned is [4] and clustered is
> > [4-7]? Does setattr() fail?
>
> That is what I was trying to understand/break. Fortunately, I still
> can't break it! bravo! :-)
>
> In the test you mentioned the task in the "clustered" fails to
> sched_setattr().
>
> Test output example:
> + '[' '!' -d partitioned ']'
> + mkdir partitioned
> + echo 4
> + echo 0
> + echo 0
> + echo 1155
> + cat /proc/self/cpuset
> /partitioned
> + /root/m
> main thread [1162]
> deadline thread started [1164]
Mmm. The other one is good, but this one looks still suspect to me. We
shouldn't have created a new root domain at this point (since
cpu_exclusive is not set), so we shouldn't be able to admit DEADLINE
tasks with a smaller affinity mask than the full root domain mask (which
should still be 0-7 at this point), if I'm interpreting your script correctly
and I'm not wrong about root domains stuff.
Unfortunately I'm not able to test this myself right now. Hopefully next
week.
Thanks a lot for testing, though!
Best,
- Juri
> + '[' '!' -d clustered ']'
> + mkdir clustered
> + echo 4-7
> + echo 0
> + echo 0
> + echo 1
> + echo 1155
> + cat /proc/self/cpuset
> + /root/m
> /clustered
> + /root/m
> main thread [1166]
> sched_setattr: Operation not permitted
>
> I will let you know if I find something odd.
>
> -- Daniel
>
next prev parent reply other threads:[~2016-06-07 16:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 22:24 [PATCH] cgroup: disable irqs while holding css_set_lock Daniel Bristot de Oliveira
2016-06-07 10:14 ` Juri Lelli
2016-06-07 12:39 ` Daniel Bristot de Oliveira
2016-06-07 13:30 ` Juri Lelli
2016-06-07 15:26 ` Daniel Bristot de Oliveira
2016-06-07 16:11 ` Juri Lelli [this message]
2016-06-07 15:13 ` Daniel Bristot de Oliveira
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