From: Peter Zijlstra <peterz@infradead.org>
To: "Arve Hjønnevåg" <arve@android.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
Riley Andrews <riandrews@android.com>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Todd Kjos <tkjos@google.com>
Subject: Re: [PATCH] android: binder: Disable preemption while holding the global binder lock
Date: Wed, 14 Sep 2016 18:11:03 +0200 [thread overview]
Message-ID: <20160914161103.GC5016@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMP5Xgc89ZONamzB4gmnH3RjW5rDSwh3Akrx30npfTiZ1qGzWg@mail.gmail.com>
On Tue, Sep 13, 2016 at 12:53:27PM -0700, Arve Hjønnevåg wrote:
> On Tue, Sep 13, 2016 at 12:32 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > cgroups should be irrelevant, PI is unaware of them.
>
> I don't think cgroups are irrelevant. PI being unaware of them
> explains the problem I described. If the task that holds the lock is
> in a cgroup that has a low cpu.shares value, then boosting the task's
> priority within that group does necessarily make it any more likely to
> run.
Thing is, for FIFO/DL the important parameters (prio and deadline resp.)
are not cgroup dependent.
For CFS you're right, and as per usual, cgroups will be a royal pain.
While we can compute the total weight in the block chain, getting that
back to a task which is stuck in a cgroup is just not going to work
well.
The only 'solution' I can come up with in a hurry is, when the task is
boosted, move it to the root cgroup. That of course has a whole heap of
problems all on its own.
/me curses @ cgroups.. bloody stupid things.
next prev parent reply other threads:[~2016-09-14 16:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-08 16:12 [PATCH] android: binder: Disable preemption while holding the global binder lock Todd Kjos
2016-09-08 16:15 ` Todd Kjos
2016-09-08 17:46 ` Greg Kroah-Hartman
2016-09-10 16:16 ` Christoph Hellwig
2016-09-10 16:22 ` Peter Zijlstra
2016-09-10 16:37 ` Thomas Gleixner
2016-09-10 17:28 ` Greg Kroah-Hartman
2016-09-12 15:49 ` Todd Kjos
2016-09-13 3:44 ` Arve Hjønnevåg
2016-09-13 6:42 ` Greg Kroah-Hartman
2016-09-13 19:52 ` Arve Hjønnevåg
2016-09-13 7:32 ` Peter Zijlstra
2016-09-13 19:53 ` Arve Hjønnevåg
2016-09-14 7:10 ` Peter Zijlstra
2016-09-14 7:41 ` Peter Zijlstra
2016-09-14 13:38 ` Peter Zijlstra
2016-09-14 16:11 ` Peter Zijlstra [this message]
2016-09-14 16:13 ` Peter Zijlstra
2016-09-14 16:55 ` Peter Zijlstra
2016-09-17 0:42 ` Todd Kjos
-- strict thread matches above, loose matches on Subject: below --
2016-09-09 15:17 Todd Kjos
2016-09-09 15:44 ` Greg KH
2016-09-09 17:39 ` Todd Kjos
2016-09-10 11:18 ` Greg KH
2016-09-10 11:25 ` Greg KH
2016-09-10 11:25 ` Greg KH
2016-09-09 16:37 ` kbuild test robot
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