From: Peter Zijlstra <peterz@infradead.org>
To: Alex Shi <alex.shi@linaro.org>
Cc: Mike Galbraith <efault@gmx.de>,
LKML <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Rik van Riel <riel@redhat.com>
Subject: Re: 9908859acaa9 cpuidle/menu: add per CPU PM QoS resume latency consideration
Date: Wed, 22 Feb 2017 15:39:10 +0100 [thread overview]
Message-ID: <20170222143910.GV6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <ac73da0c-4a0d-c36b-9d5a-fe88de3a1acf@linaro.org>
On Wed, Feb 22, 2017 at 10:31:26PM +0800, Alex Shi wrote:
>
>
> On 02/22/2017 09:19 PM, Mike Galbraith wrote:
> > On Wed, 2017-02-22 at 14:12 +0100, Peter Zijlstra wrote:
> >> On Wed, Feb 22, 2017 at 01:56:37PM +0100, Mike Galbraith wrote:
> >>> Hi,
> >>>
> >>> Do we really need a spinlock for that in the idle loop?
> >>
> >> Urgh, that's broken on RT, you cannot schedule the idle loop.
> >
> > That's what made me notice the obnoxious little bugger.
>
> Hi Mike,
>
> Sorry for this bug. Guess the rt_spin_lock call some function in
> rtmutex.c:995. Could you like to show me how to reproduce this bug?
Its not hard; spinlock_t ends up being a mutex, and this is ran from the
idle thread. What thread do you think we ought to run when we block
idle?
next prev parent reply other threads:[~2017-02-22 14:39 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-22 12:56 9908859acaa9 cpuidle/menu: add per CPU PM QoS resume latency consideration Mike Galbraith
2017-02-22 13:12 ` Peter Zijlstra
2017-02-22 13:19 ` Mike Galbraith
2017-02-22 14:31 ` Alex Shi
2017-02-22 14:39 ` Peter Zijlstra [this message]
2017-02-22 14:55 ` Alex Shi
2017-02-23 12:15 ` Rafael J. Wysocki
2017-02-23 13:08 ` Mike Galbraith
2017-02-23 13:58 ` Alex Shi
2017-02-23 13:55 ` Alex Shi
2017-02-23 22:34 ` Rafael J. Wysocki
2017-02-24 1:49 ` Alex Shi
2017-02-24 12:25 ` [PATCH] cpuidle: menu: Avoid taking spinlock for accessing QoS values Rafael J. Wysocki
2017-02-22 14:46 ` 9908859acaa9 cpuidle/menu: add per CPU PM QoS resume latency consideration Mike Galbraith
2017-02-22 14:53 ` Alex Shi
2017-02-22 15:03 ` Mike Galbraith
2017-02-22 15:36 ` Alex Shi
2017-02-22 15:46 ` Mike Galbraith
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