From: Peter Zijlstra <peterz@infradead.org>
To: Chris Mason <chris.mason@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>,
axboe@kernel.dk, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] reduce runqueue lock contention
Date: Thu, 20 May 2010 23:23:12 +0200 [thread overview]
Message-ID: <1274390592.1674.1656.camel@laptop> (raw)
In-Reply-To: <1274389786.1674.1653.camel@laptop>
On Thu, 2010-05-20 at 23:09 +0200, Peter Zijlstra wrote:
> int try_to_wake_up(struct task *p, unsigned int mask, wake_flags)
> {
> int state = atomic_read(&p->state);
>
> do {
> if (!(state & mask))
> return 0;
>
> state = atomic_cmpxchg(&p->state, state, TASK_WAKING);
> } while (state != TASK_WAKING);
cpu = select_task_rq()
and then somehow see we get set_task_cpu() done without races :-)
> /* do this pending queue + ipi thing */
>
> return 1;
> }
next prev parent reply other threads:[~2010-05-20 21:23 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-20 20:48 [PATCH RFC] reduce runqueue lock contention Chris Mason
2010-05-20 21:09 ` Peter Zijlstra
2010-05-20 21:23 ` Peter Zijlstra [this message]
2010-05-20 22:17 ` Chris Mason
2010-05-20 22:21 ` Chris Mason
2010-06-04 10:56 ` Stijn Devriendt
2010-06-04 12:00 ` Peter Zijlstra
2010-06-05 9:37 ` Stijn Devriendt
2010-06-21 10:02 ` Peter Zijlstra
2010-06-21 10:54 ` Peter Zijlstra
2010-06-21 13:04 ` Peter Zijlstra
2010-06-22 13:33 ` Peter Zijlstra
2010-06-22 21:11 ` Ingo Molnar
2010-06-23 9:10 ` Peter Zijlstra
2010-12-01 23:13 ` Frank Rowand
2010-12-02 1:17 ` Frank Rowand
2010-12-02 7:36 ` Peter Zijlstra
2010-12-14 2:41 ` Frank Rowand
2010-12-14 3:42 ` Mike Galbraith
2010-12-14 21:42 ` Frank Rowand
2010-12-15 18:59 ` Oleg Nesterov
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