From: Oleg Nesterov <oleg@redhat.com>
To: Frank Rowand <frank.rowand@am.sony.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Chris Mason <chris.mason@oracle.com>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mike Galbraith <efault@gmx.de>, tglx <tglx@linutronix.de>
Subject: Re: [PATCH RFC] reduce runqueue lock contention
Date: Wed, 15 Dec 2010 19:59:29 +0100 [thread overview]
Message-ID: <20101215185929.GA18803@redhat.com> (raw)
In-Reply-To: <4D06D968.9070004@am.sony.com>
On 12/13, Frank Rowand wrote:
>
> I have not been able to make sense of the task_running() check in
> try_to_wake_up(), even with that clue. The try_to_wake_up() code in
> question is:
> ...
>
> What am I missing, or is the task_running() test not needed?
I am afraid I can misuderstood this all, including the question ;)
But, with __ARCH_WANT_UNLOCKED_CTXSW task_running() checks ->oncpu.
However, schedule() drops rq->lock after prev was deactivated but
before it clears prev->oncpu.
Oleg.
prev parent reply other threads:[~2010-12-15 19:06 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
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 [this message]
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