linux-kernel - Re: [PATCH] sched: correct testing need_resched in mutex_spin_on

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Message-ID: <1307454624.2322.261.camel@twins>
Date:	Tue, 07 Jun 2011 15:50:24 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Hillf Danton <dhillf@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] sched: correct testing need_resched in
 mutex_spin_on_owner()

On Tue, 2011-06-07 at 15:47 +0200, Peter Zijlstra wrote:
> Only if your above assumption holds, which it doesn't. It explicitly
> checks to see if _this_ cpu needs a resched while spinning, if so it
> bails the spinning and calls schedule in the lock slow path.
> 
> If the owner cpu reschedules, owner will leave the rq and

s/rq/cpu/

> owner_running() will return false, also breaking the loop. 
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