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From: Rob Love <rml@tech9.net>
To: Matthias Urlichs <smurf@smurf.noris.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: question about preempt_disable()
Date: Sun, 30 Nov 2003 22:53:41 -0500	[thread overview]
Message-ID: <1070250821.1158.45.camel@localhost> (raw)
In-Reply-To: <pan.2003.11.30.17.39.47.71027@smurf.noris.de>

On Sun, 2003-11-30 at 12:39, Matthias Urlichs wrote:

> You need to prevent deadlocks. Imagine process A grabbing a spinlock, then
> getting preempted. Process B now sits there and waits on the spinlock.
> Forward progress may or may not happen when the scheduler preempts B and
> restarts A, some indeterminate time later.

Further, on uniprocessor systems, we don't have deadlocks so it is the
preempt_disable() that actually ensures concurrency is prevented in the
critical region.

	Rob Love



  reply	other threads:[~2003-12-01  3:53 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-11-30  0:59 question about preempt_disable() Chris Peterson
2003-11-30 17:39 ` Matthias Urlichs
2003-12-01  3:53   ` Rob Love [this message]
2003-12-08 16:31     ` Matthias Urlichs
2003-12-03 23:12 ` George Anzinger

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