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Date: Mon, 18 Dec 2000 21:51:23 +0100
From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>, linux-kernel@vger.kernel.org
Subject: Re: 2.4.0-test13-pre1 lockup: run_task_queue or tty_io are wrong
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In-Reply-To: <Pine.LNX.4.10.10012171200310.25447-100000@penguin.transmeta.com>; from torvalds@transmeta.com on Sun, Dec 17, 2000 at 12:02:31PM -0800
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Linus Torvalds wrote:
> On Sun, 17 Dec 2000, Jamie Lokier wrote:
> > How about using a sentinel list entry representing the current position
> > in run_task_queue's loop?
> 
> Nope.
> 
> There may be multiple concurrent run_task_queue's executing, so for now
> I've applied Andrew Morton's patch that most closely gets the old
> behaviour of having a private list.

I wasn't clear.  The sentinel is a local structure on the stack, and
only exists while run_task_queue is executing.  Another name for this is
"deletion-safe pointer".

It works very nicely with concurrent run_task_queues: each one inserts
its own sentinel and skips over the others.

-- Jamie
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