From: Christian Borntraeger <kernel@borntraeger.net>
To: joe.korty@ccur.com, dhowells@redhat.com, akpm@osdl.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] volatile may be needed in rwsem
Date: Tue, 27 Jan 2004 21:20:42 +0100 [thread overview]
Message-ID: <200401272120.42675.kernel@borntraeger.net> (raw)
In-Reply-To: <20040127191155.GA12128@tsunami.ccur.com>
Joe Korty wrote:
> 'flags' should be declared volatile as rwsem_down_failed_common() spins
> waiting for this to change. Untested.
You should use barrier() to prevent the compiler from optimizing reads away,
not volatile.
Here the compiler hopefully considers schedule() as a memory barrier. So
everything should be fine.
cheers
Christian
prev parent reply other threads:[~2004-01-27 20:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-27 19:11 [PATCH] volatile may be needed in rwsem Joe Korty
2004-01-27 19:19 ` David Howells
2004-01-27 19:43 ` Joe Korty
2004-01-27 20:23 ` Paulo Marques
2004-01-27 20:20 ` Christian Borntraeger [this message]
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