From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NSFAI-00047E-J0
	for qemu-devel@nongnu.org; Tue, 05 Jan 2010 14:34:02 -0500
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1NSFAC-00042p-Rf
	for qemu-devel@nongnu.org; Tue, 05 Jan 2010 14:34:01 -0500
Received: from [199.232.76.173] (port=60630 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NSFAB-00042W-VV
	for qemu-devel@nongnu.org; Tue, 05 Jan 2010 14:33:56 -0500
Received: from mx20.gnu.org ([199.232.41.8]:35695)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <pbonzini@redhat.com>) id 1NSFAB-00050m-IJ
	for qemu-devel@nongnu.org; Tue, 05 Jan 2010 14:33:55 -0500
Received: from mx1.redhat.com ([209.132.183.28])
	by mx20.gnu.org with esmtp (Exim 4.60)
	(envelope-from <pbonzini@redhat.com>) id 1NS4wW-0005k1-9z
	for qemu-devel@nongnu.org; Tue, 05 Jan 2010 03:39:08 -0500
Message-ID: <4B42FAA2.3030403@redhat.com>
Date: Tue, 05 Jan 2010 09:38:58 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] [PATCH 11/19] use a bottom half to run timers
References: <1261382970-23251-1-git-send-email-pbonzini@redhat.com>
	<1261382970-23251-12-git-send-email-pbonzini@redhat.com>
	<4B424E95.4040806@codemonkey.ws>
	<20100104193819.GC13537@shareable.org>
In-Reply-To: <20100104193819.GC13537@shareable.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Jamie Lokier <jamie@shareable.org>
Cc: qemu-devel@nongnu.org

On 01/04/2010 08:38 PM, Jamie Lokier wrote:
> In principle, if it does affect something, it seems likely there is
> already a buggy race condition.  After all, if the timer and bottom
> half could trigger at the same time, which is the condition where the
> order is significant, then in principle the timer could have triggered
> slightly later because it depends on the host alarm behaviour.

No, the problem is when the timer function is _itself_ scheduling a 
bottom half.  Before my patch there was a guarantee that the bh would 
run before TCG, now there is not.  It can be fixed easily though.

Paolo