From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:44658)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@redhat.com>) id 1UDXf7-0001Ii-ET
	for qemu-devel@nongnu.org; Thu, 07 Mar 2013 05:02:59 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <stefanha@redhat.com>) id 1UDXf4-0005Ge-Rc
	for qemu-devel@nongnu.org; Thu, 07 Mar 2013 05:02:57 -0500
Received: from mx1.redhat.com ([209.132.183.28]:19421)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@redhat.com>) id 1UDXf4-0005GZ-K0
	for qemu-devel@nongnu.org; Thu, 07 Mar 2013 05:02:54 -0500
Received: from int-mx02.intmail.prod.int.phx2.redhat.com
	(int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12])
	by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r27A2seY002221
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK)
	for <qemu-devel@nongnu.org>; Thu, 7 Mar 2013 05:02:54 -0500
Date: Thu, 7 Mar 2013 11:02:52 +0100
From: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20130307100252.GA14726@stefanha-thinkpad.redhat.com>
References: <1362584735-30911-1-git-send-email-stefanha@redhat.com>
	<1362584735-30911-4-git-send-email-stefanha@redhat.com>
	<51377BD5.3060500@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <51377BD5.3060500@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 3/5] aio: add a ThreadPool instance to
	AioContext
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org

On Wed, Mar 06, 2013 at 06:24:37PM +0100, Paolo Bonzini wrote:
> Il 06/03/2013 16:45, Stefan Hajnoczi ha scritto:
> > This patch adds a ThreadPool to AioContext.  It's possible that some
> > AioContext instances will never use the ThreadPool, so defer creation
> > until aio_get_thread_pool().
> 
> What lock should protect against doing this twice?

aio_get_thread_pool() is not thread-safe and I don't think it needs to
be.  I imagine it will only be called from the thread that runs the
AioContext.

Stefan