From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52709) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VT9oL-0002rI-0h for qemu-devel@nongnu.org; Mon, 07 Oct 2013 08:21:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VT9oF-0002o2-21 for qemu-devel@nongnu.org; Mon, 07 Oct 2013 08:21:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44421) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VT9oE-0002mf-Pk for qemu-devel@nongnu.org; Mon, 07 Oct 2013 08:21:10 -0400 Message-ID: <5252A725.6020700@redhat.com> Date: Mon, 07 Oct 2013 14:20:53 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1378976540-10812-1-git-send-email-stefanha@redhat.com> <1378976540-10812-3-git-send-email-stefanha@redhat.com> <877gdy4gwj.fsf@pixel.localdomain> <4C38C504-350E-4492-89A9-AFF84BAE9836@alex.org.uk> <73208DCACC5648DDB3E030CD@Ximines.local> In-Reply-To: <73208DCACC5648DDB3E030CD@Ximines.local> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 2/3] qemu-timer: make qemu_timer_mod_ns() and qemu_timer_del() thread-safe List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Bligh Cc: Mike Day , Ping Fan Liu , Stefan Hajnoczi , qemu-devel@nongnu.org, Anthony Liguori Il 30/09/2013 15:34, Alex Bligh ha scritto: > > I think the most likely change here is that the walkers might > move outside the BQL. Given modification of this list is so rare, > the lock would be very very read heavy, so RCU is probably a > sensible option. I agree. Keeping the write side on the BQL is sane, but RCU-protecting the read side actually makes the rules simpler. Mike, would you like to give it a shot? Paolo