From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [Qemu-devel] [RFC] create a single workqueue for each vm to update vm irq routing table Date: Thu, 28 Nov 2013 12:31:29 +0100 Message-ID: <52972991.1050407@redhat.com> References: <5294BC3B.6070902@redhat.com> <5297050E.6000700@redhat.com> <20131128091903.GA4609@kernel.org> <5297118C.3050104@cloudius-systems.com> <529712A1.8090207@redhat.com> <5297181B.3090109@cloudius-systems.com> <52971D86.60601@redhat.com> <20131128110915.GD5822@minantech.com> <529724B0.80405@redhat.com> <20131128112348.GF5822@minantech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , "Zhanghaoyu (A)" , Gleb Natapov , Avi Kivity , "Huangweidong (C)" , KVM , "Michael S. Tsirkin" , "Jinxin (F)" , Luonengjun , "qemu-devel@nongnu.org" , Zanghongyong To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:27244 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751653Ab3K1Lbo (ORCPT ); Thu, 28 Nov 2013 06:31:44 -0500 In-Reply-To: <20131128112348.GF5822@minantech.com> Sender: kvm-owner@vger.kernel.org List-ID: Il 28/11/2013 12:23, Gleb Natapov ha scritto: >>> > > Unless what ? :) Unless reader is scheduled out? >> > >> > Yes. Or unless my brain is scheduled out in the middle of a sentence. >> > > So we will have to disable preemption in a reader to prevent big latencies for > a writer, no? I don't think that's necessary. The writer itself could also be scheduled out, and the reader critical sections are really small. Let's wait for Zhang to try SRCU and report back. Paolo From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54013) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vlzp3-0006KT-OW for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:31:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Vlzou-0000ez-DW for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:31:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:18884) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Vlzou-0000e1-5d for qemu-devel@nongnu.org; Thu, 28 Nov 2013 06:31:44 -0500 Message-ID: <52972991.1050407@redhat.com> Date: Thu, 28 Nov 2013 12:31:29 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <5294BC3B.6070902@redhat.com> <5297050E.6000700@redhat.com> <20131128091903.GA4609@kernel.org> <5297118C.3050104@cloudius-systems.com> <529712A1.8090207@redhat.com> <5297181B.3090109@cloudius-systems.com> <52971D86.60601@redhat.com> <20131128110915.GD5822@minantech.com> <529724B0.80405@redhat.com> <20131128112348.GF5822@minantech.com> In-Reply-To: <20131128112348.GF5822@minantech.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC] create a single workqueue for each vm to update vm irq routing table List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: Avi Kivity , "Huangweidong (C)" , Gleb Natapov , KVM , "Michael S. Tsirkin" , "Zhanghaoyu (A)" , Luonengjun , "qemu-devel@nongnu.org" , Zanghongyong , Avi Kivity , "Jinxin (F)" Il 28/11/2013 12:23, Gleb Natapov ha scritto: >>> > > Unless what ? :) Unless reader is scheduled out? >> > >> > Yes. Or unless my brain is scheduled out in the middle of a sentence. >> > > So we will have to disable preemption in a reader to prevent big latencies for > a writer, no? I don't think that's necessary. The writer itself could also be scheduled out, and the reader critical sections are really small. Let's wait for Zhang to try SRCU and report back. Paolo