From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46841) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVBCL-0001Il-Gi for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:37:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fVBCI-0007n1-C3 for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:37:05 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:36730 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fVBCI-0007md-7Z for qemu-devel@nongnu.org; Tue, 19 Jun 2018 03:37:02 -0400 Date: Tue, 19 Jun 2018 15:36:50 +0800 From: Peter Xu Message-ID: <20180619073650.GB14814@xz-mi> References: <20180604095520.8563-1-xiaoguangrong@tencent.com> <20180604095520.8563-8-xiaoguangrong@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180604095520.8563-8-xiaoguangrong@tencent.com> Subject: Re: [Qemu-devel] [PATCH 07/12] migration: hold the lock only if it is really needed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: guangrong.xiao@gmail.com Cc: pbonzini@redhat.com, mst@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, kvm@vger.kernel.org, dgilbert@redhat.com, jiang.biao2@zte.com.cn, wei.w.wang@intel.com, Xiao Guangrong On Mon, Jun 04, 2018 at 05:55:15PM +0800, guangrong.xiao@gmail.com wrote: > From: Xiao Guangrong > > Try to hold src_page_req_mutex only if the queue is not > empty Pure question: how much this patch would help? Basically if you are running compression tests then I think it means you are with precopy (since postcopy cannot work with compression yet), then here the lock has no contention at all. Regards, -- Peter Xu