From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABD91C28CC5 for ; Mon, 3 Jun 2019 02:36:29 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 83712279E5 for ; Mon, 3 Jun 2019 02:36:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83712279E5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:56642 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXcpo-0005aL-Q8 for qemu-devel@archiver.kernel.org; Sun, 02 Jun 2019 22:36:28 -0400 Received: from eggs.gnu.org ([209.51.188.92]:43662) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hXcp1-00056r-1I for qemu-devel@nongnu.org; Sun, 02 Jun 2019 22:35:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hXcov-0000Ai-VK for qemu-devel@nongnu.org; Sun, 02 Jun 2019 22:35:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58892) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hXcov-00009u-Pd for qemu-devel@nongnu.org; Sun, 02 Jun 2019 22:35:33 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DC42780F6D; Mon, 3 Jun 2019 02:35:31 +0000 (UTC) Received: from xz-x1 (dhcp-15-205.nay.redhat.com [10.66.15.205]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4726754389; Mon, 3 Jun 2019 02:35:29 +0000 (UTC) Date: Mon, 3 Jun 2019 10:35:27 +0800 From: Peter Xu To: Wei Yang Message-ID: <20190603023527.GD4958@xz-x1> References: <20190507031703.856-1-richardw.yang@linux.intel.com> <20190531164337.GK3169@work-vm> <20190601033441.GB4958@xz-x1> <20190603013305.GA7784@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190603013305.GA7784@richard> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 03 Jun 2019 02:35:31 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH] migratioin/ram: leave RAMBlock->bmap blank on allocating X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jun 03, 2019 at 09:33:05AM +0800, Wei Yang wrote: > On Sat, Jun 01, 2019 at 11:34:41AM +0800, Peter Xu wrote: > >On Fri, May 31, 2019 at 05:43:37PM +0100, Dr. David Alan Gilbert wrote: > >> * Wei Yang (richardw.yang@linux.intel.com) wrote: > >> > During migration, we would sync bitmap from ram_list.dirty_memory to > >> > RAMBlock.bmap in cpu_physical_memory_sync_dirty_bitmap(). > >> > > >> > Since we set RAMBlock.bmap and ram_list.dirty_memory both to all 1, this > >> > means at the first round this sync is meaningless and is a duplicated > >> > work. > >> > > >> > Leaving RAMBlock->bmap blank on allocating would have a side effect on > >> > migration_dirty_pages, since it is calculated from the result of > >> > cpu_physical_memory_sync_dirty_bitmap(). To keep it right, we need to > >> > set migration_dirty_pages to 0 in ram_state_init(). > >> > > >> > Signed-off-by: Wei Yang > >> > >> I've looked at this for a while, and I think it's OK, so > >> > >> Reviewed-by: Dr. David Alan Gilbert > >> > >> Peter, Juan: Can you just see if there's arny reason this would be bad, > >> but I think it's actually more sensible than what we have. > > > >I really suspect it will work in all cases... Wei, have you done any > >test (or better, thorough tests) with this change? My reasoning of > >why we should need the bitmap all set is here: > > > > I have done some migration cases, like migrate a linux guest through tcp. When did you start the migration? Have you tried to migrate during some workload? > > Other cases suggested to do? Could you also help answer the question I raised below in the link? Thanks, > >https://lists.gnu.org/archive/html/qemu-devel/2019-05/msg07361.html -- Peter Xu