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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, T_HK_NAME_DR,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 98A6DC04AB6 for ; Fri, 31 May 2019 16:52:02 +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 70A7926C81 for ; Fri, 31 May 2019 16:52:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 70A7926C81 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]:46396 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWkl7-00086D-LX for qemu-devel@archiver.kernel.org; Fri, 31 May 2019 12:52:01 -0400 Received: from eggs.gnu.org ([209.51.188.92]:43416) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hWkjU-0006TD-29 for qemu-devel@nongnu.org; Fri, 31 May 2019 12:50:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hWkdO-0000Z6-Ix for qemu-devel@nongnu.org; Fri, 31 May 2019 12:44:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59710) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hWkdN-00007B-UA for qemu-devel@nongnu.org; Fri, 31 May 2019 12:44:02 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4A49736807; Fri, 31 May 2019 16:43:49 +0000 (UTC) Received: from work-vm (ovpn-117-254.ams2.redhat.com [10.36.117.254]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5E38E891CE; Fri, 31 May 2019 16:43:40 +0000 (UTC) Date: Fri, 31 May 2019 17:43:37 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang , peterx@redhat.com, quintela@redhat.com Message-ID: <20190531164337.GK3169@work-vm> References: <20190507031703.856-1-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190507031703.856-1-richardw.yang@linux.intel.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Fri, 31 May 2019 16:43:49 +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 Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * 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. Dave > --- > migration/ram.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index 95c51109d2..417874707d 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -3151,12 +3151,7 @@ static int ram_state_init(RAMState **rsp) > qemu_mutex_init(&(*rsp)->src_page_req_mutex); > QSIMPLEQ_INIT(&(*rsp)->src_page_requests); > > - /* > - * Count the total number of pages used by ram blocks not including any > - * gaps due to alignment or unplugs. > - */ > - (*rsp)->migration_dirty_pages = ram_bytes_total() >> TARGET_PAGE_BITS; > - > + (*rsp)->migration_dirty_pages = 0; > ram_state_reset(*rsp); > > return 0; > @@ -3172,7 +3167,6 @@ static void ram_list_init_bitmaps(void) > RAMBLOCK_FOREACH_NOT_IGNORED(block) { > pages = block->max_length >> TARGET_PAGE_BITS; > block->bmap = bitmap_new(pages); > - bitmap_set(block->bmap, 0, pages); > if (migrate_postcopy_ram()) { > block->unsentmap = bitmap_new(pages); > bitmap_set(block->unsentmap, 0, pages); > -- > 2.19.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK