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 E687CC2BCA1 for ; Fri, 7 Jun 2019 19:11:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7516D208C3 for ; Fri, 7 Jun 2019 19:11:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7516D208C3 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 ([::1]:51472 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hZKHE-00049r-Jb for qemu-devel@archiver.kernel.org; Fri, 07 Jun 2019 15:11:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59570) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hZK7J-0005Y0-FP for qemu-devel@nongnu.org; Fri, 07 Jun 2019 15:01:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hZK7H-0003Io-EY for qemu-devel@nongnu.org; Fri, 07 Jun 2019 15:01:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41122) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hZK7C-000379-Nw for qemu-devel@nongnu.org; Fri, 07 Jun 2019 15:01:29 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D11493086262; Fri, 7 Jun 2019 19:01:17 +0000 (UTC) Received: from work-vm (ovpn-116-24.ams2.redhat.com [10.36.116.24]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F28AC7855E; Fri, 7 Jun 2019 19:01:16 +0000 (UTC) Date: Fri, 7 Jun 2019 20:01:14 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Message-ID: <20190607190114.GA2631@work-vm> References: <20190606013138.13312-1-richardw.yang@linux.intel.com> <20190606013138.13312-3-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190606013138.13312-3-richardw.yang@linux.intel.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Fri, 07 Jun 2019 19:01:17 +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 2/2] migration/xbzrle: cleanup the handling cache miss condition X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > For cache miss condition not in last_stage, we need to insert data into > cache. When this step succeed, current_data should be updated. While no > matter these checks pass or not, -1 is returned. > > Based on this, the logic in cache miss handling could be simplified a > little. > > Signed-off-by: Wei Yang > --- > migration/ram.c | 17 ++++++++--------- > 1 file changed, 8 insertions(+), 9 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index 878cd8de7a..67ba075cc4 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1572,15 +1572,14 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data, > if (!cache_is_cached(XBZRLE.cache, current_addr, > ram_counters.dirty_sync_count)) { > xbzrle_counters.cache_miss++; > - if (!last_stage) { > - if (cache_insert(XBZRLE.cache, current_addr, *current_data, > - ram_counters.dirty_sync_count) == -1) { > - return -1; > - } else { > - /* update *current_data when the page has been > - inserted into cache */ > - *current_data = get_cached_data(XBZRLE.cache, current_addr); > - } > + if (!last_stage && > + !cache_insert(XBZRLE.cache, current_addr, *current_data, > + ram_counters.dirty_sync_count)) { > + /* > + * update *current_data when the page has been inserted into > + * cache > + */ > + *current_data = get_cached_data(XBZRLE.cache, current_addr); No this change doesn't gain anything and I find the original easier to read. This function is really subtle, every time I do anything with it I have to think really hard about it, so ease of reading is more important. Dave > } > return -1; > } > -- > 2.19.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK