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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 73009C4321A for ; Fri, 28 Jun 2019 23:06:23 +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 4403C2086D for ; Fri, 28 Jun 2019 23:06:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4403C2086D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:36828 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgzwj-0007Y0-R0 for qemu-devel@archiver.kernel.org; Fri, 28 Jun 2019 19:06:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48885) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgzvY-0006mX-7X for qemu-devel@nongnu.org; Fri, 28 Jun 2019 19:05:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hgzvX-0002qE-60 for qemu-devel@nongnu.org; Fri, 28 Jun 2019 19:05:08 -0400 Received: from mga05.intel.com ([192.55.52.43]:52074) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hgzvW-0002fm-SZ for qemu-devel@nongnu.org; Fri, 28 Jun 2019 19:05:07 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 Jun 2019 16:05:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,429,1557212400"; d="scan'208";a="167896451" Received: from richard.sh.intel.com (HELO localhost) ([10.239.159.54]) by orsmga006.jf.intel.com with ESMTP; 28 Jun 2019 16:04:59 -0700 Date: Sat, 29 Jun 2019 07:04:36 +0800 From: Wei Yang To: "Dr. David Alan Gilbert" Message-ID: <20190628230436.GA8241@richard> References: <20190627020822.15485-1-richardw.yang@linux.intel.com> <20190627020822.15485-2-richardw.yang@linux.intel.com> <20190628150950.GG2922@work-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190628150950.GG2922@work-vm> User-Agent: Mutt/1.10.1 (2018-07-13) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 192.55.52.43 Subject: Re: [Qemu-devel] [PATCH 1/3] migration/postcopy: the valid condition is one less then end 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: , Reply-To: Wei Yang Cc: quintela@redhat.com, Wei Yang , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Jun 28, 2019 at 04:09:50PM +0100, Dr. David Alan Gilbert wrote: >* Wei Yang (richardw.yang@linux.intel.com) wrote: >> If one equals end, it means we have gone through the whole bitmap. >> >> Use a more restrict check to skip a unnecessary condition. >> >> Signed-off-by: Wei Yang > >Yes, I don't think that'll break, since I think the find_next_zero_bit >will also return end, and then discard_length would be 0; still I think >it's a correct fix. Yep, you are exactly right. > >Reviewed-by: Dr. David Alan Gilbert > >> --- >> migration/ram.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/migration/ram.c b/migration/ram.c >> index 908517fc2b..b78169e811 100644 >> --- a/migration/ram.c >> +++ b/migration/ram.c >> @@ -2777,7 +2777,7 @@ static int postcopy_send_discard_bm_ram(MigrationState *ms, >> for (current = 0; current < end; ) { >> unsigned long one = find_next_bit(unsentmap, end, current); >> >> - if (one <= end) { >> + if (one < end) { >> unsigned long zero = find_next_zero_bit(unsentmap, end, one + 1); >> unsigned long discard_length; >> >> -- >> 2.19.1 >> >-- >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK -- Wei Yang Help you, Help me