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=-11.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,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 73777C433E1 for ; Thu, 27 Aug 2020 13:07:43 +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 3B797206F0 for ; Thu, 27 Aug 2020 13:07:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YpCfhOXI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B797206F0 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]:37954 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kBHd0-0002OQ-Go for qemu-devel@archiver.kernel.org; Thu, 27 Aug 2020 09:07:42 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39768) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBHcN-0001eO-JJ for qemu-devel@nongnu.org; Thu, 27 Aug 2020 09:07:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57451) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kBHcK-0001yy-Q7 for qemu-devel@nongnu.org; Thu, 27 Aug 2020 09:07:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598533619; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HWmT8SSGFpzK4FVTZ+cvThQwoe30DX2x2lihZMpGo0o=; b=YpCfhOXIzjotQYp4cYZQAdLHWfx4MvdHEJw4szAVyKBUVU/zKsyiFHeTDX8opKQdLKpgio IhCy6vTmPeSwbYBln5iNZbFszoSR0/LtdwBoFT/iUl5l3mDpM0haTs5llXSMTjHeByjdBr KmIztM6CpOeoMJY9qwNyc8ODYFush/8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-483-W-mBAr5FNXuzlMjN93PFIQ-1; Thu, 27 Aug 2020 09:06:55 -0400 X-MC-Unique: W-mBAr5FNXuzlMjN93PFIQ-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 51A4C802B56; Thu, 27 Aug 2020 13:06:54 +0000 (UTC) Received: from redhat.com (ovpn-114-113.ams2.redhat.com [10.36.114.113]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 419F97E565; Thu, 27 Aug 2020 13:06:48 +0000 (UTC) Date: Thu, 27 Aug 2020 14:06:45 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Denis V. Lunev" Subject: Re: [PATCH 4/6] block, migration: add bdrv_finalize_vmstate helper Message-ID: <20200827130645.GT192458@redhat.com> References: <20200709132644.28470-1-den@openvz.org> <20200709132644.28470-5-den@openvz.org> <20200827125846.GA1429165@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0.003 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/27 02:10:07 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.959, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , Fam Zheng , qemu-block@nongnu.org, Juan Quintela , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Denis Plotnikov , Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Aug 27, 2020 at 04:02:38PM +0300, Denis V. Lunev wrote: > On 8/27/20 3:58 PM, Daniel P. Berrangé wrote: > > On Thu, Jul 09, 2020 at 04:26:42PM +0300, Denis V. Lunev wrote: > >> Right now bdrv_fclose() is just calling bdrv_flush(). > >> > >> The problem is that migration code is working inefficiently from block > >> layer terms and are frequently called for very small pieces of > >> unaligned data. Block layer is capable to work this way, but this is very > >> slow. > >> > >> This patch is a preparation for the introduction of the intermediate > >> buffer at block driver state. It would be beneficial to separate > >> conventional bdrv_flush() from closing QEMU file from migration code. > >> > >> The patch also forces bdrv_finalize_vmstate() operation inside > >> synchronous blk_save_vmstate() operation. This helper is used from > >> qemu-io only. > >> > >> Signed-off-by: Denis V. Lunev > >> Reviewed-by: Vladimir Sementsov-Ogievskiy > >> CC: Kevin Wolf > >> CC: Max Reitz > >> CC: Stefan Hajnoczi > >> CC: Fam Zheng > >> CC: Juan Quintela > >> CC: "Dr. David Alan Gilbert" > >> CC: Denis Plotnikov > >> --- > >> block/block-backend.c | 6 +++++- > >> block/io.c | 15 +++++++++++++++ > >> include/block/block.h | 5 +++++ > >> migration/savevm.c | 4 ++++ > >> 4 files changed, 29 insertions(+), 1 deletion(-) > >> diff --git a/migration/savevm.c b/migration/savevm.c > >> index 45c9dd9d8a..d8a94e312c 100644 > >> --- a/migration/savevm.c > >> +++ b/migration/savevm.c > >> @@ -150,6 +150,10 @@ static ssize_t block_get_buffer(void *opaque, uint8_t *buf, int64_t pos, > >> > >> static int bdrv_fclose(void *opaque, Error **errp) > >> { > >> + int err = bdrv_finalize_vmstate(opaque); > >> + if (err < 0) { > >> + return err; > > This is returning an error without having populating 'errp' which means > > the caller will be missing error diagnosis > > but this behaves exactly like the branch below, > bdrv_flush() could return error too and errp > is not filled in the same way. Doh, it seems the only caller passes NULL for the errp too, so it is a redundant parameter. So nothing wrong with your patch after all. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|