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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3B7D7C433EF for ; Tue, 5 Jul 2022 08:09:35 +0000 (UTC) Received: from localhost ([::1]:58842 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o8dck-0003vl-9d for qemu-devel@archiver.kernel.org; Tue, 05 Jul 2022 04:09:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60406) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8dZ6-0007jk-CA for qemu-devel@nongnu.org; Tue, 05 Jul 2022 04:05:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:22513) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8dZ4-0008QW-Ai for qemu-devel@nongnu.org; Tue, 05 Jul 2022 04:05:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657008345; 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=D+quiQ6Yfy4DtOgdMyQoOkZrWCr+Wa70UHPy3Vx9m94=; b=QUaug0licpUkRXpOfpJvz8dEsApr/s2lJgjpkxpCpXJTa3iqNxJ71yP2J2Sku+ysGQxfQw 0J/RPv6IaLqYTav+AnOxCPk7JI6HX2YWXutIqgsK1q2DkxBNYPzRrYQ3dBBea9GQJYu4Fd XlpFpbkXENtV/xyRKF3ixDwyL+RZq0k= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-668-07Zo-mhKO425RazzMgmaRg-1; Tue, 05 Jul 2022 04:05:44 -0400 X-MC-Unique: 07Zo-mhKO425RazzMgmaRg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2C6F1801231 for ; Tue, 5 Jul 2022 08:05:44 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F3CF64619F4; Tue, 5 Jul 2022 08:05:42 +0000 (UTC) Date: Tue, 5 Jul 2022 09:05:40 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Leonardo Bras Cc: Juan Quintela , "Dr. David Alan Gilbert" , Eric Blake , Markus Armbruster , Peter Xu , qemu-devel@nongnu.org Subject: Re: [PATCH v3 3/3] migration/multifd: Warn user when zerocopy not working Message-ID: References: <20220704202315.507145-1-leobras@redhat.com> <20220704202315.507145-4-leobras@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220704202315.507145-4-leobras@redhat.com> User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Jul 04, 2022 at 05:23:15PM -0300, Leonardo Bras wrote: > Some errors, like the lack of Scatter-Gather support by the network > interface(NETIF_F_SG) may cause sendmsg(...,MSG_ZEROCOPY) to fail on using > zero-copy, which causes it to fall back to the default copying mechanism. > > After each full dirty-bitmap scan there should be a zero-copy flush > happening, which checks for errors each of the previous calls to > sendmsg(...,MSG_ZEROCOPY). If all of them failed to use zero-copy, then > increment dirty_sync_missed_zero_copy migration stat to let the user know > about it. > > Signed-off-by: Leonardo Bras > --- > migration/ram.h | 2 ++ > migration/multifd.c | 2 ++ > migration/ram.c | 5 +++++ > 3 files changed, 9 insertions(+) Reviewed-by: Daniel P. Berrangé With 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 :|