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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEB55C433EF for ; Fri, 24 Sep 2021 18:03:29 +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 4685A61250 for ; Fri, 24 Sep 2021 18:03:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4685A61250 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:35710 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mTpXk-0004e6-An for qemu-devel@archiver.kernel.org; Fri, 24 Sep 2021 14:03:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55912) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mTpFF-0005vV-P1 for qemu-devel@nongnu.org; Fri, 24 Sep 2021 13:44:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47776) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mTpFD-0002MG-UO for qemu-devel@nongnu.org; Fri, 24 Sep 2021 13:44:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632505459; 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:in-reply-to:in-reply-to: references:references; bh=GFVt9d3ddoom3pnlch+7K8uOMJ+F5px993/UQwC4e24=; b=dbgmEcRCekFnvoNaIZ3ewHgFL74aw2rOhPBNHgQXTKWC+D6m2Y6FWKriUkYtdyc+lqaIUH fC0xnDTmocLzLkcWFzQ20sWSiI3lw5X2+i4YXvIMinGkuxWWgBlAj88uLz0hRAQnpZuIed NNT/941FjGgzXCU48clMfv1xiJr5lDE= 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-551-P1E4Y2S7MPOPl4lJlsDcfw-1; Fri, 24 Sep 2021 13:44:17 -0400 X-MC-Unique: P1E4Y2S7MPOPl4lJlsDcfw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DCE7B1084681 for ; Fri, 24 Sep 2021 17:44:16 +0000 (UTC) Received: from redhat.com (unknown [10.39.192.100]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AB36E60622; Fri, 24 Sep 2021 17:43:51 +0000 (UTC) Date: Fri, 24 Sep 2021 18:43:49 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Leonardo Bras Subject: Re: [PATCH v3 3/3] multifd: Send using asynchronous write on nocomp to send RAM pages. Message-ID: References: <20210922222423.644444-1-leobras@redhat.com> <20210922222423.644444-4-leobras@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210922222423.644444-4-leobras@redhat.com> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 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-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.473, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: qemu-devel@nongnu.org, Jason Wang , "Dr. David Alan Gilbert" , Peter Xu , Juan Quintela Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Sep 22, 2021 at 07:24:23PM -0300, Leonardo Bras wrote: > Change multifd nocomp version to use asynchronous write for RAM pages, and > benefit of MSG_ZEROCOPY when it's available. > > The asynchronous flush happens on cleanup only, before destroying the QIOChannel. > > This will work fine on RAM migration because the RAM pages are not usually freed, > and there is no problem on changing the pages content between async_send() and > the actual sending of the buffer, because this change will dirty the page and > cause it to be re-sent on a next iteration anyway. > > Signed-off-by: Leonardo Bras > --- > migration/multifd.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/migration/multifd.c b/migration/multifd.c > index 377da78f5b..d247207a0a 100644 > --- a/migration/multifd.c > +++ b/migration/multifd.c > @@ -105,7 +105,7 @@ static int nocomp_send_prepare(MultiFDSendParams *p, uint32_t used, > */ > static int nocomp_send_write(MultiFDSendParams *p, uint32_t used, Error **errp) > { > - return qio_channel_writev_all(p->c, p->pages->iov, used, errp); > + return qio_channel_async_writev_all(p->c, p->pages->iov, used, errp); > } This needs to be made conditional so zeroopy is only used if rquested by the mgmt app, and it isn't going to work in all cases (eg TLS) so silently enabling it is not good. > > /** > @@ -546,6 +546,7 @@ void multifd_save_cleanup(void) > MultiFDSendParams *p = &multifd_send_state->params[i]; > Error *local_err = NULL; > > + qio_channel_async_flush(p->c, NULL); > socket_send_channel_destroy(p->c); > p->c = NULL; > qemu_mutex_destroy(&p->mutex); This isn't reliable beucase qio_channel_async_flush will return early even if not everything is flushed. 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 :|