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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 7B163C47080 for ; Tue, 1 Jun 2021 21:32:48 +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 2DA1D613B9 for ; Tue, 1 Jun 2021 21:32:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DA1D613B9 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]:59244 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1loC0F-0001DJ-8d for qemu-devel@archiver.kernel.org; Tue, 01 Jun 2021 17:32:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58702) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1loByj-0008Qe-Ev for qemu-devel@nongnu.org; Tue, 01 Jun 2021 17:31:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30410) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1loByh-0001ze-No for qemu-devel@nongnu.org; Tue, 01 Jun 2021 17:31:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622583071; h=from:from: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=2H/S+9JIalK/y8vjdClmsCMGpy/orLzUo2GXYQD0cDY=; b=Fr0APA5DejyZtCZRIyEhz4hNLUxOo8APQZmn0L/q7nSNr3D6+tjBwhYl3XY9DK9M2vJeau jk7CDsDyP5RCvMJzapoIHboKJ1VEBU3PaPLUPV7dFJ7eVBPP23cPW+jfdtMXNT4s56VvdG s18CpxxB/MGv9spiQzDVnOwu6zxKdTM= 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-423-18fVvN3COdS_13v0NxQArA-1; Tue, 01 Jun 2021 17:31:09 -0400 X-MC-Unique: 18fVvN3COdS_13v0NxQArA-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 693B01009446; Tue, 1 Jun 2021 21:31:08 +0000 (UTC) Received: from redhat.com (ovpn-113-154.phx2.redhat.com [10.3.113.154]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1FAAE5C1C4; Tue, 1 Jun 2021 21:31:02 +0000 (UTC) Date: Tue, 1 Jun 2021 16:31:01 -0500 From: Eric Blake To: Sergio Lopez Subject: Re: [PATCH 2/2] nbd/server: Use drained block ops to quiesce the server Message-ID: <20210601213101.xqz7os5kje56vi3i@redhat.com> References: <20210601055728.90849-1-slp@redhat.com> <20210601055728.90849-3-slp@redhat.com> <20210601163129.wcx5li7lkdvxrxgi@mhamilton> MIME-Version: 1.0 In-Reply-To: <20210601163129.wcx5li7lkdvxrxgi@mhamilton> User-Agent: NeoMutt/20210205 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.371, 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_H4=0.001, RCVD_IN_MSPIKE_WL=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: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Nir Soffer Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jun 01, 2021 at 06:31:29PM +0200, Sergio Lopez wrote: > > Hm, how do you get more than one coroutine per client yielding in > > nbd_read_eof() at the same time? I thought the model is that you always > > have one coroutine reading the next request (which is > > client->recv_coroutine) and all the others are just processing the > > request they had read earlier. Multiple coroutines reading from the > > same socket would sound like a bad idea. > > You're right, there's only a single coroutine yielding on > nbd_read_eof(). I've added the list while at a moment I was trying to > keep track of every coroutine, and I kept it without thinking if it > was really needed. > > I'll drop it, entering just client->recv_coroutine is it isn't NULL. Sounds like I'll wait for the v2 before applying. But the overall logic changes made sense to me. > > The patch looks correct to me, though I'm not sure if yield_co_list is > > an unnecessary complication (and if it isn't, whether that's safe). > > > > I would be happy enough to apply it anyway if you can explain the > > yield_co_list thing, but I'll give Eric some time to have a look, too. Thanks for catching my attention on this! -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org