From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38326) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YsYXH-0003RO-6M for qemu-devel@nongnu.org; Wed, 13 May 2015 11:25:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YsYXD-0002bb-4n for qemu-devel@nongnu.org; Wed, 13 May 2015 11:25:27 -0400 Message-ID: <55536CD6.5040008@redhat.com> Date: Wed, 13 May 2015 17:25:10 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <1431538099-3286-1-git-send-email-famz@redhat.com> <1431538099-3286-12-git-send-email-famz@redhat.com> <555326ED.3050609@redhat.com> <20150513110843.GB30644@ad.nay.redhat.com> <5553369C.9010907@redhat.com> <20150513151715.GH30644@ad.nay.redhat.com> In-Reply-To: <20150513151715.GH30644@ad.nay.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 11/11] block: Block "device IO" during bdrv_drain and bdrv_drain_all List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng Cc: Kevin Wolf , qemu-block@nongnu.org, armbru@redhat.com, jcody@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, Stefan Hajnoczi On 13/05/2015 17:17, Fam Zheng wrote: >> > >> > It can be the topic of a separate series. But this patch brings a >> > false sense of security (either the blocker is unnecessary, or it >> > needs to last after bdrv_drain returns), so I think it should be >> > dropped. > Doesn't this let bdrv_drain_all return when virtio-blk-dataplane is having high > workload, in places where you say "the blocker is unnecessary"? Yes, you're right. Please document it in the commit message and the code, it's tricky. Paolo