From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47439) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1adwUz-0005GS-3v for qemu-devel@nongnu.org; Thu, 10 Mar 2016 04:03:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1adwUv-0001VZ-SQ for qemu-devel@nongnu.org; Thu, 10 Mar 2016 04:03:12 -0500 Received: from e06smtp09.uk.ibm.com ([195.75.94.105]:34583) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1adwUv-0001VK-Iw for qemu-devel@nongnu.org; Thu, 10 Mar 2016 04:03:09 -0500 Received: from localhost by e06smtp09.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 10 Mar 2016 09:03:07 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 245541B08072 for ; Thu, 10 Mar 2016 09:03:32 +0000 (GMT) Received: from d06av08.portsmouth.uk.ibm.com (d06av08.portsmouth.uk.ibm.com [9.149.37.249]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u2A935Jr64421984 for ; Thu, 10 Mar 2016 09:03:05 GMT Received: from d06av08.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av08.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u2A935p4030297 for ; Thu, 10 Mar 2016 02:03:05 -0700 References: <1455470231-5223-1-git-send-email-pbonzini@redhat.com> <1455470231-5223-6-git-send-email-pbonzini@redhat.com> <56E01544.6060305@de.ibm.com> <56E01D3F.1060204@redhat.com> <56E03333.5020601@de.ibm.com> <56E04C9B.7070801@redhat.com> <20160310015154.GD23632@ad.usersys.redhat.com> From: Christian Borntraeger Message-ID: <56E13849.3060409@de.ibm.com> Date: Thu, 10 Mar 2016 10:03:05 +0100 MIME-Version: 1.0 In-Reply-To: <20160310015154.GD23632@ad.usersys.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , Paolo Bonzini Cc: Bo Tu , qemu-devel@nongnu.org On 03/10/2016 02:51 AM, Fam Zheng wrote: [...] > The aio_poll() inside "blk_set_aio_context(s->conf->conf.blk, s->ctx)" looks > suspicious: > > main thread iothread > ---------------------------------------------------------------------------- > virtio_blk_handle_output() > virtio_blk_data_plane_start() > vblk->dataplane_started = true; > blk_set_aio_context() > bdrv_set_aio_context() > bdrv_drain() > aio_poll() > > virtio_blk_handle_output() > /* s->dataplane_started is true */ > !!! -> virtio_blk_handle_request() > event_notifier_set(ioeventfd) > aio_poll() > virtio_blk_handle_request() > > Christian, could you try the followed patch? The aio_poll above is replaced > with a "limited aio_poll" that doesn't disptach ioeventfd. > > (Note: perhaps moving "vblk->dataplane_started = true;" after > blk_set_aio_context() also *works around* this.) > > --- > > diff --git a/block.c b/block.c > index ba24b8e..e37e8f7 100644 > --- a/block.c > +++ b/block.c > @@ -4093,7 +4093,9 @@ void bdrv_attach_aio_context(BlockDriverState *bs, > > void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) > { > - bdrv_drain(bs); /* ensure there are no in-flight requests */ > + /* ensure there are no in-flight requests */ > + bdrv_drained_begin(bs); > + bdrv_drained_end(bs); > > bdrv_detach_aio_context(bs); > That seems to do the trick.