From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55483) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZFhHF-0005ta-PW for qemu-devel@nongnu.org; Thu, 16 Jul 2015 07:24:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZFhH7-0005kJ-Oa for qemu-devel@nongnu.org; Thu, 16 Jul 2015 07:24:33 -0400 Received: from e06smtp15.uk.ibm.com ([195.75.94.111]:34777) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZFhH7-0005hj-Es for qemu-devel@nongnu.org; Thu, 16 Jul 2015 07:24:25 -0400 Received: from /spool/local by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 16 Jul 2015 12:24:21 +0100 Received: from b06cxnps4074.portsmouth.uk.ibm.com (d06relay11.portsmouth.uk.ibm.com [9.149.109.196]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 9BCD61B08023 for ; Thu, 16 Jul 2015 12:25:34 +0100 (BST) Received: from d06av07.portsmouth.uk.ibm.com (d06av07.portsmouth.uk.ibm.com [9.149.37.248]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t6GBOKBV32571568 for ; Thu, 16 Jul 2015 11:24:20 GMT Received: from d06av07.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av07.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t6GBOJq4002220 for ; Thu, 16 Jul 2015 07:24:19 -0400 Message-ID: <55A79463.5070704@de.ibm.com> Date: Thu, 16 Jul 2015 13:24:19 +0200 From: Christian Borntraeger MIME-Version: 1.0 References: <556DBF87.2020908@de.ibm.com> <20150609022832.GA12817@cpc-pc.redhat.com> <5576AB52.8090708@de.ibm.com> <20150610021224.GE10873@ad.nay.redhat.com> <557800E0.5020202@de.ibm.com> <20150610093408.GC11648@ad.nay.redhat.com> <55A78F87.9030805@de.ibm.com> <55A7938A.8000101@redhat.com> In-Reply-To: <55A7938A.8000101@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] "iothread: release iothread around aio_poll" causes random hangs at startup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Fam Zheng Cc: Kevin Wolf , qemu-devel , Stefan Hajnoczi Am 16.07.2015 um 13:20 schrieb Paolo Bonzini: > > > On 16/07/2015 13:03, Christian Borntraeger wrote: >> For what its worth, I can no longer reproduce the issue on >> current master + cherry-pick of a0710f7995f (iothread: release iothread around aio_poll) >> >> bisect tells me that >> >> commit 53ec73e264f481b79b52efcadc9ceb8f8996975c >> Author: Fam Zheng >> AuthorDate: Fri May 29 18:53:14 2015 +0800 >> Commit: Stefan Hajnoczi >> CommitDate: Tue Jul 7 14:27:14 2015 +0100 >> >> block: Use bdrv_drain to replace uncessary bdrv_drain_all >> >> made the problem will blk-null go away. I still dont understand why. > > It could be related to the AioContext problem that I'm fixing these > days, too. Good news, we'll requeue the patch for 2.5. That was also something that I had in mind (in fact I retested this to check the ctx patch). master + cherry-pick of a0710f7995f + revert of 53ec73e26 + this fix still fails, so it was (is?) a different issue. The interesting part is that this problem required 2 or more disk (and we replace drain_all with single drains) so it somewhat sounds plausible. Christian