From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Paolo Bonzini <pbonzini@redhat.com>,
Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
Max Reitz <mreitz@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed
Date: Wed, 17 Sep 2014 23:44:11 +1000 [thread overview]
Message-ID: <5419902B.1030309@ozlabs.ru> (raw)
In-Reply-To: <54195395.9010201@redhat.com>
On 09/17/2014 07:25 PM, Paolo Bonzini wrote:
> Il 17/09/2014 11:06, Stefan Hajnoczi ha scritto:
>> I think the fundamental problem here is that the mirror block job
>> on the source host does not synchronize with live migration.
>
>> Remember the mirror block job iterates on the dirty bitmap
>> whenever it feels like.
>
>> There is no guarantee that the mirror block job has quiesced before
>> migration handover takes place, right?
>
> Libvirt does that. Migration is started only once storage mirroring
> is out of the bulk phase, and the handover looks like:
>
> 1) migration completes
>
> 2) because the source VM is stopped, the disk has quiesced on the source
>
> 3) libvirt sends block-job-complete
>
> 4) libvirt receives BLOCK_JOB_COMPLETED. The disk has now quiesced on
> the destination as well.
>
> 5) the VM is started on the destination
>
> 6) the NBD server is stopped on the destination and the source VM is quit.
>
> It is actually a feature that storage migration is completed
> asynchronously with respect to RAM migration. The problem is that
> qcow2_invalidate_cache happens between (3) and (5), and it doesn't
> like the concurrent I/O received by the NBD server.
How can it happen at all? I thought there are 2 channels/sockets - one for
live migration, one for NBD and they concur, nope?
btw any better idea of a hack to try? Testers are pushing me - they want to
upgrade the broken setup and I am blocking them :) Thanks!
--
Alexey
next prev parent reply other threads:[~2014-09-17 13:44 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-15 10:50 [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed Alexey Kardashevskiy
2014-09-16 12:02 ` Alexey Kardashevskiy
2014-09-16 12:10 ` Paolo Bonzini
2014-09-16 12:34 ` Kevin Wolf
2014-09-16 12:35 ` Paolo Bonzini
2014-09-16 12:52 ` Kevin Wolf
2014-09-16 12:59 ` Paolo Bonzini
2014-09-19 8:47 ` Kevin Wolf
2014-09-23 8:47 ` [Qemu-devel] [RFC PATCH] qcow2: Fix race in cache invalidation Alexey Kardashevskiy
2014-09-24 7:30 ` Alexey Kardashevskiy
2014-09-24 9:48 ` Kevin Wolf
2014-09-25 8:41 ` Alexey Kardashevskiy
2014-09-25 8:57 ` Kevin Wolf
2014-09-25 9:55 ` Alexey Kardashevskiy
2014-09-25 10:20 ` Kevin Wolf
2014-09-25 12:29 ` Alexey Kardashevskiy
2014-09-25 12:39 ` Kevin Wolf
2014-09-25 14:05 ` Alexey Kardashevskiy
2014-09-28 11:14 ` Alexey Kardashevskiy
2014-09-17 6:46 ` [Qemu-devel] migration: qemu-coroutine-lock.c:141: qemu_co_mutex_unlock: Assertion `mutex->locked == 1' failed Alexey Kardashevskiy
2014-09-16 14:52 ` Alexey Kardashevskiy
2014-09-17 9:06 ` Stefan Hajnoczi
2014-09-17 9:25 ` Paolo Bonzini
2014-09-17 13:44 ` Alexey Kardashevskiy [this message]
2014-09-17 15:07 ` Stefan Hajnoczi
2014-09-18 3:26 ` Alexey Kardashevskiy
2014-09-18 9:56 ` Paolo Bonzini
2014-09-19 8:23 ` Alexey Kardashevskiy
2014-09-17 15:04 ` Stefan Hajnoczi
2014-09-17 15:17 ` Eric Blake
2014-09-17 15:53 ` Paolo Bonzini
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