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Date: Thu, 07 Oct 2010 16:04:05 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] ceph/rbd block driver for qemu-kvm (v4)
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To: Yehuda Sadeh Weinraub <yehudasa@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, ceph-devel@vger.kernel.org, qemu-devel@nongnu.org, kvm@vger.kernel.org, Christian Brunner <chb@muc.de>

On 10/07/2010 03:47 PM, Yehuda Sadeh Weinraub wrote:
>> How is that possible?  Are the callbacks delivered in the context of a
>> different thread?  If so, don't you need locking?
>>      
> Not sure I'm completely following you. The callbacks are delivered in
> the context of a different thread, but won't run concurrently.

Concurrently to what?  How do you prevent them from running concurrently 
with qemu?

If you saw lock ups, I bet that's what it was from.

Regards,

Anthony Liguori

>   Do you
> see any specific concurrency issue? We can add some mutex protection
> around at the aio callback, so that if librados turns multithreaded at
> this point we're covered.
>
>
> Thanks,
> Yehuda
>
>