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Date: Wed, 12 Nov 2008 08:57:45 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [patch] Fix block I/O hang.
References: <4919B46C.3040804@redhat.com> <4919B79A.5030402@codemonkey.ws>
	<491AD436.40908@redhat.com>
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To: qemu-devel@nongnu.org

Gerd Hoffmann wrote:
> Anthony Liguori wrote:
>   
>> Gerd Hoffmann wrote:
>>     
>>>   Hi,
>>>
>>> $subject says all.
>>>
>>> please apply,
>>>   Gerd
>>>       
>
>   
>> Under what circumstances?  posix_aio_read() is only invoked from a
>> select callback.  This means there should be data available to be read.
>>     
>
> Well, there are *two* select loops:  main_loop_wait() and
> qemu_aio_wait().  Calling sync block i/o functions from a i/o handler
> causes the two select loops run nested => boom.
>   

Yeah, qemu_aio_wait needs to die.  Can you resubmit your patch with a 
better description, and change the read() look in posix_aio_read() to 
consume as much data as possible before hitting EAGAIN?

Regards,

Anthony Liguori

> cheers,
>   Gerd
>
>
>