Re: [Qemu-devel] [patch] Fix block I/O hang.

[Anthony Liguori]

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
>
>
>