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Date: Fri, 19 Mar 2010 11:53:48 +0900
From: OHMURA Kei <ohmura.kei@lab.ntt.co.jp>
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Subject: [Qemu-devel] Re: virtio_blk_load() question
To: Juan Quintela <quintela@redhat.com>
Cc: ohmura.kei@lab.ntt.co.jp, Yoshiaki Tamura <tamura.yoshiaki@lab.ntt.co.jp>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>, Avi Kivity <avi@redhat.com>

On 2010/03/18 21:07, Juan Quintela wrote:
> Really, ordering doesn't matter (in this case):
> 
> see virtio-blk.c:virtio_blk_dma_restart_bh()
> 
>     QLIST_FOREACH_SAFE(req, &rq_copy, next, next_req) {
>         QLIST_REMOVE(req, next);
>         virtio_blk_handle_request(req, &mrb);
>     }
> 
> This mean that we are just removing from the beggining and addin from
> the beginnig (i.e. reversing).  Adding by the beggining made it easier,
> but I can change if you mean.

Thanks, I understood.
However, since it's difficult to understand this at first glance,
it would be great if you could modify, but I'm OK if you could just add
comments on this to the exiting patch.  It's kind for a newbie like me.


> Notice that except if there are any errors (I was not able to trigger
> it, but didnt' try too hard), that list is going to be syncked in the 
> 
>         qemu_aio_flush();
>         bdrv_flush_all();
> 
> in migrate_fd_put_ready(), so it is not trivial to hit it and probably
> the difference is just theoretical.

Thank you for your information.