Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}

[Peter Lieven <pl@kamp.de>]

On 25.11.2013 11:54, Paolo Bonzini wrote:
> Il 25/11/2013 11:47, Peter Lieven ha scritto:
>> On 08.10.2013 14:39, Kevin Wolf wrote:
>>> Am 08.10.2013 um 14:35 hat Paolo Bonzini geschrieben:
>>>> Il 08/10/2013 14:33, Kevin Wolf ha scritto:
>>>>>>>>> this converts read, write and flush functions from aio to
>>>>>>>>> coroutines.
>>>>>>> I'm not sure it's already the time for this...  Cancellation sucks in
>>>>>>> QEMU, and this is going to make things even worse.
>>>>> Not sure what you're referring to. If you mean iscsi_aio_cancel(),
>>>>> isn't
>>>>> it dead code anyway since we changed block.c to use coroutines for
>>>>> everything? bdrv_co_io_em() even throws the acb away, so even if you
>>>>> wanted, there's no way to cancel the request even today.
>>>> SCSI tries to use cancellation, and this results in VCPU threads
>>>> starving all other threads.  So I would like to introduce cancellation
>>>> points for coroutines.
>>> Sounds like a nice thing to have, but it's unrelated to this patch.
>>> Cancellation means waiting for request completion before and after the
>>> patch.
>> Can we proceed with the above patch for 1.8?
> Yes, thanks.
Will you pull it or shall I rebase and sent it again after 1.7.0 release?

Peter