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

[Paolo Bonzini <pbonzini@redhat.com>]

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.

Paolo