Re: [Qemu-devel] [PATCH 3/3] linux-aio: process completions from ioq_submit()

[Paolo Bonzini]

On 19/07/2016 13:44, Roman Penyaev wrote:
>>> >>
>>> >> Can this leave I/O stuck if in_queue > 0 && in_flight == 0 after the
>>> >> return from qemu_laio_process_completions?  I think you need to goto the
>>> >> beginning of the function to submit more I/O requests in that case.
> Not quite.  I still leave '&s->e' as set, so we will return in a generic
> qemu_laio_completion_cb(), will do 'event_notifier_test_and_clear(&s->e)'
> and again will process events with normal submission.
> 
> IMHO this is better variant than spinning inside ioq_submit doing goto.
> We do not occupy the whole events processing for our IO needs and give
> a chance to complete other stuff.  But of course this is guts feeling
> and I do not have any serious numbers.

That's fine as long as it doesn't hang. :)

Paolo