Re: [Qemu-devel] [PATCH v2 1/1] coroutine-lock: do not touch coroutine after another one has been entered

[Roman Penyaev]

On Wed, May 31, 2017 at 3:22 PM, Paolo Bonzini <address@hidden> wrote:
>
>
> On 31/05/2017 15:06, Stefan Hajnoczi wrote:
>>> +
>>> +    while ((next = QSIMPLEQ_FIRST(&tmp_queue_wakeup))) {
>>> +        QSIMPLEQ_REMOVE_HEAD(&tmp_queue_wakeup, co_queue_next);
>>>          qemu_coroutine_enter(next);
>>>      }
>>>  }
>> What happens if co remains alive and qemu_coroutine_enter(next) causes
>> additional coroutines to add themselves to co->co_queue_wakeup?
>
> Wouldn't that happen only if co is entered again?  Then it will also
> reenter qemu_co_queue_run_restart, which may cause a different wakeup
> order but not any missing wakeups.

Exactly, that what I tried to show with stupid arrows in another mail.
I am not sure that I've succeeded :)

--
Roman