On 28/11/2017 18:09, Jeff Cody wrote:
>> Yes, terminating a scheduled coroutine is a bug; same for scheduling a
>> terminated coroutine, both orders are wrong. However, "unscheduling" is
>> not the solution; you would just be papering over the issue.
>
> Maybe we should at least add an abort on coroutine termination if there are
> still outstanding schedules, as that is preferable to operating in the
> weeds.
Sure, why not. I'm all for adding more assertions (not less :)).
>> aio_co_schedule() on a running coroutine can only happen when the
>> coroutine is going to yield soon.
>>
> That is a bit vague. What is "soon", and how does an external caller know
> if a coroutine is going to yield in this timeframe?
Soon really means "eventually"; basically if you do
f();
qemu_coroutine_yield();
then f() can call aio_co_wake() or aio_co_schedule() and knows that it
will be entirely thread-safe.
However, remember that only one aio_co_schedule() can be pending at a
single time; so if you have
f();
g();
qemu_coroutine_yield();
either f() or g() can wake you up but not both.
Thanks,
Paolo
