On 29/01/2018 08:26, Stefan Hajnoczi wrote:
>> /**
>> - * Enter the next coroutine in the queue
>> + * Immediately enter the next coroutine in the queue. Release the mutex
>> + * while it runs.
>
> s/mutex/lock/
>
> Is this doc comment correct? I see multiple cases due to aio_co_wake():
>
> 1. Called from coroutine context with current AioContext matching next
> coroutine's AioContext: arrange for next coroutine to be entered
> *after* we yield (not "immediately").
>
> 2. Called from non-coroutine context with current AioContext matching
> next coroutine's AioContext: immediately enter next coroutine.
>
> 3. Called from different AioContext than next coroutine: arrange for
> next coroutine to be entered at some point.
Good point, it needs to be more specific. Here is the best I could come up
with:
+ * Removes the next coroutine from the CoQueue, and wake it up.
* Returns true if a coroutine was removed, false if the queue is empty.
*/
bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
...
+ * Empties the CoQueue; all coroutines are woken up.
*/
void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
...
+ * Removes the next coroutine from the CoQueue, and wake it up. Unlike
+ * qemu_co_queue_next, this function releases the lock during aio_co_wake
+ * because it is meant to be used outside coroutine context; in that case, the
+ * coroutine is entered immediately, before qemu_co_enter_next returns.
+ *
+ * If used in coroutine context, qemu_co_enter_next is equivalent to
+ * qemu_co_queue_next.
*/
#define qemu_co_enter_next(queue, lock) \
qemu_co_enter_next_impl(queue, QEMU_MAKE_LOCKABLE(lock))
