mirror of https://github.com/xemu-project/xemu.git
aio: warn about iohandler_ctx special casing
The main loop has two AioContexts: qemu_aio_context and iohandler_ctx. The main loop runs them both, but nested aio_poll() calls on qemu_aio_context exclude iohandler_ctx. Which one should qemu_get_current_aio_context() return when called from the main loop? Document that it's always qemu_aio_context. This has subtle effects on functions that use qemu_get_current_aio_context(). For example, aio_co_reschedule_self() does not work when moving from iohandler_ctx to qemu_aio_context because qemu_get_current_aio_context() does not differentiate these two AioContexts. Document this in order to reduce the chance of future bugs. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-ID: <20240506190622.56095-3-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
parent
719c6819ed
commit
e669e800fc
|
@ -629,6 +629,9 @@ void aio_co_schedule(AioContext *ctx, Coroutine *co);
|
|||
*
|
||||
* Move the currently running coroutine to new_ctx. If the coroutine is already
|
||||
* running in new_ctx, do nothing.
|
||||
*
|
||||
* Note that this function cannot reschedule from iohandler_ctx to
|
||||
* qemu_aio_context.
|
||||
*/
|
||||
void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx);
|
||||
|
||||
|
@ -661,6 +664,9 @@ void aio_co_enter(AioContext *ctx, Coroutine *co);
|
|||
* If called from an IOThread this will be the IOThread's AioContext. If
|
||||
* called from the main thread or with the "big QEMU lock" taken it
|
||||
* will be the main loop AioContext.
|
||||
*
|
||||
* Note that the return value is never the main loop's iohandler_ctx and the
|
||||
* return value is the main loop AioContext instead.
|
||||
*/
|
||||
AioContext *qemu_get_current_aio_context(void);
|
||||
|
||||
|
|
Loading…
Reference in New Issue