On Mon, Jul 06, 2026 at 04:59:30PM +0800, Zhang Chen wrote:
> On Thu, Jul 2, 2026 at 2:39 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Wed, Jun 24, 2026 at 03:08:42PM +0800, Zhang Chen wrote:
> > > Since previous patches introduced explicit monitor tracking and reference
> > > counting via IOThreadHolder during initialization, standard global calls
> > > to iothread_get_aio_context() are no longer appropriate for raw context
> > > fetches.
> > >
> > > Switch the remaining fallback sites in monitor_suspend(), monitor_resume(),
> > > and monitor_init_qmp() to use iothread_unsafe_get_aio_context(). This aligns
> > > with the new safe ref/unref lifecycles introduced for monitor tracking.
> >
> > Why is the unsafe API used here? monitor_data_init() now takes a
> > reference and gets the AioContext. Can you use that AioContext here
> > instead of fetching it with iothread_unsafe_get_aio_context()?
> 
> Because we have some comments from this series V8 patches:
> https://lists.gnu.org/archive/html/qemu-devel/2026-06/msg00375.html
> 
> If OK, I will back to the V8 code and follow the [PATCH V9 06/17] comments,
> https://lists.gnu.org/archive/html/qemu-devel/2026-06/msg07323.html
> based on Daniel's series for monitor parts in V10.

Markus had no objection to using safe ref/unref APIs. I think he didn't
like the additional AioContext pointer that the caller needed to manage.

Using the safe APIs is important because the risk of bugs is high with
an unsafe API. If the new safe API is too inconvenient to use, then
let's find a different API design.

Here is a variation of the API that requires the caller to hold just 1
thing - the ref:

IOThreadRef *iothread_ref_get(IOThread *iothread, const IOThreadHolder *holder);
void iothread_ref_put(IOThreadRef *ref);
AioContext *iothread_ref_get_aio_context(IOThreadRef *ref);

The caller can call iothread_ref_get_aio_aio_context() multiple times,
so they no longer need to store the AioContext pointer.

Since iothread_ref_put() takes IOThreadRef, the caller doesn't need to
build a new IOThreadHolder when releasing the reference.

What do you think?

Stefan