Re: [PATCH 3/8] qemu-thread-win32: cleanup, fix, document QemuEvent

[Paolo Bonzini]

On 3/6/23 15:32, David Hildenbrand wrote:
> > Thinking more about it, the intended usage of QemuEvent is either
> >
> >       qemu_event_reset();
> >       if (!check()) {
> >            qemu_event_wait());
> >       }
> >
> > or
> >
> >       if (!check()) {
> >           qemu_event_reset();
> >           if (!check()) {
> >                qemu_event_wait());
> >           }
> >       }
> >
> > If we don't care on the reset path we care much less on the wait path.
> > Should I remove it and go straight to the cmpxchg, just for peace of 
> > mind?
>
> Sounds reasonable to me at could simplify qemu_event_wait a bit.

Hmm, it does avoid a whole system call in the Windows case, so I prefer 
to keep it.  And I prefer to keep the load-acquire on the fast path too, 
I don't think it's needed in the actual uses of QemuEvent but it's safer 
in case it's used as "just a boolean".

Paolo