Il 29/07/2013 05:16, Liu Ping Fan ha scritto:
> After disabling the QemuClock, we should make sure that no QemuTimers
> are still in flight. To implement that, the caller of disabling will
> wait until the last user's exit.
>
> Note, the callers of qemu_clock_enable() should be sync by themselves,
> not protected by this patch.
>
> Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
This is an interesting approach.
> - if (!clock->enabled)
> - return;
> + atomic_inc(&clock->using);
> + if (unlikely(!clock->enabled)) {
> + goto exit;
> + }
This can return directly, it doesn't need to increment and decrement
clock->using.
Paolo
>
> current_time = qemu_get_clock_ns(clock);
> tlist = clock_to_timerlist(clock);
> @@ -461,6 +482,15 @@ void qemu_run_timers(QEMUClock *clock)
> /* run the callback (the timer list can be modified) */
> ts->cb(ts->opaque);
> }
> +
> +exit:
> + qemu_mutex_lock(&clock->lock);
> + if (atomic_fetch_dec(&clock->using) == 1) {
> + if (unlikely(!clock->enabled)) {
> + qemu_cond_signal(&clock->wait_using);
> + }
> + }
> + qemu_mutex_unlock(&clock->lock);
> }
>
> int64_t qemu_get_clock_ns(QEMUClock *clock)
>
