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Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb |
Date: |
Mon, 29 Jul 2013 08:30:26 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 |
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 <address@hidden>
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)
>
- [Qemu-devel] [RFC v2 0/5] arm AioContext with its own timer stuff, Liu Ping Fan, 2013/07/28
- [Qemu-devel] [RFC v2 1/5] timer: protect timers_state with lock, Liu Ping Fan, 2013/07/28
- [Qemu-devel] [RFC v2 2/5] timer: pick out timer list info from QemuClock, Liu Ping Fan, 2013/07/28
- [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, Liu Ping Fan, 2013/07/28
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb,
Paolo Bonzini <=
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, liu ping fan, 2013/07/29
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, Paolo Bonzini, 2013/07/29
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, liu ping fan, 2013/07/29
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, Paolo Bonzini, 2013/07/30
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, Alex Bligh, 2013/07/30
- Re: [Qemu-devel] [RFC v2 3/5] timer: make qemu_clock_enable sync between disable and timer's cb, Paolo Bonzini, 2013/07/30
[Qemu-devel] [RFC v2 4/5] timer: associate three timerlists with AioContext, Liu Ping Fan, 2013/07/28