clockevents: broadcast fixup possible waiters
Until the C1E patches arrived there where no users of periodic broadcast before switching to oneshot mode. Now we need to trigger a possible waiter for a periodic broadcast when switching to oneshot mode. Otherwise we can starve them for ever. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -491,6 +491,18 @@ static void tick_broadcast_clear_oneshot(int cpu)
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cpu_clear(cpu, tick_broadcast_oneshot_mask);
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}
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static void tick_broadcast_init_next_event(cpumask_t *mask, ktime_t expires)
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{
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struct tick_device *td;
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int cpu;
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for_each_cpu_mask_nr(cpu, *mask) {
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td = &per_cpu(tick_cpu_device, cpu);
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if (td->evtdev)
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td->evtdev->next_event = expires;
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}
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}
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/**
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* tick_broadcast_setup_oneshot - setup the broadcast device
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*/
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@ -498,9 +510,32 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
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{
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/* Set it up only once ! */
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if (bc->event_handler != tick_handle_oneshot_broadcast) {
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int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
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int cpu = smp_processor_id();
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cpumask_t mask;
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bc->event_handler = tick_handle_oneshot_broadcast;
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clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
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bc->next_event.tv64 = KTIME_MAX;
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/* Take the do_timer update */
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tick_do_timer_cpu = cpu;
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/*
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* We must be careful here. There might be other CPUs
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* waiting for periodic broadcast. We need to set the
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* oneshot_mask bits for those and program the
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* broadcast device to fire.
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*/
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mask = tick_broadcast_mask;
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cpu_clear(cpu, mask);
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cpus_or(tick_broadcast_oneshot_mask,
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tick_broadcast_oneshot_mask, mask);
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if (was_periodic && !cpus_empty(mask)) {
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tick_broadcast_init_next_event(&mask, tick_next_period);
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tick_broadcast_set_event(tick_next_period, 1);
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} else
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bc->next_event.tv64 = KTIME_MAX;
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}
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}
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