58 lines
1.7 KiB
Diff
58 lines
1.7 KiB
Diff
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From: Ingo Molnar <mingo@elte.hu>
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Date: Fri, 3 Jul 2009 08:30:20 -0500
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Subject: timers: preempt-rt support
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.14/patches-3.14.0-rt1.tar.xz
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Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/timer.c | 15 ++++++++++++---
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1 file changed, 12 insertions(+), 3 deletions(-)
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--- a/kernel/timer.c
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+++ b/kernel/timer.c
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@@ -1358,7 +1358,17 @@ unsigned long get_next_timer_interrupt(u
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if (cpu_is_offline(smp_processor_id()))
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return expires;
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+ /*
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+ * On PREEMPT_RT we cannot sleep here. If the trylock does not
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+ * succeed then we return the worst-case 'expires in 1 tick'
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+ * value:
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+ */
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+ if (!spin_trylock(&base->lock))
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+ return now + 1;
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+#else
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spin_lock(&base->lock);
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+#endif
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if (base->active_timers) {
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if (time_before_eq(base->next_timer, base->timer_jiffies))
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base->next_timer = __next_timer_interrupt(base);
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@@ -1368,7 +1378,6 @@ unsigned long get_next_timer_interrupt(u
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if (time_before_eq(expires, now))
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return now;
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-
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return cmp_next_hrtimer_event(now, expires);
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}
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#endif
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@@ -1618,7 +1627,7 @@ static void migrate_timers(int cpu)
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BUG_ON(cpu_online(cpu));
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old_base = per_cpu(tvec_bases, cpu);
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- new_base = get_cpu_var(tvec_bases);
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+ new_base = get_local_var(tvec_bases);
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/*
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* The caller is globally serialized and nobody else
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* takes two locks at once, deadlock is not possible.
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@@ -1639,7 +1648,7 @@ static void migrate_timers(int cpu)
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spin_unlock(&old_base->lock);
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spin_unlock_irq(&new_base->lock);
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- put_cpu_var(tvec_bases);
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+ put_local_var(tvec_bases);
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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