[PATCH RT 1/3] timer: do not spin_trylock() on UP
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2014-07-02 19:52:34
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Subsystem:
the rest · Maintainer:
Linus Torvalds
3.10.44-rt46-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> This will void a warning comming from the spin-lock debugging code. The lock avoiding idea is from Steven Rostedt. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/timer.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/kernel/timer.c b/kernel/timer.c
index 26cca8b924e7..40cfa14131ca 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c@@ -1461,6 +1461,19 @@ void run_local_timers(void) * the timer softirq. */ #ifdef CONFIG_PREEMPT_RT_FULL + +#ifndef CONFIG_SMP + /* + * The spin_do_trylock() later may fail as the lock may be hold before + * the interrupt arrived. The spin-lock debugging code will raise a + * warning if the try_lock fails on UP. Since this is only an + * optimization for the FULL_NO_HZ case (not to run the timer softirq on + * an nohz_full CPU) we don't really care and shedule the softirq. + */ + raise_softirq(TIMER_SOFTIRQ); + return; +#endif + /* On RT, irq work runs from softirq */ if (irq_work_needs_cpu()) { raise_softirq(TIMER_SOFTIRQ);
--
2.0.0