Messages in this thread Patch in this message | | | Date | Wed, 02 Jul 2014 13:14:16 -0400 | From | Steven Rostedt <> | Subject | [PATCH RT 2/4] timer: do not spin_trylock() on UP |
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3.12.22-rt35-rc1 stable review patch. If anyone has any objections, please let me know.
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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 611a5973d9e1..3b79da2f9c67 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
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