Messages in this thread Patch in this message | | | Date | Tue, 13 Mar 2012 22:27:01 -0400 | From | Steven Rostedt <> | Subject | [PATCH RT 3/7] rt: Introduce cpu_chill() |
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From: Thomas Gleixner <tglx@linutronix.de>
Retry loops on RT might loop forever when the modifying side was preempted. Add cpu_chill() to replace cpu_relax(). cpu_chill() defaults to cpu_relax() for non RT. On RT it puts the looping task to sleep for a tick so the preempted task can make progress.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- include/linux/delay.h | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/include/linux/delay.h b/include/linux/delay.h index a6ecb34..e23a7c0 100644 --- a/include/linux/delay.h +++ b/include/linux/delay.h @@ -52,4 +52,10 @@ static inline void ssleep(unsigned int seconds) msleep(seconds * 1000); } +#ifdef CONFIG_PREEMPT_RT_FULL +# define cpu_chill() msleep(1) +#else +# define cpu_chill() cpu_relax() +#endif + #endif /* defined(_LINUX_DELAY_H) */ -- 1.7.8.3
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