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authorThomas Gleixner <tglx@linutronix.de>2012-03-07 20:51:03 +0100
committerSteven Rostedt <rostedt@rostedt.homelinux.com>2013-02-25 13:33:25 -0500
commite9c907f10debbcf85f2df127aa4ff189168d7f5d (patch)
tree2af7d98c9f5498cf45c60398848da432694930f6 /include
parent7f3e62b1ba01b40a5c6245270a198a7059032f62 (diff)
rt: Introduce cpu_chill()
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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/delay.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/delay.h b/include/linux/delay.h
index a6ecb34cf547..e23a7c021eeb 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) */