summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorThomas Gleixner <tglx@linutronix.de>2012-03-07 20:51:03 +0100
committerClark Williams <williams@redhat.com>2012-03-24 10:27:28 -0500
commit2f158ed22a64bc464a5ebd3951be30ca58d82de0 (patch)
tree4ce8c3485a63df33babb41e253d5856d5a665e55
parent6412b21cf6139ceeea2b2e8fce7daf727ce1ec52 (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
-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) */