blob: 1fa281808e5a9327058a40de66ac29230f96fd30 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
Subject: rt: Introduce cpu_chill()
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 07 Mar 2012 20:51:03 +0100
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
---
include/linux/delay.h | 6 ++++++
1 file changed, 6 insertions(+)
Index: linux-stable/include/linux/delay.h
===================================================================
--- linux-stable.orig/include/linux/delay.h
+++ linux-stable/include/linux/delay.h
@@ -52,4 +52,10 @@ static inline void ssleep(unsigned int s
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) */
|
