31 lines
958 B
Diff
31 lines
958 B
Diff
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Subject: rt: Introduce cpu_chill()
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From: Thomas Gleixner <tglx@linutronix.de>
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Date: Wed, 07 Mar 2012 20:51:03 +0100
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Retry loops on RT might loop forever when the modifying side was
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preempted. Add cpu_chill() to replace cpu_relax(). cpu_chill()
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defaults to cpu_relax() for non RT. On RT it puts the looping task to
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sleep for a tick so the preempted task can make progress.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: stable-rt@vger.kernel.org
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---
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include/linux/delay.h | 6 ++++++
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1 file changed, 6 insertions(+)
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Index: linux-3.2/include/linux/delay.h
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===================================================================
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--- linux-3.2.orig/include/linux/delay.h
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+++ linux-3.2/include/linux/delay.h
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@@ -52,4 +52,10 @@ static inline void ssleep(unsigned int s
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msleep(seconds * 1000);
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}
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+# define cpu_chill() msleep(1)
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+#else
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+# define cpu_chill() cpu_relax()
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+#endif
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+
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#endif /* defined(_LINUX_DELAY_H) */
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