[patch 03/54] NOHZ: Rate limit the local softirq pending warning output

[Chris Wright]

-stable review patch.  If anyone has any objections, please let us know.
---------------------

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

The warning in the NOHZ code, which triggers when a CPU goes idle with
softirqs pending can fill up the logs quite quickly.  Rate limit the output
until we found the root cause of that problem.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---

 kernel/time/tick-sched.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

--- linux-2.6.21.4.orig/kernel/time/tick-sched.c
+++ linux-2.6.21.4/kernel/time/tick-sched.c
@@ -167,9 +167,15 @@ void tick_nohz_stop_sched_tick(void)
 		goto end;
 
 	cpu = smp_processor_id();
-	if (unlikely(local_softirq_pending()))
-		printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
-		       local_softirq_pending());
+	if (unlikely(local_softirq_pending())) {
+		static int ratelimit;
+
+		if (ratelimit < 10) {
+			printk(KERN_ERR "NOHZ: local_softirq_pending %02x\n",
+			       local_softirq_pending());
+			ratelimit++;
+		}
+	}
 
 	now = ktime_get();
 	/*

-- 
-
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