softlockup: Fix hung_task_check_count sysctl

I'm seeing spikes of up to 0.5ms in khungtaskd on a large machine. To reduce this source of jitter I tried setting hung_task_check_count to 0: # echo 0 > /proc/sys/kernel/hung_task_check_count which didn't have the intended response. Change to a post increment of max_count, so a value of 0 means check 0 tasks. Signed-off-by: Anton Blanchard <[email protected]> Acked-by: Frederic Weisbecker <[email protected]> Cc: [email protected] LKML-Reference: <20091127022820.GU32182@kryten> Signed-off-by: Ingo Molnar <[email protected]>
jimmycarry · Nov 27, 2009 · e5af022 · e5af022
1 parent a8a8a66
commit e5af022
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
@@ -144,7 +144,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 
 	rcu_read_lock();
 	do_each_thread(g, t) {
-		if (!--max_count)
+		if (!max_count--)
 			goto unlock;
 		if (!--batch_count) {
 			batch_count = HUNG_TASK_BATCHING;