From e5af02261668350b43eb7381648930bde8e872f7 Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Fri, 27 Nov 2009 13:28:20 +1100 Subject: [PATCH] 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 Acked-by: Frederic Weisbecker Cc: msb@google.com LKML-Reference: <20091127022820.GU32182@kryten> Signed-off-by: Ingo Molnar --- kernel/hung_task.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index d4e84174740..0c642d51aac 100644 --- 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;