Messages in this thread Patch in this message | | | Date | Fri, 27 Nov 2009 13:28:20 +1100 | From | Anton Blanchard <> | Subject | PATCH: softlockup: Fix hung_task_check_count sysctl |
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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 <anton@samba.org> ---
Index: linux.trees.git/kernel/hung_task.c =================================================================== --- linux.trees.git.orig/kernel/hung_task.c 2009-11-27 13:11:46.000000000 +1100 +++ linux.trees.git/kernel/hung_task.c 2009-11-27 13:11:57.000000000 +1100 @@ -144,7 +144,7 @@ static void check_hung_uninterruptible_t rcu_read_lock(); do_each_thread(g, t) { - if (!--max_count) + if (!max_count--) goto unlock; if (!--batch_count) { batch_count = HUNG_TASK_BATCHING;
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