hung_task: Display every hung task warning

When khungtaskd detects hung tasks, it prints out
backtraces from a number of those tasks.

Limiting the number of backtraces being printed
out can result in the user not seeing the information
necessary to debug the issue. The hung_task_warnings
sysctl controls this feature.

This patch makes it possible for hung_task_warnings
to accept a special value to print an unlimited
number of backtraces when khungtaskd detects hung
tasks.

The special value is -1. To use this value it is
necessary to change types from ulong to int.

Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1390239253-24030-3-git-send-email-atomlin@redhat.com
[ Build warning fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Aaron Tomlin 2014-01-20 17:34:13 +00:00 committed by Ingo Molnar
parent 2397efb1bb
commit 270750dbc1
4 changed files with 52 additions and 6 deletions

View file

@ -37,7 +37,7 @@ int __read_mostly sysctl_hung_task_check_count = PID_MAX_LIMIT;
*/
unsigned long __read_mostly sysctl_hung_task_timeout_secs = CONFIG_DEFAULT_HUNG_TASK_TIMEOUT;
unsigned long __read_mostly sysctl_hung_task_warnings = 10;
int __read_mostly sysctl_hung_task_warnings = 10;
static int __read_mostly did_panic;
@ -98,7 +98,9 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
if (!sysctl_hung_task_warnings)
return;
sysctl_hung_task_warnings--;
if (sysctl_hung_task_warnings > 0)
sysctl_hung_task_warnings--;
/*
* Ok, the task did not get scheduled for more than 2 minutes,