On Tue, Feb 26, 2019 at 10:58 AM Tetsuo Handa <[email protected]> wrote: > > Since commit a2e514453861dd39 ("kernel/hung_task.c: allow to set checking > interval separately from timeout") added hung_task_check_interval_secs, > setting a value different from hung_task_timeout_secs > > echo 0 > /proc/sys/kernel/hung_task_panic > echo 120 > /proc/sys/kernel/hung_task_timeout_secs > echo 5 > /proc/sys/kernel/hung_task_check_interval_secs > > causes confusing output as if the task was blocked for > hung_task_timeout_secs seconds from the previous report. > > [ 399.395930] INFO: task kswapd0:75 blocked for more than 120 seconds. > [ 405.027637] INFO: task kswapd0:75 blocked for more than 120 seconds. > [ 410.659725] INFO: task kswapd0:75 blocked for more than 120 seconds. > [ 416.292860] INFO: task kswapd0:75 blocked for more than 120 seconds. > [ 421.932305] INFO: task kswapd0:75 blocked for more than 120 seconds. > > Although we could update t->last_switch_time after sched_show_task(t) if > we want to report only every 120 seconds, reporting every 5 seconds might > not be very bad for monitoring after a problematic situation has started. > Thus, let's use continuously blocked time instead of updating previously > reported time. > > [ 677.985011] INFO: task kswapd0:80 blocked for more than 122 seconds. > [ 693.856126] INFO: task kswapd0:80 blocked for more than 138 seconds. > [ 709.728075] INFO: task kswapd0:80 blocked for more than 154 seconds. > [ 725.600018] INFO: task kswapd0:80 blocked for more than 170 seconds. > [ 741.473133] INFO: task kswapd0:80 blocked for more than 186 seconds. > > Signed-off-by: Tetsuo Handa <[email protected]> > --- > 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 4a91916..6429139 100644 > --- a/kernel/hung_task.c > +++ b/kernel/hung_task.c > @@ -126,7 +126,7 @@ static void check_hung_task(struct task_struct *t, > unsigned long timeout) > if (sysctl_hung_task_warnings > 0) > sysctl_hung_task_warnings--; > pr_err("INFO: task %s:%d blocked for more than %ld > seconds.\n", > - t->comm, t->pid, timeout); > + t->comm, t->pid, (jiffies - t->last_switch_time) / HZ);
Looks like an improvement to me. Acked-by: Dmitry Vyukov <[email protected]> > pr_err(" %s %s %.*s\n", > print_tainted(), init_utsname()->release, > (int)strcspn(init_utsname()->version, " "), > -- > 1.8.3.1
