Currently check_hung_task() prints a warning if it detects the
problem, but it is not convenient to watch the system logs if
user-space wants to be notified about the hang.
Add the new trace_sched_process_hang() into check_hung_task(),
this way a user-space monitor can easily wait for the hang and
potentially resolve a problem.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
include/trace/events/sched.h | 19 +++++++++++++++++++
kernel/hung_task.c | 4 ++++
2 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 2e7d994..2a652d1 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -424,6 +424,25 @@ TRACE_EVENT(sched_pi_setprio,
__entry->oldprio, __entry->newprio)
);
+#ifdef CONFIG_DETECT_HUNG_TASK
+TRACE_EVENT(sched_process_hang,
+ TP_PROTO(struct task_struct *tsk),
+ TP_ARGS(tsk),
+
+ TP_STRUCT__entry(
+ __array( char, comm, TASK_COMM_LEN )
+ __field( pid_t, pid )
+ ),
+
+ TP_fast_assign(
+ memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
+ __entry->pid = tsk->pid;
+ ),
+
+ TP_printk("comm=%s pid=%d", __entry->comm, __entry->pid)
+);
+#endif /* CONFIG_DETECT_HUNG_TASK */
+
#endif /* _TRACE_SCHED_H */
/* This part must be outside protection */
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 3e97fb1..3952ab1 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -16,6 +16,7 @@
#include <linux/export.h>
#include <linux/sysctl.h>
#include <linux/utsname.h>
+#include <trace/events/sched.h>
/*
* The number of tasks checked:
@@ -92,6 +93,9 @@ static void check_hung_task(struct task_struct *t, unsigned
long timeout)
t->last_switch_count = switch_count;
return;
}
+
+ trace_sched_process_hang(t);
+
if (!sysctl_hung_task_warnings)
return;
sysctl_hung_task_warnings--;
--
1.5.5.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
