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authorOleg Nesterov <oleg@redhat.com>2013-10-19 18:18:28 +0200
committerIngo Molnar <mingo@kernel.org>2013-10-31 11:16:18 +0100
commit6a716c90a51338009c3bc1f460829afaed8f922d (patch)
tree85e821a30e0f9350a2b67ff94d758632eec92689
parent4c4e4f61368164f326fe59e2156c70d7faa72c17 (diff)
downloadlinux-6a716c90a51338009c3bc1f460829afaed8f922d.tar.bz2
hung_task debugging: Add tracepoint to report the hang
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 <oleg@redhat.com> Cc: Dave Sullivan <dsulliva@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20131019161828.GA7439@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--include/trace/events/sched.h19
-rw-r--r--kernel/hung_task.c4
2 files changed, 23 insertions, 0 deletions
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 2e7d9947a10d..2a652d124fbb 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 042252383fd2..8807061ca004 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--;