itimers: Add tracepoints for itimer

Add tracepoints for all itimer variants: ITIMER_REAL, ITIMER_VIRTUAL
and ITIMER_PROF.

[ tglx: Fixed comments and made the output more readable, parseable
  	and consistent. Replaced pid_vnr by pid_nr because the hrtimer
  	callback can happen in any namespace ]

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Zhaolei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A7F8B6E.2010109@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 11 insertions, 1 deletions

diff --git a/kernel/itimer.c b/kernel/itimer.c
index 8078a32d3b10..b03451ede528 100644
--- a/kernel/itimer.c
+++ b/kernel/itimer.c
@@ -12,6 +12,7 @@
 #include <linux/time.h>
 #include <linux/posix-timers.h>
 #include <linux/hrtimer.h>
+#include <trace/events/timer.h>
 
 #include <asm/uaccess.h>
 
@@ -122,6 +123,7 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer)
         struct signal_struct *sig =
                 container_of(timer, struct signal_struct, real_timer);
 
+        trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
         kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
 
         return HRTIMER_NORESTART;
@@ -166,6 +168,8 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
         }
         it->expires = nval;
         it->incr = ninterval;
+        trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
+                           ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
 
         spin_unlock_irq(&tsk->sighand->siglock);
 
@@ -217,6 +221,7 @@ again:
                 } else
                         tsk->signal->it_real_incr.tv64 = 0;
 
+                trace_itimer_state(ITIMER_REAL, value, 0);
                 spin_unlock_irq(&tsk->sighand->siglock);
                 break;
         case ITIMER_VIRTUAL:
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 12161f74744e..5c9dc228747b 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -8,6 +8,7 @@
 #include <linux/math64.h>
 #include <asm/uaccess.h>
 #include <linux/kernel_stat.h>
+#include <trace/events/timer.h>
 
 /*
  * Called after updating RLIMIT_CPU to set timer expiration if necessary.
@@ -1090,9 +1091,13 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
                                                           cputime_one_jiffy);
                                 it->error -= onecputick;
                         }
-                } else
+                } else {
                         it->expires = cputime_zero;
+                }
 
+                trace_itimer_expire(signo == SIGPROF ?
+                                    ITIMER_PROF : ITIMER_VIRTUAL,
+                                    tsk->signal->leader_pid, cur_time);
                 __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
         }