---

yaml
---
r: 131269
b: refs/heads/master
c: 3fccfd6
h: refs/heads/master
i:
  131267: fe6b953
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ff08f76d738d0ec0f334b187f61e160caa321d54
+refs/heads/master: 3fccfd67df79c6351a156eb25a7a514e5f39c4d9

trunk/include/linux/sched.h

@@ -2209,6 +2209,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 	unsigned long flags;
 
 	spin_lock_irqsave(&cputimer->lock, flags);
+	cputimer->running = 1;
 	*times = cputimer->cputime;
 	spin_unlock_irqrestore(&cputimer->lock, flags);
 }

trunk/kernel/posix-cpu-timers.c

@@ -488,7 +488,7 @@ void posix_cpu_timers_exit_group(struct task_struct *tsk)
 {
 	struct task_cputime cputime;
 
-	thread_group_cputime(tsk, &cputime);
+	thread_group_cputimer(tsk, &cputime);
 	cleanup_timers(tsk->signal->cpu_timers,
 		       cputime.utime, cputime.stime, cputime.sum_exec_runtime);
 }
@@ -506,29 +506,6 @@ static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
 					     now);
 }
 
-/*
- * Enable the process wide cpu timer accounting.
- *
- * serialized using ->sighand->siglock
- */
-static void start_process_timers(struct task_struct *tsk)
-{
-	tsk->signal->cputimer.running = 1;
-	barrier();
-}
-
-/*
- * Release the process wide timer accounting -- timer stops ticking when
- * nobody cares about it.
- *
- * serialized using ->sighand->siglock
- */
-static void stop_process_timers(struct task_struct *tsk)
-{
-	tsk->signal->cputimer.running = 0;
-	barrier();
-}
-
 /*
  * Insert the timer on the appropriate list before any timers that
  * expire later.  This must be called with the tasklist_lock held
@@ -549,9 +526,6 @@ static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
 	BUG_ON(!irqs_disabled());
 	spin_lock(&p->sighand->siglock);
 
-	if (!CPUCLOCK_PERTHREAD(timer->it_clock))
-		start_process_timers(p);
-
 	listpos = head;
 	if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
 		list_for_each_entry(next, head, entry) {
@@ -1021,6 +995,19 @@ static void check_thread_timers(struct task_struct *tsk,
 	}
 }
 
+static void stop_process_timers(struct task_struct *tsk)
+{
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+	unsigned long flags;
+
+	if (!cputimer->running)
+		return;
+
+	spin_lock_irqsave(&cputimer->lock, flags);
+	cputimer->running = 0;
+	spin_unlock_irqrestore(&cputimer->lock, flags);
+}
+
 /*
  * Check for any per-thread CPU timers that have fired and move them
  * off the tsk->*_timers list onto the firing list.  Per-thread timers
@@ -1427,7 +1414,6 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 	struct list_head *head;
 
 	BUG_ON(clock_idx == CPUCLOCK_SCHED);
-	start_process_timers(tsk);
 	cpu_timer_sample_group(clock_idx, tsk, &now);
 
 	if (oldval) {