Merge commit 'v2.6.30-rc1' into sched/urgent

Merge reason: update to latest upstream to queue up fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 117 insertions, 9 deletions

diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 4318c30..6f7b869 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -230,6 +230,71 @@ static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
 	return 0;
 }
 
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
+{
+	struct sighand_struct *sighand;
+	struct signal_struct *sig;
+	struct task_struct *t;
+
+	*times = INIT_CPUTIME;
+
+	rcu_read_lock();
+	sighand = rcu_dereference(tsk->sighand);
+	if (!sighand)
+		goto out;
+
+	sig = tsk->signal;
+
+	t = tsk;
+	do {
+		times->utime = cputime_add(times->utime, t->utime);
+		times->stime = cputime_add(times->stime, t->stime);
+		times->sum_exec_runtime += t->se.sum_exec_runtime;
+
+		t = next_thread(t);
+	} while (t != tsk);
+
+	times->utime = cputime_add(times->utime, sig->utime);
+	times->stime = cputime_add(times->stime, sig->stime);
+	times->sum_exec_runtime += sig->sum_sched_runtime;
+out:
+	rcu_read_unlock();
+}
+
+static void update_gt_cputime(struct task_cputime *a, struct task_cputime *b)
+{
+	if (cputime_gt(b->utime, a->utime))
+		a->utime = b->utime;
+
+	if (cputime_gt(b->stime, a->stime))
+		a->stime = b->stime;
+
+	if (b->sum_exec_runtime > a->sum_exec_runtime)
+		a->sum_exec_runtime = b->sum_exec_runtime;
+}
+
+void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
+{
+	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+	struct task_cputime sum;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cputimer->lock, flags);
+	if (!cputimer->running) {
+		cputimer->running = 1;
+		/*
+		 * The POSIX timer interface allows for absolute time expiry
+		 * values through the TIMER_ABSTIME flag, therefore we have
+		 * to synchronize the timer to the clock every time we start
+		 * it.
+		 */
+		thread_group_cputime(tsk, &sum);
+		update_gt_cputime(&cputimer->cputime, &sum);
+	}
+	*times = cputimer->cputime;
+	spin_unlock_irqrestore(&cputimer->lock, flags);
+}
+
 /*
  * Sample a process (thread group) clock for the given group_leader task.
  * Must be called with tasklist_lock held for reading.
@@ -458,7 +523,7 @@ 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);
 }
@@ -617,6 +682,33 @@ static void cpu_timer_fire(struct k_itimer *timer)
 }
 
 /*
+ * Sample a process (thread group) timer for the given group_leader task.
+ * Must be called with tasklist_lock held for reading.
+ */
+static int cpu_timer_sample_group(const clockid_t which_clock,
+				  struct task_struct *p,
+				  union cpu_time_count *cpu)
+{
+	struct task_cputime cputime;
+
+	thread_group_cputimer(p, &cputime);
+	switch (CPUCLOCK_WHICH(which_clock)) {
+	default:
+		return -EINVAL;
+	case CPUCLOCK_PROF:
+		cpu->cpu = cputime_add(cputime.utime, cputime.stime);
+		break;
+	case CPUCLOCK_VIRT:
+		cpu->cpu = cputime.utime;
+		break;
+	case CPUCLOCK_SCHED:
+		cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
+		break;
+	}
+	return 0;
+}
+
+/*
  * Guts of sys_timer_settime for CPU timers.
  * This is called with the timer locked and interrupts disabled.
  * If we return TIMER_RETRY, it's necessary to release the timer's lock
@@ -677,7 +769,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags,
 	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
 		cpu_clock_sample(timer->it_clock, p, &val);
 	} else {
-		cpu_clock_sample_group(timer->it_clock, p, &val);
+		cpu_timer_sample_group(timer->it_clock, p, &val);
 	}
 
 	if (old) {
@@ -825,7 +917,7 @@ void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
 			read_unlock(&tasklist_lock);
 			goto dead;
 		} else {
-			cpu_clock_sample_group(timer->it_clock, p, &now);
+			cpu_timer_sample_group(timer->it_clock, p, &now);
 			clear_dead = (unlikely(p->exit_state) &&
 				      thread_group_empty(p));
 		}
@@ -965,6 +1057,19 @@ 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
@@ -988,13 +1093,15 @@ static void check_process_timers(struct task_struct *tsk,
 	    sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
 	    list_empty(&timers[CPUCLOCK_VIRT]) &&
 	    cputime_eq(sig->it_virt_expires, cputime_zero) &&
-	    list_empty(&timers[CPUCLOCK_SCHED]))
+	    list_empty(&timers[CPUCLOCK_SCHED])) {
+		stop_process_timers(tsk);
 		return;
+	}
 
 	/*
 	 * Collect the current process totals.
 	 */
-	thread_group_cputime(tsk, &cputime);
+	thread_group_cputimer(tsk, &cputime);
 	utime = cputime.utime;
 	ptime = cputime_add(utime, cputime.stime);
 	sum_sched_runtime = cputime.sum_exec_runtime;
@@ -1165,7 +1272,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer)
 			clear_dead_task(timer, now);
 			goto out_unlock;
 		}
-		cpu_clock_sample_group(timer->it_clock, p, &now);
+		cpu_timer_sample_group(timer->it_clock, p, &now);
 		bump_cpu_timer(timer, now);
 		/* Leave the tasklist_lock locked for the call below.  */
 	}
@@ -1260,11 +1367,12 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 	if (!task_cputime_zero(&sig->cputime_expires)) {
 		struct task_cputime group_sample;
 
-		thread_group_cputime(tsk, &group_sample);
+		thread_group_cputimer(tsk, &group_sample);
 		if (task_cputime_expired(&group_sample, &sig->cputime_expires))
 			return 1;
 	}
-	return 0;
+
+	return sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY;
 }
 
 /*
@@ -1342,7 +1450,7 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
 	struct list_head *head;
 
 	BUG_ON(clock_idx == CPUCLOCK_SCHED);
-	cpu_clock_sample_group(clock_idx, tsk, &now);
+	cpu_timer_sample_group(clock_idx, tsk, &now);
 
 	if (oldval) {
 		if (!cputime_eq(*oldval, cputime_zero)) {