Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched

* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched:
  sched: tweak the sched_runtime_limit tunable
  sched: skip updating rq's next_balance under null SD
  sched: fix broken SMT/MC optimizations
  sched: accounting regression since rc1
  sched: fix sysctl directory permissions
  sched: sched_clock_idle_[sleep|wakeup]_event()

6 files changed, 110 insertions, 43 deletions

diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index debd7dbb415..a39280b4dd3 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -292,7 +292,6 @@ static struct clocksource clocksource_tsc = {
 
 void mark_tsc_unstable(char *reason)
 {
-	sched_clock_unstable_event();
 	if (!tsc_unstable) {
 		tsc_unstable = 1;
 		tsc_enabled = 0;
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index a8634a0655f..d9b8af763e1 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -63,6 +63,7 @@
 ACPI_MODULE_NAME("processor_idle");
 #define ACPI_PROCESSOR_FILE_POWER	"power"
 #define US_TO_PM_TIMER_TICKS(t)		((t * (PM_TIMER_FREQUENCY/1000)) / 1000)
+#define PM_TIMER_TICK_NS		(1000000000ULL/PM_TIMER_FREQUENCY)
 #define C2_OVERHEAD			4	/* 1us (3.579 ticks per us) */
 #define C3_OVERHEAD			4	/* 1us (3.579 ticks per us) */
 static void (*pm_idle_save) (void) __read_mostly;
@@ -462,6 +463,9 @@ static void acpi_processor_idle(void)
 		 * TBD: Can't get time duration while in C1, as resumes
 		 *      go to an ISR rather than here.  Need to instrument
 		 *      base interrupt handler.
+		 *
+		 * Note: the TSC better not stop in C1, sched_clock() will
+		 *       skew otherwise.
 		 */
 		sleep_ticks = 0xFFFFFFFF;
 		break;
@@ -469,6 +473,8 @@ static void acpi_processor_idle(void)
 	case ACPI_STATE_C2:
 		/* Get start time (ticks) */
 		t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
+		/* Tell the scheduler that we are going deep-idle: */
+		sched_clock_idle_sleep_event();
 		/* Invoke C2 */
 		acpi_state_timer_broadcast(pr, cx, 1);
 		acpi_cstate_enter(cx);
@@ -479,17 +485,22 @@ static void acpi_processor_idle(void)
 		/* TSC halts in C2, so notify users */
 		mark_tsc_unstable("possible TSC halt in C2");
 #endif
+		/* Compute time (ticks) that we were actually asleep */
+		sleep_ticks = ticks_elapsed(t1, t2);
+
+		/* Tell the scheduler how much we idled: */
+		sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
 		/* Re-enable interrupts */
 		local_irq_enable();
+		/* Do not account our idle-switching overhead: */
+		sleep_ticks -= cx->latency_ticks + C2_OVERHEAD;
+
 		current_thread_info()->status |= TS_POLLING;
-		/* Compute time (ticks) that we were actually asleep */
-		sleep_ticks =
-		    ticks_elapsed(t1, t2) - cx->latency_ticks - C2_OVERHEAD;
 		acpi_state_timer_broadcast(pr, cx, 0);
 		break;
 
 	case ACPI_STATE_C3:
-
 		/*
 		 * disable bus master
 		 * bm_check implies we need ARB_DIS
@@ -518,6 +529,8 @@ static void acpi_processor_idle(void)
 		t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 		/* Invoke C3 */
 		acpi_state_timer_broadcast(pr, cx, 1);
+		/* Tell the scheduler that we are going deep-idle: */
+		sched_clock_idle_sleep_event();
 		acpi_cstate_enter(cx);
 		/* Get end time (ticks) */
 		t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
@@ -531,12 +544,17 @@ static void acpi_processor_idle(void)
 		/* TSC halts in C3, so notify users */
 		mark_tsc_unstable("TSC halts in C3");
 #endif
+		/* Compute time (ticks) that we were actually asleep */
+		sleep_ticks = ticks_elapsed(t1, t2);
+		/* Tell the scheduler how much we idled: */
+		sched_clock_idle_wakeup_event(sleep_ticks*PM_TIMER_TICK_NS);
+
 		/* Re-enable interrupts */
 		local_irq_enable();
+		/* Do not account our idle-switching overhead: */
+		sleep_ticks -= cx->latency_ticks + C3_OVERHEAD;
+
 		current_thread_info()->status |= TS_POLLING;
-		/* Compute time (ticks) that we were actually asleep */
-		sleep_ticks =
-		    ticks_elapsed(t1, t2) - cx->latency_ticks - C3_OVERHEAD;
 		acpi_state_timer_broadcast(pr, cx, 0);
 		break;
 
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 965625a0977..ee4814dd98f 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -320,7 +320,21 @@ int proc_pid_status(struct task_struct *task, char *buffer)
 	return buffer - orig;
 }
 
-static clock_t task_utime(struct task_struct *p)
+/*
+ * Use precise platform statistics if available:
+ */
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+static cputime_t task_utime(struct task_struct *p)
+{
+	return p->utime;
+}
+
+static cputime_t task_stime(struct task_struct *p)
+{
+	return p->stime;
+}
+#else
+static cputime_t task_utime(struct task_struct *p)
 {
 	clock_t utime = cputime_to_clock_t(p->utime),
 		total = utime + cputime_to_clock_t(p->stime);
@@ -337,10 +351,10 @@ static clock_t task_utime(struct task_struct *p)
 	}
 	utime = (clock_t)temp;
 
-	return utime;
+	return clock_t_to_cputime(utime);
 }
 
-static clock_t task_stime(struct task_struct *p)
+static cputime_t task_stime(struct task_struct *p)
 {
 	clock_t stime;
 
@@ -349,10 +363,12 @@ static clock_t task_stime(struct task_struct *p)
 	 * the total, to make sure the total observed by userspace
 	 * grows monotonically - apps rely on that):
 	 */
-	stime = nsec_to_clock_t(p->se.sum_exec_runtime) - task_utime(p);
+	stime = nsec_to_clock_t(p->se.sum_exec_runtime) -
+			cputime_to_clock_t(task_utime(p));
 
-	return stime;
+	return clock_t_to_cputime(stime);
 }
+#endif
 
 static int do_task_stat(struct task_struct *task, char *buffer, int whole)
 {
@@ -368,8 +384,7 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
 	unsigned long long start_time;
 	unsigned long cmin_flt = 0, cmaj_flt = 0;
 	unsigned long  min_flt = 0,  maj_flt = 0;
-	cputime_t cutime, cstime;
-	clock_t utime, stime;
+	cputime_t cutime, cstime, utime, stime;
 	unsigned long rsslim = 0;
 	char tcomm[sizeof(task->comm)];
 	unsigned long flags;
@@ -387,8 +402,7 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
 
 	sigemptyset(&sigign);
 	sigemptyset(&sigcatch);
-	cutime = cstime = cputime_zero;
-	utime = stime = 0;
+	cutime = cstime = utime = stime = cputime_zero;
 
 	rcu_read_lock();
 	if (lock_task_sighand(task, &flags)) {
@@ -414,15 +428,15 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
 			do {
 				min_flt += t->min_flt;
 				maj_flt += t->maj_flt;
-				utime += task_utime(t);
-				stime += task_stime(t);
+				utime = cputime_add(utime, task_utime(t));
+				stime = cputime_add(stime, task_stime(t));
 				t = next_thread(t);
 			} while (t != task);
 
 			min_flt += sig->min_flt;
 			maj_flt += sig->maj_flt;
-			utime += cputime_to_clock_t(sig->utime);
-			stime += cputime_to_clock_t(sig->stime);
+			utime = cputime_add(utime, sig->utime);
+			stime = cputime_add(stime, sig->stime);
 		}
 
 		sid = signal_session(sig);
@@ -471,8 +485,8 @@ static int do_task_stat(struct task_struct *task, char *buffer, int whole)
 		cmin_flt,
 		maj_flt,
 		cmaj_flt,
-		utime,
-		stime,
+		cputime_to_clock_t(utime),
+		cputime_to_clock_t(stime),
 		cputime_to_clock_t(cutime),
 		cputime_to_clock_t(cstime),
 		priority,
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 682ef87da6e..ba78807eab9 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -681,7 +681,7 @@ enum cpu_idle_type {
 #define SCHED_LOAD_SHIFT	10
 #define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)
 
-#define SCHED_LOAD_SCALE_FUZZ	(SCHED_LOAD_SCALE >> 1)
+#define SCHED_LOAD_SCALE_FUZZ	SCHED_LOAD_SCALE
 
 #ifdef CONFIG_SMP
 #define SD_LOAD_BALANCE		1	/* Do load balancing on this domain. */
@@ -1388,7 +1388,8 @@ extern void sched_exec(void);
 #define sched_exec()   {}
 #endif
 
-extern void sched_clock_unstable_event(void);
+extern void sched_clock_idle_sleep_event(void);
+extern void sched_clock_idle_wakeup_event(u64 delta_ns);
 
 #ifdef CONFIG_HOTPLUG_CPU
 extern void idle_task_exit(void);
diff --git a/kernel/sched.c b/kernel/sched.c
index 45e17b83b7f..96e9b82246d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -262,7 +262,8 @@ struct rq {
 	s64 clock_max_delta;
 
 	unsigned int clock_warps, clock_overflows;
-	unsigned int clock_unstable_events;
+	u64 idle_clock;
+	unsigned int clock_deep_idle_events;
 	u64 tick_timestamp;
 
 	atomic_t nr_iowait;
@@ -556,18 +557,40 @@ static inline struct rq *this_rq_lock(void)
 }
 
 /*
- * CPU frequency is/was unstable - start new by setting prev_clock_raw:
+ * We are going deep-idle (irqs are disabled):
  */
-void sched_clock_unstable_event(void)
+void sched_clock_idle_sleep_event(void)
 {
-	unsigned long flags;
-	struct rq *rq;
+	struct rq *rq = cpu_rq(smp_processor_id());
 
-	rq = task_rq_lock(current, &flags);
-	rq->prev_clock_raw = sched_clock();
-	rq->clock_unstable_events++;
-	task_rq_unlock(rq, &flags);
+	spin_lock(&rq->lock);
+	__update_rq_clock(rq);
+	spin_unlock(&rq->lock);
+	rq->clock_deep_idle_events++;
 }
+EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
+
+/*
+ * We just idled delta nanoseconds (called with irqs disabled):
+ */
+void sched_clock_idle_wakeup_event(u64 delta_ns)
+{
+	struct rq *rq = cpu_rq(smp_processor_id());
+	u64 now = sched_clock();
+
+	rq->idle_clock += delta_ns;
+	/*
+	 * Override the previous timestamp and ignore all
+	 * sched_clock() deltas that occured while we idled,
+	 * and use the PM-provided delta_ns to advance the
+	 * rq clock:
+	 */
+	spin_lock(&rq->lock);
+	rq->prev_clock_raw = now;
+	rq->clock += delta_ns;
+	spin_unlock(&rq->lock);
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
 
 /*
  * resched_task - mark a task 'to be rescheduled now'.
@@ -2494,7 +2517,7 @@ group_next:
 	 * a think about bumping its value to force at least one task to be
 	 * moved
 	 */
-	if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) {
+	if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task) {
 		unsigned long tmp, pwr_now, pwr_move;
 		unsigned int imbn;
 
@@ -3020,6 +3043,7 @@ static inline void rebalance_domains(int cpu, enum cpu_idle_type idle)
 	struct sched_domain *sd;
 	/* Earliest time when we have to do rebalance again */
 	unsigned long next_balance = jiffies + 60*HZ;
+	int update_next_balance = 0;
 
 	for_each_domain(cpu, sd) {
 		if (!(sd->flags & SD_LOAD_BALANCE))
@@ -3056,8 +3080,10 @@ static inline void rebalance_domains(int cpu, enum cpu_idle_type idle)
 		if (sd->flags & SD_SERIALIZE)
 			spin_unlock(&balancing);
 out:
-		if (time_after(next_balance, sd->last_balance + interval))
+		if (time_after(next_balance, sd->last_balance + interval)) {
 			next_balance = sd->last_balance + interval;
+			update_next_balance = 1;
+		}
 
 		/*
 		 * Stop the load balance at this level. There is another
@@ -3067,7 +3093,14 @@ out:
 		if (!balance)
 			break;
 	}
-	rq->next_balance = next_balance;
+
+	/*
+	 * next_balance will be updated only when there is a need.
+	 * When the cpu is attached to null domain for ex, it will not be
+	 * updated.
+	 */
+	if (likely(update_next_balance))
+		rq->next_balance = next_balance;
 }
 
 /*
@@ -4890,7 +4923,7 @@ static inline void sched_init_granularity(void)
 	if (sysctl_sched_granularity > gran_limit)
 		sysctl_sched_granularity = gran_limit;
 
-	sysctl_sched_runtime_limit = sysctl_sched_granularity * 4;
+	sysctl_sched_runtime_limit = sysctl_sched_granularity * 8;
 	sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2;
 }
 
@@ -5234,15 +5267,16 @@ static void migrate_dead_tasks(unsigned int dead_cpu)
 static struct ctl_table sd_ctl_dir[] = {
 	{
 		.procname	= "sched_domain",
-		.mode		= 0755,
+		.mode		= 0555,
 	},
 	{0,},
 };
 
 static struct ctl_table sd_ctl_root[] = {
 	{
+		.ctl_name	= CTL_KERN,
 		.procname	= "kernel",
-		.mode		= 0755,
+		.mode		= 0555,
 		.child		= sd_ctl_dir,
 	},
 	{0,},
@@ -5318,7 +5352,7 @@ static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
 	for_each_domain(cpu, sd) {
 		snprintf(buf, 32, "domain%d", i);
 		entry->procname = kstrdup(buf, GFP_KERNEL);
-		entry->mode = 0755;
+		entry->mode = 0555;
 		entry->child = sd_alloc_ctl_domain_table(sd);
 		entry++;
 		i++;
@@ -5338,7 +5372,7 @@ static void init_sched_domain_sysctl(void)
 	for (i = 0; i < cpu_num; i++, entry++) {
 		snprintf(buf, 32, "cpu%d", i);
 		entry->procname = kstrdup(buf, GFP_KERNEL);
-		entry->mode = 0755;
+		entry->mode = 0555;
 		entry->child = sd_alloc_ctl_cpu_table(i);
 	}
 	sd_sysctl_header = register_sysctl_table(sd_ctl_root);
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 87e524762b8..ab18f45f2ab 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -154,10 +154,11 @@ static void print_cpu(struct seq_file *m, int cpu)
 	P(next_balance);
 	P(curr->pid);
 	P(clock);
+	P(idle_clock);
 	P(prev_clock_raw);
 	P(clock_warps);
 	P(clock_overflows);
-	P(clock_unstable_events);
+	P(clock_deep_idle_events);
 	P(clock_max_delta);
 	P(cpu_load[0]);
 	P(cpu_load[1]);