From 7bb67439bf6bd3782f07f1d7be1e63406453d5de Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 31 Aug 2008 08:05:58 -0700
Subject: select: Introduce a hrtimeout function

This patch adds a schedule_hrtimeout() function, to be used by select() and
poll() in a later patch. This function works similar to schedule_timeout()
in most ways, but takes a timespec rather than jiffies.

With a lot of contributions/fixes from Thomas

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/hrtimer.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index b8e4dce80a74..782137dc755f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1678,3 +1678,68 @@ void __init hrtimers_init(void)
 #endif
 }
 
+/**
+ * schedule_hrtimeout - sleep until timeout
+ * @expires:	timeout value (ktime_t)
+ * @mode:	timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns.
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired otherwise -EINTR
+ */
+int __sched schedule_hrtimeout(ktime_t *expires,
+			       const enum hrtimer_mode mode)
+{
+	struct hrtimer_sleeper t;
+
+	/*
+	 * Optimize when a zero timeout value is given. It does not
+	 * matter whether this is an absolute or a relative time.
+	 */
+	if (expires && !expires->tv64) {
+		__set_current_state(TASK_RUNNING);
+		return 0;
+	}
+
+	/*
+	 * A NULL parameter means "inifinte"
+	 */
+	if (!expires) {
+		schedule();
+		__set_current_state(TASK_RUNNING);
+		return -EINTR;
+	}
+
+	hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
+	t.timer.expires = *expires;
+
+	hrtimer_init_sleeper(&t, current);
+
+	hrtimer_start(&t.timer, t.timer.expires, mode);
+	if (!hrtimer_active(&t.timer))
+		t.task = NULL;
+
+	if (likely(t.task))
+		schedule();
+
+	hrtimer_cancel(&t.timer);
+	destroy_hrtimer_on_stack(&t.timer);
+
+	__set_current_state(TASK_RUNNING);
+
+	return !t.task ? 0 : -EINTR;
+}
+EXPORT_SYMBOL_GPL(schedule_hrtimeout);
-- 
cgit v1.2.3-58-ga151


From df0cc0539b4127bd02f64de2c335b4af1fdb3845 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 31 Aug 2008 08:09:53 -0700
Subject: select: add a timespec_add_safe() function

For the select() rework, it's important to be able to add timespec
structures in an overflow-safe manner.

This patch adds a timespec_add_safe() function for this which is similar in
operation to ktime_add_safe(), but works on a struct timespec.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 include/linux/time.h |  4 ++++
 kernel/time.c        | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+)

(limited to 'kernel')

diff --git a/include/linux/time.h b/include/linux/time.h
index e15206a7e82e..726976478480 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -38,6 +38,8 @@ struct timezone {
 #define NSEC_PER_SEC	1000000000L
 #define FSEC_PER_SEC	1000000000000000L
 
+#define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
+
 static inline int timespec_equal(const struct timespec *a,
                                  const struct timespec *b)
 {
@@ -72,6 +74,8 @@ extern unsigned long mktime(const unsigned int year, const unsigned int mon,
 			    const unsigned int min, const unsigned int sec);
 
 extern void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec);
+extern struct timespec timespec_add_safe(const struct timespec lhs,
+					 const struct timespec rhs);
 
 /*
  * sub = lhs - rhs, in normalized form
diff --git a/kernel/time.c b/kernel/time.c
index 6a08660b4fac..d63a4336fad6 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -669,3 +669,21 @@ EXPORT_SYMBOL(get_jiffies_64);
 #endif
 
 EXPORT_SYMBOL(jiffies);
+
+/*
+ * Add two timespec values and do a safety check for overflow.
+ * It's assumed that both values are valid (>= 0)
+ */
+struct timespec timespec_add_safe(const struct timespec lhs,
+				  const struct timespec rhs)
+{
+	struct timespec res;
+
+	set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec,
+				lhs.tv_nsec + rhs.tv_nsec);
+
+	if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
+		res.tv_sec = TIME_T_MAX;
+
+	return res;
+}
-- 
cgit v1.2.3-58-ga151


From cc584b213f252bf698849cf4be2377cd3ec7501a Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 1 Sep 2008 15:02:30 -0700
Subject: hrtimer: convert kernel/* to the new hrtimer apis

In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts kernel/* to these accessors.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/futex.c           |  7 +++----
 kernel/hrtimer.c         | 44 +++++++++++++++++++++++---------------------
 kernel/posix-timers.c    | 10 ++++------
 kernel/rtmutex.c         |  3 +--
 kernel/sched.c           |  7 +++----
 kernel/time/ntp.c        |  3 +--
 kernel/time/tick-sched.c | 21 ++++++++++-----------
 kernel/time/timer_list.c |  4 ++--
 8 files changed, 47 insertions(+), 52 deletions(-)

(limited to 'kernel')

diff --git a/kernel/futex.c b/kernel/futex.c
index 7d1136e97c14..4cd5b4319b04 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1299,10 +1299,9 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
 			hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
 						HRTIMER_MODE_ABS);
 			hrtimer_init_sleeper(&t, current);
-			t.timer.expires = *abs_time;
+			hrtimer_set_expires(&t.timer, *abs_time);
 
-			hrtimer_start(&t.timer, t.timer.expires,
-						HRTIMER_MODE_ABS);
+			hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
 			if (!hrtimer_active(&t.timer))
 				t.task = NULL;
 
@@ -1404,7 +1403,7 @@ static int futex_lock_pi(u32 __user *uaddr, struct rw_semaphore *fshared,
 		hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME,
 				      HRTIMER_MODE_ABS);
 		hrtimer_init_sleeper(to, current);
-		to->timer.expires = *time;
+		hrtimer_set_expires(&to->timer, *time);
 	}
 
 	q.pi_state = NULL;
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 782137dc755f..ae307feec74c 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -517,7 +517,7 @@ static void hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base)
 		if (!base->first)
 			continue;
 		timer = rb_entry(base->first, struct hrtimer, node);
-		expires = ktime_sub(timer->expires, base->offset);
+		expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
 		if (expires.tv64 < cpu_base->expires_next.tv64)
 			cpu_base->expires_next = expires;
 	}
@@ -539,10 +539,10 @@ static int hrtimer_reprogram(struct hrtimer *timer,
 			     struct hrtimer_clock_base *base)
 {
 	ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
-	ktime_t expires = ktime_sub(timer->expires, base->offset);
+	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
 	int res;
 
-	WARN_ON_ONCE(timer->expires.tv64 < 0);
+	WARN_ON_ONCE(hrtimer_get_expires_tv64(timer) < 0);
 
 	/*
 	 * When the callback is running, we do not reprogram the clock event
@@ -794,7 +794,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
 	u64 orun = 1;
 	ktime_t delta;
 
-	delta = ktime_sub(now, timer->expires);
+	delta = ktime_sub(now, hrtimer_get_expires(timer));
 
 	if (delta.tv64 < 0)
 		return 0;
@@ -806,8 +806,8 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
 		s64 incr = ktime_to_ns(interval);
 
 		orun = ktime_divns(delta, incr);
-		timer->expires = ktime_add_ns(timer->expires, incr * orun);
-		if (timer->expires.tv64 > now.tv64)
+		hrtimer_add_expires_ns(timer, incr * orun);
+		if (hrtimer_get_expires_tv64(timer) > now.tv64)
 			return orun;
 		/*
 		 * This (and the ktime_add() below) is the
@@ -815,7 +815,7 @@ u64 hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval)
 		 */
 		orun++;
 	}
-	timer->expires = ktime_add_safe(timer->expires, interval);
+	hrtimer_add_expires(timer, interval);
 
 	return orun;
 }
@@ -847,7 +847,8 @@ static void enqueue_hrtimer(struct hrtimer *timer,
 		 * We dont care about collisions. Nodes with
 		 * the same expiry time stay together.
 		 */
-		if (timer->expires.tv64 < entry->expires.tv64) {
+		if (hrtimer_get_expires_tv64(timer) <
+				hrtimer_get_expires_tv64(entry)) {
 			link = &(*link)->rb_left;
 		} else {
 			link = &(*link)->rb_right;
@@ -982,7 +983,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 #endif
 	}
 
-	timer->expires = tim;
+	hrtimer_set_expires(timer, tim);
 
 	timer_stats_hrtimer_set_start_info(timer);
 
@@ -1076,7 +1077,7 @@ ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
 	ktime_t rem;
 
 	base = lock_hrtimer_base(timer, &flags);
-	rem = ktime_sub(timer->expires, base->get_time());
+	rem = hrtimer_expires_remaining(timer);
 	unlock_hrtimer_base(timer, &flags);
 
 	return rem;
@@ -1108,7 +1109,7 @@ ktime_t hrtimer_get_next_event(void)
 				continue;
 
 			timer = rb_entry(base->first, struct hrtimer, node);
-			delta.tv64 = timer->expires.tv64;
+			delta.tv64 = hrtimer_get_expires_tv64(timer);
 			delta = ktime_sub(delta, base->get_time());
 			if (delta.tv64 < mindelta.tv64)
 				mindelta.tv64 = delta.tv64;
@@ -1308,10 +1309,10 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 
 			timer = rb_entry(node, struct hrtimer, node);
 
-			if (basenow.tv64 < timer->expires.tv64) {
+			if (basenow.tv64 < hrtimer_get_expires_tv64(timer)) {
 				ktime_t expires;
 
-				expires = ktime_sub(timer->expires,
+				expires = ktime_sub(hrtimer_get_expires(timer),
 						    base->offset);
 				if (expires.tv64 < expires_next.tv64)
 					expires_next = expires;
@@ -1414,7 +1415,8 @@ void hrtimer_run_queues(void)
 			struct hrtimer *timer;
 
 			timer = rb_entry(node, struct hrtimer, node);
-			if (base->softirq_time.tv64 <= timer->expires.tv64)
+			if (base->softirq_time.tv64 <=
+					hrtimer_get_expires_tv64(timer))
 				break;
 
 			if (timer->cb_mode == HRTIMER_CB_SOFTIRQ) {
@@ -1462,7 +1464,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 
 	do {
 		set_current_state(TASK_INTERRUPTIBLE);
-		hrtimer_start(&t->timer, t->timer.expires, mode);
+		hrtimer_start_expires(&t->timer, mode);
 		if (!hrtimer_active(&t->timer))
 			t->task = NULL;
 
@@ -1484,7 +1486,7 @@ static int update_rmtp(struct hrtimer *timer, struct timespec __user *rmtp)
 	struct timespec rmt;
 	ktime_t rem;
 
-	rem = ktime_sub(timer->expires, timer->base->get_time());
+	rem = hrtimer_expires_remaining(timer);
 	if (rem.tv64 <= 0)
 		return 0;
 	rmt = ktime_to_timespec(rem);
@@ -1503,7 +1505,7 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 
 	hrtimer_init_on_stack(&t.timer, restart->nanosleep.index,
 				HRTIMER_MODE_ABS);
-	t.timer.expires.tv64 = restart->nanosleep.expires;
+	hrtimer_set_expires_tv64(&t.timer, restart->nanosleep.expires);
 
 	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
 		goto out;
@@ -1530,7 +1532,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 	int ret = 0;
 
 	hrtimer_init_on_stack(&t.timer, clockid, mode);
-	t.timer.expires = timespec_to_ktime(*rqtp);
+	hrtimer_set_expires(&t.timer, timespec_to_ktime(*rqtp));
 	if (do_nanosleep(&t, mode))
 		goto out;
 
@@ -1550,7 +1552,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 	restart->fn = hrtimer_nanosleep_restart;
 	restart->nanosleep.index = t.timer.base->index;
 	restart->nanosleep.rmtp = rmtp;
-	restart->nanosleep.expires = t.timer.expires.tv64;
+	restart->nanosleep.expires = hrtimer_get_expires_tv64(&t.timer);
 
 	ret = -ERESTART_RESTARTBLOCK;
 out:
@@ -1724,11 +1726,11 @@ int __sched schedule_hrtimeout(ktime_t *expires,
 	}
 
 	hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
-	t.timer.expires = *expires;
+	hrtimer_set_expires(&t.timer, *expires);
 
 	hrtimer_init_sleeper(&t, current);
 
-	hrtimer_start(&t.timer, t.timer.expires, mode);
+	hrtimer_start_expires(&t.timer, mode);
 	if (!hrtimer_active(&t.timer))
 		t.task = NULL;
 
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index e36d5798cbff..f85efcdcab2d 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -668,7 +668,7 @@ common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
 	    (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
 		timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
 
-	remaining = ktime_sub(timer->expires, now);
+	remaining = ktime_sub(hrtimer_get_expires(timer), now);
 	/* Return 0 only, when the timer is expired and not pending */
 	if (remaining.tv64 <= 0) {
 		/*
@@ -762,7 +762,7 @@ common_timer_set(struct k_itimer *timr, int flags,
 	hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
 	timr->it.real.timer.function = posix_timer_fn;
 
-	timer->expires = timespec_to_ktime(new_setting->it_value);
+	hrtimer_set_expires(timer, timespec_to_ktime(new_setting->it_value));
 
 	/* Convert interval */
 	timr->it.real.interval = timespec_to_ktime(new_setting->it_interval);
@@ -771,14 +771,12 @@ common_timer_set(struct k_itimer *timr, int flags,
 	if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
 		/* Setup correct expiry time for relative timers */
 		if (mode == HRTIMER_MODE_REL) {
-			timer->expires =
-				ktime_add_safe(timer->expires,
-					       timer->base->get_time());
+			hrtimer_add_expires(timer, timer->base->get_time());
 		}
 		return 0;
 	}
 
-	hrtimer_start(timer, timer->expires, mode);
+	hrtimer_start_expires(timer, mode);
 	return 0;
 }
 
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 6522ae5b14a2..69d9cb921ffa 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -631,8 +631,7 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 
 	/* Setup the timer, when timeout != NULL */
 	if (unlikely(timeout)) {
-		hrtimer_start(&timeout->timer, timeout->timer.expires,
-			      HRTIMER_MODE_ABS);
+		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
 		if (!hrtimer_active(&timeout->timer))
 			timeout->task = NULL;
 	}
diff --git a/kernel/sched.c b/kernel/sched.c
index 1a5f73c1fcdc..e46b5afa200d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -221,9 +221,8 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
 
 		now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
 		hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
-		hrtimer_start(&rt_b->rt_period_timer,
-			      rt_b->rt_period_timer.expires,
-			      HRTIMER_MODE_ABS);
+		hrtimer_start_expires(&rt_b->rt_period_timer,
+				HRTIMER_MODE_ABS);
 	}
 	spin_unlock(&rt_b->rt_runtime_lock);
 }
@@ -1058,7 +1057,7 @@ static void hrtick_start(struct rq *rq, u64 delay)
 	struct hrtimer *timer = &rq->hrtick_timer;
 	ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
 
-	timer->expires = time;
+	hrtimer_set_expires(timer, time);
 
 	if (rq == this_rq()) {
 		hrtimer_restart(timer);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 5125ddd8196b..4c8d85421d24 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -142,8 +142,7 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
 		time_state = TIME_OOP;
 		printk(KERN_NOTICE "Clock: "
 		       "inserting leap second 23:59:60 UTC\n");
-		leap_timer.expires = ktime_add_ns(leap_timer.expires,
-						  NSEC_PER_SEC);
+		hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
 		res = HRTIMER_RESTART;
 		break;
 	case TIME_DEL:
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a87b0468568b..b33be61c0f6b 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -288,7 +288,7 @@ void tick_nohz_stop_sched_tick(int inidle)
 				goto out;
 			}
 
-			ts->idle_tick = ts->sched_timer.expires;
+			ts->idle_tick = hrtimer_get_expires(&ts->sched_timer);
 			ts->tick_stopped = 1;
 			ts->idle_jiffies = last_jiffies;
 			rcu_enter_nohz();
@@ -419,21 +419,21 @@ void tick_nohz_restart_sched_tick(void)
 	ts->tick_stopped  = 0;
 	ts->idle_exittime = now;
 	hrtimer_cancel(&ts->sched_timer);
-	ts->sched_timer.expires = ts->idle_tick;
+	hrtimer_set_expires(&ts->sched_timer, ts->idle_tick);
 
 	while (1) {
 		/* Forward the time to expire in the future */
 		hrtimer_forward(&ts->sched_timer, now, tick_period);
 
 		if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
-			hrtimer_start(&ts->sched_timer,
-				      ts->sched_timer.expires,
+			hrtimer_start_expires(&ts->sched_timer,
 				      HRTIMER_MODE_ABS);
 			/* Check, if the timer was already in the past */
 			if (hrtimer_active(&ts->sched_timer))
 				break;
 		} else {
-			if (!tick_program_event(ts->sched_timer.expires, 0))
+			if (!tick_program_event(
+				hrtimer_get_expires(&ts->sched_timer), 0))
 				break;
 		}
 		/* Update jiffies and reread time */
@@ -446,7 +446,7 @@ void tick_nohz_restart_sched_tick(void)
 static int tick_nohz_reprogram(struct tick_sched *ts, ktime_t now)
 {
 	hrtimer_forward(&ts->sched_timer, now, tick_period);
-	return tick_program_event(ts->sched_timer.expires, 0);
+	return tick_program_event(hrtimer_get_expires(&ts->sched_timer), 0);
 }
 
 /*
@@ -529,7 +529,7 @@ static void tick_nohz_switch_to_nohz(void)
 	next = tick_init_jiffy_update();
 
 	for (;;) {
-		ts->sched_timer.expires = next;
+		hrtimer_set_expires(&ts->sched_timer, next);
 		if (!tick_program_event(next, 0))
 			break;
 		next = ktime_add(next, tick_period);
@@ -625,16 +625,15 @@ void tick_setup_sched_timer(void)
 	ts->sched_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
 
 	/* Get the next period (per cpu) */
-	ts->sched_timer.expires = tick_init_jiffy_update();
+	hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
 	offset = ktime_to_ns(tick_period) >> 1;
 	do_div(offset, num_possible_cpus());
 	offset *= smp_processor_id();
-	ts->sched_timer.expires = ktime_add_ns(ts->sched_timer.expires, offset);
+	hrtimer_add_expires_ns(&ts->sched_timer, offset);
 
 	for (;;) {
 		hrtimer_forward(&ts->sched_timer, now, tick_period);
-		hrtimer_start(&ts->sched_timer, ts->sched_timer.expires,
-			      HRTIMER_MODE_ABS);
+		hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS);
 		/* Check, if the timer was already in the past */
 		if (hrtimer_active(&ts->sched_timer))
 			break;
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index a40e20fd0001..5224a3215fb7 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -66,8 +66,8 @@ print_timer(struct seq_file *m, struct hrtimer *timer, int idx, u64 now)
 #endif
 	SEQ_printf(m, "\n");
 	SEQ_printf(m, " # expires at %Lu nsecs [in %Ld nsecs]\n",
-		(unsigned long long)ktime_to_ns(timer->expires),
-		(long long)(ktime_to_ns(timer->expires) - now));
+		(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
+		(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
 }
 
 static void
-- 
cgit v1.2.3-58-ga151


From 654c8e0b1c623b156c5b92f28d914ab38c9c2c90 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 1 Sep 2008 15:47:08 -0700
Subject: hrtimer: turn hrtimers into range timers

this patch turns hrtimers into range timers; they have 2 expire points
1) the soft expire point
2) the hard expire point

the kernel will do it's regular best effort attempt to get the timer run
at the hard expire point. However, if some other time fires after the soft
expire point, the kernel now has the freedom to fire this timer at this point,
and thus grouping the events and preventing a power-expensive wakeup in the
future.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 include/linux/hrtimer.h | 31 ++++++++++++++++++++++++++-
 kernel/hrtimer.c        | 56 +++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 82 insertions(+), 5 deletions(-)

(limited to 'kernel')

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 485a634fd6e2..28259c336679 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -112,6 +112,7 @@ enum hrtimer_cb_mode {
 struct hrtimer {
 	struct rb_node			node;
 	ktime_t				_expires;
+	ktime_t				_softexpires;
 	enum hrtimer_restart		(*function)(struct hrtimer *);
 	struct hrtimer_clock_base	*base;
 	unsigned long			state;
@@ -220,20 +221,37 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer)
 static inline void hrtimer_set_expires(struct hrtimer *timer, ktime_t time)
 {
 	timer->_expires = time;
+	timer->_softexpires = time;
 }
+
+static inline void hrtimer_set_expires_range(struct hrtimer *timer, ktime_t time, ktime_t delta)
+{
+	timer->_softexpires = time;
+	timer->_expires = ktime_add_safe(time, delta);
+}
+
+static inline void hrtimer_set_expires_range_ns(struct hrtimer *timer, ktime_t time, unsigned long delta)
+{
+	timer->_softexpires = time;
+	timer->_expires = ktime_add_safe(time, ns_to_ktime(delta));
+}
+
 static inline void hrtimer_set_expires_tv64(struct hrtimer *timer, s64 tv64)
 {
 	timer->_expires.tv64 = tv64;
+	timer->_softexpires.tv64 = tv64;
 }
 
 static inline void hrtimer_add_expires(struct hrtimer *timer, ktime_t time)
 {
 	timer->_expires = ktime_add_safe(timer->_expires, time);
+	timer->_softexpires = ktime_add_safe(timer->_softexpires, time);
 }
 
 static inline void hrtimer_add_expires_ns(struct hrtimer *timer, unsigned long ns)
 {
 	timer->_expires = ktime_add_ns(timer->_expires, ns);
+	timer->_softexpires = ktime_add_ns(timer->_softexpires, ns);
 }
 
 static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
@@ -241,10 +259,19 @@ static inline ktime_t hrtimer_get_expires(const struct hrtimer *timer)
 	return timer->_expires;
 }
 
+static inline ktime_t hrtimer_get_softexpires(const struct hrtimer *timer)
+{
+	return timer->_softexpires;
+}
+
 static inline s64 hrtimer_get_expires_tv64(const struct hrtimer *timer)
 {
 	return timer->_expires.tv64;
 }
+static inline s64 hrtimer_get_softexpires_tv64(const struct hrtimer *timer)
+{
+	return timer->_softexpires.tv64;
+}
 
 static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
 {
@@ -334,7 +361,7 @@ static inline int hrtimer_start_expires(struct hrtimer *timer,
 
 static inline int hrtimer_restart(struct hrtimer *timer)
 {
-	return hrtimer_start(timer, timer->_expires, HRTIMER_MODE_ABS);
+	return hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
 }
 
 /* Query timers: */
@@ -391,6 +418,8 @@ extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
 extern void hrtimer_init_sleeper(struct hrtimer_sleeper *sl,
 				 struct task_struct *tsk);
 
+extern int schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
+						const enum hrtimer_mode mode);
 extern int schedule_hrtimeout(ktime_t *expires, const enum hrtimer_mode mode);
 
 /* Soft interrupt function to run the hrtimer queues: */
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ae307feec74c..01483004183d 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1309,7 +1309,20 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 
 			timer = rb_entry(node, struct hrtimer, node);
 
-			if (basenow.tv64 < hrtimer_get_expires_tv64(timer)) {
+			/*
+			 * The immediate goal for using the softexpires is
+			 * minimizing wakeups, not running timers at the
+			 * earliest interrupt after their soft expiration.
+			 * This allows us to avoid using a Priority Search
+			 * Tree, which can answer a stabbing querry for
+			 * overlapping intervals and instead use the simple
+			 * BST we already have.
+			 * We don't add extra wakeups by delaying timers that
+			 * are right-of a not yet expired timer, because that
+			 * timer will have to trigger a wakeup anyway.
+			 */
+
+			if (basenow.tv64 < hrtimer_get_softexpires_tv64(timer)) {
 				ktime_t expires;
 
 				expires = ktime_sub(hrtimer_get_expires(timer),
@@ -1681,14 +1694,20 @@ void __init hrtimers_init(void)
 }
 
 /**
- * schedule_hrtimeout - sleep until timeout
+ * schedule_hrtimeout_range - sleep until timeout
  * @expires:	timeout value (ktime_t)
+ * @delta:	slack in expires timeout (ktime_t)
  * @mode:	timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
  *
  * Make the current task sleep until the given expiry time has
  * elapsed. The routine will return immediately unless
  * the current task state has been set (see set_current_state()).
  *
+ * The @delta argument gives the kernel the freedom to schedule the
+ * actual wakeup to a time that is both power and performance friendly.
+ * The kernel give the normal best effort behavior for "@expires+@delta",
+ * but may decide to fire the timer earlier, but no earlier than @expires.
+ *
  * You can set the task state as follows -
  *
  * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
@@ -1702,7 +1721,7 @@ void __init hrtimers_init(void)
  *
  * Returns 0 when the timer has expired otherwise -EINTR
  */
-int __sched schedule_hrtimeout(ktime_t *expires,
+int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta,
 			       const enum hrtimer_mode mode)
 {
 	struct hrtimer_sleeper t;
@@ -1726,7 +1745,7 @@ int __sched schedule_hrtimeout(ktime_t *expires,
 	}
 
 	hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC, mode);
-	hrtimer_set_expires(&t.timer, *expires);
+	hrtimer_set_expires_range_ns(&t.timer, *expires, delta);
 
 	hrtimer_init_sleeper(&t, current);
 
@@ -1744,4 +1763,33 @@ int __sched schedule_hrtimeout(ktime_t *expires,
 
 	return !t.task ? 0 : -EINTR;
 }
+EXPORT_SYMBOL_GPL(schedule_hrtimeout_range);
+
+/**
+ * schedule_hrtimeout - sleep until timeout
+ * @expires:	timeout value (ktime_t)
+ * @mode:	timer mode, HRTIMER_MODE_ABS or HRTIMER_MODE_REL
+ *
+ * Make the current task sleep until the given expiry time has
+ * elapsed. The routine will return immediately unless
+ * the current task state has been set (see set_current_state()).
+ *
+ * You can set the task state as follows -
+ *
+ * %TASK_UNINTERRUPTIBLE - at least @timeout time is guaranteed to
+ * pass before the routine returns.
+ *
+ * %TASK_INTERRUPTIBLE - the routine may return early if a signal is
+ * delivered to the current task.
+ *
+ * The current task state is guaranteed to be TASK_RUNNING when this
+ * routine returns.
+ *
+ * Returns 0 when the timer has expired otherwise -EINTR
+ */
+int __sched schedule_hrtimeout(ktime_t *expires,
+			       const enum hrtimer_mode mode)
+{
+	return schedule_hrtimeout_range(expires, 0, mode);
+}
 EXPORT_SYMBOL_GPL(schedule_hrtimeout);
-- 
cgit v1.2.3-58-ga151


From 6976675d94042fbd446231d1bd8b7de71a980ada Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 1 Sep 2008 15:52:40 -0700
Subject: hrtimer: create a "timer_slack" field in the task struct

We want to be able to control the default "rounding" that is used by
select() and poll() and friends. This is a per process property
(so that we can have a "nice" like program to start certain programs with
a looser or stricter rounding) that can be set/get via a prctl().

For this purpose, a field called "timer_slack_ns" is added to the task
struct. In addition, a field called "default_timer_slack"ns" is added
so that tasks easily can temporarily to a more/less accurate slack and then
back to the default.

The default value of the slack is set to 50 usec; this is significantly less
than 2.6.27's average select() and poll() timing error but still allows
the kernel to group timers somewhat to preserve power behavior. Applications
and admins can override this via the prctl()

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 include/linux/init_task.h |  1 +
 include/linux/prctl.h     |  7 +++++++
 include/linux/sched.h     |  6 ++++++
 kernel/fork.c             |  2 ++
 kernel/sys.c              | 10 ++++++++++
 5 files changed, 26 insertions(+)

(limited to 'kernel')

diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 021d8e720c79..23fd8909b9e5 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -170,6 +170,7 @@ extern struct group_info init_groups;
 	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
 	.fs_excl	= ATOMIC_INIT(0),				\
 	.pi_lock	= __SPIN_LOCK_UNLOCKED(tsk.pi_lock),		\
+	.timer_slack_ns = 50000, /* 50 usec default slack */		\
 	.pids = {							\
 		[PIDTYPE_PID]  = INIT_PID_LINK(PIDTYPE_PID),		\
 		[PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID),		\
diff --git a/include/linux/prctl.h b/include/linux/prctl.h
index 5ad79198d6f9..48d887e3c6e7 100644
--- a/include/linux/prctl.h
+++ b/include/linux/prctl.h
@@ -78,4 +78,11 @@
 #define PR_GET_SECUREBITS 27
 #define PR_SET_SECUREBITS 28
 
+/*
+ * Get/set the timerslack as used by poll/select/nanosleep
+ * A value of 0 means "use default"
+ */
+#define PR_SET_TIMERSLACK 29
+#define PR_GET_TIMERSLACK 30
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3d9120c5ad15..dcc03fd5a7f3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1301,6 +1301,12 @@ struct task_struct {
 	int latency_record_count;
 	struct latency_record latency_record[LT_SAVECOUNT];
 #endif
+	/*
+	 * time slack values; these are used to round up poll() and
+	 * select() etc timeout values. These are in nanoseconds.
+	 */
+	unsigned long timer_slack_ns;
+	unsigned long default_timer_slack_ns;
 };
 
 /*
diff --git a/kernel/fork.c b/kernel/fork.c
index 7ce2ebe84796..4308d75f0fa5 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -987,6 +987,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	p->prev_utime = cputime_zero;
 	p->prev_stime = cputime_zero;
 
+	p->default_timer_slack_ns = current->timer_slack_ns;
+
 #ifdef CONFIG_DETECT_SOFTLOCKUP
 	p->last_switch_count = 0;
 	p->last_switch_timestamp = 0;
diff --git a/kernel/sys.c b/kernel/sys.c
index 038a7bc0901d..1b96401a0576 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1727,6 +1727,16 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 		case PR_SET_TSC:
 			error = SET_TSC_CTL(arg2);
 			break;
+		case PR_GET_TIMERSLACK:
+			error = current->timer_slack_ns;
+			break;
+		case PR_SET_TIMERSLACK:
+			if (arg2 <= 0)
+				current->timer_slack_ns =
+					current->default_timer_slack_ns;
+			else
+				current->timer_slack_ns = arg2;
+			break;
 		default:
 			error = -EINVAL;
 			break;
-- 
cgit v1.2.3-58-ga151


From da8f2e170ea94cc20f8ebbc8ee8d127edb8f12f1 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 7 Sep 2008 10:47:46 -0700
Subject: hrtimer: add a hrtimer_start_range() function

this patch adds a _range version of hrtimer_start() so that range timers
can be created; the hrtimer_start() function is just a wrapper around this.

In addition, hrtimer_start_expires() will now preserve existing ranges.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 include/linux/hrtimer.h |  9 ++++++++-
 kernel/hrtimer.c        | 26 +++++++++++++++++++++++---
 2 files changed, 31 insertions(+), 4 deletions(-)

(limited to 'kernel')

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 4c1a834b9849..1c0473e8ecb4 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -350,13 +350,20 @@ static inline void destroy_hrtimer_on_stack(struct hrtimer *timer) { }
 /* Basic timer operations: */
 extern int hrtimer_start(struct hrtimer *timer, ktime_t tim,
 			 const enum hrtimer_mode mode);
+extern int hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
+			unsigned long range_ns, const enum hrtimer_mode mode);
 extern int hrtimer_cancel(struct hrtimer *timer);
 extern int hrtimer_try_to_cancel(struct hrtimer *timer);
 
 static inline int hrtimer_start_expires(struct hrtimer *timer,
 						enum hrtimer_mode mode)
 {
-	return hrtimer_start(timer, hrtimer_get_expires(timer), mode);
+	unsigned long delta;
+	ktime_t soft, hard;
+	soft = hrtimer_get_softexpires(timer);
+	hard = hrtimer_get_expires(timer);
+	delta = ktime_to_ns(ktime_sub(hard, soft));
+	return hrtimer_start_range_ns(timer, hrtimer_get_expires(timer), delta, mode);
 }
 
 static inline int hrtimer_restart(struct hrtimer *timer)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 01483004183d..a0222097c57e 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -945,9 +945,10 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
 }
 
 /**
- * hrtimer_start - (re)start an relative timer on the current CPU
+ * hrtimer_start_range_ns - (re)start an relative timer on the current CPU
  * @timer:	the timer to be added
  * @tim:	expiry time
+ * @delta_ns:	"slack" range for the timer
  * @mode:	expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
  *
  * Returns:
@@ -955,7 +956,8 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
  *  1 when the timer was active
  */
 int
-hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
+hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_ns,
+			const enum hrtimer_mode mode)
 {
 	struct hrtimer_clock_base *base, *new_base;
 	unsigned long flags;
@@ -983,7 +985,7 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 #endif
 	}
 
-	hrtimer_set_expires(timer, tim);
+	hrtimer_set_expires_range_ns(timer, tim, delta_ns);
 
 	timer_stats_hrtimer_set_start_info(timer);
 
@@ -1016,8 +1018,26 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
+
+/**
+ * hrtimer_start - (re)start an relative timer on the current CPU
+ * @timer:	the timer to be added
+ * @tim:	expiry time
+ * @mode:	expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
+ *
+ * Returns:
+ *  0 on success
+ *  1 when the timer was active
+ */
+int
+hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
+{
+	return hrtimer_start_range_ns(timer, tim, 0, mode);
+}
 EXPORT_SYMBOL_GPL(hrtimer_start);
 
+
 /**
  * hrtimer_try_to_cancel - try to deactivate a timer
  * @timer:	hrtimer to stop
-- 
cgit v1.2.3-58-ga151


From 704af52bd13a5d9f3c60c496c68e752fafdfb434 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 7 Sep 2008 16:10:20 -0700
Subject: hrtimer: show the timer ranges in /proc/timer_list

to help debugging and visibility of timer ranges, show them
in the existing timer list in /proc/timer_list

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/time/timer_list.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 5224a3215fb7..122ee751d2d1 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -65,8 +65,10 @@ print_timer(struct seq_file *m, struct hrtimer *timer, int idx, u64 now)
 	SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
 #endif
 	SEQ_printf(m, "\n");
-	SEQ_printf(m, " # expires at %Lu nsecs [in %Ld nsecs]\n",
+	SEQ_printf(m, " # expires at %Lu-%Lu nsecs [in %Ld to %Ld nsecs]\n",
+		(unsigned long long)ktime_to_ns(hrtimer_get_softexpires(timer)),
 		(unsigned long long)ktime_to_ns(hrtimer_get_expires(timer)),
+		(long long)(ktime_to_ns(hrtimer_get_softexpires(timer)) - now),
 		(long long)(ktime_to_ns(hrtimer_get_expires(timer)) - now));
 }
 
-- 
cgit v1.2.3-58-ga151


From 3bd012060f962567aadb52b27b2fc8fdc91102c7 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 8 Sep 2008 08:58:59 -0700
Subject: hrtimer: make the nanosleep() syscall use the per process slack

This patch makes the nanosleep() system call use the per process
slack value; with this users are able to externally control existing
applications to reduce the wakeup rate.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/hrtimer.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index a0222097c57e..9a4c90185566 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1563,9 +1563,14 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 	struct restart_block *restart;
 	struct hrtimer_sleeper t;
 	int ret = 0;
+	unsigned long slack;
+
+	slack = current->timer_slack_ns;
+	if (rt_task(current))
+		slack = 0;
 
 	hrtimer_init_on_stack(&t.timer, clockid, mode);
-	hrtimer_set_expires(&t.timer, timespec_to_ktime(*rqtp));
+	hrtimer_set_expires_range_ns(&t.timer, timespec_to_ktime(*rqtp), slack);
 	if (do_nanosleep(&t, mode))
 		goto out;
 
-- 
cgit v1.2.3-58-ga151


From ae4b748e81b7e366f04f55229d5e372e372c33af Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 8 Sep 2008 09:03:57 -0700
Subject: hrtimer: make the futex() system call use the per process slack value

This patch makes the futex() system call use the per process
slack value; with this users are able to externally control existing
applications to reduce the wakeup rate.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/futex.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/futex.c b/kernel/futex.c
index 4cd5b4319b04..8af10027514b 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1296,10 +1296,14 @@ static int futex_wait(u32 __user *uaddr, struct rw_semaphore *fshared,
 		if (!abs_time)
 			schedule();
 		else {
+			unsigned long slack;
+			slack = current->timer_slack_ns;
+			if (rt_task(current))
+				slack = 0;
 			hrtimer_init_on_stack(&t.timer, CLOCK_MONOTONIC,
 						HRTIMER_MODE_ABS);
 			hrtimer_init_sleeper(&t, current);
-			hrtimer_set_expires(&t.timer, *abs_time);
+			hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
 
 			hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
 			if (!hrtimer_active(&t.timer))
-- 
cgit v1.2.3-58-ga151


From 2e94d1f71f7e4404d997e6fb4f1618aa147d76f9 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Wed, 10 Sep 2008 16:06:00 -0700
Subject: hrtimer: peek at the timer queue just before going idle

As part of going idle, we already look at the time of the next timer event to determine
which C-state to select etc.

This patch adds functionality that causes the timers that are past their
soft expire time, to fire at this time, before we calculate the next wakeup
time. This functionality will thus avoid wakeups by running timers before
going idle rather than specially waking up for it.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 drivers/cpuidle/cpuidle.c |  7 +++++++
 include/linux/hrtimer.h   |  5 +++++
 kernel/hrtimer.c          | 30 ++++++++++++++++++++++++++++++
 3 files changed, 42 insertions(+)

(limited to 'kernel')

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 5ce07b517c58..2e3148499368 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -16,6 +16,7 @@
 #include <linux/cpu.h>
 #include <linux/cpuidle.h>
 #include <linux/ktime.h>
+#include <linux/hrtimer.h>
 
 #include "cpuidle.h"
 
@@ -60,6 +61,12 @@ static void cpuidle_idle_call(void)
 		return;
 	}
 
+	/*
+	 * run any timers that can be run now, at this point
+	 * before calculating the idle duration etc.
+	 */
+	hrtimer_peek_ahead_timers();
+
 	/* ask the governor for the next state */
 	next_state = cpuidle_curr_governor->select(dev);
 	if (need_resched())
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 95db11f62ff2..d93b1e1dc169 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -326,6 +326,11 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer)
 extern ktime_t ktime_get(void);
 extern ktime_t ktime_get_real(void);
 
+
+DECLARE_PER_CPU(struct tick_device, tick_cpu_device);
+extern void hrtimer_peek_ahead_timers(void);
+
+
 /* Exported timer functions: */
 
 /* Initialize timers: */
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 9a4c90185566..eb2cf984959f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1381,6 +1381,36 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 		raise_softirq(HRTIMER_SOFTIRQ);
 }
 
+/**
+ * hrtimer_peek_ahead_timers -- run soft-expired timers now
+ *
+ * hrtimer_peek_ahead_timers will peek at the timer queue of
+ * the current cpu and check if there are any timers for which
+ * the soft expires time has passed. If any such timers exist,
+ * they are run immediately and then removed from the timer queue.
+ *
+ */
+void hrtimer_peek_ahead_timers(void)
+{
+	unsigned long flags;
+	struct tick_device *td;
+	struct clock_event_device *dev;
+
+	if (hrtimer_hres_active())
+		return;
+
+	local_irq_save(flags);
+	td = &__get_cpu_var(tick_cpu_device);
+	if (!td)
+		goto out;
+	dev = td->evtdev;
+	if (!dev)
+		goto out;
+	hrtimer_interrupt(dev);
+out:
+	local_irq_restore(flags);
+}
+
 static void run_hrtimer_softirq(struct softirq_action *h)
 {
 	run_hrtimer_pending(&__get_cpu_var(hrtimer_bases));
-- 
cgit v1.2.3-58-ga151


From 030aebd2e439a2ebcca2b0ce30a02ed84feb043e Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sat, 11 Oct 2008 12:25:45 -0700
Subject: rangetimer: fix BUG_ON reported by Ingo

There's a small race/chance that, while hrtimers are enabled globally,
they're later not enabled when we're calling the hrtimer_interrupt() function,
which then BUG_ON()'s for that. This patch closes that race/gap.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/hrtimer.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index eb2cf984959f..b17657d8d81a 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1395,11 +1395,15 @@ void hrtimer_peek_ahead_timers(void)
 	unsigned long flags;
 	struct tick_device *td;
 	struct clock_event_device *dev;
-
+	struct hrtimer_cpu_base *cpu_base;
 	if (hrtimer_hres_active())
 		return;
 
 	local_irq_save(flags);
+	cpu_base = &__get_cpu_var(hrtimer_bases);
+	if (!cpu_base->hres_active)
+		goto out;
+
 	td = &__get_cpu_var(tick_cpu_device);
 	if (!td)
 		goto out;
-- 
cgit v1.2.3-58-ga151


From dc4304f7deee29fcdf6a2b62f7146ea7f505fd42 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Mon, 13 Oct 2008 10:32:15 -0400
Subject: rangetimers: fix the bug reported by Ingo for real

and please hand me a brown paper bag

(thanks to Thomas for pointing out this very obvious bug)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 kernel/hrtimer.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index b17657d8d81a..2bd230be1cb5 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1395,15 +1395,11 @@ void hrtimer_peek_ahead_timers(void)
 	unsigned long flags;
 	struct tick_device *td;
 	struct clock_event_device *dev;
-	struct hrtimer_cpu_base *cpu_base;
-	if (hrtimer_hres_active())
+
+	if (!hrtimer_hres_active())
 		return;
 
 	local_irq_save(flags);
-	cpu_base = &__get_cpu_var(hrtimer_bases);
-	if (!cpu_base->hres_active)
-		goto out;
-
 	td = &__get_cpu_var(tick_cpu_device);
 	if (!td)
 		goto out;
-- 
cgit v1.2.3-58-ga151


From e1dd7bc58578ebfcaba989608017fe5156c29c86 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 20 Oct 2008 13:33:36 +0200
Subject: hrtimers: fix docbook comments

hrtimer_start() and hrtimer_start_range_ns() handle relative and
absolute timers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/hrtimer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 51ee90bca2de..00e6f0a1e7a3 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -946,7 +946,7 @@ remove_hrtimer(struct hrtimer *timer, struct hrtimer_clock_base *base)
 }
 
 /**
- * hrtimer_start_range_ns - (re)start an relative timer on the current CPU
+ * hrtimer_start_range_ns - (re)start an hrtimer on the current CPU
  * @timer:	the timer to be added
  * @tim:	expiry time
  * @delta_ns:	"slack" range for the timer
@@ -1022,7 +1022,7 @@ hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, unsigned long delta_n
 EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
 
 /**
- * hrtimer_start - (re)start an relative timer on the current CPU
+ * hrtimer_start - (re)start an hrtimer on the current CPU
  * @timer:	the timer to be added
  * @tim:	expiry time
  * @mode:	expiry mode: absolute (HRTIMER_ABS) or relative (HRTIMER_REL)
-- 
cgit v1.2.3-58-ga151


From 643bdf68f92a8516574ed7ca3713f9334c331b8d Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 20 Oct 2008 13:38:11 +0200
Subject: hrtimers: simplify hrtimer_peek_ahead_timers()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/hrtimer.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

(limited to 'kernel')

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 00e6f0a1e7a3..4fc41414fc06 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1394,22 +1394,16 @@ void hrtimer_interrupt(struct clock_event_device *dev)
  */
 void hrtimer_peek_ahead_timers(void)
 {
-	unsigned long flags;
 	struct tick_device *td;
-	struct clock_event_device *dev;
+	unsigned long flags;
 
 	if (!hrtimer_hres_active())
 		return;
 
 	local_irq_save(flags);
 	td = &__get_cpu_var(tick_cpu_device);
-	if (!td)
-		goto out;
-	dev = td->evtdev;
-	if (!dev)
-		goto out;
-	hrtimer_interrupt(dev);
-out:
+	if (td && td->evtdev)
+		hrtimer_interrupt(td->evtdev);
 	local_irq_restore(flags);
 }
 
-- 
cgit v1.2.3-58-ga151