Merge git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt

* git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt:
  clocksource: make clocksource watchdog cycle through online CPUs
  Documentation: move timer related documentation to a single place
  clockevents: optimise tick_nohz_stop_sched_tick() a bit
  locking: remove unused double_spin_lock()
  hrtimers: simplify lockdep handling
  timers: simplify lockdep handling
  posix-timers: fix shadowed variables
  timer_list: add annotations to workqueue.c
  hrtimer: use nanosleep specific restart_block fields
  hrtimer: add nanosleep specific restart_block member

Documentation/00-INDEX

@@ -167,10 +167,8 @@ highuid.txt
 	- notes on the change from 16 bit to 32 bit user/group IDs.
 hpet.txt
 	- High Precision Event Timer Driver for Linux.
-hrtimer/
-	- info on the timer_stats debugging facility for timer (ab)use.
-hrtimers/
-	- info on the hrtimers subsystem for high-resolution kernel timers.
+timers/
+	- info on the timer related topics
 hw_random.txt
 	- info on Linux support for random number generator in i8xx chipsets.
 hwmon/

include/linux/hrtimer.h

@@ -173,7 +173,6 @@ struct hrtimer_clock_base {
  * struct hrtimer_cpu_base - the per cpu clock bases
  * @lock:		lock protecting the base and associated clock bases
  *			and timers
- * @lock_key:		the lock_class_key for use with lockdep
  * @clock_base:		array of clock bases for this cpu
  * @curr_timer:		the timer which is executing a callback right now
  * @expires_next:	absolute time of the next event which was scheduled
@@ -189,7 +188,6 @@ struct hrtimer_clock_base {
  */
 struct hrtimer_cpu_base {
 	spinlock_t			lock;
-	struct lock_class_key		lock_key;
 	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
 	struct list_head		cb_pending;
 #ifdef CONFIG_HIGH_RES_TIMERS

include/linux/spinlock.h

@@ -295,43 +295,6 @@ do {						\
 	1 : ({ local_irq_restore(flags); 0; }); \
 })
 
-/*
- * Locks two spinlocks l1 and l2.
- * l1_first indicates if spinlock l1 should be taken first.
- */
-static inline void double_spin_lock(spinlock_t *l1, spinlock_t *l2,
-				    bool l1_first)
-	__acquires(l1)
-	__acquires(l2)
-{
-	if (l1_first) {
-		spin_lock(l1);
-		spin_lock(l2);
-	} else {
-		spin_lock(l2);
-		spin_lock(l1);
-	}
-}
-
-/*
- * Unlocks two spinlocks l1 and l2.
- * l1_taken_first indicates if spinlock l1 was taken first and therefore
- * should be released after spinlock l2.
- */
-static inline void double_spin_unlock(spinlock_t *l1, spinlock_t *l2,
-				      bool l1_taken_first)
-	__releases(l1)
-	__releases(l2)
-{
-	if (l1_taken_first) {
-		spin_unlock(l2);
-		spin_unlock(l1);
-	} else {
-		spin_unlock(l1);
-		spin_unlock(l2);
-	}
-}
-
 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)

include/linux/thread_info.h

@@ -9,6 +9,9 @@
 
 #include <linux/types.h>
 
+struct timespec;
+struct compat_timespec;
+
 /*
  * System call restart block.
  */
@@ -26,6 +29,15 @@ struct restart_block {
 			u32 bitset;
 			u64 time;
 		} futex;
+		/* For nanosleep */
+		struct {
+			clockid_t index;
+			struct timespec __user *rmtp;
+#ifdef CONFIG_COMPAT
+			struct compat_timespec __user *compat_rmtp;
+#endif
+			u64 expires;
+		} nanosleep;
 	};
 };
 

kernel/compat.c

@@ -47,15 +47,14 @@ static long compat_nanosleep_restart(struct restart_block *restart)
 	mm_segment_t oldfs;
 	long ret;
 
-	rmtp = (struct compat_timespec __user *)(restart->arg1);
-	restart->arg1 = (unsigned long)&rmt;
+	restart->nanosleep.rmtp = (struct timespec __user *) &rmt;
 	oldfs = get_fs();
 	set_fs(KERNEL_DS);
 	ret = hrtimer_nanosleep_restart(restart);
 	set_fs(oldfs);
 
 	if (ret) {
-		restart->arg1 = (unsigned long)rmtp;
+		rmtp = restart->nanosleep.compat_rmtp;
 
 		if (rmtp && put_compat_timespec(&rmt, rmtp))
 			return -EFAULT;
@@ -89,7 +88,7 @@ asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
 			= &current_thread_info()->restart_block;
 
 		restart->fn = compat_nanosleep_restart;
-		restart->arg1 = (unsigned long)rmtp;
+		restart->nanosleep.compat_rmtp = rmtp;
 
 		if (rmtp && put_compat_timespec(&rmt, rmtp))
 			return -EFAULT;
@@ -607,9 +606,9 @@ static long compat_clock_nanosleep_restart(struct restart_block *restart)
 	long err;
 	mm_segment_t oldfs;
 	struct timespec tu;
-	struct compat_timespec *rmtp = (struct compat_timespec *)(restart->arg1);
+	struct compat_timespec *rmtp = restart->nanosleep.compat_rmtp;
 
-	restart->arg1 = (unsigned long) &tu;
+	restart->nanosleep.rmtp = (struct timespec __user *) &tu;
 	oldfs = get_fs();
 	set_fs(KERNEL_DS);
 	err = clock_nanosleep_restart(restart);
@@ -621,7 +620,7 @@ static long compat_clock_nanosleep_restart(struct restart_block *restart)
 
 	if (err == -ERESTART_RESTARTBLOCK) {
 		restart->fn = compat_clock_nanosleep_restart;
-		restart->arg1 = (unsigned long) rmtp;
+		restart->nanosleep.compat_rmtp = rmtp;
 	}
 	return err;
 }
@@ -652,7 +651,7 @@ long compat_sys_clock_nanosleep(clockid_t which_clock, int flags,
 	if (err == -ERESTART_RESTARTBLOCK) {
 		restart = &current_thread_info()->restart_block;
 		restart->fn = compat_clock_nanosleep_restart;
-		restart->arg1 = (unsigned long) rmtp;
+		restart->nanosleep.compat_rmtp = rmtp;
 	}
 	return err;
 }

kernel/hrtimer.c

@@ -1354,13 +1354,13 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	struct hrtimer_sleeper t;
 	struct timespec __user  *rmtp;
 
-	hrtimer_init(&t.timer, restart->arg0, HRTIMER_MODE_ABS);
-	t.timer.expires.tv64 = ((u64)restart->arg3 << 32) | (u64) restart->arg2;
+	hrtimer_init(&t.timer, restart->nanosleep.index, HRTIMER_MODE_ABS);
+	t.timer.expires.tv64 = restart->nanosleep.expires;
 
 	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
 		return 0;
 
-	rmtp = (struct timespec __user *)restart->arg1;
+	rmtp = restart->nanosleep.rmtp;
 	if (rmtp) {
 		int ret = update_rmtp(&t.timer, rmtp);
 		if (ret <= 0)
@@ -1394,10 +1394,9 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 
 	restart = &current_thread_info()->restart_block;
 	restart->fn = hrtimer_nanosleep_restart;
-	restart->arg0 = (unsigned long) t.timer.base->index;
-	restart->arg1 = (unsigned long) rmtp;
-	restart->arg2 = t.timer.expires.tv64 & 0xFFFFFFFF;
-	restart->arg3 = t.timer.expires.tv64 >> 32;
+	restart->nanosleep.index = t.timer.base->index;
+	restart->nanosleep.rmtp = rmtp;
+	restart->nanosleep.expires = t.timer.expires.tv64;
 
 	return -ERESTART_RESTARTBLOCK;
 }
@@ -1425,7 +1424,6 @@ static void __cpuinit init_hrtimers_cpu(int cpu)
 	int i;
 
 	spin_lock_init(&cpu_base->lock);
-	lockdep_set_class(&cpu_base->lock, &cpu_base->lock_key);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++)
 		cpu_base->clock_base[i].cpu_base = cpu_base;
@@ -1466,16 +1464,16 @@ static void migrate_hrtimers(int cpu)
 	tick_cancel_sched_timer(cpu);
 
 	local_irq_disable();
-	double_spin_lock(&new_base->lock, &old_base->lock,
-			 smp_processor_id() < cpu);
+	spin_lock(&new_base->lock);
+	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
 		migrate_hrtimer_list(&old_base->clock_base[i],
 				     &new_base->clock_base[i]);
 	}
 
-	double_spin_unlock(&new_base->lock, &old_base->lock,
-			   smp_processor_id() < cpu);
+	spin_unlock(&old_base->lock);
+	spin_unlock(&new_base->lock);
 	local_irq_enable();
 	put_cpu_var(hrtimer_bases);
 }

kernel/posix-cpu-timers.c

@@ -1087,45 +1087,45 @@ static void check_process_timers(struct task_struct *tsk,
 	maxfire = 20;
 	prof_expires = cputime_zero;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_first_entry(timers,
+		struct cpu_timer_list *tl = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
-		if (!--maxfire || cputime_lt(ptime, t->expires.cpu)) {
-			prof_expires = t->expires.cpu;
+		if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
+			prof_expires = tl->expires.cpu;
 			break;
 		}
-		t->firing = 1;
-		list_move_tail(&t->entry, firing);
+		tl->firing = 1;
+		list_move_tail(&tl->entry, firing);
 	}
 
 	++timers;
 	maxfire = 20;
 	virt_expires = cputime_zero;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_first_entry(timers,
+		struct cpu_timer_list *tl = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
-		if (!--maxfire || cputime_lt(utime, t->expires.cpu)) {
-			virt_expires = t->expires.cpu;
+		if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
+			virt_expires = tl->expires.cpu;
 			break;
 		}
-		t->firing = 1;
-		list_move_tail(&t->entry, firing);
+		tl->firing = 1;
+		list_move_tail(&tl->entry, firing);
 	}
 
 	++timers;
 	maxfire = 20;
 	sched_expires = 0;
 	while (!list_empty(timers)) {
-		struct cpu_timer_list *t = list_first_entry(timers,
+		struct cpu_timer_list *tl = list_first_entry(timers,
 						      struct cpu_timer_list,
 						      entry);
-		if (!--maxfire || sum_sched_runtime < t->expires.sched) {
-			sched_expires = t->expires.sched;
+		if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
+			sched_expires = tl->expires.sched;
 			break;
 		}
-		t->firing = 1;
-		list_move_tail(&t->entry, firing);
+		tl->firing = 1;
+		list_move_tail(&tl->entry, firing);
 	}
 
 	/*

kernel/time/clocksource.c

@@ -141,8 +141,16 @@ static void clocksource_watchdog(unsigned long data)
 	}
 
 	if (!list_empty(&watchdog_list)) {
-		__mod_timer(&watchdog_timer,
-			    watchdog_timer.expires + WATCHDOG_INTERVAL);
+		/*
+		 * Cycle through CPUs to check if the CPUs stay
+		 * synchronized to each other.
+		 */
+		int next_cpu = next_cpu(raw_smp_processor_id(), cpu_online_map);
+
+		if (next_cpu >= NR_CPUS)
+			next_cpu = first_cpu(cpu_online_map);
+		watchdog_timer.expires += WATCHDOG_INTERVAL;
+		add_timer_on(&watchdog_timer, next_cpu);
 	}
 	spin_unlock(&watchdog_lock);
 }
@@ -164,7 +172,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
 		if (!started && watchdog) {
 			watchdog_last = watchdog->read();
 			watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
-			add_timer(&watchdog_timer);
+			add_timer_on(&watchdog_timer,
+				     first_cpu(cpu_online_map));
 		}
 	} else {
 		if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
@@ -185,7 +194,8 @@ static void clocksource_check_watchdog(struct clocksource *cs)
 				watchdog_last = watchdog->read();
 				watchdog_timer.expires =
 					jiffies + WATCHDOG_INTERVAL;
-				add_timer(&watchdog_timer);
+				add_timer_on(&watchdog_timer,
+					     first_cpu(cpu_online_map));
 			}
 		}
 	}

kernel/time/tick-sched.c

@@ -158,9 +158,8 @@ void tick_nohz_stop_idle(int cpu)
 	}
 }
 
-static ktime_t tick_nohz_start_idle(int cpu)
+static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
 {
-	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
 	ktime_t now, delta;
 
 	now = ktime_get();
@@ -201,8 +200,8 @@ void tick_nohz_stop_sched_tick(void)
 	local_irq_save(flags);
 
 	cpu = smp_processor_id();
-	now = tick_nohz_start_idle(cpu);
 	ts = &per_cpu(tick_cpu_sched, cpu);
+	now = tick_nohz_start_idle(ts);
 
 	/*
 	 * If this cpu is offline and it is the one which updates
@@ -222,7 +221,6 @@ void tick_nohz_stop_sched_tick(void)
 	if (need_resched())
 		goto end;
 
-	cpu = smp_processor_id();
 	if (unlikely(local_softirq_pending())) {
 		static int ratelimit;
 

kernel/timer.c

@@ -1228,13 +1228,6 @@ asmlinkage long sys_sysinfo(struct sysinfo __user *info)
 	return 0;
 }
 
-/*
- * lockdep: we want to track each per-CPU base as a separate lock-class,
- * but timer-bases are kmalloc()-ed, so we need to attach separate
- * keys to them:
- */
-static struct lock_class_key base_lock_keys[NR_CPUS];
-
 static int __cpuinit init_timers_cpu(int cpu)
 {
 	int j;
@@ -1277,7 +1270,6 @@ static int __cpuinit init_timers_cpu(int cpu)
 	}
 
 	spin_lock_init(&base->lock);
-	lockdep_set_class(&base->lock, base_lock_keys + cpu);
 
 	for (j = 0; j < TVN_SIZE; j++) {
 		INIT_LIST_HEAD(base->tv5.vec + j);
@@ -1316,8 +1308,8 @@ static void __cpuinit migrate_timers(int cpu)
 	new_base = get_cpu_var(tvec_bases);
 
 	local_irq_disable();
-	double_spin_lock(&new_base->lock, &old_base->lock,
-			 smp_processor_id() < cpu);
+	spin_lock(&new_base->lock);
+	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
 	BUG_ON(old_base->running_timer);
 
@@ -1330,8 +1322,8 @@ static void __cpuinit migrate_timers(int cpu)
 		migrate_timer_list(new_base, old_base->tv5.vec + i);
 	}
 
-	double_spin_unlock(&new_base->lock, &old_base->lock,
-			   smp_processor_id() < cpu);
+	spin_unlock(&old_base->lock);
+	spin_unlock(&new_base->lock);
 	local_irq_enable();
 	put_cpu_var(tvec_bases);
 }

kernel/workqueue.c

@@ -219,6 +219,7 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 	struct timer_list *timer = &dwork->timer;
 	struct work_struct *work = &dwork->work;
 
+	timer_stats_timer_set_start_info(&dwork->timer);
 	if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
 		BUG_ON(timer_pending(timer));
 		BUG_ON(!list_empty(&work->entry));
@@ -580,6 +581,7 @@ EXPORT_SYMBOL(schedule_delayed_work);
 int schedule_delayed_work_on(int cpu,
 			struct delayed_work *dwork, unsigned long delay)
 {
+	timer_stats_timer_set_start_info(&dwork->timer);
 	return queue_delayed_work_on(cpu, keventd_wq, dwork, delay);
 }
 EXPORT_SYMBOL(schedule_delayed_work_on);