1 files changed, 186 insertions, 104 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index 8533c3796082..cb1b86a9c52f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -34,6 +34,8 @@
 #include <linux/cpu.h>
 #include <linux/syscalls.h>
 #include <linux/delay.h>
+#include <linux/tick.h>
+#include <linux/kallsyms.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -262,6 +264,18 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
         list_add_tail(&timer->entry, vec);
 }
 
+#ifdef CONFIG_TIMER_STATS
+void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
+{
+        if (timer->start_site)
+                return;
+
+        timer->start_site = addr;
+        memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
+        timer->start_pid = current->pid;
+}
+#endif
+
 /**
  * init_timer - initialize a timer.
  * @timer: the timer to be initialized
@@ -273,11 +287,16 @@ void fastcall init_timer(struct timer_list *timer)
 {
         timer->entry.next = NULL;
         timer->base = __raw_get_cpu_var(tvec_bases);
+#ifdef CONFIG_TIMER_STATS
+        timer->start_site = NULL;
+        timer->start_pid = -1;
+        memset(timer->start_comm, 0, TASK_COMM_LEN);
+#endif
 }
 EXPORT_SYMBOL(init_timer);
 
 static inline void detach_timer(struct timer_list *timer,
-                                        int clear_pending)
+                                int clear_pending)
 {
         struct list_head *entry = &timer->entry;
 
@@ -324,6 +343,7 @@ int __mod_timer(struct timer_list *timer, unsigned long expires)
         unsigned long flags;
         int ret = 0;
 
+        timer_stats_timer_set_start_info(timer);
         BUG_ON(!timer->function);
 
         base = lock_timer_base(timer, &flags);
@@ -374,6 +394,7 @@ void add_timer_on(struct timer_list *timer, int cpu)
         tvec_base_t *base = per_cpu(tvec_bases, cpu);
         unsigned long flags;
 
+        timer_stats_timer_set_start_info(timer);
         BUG_ON(timer_pending(timer) || !timer->function);
         spin_lock_irqsave(&base->lock, flags);
         timer->base = base;
@@ -406,6 +427,7 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
 {
         BUG_ON(!timer->function);
 
+        timer_stats_timer_set_start_info(timer);
         /*
          * This is a common optimization triggered by the
          * networking code - if the timer is re-modified
@@ -436,6 +458,7 @@ int del_timer(struct timer_list *timer)
         unsigned long flags;
         int ret = 0;
 
+        timer_stats_timer_clear_start_info(timer);
         if (timer_pending(timer)) {
                 base = lock_timer_base(timer, &flags);
                 if (timer_pending(timer)) {
@@ -569,6 +592,8 @@ static inline void __run_timers(tvec_base_t *base)
                         fn = timer->function;
                         data = timer->data;
 
+                        timer_stats_account_timer(timer);
+
                         set_running_timer(base, timer);
                         detach_timer(timer, 1);
                         spin_unlock_irq(&base->lock);
@@ -591,105 +616,124 @@ static inline void __run_timers(tvec_base_t *base)
         spin_unlock_irq(&base->lock);
 }
 
-#ifdef CONFIG_NO_IDLE_HZ
+#if defined(CONFIG_NO_IDLE_HZ) || defined(CONFIG_NO_HZ)
 /*
  * Find out when the next timer event is due to happen. This
  * is used on S/390 to stop all activity when a cpus is idle.
  * This functions needs to be called disabled.
  */
-unsigned long next_timer_interrupt(void)
+static unsigned long __next_timer_interrupt(tvec_base_t *base)
 {
-        tvec_base_t *base;
-        struct list_head *list;
+        unsigned long timer_jiffies = base->timer_jiffies;
+        unsigned long expires = timer_jiffies + (LONG_MAX >> 1);
+        int index, slot, array, found = 0;
         struct timer_list *nte;
-        unsigned long expires;
-        unsigned long hr_expires = MAX_JIFFY_OFFSET;
-        ktime_t hr_delta;
         tvec_t *varray[4];
-        int i, j;
-
-        hr_delta = hrtimer_get_next_event();
-        if (hr_delta.tv64 != KTIME_MAX) {
-                struct timespec tsdelta;
-                tsdelta = ktime_to_timespec(hr_delta);
-                hr_expires = timespec_to_jiffies(&tsdelta);
-                if (hr_expires < 3)
-                        return hr_expires + jiffies;
-        }
-        hr_expires += jiffies;
-
-        base = __get_cpu_var(tvec_bases);
-        spin_lock(&base->lock);
-        expires = base->timer_jiffies + (LONG_MAX >> 1);
-        list = NULL;
 
         /* Look for timer events in tv1. */
-        j = base->timer_jiffies & TVR_MASK;
+        index = slot = timer_jiffies & TVR_MASK;
         do {
-                list_for_each_entry(nte, base->tv1.vec + j, entry) {
+                list_for_each_entry(nte, base->tv1.vec + slot, entry) {
+                        found = 1;
                         expires = nte->expires;
-                        if (j < (base->timer_jiffies & TVR_MASK))
-                                list = base->tv2.vec + (INDEX(0));
-                        goto found;
+                        /* Look at the cascade bucket(s)? */
+                        if (!index || slot < index)
+                                goto cascade;
+                        return expires;
                 }
-                j = (j + 1) & TVR_MASK;
-        } while (j != (base->timer_jiffies & TVR_MASK));
+                slot = (slot + 1) & TVR_MASK;
+        } while (slot != index);
+
+cascade:
+        /* Calculate the next cascade event */
+        if (index)
+                timer_jiffies += TVR_SIZE - index;
+        timer_jiffies >>= TVR_BITS;
 
         /* Check tv2-tv5. */
         varray[0] = &base->tv2;
         varray[1] = &base->tv3;
         varray[2] = &base->tv4;
         varray[3] = &base->tv5;
-        for (i = 0; i < 4; i++) {
-                j = INDEX(i);
+
+        for (array = 0; array < 4; array++) {
+                tvec_t *varp = varray[array];
+
+                index = slot = timer_jiffies & TVN_MASK;
                 do {
-                        if (list_empty(varray[i]->vec + j)) {
-                                j = (j + 1) & TVN_MASK;
-                                continue;
-                        }
-                        list_for_each_entry(nte, varray[i]->vec + j, entry)
+                        list_for_each_entry(nte, varp->vec + slot, entry) {
+                                found = 1;
                                 if (time_before(nte->expires, expires))
                                         expires = nte->expires;
-                        if (j < (INDEX(i)) && i < 3)
-                                list = varray[i + 1]->vec + (INDEX(i + 1));
-                        goto found;
-                } while (j != (INDEX(i)));
-        }
-found:
-        if (list) {
-                /*
-                 * The search wrapped. We need to look at the next list
-                 * from next tv element that would cascade into tv element
-                 * where we found the timer element.
-                 */
-                list_for_each_entry(nte, list, entry) {
-                        if (time_before(nte->expires, expires))
-                                expires = nte->expires;
-                }
+                        }
+                        /*
+                         * Do we still search for the first timer or are
+                         * we looking up the cascade buckets ?
+                         */
+                        if (found) {
+                                /* Look at the cascade bucket(s)? */
+                                if (!index || slot < index)
+                                        break;
+                                return expires;
+                        }
+                        slot = (slot + 1) & TVN_MASK;
+                } while (slot != index);
+
+                if (index)
+                        timer_jiffies += TVN_SIZE - index;
+                timer_jiffies >>= TVN_BITS;
         }
-        spin_unlock(&base->lock);
+        return expires;
+}
 
-        /*
-         * It can happen that other CPUs service timer IRQs and increment
-         * jiffies, but we have not yet got a local timer tick to process
-         * the timer wheels.  In that case, the expiry time can be before
-         * jiffies, but since the high-resolution timer here is relative to
-         * jiffies, the default expression when high-resolution timers are
-         * not active,
-         *
-         *   time_before(MAX_JIFFY_OFFSET + jiffies, expires)
-         *
-         * would falsely evaluate to true.  If that is the case, just
-         * return jiffies so that we can immediately fire the local timer
-         */
-        if (time_before(expires, jiffies))
-                return jiffies;
+/*
+ * Check, if the next hrtimer event is before the next timer wheel
+ * event:
+ */
+static unsigned long cmp_next_hrtimer_event(unsigned long now,
+                                            unsigned long expires)
+{
+        ktime_t hr_delta = hrtimer_get_next_event();
+        struct timespec tsdelta;
+
+        if (hr_delta.tv64 == KTIME_MAX)
+                return expires;
 
-        if (time_before(hr_expires, expires))
-                return hr_expires;
+        if (hr_delta.tv64 <= TICK_NSEC)
+                return now;
 
+        tsdelta = ktime_to_timespec(hr_delta);
+        now += timespec_to_jiffies(&tsdelta);
+        if (time_before(now, expires))
+                return now;
         return expires;
 }
+
+/**
+ * next_timer_interrupt - return the jiffy of the next pending timer
+ */
+unsigned long get_next_timer_interrupt(unsigned long now)
+{
+        tvec_base_t *base = __get_cpu_var(tvec_bases);
+        unsigned long expires;
+
+        spin_lock(&base->lock);
+        expires = __next_timer_interrupt(base);
+        spin_unlock(&base->lock);
+
+        if (time_before_eq(expires, now))
+                return now;
+
+        return cmp_next_hrtimer_event(now, expires);
+}
+
+#ifdef CONFIG_NO_IDLE_HZ
+unsigned long next_timer_interrupt(void)
+{
+        return get_next_timer_interrupt(jiffies);
+}
+#endif
+
 #endif
 
 /******************************************************************/
@@ -832,32 +876,35 @@ EXPORT_SYMBOL(do_settimeofday);
  *
  * Accumulates current time interval and initializes new clocksource
  */
-static int change_clocksource(void)
+static void change_clocksource(void)
 {
         struct clocksource *new;
         cycle_t now;
         u64 nsec;
+
         new = clocksource_get_next();
-        if (clock != new) {
-                now = clocksource_read(new);
-                nsec =  __get_nsec_offset();
-                timespec_add_ns(&xtime, nsec);
-
-                clock = new;
-                clock->cycle_last = now;
-                printk(KERN_INFO "Time: %s clocksource has been installed.\n",
-                       clock->name);
-                return 1;
-        } else if (clock->update_callback) {
-                return clock->update_callback();
-        }
-        return 0;
+
+        if (clock == new)
+                return;
+
+        now = clocksource_read(new);
+        nsec =  __get_nsec_offset();
+        timespec_add_ns(&xtime, nsec);
+
+        clock = new;
+        clock->cycle_last = now;
+
+        clock->error = 0;
+        clock->xtime_nsec = 0;
+        clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
+
+        tick_clock_notify();
+
+        printk(KERN_INFO "Time: %s clocksource has been installed.\n",
+               clock->name);
 }
 #else
-static inline int change_clocksource(void)
-{
-        return 0;
-}
+static inline void change_clocksource(void) { }
 #endif
 
 /**
@@ -871,33 +918,56 @@ int timekeeping_is_continuous(void)
         do {
                 seq = read_seqbegin(&xtime_lock);
 
-                ret = clock->is_continuous;
+                ret = clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
 
         } while (read_seqretry(&xtime_lock, seq));
 
         return ret;
 }
 
+/**
+ * read_persistent_clock -  Return time in seconds from the persistent clock.
+ *
+ * Weak dummy function for arches that do not yet support it.
+ * Returns seconds from epoch using the battery backed persistent clock.
+ * Returns zero if unsupported.
+ *
+ *  XXX - Do be sure to remove it once all arches implement it.
+ */
+unsigned long __attribute__((weak)) read_persistent_clock(void)
+{
+        return 0;
+}
+
 /*
  * timekeeping_init - Initializes the clocksource and common timekeeping values
  */
 void __init timekeeping_init(void)
 {
         unsigned long flags;
+        unsigned long sec = read_persistent_clock();
 
         write_seqlock_irqsave(&xtime_lock, flags);
 
         ntp_clear();
 
         clock = clocksource_get_next();
-        clocksource_calculate_interval(clock, tick_nsec);
+        clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
         clock->cycle_last = clocksource_read(clock);
 
+        xtime.tv_sec = sec;
+        xtime.tv_nsec = 0;
+        set_normalized_timespec(&wall_to_monotonic,
+                -xtime.tv_sec, -xtime.tv_nsec);
+
         write_sequnlock_irqrestore(&xtime_lock, flags);
 }
 
-
+/* flag for if timekeeping is suspended */
 static int timekeeping_suspended;
+/* time in seconds when suspend began */
+static unsigned long timekeeping_suspend_time;
+
 /**
  * timekeeping_resume - Resumes the generic timekeeping subsystem.
  * @dev:        unused
@@ -909,13 +979,26 @@ static int timekeeping_suspended;
 static int timekeeping_resume(struct sys_device *dev)
 {
         unsigned long flags;
+        unsigned long now = read_persistent_clock();
 
         write_seqlock_irqsave(&xtime_lock, flags);
-        /* restart the last cycle value */
+
+        if (now && (now > timekeeping_suspend_time)) {
+                unsigned long sleep_length = now - timekeeping_suspend_time;
+
+                xtime.tv_sec += sleep_length;
+                wall_to_monotonic.tv_sec -= sleep_length;
+        }
+        /* re-base the last cycle value */
         clock->cycle_last = clocksource_read(clock);
         clock->error = 0;
         timekeeping_suspended = 0;
         write_sequnlock_irqrestore(&xtime_lock, flags);
+
+        touch_softlockup_watchdog();
+        /* Resume hrtimers */
+        clock_was_set();
+
         return 0;
 }
 
@@ -925,6 +1008,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
 
         write_seqlock_irqsave(&xtime_lock, flags);
         timekeeping_suspended = 1;
+        timekeeping_suspend_time = read_persistent_clock();
         write_sequnlock_irqrestore(&xtime_lock, flags);
         return 0;
 }
@@ -1089,11 +1173,8 @@ static void update_wall_time(void)
         clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
 
         /* check to see if there is a new clocksource to use */
-        if (change_clocksource()) {
-                clock->error = 0;
-                clock->xtime_nsec = 0;
-                clocksource_calculate_interval(clock, tick_nsec);
-        }
+        change_clocksource();
+        update_vsyscall(&xtime, clock);
 }
 
 /*
@@ -1162,11 +1243,9 @@ static inline void calc_load(unsigned long ticks)
  * This read-write spinlock protects us from races in SMP while
  * playing with xtime and avenrun.
  */
-#ifndef ARCH_HAVE_XTIME_LOCK
-__cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
+__attribute__((weak)) __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
 
 EXPORT_SYMBOL(xtime_lock);
-#endif
 
 /*
  * This function runs timers and the timer-tq in bottom half context.
@@ -1175,7 +1254,8 @@ static void run_timer_softirq(struct softirq_action *h)
 {
         tvec_base_t *base = __get_cpu_var(tvec_bases);
 
-        hrtimer_run_queues();
+        hrtimer_run_queues();
+
         if (time_after_eq(jiffies, base->timer_jiffies))
                 __run_timers(base);
 }
@@ -1621,6 +1701,8 @@ void __init init_timers(void)
         int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
                                 (void *)(long)smp_processor_id());
 
+        init_timer_stats();
+
         BUG_ON(err == NOTIFY_BAD);
         register_cpu_notifier(&timers_nb);
         open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);