7 files changed, 91 insertions, 27 deletions

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index a20dc8a3c949..fd42bd452b75 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -2,6 +2,55 @@
 # Timer subsystem related configuration options
 #
 
+# Options selectable by arch Kconfig
+
+# Watchdog function for clocksources to detect instabilities
+config CLOCKSOURCE_WATCHDOG
+        bool
+
+# Architecture has extra clocksource data
+config ARCH_CLOCKSOURCE_DATA
+        bool
+
+# Timekeeping vsyscall support
+config GENERIC_TIME_VSYSCALL
+        bool
+
+# ktime_t scalar 64bit nsec representation
+config KTIME_SCALAR
+        bool
+
+# Old style timekeeping
+config ARCH_USES_GETTIMEOFFSET
+        bool
+
+# The generic clock events infrastructure
+config GENERIC_CLOCKEVENTS
+        bool
+
+# Migration helper. Builds, but does not invoke
+config GENERIC_CLOCKEVENTS_BUILD
+        bool
+        default y
+        depends on GENERIC_CLOCKEVENTS
+
+# Clockevents broadcasting infrastructure
+config GENERIC_CLOCKEVENTS_BROADCAST
+        bool
+        depends on GENERIC_CLOCKEVENTS
+
+# Automatically adjust the min. reprogramming time for
+# clock event device
+config GENERIC_CLOCKEVENTS_MIN_ADJUST
+        bool
+
+# Generic update of CMOS clock
+config GENERIC_CMOS_UPDATE
+        bool
+
+if GENERIC_CLOCKEVENTS
+menu "Timers subsystem"
+
 # Core internal switch. Selected by NO_HZ / HIGH_RES_TIMERS. This is
 # only related to the tick functionality. Oneshot clockevent devices
 # are supported independ of this.
@@ -26,10 +75,5 @@ config HIGH_RES_TIMERS
           hardware is not capable then this option only increases
           the size of the kernel image.
 
-config GENERIC_CLOCKEVENTS_BUILD
-        bool
-        default y
-        depends on GENERIC_CLOCKEVENTS
-
-config GENERIC_CLOCKEVENTS_MIN_ADJUST
-        bool
+endmenu
+endif
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 8a538c55fc7b..aa27d391bfc8 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -59,7 +59,7 @@ static DEFINE_SPINLOCK(rtcdev_lock);
  * If one has not already been chosen, it checks to see if a
  * functional rtc device is available.
  */
-static struct rtc_device *alarmtimer_get_rtcdev(void)
+struct rtc_device *alarmtimer_get_rtcdev(void)
 {
         unsigned long flags;
         struct rtc_device *ret;
@@ -115,7 +115,7 @@ static void alarmtimer_rtc_interface_remove(void)
         class_interface_unregister(&alarmtimer_rtc_interface);
 }
 #else
-static inline struct rtc_device *alarmtimer_get_rtcdev(void)
+struct rtc_device *alarmtimer_get_rtcdev(void)
 {
         return NULL;
 }
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 9cd928f7a7c6..7e1ce012a851 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -297,8 +297,7 @@ void clockevents_register_device(struct clock_event_device *dev)
 }
 EXPORT_SYMBOL_GPL(clockevents_register_device);
 
-static void clockevents_config(struct clock_event_device *dev,
-                               u32 freq)
+void clockevents_config(struct clock_event_device *dev, u32 freq)
 {
         u64 sec;
 
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index f03fd83b170b..70b33abcc7bb 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -412,6 +412,7 @@ int second_overflow(unsigned long secs)
                 if (secs % 86400 == 0) {
                         leap = -1;
                         time_state = TIME_OOP;
+                        time_tai++;
                         printk(KERN_NOTICE
                                 "Clock: inserting leap second 23:59:60 UTC\n");
                 }
@@ -426,7 +427,6 @@ int second_overflow(unsigned long secs)
                 }
                 break;
         case TIME_OOP:
-                time_tai++;
                 time_state = TIME_WAIT;
                 break;
 
@@ -473,8 +473,6 @@ int second_overflow(unsigned long secs)
                                                          << NTP_SCALE_SHIFT;
         time_adjust = 0;
 
-
-
 out:
         spin_unlock_irqrestore(&ntp_lock, flags);
 
@@ -559,10 +557,10 @@ static inline void process_adj_status(struct timex *txc, struct timespec *ts)
         /* only set allowed bits */
         time_status &= STA_RONLY;
         time_status |= txc->status & ~STA_RONLY;
-
 }
+
 /*
- * Called with the xtime lock held, so we can access and modify
+ * Called with ntp_lock held, so we can access and modify
  * all the global NTP state:
  */
 static inline void process_adjtimex_modes(struct timex *txc, struct timespec *ts)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index bf57abdc7bd0..f113755695e2 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -346,7 +346,8 @@ int tick_resume_broadcast(void)
                                                      tick_get_broadcast_mask());
                         break;
                 case TICKDEV_MODE_ONESHOT:
-                        broadcast = tick_resume_broadcast_oneshot(bc);
+                        if (!cpumask_empty(tick_get_broadcast_mask()))
+                                broadcast = tick_resume_broadcast_oneshot(bc);
                         break;
                 }
         }
@@ -373,6 +374,9 @@ static int tick_broadcast_set_event(ktime_t expires, int force)
 {
         struct clock_event_device *bc = tick_broadcast_device.evtdev;
 
+        if (bc->mode != CLOCK_EVT_MODE_ONESHOT)
+                clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
+
         return clockevents_program_event(bc, expires, force);
 }
 
@@ -531,7 +535,6 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
                 int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
 
                 bc->event_handler = tick_handle_oneshot_broadcast;
-                clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
 
                 /* Take the do_timer update */
                 tick_do_timer_cpu = cpu;
@@ -549,6 +552,7 @@ void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
                            to_cpumask(tmpmask));
 
                 if (was_periodic && !cpumask_empty(to_cpumask(tmpmask))) {
+                        clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
                         tick_broadcast_init_next_event(to_cpumask(tmpmask),
                                                        tick_next_period);
                         tick_broadcast_set_event(tick_next_period, 1);
@@ -577,15 +581,10 @@ void tick_broadcast_switch_to_oneshot(void)
         raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
 
         tick_broadcast_device.mode = TICKDEV_MODE_ONESHOT;
-
-        if (cpumask_empty(tick_get_broadcast_mask()))
-                goto end;
-
         bc = tick_broadcast_device.evtdev;
         if (bc)
                 tick_broadcast_setup_oneshot(bc);
 
-end:
         raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }
 
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 6a3a5b9ff561..869997833928 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -274,6 +274,7 @@ EXPORT_SYMBOL_GPL(get_cpu_iowait_time_us);
 static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
 {
         unsigned long seq, last_jiffies, next_jiffies, delta_jiffies;
+        unsigned long rcu_delta_jiffies;
         ktime_t last_update, expires, now;
         struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
         u64 time_delta;
@@ -322,7 +323,7 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
                 time_delta = timekeeping_max_deferment();
         } while (read_seqretry(&xtime_lock, seq));
 
-        if (rcu_needs_cpu(cpu) || printk_needs_cpu(cpu) ||
+        if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || printk_needs_cpu(cpu) ||
             arch_needs_cpu(cpu)) {
                 next_jiffies = last_jiffies + 1;
                 delta_jiffies = 1;
@@ -330,6 +331,10 @@ static void tick_nohz_stop_sched_tick(struct tick_sched *ts)
                 /* Get the next timer wheel timer */
                 next_jiffies = get_next_timer_interrupt(last_jiffies);
                 delta_jiffies = next_jiffies - last_jiffies;
+                if (rcu_delta_jiffies < delta_jiffies) {
+                        next_jiffies = last_jiffies + rcu_delta_jiffies;
+                        delta_jiffies = rcu_delta_jiffies;
+                }
         }
         /*
          * Do not stop the tick, if we are only one off
@@ -576,6 +581,7 @@ void tick_nohz_idle_exit(void)
         /* Update jiffies first */
         select_nohz_load_balancer(0);
         tick_do_update_jiffies64(now);
+        update_cpu_load_nohz();
 
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
         /*
@@ -814,6 +820,16 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
         return HRTIMER_RESTART;
 }
 
+static int sched_skew_tick;
+
+static int __init skew_tick(char *str)
+{
+        get_option(&str, &sched_skew_tick);
+
+        return 0;
+}
+early_param("skew_tick", skew_tick);
+
 /**
  * tick_setup_sched_timer - setup the tick emulation timer
  */
@@ -831,6 +847,14 @@ void tick_setup_sched_timer(void)
         /* Get the next period (per cpu) */
         hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
 
+        /* Offset the tick to avert xtime_lock contention. */
+        if (sched_skew_tick) {
+                u64 offset = ktime_to_ns(tick_period) >> 1;
+                do_div(offset, num_possible_cpus());
+                offset *= smp_processor_id();
+                hrtimer_add_expires_ns(&ts->sched_timer, offset);
+        }
+
         for (;;) {
                 hrtimer_forward(&ts->sched_timer, now, tick_period);
                 hrtimer_start_expires(&ts->sched_timer,
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index d66b21308f7c..6f46a00a1e8a 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -240,7 +240,6 @@ void getnstimeofday(struct timespec *ts)
 
         timespec_add_ns(ts, nsecs);
 }
-
 EXPORT_SYMBOL(getnstimeofday);
 
 ktime_t ktime_get(void)
@@ -357,8 +356,8 @@ void do_gettimeofday(struct timeval *tv)
         tv->tv_sec = now.tv_sec;
         tv->tv_usec = now.tv_nsec/1000;
 }
-
 EXPORT_SYMBOL(do_gettimeofday);
+
 /**
  * do_settimeofday - Sets the time of day
  * @tv:         pointer to the timespec variable containing the new time
@@ -392,7 +391,6 @@ int do_settimeofday(const struct timespec *tv)
 
         return 0;
 }
-
 EXPORT_SYMBOL(do_settimeofday);
 
 
@@ -964,6 +962,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
                 timekeeper.xtime.tv_sec++;
                 leap = second_overflow(timekeeper.xtime.tv_sec);
                 timekeeper.xtime.tv_sec += leap;
+                timekeeper.wall_to_monotonic.tv_sec -= leap;
         }
 
         /* Accumulate raw time */
@@ -1079,6 +1078,7 @@ static void update_wall_time(void)
                 timekeeper.xtime.tv_sec++;
                 leap = second_overflow(timekeeper.xtime.tv_sec);
                 timekeeper.xtime.tv_sec += leap;
+                timekeeper.wall_to_monotonic.tv_sec -= leap;
         }
 
         timekeeping_update(false);