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

2 files changed, 16 insertions, 8 deletions

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index f61402b1f2d0..73961f35fdc8 100644
--- a/kernel/time/clocksource.c
+++ b/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));
                         }
                 }
         }
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 686da821d376..69dba0c71727 100644
--- a/kernel/time/tick-sched.c
+++ b/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;