1 files changed, 48 insertions, 8 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index c01e568935ea..a7f07d5a6241 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -38,6 +38,7 @@
 #include <linux/tick.h>
 #include <linux/kallsyms.h>
 #include <linux/perf_counter.h>
+#include <linux/sched.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -379,6 +380,8 @@ static void timer_stats_account_timer(struct timer_list *timer)
 {
         unsigned int flag = 0;
 
+        if (likely(!timer->start_site))
+                return;
         if (unlikely(tbase_get_deferrable(timer->base)))
                 flag |= TIMER_STATS_FLAG_DEFERRABLE;
 
@@ -605,13 +608,12 @@ static struct tvec_base *lock_timer_base(struct timer_list *timer,
 }
 
 static inline int
-__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
+__mod_timer(struct timer_list *timer, unsigned long expires,
+                                                bool pending_only, int pinned)
 {
         struct tvec_base *base, *new_base;
         unsigned long flags;
-        int ret;
-
-        ret = 0;
+        int ret = 0 , cpu;
 
         timer_stats_timer_set_start_info(timer);
         BUG_ON(!timer->function);
@@ -630,6 +632,18 @@ __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only)
 
         new_base = __get_cpu_var(tvec_bases);
 
+        cpu = smp_processor_id();
+
+#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
+        if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu)) {
+                int preferred_cpu = get_nohz_load_balancer();
+
+                if (preferred_cpu >= 0)
+                        cpu = preferred_cpu;
+        }
+#endif
+        new_base = per_cpu(tvec_bases, cpu);
+
         if (base != new_base) {
                 /*
                  * We are trying to schedule the timer on the local CPU.
@@ -669,7 +683,7 @@ out_unlock:
  */
 int mod_timer_pending(struct timer_list *timer, unsigned long expires)
 {
-        return __mod_timer(timer, expires, true);
+        return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
 }
 EXPORT_SYMBOL(mod_timer_pending);
 
@@ -700,14 +714,36 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
          * networking code - if the timer is re-modified
          * to be the same thing then just return:
          */
-        if (timer->expires == expires && timer_pending(timer))
+        if (timer_pending(timer) && timer->expires == expires)
                 return 1;
 
-        return __mod_timer(timer, expires, false);
+        return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
 }
 EXPORT_SYMBOL(mod_timer);
 
 /**
+ * mod_timer_pinned - modify a timer's timeout
+ * @timer: the timer to be modified
+ * @expires: new timeout in jiffies
+ *
+ * mod_timer_pinned() is a way to update the expire field of an
+ * active timer (if the timer is inactive it will be activated)
+ * and not allow the timer to be migrated to a different CPU.
+ *
+ * mod_timer_pinned(timer, expires) is equivalent to:
+ *
+ *     del_timer(timer); timer->expires = expires; add_timer(timer);
+ */
+int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
+{
+        if (timer->expires == expires && timer_pending(timer))
+                return 1;
+
+        return __mod_timer(timer, expires, false, TIMER_PINNED);
+}
+EXPORT_SYMBOL(mod_timer_pinned);
+
+/**
  * add_timer - start a timer
  * @timer: the timer to be added
  *
@@ -757,6 +793,7 @@ void add_timer_on(struct timer_list *timer, int cpu)
         wake_up_idle_cpu(cpu);
         spin_unlock_irqrestore(&base->lock, flags);
 }
+EXPORT_SYMBOL_GPL(add_timer_on);
 
 /**
  * del_timer - deactive a timer.
@@ -1016,6 +1053,9 @@ cascade:
                 index = slot = timer_jiffies & TVN_MASK;
                 do {
                         list_for_each_entry(nte, varp->vec + slot, entry) {
+                                if (tbase_get_deferrable(nte->base))
+                                        continue;
+
                                 found = 1;
                                 if (time_before(nte->expires, expires))
                                         expires = nte->expires;
@@ -1306,7 +1346,7 @@ signed long __sched schedule_timeout(signed long timeout)
         expire = timeout + jiffies;
 
         setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
-        __mod_timer(&timer, expire, false);
+        __mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
         schedule();
         del_singleshot_timer_sync(&timer);