[PATCH] more SPIN_LOCK_UNLOCKED -> DEFINE_SPINLOCK conversions

[pandora-kernel.git] / kernel / timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 51ff917..13e2b51 100644 (file)
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -950,6 +950,7 @@ void do_timer(struct pt_regs *regs)
 {
        jiffies_64++;
        update_times();
+       softlockup_tick(regs);
 }
 
 #ifdef __ARCH_WANT_SYS_ALARM
@@ -1023,7 +1024,7 @@ asmlinkage long sys_getppid(void)
        parent = me->group_leader->real_parent;
        for (;;) {
                pid = parent->tgid;
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
 {
                struct task_struct *old = parent;
 
@@ -1428,7 +1429,7 @@ static inline u64 time_interpolator_get_cycles(unsigned int src)
        }
 }
 
-static inline u64 time_interpolator_get_counter(void)
+static inline u64 time_interpolator_get_counter(int writelock)
 {
        unsigned int src = time_interpolator->source;
 
@@ -1442,6 +1443,15 @@ static inline u64 time_interpolator_get_counter(void)
                        now = time_interpolator_get_cycles(src);
                        if (lcycle && time_after(lcycle, now))
                                return lcycle;
+
+                       /* When holding the xtime write lock, there's no need
+                        * to add the overhead of the cmpxchg.  Readers are
+                        * force to retry until the write lock is released.
+                        */
+                       if (writelock) {
+                               time_interpolator->last_cycle = now;
+                               return now;
+                       }
                        /* Keep track of the last timer value returned. The use of cmpxchg here
                         * will cause contention in an SMP environment.
                         */
@@ -1455,7 +1465,7 @@ static inline u64 time_interpolator_get_counter(void)
 void time_interpolator_reset(void)
 {
        time_interpolator->offset = 0;
-       time_interpolator->last_counter = time_interpolator_get_counter();
+       time_interpolator->last_counter = time_interpolator_get_counter(1);
 }
 
 #define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
@@ -1467,7 +1477,7 @@ unsigned long time_interpolator_get_offset(void)
                return 0;
 
        return time_interpolator->offset +
-               GET_TI_NSECS(time_interpolator_get_counter(), time_interpolator);
+               GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
 }
 
 #define INTERPOLATOR_ADJUST 65536
@@ -1490,7 +1500,7 @@ static void time_interpolator_update(long delta_nsec)
         * and the tuning logic insures that.
          */
 
-       counter = time_interpolator_get_counter();
+       counter = time_interpolator_get_counter(1);
        offset = time_interpolator->offset + GET_TI_NSECS(counter, time_interpolator);
 
        if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
@@ -1597,7 +1607,7 @@ void msleep(unsigned int msecs)
 EXPORT_SYMBOL(msleep);
 
 /**
- * msleep_interruptible - sleep waiting for waitqueue interruptions
+ * msleep_interruptible - sleep waiting for signals
  * @msecs: Time in milliseconds to sleep for
  */
 unsigned long msleep_interruptible(unsigned int msecs)