X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Ftimer.c;h=13e2b513be019bf0b8b6b9218e4f268fff95f58a;hb=a9f6a0dd54efea2a5d57a27e6c232f9197c25154;hp=f2a11887a72680605bc9af158132a4fd104fbe24;hpb=62778ba1aa2589dc78c36a32edc6f5a6ccaf50c6;p=pandora-kernel.git

diff --git a/kernel/timer.c b/kernel/timer.c
index f2a11887a726..13e2b513be01 100644
--- 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)