Merge with git+ssh://cvs.cs.unc.edu/cvs/proj/litmus/repo/litmus

Pulled in john's quantum alignment updates

1 files changed, 23 insertions, 0 deletions

diff --git a/kernel/timer.c b/kernel/timer.c
index c2a8ccfc28..532fdde9ba 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -737,6 +737,29 @@ static inline s64 __get_nsec_offset(void)
         return ns_offset;
 }
 
+/*
+ * Public, non-inline version of the above function, used within
+ * local timer interrupt handler to get an idea of the current
+ * timestamp without locking. (We can't lock and are only reading,
+ * so it can only hurt us, not others.)
+ */
+s64 get_nsec_offset(void)
+{
+        cycle_t cycle_now, cycle_delta;
+        s64 ns_offset;
+
+        /* read clocksource: */
+        cycle_now = clocksource_read(clock);
+
+        /* calculate the delta since the last update_wall_time: */
+        cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
+
+        /* convert to nanoseconds: */
+        ns_offset = cyc2ns(clock, cycle_delta);
+
+        return ns_offset;
+}
+
 /**
  * __get_realtime_clock_ts - Returns the time of day in a timespec
  * @ts:         pointer to the timespec to be set