Merge branch 'linus' into idle-test

1 files changed, 7 insertions, 2 deletions

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 49010d822f7..5bb86da8200 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -32,6 +32,8 @@ struct timekeeper {
 	cycle_t cycle_interval;
 	/* Number of clock shifted nano seconds in one NTP interval. */
 	u64	xtime_interval;
+	/* shifted nano seconds left over when rounding cycle_interval */
+	s64	xtime_remainder;
 	/* Raw nano seconds accumulated per NTP interval. */
 	u32	raw_interval;
 
@@ -62,7 +64,7 @@ struct timekeeper timekeeper;
 static void timekeeper_setup_internals(struct clocksource *clock)
 {
 	cycle_t interval;
-	u64 tmp;
+	u64 tmp, ntpinterval;
 
 	timekeeper.clock = clock;
 	clock->cycle_last = clock->read(clock);
@@ -70,6 +72,7 @@ static void timekeeper_setup_internals(struct clocksource *clock)
 	/* Do the ns -> cycle conversion first, using original mult */
 	tmp = NTP_INTERVAL_LENGTH;
 	tmp <<= clock->shift;
+	ntpinterval = tmp;
 	tmp += clock->mult/2;
 	do_div(tmp, clock->mult);
 	if (tmp == 0)
@@ -80,6 +83,7 @@ static void timekeeper_setup_internals(struct clocksource *clock)
 
 	/* Go back from cycles -> shifted ns */
 	timekeeper.xtime_interval = (u64) interval * clock->mult;
+	timekeeper.xtime_remainder = ntpinterval - timekeeper.xtime_interval;
 	timekeeper.raw_interval =
 		((u64) interval * clock->mult) >> clock->shift;
 
@@ -719,7 +723,8 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
 
 	/* Accumulate error between NTP and clock interval */
 	timekeeper.ntp_error += tick_length << shift;
-	timekeeper.ntp_error -= timekeeper.xtime_interval <<
+	timekeeper.ntp_error -=
+	    (timekeeper.xtime_interval + timekeeper.xtime_remainder) <<
 				(timekeeper.ntp_error_shift + shift);
 
 	return offset;