Commit-ID: 14a3b6abe98c8f53a13522610c257accef7321df
Gitweb: http://git.kernel.org/tip/14a3b6abe98c8f53a13522610c257accef7321df
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Thu, 21 Feb 2013 22:51:38 +0000
Committer: John Stultz <john.stultz@xxxxxxxxxx>
CommitDate: Thu, 4 Apr 2013 13:18:31 -0700
timekeeping: Store cycle_last value in timekeeper struct as well
For implementing a shadow timekeeper and a split calculation/update
region we need to store the cycle_last value in the timekeeper and
update the value in the clocksource struct only in the update region.
Add the extra storage to the timekeeper.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
---
include/linux/timekeeper_internal.h | 2 ++
kernel/time/timekeeping.c | 4 ++--
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index a151bd7..c1825eb 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -20,6 +20,8 @@ struct timekeeper {
u32 shift;
/* Number of clock cycles in one NTP interval. */
cycle_t cycle_interval;
+ /* Last cycle value (also stored in clock->cycle_last) */
+ cycle_t cycle_last;
/* Number of clock shifted nano seconds in one NTP interval. */
u64 xtime_interval;
/* shifted nano seconds left over when rounding cycle_interval */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index f93f60c..4c276b2 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -101,7 +101,7 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
old_clock = tk->clock;
tk->clock = clock;
- clock->cycle_last = clock->read(clock);
+ tk->cycle_last = clock->cycle_last = clock->read(clock);
/* Do the ns -> cycle conversion first, using original mult */
tmp = NTP_INTERVAL_LENGTH;
@@ -266,7 +266,7 @@ static void timekeeping_forward_now(struct timekeeper *tk)
clock = tk->clock;
cycle_now = clock->read(clock);
cycle_delta = (cycle_now - clock->cycle_last) & clock->mask;
- clock->cycle_last = cycle_now;
+ tk->cycle_last = clock->cycle_last = cycle_now;
tk->xtime_nsec += cycle_delta * tk->mult;
--
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