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 <t...@linutronix.de>
---
include/linux/timekeeper_internal.h | 2 ++
kernel/time/timekeeping.c | 4 ++--
2 files changed, 4 insertions(+), 2 deletions(-)
Index: linux-2.6/include/linux/timekeeper_internal.h
===================================================================
--- linux-2.6.orig/include/linux/timekeeper_internal.h
+++ linux-2.6/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 */
Index: linux-2.6/kernel/time/timekeeping.c
===================================================================
--- linux-2.6.orig/kernel/time/timekeeping.c
+++ linux-2.6/kernel/time/timekeeping.c
@@ -99,7 +99,7 @@ static void tk_setup_internals(struct ti
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;
@@ -250,7 +250,7 @@ static void timekeeping_forward_now(stru
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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