> void update_wall_time(void)
> {
> - cycle_t offset;
> + cycle_t cycle_now, offset;
>
> /* Make sure we're fully resumed: */
> if (unlikely(timekeeping_suspended))
> return;
>
> #ifdef CONFIG_GENERIC_TIME
> - offset = (clocksource_read(clock) - clock->cycle_last) & clock->mask;
> + cycle_now = clocksource_read(clock);
> #else
> - offset = clock->cycle_interval;
> + cycle_now = clock->cycle_last + clock->cycle_interval;
> #endif
> + offset = (cycle_now - clock->cycle_last) & clock->mask;
It seems this offset addition was to merge against the colliding
xtime_cache changes in mainline. However, I don't think its quite right,
and might be causing incorrect time() or vtime() results if NO_HZ is
enabled.
> + clocksource_accumulate(clock, cycle_now);
> +
> clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
>
> /* normally this loop will run just once, however in the
> * case of lost or late ticks, it will accumulate correctly.
> */
> - while (offset >= clock->cycle_interval) {
> + while (clock->cycle_accumulated >= clock->cycle_interval) {
> /* accumulate one interval */
> clock->xtime_nsec += clock->xtime_interval;
> - clock->cycle_last += clock->cycle_interval;
> - offset -= clock->cycle_interval;
> + clock->cycle_accumulated -= clock->cycle_interval;
>
> if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
> clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
> @@ -482,7 +485,7 @@ void update_wall_time(void)
> }
>
> /* correct the clock when NTP error is too big */
> - clocksource_adjust(offset);
> + clocksource_adjust(clock->cycle_accumulated);
I suspect the following is needed, but haven't been able to test it yet.
Fixup merge between xtime_cache and timekeeping starvation fix.
Signed-off-by: John Stultz <[EMAIL PROTECTED]>
Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]>
---
kernel/time/timekeeping.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
Index: linux-mcount.git/kernel/time/timekeeping.c
===================================================================
--- linux-mcount.git.orig/kernel/time/timekeeping.c 2008-01-17
20:33:37.000000000 -0500
+++ linux-mcount.git/kernel/time/timekeeping.c 2008-01-17 20:33:39.000000000
-0500
@@ -449,7 +449,7 @@ static void clocksource_adjust(s64 offse
*/
void update_wall_time(void)
{
- cycle_t cycle_now, offset;
+ cycle_t cycle_now;
/* Make sure we're fully resumed: */
if (unlikely(timekeeping_suspended))
@@ -460,7 +460,6 @@ void update_wall_time(void)
#else
cycle_now = clock->cycle_last + clock->cycle_interval;
#endif
- offset = (cycle_now - clock->cycle_last) & clock->mask;
clocksource_accumulate(clock, cycle_now);
clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
@@ -491,7 +490,7 @@ void update_wall_time(void)
xtime.tv_nsec = (s64)clock->xtime_nsec >> clock->shift;
clock->xtime_nsec -= (s64)xtime.tv_nsec << clock->shift;
- update_xtime_cache(cyc2ns(clock, offset));
+ update_xtime_cache(cyc2ns(clock, clock->cycle_accumulated));
/* check to see if there is a new clocksource to use */
change_clocksource();
--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
