> 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 Signed-off-by: Steven Rostedt --- 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 majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/