The patch titled
GTOD: exponential update_wall_time
has been removed from the -mm tree. Its filename was
gtod-exponential-update_wall_time.patch
This patch was dropped because it is obsolete
------------------------------------------------------
Subject: GTOD: exponential update_wall_time
From: John Stultz <johnstul@xxxxxxxxxx>
Accumulate time in update_wall_time() exponentially. This avoids long running
loops seen with the dynticks patch as well as the problematic hang seen on
systems with broken clocksources.
NOTE: this only has relevance on dyntick kernels, so the quality of NTP
updates on jiffies-tick systems is unaffected. (non-dyntick kernels call
update_wall_time() in every timer tick)
Signed-off-by: John Stultz <johnstul@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/timer.c | 28 ++++++++++++++++++++--------
1 files changed, 20 insertions(+), 8 deletions(-)
diff -puN kernel/timer.c~gtod-exponential-update_wall_time kernel/timer.c
--- a/kernel/timer.c~gtod-exponential-update_wall_time
+++ a/kernel/timer.c
@@ -907,6 +907,7 @@ static void clocksource_adjust(struct cl
static void update_wall_time(void)
{
cycle_t offset;
+ int shift = 0;
/* Make sure we're fully resumed: */
if (unlikely(timekeeping_suspended))
@@ -919,28 +920,39 @@ static void update_wall_time(void)
#endif
clock->xtime_nsec += (s64)xtime.tv_nsec << clock->shift;
+ while (offset > clock->cycle_interval << (shift + 1))
+ 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) {
+ if (offset < (clock->cycle_interval << shift)) {
+ shift--;
+ continue;
+ }
+
/* accumulate one interval */
- clock->xtime_nsec += clock->xtime_interval;
- clock->cycle_last += clock->cycle_interval;
- offset -= clock->cycle_interval;
+ clock->xtime_nsec += clock->xtime_interval << shift;
+ clock->cycle_last += clock->cycle_interval << shift;
+ offset -= clock->cycle_interval << shift;
- if (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
+ while (clock->xtime_nsec >= (u64)NSEC_PER_SEC << clock->shift) {
clock->xtime_nsec -= (u64)NSEC_PER_SEC << clock->shift;
xtime.tv_sec++;
second_overflow();
}
/* interpolator bits */
- time_interpolator_update(clock->xtime_interval
- >> clock->shift);
+ time_interpolator_update((clock->xtime_interval
+ >> clock->shift)<<shift);
/* accumulate error between NTP and clock interval */
- clock->error += current_tick_length();
- clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
+ clock->error += current_tick_length() << shift;
+ clock->error -= (clock->xtime_interval
+ << (TICK_LENGTH_SHIFT - clock->shift))<<shift;
+
+ shift--;
}
/* correct the clock when NTP error is too big */
_
Patches currently in -mm which might be from johnstul@xxxxxxxxxx are
origin.patch
gtod-persistent-clock-support-core.patch
gtod-persistent-clock-support-i386.patch
hrtimers-add-state-tracking.patch
hrtimers-clean-up-callback-tracking.patch
hrtimers-move-and-add-documentation.patch
acpi-include-fix.patch
acpi-cleanups-allow-early-access-to-pmtimer.patch
clockevents-core.patch
clockevents-i386-drivers.patch
high-res-timers-core.patch
dynticks-core.patch
dynticks-add-nohz-stats-to-proc-stat.patch
dynticks-i386-support-idle-handler-callbacks.patch
debugging-feature-add-proc-timer_stat.patch
-
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