Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull NOHZ fix from Ingo Molnar:
"This fixes an old NOHZ race where we incorrectly calculate the next
timer interrupt in certain circumstances where hrtimers are pending,
that can cause hard to reproduce stalled-values artifacts in
/proc/stat"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
nohz: Fix collision between tick and other hrtimers
+9
-2
+7
-2
kernel/time/tick-sched.c
+7
-2
kernel/time/tick-sched.c
···
767
767
tick = expires;
768
768
769
769
/* Skip reprogram of event if its not changed */
770
-
if (ts->tick_stopped && (expires == dev->next_event))
770
+
if (ts->tick_stopped && (expires == ts->next_tick))
771
771
goto out;
772
772
773
773
/*
···
787
787
trace_tick_stop(1, TICK_DEP_MASK_NONE);
788
788
}
789
789
790
+
ts->next_tick = tick;
791
+
790
792
/*
791
793
* If the expiration time == KTIME_MAX, then we simply stop
792
794
* the tick timer.
···
804
802
else
805
803
tick_program_event(tick, 1);
806
804
out:
807
-
/* Update the estimated sleep length */
805
+
/*
806
+
* Update the estimated sleep length until the next timer
807
+
* (not only the tick).
808
+
*/
808
809
ts->sleep_length = ktime_sub(dev->next_event, now);
809
810
return tick;
810
811
}
+2
kernel/time/tick-sched.h
+2
kernel/time/tick-sched.h
···
27
27
* timer is modified for nohz sleeps. This is necessary
28
28
* to resume the tick timer operation in the timeline
29
29
* when the CPU returns from nohz sleep.
30
+
* @next_tick: Next tick to be fired when in dynticks mode.
30
31
* @tick_stopped: Indicator that the idle tick has been stopped
31
32
* @idle_jiffies: jiffies at the entry to idle for idle time accounting
32
33
* @idle_calls: Total number of idle calls
···
45
44
unsigned long check_clocks;
46
45
enum tick_nohz_mode nohz_mode;
47
46
ktime_t last_tick;
47
+
ktime_t next_tick;
48
48
int inidle;
49
49
int tick_stopped;
50
50
unsigned long idle_jiffies;