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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-16 12:19:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-16 12:19:18 -0800
commit558e8e27e73f53f8a512485be538b07115fe5f3c (patch)
tree7a2f37e7a575537db37ee1238471bbb4f3e0a488
parent4695daefba8df8a11fa0b0edd595eedae9ea59ae (diff)
downloadlinux-stericsson-558e8e27e73f53f8a512485be538b07115fe5f3c.tar.gz
Revert "nohz: Fix collision between tick and other hrtimers"
This reverts commit 24b91e360ef521a2808771633d76ebc68bd5604b and commit 7bdb59f1ad47 ("tick/nohz: Fix possible missing clock reprog after tick soft restart") that depends on it, Pavel reports that it causes occasional boot hangs for him that seem to depend on just how the machine was booted. In particular, his machine hangs at around the PCI fixups of the EHCI USB host controller, but only hangs from cold boot, not from a warm boot. Thomas Gleixner suspecs it's a CPU hotplug interaction, particularly since Pavel also saw suspend/resume issues that seem to be related. We're reverting for now while trying to figure out the root cause. Reported-bisected-and-tested-by: Pavel Machek <pavel@ucw.cz> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org # reverted commits were marked for stable Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/time/tick-sched.c14
-rw-r--r--kernel/time/tick-sched.h2
2 files changed, 2 insertions, 14 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index fc6f740d0277..2c115fdab397 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -725,11 +725,6 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
*/
if (delta == 0) {
tick_nohz_restart(ts, now);
- /*
- * Make sure next tick stop doesn't get fooled by past
- * clock deadline
- */
- ts->next_tick = 0;
goto out;
}
}
@@ -772,7 +767,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
tick = expires;
/* Skip reprogram of event if its not changed */
- if (ts->tick_stopped && (expires == ts->next_tick))
+ if (ts->tick_stopped && (expires == dev->next_event))
goto out;
/*
@@ -792,8 +787,6 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
trace_tick_stop(1, TICK_DEP_MASK_NONE);
}
- ts->next_tick = tick;
-
/*
* If the expiration time == KTIME_MAX, then we simply stop
* the tick timer.
@@ -809,10 +802,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
else
tick_program_event(tick, 1);
out:
- /*
- * Update the estimated sleep length until the next timer
- * (not only the tick).
- */
+ /* Update the estimated sleep length */
ts->sleep_length = ktime_sub(dev->next_event, now);
return tick;
}
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
index 075444e3d48e..bf38226e5c17 100644
--- a/kernel/time/tick-sched.h
+++ b/kernel/time/tick-sched.h
@@ -27,7 +27,6 @@ enum tick_nohz_mode {
* timer is modified for nohz sleeps. This is necessary
* to resume the tick timer operation in the timeline
* when the CPU returns from nohz sleep.
- * @next_tick: Next tick to be fired when in dynticks mode.
* @tick_stopped: Indicator that the idle tick has been stopped
* @idle_jiffies: jiffies at the entry to idle for idle time accounting
* @idle_calls: Total number of idle calls
@@ -45,7 +44,6 @@ struct tick_sched {
unsigned long check_clocks;
enum tick_nohz_mode nohz_mode;
ktime_t last_tick;
- ktime_t next_tick;
int inidle;
int tick_stopped;
unsigned long idle_jiffies;