The patch titled
nohz: fix wrong event handler after online an offlined cpu
has been added to the -mm tree. Its filename is
nohz-fix-wrong-event-handler-after-online-an-offlined-cpu.patch
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Subject: nohz: fix wrong event handler after online an offlined cpu
From: Miao Xie <miaox@xxxxxxxxxxxxxx>
On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after
I made an offlined cpu online, I found this cpu's event handler was
tick_handle_periodic, not tick_nohz_handler.
After debuging, I found this bug was caused by the wrong tick mode. the
tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline.
This patch fixes this bug.
Signed-off-by: Miao Xie <miaox@xxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/tick.h | 5 ++++-
kernel/time/tick-sched.c | 6 +++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff -puN include/linux/tick.h~nohz-fix-wrong-event-handler-after-online-an-offlined-cpu include/linux/tick.h
--- a/include/linux/tick.h~nohz-fix-wrong-event-handler-after-online-an-offlined-cpu
+++ a/include/linux/tick.h
@@ -74,10 +74,13 @@ extern struct tick_device *tick_get_devi
extern int tick_init_highres(void);
extern int tick_program_event(ktime_t expires, int force);
extern void tick_setup_sched_timer(void);
+# endif
+
+# if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
extern void tick_cancel_sched_timer(int cpu);
# else
static inline void tick_cancel_sched_timer(int cpu) { }
-# endif /* HIGHRES */
+# endif
# ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
extern struct tick_device *tick_get_broadcast_device(void);
diff -puN kernel/time/tick-sched.c~nohz-fix-wrong-event-handler-after-online-an-offlined-cpu kernel/time/tick-sched.c
--- a/kernel/time/tick-sched.c~nohz-fix-wrong-event-handler-after-online-an-offlined-cpu
+++ a/kernel/time/tick-sched.c
@@ -659,17 +659,21 @@ void tick_setup_sched_timer(void)
ts->nohz_mode = NOHZ_MODE_HIGHRES;
#endif
}
+#endif /* HIGH_RES_TIMERS */
+#if defined CONFIG_NO_HZ || defined CONFIG_HIGH_RES_TIMERS
void tick_cancel_sched_timer(int cpu)
{
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+# ifdef CONFIG_HIGH_RES_TIMERS
if (ts->sched_timer.base)
hrtimer_cancel(&ts->sched_timer);
+# endif
ts->nohz_mode = NOHZ_MODE_INACTIVE;
}
-#endif /* HIGH_RES_TIMERS */
+#endif
/**
* Async notification about clocksource changes
_
Patches currently in -mm which might be from miaox@xxxxxxxxxxxxxx are
nohz-fix-wrong-event-handler-after-online-an-offlined-cpu.patch
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