From: Peng Liu <[email protected]>
tick_nohz_lowres_handler() does the same work as tick_nohz_highres_handler()
plus the clockevent device reprogramming, so should reuse the latter.
Signed-off-by: Peng Liu <[email protected]>
---
kernel/time/tick-sched.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index cdebb6240efe..63422d6f3aa3 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1383,36 +1383,25 @@ void tick_nohz_idle_exit(void)
local_irq_enable();
}
+static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer);
+
/*
* In low-resolution mode, the tick handler must be implemented directly
* at the clockevent level. hrtimer can't be used instead, because its
* infrastructure actually relies on the tick itself as a backend in
* low-resolution mode (see hrtimer_run_queues()).
*
- * This low-resolution handler still makes use of some hrtimer APIs meanwhile
- * for convenience with expiration calculation and forwarding.
+ * This low-resolution handler still reuse tick_nohz_highres_handler() since
+ * most of the work is independent of the clockevent level.
*/
static void tick_nohz_lowres_handler(struct clock_event_device *dev)
{
struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
- struct pt_regs *regs = get_irq_regs();
- ktime_t now = ktime_get();
dev->next_event = KTIME_MAX;
- tick_sched_do_timer(ts, now);
- tick_sched_handle(ts, regs);
-
- /*
- * In dynticks mode, tick reprogram is deferred:
- * - to the idle task if in dynticks-idle
- * - to IRQ exit if in full-dynticks.
- */
- if (likely(!ts->tick_stopped)) {
- hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
+ if (likely(tick_nohz_highres_handler(&ts->sched_timer) == HRTIMER_RESTART))
tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1);
- }
-
}
static inline void tick_nohz_activate(struct tick_sched *ts, int mode)
@@ -1481,10 +1470,7 @@ void tick_irq_enter(void)
tick_nohz_irq_enter();
}
-/*
- * High resolution timer specific code
- */
-#ifdef CONFIG_HIGH_RES_TIMERS
+#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
/*
* We rearm the timer until we get disabled by the idle code.
* Called with interrupts disabled.
@@ -1519,7 +1505,12 @@ static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer)
return HRTIMER_RESTART;
}
+#endif
+/*
+ * High resolution timer specific code
+ */
+#ifdef CONFIG_HIGH_RES_TIMERS
static int sched_skew_tick;
static int __init skew_tick(char *str)
--
2.34.1