tick/nohz: Remove duplicate between lowres and highres handlers

tick_nohz_lowres_handler() does the same work as
tick_nohz_highres_handler() plus the clockevent device reprogramming, so
make the former reuse the latter and rename it accordingly.

Signed-off-by: Peng Liu <liupeng17@lenovo.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240225225508.11587-3-frederic@kernel.org

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index d4901654148d1a17b2a416472bf8e566b56fa334..88c992f48126b7af91dbb75eb76f1e41d1f02106 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -255,6 +255,40 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
        update_process_times(user_mode(regs));
        profile_tick(CPU_PROFILING);
 }
+
+/*
+ * We rearm the timer until we get disabled by the idle code.
+ * Called with interrupts disabled.
+ */
+static enum hrtimer_restart tick_nohz_handler(struct hrtimer *timer)
+{
+       struct tick_sched *ts = container_of(timer, struct tick_sched, sched_timer);
+       struct pt_regs *regs = get_irq_regs();
+       ktime_t now = ktime_get();
+
+       tick_sched_do_timer(ts, now);
+
+       /*
+        * Do not call when we are not in IRQ context and have
+        * no valid 'regs' pointer
+        */
+       if (regs)
+               tick_sched_handle(ts, regs);
+       else
+               ts->next_tick = 0;
+
+       /*
+        * In dynticks mode, tick reprogram is deferred:
+        * - to the idle task if in dynticks-idle
+        * - to IRQ exit if in full-dynticks.
+        */
+       if (unlikely(ts->tick_stopped))
+               return HRTIMER_NORESTART;
+
+       hrtimer_forward(timer, now, TICK_NSEC);
+
+       return HRTIMER_RESTART;
+}
 #endif
 
 #ifdef CONFIG_NO_HZ_FULL
@@ -1429,31 +1463,15 @@ void tick_nohz_idle_exit(void)
  * 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.
  */
 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_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)
@@ -1522,48 +1540,6 @@ void tick_irq_enter(void)
        tick_nohz_irq_enter();
 }
 
-/*
- * High resolution timer specific code
- */
-#ifdef CONFIG_HIGH_RES_TIMERS
-/*
- * We rearm the timer until we get disabled by the idle code.
- * Called with interrupts disabled.
- */
-static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer)
-{
-       struct tick_sched *ts =
-               container_of(timer, struct tick_sched, sched_timer);
-       struct pt_regs *regs = get_irq_regs();
-       ktime_t now = ktime_get();
-
-       tick_sched_do_timer(ts, now);
-
-       /*
-        * Do not call when we are not in IRQ context and have
-        * no valid 'regs' pointer
-        */
-       if (regs)
-               tick_sched_handle(ts, regs);
-       else
-               ts->next_tick = 0;
-
-       /*
-        * In dynticks mode, tick reprogram is deferred:
-        * - to the idle task if in dynticks-idle
-        * - to IRQ exit if in full-dynticks.
-        */
-       if (unlikely(ts->tick_stopped))
-               return HRTIMER_NORESTART;
-
-       hrtimer_forward(timer, now, TICK_NSEC);
-
-       return HRTIMER_RESTART;
-}
-#else
-#define tick_nohz_highres_handler NULL
-#endif /* CONFIG_HIGH_RES_TIMERS */
-
 #if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS
 static int sched_skew_tick;
 
@@ -1587,7 +1563,7 @@ void tick_setup_sched_timer(int mode)
        hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
 
        if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && mode == NOHZ_MODE_HIGHRES)
-               ts->sched_timer.function = tick_nohz_highres_handler;
+               ts->sched_timer.function = tick_nohz_handler;
 
        /* Get the next period (per-CPU) */
        hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());