From ffb7e01c4e654d5c8bf2ce2a4830b826fa1f149e Mon Sep 17 00:00:00 2001 From: Peng Liu Date: Sun, 25 Feb 2024 23:54:53 +0100 Subject: tick/nohz: Remove duplicate between tick_nohz_switch_to_nohz() and tick_setup_sched_timer() The ts->sched_timer initialization work of tick_nohz_switch_to_nohz() is almost the same as that of tick_setup_sched_timer(), so adjust the latter to get it reused by tick_nohz_switch_to_nohz(). This also makes the low resolution mode sched_timer benefit from the tick skew boot option. Signed-off-by: Peng Liu Signed-off-by: Frederic Weisbecker Signed-off-by: Thomas Gleixner Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20240225225508.11587-2-frederic@kernel.org --- kernel/time/hrtimer.c | 2 +- kernel/time/tick-sched.c | 39 ++++++++++++++++++--------------------- kernel/time/tick-sched.h | 2 +- 3 files changed, 20 insertions(+), 23 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 1fd106af747d..95f1f351dcd9 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -747,7 +747,7 @@ static void hrtimer_switch_to_hres(void) base->hres_active = 1; hrtimer_resolution = HIGH_RES_NSEC; - tick_setup_sched_timer(); + tick_setup_sched_timer(NOHZ_MODE_HIGHRES); /* "Retrigger" the interrupt to get things going */ retrigger_next_event(NULL); } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 417bb7f880ca..d4901654148d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1471,9 +1471,6 @@ static inline void tick_nohz_activate(struct tick_sched *ts, int mode) */ static void tick_nohz_switch_to_nohz(void) { - struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); - ktime_t next; - if (!tick_nohz_enabled) return; @@ -1482,16 +1479,9 @@ static void tick_nohz_switch_to_nohz(void) /* * Recycle the hrtimer in 'ts', so we can share the - * hrtimer_forward_now() function with the highres code. + * highres code. */ - hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD); - /* Get the next period */ - next = tick_init_jiffy_update(); - - hrtimer_set_expires(&ts->sched_timer, next); - hrtimer_forward_now(&ts->sched_timer, TICK_NSEC); - tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); - tick_nohz_activate(ts, NOHZ_MODE_LOWRES); + tick_setup_sched_timer(NOHZ_MODE_LOWRES); } static inline void tick_nohz_irq_enter(void) @@ -1570,7 +1560,11 @@ static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer) 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; static int __init skew_tick(char *str) @@ -1583,15 +1577,17 @@ early_param("skew_tick", skew_tick); /** * tick_setup_sched_timer - setup the tick emulation timer + * @mode: tick_nohz_mode to setup for */ -void tick_setup_sched_timer(void) +void tick_setup_sched_timer(int mode) { struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); - ktime_t now = ktime_get(); /* Emulate tick processing via per-CPU hrtimers: */ hrtimer_init(&ts->sched_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD); - ts->sched_timer.function = tick_nohz_highres_handler; + + if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && mode == NOHZ_MODE_HIGHRES) + ts->sched_timer.function = tick_nohz_highres_handler; /* Get the next period (per-CPU) */ hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update()); @@ -1604,13 +1600,14 @@ void tick_setup_sched_timer(void) hrtimer_add_expires_ns(&ts->sched_timer, offset); } - hrtimer_forward(&ts->sched_timer, now, TICK_NSEC); - hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD); - tick_nohz_activate(ts, NOHZ_MODE_HIGHRES); + hrtimer_forward_now(&ts->sched_timer, TICK_NSEC); + if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && mode == NOHZ_MODE_HIGHRES) + hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD); + else + tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); + tick_nohz_activate(ts, mode); } -#endif /* HIGH_RES_TIMERS */ -#if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS void tick_cancel_sched_timer(int cpu) { struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu); @@ -1632,7 +1629,7 @@ void tick_cancel_sched_timer(int cpu) ts->idle_calls = idle_calls; ts->idle_sleeps = idle_sleeps; } -#endif +#endif /* CONFIG_NO_HZ_COMMON || CONFIG_HIGH_RES_TIMERS */ /* * Async notification about clocksource changes diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h index 5ed5a9d41d5a..35808bbb8a47 100644 --- a/kernel/time/tick-sched.h +++ b/kernel/time/tick-sched.h @@ -102,7 +102,7 @@ struct tick_sched { extern struct tick_sched *tick_get_tick_sched(int cpu); -extern void tick_setup_sched_timer(void); +extern void tick_setup_sched_timer(int mode); #if defined CONFIG_NO_HZ_COMMON || defined CONFIG_HIGH_RES_TIMERS extern void tick_cancel_sched_timer(int cpu); #else -- cgit v1.2.3