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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 <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/20240225225508.11587-2-frederic@kernel.org
This commit is contained in:
Peng Liu 2024-02-25 23:54:53 +01:00 committed by Thomas Gleixner
parent 56c2cb1012
commit ffb7e01c4e
3 changed files with 20 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/time/hrtimer.c
View File

@ -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);
}

39
kernel/time/tick-sched.c
View File

@ -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

2
kernel/time/tick-sched.h
View File

@ -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