Messages in this thread Patch in this message | | | From | Peng Liu <> | Subject | [PATCH v3 1/2] tick/nohz: Remove duplicate between tick_nohz_switch_to_nohz() and tick_setup_sched_timer() | Date | Wed, 29 Nov 2023 18:35:18 +0800 |
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From: Peng Liu <liupeng17@lenovo.com>
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 low-res mode sched_timer benefit from the tick skew boot option.
Signed-off-by: Peng Liu <liupeng17@lenovo.com> --- Changes in v3: - Remove the first``#ifdef CONFIG_HIGH_RES_TIMERS'' in tick_setup_sched_timer() in patch 2/2 - Add comment on sched_skew_tick introduced to low-res mode tick_sched setup - Replace hrtimer_forward() with hrtimer_forward_now() in tick_setup_sched_timer() - Remove the sedond ``#ifdef CONFIG_HIGH_RES_TIMERS'' in tick_setup_sched_timer() - Move tick_nohz_highres_handler() ahead to avoid additional declaration Changes in v2: - Fix build warning: Function parameter or member 'mode' not described in 'tick_setup_sched_timer' - Fix build error: use of undeclared identifier 'tick_nohz_highres_handler' - Fix build error: use of undeclared identifier 'sched_skew_tick' --- kernel/time/hrtimer.c | 2 +- kernel/time/tick-sched.c | 38 +++++++++++++++++--------------------- kernel/time/tick-sched.h | 2 +- 3 files changed, 19 insertions(+), 23 deletions(-)
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 760793998cdd..355b5a957f7f 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -746,7 +746,7 @@ 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 be77b021e5d6..d25039f07838 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1430,9 +1430,6 @@ 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; @@ -1441,16 +1438,9 @@ 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) @@ -1529,7 +1519,9 @@ static enum hrtimer_restart tick_nohz_highres_handler(struct hrtimer *timer) return HRTIMER_RESTART; } +#endif /* 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) @@ -1542,15 +1534,18 @@ 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; +#ifdef CONFIG_HIGH_RES_TIMERS + if (mode == NOHZ_MODE_HIGHRES) + ts->sched_timer.function = tick_nohz_highres_handler; +#endif /* Get the next period (per-CPU) */ hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update()); @@ -1563,13 +1558,14 @@ 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 (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); @@ -1581,7 +1577,7 @@ void tick_cancel_sched_timer(int cpu) memset(ts, 0, sizeof(*ts)); } -#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 -- 2.34.1
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