From: Peng Liu <[email protected]>
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().
Signed-off-by: Peng Liu <[email protected]>
---
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 | 37 ++++++++++++++++++-------------------
kernel/time/tick-sched.h | 2 +-
3 files changed, 20 insertions(+), 21 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..96fcf5cb1b49 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 +1534,19 @@ 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());
@@ -1564,12 +1560,15 @@ void tick_setup_sched_timer(void)
}
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);
+#ifdef CONFIG_HIGH_RES_TIMERS
+ if (mode == NOHZ_MODE_HIGHRES)
+ hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
+ else
+#endif
+ 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 +1580,7 @@ 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
On Tue, Nov 28, 2023 at 05:23:54PM +0800, Peng Liu wrote:
> @@ -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
tick-sched.c is only ever built if CONFIG_TICK_ONESHOT=y and
CONFIG_TICK_ONESHOT is basically (CONFIG_NO_HZ_COMMON || CONFIG_HIGH_RES_TIMERS)
So probably the above is not needed and if you like you can even send
a subsequent patch removing such ifdefs within this file :-)
> static int sched_skew_tick;
>
> static int __init skew_tick(char *str)
> @@ -1542,15 +1534,19 @@ 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
That ifdef could simply be removed.
>
> /* Get the next period (per-CPU) */
> hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
> @@ -1564,12 +1560,15 @@ void tick_setup_sched_timer(void)
> }
That invisible part above is the skew_tick thing, which can probably work
on low-res mode so why not but please tell about that in the changelog.
>
> hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
Looks like this can be hrtimer_forward_now() and you can remove the now.
> - hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
> - tick_nohz_activate(ts, NOHZ_MODE_HIGHRES);
> +#ifdef CONFIG_HIGH_RES_TIMERS
> + if (mode == NOHZ_MODE_HIGHRES)
> + hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
> + else
> +#endif
And probably that ifdef could simply be turned to
IS_ENABLED(CONFIG_HIGH_RES_TIMERS).
Thanks!
On 2023/11/29 0:56, Frederic Weisbecker wrote:
> On Tue, Nov 28, 2023 at 05:23:54PM +0800, Peng Liu wrote:
>> @@ -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
> tick-sched.c is only ever built if CONFIG_TICK_ONESHOT=y and
> CONFIG_TICK_ONESHOT is basically (CONFIG_NO_HZ_COMMON || CONFIG_HIGH_RES_TIMERS)
>
> So probably the above is not needed and if you like you can even send
> a subsequent patch removing such ifdefs within this file :-)
>
>> static int sched_skew_tick;
>>
>> static int __init skew_tick(char *str)
>> @@ -1542,15 +1534,19 @@ 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
> That ifdef could simply be removed.
>
>>
>> /* Get the next period (per-CPU) */
>> hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
>> @@ -1564,12 +1560,15 @@ void tick_setup_sched_timer(void)
>> }
> That invisible part above is the skew_tick thing, which can probably work
> on low-res mode so why not but please tell about that in the changelog.
>
>>
>> hrtimer_forward(&ts->sched_timer, now, TICK_NSEC);
> Looks like this can be hrtimer_forward_now() and you can remove the now.
>
>> - hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
>> - tick_nohz_activate(ts, NOHZ_MODE_HIGHRES);
>> +#ifdef CONFIG_HIGH_RES_TIMERS
>> + if (mode == NOHZ_MODE_HIGHRES)
>> + hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD);
>> + else
>> +#endif
> And probably that ifdef could simply be turned to
> IS_ENABLED(CONFIG_HIGH_RES_TIMERS).
>
> Thanks!
Thanks for comments. I will update my patches, and also try removing
(CONFIG_NO_HZ_COMMON || CONFIG_HIGH_RES_TIMERS) in another patch.
Regards,
Peng