Re: [PATCH v9 07/10] time: hrtimer: Introduce hrtimer_next_event_without()

Frederic Weisbecker
2018-04-07T14:46:43Z

On Wed, Apr 04, 2018 at 10:45:39AM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> The next set of changes will need to compute the time to the next
> hrtimer event over all hrtimers except for the scheduler tick one.
>
> To that end introduce a new helper function,
> hrtimer_next_event_without(), for computing the time until the next
> hrtimer event over all timers except for one and modify the underlying
> code in __hrtimer_next_event_base() to prepare it for being called by
> that new function.
>
> No intentional changes in functionality.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>
> v8 -> v9:
> * Make fewer changes to the existing code.
> * Add a new helper function for the handling of the use case at hand.
>
> ---
> include/linux/hrtimer.h | 1
> kernel/time/hrtimer.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++--
> 2 files changed, 54 insertions(+), 2 deletions(-)
>
> Index: linux-pm/include/linux/hrtimer.h
> ===================================================================
> --- linux-pm.orig/include/linux/hrtimer.h
> +++ linux-pm/include/linux/hrtimer.h
> @@ -426,6 +426,7 @@ static inline ktime_t hrtimer_get_remain
> }
>
> extern u64 hrtimer_get_next_event(void);
> +extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
>
> extern bool hrtimer_active(const struct hrtimer *timer);
>
> Index: linux-pm/kernel/time/hrtimer.c
> ===================================================================
> --- linux-pm.orig/kernel/time/hrtimer.c
> +++ linux-pm/kernel/time/hrtimer.c
> @@ -490,6 +490,7 @@ __next_base(struct hrtimer_cpu_base *cpu
> while ((base = __next_base((cpu_base), &(active))))
>
> static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
> + const struct hrtimer *exclude,
> unsigned int active,
> ktime_t expires_next)
> {
> @@ -502,9 +503,24 @@ static ktime_t __hrtimer_next_event_base
>
> next = timerqueue_getnext(&base->active);
> timer = container_of(next, struct hrtimer, node);
> + if (timer == exclude) {
> + /* Get to the next timer in the queue. */
> + struct rb_node *rbn = rb_next(&next->node);
> +
> + next = rb_entry_safe(rbn, struct timerqueue_node, node);
> + if (!next)
> + continue;

Minor cosmectic detail again, timerqueue_iterate_next() would do the job and
avoid browsing timerqueue details.

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

Thanks.