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SubjectRe: [PATCH v2 1/4] sched/uclamp: Make uclamp_util_*() helpers use and return UL values
On Tue, 3 Dec 2019 at 17:02, Valentin Schneider
<valentin.schneider@arm.com> wrote:
>
> Vincent pointed out recently that the canonical type for utilization
> values is 'unsigned long'. Internally uclamp uses 'unsigned int' values for
> cache optimization, but this doesn't have to be exported to its users.
>
> Make the uclamp helpers that deal with utilization use and return unsigned
> long values.
>
> Reviewed-by: Quentin Perret <qperret@google.com>
> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
> ---
> kernel/sched/sched.h | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 280a3c735935..f1d035e5df7e 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -2303,15 +2303,15 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
> unsigned int uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);

Why not changing uclamp_eff_value to return unsigned long too ? The
returned value represents a utilization to be compared with other
utilization value

>
> static __always_inline
> -unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
> - struct task_struct *p)
> +unsigned long uclamp_util_with(struct rq *rq, unsigned long util,
> + struct task_struct *p)
> {
> - unsigned int min_util = READ_ONCE(rq->uclamp[UCLAMP_MIN].value);
> - unsigned int max_util = READ_ONCE(rq->uclamp[UCLAMP_MAX].value);
> + unsigned long min_util = READ_ONCE(rq->uclamp[UCLAMP_MIN].value);
> + unsigned long max_util = READ_ONCE(rq->uclamp[UCLAMP_MAX].value);
>
> if (p) {
> - min_util = max(min_util, uclamp_eff_value(p, UCLAMP_MIN));
> - max_util = max(max_util, uclamp_eff_value(p, UCLAMP_MAX));
> + min_util = max_t(unsigned long, min_util, uclamp_eff_value(p, UCLAMP_MIN));

As mentioned above, uclamp_eff_value should return an unsigned long

> + max_util = max_t(unsigned long, max_util, uclamp_eff_value(p, UCLAMP_MAX));
> }
>
> /*
> @@ -2325,17 +2325,17 @@ unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
> return clamp(util, min_util, max_util);
> }
>
> -static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
> +static inline unsigned long uclamp_util(struct rq *rq, unsigned long util)
> {
> return uclamp_util_with(rq, util, NULL);
> }
> #else /* CONFIG_UCLAMP_TASK */
> -static inline unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
> - struct task_struct *p)
> +static inline unsigned long uclamp_util_with(struct rq *rq, unsigned long util,
> + struct task_struct *p)
> {
> return util;
> }
> -static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
> +static inline unsigned long uclamp_util(struct rq *rq, unsigned long util)
> {
> return util;
> }
> --
> 2.24.0
>

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