On 01/28/21 18:31, Valentin Schneider wrote:
> Comparing capacity extrema of local and source sched_group's doesn't make
> much sense when at the day of the day the imbalance will be pulled by a
> known env->dst_cpu, whose capacity can be anywhere within the local group's
> capacity extrema.
>
> Replace group_smaller_{min, max}_cpu_capacity() with comparisons of the
> source group's min/max capacity and the destination CPU's capacity.
>
> Signed-off-by: Valentin Schneider <[email protected]>
> ---
Reviewed-by: Qais Yousef <[email protected]>
Thanks
--
Qais Yousef
> kernel/sched/fair.c | 31 +++----------------------------
> 1 file changed, 3 insertions(+), 28 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 58ce0b22fcb0..0959a770ecc0 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -8352,26 +8352,6 @@ group_is_overloaded(unsigned int imbalance_pct, struct
> sg_lb_stats *sgs)
> return false;
> }
>
> -/*
> - * group_smaller_min_cpu_capacity: Returns true if sched_group sg has smaller
> - * per-CPU capacity than sched_group ref.
> - */
> -static inline bool
> -group_smaller_min_cpu_capacity(struct sched_group *sg, struct sched_group
> *ref)
> -{
> - return capacity_greater(ref->sgc->min_capacity, sg->sgc->min_capacity);
> -}
> -
> -/*
> - * group_smaller_max_cpu_capacity: Returns true if sched_group sg has smaller
> - * per-CPU capacity_orig than sched_group ref.
> - */
> -static inline bool
> -group_smaller_max_cpu_capacity(struct sched_group *sg, struct sched_group
> *ref)
> -{
> - return capacity_greater(ref->sgc->max_capacity, sg->sgc->max_capacity);
> -}
> -
> static inline enum
> group_type group_classify(unsigned int imbalance_pct,
> struct sched_group *group,
> @@ -8523,15 +8503,10 @@ static bool update_sd_pick_busiest(struct lb_env *env,
> if (!sgs->sum_h_nr_running)
> return false;
>
> - /*
> - * Don't try to pull misfit tasks we can't help.
> - * We can use max_capacity here as reduction in capacity on some
> - * CPUs in the group should either be possible to resolve
> - * internally or be covered by avg_load imbalance (eventually).
> - */
> + /* Don't try to pull misfit tasks we can't help */
> if (static_branch_unlikely(&sched_asym_cpucapacity) &&
> sgs->group_type == group_misfit_task &&
> - (!group_smaller_max_cpu_capacity(sg, sds->local) ||
> + (!capacity_greater(capacity_of(env->dst_cpu),
> sg->sgc->max_capacity) ||
> sds->local_stat.group_type != group_has_spare))
> return false;
>
> @@ -8615,7 +8590,7 @@ static bool update_sd_pick_busiest(struct lb_env *env,
> */
> if (sd_has_asym_cpucapacity(env->sd) &&
> (sgs->group_type <= group_fully_busy) &&
> - (group_smaller_min_cpu_capacity(sds->local, sg)))
> + (capacity_greater(sg->sgc->min_capacity,
> capacity_of(env->dst_cpu))))
> return false;
>
> return true;
> --
> 2.27.0
>
