Re: [PATCH v5 1/7] Revert "sched: Introduce temporaryFAIR_GROUP_SCHED dependency for load-tracking"

[Paul Turner]

On Sun, May 5, 2013 at 6:45 PM, Alex Shi <alex.shi@xxxxxxxxx> wrote:
> Remove CONFIG_FAIR_GROUP_SCHED that covers the runnable info, then
> we can use runnable load variables.
>
> Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx>
> ---
>  include/linux/sched.h |  7 +------
>  kernel/sched/core.c   |  7 +------
>  kernel/sched/fair.c   | 13 ++-----------
>  kernel/sched/sched.h  |  9 +--------
>  4 files changed, 5 insertions(+), 31 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index e692a02..9539597 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1161,12 +1161,7 @@ struct sched_entity {
>         struct cfs_rq           *my_q;
>  #endif
>
> -/*
> - * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
> - * removed when useful for applications beyond shares distribution (e.g.
> - * load-balance).
> - */
> -#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
> +#ifdef CONFIG_SMP
>         /* Per-entity load-tracking */
>         struct sched_avg        avg;
>  #endif
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 67d0465..c8db984 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -1563,12 +1563,7 @@ static void __sched_fork(struct task_struct *p)
>         p->se.vruntime                  = 0;
>         INIT_LIST_HEAD(&p->se.group_node);
>
> -/*
> - * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
> - * removed when useful for applications beyond shares distribution (e.g.
> - * load-balance).
> - */
> -#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
> +#ifdef CONFIG_SMP
>         p->se.avg.runnable_avg_period = 0;
>         p->se.avg.runnable_avg_sum = 0;
>  #endif
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 7a33e59..9c2f726 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -1109,8 +1109,7 @@ static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
>  }
>  #endif /* CONFIG_FAIR_GROUP_SCHED */
>
> -/* Only depends on SMP, FAIR_GROUP_SCHED may be removed when useful in lb */
> -#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED)
> +#ifdef CONFIG_SMP
>  /*
>   * We choose a half-life close to 1 scheduling period.
>   * Note: The tables below are dependent on this value.
> @@ -3394,12 +3393,6 @@ unlock:
>  }
>
>  /*
> - * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
> - * removed when useful for applications beyond shares distribution (e.g.
> - * load-balance).
> - */
> -#ifdef CONFIG_FAIR_GROUP_SCHED
> -/*
>   * Called immediately before a task is migrated to a new cpu; task_cpu(p) and
>   * cfs_rq_of(p) references at time of call are still valid and identify the
>   * previous cpu.  However, the caller only guarantees p->pi_lock is held; no
> @@ -3422,7 +3415,6 @@ migrate_task_rq_fair(struct task_struct *p, int next_cpu)
>                 atomic64_add(se->avg.load_avg_contrib, &cfs_rq->removed_load);
>         }
>  }
> -#endif
>  #endif /* CONFIG_SMP */
>
>  static unsigned long
> @@ -6114,9 +6106,8 @@ const struct sched_class fair_sched_class = {
>
>  #ifdef CONFIG_SMP
>         .select_task_rq         = select_task_rq_fair,
> -#ifdef CONFIG_FAIR_GROUP_SCHED
>         .migrate_task_rq        = migrate_task_rq_fair,
> -#endif
> +
>         .rq_online              = rq_online_fair,
>         .rq_offline             = rq_offline_fair,
>
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index cc03cfd..7f36024f 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -227,12 +227,6 @@ struct cfs_rq {
>  #endif
>
>  #ifdef CONFIG_SMP
> -/*
> - * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
> - * removed when useful for applications beyond shares distribution (e.g.
> - * load-balance).
> - */
> -#ifdef CONFIG_FAIR_GROUP_SCHED
>         /*
>          * CFS Load tracking
>          * Under CFS, load is tracked on a per-entity basis and aggregated up.
> @@ -242,8 +236,7 @@ struct cfs_rq {
>         u64 runnable_load_avg, blocked_load_avg;
>         atomic64_t decay_counter, removed_load;
>         u64 last_decay;
> -#endif /* CONFIG_FAIR_GROUP_SCHED */
> -/* These always depend on CONFIG_FAIR_GROUP_SCHED */

We should perhaps replace this with a comment that these are only
needed to aggregate the point-wise representation in the
FAIR_GROUP_SCHED case.

> +
>  #ifdef CONFIG_FAIR_GROUP_SCHED
>         u32 tg_runnable_contrib;
>         u64 tg_load_contrib;
> --
> 1.7.12
>
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