Re: [RFC tg_shares_up improvements - v1 01/12] sched: rewrite tg_shares_up

Bharata B Rao
2010-10-21T08:08:57Z

On Fri, Oct 15, 2010 at 09:43:50PM -0700, pjt@google.com wrote:
> From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> --- kernel/sched_fair.c.orig
> +++ kernel/sched_fair.c
> @@ -417,7 +417,6 @@ int sched_proc_update_handler(struct ctl
> WRT_SYSCTL(sched_min_granularity);
> WRT_SYSCTL(sched_latency);
> WRT_SYSCTL(sched_wakeup_granularity);
> - WRT_SYSCTL(sched_shares_ratelimit);
> #undef WRT_SYSCTL
>
> return 0;
> @@ -633,7 +632,6 @@ account_entity_enqueue(struct cfs_rq *cf
> list_add(&se->group_node, &cfs_rq->tasks);
> }
> cfs_rq->nr_running++;
> - se->on_rq = 1;
> }
>
> static void
> @@ -647,9 +645,89 @@ account_entity_dequeue(struct cfs_rq *cf
> list_del_init(&se->group_node);
> }
> cfs_rq->nr_running--;
> - se->on_rq = 0;
> }
>
<snip>
> @@ -771,7 +849,9 @@ enqueue_entity(struct cfs_rq *cfs_rq, st
> * Update run-time statistics of the 'current'.
> */
> update_curr(cfs_rq);
> + update_cfs_load(cfs_rq);
> account_entity_enqueue(cfs_rq, se);
> + update_cfs_shares(cfs_rq_of(se));
>
> if (flags & ENQUEUE_WAKEUP) {
> place_entity(cfs_rq, se, 0);
> @@ -782,6 +862,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, st
> check_spread(cfs_rq, se);
> if (se != cfs_rq->curr)
> __enqueue_entity(cfs_rq, se);
> + se->on_rq = 1;
> }
>
> static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
> @@ -825,8 +906,11 @@ dequeue_entity(struct cfs_rq *cfs_rq, st
>
> if (se != cfs_rq->curr)
> __dequeue_entity(cfs_rq, se);
> + se->on_rq = 0;

Since setting and un-setting of se->on_rq is completely handled within
sched_fair.c, we can remove the redundant setting and un-setting of
se->on_rq from sched.c:[en]dequeue_task. Even w/o this patch, they were
redundant I suppose.

Regards,
Bharata.