From f4e26b120b9de84cb627bc7361ba43cfdc51341f Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Thu, 4 Oct 2012 13:18:32 +0200 Subject: sched: Introduce temporary FAIR_GROUP_SCHED dependency for load-tracking While per-entity load-tracking is generally useful, beyond computing shares distribution, e.g. runnable based load-balance (in progress), governors, power-management, etc. These facilities are not yet consumers of this data. This may be trivially reverted when the information is required; but avoid paying the overhead for calculations we will not use until then. Signed-off-by: Paul Turner Reviewed-by: Ben Segall Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120823141507.422162369@google.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 7 ++++++- kernel/sched/fair.c | 13 +++++++++++-- kernel/sched/sched.h | 9 ++++++++- 3 files changed, 25 insertions(+), 4 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f26860074ef..5dae0d252ff 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1526,7 +1526,12 @@ static void __sched_fork(struct task_struct *p) p->se.vruntime = 0; INIT_LIST_HEAD(&p->se.group_node); -#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). + */ +#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED) 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 6ecf455fd95..3e6a3531fa9 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -882,7 +882,8 @@ static inline void update_cfs_shares(struct cfs_rq *cfs_rq) } #endif /* CONFIG_FAIR_GROUP_SCHED */ -#ifdef CONFIG_SMP +/* Only depends on SMP, FAIR_GROUP_SCHED may be removed when useful in lb */ +#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED) /* * We choose a half-life close to 1 scheduling period. * Note: The tables below are dependent on this value. @@ -3173,6 +3174,12 @@ unlock: return new_cpu; } +/* + * 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 @@ -3196,6 +3203,7 @@ 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 @@ -5773,8 +5781,9 @@ 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 0a75a430ca7..5eca173b563 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -225,6 +225,12 @@ 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. @@ -234,7 +240,8 @@ 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 */ #ifdef CONFIG_FAIR_GROUP_SCHED u32 tg_runnable_contrib; u64 tg_load_contrib; -- cgit v1.2.3