Messages in this thread Patch in this message | | | Date | Tue, 12 Oct 2010 13:22:47 +0530 | From | Bharata B Rao <> | Subject | [PATCH v3 4/7] sched: unthrottle cfs_rq(s) who ran out of quota at period refresh |
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sched: unthrottle cfs_rq(s) who ran out of quota at period refresh
From: Paul Turner <pjt@google.com>
At the start of a new period there are several actions we must take: - Refresh global bandwidth pool - Unthrottle entities who ran out of quota as refreshed bandwidth permits
Unthrottled entities have the cfs_rq->throttled flag set and are re-enqueued into the cfs entity hierarchy.
sched_rt_period_mask() is refactored slightly into sched_bw_period_mask() since it is now shared by both cfs and rt bandwidth period timers.
The !CONFIG_RT_GROUP_SCHED && CONFIG_SMP case has been collapsed to use rd->span instead of cpu_online_mask since I think that was incorrect before (don't want to hit cpu's outside of your root_domain for RT bandwidth).
Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Nikhil Rao <ncrao@google.com> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> --- kernel/sched.c | 16 ++++++++++++ kernel/sched_fair.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++++- kernel/sched_rt.c | 19 -------------- 3 files changed, 84 insertions(+), 19 deletions(-)
--- a/kernel/sched.c +++ b/kernel/sched.c @@ -1565,6 +1565,8 @@ static int tg_nop(struct task_group *tg, } #endif +static inline const struct cpumask *sched_bw_period_mask(void); + #ifdef CONFIG_SMP /* Used instead of source_load when we know the type == 0 */ static unsigned long weighted_cpuload(const int cpu) @@ -1933,6 +1935,18 @@ static inline void __set_task_cpu(struct static const struct sched_class rt_sched_class; +#ifdef CONFIG_SMP +static inline const struct cpumask *sched_bw_period_mask(void) +{ + return cpu_rq(smp_processor_id())->rd->span; +} +#else +static inline const struct cpumask *sched_bw_period_mask(void) +{ + return cpu_online_mask; +} +#endif + #ifdef CONFIG_CFS_BANDWIDTH /* * default period for cfs group bandwidth. @@ -8937,6 +8951,8 @@ static int tg_set_cfs_bandwidth(struct t raw_spin_lock_irq(&rq->lock); init_cfs_rq_quota(cfs_rq); + if (cfs_rq_throttled(cfs_rq)) + unthrottle_cfs_rq(cfs_rq); raw_spin_unlock_irq(&rq->lock); } mutex_unlock(&mutex); --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -268,6 +268,13 @@ find_matching_se(struct sched_entity **s #endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_CFS_BANDWIDTH +static inline +struct cfs_rq *cfs_bandwidth_cfs_rq(struct cfs_bandwidth *cfs_b, int cpu) +{ + return container_of(cfs_b, struct task_group, + cfs_bandwidth)->cfs_rq[cpu]; +} + static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) { return &tg->cfs_bandwidth; @@ -1219,6 +1226,29 @@ out_throttled: cfs_rq->throttled = 1; } +static void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) +{ + struct sched_entity *se; + struct rq *rq = rq_of(cfs_rq); + + se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; + + cfs_rq->throttled = 0; + for_each_sched_entity(se) { + if (se->on_rq) + break; + + cfs_rq = cfs_rq_of(se); + enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); + if (cfs_rq_throttled(cfs_rq)) + break; + } + + /* determine whether we need to wake up potentally idle cpu */ + if (rq->curr == rq->idle && rq->cfs.nr_running) + resched_task(rq->curr); +} + static void account_cfs_rq_quota(struct cfs_rq *cfs_rq, unsigned long delta_exec) { @@ -1241,8 +1271,44 @@ static void account_cfs_rq_quota(struct static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) { - return 1; + int i, idle = 1; + u64 delta; + const struct cpumask *span; + + if (cfs_b->quota == RUNTIME_INF) + return 1; + + /* reset group quota */ + raw_spin_lock(&cfs_b->lock); + cfs_b->runtime = cfs_b->quota; + raw_spin_unlock(&cfs_b->lock); + + span = sched_bw_period_mask(); + for_each_cpu(i, span) { + struct rq *rq = cpu_rq(i); + struct cfs_rq *cfs_rq = cfs_bandwidth_cfs_rq(cfs_b, i); + + if (cfs_rq->nr_running) + idle = 0; + + if (!cfs_rq_throttled(cfs_rq)) + continue; + + delta = tg_request_cfs_quota(cfs_rq->tg); + + if (delta) { + raw_spin_lock(&rq->lock); + cfs_rq->quota_assigned += delta; + + if (cfs_rq->quota_used < cfs_rq->quota_assigned) + unthrottle_cfs_rq(cfs_rq); + raw_spin_unlock(&rq->lock); + } + } + + return idle; } + #endif #ifdef CONFIG_SMP --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -241,18 +241,6 @@ static int rt_se_boosted(struct sched_rt return p->prio != p->normal_prio; } -#ifdef CONFIG_SMP -static inline const struct cpumask *sched_rt_period_mask(void) -{ - return cpu_rq(smp_processor_id())->rd->span; -} -#else -static inline const struct cpumask *sched_rt_period_mask(void) -{ - return cpu_online_mask; -} -#endif - static inline struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) { @@ -302,11 +290,6 @@ static inline int rt_rq_throttled(struct return rt_rq->rt_throttled; } -static inline const struct cpumask *sched_rt_period_mask(void) -{ - return cpu_online_mask; -} - static inline struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) { @@ -524,7 +507,7 @@ static int do_sched_rt_period_timer(stru if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF) return 1; - span = sched_rt_period_mask(); + span = sched_bw_period_mask(); for_each_cpu(i, span) { int enqueue = 0; struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
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