From: Peter Zijlstra <pet...@infradead.org> Generalize the post_schedule() stuff into a balance callback list. This allows us to more easily use it outside of schedule() and cross sched_class.
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: ktk...@parallels.com Cc: rost...@goodmis.org Cc: juri.le...@gmail.com Cc: pang.xun...@linaro.org Cc: o...@redhat.com Cc: wanpeng...@linux.intel.com Cc: umgwanakikb...@gmail.com Link: http://lkml.kernel.org/r/20150611124742.424032...@infradead.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> Signed-off-by: Byungchul Park <byungchul.p...@lge.com> Conflicts: kernel/sched/core.c kernel/sched/deadline.c kernel/sched/rt.c kernel/sched/sched.h --- kernel/sched/core.c | 36 ++++++++++++++++++++++++------------ kernel/sched/deadline.c | 23 ++++++++++++++++------- kernel/sched/rt.c | 27 ++++++++++++++++----------- kernel/sched/sched.h | 19 +++++++++++++++++-- 4 files changed, 73 insertions(+), 32 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index bbe9577..cc1be56 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2179,18 +2179,30 @@ static inline void pre_schedule(struct rq *rq, struct task_struct *prev) } /* rq->lock is NOT held, but preemption is disabled */ -static inline void post_schedule(struct rq *rq) +static void __balance_callback(struct rq *rq) { - if (rq->post_schedule) { - unsigned long flags; + struct callback_head *head, *next; + void (*func)(struct rq *rq); + unsigned long flags; - raw_spin_lock_irqsave(&rq->lock, flags); - if (rq->curr->sched_class->post_schedule) - rq->curr->sched_class->post_schedule(rq); - raw_spin_unlock_irqrestore(&rq->lock, flags); + raw_spin_lock_irqsave(&rq->lock, flags); + head = rq->balance_callback; + rq->balance_callback = NULL; + while (head) { + func = (void (*)(struct rq *))head->func; + next = head->next; + head->next = NULL; + head = next; - rq->post_schedule = 0; + func(rq); } + raw_spin_unlock_irqrestore(&rq->lock, flags); +} + +static inline void balance_callback(struct rq *rq) +{ + if (unlikely(rq->balance_callback)) + __balance_callback(rq); } #else @@ -2199,7 +2211,7 @@ static inline void pre_schedule(struct rq *rq, struct task_struct *p) { } -static inline void post_schedule(struct rq *rq) +static inline void balance_callback(struct rq *rq) { } @@ -2220,7 +2232,7 @@ asmlinkage void schedule_tail(struct task_struct *prev) * FIXME: do we need to worry about rq being invalidated by the * task_switch? */ - post_schedule(rq); + balance_callback(rq); #ifdef __ARCH_WANT_UNLOCKED_CTXSW /* In this case, finish_task_switch does not reenable preemption */ @@ -2732,7 +2744,7 @@ need_resched: } else raw_spin_unlock_irq(&rq->lock); - post_schedule(rq); + balance_callback(rq); sched_preempt_enable_no_resched(); if (need_resched()) @@ -6902,7 +6914,7 @@ void __init sched_init(void) rq->sd = NULL; rq->rd = NULL; rq->cpu_power = SCHED_POWER_SCALE; - rq->post_schedule = 0; + rq->balance_callback = NULL; rq->active_balance = 0; rq->next_balance = jiffies; rq->push_cpu = 0; diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 8d3c5dd..aaefe1b 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -210,6 +210,18 @@ static inline int has_pushable_dl_tasks(struct rq *rq) static int push_dl_task(struct rq *rq); +static DEFINE_PER_CPU(struct callback_head, dl_balance_head); + +static void push_dl_tasks(struct rq *); + +static inline void queue_push_tasks(struct rq *rq) +{ + if (!has_pushable_dl_tasks(rq)) + return; + + queue_balance_callback(rq, &per_cpu(dl_balance_head, rq->cpu), push_dl_tasks); +} + #else static inline @@ -232,6 +244,9 @@ void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq) { } +static inline void queue_push_tasks(struct rq *rq) +{ +} #endif /* CONFIG_SMP */ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags); @@ -1005,7 +1020,7 @@ struct task_struct *pick_next_task_dl(struct rq *rq) #endif #ifdef CONFIG_SMP - rq->post_schedule = has_pushable_dl_tasks(rq); + queue_push_tasks(rq); #endif /* CONFIG_SMP */ return p; @@ -1422,11 +1437,6 @@ static void pre_schedule_dl(struct rq *rq, struct task_struct *prev) pull_dl_task(rq); } -static void post_schedule_dl(struct rq *rq) -{ - push_dl_tasks(rq); -} - /* * Since the task is not running and a reschedule is not going to happen * anytime soon on its runqueue, we try pushing it away now. @@ -1615,7 +1625,6 @@ const struct sched_class dl_sched_class = { .rq_online = rq_online_dl, .rq_offline = rq_offline_dl, .pre_schedule = pre_schedule_dl, - .post_schedule = post_schedule_dl, .task_woken = task_woken_dl, #endif diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 27b8e83..2b980d0 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -315,6 +315,18 @@ static inline int has_pushable_tasks(struct rq *rq) return !plist_head_empty(&rq->rt.pushable_tasks); } +static DEFINE_PER_CPU(struct callback_head, rt_balance_head); + +static void push_rt_tasks(struct rq *); + +static inline void queue_push_tasks(struct rq *rq) +{ + if (!has_pushable_tasks(rq)) + return; + + queue_balance_callback(rq, &per_cpu(rt_balance_head, rq->cpu), push_rt_tasks); +} + static void enqueue_pushable_task(struct rq *rq, struct task_struct *p) { plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks); @@ -359,6 +371,9 @@ void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { } +static inline void queue_push_tasks(struct rq *rq) +{ +} #endif /* CONFIG_SMP */ static inline int on_rt_rq(struct sched_rt_entity *rt_se) @@ -1349,11 +1364,7 @@ static struct task_struct *pick_next_task_rt(struct rq *rq) dequeue_pushable_task(rq, p); #ifdef CONFIG_SMP - /* - * We detect this state here so that we can avoid taking the RQ - * lock again later if there is no need to push - */ - rq->post_schedule = has_pushable_tasks(rq); + queue_push_tasks(rq); #endif return p; @@ -1731,11 +1742,6 @@ static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) pull_rt_task(rq); } -static void post_schedule_rt(struct rq *rq) -{ - push_rt_tasks(rq); -} - /* * If we are not running and we are not going to reschedule soon, we should * try to push tasks away now @@ -2008,7 +2014,6 @@ const struct sched_class rt_sched_class = { .rq_online = rq_online_rt, .rq_offline = rq_offline_rt, .pre_schedule = pre_schedule_rt, - .post_schedule = post_schedule_rt, .task_woken = task_woken_rt, .switched_from = switched_from_rt, #endif diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 835b6ef..675e147 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -587,9 +587,10 @@ struct rq { unsigned long cpu_power; + struct callback_head *balance_callback; + unsigned char idle_balance; /* For active balancing */ - int post_schedule; int active_balance; int push_cpu; struct cpu_stop_work active_balance_work; @@ -690,6 +691,21 @@ extern int migrate_swap(struct task_struct *, struct task_struct *); #ifdef CONFIG_SMP +static inline void +queue_balance_callback(struct rq *rq, + struct callback_head *head, + void (*func)(struct rq *rq)) +{ + lockdep_assert_held(&rq->lock); + + if (unlikely(head->next)) + return; + + head->func = (void (*)(struct callback_head *))func; + head->next = rq->balance_callback; + rq->balance_callback = head; +} + #define rcu_dereference_check_sched_domain(p) \ rcu_dereference_check((p), \ lockdep_is_held(&sched_domains_mutex)) @@ -1131,7 +1147,6 @@ struct sched_class { void (*migrate_task_rq)(struct task_struct *p, int next_cpu); void (*pre_schedule) (struct rq *this_rq, struct task_struct *task); - void (*post_schedule) (struct rq *this_rq); void (*task_waking) (struct task_struct *task); void (*task_woken) (struct rq *this_rq, struct task_struct *task); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
