Commit e3fca9e7 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner

sched: Replace post_schedule with a balance callback list

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: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.424032725@infradead.orgSigned-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 624bbdfa
...@@ -2277,23 +2277,35 @@ static struct rq *finish_task_switch(struct task_struct *prev) ...@@ -2277,23 +2277,35 @@ static struct rq *finish_task_switch(struct task_struct *prev)
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
/* rq->lock is NOT held, but preemption is disabled */ /* 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) { struct callback_head *head, *next;
void (*func)(struct rq *rq);
unsigned long flags; unsigned long flags;
raw_spin_lock_irqsave(&rq->lock, flags); raw_spin_lock_irqsave(&rq->lock, flags);
if (rq->curr->sched_class->post_schedule) head = rq->balance_callback;
rq->curr->sched_class->post_schedule(rq); rq->balance_callback = NULL;
raw_spin_unlock_irqrestore(&rq->lock, flags); 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 #else
static inline void post_schedule(struct rq *rq) static inline void balance_callback(struct rq *rq)
{ {
} }
...@@ -2311,7 +2323,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev) ...@@ -2311,7 +2323,7 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
/* finish_task_switch() drops rq->lock and enables preemtion */ /* finish_task_switch() drops rq->lock and enables preemtion */
preempt_disable(); preempt_disable();
rq = finish_task_switch(prev); rq = finish_task_switch(prev);
post_schedule(rq); balance_callback(rq);
preempt_enable(); preempt_enable();
if (current->set_child_tid) if (current->set_child_tid)
...@@ -2823,7 +2835,7 @@ static void __sched __schedule(void) ...@@ -2823,7 +2835,7 @@ static void __sched __schedule(void)
} else } else
raw_spin_unlock_irq(&rq->lock); raw_spin_unlock_irq(&rq->lock);
post_schedule(rq); balance_callback(rq);
} }
static inline void sched_submit_work(struct task_struct *tsk) static inline void sched_submit_work(struct task_struct *tsk)
...@@ -7219,7 +7231,7 @@ void __init sched_init(void) ...@@ -7219,7 +7231,7 @@ void __init sched_init(void)
rq->sd = NULL; rq->sd = NULL;
rq->rd = NULL; rq->rd = NULL;
rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE; rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
rq->post_schedule = 0; rq->balance_callback = NULL;
rq->active_balance = 0; rq->active_balance = 0;
rq->next_balance = jiffies; rq->next_balance = jiffies;
rq->push_cpu = 0; rq->push_cpu = 0;
......
...@@ -213,9 +213,16 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev) ...@@ -213,9 +213,16 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
return dl_task(prev); return dl_task(prev);
} }
static inline void set_post_schedule(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)
{ {
rq->post_schedule = has_pushable_dl_tasks(rq); if (!has_pushable_dl_tasks(rq))
return;
queue_balance_callback(rq, &per_cpu(dl_balance_head, rq->cpu), push_dl_tasks);
} }
static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq); static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
...@@ -296,7 +303,7 @@ static inline int pull_dl_task(struct rq *rq) ...@@ -296,7 +303,7 @@ static inline int pull_dl_task(struct rq *rq)
return 0; return 0;
} }
static inline void set_post_schedule(struct rq *rq) static inline void queue_push_tasks(struct rq *rq)
{ {
} }
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */
...@@ -1126,7 +1133,7 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev) ...@@ -1126,7 +1133,7 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev)
if (hrtick_enabled(rq)) if (hrtick_enabled(rq))
start_hrtick_dl(rq, p); start_hrtick_dl(rq, p);
set_post_schedule(rq); queue_push_tasks(rq);
return p; return p;
} }
...@@ -1544,11 +1551,6 @@ static int pull_dl_task(struct rq *this_rq) ...@@ -1544,11 +1551,6 @@ static int pull_dl_task(struct rq *this_rq)
return ret; return ret;
} }
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 * 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. * anytime soon on its runqueue, we try pushing it away now.
...@@ -1784,7 +1786,6 @@ const struct sched_class dl_sched_class = { ...@@ -1784,7 +1786,6 @@ const struct sched_class dl_sched_class = {
.set_cpus_allowed = set_cpus_allowed_dl, .set_cpus_allowed = set_cpus_allowed_dl,
.rq_online = rq_online_dl, .rq_online = rq_online_dl,
.rq_offline = rq_offline_dl, .rq_offline = rq_offline_dl,
.post_schedule = post_schedule_dl,
.task_woken = task_woken_dl, .task_woken = task_woken_dl,
#endif #endif
......
...@@ -354,13 +354,16 @@ static inline int has_pushable_tasks(struct rq *rq) ...@@ -354,13 +354,16 @@ static inline int has_pushable_tasks(struct rq *rq)
return !plist_head_empty(&rq->rt.pushable_tasks); return !plist_head_empty(&rq->rt.pushable_tasks);
} }
static inline void set_post_schedule(struct rq *rq) 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))
* We detect this state here so that we can avoid taking the RQ return;
* lock again later if there is no need to push
*/ queue_balance_callback(rq, &per_cpu(rt_balance_head, rq->cpu), push_rt_tasks);
rq->post_schedule = has_pushable_tasks(rq);
} }
static void enqueue_pushable_task(struct rq *rq, struct task_struct *p) static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
...@@ -417,7 +420,7 @@ static inline int pull_rt_task(struct rq *this_rq) ...@@ -417,7 +420,7 @@ static inline int pull_rt_task(struct rq *this_rq)
return 0; return 0;
} }
static inline void set_post_schedule(struct rq *rq) static inline void queue_push_tasks(struct rq *rq)
{ {
} }
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */
...@@ -1497,7 +1500,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev) ...@@ -1497,7 +1500,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev)
/* The running task is never eligible for pushing */ /* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p); dequeue_pushable_task(rq, p);
set_post_schedule(rq); queue_push_tasks(rq);
return p; return p;
} }
...@@ -2042,11 +2045,6 @@ static int pull_rt_task(struct rq *this_rq) ...@@ -2042,11 +2045,6 @@ static int pull_rt_task(struct rq *this_rq)
return ret; return ret;
} }
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 * If we are not running and we are not going to reschedule soon, we should
* try to push tasks away now * try to push tasks away now
...@@ -2318,7 +2316,6 @@ const struct sched_class rt_sched_class = { ...@@ -2318,7 +2316,6 @@ const struct sched_class rt_sched_class = {
.set_cpus_allowed = set_cpus_allowed_rt, .set_cpus_allowed = set_cpus_allowed_rt,
.rq_online = rq_online_rt, .rq_online = rq_online_rt,
.rq_offline = rq_offline_rt, .rq_offline = rq_offline_rt,
.post_schedule = post_schedule_rt,
.task_woken = task_woken_rt, .task_woken = task_woken_rt,
.switched_from = switched_from_rt, .switched_from = switched_from_rt,
#endif #endif
......
...@@ -624,9 +624,10 @@ struct rq { ...@@ -624,9 +624,10 @@ struct rq {
unsigned long cpu_capacity; unsigned long cpu_capacity;
unsigned long cpu_capacity_orig; unsigned long cpu_capacity_orig;
struct callback_head *balance_callback;
unsigned char idle_balance; unsigned char idle_balance;
/* For active balancing */ /* For active balancing */
int post_schedule;
int active_balance; int active_balance;
int push_cpu; int push_cpu;
struct cpu_stop_work active_balance_work; struct cpu_stop_work active_balance_work;
...@@ -767,6 +768,21 @@ extern int migrate_swap(struct task_struct *, struct task_struct *); ...@@ -767,6 +768,21 @@ extern int migrate_swap(struct task_struct *, struct task_struct *);
#ifdef CONFIG_SMP #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;
}
extern void sched_ttwu_pending(void); extern void sched_ttwu_pending(void);
#define rcu_dereference_check_sched_domain(p) \ #define rcu_dereference_check_sched_domain(p) \
...@@ -1192,7 +1208,6 @@ struct sched_class { ...@@ -1192,7 +1208,6 @@ struct sched_class {
int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags); int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
void (*migrate_task_rq)(struct task_struct *p, int next_cpu); void (*migrate_task_rq)(struct task_struct *p, int next_cpu);
void (*post_schedule) (struct rq *this_rq);
void (*task_waking) (struct task_struct *task); void (*task_waking) (struct task_struct *task);
void (*task_woken) (struct rq *this_rq, struct task_struct *task); void (*task_woken) (struct rq *this_rq, struct task_struct *task);
......
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