static inline struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
{
- struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
- struct sched_entity *se = NULL;
- struct rb_node *parent;
+ struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
- while (*link) {
- parent = *link;
- se = rb_entry(parent, struct sched_entity, run_node);
- link = &parent->rb_right;
- }
+ if (!last)
+ return NULL;
- return se;
+ return rb_entry(last, struct sched_entity, run_node);
}
/**************************************************************
return se->parent;
}
-#define GROUP_IMBALANCE_PCT 20
-
#else /* CONFIG_FAIR_GROUP_SCHED */
#define for_each_sched_entity(se) \
static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup)
{
struct cfs_rq *cfs_rq;
- struct sched_entity *se = &p->se,
- *topse = NULL; /* Highest schedulable entity */
- int incload = 1;
+ struct sched_entity *se = &p->se;
for_each_sched_entity(se) {
- topse = se;
- if (se->on_rq) {
- incload = 0;
+ if (se->on_rq)
break;
- }
cfs_rq = cfs_rq_of(se);
enqueue_entity(cfs_rq, se, wakeup);
wakeup = 1;
}
- /* Increment cpu load if we just enqueued the first task of a group on
- * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs
- * at the highest grouping level.
- */
- if (incload)
- inc_cpu_load(rq, topse->load.weight);
hrtick_start_fair(rq, rq->curr);
}
static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
{
struct cfs_rq *cfs_rq;
- struct sched_entity *se = &p->se,
- *topse = NULL; /* Highest schedulable entity */
- int decload = 1;
+ struct sched_entity *se = &p->se;
for_each_sched_entity(se) {
- topse = se;
cfs_rq = cfs_rq_of(se);
dequeue_entity(cfs_rq, se, sleep);
/* Don't dequeue parent if it has other entities besides us */
- if (cfs_rq->load.weight) {
- if (parent_entity(se))
- decload = 0;
+ if (cfs_rq->load.weight)
break;
- }
sleep = 1;
}
- /* Decrement cpu load if we just dequeued the last task of a group on
- * 'rq->cpu'. 'topse' represents the group to which task 'p' belongs
- * at the highest grouping level.
- */
- if (decload)
- dec_cpu_load(rq, topse->load.weight);
hrtick_start_fair(rq, rq->curr);
}
}
gran = sysctl_sched_wakeup_granularity;
- if (unlikely(se->load.weight != NICE_0_LOAD))
+ /*
+ * More easily preempt - nice tasks, while not making
+ * it harder for + nice tasks.
+ */
+ if (unlikely(se->load.weight > NICE_0_LOAD))
gran = calc_delta_fair(gran, &se->load);
if (pse->vruntime + gran < se->vruntime)
return __load_balance_iterator(cfs_rq, cfs_rq->rb_load_balance_curr);
}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static int cfs_rq_best_prio(struct cfs_rq *cfs_rq)
+{
+ struct sched_entity *curr;
+ struct task_struct *p;
+
+ if (!cfs_rq->nr_running || !first_fair(cfs_rq))
+ return MAX_PRIO;
+
+ curr = cfs_rq->curr;
+ if (!curr)
+ curr = __pick_next_entity(cfs_rq);
+
+ p = task_of(curr);
+
+ return p->prio;
+}
+#endif
+
static unsigned long
load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_load_move,
struct cfs_rq *busy_cfs_rq;
long rem_load_move = max_load_move;
struct rq_iterator cfs_rq_iterator;
- unsigned long load_moved;
cfs_rq_iterator.start = load_balance_start_fair;
cfs_rq_iterator.next = load_balance_next_fair;
for_each_leaf_cfs_rq(busiest, busy_cfs_rq) {
#ifdef CONFIG_FAIR_GROUP_SCHED
- struct cfs_rq *this_cfs_rq = busy_cfs_rq->tg->cfs_rq[this_cpu];
- unsigned long maxload, task_load, group_weight;
- unsigned long thisload, per_task_load;
- struct sched_entity *se = busy_cfs_rq->tg->se[busiest->cpu];
+ struct cfs_rq *this_cfs_rq;
+ long imbalance;
+ unsigned long maxload;
- task_load = busy_cfs_rq->load.weight;
- group_weight = se->load.weight;
+ this_cfs_rq = cpu_cfs_rq(busy_cfs_rq, this_cpu);
- /*
- * 'group_weight' is contributed by tasks of total weight
- * 'task_load'. To move 'rem_load_move' worth of weight only,
- * we need to move a maximum task load of:
- *
- * maxload = (remload / group_weight) * task_load;
- */
- maxload = (rem_load_move * task_load) / group_weight;
-
- if (!maxload || !task_load)
+ imbalance = busy_cfs_rq->load.weight - this_cfs_rq->load.weight;
+ /* Don't pull if this_cfs_rq has more load than busy_cfs_rq */
+ if (imbalance <= 0)
continue;
- per_task_load = task_load / busy_cfs_rq->nr_running;
- /*
- * balance_tasks will try to forcibly move atleast one task if
- * possible (because of SCHED_LOAD_SCALE_FUZZ). Avoid that if
- * maxload is less than GROUP_IMBALANCE_FUZZ% the per_task_load.
- */
- if (100 * maxload < GROUP_IMBALANCE_PCT * per_task_load)
- continue;
+ /* Don't pull more than imbalance/2 */
+ imbalance /= 2;
+ maxload = min(rem_load_move, imbalance);
- /* Disable priority-based load balance */
- *this_best_prio = 0;
- thisload = this_cfs_rq->load.weight;
+ *this_best_prio = cfs_rq_best_prio(this_cfs_rq);
#else
# define maxload rem_load_move
#endif
* load_balance_[start|next]_fair iterators
*/
cfs_rq_iterator.arg = busy_cfs_rq;
- load_moved = balance_tasks(this_rq, this_cpu, busiest,
+ rem_load_move -= balance_tasks(this_rq, this_cpu, busiest,
maxload, sd, idle, all_pinned,
this_best_prio,
&cfs_rq_iterator);
-#ifdef CONFIG_FAIR_GROUP_SCHED
- /*
- * load_moved holds the task load that was moved. The
- * effective (group) weight moved would be:
- * load_moved_eff = load_moved/task_load * group_weight;
- */
- load_moved = (group_weight * load_moved) / task_load;
-
- /* Adjust shares on both cpus to reflect load_moved */
- group_weight -= load_moved;
- set_se_shares(se, group_weight);
-
- se = busy_cfs_rq->tg->se[this_cpu];
- if (!thisload)
- group_weight = load_moved;
- else
- group_weight = se->load.weight + load_moved;
- set_se_shares(se, group_weight);
-#endif
-
- rem_load_move -= load_moved;
-
if (rem_load_move <= 0)
break;
}
set_next_entity(cfs_rq_of(se), se);
}
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static void moved_group_fair(struct task_struct *p)
+{
+ struct cfs_rq *cfs_rq = task_cfs_rq(p);
+
+ update_curr(cfs_rq);
+ place_entity(cfs_rq, &p->se, 1);
+}
+#endif
+
/*
* All the scheduling class methods:
*/
.prio_changed = prio_changed_fair,
.switched_to = switched_to_fair,
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ .moved_group = moved_group_fair,
+#endif
};
#ifdef CONFIG_SCHED_DEBUG
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