sched: Remove rq_iterator usage from load_balance_fair

Since we only ever iterate the fair class, do away with this abstraction.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index faf9a2f..709deb3 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1866,26 +1866,9 @@ static unsigned long
 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
                unsigned long max_load_move, struct sched_domain *sd,
                enum cpu_idle_type idle, int *all_pinned,
-               int *this_best_prio, struct rq_iterator *iterator);
+               int *this_best_prio, struct cfs_rq *busiest_cfs_rq);
 
 
-static unsigned long
-__load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
-               unsigned long max_load_move, struct sched_domain *sd,
-               enum cpu_idle_type idle, int *all_pinned, int *this_best_prio,
-               struct cfs_rq *cfs_rq)
-{
-       struct rq_iterator cfs_rq_iterator;
-
-       cfs_rq_iterator.start = load_balance_start_fair;
-       cfs_rq_iterator.next = load_balance_next_fair;
-       cfs_rq_iterator.arg = cfs_rq;
-
-       return balance_tasks(this_rq, this_cpu, busiest,
-                       max_load_move, sd, idle, all_pinned,
-                       this_best_prio, &cfs_rq_iterator);
-}
-
 #ifdef CONFIG_FAIR_GROUP_SCHED
 static unsigned long
 load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
@@ -1915,9 +1898,9 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
                rem_load = (u64)rem_load_move * busiest_weight;
                rem_load = div_u64(rem_load, busiest_h_load + 1);
 
-               moved_load = __load_balance_fair(this_rq, this_cpu, busiest,
+               moved_load = balance_tasks(this_rq, this_cpu, busiest,
                                rem_load, sd, idle, all_pinned, this_best_prio,
-                               tg->cfs_rq[busiest_cpu]);
+                               busiest_cfs_rq);
 
                if (!moved_load)
                        continue;
@@ -1940,7 +1923,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
                  struct sched_domain *sd, enum cpu_idle_type idle,
                  int *all_pinned, int *this_best_prio)
 {
-       return __load_balance_fair(this_rq, this_cpu, busiest,
+       return balance_tasks(this_rq, this_cpu, busiest,
                        max_load_move, sd, idle, all_pinned,
                        this_best_prio, &busiest->cfs);
 }
@@ -2050,53 +2033,48 @@ static unsigned long
 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
              unsigned long max_load_move, struct sched_domain *sd,
              enum cpu_idle_type idle, int *all_pinned,
-             int *this_best_prio, struct rq_iterator *iterator)
+             int *this_best_prio, struct cfs_rq *busiest_cfs_rq)
 {
        int loops = 0, pulled = 0, pinned = 0;
-       struct task_struct *p;
        long rem_load_move = max_load_move;
+       struct task_struct *p, *n;
 
        if (max_load_move == 0)
                goto out;
 
        pinned = 1;
 
-       /*
-        * Start the load-balancing iterator:
-        */
-       p = iterator->start(iterator->arg);
-next:
-       if (!p || loops++ > sysctl_sched_nr_migrate)
-               goto out;
+       list_for_each_entry_safe(p, n, &busiest_cfs_rq->tasks, se.group_node) {
+               if (loops++ > sysctl_sched_nr_migrate)
+                       break;
 
-       if ((p->se.load.weight >> 1) > rem_load_move ||
-           !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
-               p = iterator->next(iterator->arg);
-               goto next;
-       }
+               if ((p->se.load.weight >> 1) > rem_load_move ||
+                   !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned))
+                       continue;
 
-       pull_task(busiest, p, this_rq, this_cpu);
-       pulled++;
-       rem_load_move -= p->se.load.weight;
+               pull_task(busiest, p, this_rq, this_cpu);
+               pulled++;
+               rem_load_move -= p->se.load.weight;
 
 #ifdef CONFIG_PREEMPT
-       /*
-        * NEWIDLE balancing is a source of latency, so preemptible kernels
-        * will stop after the first task is pulled to minimize the critical
-        * section.
-        */
-       if (idle == CPU_NEWLY_IDLE)
-               goto out;
+               /*
+                * NEWIDLE balancing is a source of latency, so preemptible
+                * kernels will stop after the first task is pulled to minimize
+                * the critical section.
+                */
+               if (idle == CPU_NEWLY_IDLE)
+                       break;
 #endif
 
-       /*
-        * We only want to steal up to the prescribed amount of weighted load.
-        */
-       if (rem_load_move > 0) {
+               /*
+                * We only want to steal up to the prescribed amount of
+                * weighted load.
+                */
+               if (rem_load_move <= 0)
+                       break;
+
                if (p->prio < *this_best_prio)
                        *this_best_prio = p->prio;
-               p = iterator->next(iterator->arg);
-               goto next;
        }
 out:
        /*