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>

1 files changed, 29 insertions, 51 deletions

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index faf9a2f099ab..709deb33708a 100644
--- 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:
         /*