sched: Remove rq_iterator from move_one_task

Again, since we only iterate the fair class, remove the abstraction.

Since this is the last user of the rq_iterator, remove all that too.

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 709deb33708ac89bbda70a0a68145a6670378167..e48e459da98d5a91905419a44c9b796553c9440a 100644 (file)
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1814,54 +1814,6 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
  * Fair scheduling class load-balancing methods:
  */
 
-/*
- * Load-balancing iterator. Note: while the runqueue stays locked
- * during the whole iteration, the current task might be
- * dequeued so the iterator has to be dequeue-safe. Here we
- * achieve that by always pre-iterating before returning
- * the current task:
- */
-static struct task_struct *
-__load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next)
-{
-       struct task_struct *p = NULL;
-       struct sched_entity *se;
-
-       if (next == &cfs_rq->tasks)
-               return NULL;
-
-       se = list_entry(next, struct sched_entity, group_node);
-       p = task_of(se);
-       cfs_rq->balance_iterator = next->next;
-
-       return p;
-}
-
-static struct task_struct *load_balance_start_fair(void *arg)
-{
-       struct cfs_rq *cfs_rq = arg;
-
-       return __load_balance_iterator(cfs_rq, cfs_rq->tasks.next);
-}
-
-static struct task_struct *load_balance_next_fair(void *arg)
-{
-       struct cfs_rq *cfs_rq = arg;
-
-       return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator);
-}
-
-/*
- * runqueue iterator, to support SMP load-balancing between different
- * scheduling classes, without having to expose their internal data
- * structures to the load-balancing proper:
- */
-struct rq_iterator {
-       void *arg;
-       struct task_struct *(*start)(void *);
-       struct task_struct *(*next)(void *);
-};
-
 static unsigned long
 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
                unsigned long max_load_move, struct sched_domain *sd,
@@ -1929,42 +1881,6 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
 }
 #endif
 
-static int
-iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
-               struct sched_domain *sd, enum cpu_idle_type idle,
-               struct rq_iterator *iterator);
-
-/*
- * move_one_task tries to move exactly one task from busiest to this_rq, as
- * part of active balancing operations within "domain".
- * Returns 1 if successful and 0 otherwise.
- *
- * Called with both runqueues locked.
- */
-static int
-move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
-             struct sched_domain *sd, enum cpu_idle_type idle)
-{
-       struct cfs_rq *busy_cfs_rq;
-       struct rq_iterator cfs_rq_iterator;
-
-       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) {
-               /*
-                * pass busy_cfs_rq argument into
-                * load_balance_[start|next]_fair iterators
-                */
-               cfs_rq_iterator.arg = busy_cfs_rq;
-               if (iter_move_one_task(this_rq, this_cpu, busiest, sd, idle,
-                                      &cfs_rq_iterator))
-                   return 1;
-       }
-
-       return 0;
-}
-
 /*
  * pull_task - move a task from a remote runqueue to the local runqueue.
  * Both runqueues must be locked.
@@ -2029,6 +1945,42 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
        return 1;
 }
 
+/*
+ * move_one_task tries to move exactly one task from busiest to this_rq, as
+ * part of active balancing operations within "domain".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int
+move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+             struct sched_domain *sd, enum cpu_idle_type idle)
+{
+       struct task_struct *p, *n;
+       struct cfs_rq *cfs_rq;
+       int pinned = 0;
+
+       for_each_leaf_cfs_rq(busiest, cfs_rq) {
+               list_for_each_entry_safe(p, n, &cfs_rq->tasks, se.group_node) {
+
+                       if (!can_migrate_task(p, busiest, this_cpu,
+                                               sd, idle, &pinned))
+                               continue;
+
+                       pull_task(busiest, p, this_rq, this_cpu);
+                       /*
+                        * Right now, this is only the second place pull_task()
+                        * is called, so we can safely collect pull_task()
+                        * stats here rather than inside pull_task().
+                        */
+                       schedstat_inc(sd, lb_gained[idle]);
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
 static unsigned long
 balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
              unsigned long max_load_move, struct sched_domain *sd,
@@ -2126,32 +2078,6 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
        return total_load_moved > 0;
 }
 
-static int
-iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
-                  struct sched_domain *sd, enum cpu_idle_type idle,
-                  struct rq_iterator *iterator)
-{
-       struct task_struct *p = iterator->start(iterator->arg);
-       int pinned = 0;
-
-       while (p) {
-               if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
-                       pull_task(busiest, p, this_rq, this_cpu);
-                       /*
-                        * Right now, this is only the second place pull_task()
-                        * is called, so we can safely collect pull_task()
-                        * stats here rather than inside pull_task().
-                        */
-                       schedstat_inc(sd, lb_gained[idle]);
-
-                       return 1;
-               }
-               p = iterator->next(iterator->arg);
-       }
-
-       return 0;
-}
-
 /********** Helpers for find_busiest_group ************************/
 /*
  * sd_lb_stats - Structure to store the statistics of a sched_domain