1 files changed, 67 insertions, 32 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index cc9cd5b710a6..8607795fad69 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -838,11 +838,35 @@ struct rq_iterator {
         struct task_struct *(*next)(void *);
 };
 
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-                      unsigned long max_nr_move, unsigned long max_load_move,
-                      struct sched_domain *sd, enum cpu_idle_type idle,
-                      int *all_pinned, unsigned long *load_moved,
-                      int *this_best_prio, struct rq_iterator *iterator);
+#ifdef CONFIG_SMP
+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);
+
+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);
+#else
+static inline 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)
+{
+        return 0;
+}
+
+static inline 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)
+{
+        return 0;
+}
+#endif
 
 #include "sched_stats.h"
 #include "sched_idletask.c"
@@ -2224,17 +2248,17 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
         return 1;
 }
 
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-                      unsigned long max_nr_move, unsigned long max_load_move,
-                      struct sched_domain *sd, enum cpu_idle_type idle,
-                      int *all_pinned, unsigned long *load_moved,
-                      int *this_best_prio, struct rq_iterator *iterator)
+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 pulled = 0, pinned = 0, skip_for_load;
         struct task_struct *p;
         long rem_load_move = max_load_move;
 
-        if (max_nr_move == 0 || max_load_move == 0)
+        if (max_load_move == 0)
                 goto out;
 
         pinned = 1;
@@ -2267,7 +2291,7 @@ next:
          * We only want to steal up to the prescribed number of tasks
          * and the prescribed amount of weighted load.
          */
-        if (pulled < max_nr_move && rem_load_move > 0) {
+        if (rem_load_move > 0) {
                 if (p->prio < *this_best_prio)
                         *this_best_prio = p->prio;
                 p = iterator->next(iterator->arg);
@@ -2275,7 +2299,7 @@ next:
         }
 out:
         /*
-         * Right now, this is the only place pull_task() is called,
+         * Right now, this is one of only two places pull_task() is called,
          * so we can safely collect pull_task() stats here rather than
          * inside pull_task().
          */
@@ -2283,8 +2307,8 @@ out:
 
         if (all_pinned)
                 *all_pinned = pinned;
-        *load_moved = max_load_move - rem_load_move;
-        return pulled;
+
+        return max_load_move - rem_load_move;
 }
 
 /*
@@ -2306,7 +2330,7 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
         do {
                 total_load_moved +=
                         class->load_balance(this_rq, this_cpu, busiest,
-                                ULONG_MAX, max_load_move - total_load_moved,
+                                max_load_move - total_load_moved,
                                 sd, idle, all_pinned, &this_best_prio);
                 class = class->next;
         } while (class && max_load_move > total_load_moved);
@@ -2314,6 +2338,32 @@ 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;
+}
+
 /*
  * move_one_task tries to move exactly one task from busiest to this_rq, as
  * part of active balancing operations within "domain".
@@ -2325,12 +2375,9 @@ static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
                          struct sched_domain *sd, enum cpu_idle_type idle)
 {
         const struct sched_class *class;
-        int this_best_prio = MAX_PRIO;
 
         for (class = sched_class_highest; class; class = class->next)
-                if (class->load_balance(this_rq, this_cpu, busiest,
-                                        1, ULONG_MAX, sd, idle, NULL,
-                                        &this_best_prio))
+                if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
                         return 1;
 
         return 0;
@@ -3267,18 +3314,6 @@ static inline void idle_balance(int cpu, struct rq *rq)
 {
 }
 
-/* Avoid "used but not defined" warning on UP */
-static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
-                      unsigned long max_nr_move, unsigned long max_load_move,
-                      struct sched_domain *sd, enum cpu_idle_type idle,
-                      int *all_pinned, unsigned long *load_moved,
-                      int *this_best_prio, struct rq_iterator *iterator)
-{
-        *load_moved = 0;
-
-        return 0;
-}
-
 #endif
 
 DEFINE_PER_CPU(struct kernel_stat, kstat);