1 files changed, 31 insertions, 121 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index bc38804e40dd..12d291bf3379 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -215,7 +215,6 @@ struct runqueue {
          */
         unsigned long nr_running;
 #ifdef CONFIG_SMP
-        unsigned long prio_bias;
         unsigned long cpu_load[3];
 #endif
         unsigned long long nr_switches;
@@ -669,68 +668,13 @@ static int effective_prio(task_t *p)
         return prio;
 }
 
-#ifdef CONFIG_SMP
-static inline void inc_prio_bias(runqueue_t *rq, int prio)
-{
-        rq->prio_bias += MAX_PRIO - prio;
-}
-
-static inline void dec_prio_bias(runqueue_t *rq, int prio)
-{
-        rq->prio_bias -= MAX_PRIO - prio;
-}
-
-static inline void inc_nr_running(task_t *p, runqueue_t *rq)
-{
-        rq->nr_running++;
-        if (rt_task(p)) {
-                if (p != rq->migration_thread)
-                        /*
-                         * The migration thread does the actual balancing. Do
-                         * not bias by its priority as the ultra high priority
-                         * will skew balancing adversely.
-                         */
-                        inc_prio_bias(rq, p->prio);
-        } else
-                inc_prio_bias(rq, p->static_prio);
-}
-
-static inline void dec_nr_running(task_t *p, runqueue_t *rq)
-{
-        rq->nr_running--;
-        if (rt_task(p)) {
-                if (p != rq->migration_thread)
-                        dec_prio_bias(rq, p->prio);
-        } else
-                dec_prio_bias(rq, p->static_prio);
-}
-#else
-static inline void inc_prio_bias(runqueue_t *rq, int prio)
-{
-}
-
-static inline void dec_prio_bias(runqueue_t *rq, int prio)
-{
-}
-
-static inline void inc_nr_running(task_t *p, runqueue_t *rq)
-{
-        rq->nr_running++;
-}
-
-static inline void dec_nr_running(task_t *p, runqueue_t *rq)
-{
-        rq->nr_running--;
-}
-#endif
-
 /*
  * __activate_task - move a task to the runqueue.
  */
 static inline void __activate_task(task_t *p, runqueue_t *rq)
 {
         enqueue_task(p, rq->active);
-        inc_nr_running(p, rq);
+        rq->nr_running++;
 }
 
 /*
@@ -739,7 +683,7 @@ static inline void __activate_task(task_t *p, runqueue_t *rq)
 static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
 {
         enqueue_task_head(p, rq->active);
-        inc_nr_running(p, rq);
+        rq->nr_running++;
 }
 
 static int recalc_task_prio(task_t *p, unsigned long long now)
@@ -863,7 +807,7 @@ static void activate_task(task_t *p, runqueue_t *rq, int local)
  */
 static void deactivate_task(struct task_struct *p, runqueue_t *rq)
 {
-        dec_nr_running(p, rq);
+        rq->nr_running--;
         dequeue_task(p, p->array);
         p->array = NULL;
 }
@@ -1007,61 +951,27 @@ void kick_process(task_t *p)
  * We want to under-estimate the load of migration sources, to
  * balance conservatively.
  */
-static unsigned long __source_load(int cpu, int type, enum idle_type idle)
+static inline unsigned long source_load(int cpu, int type)
 {
         runqueue_t *rq = cpu_rq(cpu);
-        unsigned long running = rq->nr_running;
-        unsigned long source_load, cpu_load = rq->cpu_load[type-1],
-                load_now = running * SCHED_LOAD_SCALE;
-
+        unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
         if (type == 0)
-                source_load = load_now;
-        else
-                source_load = min(cpu_load, load_now);
-
-        if (running > 1 || (idle == NOT_IDLE && running))
-                /*
-                 * If we are busy rebalancing the load is biased by
-                 * priority to create 'nice' support across cpus. When
-                 * idle rebalancing we should only bias the source_load if
-                 * there is more than one task running on that queue to
-                 * prevent idle rebalance from trying to pull tasks from a
-                 * queue with only one running task.
-                 */
-                source_load = source_load * rq->prio_bias / running;
-
-        return source_load;
-}
+                return load_now;
 
-static inline unsigned long source_load(int cpu, int type)
-{
-        return __source_load(cpu, type, NOT_IDLE);
+        return min(rq->cpu_load[type-1], load_now);
 }
 
 /*
  * Return a high guess at the load of a migration-target cpu
  */
-static inline unsigned long __target_load(int cpu, int type, enum idle_type idle)
+static inline unsigned long target_load(int cpu, int type)
 {
         runqueue_t *rq = cpu_rq(cpu);
-        unsigned long running = rq->nr_running;
-        unsigned long target_load, cpu_load = rq->cpu_load[type-1],
-                load_now = running * SCHED_LOAD_SCALE;
-
+        unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
         if (type == 0)
-                target_load = load_now;
-        else
-                target_load = max(cpu_load, load_now);
-
-        if (running > 1 || (idle == NOT_IDLE && running))
-                target_load = target_load * rq->prio_bias / running;
-
-        return target_load;
-}
+                return load_now;
 
-static inline unsigned long target_load(int cpu, int type)
-{
-        return __target_load(cpu, type, NOT_IDLE);
+        return max(rq->cpu_load[type-1], load_now);
 }
 
 /*
@@ -1294,9 +1204,6 @@ static int try_to_wake_up(task_t *p, unsigned int state, int sync)
                 }
         }
 
-        if (p->last_waker_cpu != this_cpu)
-                goto out_set_cpu;
-
         if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
                 goto out_set_cpu;
 
@@ -1367,8 +1274,6 @@ out_set_cpu:
                 cpu = task_cpu(p);
         }
 
-        p->last_waker_cpu = this_cpu;
-
 out_activate:
 #endif /* CONFIG_SMP */
         if (old_state == TASK_UNINTERRUPTIBLE) {
@@ -1450,12 +1355,9 @@ void fastcall sched_fork(task_t *p, int clone_flags)
 #ifdef CONFIG_SCHEDSTATS
         memset(&p->sched_info, 0, sizeof(p->sched_info));
 #endif
-#if defined(CONFIG_SMP)
-        p->last_waker_cpu = cpu;
-#if defined(__ARCH_WANT_UNLOCKED_CTXSW)
+#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
         p->oncpu = 0;
 #endif
-#endif
 #ifdef CONFIG_PREEMPT
         /* Want to start with kernel preemption disabled. */
         task_thread_info(p)->preempt_count = 1;
@@ -1530,7 +1432,7 @@ void fastcall wake_up_new_task(task_t *p, unsigned long clone_flags)
                                 list_add_tail(&p->run_list, &current->run_list);
                                 p->array = current->array;
                                 p->array->nr_active++;
-                                inc_nr_running(p, rq);
+                                rq->nr_running++;
                         }
                         set_need_resched();
                 } else
@@ -1875,9 +1777,9 @@ void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p,
                runqueue_t *this_rq, prio_array_t *this_array, int this_cpu)
 {
         dequeue_task(p, src_array);
-        dec_nr_running(p, src_rq);
+        src_rq->nr_running--;
         set_task_cpu(p, this_cpu);
-        inc_nr_running(p, this_rq);
+        this_rq->nr_running++;
         enqueue_task(p, this_array);
         p->timestamp = (p->timestamp - src_rq->timestamp_last_tick)
                                 + this_rq->timestamp_last_tick;
@@ -2056,9 +1958,9 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
 
                         /* Bias balancing toward cpus of our domain */
                         if (local_group)
-                                load = __target_load(i, load_idx, idle);
+                                load = target_load(i, load_idx);
                         else
-                                load = __source_load(i, load_idx, idle);
+                                load = source_load(i, load_idx);
 
                         avg_load += load;
                 }
@@ -2171,7 +2073,7 @@ static runqueue_t *find_busiest_queue(struct sched_group *group,
         int i;
 
         for_each_cpu_mask(i, group->cpumask) {
-                load = __source_load(i, 0, idle);
+                load = source_load(i, 0);
 
                 if (load > max_load) {
                         max_load = load;
@@ -3571,10 +3473,8 @@ void set_user_nice(task_t *p, long nice)
                 goto out_unlock;
         }
         array = p->array;
-        if (array) {
+        if (array)
                 dequeue_task(p, array);
-                dec_prio_bias(rq, p->static_prio);
-        }
 
         old_prio = p->prio;
         new_prio = NICE_TO_PRIO(nice);
@@ -3584,7 +3484,6 @@ void set_user_nice(task_t *p, long nice)
 
         if (array) {
                 enqueue_task(p, array);
-                inc_prio_bias(rq, p->static_prio);
                 /*
                  * If the task increased its priority or is running and
                  * lowered its priority, then reschedule its CPU:
@@ -5159,7 +5058,18 @@ static void init_sched_build_groups(struct sched_group groups[], cpumask_t span,
 #define MAX_DOMAIN_DISTANCE 32
 
 static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] =
-                { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = -1LL };
+                { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] =
+/*
+ * Architectures may override the migration cost and thus avoid
+ * boot-time calibration. Unit is nanoseconds. Mostly useful for
+ * virtualized hardware:
+ */
+#ifdef CONFIG_DEFAULT_MIGRATION_COST
+                        CONFIG_DEFAULT_MIGRATION_COST
+#else
+                        -1LL
+#endif
+};
 
 /*
  * Allow override of migration cost - in units of microseconds.