sched: remove the sleep-bonus interactivity code

remove the sleep-bonus interactivity code from the core scheduler.

scheduling policy is implemented in the policy modules, and CFS does
not need such type of heuristics.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 8e44da6..f5a204b 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -894,7 +894,7 @@ static inline int __normal_prio(struct task_struct *p)
 {
        int bonus, prio;
 
-       bonus = CURRENT_BONUS(p) - MAX_BONUS / 2;
+       bonus = 0;
 
        prio = p->static_prio - bonus;
        if (prio < MAX_RT_PRIO)
@@ -970,42 +970,6 @@ static inline void __activate_idle_task(struct task_struct *p, struct rq *rq)
  */
 static int recalc_task_prio(struct task_struct *p, unsigned long long now)
 {
-       /* Caller must always ensure 'now >= p->timestamp' */
-       unsigned long sleep_time = now - p->timestamp;
-
-       if (batch_task(p))
-               sleep_time = 0;
-
-       if (likely(sleep_time > 0)) {
-               /*
-                * This ceiling is set to the lowest priority that would allow
-                * a task to be reinserted into the active array on timeslice
-                * completion.
-                */
-               unsigned long ceiling = INTERACTIVE_SLEEP(p);
-
-               if (p->mm && sleep_time > ceiling && p->sleep_avg < ceiling) {
-                       /*
-                        * Prevents user tasks from achieving best priority
-                        * with one single large enough sleep.
-                        */
-                       p->sleep_avg = ceiling;
-               } else {
-                       /*
-                        * This code gives a bonus to interactive tasks.
-                        *
-                        * The boost works by updating the 'average sleep time'
-                        * value here, based on ->timestamp. The more time a
-                        * task spends sleeping, the higher the average gets -
-                        * and the higher the priority boost gets as well.
-                        */
-                       p->sleep_avg += sleep_time;
-
-               }
-               if (p->sleep_avg > NS_MAX_SLEEP_AVG)
-                       p->sleep_avg = NS_MAX_SLEEP_AVG;
-       }
-
        return effective_prio(p);
 }
 
@@ -3560,9 +3524,6 @@ switch_tasks:
        clear_tsk_need_resched(prev);
        rcu_qsctr_inc(task_cpu(prev));
 
-       prev->sleep_avg -= run_time;
-       if ((long)prev->sleep_avg <= 0)
-               prev->sleep_avg = 0;
        prev->timestamp = prev->last_ran = now;
 
        sched_info_switch(prev, next);
@@ -4204,11 +4165,6 @@ static void __setscheduler(struct task_struct *p, int policy, int prio)
        p->normal_prio = normal_prio(p);
        /* we are holding p->pi_lock already */
        p->prio = rt_mutex_getprio(p);
-       /*
-        * SCHED_BATCH tasks are treated as perpetual CPU hogs:
-        */
-       if (policy == SCHED_BATCH)
-               p->sleep_avg = 0;
        set_load_weight(p);
 }
 
@@ -4931,7 +4887,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
        unsigned long flags;
 
        idle->timestamp = sched_clock();
-       idle->sleep_avg = 0;
        idle->array = NULL;
        idle->prio = idle->normal_prio = MAX_PRIO;
        idle->state = TASK_RUNNING;