rw_semaphore: remove up/down_read_non_owner
[linux-2.6.git] / kernel / sched_fair.c
index 054cebb..433491c 100644 (file)
@@ -1076,8 +1076,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
        se->on_rq = 0;
        update_cfs_load(cfs_rq, 0);
        account_entity_dequeue(cfs_rq, se);
-       update_min_vruntime(cfs_rq);
-       update_cfs_shares(cfs_rq);
 
        /*
         * Normalize the entity after updating the min_vruntime because the
@@ -1086,6 +1084,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
         */
        if (!(flags & DEQUEUE_SLEEP))
                se->vruntime -= cfs_rq->min_vruntime;
+
+       update_min_vruntime(cfs_rq);
+       update_cfs_shares(cfs_rq);
 }
 
 /*
@@ -1344,6 +1345,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
        hrtick_update(rq);
 }
 
+static void set_next_buddy(struct sched_entity *se);
+
 /*
  * The dequeue_task method is called before nr_running is
  * decreased. We remove the task from the rbtree and
@@ -1353,14 +1356,22 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 {
        struct cfs_rq *cfs_rq;
        struct sched_entity *se = &p->se;
+       int task_sleep = flags & DEQUEUE_SLEEP;
 
        for_each_sched_entity(se) {
                cfs_rq = cfs_rq_of(se);
                dequeue_entity(cfs_rq, se, flags);
 
                /* Don't dequeue parent if it has other entities besides us */
-               if (cfs_rq->load.weight)
+               if (cfs_rq->load.weight) {
+                       /*
+                        * Bias pick_next to pick a task from this cfs_rq, as
+                        * p is sleeping when it is within its sched_slice.
+                        */
+                       if (task_sleep && parent_entity(se))
+                               set_next_buddy(parent_entity(se));
                        break;
+               }
                flags |= DEQUEUE_SLEEP;
        }
 
@@ -1574,7 +1585,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p,
                }
 
                /* Adjust by relative CPU power of the group */
-               avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
+               avg_load = (avg_load * SCHED_POWER_SCALE) / group->cpu_power;
 
                if (local_group) {
                        this_load = avg_load;
@@ -1639,6 +1650,7 @@ static int select_idle_sibling(struct task_struct *p, int target)
        /*
         * Otherwise, iterate the domains and find an elegible idle cpu.
         */
+       rcu_read_lock();
        for_each_domain(target, sd) {
                if (!(sd->flags & SD_SHARE_PKG_RESOURCES))
                        break;
@@ -1658,6 +1670,7 @@ static int select_idle_sibling(struct task_struct *p, int target)
                    cpumask_test_cpu(prev_cpu, sched_domain_span(sd)))
                        break;
        }
+       rcu_read_unlock();
 
        return target;
 }
@@ -1690,6 +1703,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
                new_cpu = prev_cpu;
        }
 
+       rcu_read_lock();
        for_each_domain(cpu, tmp) {
                if (!(tmp->flags & SD_LOAD_BALANCE))
                        continue;
@@ -1709,7 +1723,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
                                nr_running += cpu_rq(i)->cfs.nr_running;
                        }
 
-                       capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);
+                       capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
 
                        if (tmp->flags & SD_POWERSAVINGS_BALANCE)
                                nr_running /= 2;
@@ -1740,9 +1754,10 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
 
        if (affine_sd) {
                if (cpu == prev_cpu || wake_affine(affine_sd, p, sync))
-                       return select_idle_sibling(p, cpu);
-               else
-                       return select_idle_sibling(p, prev_cpu);
+                       prev_cpu = cpu;
+
+               new_cpu = select_idle_sibling(p, prev_cpu);
+               goto unlock;
        }
 
        while (sd) {
@@ -1783,6 +1798,8 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
                }
                /* while loop will break here if sd == NULL */
        }
+unlock:
+       rcu_read_unlock();
 
        return new_cpu;
 }
@@ -1840,26 +1857,26 @@ wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
 
 static void set_last_buddy(struct sched_entity *se)
 {
-       if (likely(task_of(se)->policy != SCHED_IDLE)) {
-               for_each_sched_entity(se)
-                       cfs_rq_of(se)->last = se;
-       }
+       if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+               return;
+
+       for_each_sched_entity(se)
+               cfs_rq_of(se)->last = se;
 }
 
 static void set_next_buddy(struct sched_entity *se)
 {
-       if (likely(task_of(se)->policy != SCHED_IDLE)) {
-               for_each_sched_entity(se)
-                       cfs_rq_of(se)->next = se;
-       }
+       if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE))
+               return;
+
+       for_each_sched_entity(se)
+               cfs_rq_of(se)->next = se;
 }
 
 static void set_skip_buddy(struct sched_entity *se)
 {
-       if (likely(task_of(se)->policy != SCHED_IDLE)) {
-               for_each_sched_entity(se)
-                       cfs_rq_of(se)->skip = se;
-       }
+       for_each_sched_entity(se)
+               cfs_rq_of(se)->skip = se;
 }
 
 /*
@@ -1871,12 +1888,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
        struct sched_entity *se = &curr->se, *pse = &p->se;
        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
        int scale = cfs_rq->nr_running >= sched_nr_latency;
+       int next_buddy_marked = 0;
 
        if (unlikely(se == pse))
                return;
 
-       if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK))
+       if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) {
                set_next_buddy(pse);
+               next_buddy_marked = 1;
+       }
 
        /*
         * We can come here with TIF_NEED_RESCHED already set from new task
@@ -1904,8 +1924,15 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
        update_curr(cfs_rq);
        find_matching_se(&se, &pse);
        BUG_ON(!pse);
-       if (wakeup_preempt_entity(se, pse) == 1)
+       if (wakeup_preempt_entity(se, pse) == 1) {
+               /*
+                * Bias pick_next to pick the sched entity that is
+                * triggering this preemption.
+                */
+               if (!next_buddy_marked)
+                       set_next_buddy(pse);
                goto preempt;
+       }
 
        return;
 
@@ -2116,7 +2143,7 @@ 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 cfs_rq *busiest_cfs_rq)
+             struct cfs_rq *busiest_cfs_rq)
 {
        int loops = 0, pulled = 0;
        long rem_load_move = max_load_move;
@@ -2154,9 +2181,6 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
                 */
                if (rem_load_move <= 0)
                        break;
-
-               if (p->prio < *this_best_prio)
-                       *this_best_prio = p->prio;
        }
 out:
        /*
@@ -2216,7 +2240,7 @@ 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)
+                 int *all_pinned)
 {
        long rem_load_move = max_load_move;
        int busiest_cpu = cpu_of(busiest);
@@ -2241,7 +2265,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest,
                rem_load = div_u64(rem_load, busiest_h_load + 1);
 
                moved_load = balance_tasks(this_rq, this_cpu, busiest,
-                               rem_load, sd, idle, all_pinned, this_best_prio,
+                               rem_load, sd, idle, all_pinned,
                                busiest_cfs_rq);
 
                if (!moved_load)
@@ -2267,11 +2291,11 @@ 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)
+                 int *all_pinned)
 {
        return balance_tasks(this_rq, this_cpu, busiest,
                        max_load_move, sd, idle, all_pinned,
-                       this_best_prio, &busiest->cfs);
+                       &busiest->cfs);
 }
 #endif
 
@@ -2288,12 +2312,11 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
                      int *all_pinned)
 {
        unsigned long total_load_moved = 0, load_moved;
-       int this_best_prio = this_rq->curr->prio;
 
        do {
                load_moved = load_balance_fair(this_rq, this_cpu, busiest,
                                max_load_move - total_load_moved,
-                               sd, idle, all_pinned, &this_best_prio);
+                               sd, idle, all_pinned);
 
                total_load_moved += load_moved;
 
@@ -2548,7 +2571,7 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
 
 unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
 {
-       return SCHED_LOAD_SCALE;
+       return SCHED_POWER_SCALE;
 }
 
 unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
@@ -2585,10 +2608,10 @@ unsigned long scale_rt_power(int cpu)
                available = total - rq->rt_avg;
        }
 
-       if (unlikely((s64)total < SCHED_LOAD_SCALE))
-               total = SCHED_LOAD_SCALE;
+       if (unlikely((s64)total < SCHED_POWER_SCALE))
+               total = SCHED_POWER_SCALE;
 
-       total >>= SCHED_LOAD_SHIFT;
+       total >>= SCHED_POWER_SHIFT;
 
        return div_u64(available, total);
 }
@@ -2596,7 +2619,7 @@ unsigned long scale_rt_power(int cpu)
 static void update_cpu_power(struct sched_domain *sd, int cpu)
 {
        unsigned long weight = sd->span_weight;
-       unsigned long power = SCHED_LOAD_SCALE;
+       unsigned long power = SCHED_POWER_SCALE;
        struct sched_group *sdg = sd->groups;
 
        if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
@@ -2605,7 +2628,7 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
                else
                        power *= default_scale_smt_power(sd, cpu);
 
-               power >>= SCHED_LOAD_SHIFT;
+               power >>= SCHED_POWER_SHIFT;
        }
 
        sdg->cpu_power_orig = power;
@@ -2615,10 +2638,10 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
        else
                power *= default_scale_freq_power(sd, cpu);
 
-       power >>= SCHED_LOAD_SHIFT;
+       power >>= SCHED_POWER_SHIFT;
 
        power *= scale_rt_power(cpu);
-       power >>= SCHED_LOAD_SHIFT;
+       power >>= SCHED_POWER_SHIFT;
 
        if (!power)
                power = 1;
@@ -2660,9 +2683,9 @@ static inline int
 fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
 {
        /*
-        * Only siblings can have significantly less than SCHED_LOAD_SCALE
+        * Only siblings can have significantly less than SCHED_POWER_SCALE
         */
-       if (sd->level != SD_LV_SIBLING)
+       if (!(sd->flags & SD_SHARE_CPUPOWER))
                return 0;
 
        /*
@@ -2748,7 +2771,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
        }
 
        /* Adjust by relative CPU power of the group */
-       sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;
+       sgs->avg_load = (sgs->group_load*SCHED_POWER_SCALE) / group->cpu_power;
 
        /*
         * Consider the group unbalanced when the imbalance is larger
@@ -2765,7 +2788,8 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
        if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
                sgs->group_imb = 1;
 
-       sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE);
+       sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power,
+                                               SCHED_POWER_SCALE);
        if (!sgs->group_capacity)
                sgs->group_capacity = fix_small_capacity(sd, group);
        sgs->group_weight = group->group_weight;
@@ -2939,7 +2963,7 @@ static int check_asym_packing(struct sched_domain *sd,
                return 0;
 
        *imbalance = DIV_ROUND_CLOSEST(sds->max_load * sds->busiest->cpu_power,
-                                      SCHED_LOAD_SCALE);
+                                      SCHED_POWER_SCALE);
        return 1;
 }
 
@@ -2968,7 +2992,7 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds,
                        cpu_avg_load_per_task(this_cpu);
 
        scaled_busy_load_per_task = sds->busiest_load_per_task
-                                                * SCHED_LOAD_SCALE;
+                                        * SCHED_POWER_SCALE;
        scaled_busy_load_per_task /= sds->busiest->cpu_power;
 
        if (sds->max_load - sds->this_load + scaled_busy_load_per_task >=
@@ -2987,10 +3011,10 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds,
                        min(sds->busiest_load_per_task, sds->max_load);
        pwr_now += sds->this->cpu_power *
                        min(sds->this_load_per_task, sds->this_load);
-       pwr_now /= SCHED_LOAD_SCALE;
+       pwr_now /= SCHED_POWER_SCALE;
 
        /* Amount of load we'd subtract */
-       tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) /
+       tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
                sds->busiest->cpu_power;
        if (sds->max_load > tmp)
                pwr_move += sds->busiest->cpu_power *
@@ -2998,15 +3022,15 @@ static inline void fix_small_imbalance(struct sd_lb_stats *sds,
 
        /* Amount of load we'd add */
        if (sds->max_load * sds->busiest->cpu_power <
-               sds->busiest_load_per_task * SCHED_LOAD_SCALE)
+               sds->busiest_load_per_task * SCHED_POWER_SCALE)
                tmp = (sds->max_load * sds->busiest->cpu_power) /
                        sds->this->cpu_power;
        else
-               tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) /
+               tmp = (sds->busiest_load_per_task * SCHED_POWER_SCALE) /
                        sds->this->cpu_power;
        pwr_move += sds->this->cpu_power *
                        min(sds->this_load_per_task, sds->this_load + tmp);
-       pwr_move /= SCHED_LOAD_SCALE;
+       pwr_move /= SCHED_POWER_SCALE;
 
        /* Move if we gain throughput */
        if (pwr_move > pwr_now)
@@ -3048,7 +3072,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
                load_above_capacity = (sds->busiest_nr_running -
                                                sds->busiest_group_capacity);
 
-               load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_LOAD_SCALE);
+               load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);
 
                load_above_capacity /= sds->busiest->cpu_power;
        }
@@ -3068,7 +3092,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
        /* How much load to actually move to equalise the imbalance */
        *imbalance = min(max_pull * sds->busiest->cpu_power,
                (sds->avg_load - sds->this_load) * sds->this->cpu_power)
-                       / SCHED_LOAD_SCALE;
+                       / SCHED_POWER_SCALE;
 
        /*
         * if *imbalance is less than the average load per runnable task
@@ -3137,7 +3161,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
        if (!sds.busiest || sds.busiest_nr_running == 0)
                goto out_balanced;
 
-       sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
+       sds.avg_load = (SCHED_POWER_SCALE * sds.total_load) / sds.total_pwr;
 
        /*
         * If the busiest group is imbalanced the below checks don't
@@ -3216,7 +3240,8 @@ find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
 
        for_each_cpu(i, sched_group_cpus(group)) {
                unsigned long power = power_of(i);
-               unsigned long capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);
+               unsigned long capacity = DIV_ROUND_CLOSEST(power,
+                                                          SCHED_POWER_SCALE);
                unsigned long wl;
 
                if (!capacity)
@@ -3241,7 +3266,7 @@ find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
                 * the load can be moved away from the cpu that is potentially
                 * running at a lower capacity.
                 */
-               wl = (wl * SCHED_LOAD_SCALE) / power;
+               wl = (wl * SCHED_POWER_SCALE) / power;
 
                if (wl > max_load) {
                        max_load = wl;
@@ -3479,6 +3504,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
        raw_spin_unlock(&this_rq->lock);
 
        update_shares(this_cpu);
+       rcu_read_lock();
        for_each_domain(this_cpu, sd) {
                unsigned long interval;
                int balance = 1;
@@ -3500,6 +3526,7 @@ static void idle_balance(int this_cpu, struct rq *this_rq)
                        break;
                }
        }
+       rcu_read_unlock();
 
        raw_spin_lock(&this_rq->lock);
 
@@ -3548,6 +3575,7 @@ static int active_load_balance_cpu_stop(void *data)
        double_lock_balance(busiest_rq, target_rq);
 
        /* Search for an sd spanning us and the target CPU. */
+       rcu_read_lock();
        for_each_domain(target_cpu, sd) {
                if ((sd->flags & SD_LOAD_BALANCE) &&
                    cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
@@ -3563,6 +3591,7 @@ static int active_load_balance_cpu_stop(void *data)
                else
                        schedstat_inc(sd, alb_failed);
        }
+       rcu_read_unlock();
        double_unlock_balance(busiest_rq, target_rq);
 out_unlock:
        busiest_rq->active_balance = 0;
@@ -3689,6 +3718,7 @@ static int find_new_ilb(int cpu)
 {
        struct sched_domain *sd;
        struct sched_group *ilb_group;
+       int ilb = nr_cpu_ids;
 
        /*
         * Have idle load balancer selection from semi-idle packages only
@@ -3704,20 +3734,25 @@ static int find_new_ilb(int cpu)
        if (cpumask_weight(nohz.idle_cpus_mask) < 2)
                goto out_done;
 
+       rcu_read_lock();
        for_each_flag_domain(cpu, sd, SD_POWERSAVINGS_BALANCE) {
                ilb_group = sd->groups;
 
                do {
-                       if (is_semi_idle_group(ilb_group))
-                               return cpumask_first(nohz.grp_idle_mask);
+                       if (is_semi_idle_group(ilb_group)) {
+                               ilb = cpumask_first(nohz.grp_idle_mask);
+                               goto unlock;
+                       }
 
                        ilb_group = ilb_group->next;
 
                } while (ilb_group != sd->groups);
        }
+unlock:
+       rcu_read_unlock();
 
 out_done:
-       return nr_cpu_ids;
+       return ilb;
 }
 #else /*  (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */
 static inline int find_new_ilb(int call_cpu)
@@ -3862,6 +3897,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
 
        update_shares(cpu);
 
+       rcu_read_lock();
        for_each_domain(cpu, sd) {
                if (!(sd->flags & SD_LOAD_BALANCE))
                        continue;
@@ -3907,6 +3943,7 @@ out:
                if (!balance)
                        break;
        }
+       rcu_read_unlock();
 
        /*
         * next_balance will be updated only when there is a need.