- for_each_class(class) {
- if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
- return 1;
- }
-
- return 0;
-}
-/********** Helpers for find_busiest_group ************************/
-/*
- * sd_lb_stats - Structure to store the statistics of a sched_domain
- * during load balancing.
- */
-struct sd_lb_stats {
- struct sched_group *busiest; /* Busiest group in this sd */
- struct sched_group *this; /* Local group in this sd */
- unsigned long total_load; /* Total load of all groups in sd */
- unsigned long total_pwr; /* Total power of all groups in sd */
- unsigned long avg_load; /* Average load across all groups in sd */
-
- /** Statistics of this group */
- unsigned long this_load;
- unsigned long this_load_per_task;
- unsigned long this_nr_running;
-
- /* Statistics of the busiest group */
- unsigned long max_load;
- unsigned long busiest_load_per_task;
- unsigned long busiest_nr_running;
-
- int group_imb; /* Is there imbalance in this sd */
-#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- int power_savings_balance; /* Is powersave balance needed for this sd */
- struct sched_group *group_min; /* Least loaded group in sd */
- struct sched_group *group_leader; /* Group which relieves group_min */
- unsigned long min_load_per_task; /* load_per_task in group_min */
- unsigned long leader_nr_running; /* Nr running of group_leader */
- unsigned long min_nr_running; /* Nr running of group_min */
-#endif
-};
-
-/*
- * sg_lb_stats - stats of a sched_group required for load_balancing
- */
-struct sg_lb_stats {
- unsigned long avg_load; /*Avg load across the CPUs of the group */
- unsigned long group_load; /* Total load over the CPUs of the group */
- unsigned long sum_nr_running; /* Nr tasks running in the group */
- unsigned long sum_weighted_load; /* Weighted load of group's tasks */
- unsigned long group_capacity;
- int group_imb; /* Is there an imbalance in the group ? */
-};
-
-/**
- * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
- * @group: The group whose first cpu is to be returned.
- */
-static inline unsigned int group_first_cpu(struct sched_group *group)
-{
- return cpumask_first(sched_group_cpus(group));
-}
-
-/**
- * get_sd_load_idx - Obtain the load index for a given sched domain.
- * @sd: The sched_domain whose load_idx is to be obtained.
- * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
- */
-static inline int get_sd_load_idx(struct sched_domain *sd,
- enum cpu_idle_type idle)
-{
- int load_idx;
-
- switch (idle) {
- case CPU_NOT_IDLE:
- load_idx = sd->busy_idx;
- break;
-
- case CPU_NEWLY_IDLE:
- load_idx = sd->newidle_idx;
- break;
- default:
- load_idx = sd->idle_idx;
- break;
- }
-
- return load_idx;
-}
-
-
-#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
-/**
- * init_sd_power_savings_stats - Initialize power savings statistics for
- * the given sched_domain, during load balancing.
- *
- * @sd: Sched domain whose power-savings statistics are to be initialized.
- * @sds: Variable containing the statistics for sd.
- * @idle: Idle status of the CPU at which we're performing load-balancing.
- */
-static inline void init_sd_power_savings_stats(struct sched_domain *sd,
- struct sd_lb_stats *sds, enum cpu_idle_type idle)
-{
- /*
- * Busy processors will not participate in power savings
- * balance.
- */
- if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
- sds->power_savings_balance = 0;
- else {
- sds->power_savings_balance = 1;
- sds->min_nr_running = ULONG_MAX;
- sds->leader_nr_running = 0;
- }
-}
-
-/**
- * update_sd_power_savings_stats - Update the power saving stats for a
- * sched_domain while performing load balancing.
- *
- * @group: sched_group belonging to the sched_domain under consideration.
- * @sds: Variable containing the statistics of the sched_domain
- * @local_group: Does group contain the CPU for which we're performing
- * load balancing ?
- * @sgs: Variable containing the statistics of the group.
- */
-static inline void update_sd_power_savings_stats(struct sched_group *group,
- struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
-{
-
- if (!sds->power_savings_balance)
- return;
-
- /*
- * If the local group is idle or completely loaded
- * no need to do power savings balance at this domain
- */
- if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
- !sds->this_nr_running))
- sds->power_savings_balance = 0;
-
- /*
- * If a group is already running at full capacity or idle,
- * don't include that group in power savings calculations
- */
- if (!sds->power_savings_balance ||
- sgs->sum_nr_running >= sgs->group_capacity ||
- !sgs->sum_nr_running)
- return;
-
- /*
- * Calculate the group which has the least non-idle load.
- * This is the group from where we need to pick up the load
- * for saving power
- */
- if ((sgs->sum_nr_running < sds->min_nr_running) ||
- (sgs->sum_nr_running == sds->min_nr_running &&
- group_first_cpu(group) > group_first_cpu(sds->group_min))) {
- sds->group_min = group;
- sds->min_nr_running = sgs->sum_nr_running;
- sds->min_load_per_task = sgs->sum_weighted_load /
- sgs->sum_nr_running;
- }
-
- /*
- * Calculate the group which is almost near its
- * capacity but still has some space to pick up some load
- * from other group and save more power
- */
- if (sgs->sum_nr_running + 1 > sgs->group_capacity)
- return;
-
- if (sgs->sum_nr_running > sds->leader_nr_running ||
- (sgs->sum_nr_running == sds->leader_nr_running &&
- group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
- sds->group_leader = group;
- sds->leader_nr_running = sgs->sum_nr_running;
- }
-}
-
-/**
- * check_power_save_busiest_group - see if there is potential for some power-savings balance
- * @sds: Variable containing the statistics of the sched_domain
- * under consideration.
- * @this_cpu: Cpu at which we're currently performing load-balancing.
- * @imbalance: Variable to store the imbalance.
- *
- * Description:
- * Check if we have potential to perform some power-savings balance.
- * If yes, set the busiest group to be the least loaded group in the
- * sched_domain, so that it's CPUs can be put to idle.
- *
- * Returns 1 if there is potential to perform power-savings balance.
- * Else returns 0.
- */
-static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- if (!sds->power_savings_balance)
- return 0;
-
- if (sds->this != sds->group_leader ||
- sds->group_leader == sds->group_min)
- return 0;
-
- *imbalance = sds->min_load_per_task;
- sds->busiest = sds->group_min;
-
- return 1;
-
-}
-#else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-static inline void init_sd_power_savings_stats(struct sched_domain *sd,
- struct sd_lb_stats *sds, enum cpu_idle_type idle)
-{
- return;
-}
-
-static inline void update_sd_power_savings_stats(struct sched_group *group,
- struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
-{
- return;
-}
-
-static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- return 0;
-}
-#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
-
-
-unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
-{
- return SCHED_LOAD_SCALE;
-}
-
-unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
-{
- return default_scale_freq_power(sd, cpu);
-}
-
-unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
-{
- unsigned long weight = cpumask_weight(sched_domain_span(sd));
- unsigned long smt_gain = sd->smt_gain;
-
- smt_gain /= weight;
-
- return smt_gain;
-}
-
-unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
-{
- return default_scale_smt_power(sd, cpu);
-}
-
-unsigned long scale_rt_power(int cpu)
-{
- struct rq *rq = cpu_rq(cpu);
- u64 total, available;
-
- sched_avg_update(rq);
-
- total = sched_avg_period() + (rq->clock - rq->age_stamp);
- available = total - rq->rt_avg;
-
- if (unlikely((s64)total < SCHED_LOAD_SCALE))
- total = SCHED_LOAD_SCALE;
-
- total >>= SCHED_LOAD_SHIFT;
-
- return div_u64(available, total);
-}
-
-static void update_cpu_power(struct sched_domain *sd, int cpu)
-{
- unsigned long weight = cpumask_weight(sched_domain_span(sd));
- unsigned long power = SCHED_LOAD_SCALE;
- struct sched_group *sdg = sd->groups;
-
- if (sched_feat(ARCH_POWER))
- power *= arch_scale_freq_power(sd, cpu);
- else
- power *= default_scale_freq_power(sd, cpu);
-
- power >>= SCHED_LOAD_SHIFT;
-
- if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
- if (sched_feat(ARCH_POWER))
- power *= arch_scale_smt_power(sd, cpu);
- else
- power *= default_scale_smt_power(sd, cpu);
-
- power >>= SCHED_LOAD_SHIFT;
- }
-
- power *= scale_rt_power(cpu);
- power >>= SCHED_LOAD_SHIFT;
-
- if (!power)
- power = 1;
-
- sdg->cpu_power = power;
-}
-
-static void update_group_power(struct sched_domain *sd, int cpu)
-{
- struct sched_domain *child = sd->child;
- struct sched_group *group, *sdg = sd->groups;
- unsigned long power;
-
- if (!child) {
- update_cpu_power(sd, cpu);
- return;
- }
-
- power = 0;
-
- group = child->groups;
- do {
- power += group->cpu_power;
- group = group->next;
- } while (group != child->groups);
-
- sdg->cpu_power = power;
-}
-
-/**
- * update_sg_lb_stats - Update sched_group's statistics for load balancing.
- * @sd: The sched_domain whose statistics are to be updated.
- * @group: sched_group whose statistics are to be updated.
- * @this_cpu: Cpu for which load balance is currently performed.
- * @idle: Idle status of this_cpu
- * @load_idx: Load index of sched_domain of this_cpu for load calc.
- * @sd_idle: Idle status of the sched_domain containing group.
- * @local_group: Does group contain this_cpu.
- * @cpus: Set of cpus considered for load balancing.
- * @balance: Should we balance.
- * @sgs: variable to hold the statistics for this group.
- */
-static inline void update_sg_lb_stats(struct sched_domain *sd,
- struct sched_group *group, int this_cpu,
- enum cpu_idle_type idle, int load_idx, int *sd_idle,
- int local_group, const struct cpumask *cpus,
- int *balance, struct sg_lb_stats *sgs)
-{
- unsigned long load, max_cpu_load, min_cpu_load;
- int i;
- unsigned int balance_cpu = -1, first_idle_cpu = 0;
- unsigned long sum_avg_load_per_task;
- unsigned long avg_load_per_task;
-
- if (local_group) {
- balance_cpu = group_first_cpu(group);
- if (balance_cpu == this_cpu)
- update_group_power(sd, this_cpu);
- }
-
- /* Tally up the load of all CPUs in the group */
- sum_avg_load_per_task = avg_load_per_task = 0;
- max_cpu_load = 0;
- min_cpu_load = ~0UL;
-
- for_each_cpu_and(i, sched_group_cpus(group), cpus) {
- struct rq *rq = cpu_rq(i);
-
- if (*sd_idle && rq->nr_running)
- *sd_idle = 0;
-
- /* Bias balancing toward cpus of our domain */
- if (local_group) {
- if (idle_cpu(i) && !first_idle_cpu) {
- first_idle_cpu = 1;
- balance_cpu = i;
- }
-
- load = target_load(i, load_idx);
- } else {
- load = source_load(i, load_idx);
- if (load > max_cpu_load)
- max_cpu_load = load;
- if (min_cpu_load > load)
- min_cpu_load = load;
- }
-
- sgs->group_load += load;
- sgs->sum_nr_running += rq->nr_running;
- sgs->sum_weighted_load += weighted_cpuload(i);
-
- sum_avg_load_per_task += cpu_avg_load_per_task(i);
- }
-
- /*
- * First idle cpu or the first cpu(busiest) in this sched group
- * is eligible for doing load balancing at this and above
- * domains. In the newly idle case, we will allow all the cpu's
- * to do the newly idle load balance.
- */
- if (idle != CPU_NEWLY_IDLE && local_group &&
- balance_cpu != this_cpu && balance) {
- *balance = 0;
- return;
- }
-
- /* Adjust by relative CPU power of the group */
- sgs->avg_load = (sgs->group_load * SCHED_LOAD_SCALE) / group->cpu_power;
-
-
- /*
- * Consider the group unbalanced when the imbalance is larger
- * than the average weight of two tasks.
- *
- * APZ: with cgroup the avg task weight can vary wildly and
- * might not be a suitable number - should we keep a
- * normalized nr_running number somewhere that negates
- * the hierarchy?
- */
- avg_load_per_task = (sum_avg_load_per_task * SCHED_LOAD_SCALE) /
- group->cpu_power;
-
- if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
- sgs->group_imb = 1;
-
- sgs->group_capacity =
- DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE);
-}
-
-/**
- * update_sd_lb_stats - Update sched_group's statistics for load balancing.
- * @sd: sched_domain whose statistics are to be updated.
- * @this_cpu: Cpu for which load balance is currently performed.
- * @idle: Idle status of this_cpu
- * @sd_idle: Idle status of the sched_domain containing group.
- * @cpus: Set of cpus considered for load balancing.
- * @balance: Should we balance.
- * @sds: variable to hold the statistics for this sched_domain.
- */
-static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
- enum cpu_idle_type idle, int *sd_idle,
- const struct cpumask *cpus, int *balance,
- struct sd_lb_stats *sds)
-{
- struct sched_domain *child = sd->child;
- struct sched_group *group = sd->groups;
- struct sg_lb_stats sgs;
- int load_idx, prefer_sibling = 0;
-
- if (child && child->flags & SD_PREFER_SIBLING)
- prefer_sibling = 1;
-
- init_sd_power_savings_stats(sd, sds, idle);
- load_idx = get_sd_load_idx(sd, idle);
-
- do {
- int local_group;
-
- local_group = cpumask_test_cpu(this_cpu,
- sched_group_cpus(group));
- memset(&sgs, 0, sizeof(sgs));
- update_sg_lb_stats(sd, group, this_cpu, idle, load_idx, sd_idle,
- local_group, cpus, balance, &sgs);
-
- if (local_group && balance && !(*balance))
- return;
-
- sds->total_load += sgs.group_load;
- sds->total_pwr += group->cpu_power;
-
- /*
- * In case the child domain prefers tasks go to siblings
- * first, lower the group capacity to one so that we'll try
- * and move all the excess tasks away.
- */
- if (prefer_sibling)
- sgs.group_capacity = min(sgs.group_capacity, 1UL);
-
- if (local_group) {
- sds->this_load = sgs.avg_load;
- sds->this = group;
- sds->this_nr_running = sgs.sum_nr_running;
- sds->this_load_per_task = sgs.sum_weighted_load;
- } else if (sgs.avg_load > sds->max_load &&
- (sgs.sum_nr_running > sgs.group_capacity ||
- sgs.group_imb)) {
- sds->max_load = sgs.avg_load;
- sds->busiest = group;
- sds->busiest_nr_running = sgs.sum_nr_running;
- sds->busiest_load_per_task = sgs.sum_weighted_load;
- sds->group_imb = sgs.group_imb;
- }
-
- update_sd_power_savings_stats(group, sds, local_group, &sgs);
- group = group->next;
- } while (group != sd->groups);
-}
-
-/**
- * fix_small_imbalance - Calculate the minor imbalance that exists
- * amongst the groups of a sched_domain, during
- * load balancing.
- * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
- * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
- * @imbalance: Variable to store the imbalance.
- */
-static inline void fix_small_imbalance(struct sd_lb_stats *sds,
- int this_cpu, unsigned long *imbalance)
-{
- unsigned long tmp, pwr_now = 0, pwr_move = 0;
- unsigned int imbn = 2;
-
- if (sds->this_nr_running) {
- sds->this_load_per_task /= sds->this_nr_running;
- if (sds->busiest_load_per_task >
- sds->this_load_per_task)
- imbn = 1;
- } else
- sds->this_load_per_task =
- cpu_avg_load_per_task(this_cpu);
-
- if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
- sds->busiest_load_per_task * imbn) {
- *imbalance = sds->busiest_load_per_task;
- return;
- }
-
- /*
- * OK, we don't have enough imbalance to justify moving tasks,
- * however we may be able to increase total CPU power used by
- * moving them.
- */
-
- pwr_now += sds->busiest->cpu_power *
- 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;
-
- /* Amount of load we'd subtract */
- tmp = (sds->busiest_load_per_task * SCHED_LOAD_SCALE) /
- sds->busiest->cpu_power;
- if (sds->max_load > tmp)
- pwr_move += sds->busiest->cpu_power *
- min(sds->busiest_load_per_task, sds->max_load - tmp);
-
- /* Amount of load we'd add */
- if (sds->max_load * sds->busiest->cpu_power <
- sds->busiest_load_per_task * SCHED_LOAD_SCALE)
- tmp = (sds->max_load * sds->busiest->cpu_power) /
- sds->this->cpu_power;
- else
- tmp = (sds->busiest_load_per_task * SCHED_LOAD_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;
-
- /* Move if we gain throughput */
- if (pwr_move > pwr_now)
- *imbalance = sds->busiest_load_per_task;
-}
-
-/**
- * calculate_imbalance - Calculate the amount of imbalance present within the
- * groups of a given sched_domain during load balance.
- * @sds: statistics of the sched_domain whose imbalance is to be calculated.
- * @this_cpu: Cpu for which currently load balance is being performed.
- * @imbalance: The variable to store the imbalance.
- */
-static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
- unsigned long *imbalance)
-{
- unsigned long max_pull;
- /*
- * In the presence of smp nice balancing, certain scenarios can have
- * max load less than avg load(as we skip the groups at or below
- * its cpu_power, while calculating max_load..)
- */
- if (sds->max_load < sds->avg_load) {
- *imbalance = 0;
- return fix_small_imbalance(sds, this_cpu, imbalance);
- }
-
- /* Don't want to pull so many tasks that a group would go idle */
- max_pull = min(sds->max_load - sds->avg_load,
- sds->max_load - sds->busiest_load_per_task);
-
- /* 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;
-
- /*
- * if *imbalance is less than the average load per runnable task
- * there is no gaurantee that any tasks will be moved so we'll have
- * a think about bumping its value to force at least one task to be
- * moved
- */
- if (*imbalance < sds->busiest_load_per_task)
- return fix_small_imbalance(sds, this_cpu, imbalance);
-
-}
-/******* find_busiest_group() helpers end here *********************/
-
-/**
- * find_busiest_group - Returns the busiest group within the sched_domain
- * if there is an imbalance. If there isn't an imbalance, and
- * the user has opted for power-savings, it returns a group whose
- * CPUs can be put to idle by rebalancing those tasks elsewhere, if
- * such a group exists.
- *
- * Also calculates the amount of weighted load which should be moved
- * to restore balance.
- *
- * @sd: The sched_domain whose busiest group is to be returned.
- * @this_cpu: The cpu for which load balancing is currently being performed.
- * @imbalance: Variable which stores amount of weighted load which should
- * be moved to restore balance/put a group to idle.
- * @idle: The idle status of this_cpu.
- * @sd_idle: The idleness of sd
- * @cpus: The set of CPUs under consideration for load-balancing.
- * @balance: Pointer to a variable indicating if this_cpu
- * is the appropriate cpu to perform load balancing at this_level.
- *
- * Returns: - the busiest group if imbalance exists.
- * - If no imbalance and user has opted for power-savings balance,
- * return the least loaded group whose CPUs can be
- * put to idle by rebalancing its tasks onto our group.
- */
-static struct sched_group *
-find_busiest_group(struct sched_domain *sd, int this_cpu,
- unsigned long *imbalance, enum cpu_idle_type idle,
- int *sd_idle, const struct cpumask *cpus, int *balance)
-{
- struct sd_lb_stats sds;
-
- memset(&sds, 0, sizeof(sds));
-
- /*
- * Compute the various statistics relavent for load balancing at
- * this level.
- */
- update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
- balance, &sds);
-
- /* Cases where imbalance does not exist from POV of this_cpu */
- /* 1) this_cpu is not the appropriate cpu to perform load balancing
- * at this level.
- * 2) There is no busy sibling group to pull from.
- * 3) This group is the busiest group.
- * 4) This group is more busy than the avg busieness at this
- * sched_domain.
- * 5) The imbalance is within the specified limit.
- * 6) Any rebalance would lead to ping-pong
- */
- if (balance && !(*balance))
- goto ret;
-
- if (!sds.busiest || sds.busiest_nr_running == 0)
- goto out_balanced;
-
- if (sds.this_load >= sds.max_load)
- goto out_balanced;
-
- sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
-
- if (sds.this_load >= sds.avg_load)
- goto out_balanced;
-
- if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
- goto out_balanced;
-
- sds.busiest_load_per_task /= sds.busiest_nr_running;
- if (sds.group_imb)
- sds.busiest_load_per_task =
- min(sds.busiest_load_per_task, sds.avg_load);
-
- /*
- * We're trying to get all the cpus to the average_load, so we don't
- * want to push ourselves above the average load, nor do we wish to
- * reduce the max loaded cpu below the average load, as either of these
- * actions would just result in more rebalancing later, and ping-pong
- * tasks around. Thus we look for the minimum possible imbalance.
- * Negative imbalances (*we* are more loaded than anyone else) will
- * be counted as no imbalance for these purposes -- we can't fix that
- * by pulling tasks to us. Be careful of negative numbers as they'll
- * appear as very large values with unsigned longs.
- */
- if (sds.max_load <= sds.busiest_load_per_task)
- goto out_balanced;
-
- /* Looks like there is an imbalance. Compute it */
- calculate_imbalance(&sds, this_cpu, imbalance);
- return sds.busiest;
-
-out_balanced:
- /*
- * There is no obvious imbalance. But check if we can do some balancing
- * to save power.
- */
- if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
- return sds.busiest;
-ret:
- *imbalance = 0;
- return NULL;
-}
-
-/*
- * find_busiest_queue - find the busiest runqueue among the cpus in group.
- */
-static struct rq *
-find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
- unsigned long imbalance, const struct cpumask *cpus)
-{
- struct rq *busiest = NULL, *rq;
- unsigned long max_load = 0;
- int i;
-
- 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 wl;
-
- if (!cpumask_test_cpu(i, cpus))
- continue;
-
- rq = cpu_rq(i);
- wl = weighted_cpuload(i);
-
- /*
- * When comparing with imbalance, use weighted_cpuload()
- * which is not scaled with the cpu power.
- */
- if (capacity && rq->nr_running == 1 && wl > imbalance)
- continue;
-
- /*
- * For the load comparisons with the other cpu's, consider
- * the weighted_cpuload() scaled with the cpu power, so that
- * the load can be moved away from the cpu that is potentially
- * running at a lower capacity.
- */
- wl = (wl * SCHED_LOAD_SCALE) / power;
-
- if (wl > max_load) {
- max_load = wl;
- busiest = rq;
- }
- }
-
- return busiest;
-}
-
-/*
- * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
- * so long as it is large enough.
- */
-#define MAX_PINNED_INTERVAL 512
-
-/* Working cpumask for load_balance and load_balance_newidle. */
-static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
-
-/*
- * Check this_cpu to ensure it is balanced within domain. Attempt to move
- * tasks if there is an imbalance.
- */
-static int load_balance(int this_cpu, struct rq *this_rq,
- struct sched_domain *sd, enum cpu_idle_type idle,
- int *balance)
-{
- int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
- struct sched_group *group;
- unsigned long imbalance;
- struct rq *busiest;
- unsigned long flags;
- struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
-
- cpumask_copy(cpus, cpu_active_mask);
-
- /*
- * When power savings policy is enabled for the parent domain, idle
- * sibling can pick up load irrespective of busy siblings. In this case,
- * let the state of idle sibling percolate up as CPU_IDLE, instead of
- * portraying it as CPU_NOT_IDLE.
- */
- if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- sd_idle = 1;
-
- schedstat_inc(sd, lb_count[idle]);
-
-redo:
- update_shares(sd);
- group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
- cpus, balance);
-
- if (*balance == 0)
- goto out_balanced;
-
- if (!group) {
- schedstat_inc(sd, lb_nobusyg[idle]);
- goto out_balanced;
- }
-
- busiest = find_busiest_queue(group, idle, imbalance, cpus);
- if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[idle]);
- goto out_balanced;
- }
-
- BUG_ON(busiest == this_rq);
-
- schedstat_add(sd, lb_imbalance[idle], imbalance);
-
- ld_moved = 0;
- if (busiest->nr_running > 1) {
- /*
- * Attempt to move tasks. If find_busiest_group has found
- * an imbalance but busiest->nr_running <= 1, the group is
- * still unbalanced. ld_moved simply stays zero, so it is
- * correctly treated as an imbalance.
- */
- local_irq_save(flags);
- double_rq_lock(this_rq, busiest);
- ld_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, idle, &all_pinned);
- double_rq_unlock(this_rq, busiest);
- local_irq_restore(flags);
-
- /*
- * some other cpu did the load balance for us.
- */
- if (ld_moved && this_cpu != smp_processor_id())
- resched_cpu(this_cpu);
-
- /* All tasks on this runqueue were pinned by CPU affinity */
- if (unlikely(all_pinned)) {
- cpumask_clear_cpu(cpu_of(busiest), cpus);
- if (!cpumask_empty(cpus))
- goto redo;
- goto out_balanced;
- }
- }
-
- if (!ld_moved) {
- schedstat_inc(sd, lb_failed[idle]);
- sd->nr_balance_failed++;
-
- if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
-
- raw_spin_lock_irqsave(&busiest->lock, flags);
-
- /* don't kick the migration_thread, if the curr
- * task on busiest cpu can't be moved to this_cpu
- */
- if (!cpumask_test_cpu(this_cpu,
- &busiest->curr->cpus_allowed)) {
- raw_spin_unlock_irqrestore(&busiest->lock,
- flags);
- all_pinned = 1;
- goto out_one_pinned;
- }
-
- if (!busiest->active_balance) {
- busiest->active_balance = 1;
- busiest->push_cpu = this_cpu;
- active_balance = 1;
- }
- raw_spin_unlock_irqrestore(&busiest->lock, flags);
- if (active_balance)
- wake_up_process(busiest->migration_thread);
-
- /*
- * We've kicked active balancing, reset the failure
- * counter.
- */
- sd->nr_balance_failed = sd->cache_nice_tries+1;
- }
- } else
- sd->nr_balance_failed = 0;
-
- if (likely(!active_balance)) {
- /* We were unbalanced, so reset the balancing interval */
- sd->balance_interval = sd->min_interval;
- } else {
- /*
- * If we've begun active balancing, start to back off. This
- * case may not be covered by the all_pinned logic if there
- * is only 1 task on the busy runqueue (because we don't call
- * move_tasks).
- */
- if (sd->balance_interval < sd->max_interval)
- sd->balance_interval *= 2;
- }
-
- if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- ld_moved = -1;
-
- goto out;
-
-out_balanced:
- schedstat_inc(sd, lb_balanced[idle]);
-
- sd->nr_balance_failed = 0;
-
-out_one_pinned:
- /* tune up the balancing interval */
- if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
- (sd->balance_interval < sd->max_interval))
- sd->balance_interval *= 2;
-
- if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- ld_moved = -1;
- else
- ld_moved = 0;
-out:
- if (ld_moved)
- update_shares(sd);
- return ld_moved;
-}
-
-/*
- * Check this_cpu to ensure it is balanced within domain. Attempt to move
- * tasks if there is an imbalance.
- *
- * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
- * this_rq is locked.
- */
-static int
-load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
-{
- struct sched_group *group;
- struct rq *busiest = NULL;
- unsigned long imbalance;
- int ld_moved = 0;
- int sd_idle = 0;
- int all_pinned = 0;
- struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
-
- cpumask_copy(cpus, cpu_active_mask);
-
- /*
- * When power savings policy is enabled for the parent domain, idle
- * sibling can pick up load irrespective of busy siblings. In this case,
- * let the state of idle sibling percolate up as IDLE, instead of
- * portraying it as CPU_NOT_IDLE.
- */
- if (sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- sd_idle = 1;
-
- schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
-redo:
- update_shares_locked(this_rq, sd);
- group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
- &sd_idle, cpus, NULL);
- if (!group) {
- schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
- goto out_balanced;
- }
-
- busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
- if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
- goto out_balanced;
- }
-
- BUG_ON(busiest == this_rq);
-
- schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
-
- ld_moved = 0;
- if (busiest->nr_running > 1) {
- /* Attempt to move tasks */
- double_lock_balance(this_rq, busiest);
- /* this_rq->clock is already updated */
- update_rq_clock(busiest);
- ld_moved = move_tasks(this_rq, this_cpu, busiest,
- imbalance, sd, CPU_NEWLY_IDLE,
- &all_pinned);
- double_unlock_balance(this_rq, busiest);
-
- if (unlikely(all_pinned)) {
- cpumask_clear_cpu(cpu_of(busiest), cpus);
- if (!cpumask_empty(cpus))
- goto redo;
- }
- }
-
- if (!ld_moved) {
- int active_balance = 0;
-
- schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
- if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- return -1;
-
- if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
- return -1;
-
- if (sd->nr_balance_failed++ < 2)
- return -1;
-
- /*
- * The only task running in a non-idle cpu can be moved to this
- * cpu in an attempt to completely freeup the other CPU
- * package. The same method used to move task in load_balance()
- * have been extended for load_balance_newidle() to speedup
- * consolidation at sched_mc=POWERSAVINGS_BALANCE_WAKEUP (2)
- *
- * The package power saving logic comes from
- * find_busiest_group(). If there are no imbalance, then
- * f_b_g() will return NULL. However when sched_mc={1,2} then
- * f_b_g() will select a group from which a running task may be
- * pulled to this cpu in order to make the other package idle.
- * If there is no opportunity to make a package idle and if
- * there are no imbalance, then f_b_g() will return NULL and no
- * action will be taken in load_balance_newidle().
- *
- * Under normal task pull operation due to imbalance, there
- * will be more than one task in the source run queue and
- * move_tasks() will succeed. ld_moved will be true and this
- * active balance code will not be triggered.
- */
-
- /* Lock busiest in correct order while this_rq is held */
- double_lock_balance(this_rq, busiest);
-
- /*
- * don't kick the migration_thread, if the curr
- * task on busiest cpu can't be moved to this_cpu
- */
- if (!cpumask_test_cpu(this_cpu, &busiest->curr->cpus_allowed)) {
- double_unlock_balance(this_rq, busiest);
- all_pinned = 1;
- return ld_moved;
- }
-
- if (!busiest->active_balance) {
- busiest->active_balance = 1;
- busiest->push_cpu = this_cpu;
- active_balance = 1;
- }
-
- double_unlock_balance(this_rq, busiest);
- /*
- * Should not call ttwu while holding a rq->lock
- */
- raw_spin_unlock(&this_rq->lock);
- if (active_balance)
- wake_up_process(busiest->migration_thread);
- raw_spin_lock(&this_rq->lock);
-
- } else
- sd->nr_balance_failed = 0;
-
- update_shares_locked(this_rq, sd);
- return ld_moved;
-
-out_balanced:
- schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
- if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
- !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
- return -1;
- sd->nr_balance_failed = 0;
-
- return 0;
-}
-
-/*
- * idle_balance is called by schedule() if this_cpu is about to become
- * idle. Attempts to pull tasks from other CPUs.
- */
-static void idle_balance(int this_cpu, struct rq *this_rq)
-{
- struct sched_domain *sd;
- int pulled_task = 0;
- unsigned long next_balance = jiffies + HZ;
-
- this_rq->idle_stamp = this_rq->clock;
-
- if (this_rq->avg_idle < sysctl_sched_migration_cost)
- return;
-
- for_each_domain(this_cpu, sd) {
- unsigned long interval;
-
- if (!(sd->flags & SD_LOAD_BALANCE))
- continue;
-
- if (sd->flags & SD_BALANCE_NEWIDLE)
- /* If we've pulled tasks over stop searching: */
- pulled_task = load_balance_newidle(this_cpu, this_rq,
- sd);
-
- interval = msecs_to_jiffies(sd->balance_interval);
- if (time_after(next_balance, sd->last_balance + interval))
- next_balance = sd->last_balance + interval;
- if (pulled_task) {
- this_rq->idle_stamp = 0;
- break;
- }
- }
- if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
- /*
- * We are going idle. next_balance may be set based on
- * a busy processor. So reset next_balance.
- */
- this_rq->next_balance = next_balance;
- }
-}
-
-/*
- * active_load_balance is run by migration threads. It pushes running tasks
- * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
- * running on each physical CPU where possible, and avoids physical /
- * logical imbalances.
- *
- * Called with busiest_rq locked.
- */
-static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
-{
- int target_cpu = busiest_rq->push_cpu;
- struct sched_domain *sd;
- struct rq *target_rq;
-
- /* Is there any task to move? */
- if (busiest_rq->nr_running <= 1)