diff options
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 286 |
1 files changed, 64 insertions, 222 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 716cfc8e099e..f864b751fd19 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -406,34 +406,23 @@ struct cfs_rq { struct task_group *tg; /* group that "owns" this runqueue */ #ifdef CONFIG_SMP - unsigned long task_weight; - unsigned long shares; /* - * We need space to build a sched_domain wide view of the full task - * group tree, in order to avoid depending on dynamic memory allocation - * during the load balancing we place this in the per cpu task group - * hierarchy. This limits the load balancing to one instance per cpu, - * but more should not be needed anyway. + * the part of load.weight contributed by tasks */ - struct aggregate_struct { - /* - * load = weight(cpus) * f(tg) - * - * Where f(tg) is the recursive weight fraction assigned to - * this group. - */ - unsigned long load; + unsigned long task_weight; - /* - * part of the group weight distributed to this span. - */ - unsigned long shares; + /* + * h_load = weight * f(tg) + * + * Where f(tg) is the recursive weight fraction assigned to + * this group. + */ + unsigned long h_load; - /* - * The sum of all runqueue weights within this span. - */ - unsigned long rq_weight; - } aggregate; + /* + * this cpu's part of tg->shares + */ + unsigned long shares; #endif #endif }; @@ -1443,47 +1432,14 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); #ifdef CONFIG_FAIR_GROUP_SCHED -/* - * Group load balancing. - * - * We calculate a few balance domain wide aggregate numbers; load and weight. - * Given the pictures below, and assuming each item has equal weight: - * - * root 1 - thread - * / | \ A - group - * A 1 B - * /|\ / \ - * C 2 D 3 4 - * | | - * 5 6 - * - * load: - * A and B get 1/3-rd of the total load. C and D get 1/3-rd of A's 1/3-rd, - * which equals 1/9-th of the total load. - * - * shares: - * The weight of this group on the selected cpus. - * - * rq_weight: - * Direct sum of all the cpu's their rq weight, e.g. A would get 3 while - * B would get 2. - */ - -static inline struct aggregate_struct * -aggregate(struct task_group *tg, int cpu) -{ - return &tg->cfs_rq[cpu]->aggregate; -} - -typedef void (*aggregate_func)(struct task_group *, int, struct sched_domain *); +typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *); /* * Iterate the full tree, calling @down when first entering a node and @up when * leaving it for the final time. */ -static -void aggregate_walk_tree(aggregate_func down, aggregate_func up, - int cpu, struct sched_domain *sd) +static void +walk_tg_tree(tg_visitor down, tg_visitor up, int cpu, struct sched_domain *sd) { struct task_group *parent, *child; @@ -1507,72 +1463,6 @@ up: rcu_read_unlock(); } -/* - * Calculate the aggregate runqueue weight. - */ -static void -aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long rq_weight = 0; - int i; - - for_each_cpu_mask(i, sd->span) - rq_weight += tg->cfs_rq[i]->load.weight; - - aggregate(tg, cpu)->rq_weight = rq_weight; -} - -/* - * Compute the weight of this group on the given cpus. - */ -static void -aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long shares = 0; - int i; - - for_each_cpu_mask(i, sd->span) - shares += tg->cfs_rq[i]->shares; - - if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares) - shares = tg->shares; - - if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) - shares = tg->shares; - - aggregate(tg, cpu)->shares = shares; -} - -/* - * Compute the load fraction assigned to this group, relies on the aggregate - * weight and this group's parent's load, i.e. top-down. - */ -static void -aggregate_group_load(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long load; - - if (!tg->parent) { - int i; - - load = 0; - for_each_cpu_mask(i, sd->span) - load += cpu_rq(i)->load.weight; - - } else { - load = aggregate(tg->parent, cpu)->load; - - /* - * shares is our weight in the parent's rq so - * shares/parent->rq_weight gives our fraction of the load - */ - load *= aggregate(tg, cpu)->shares; - load /= aggregate(tg->parent, cpu)->rq_weight + 1; - } - - aggregate(tg, cpu)->load = load; -} - static void __set_se_shares(struct sched_entity *se, unsigned long shares); /* @@ -1580,16 +1470,16 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares); */ static void __update_group_shares_cpu(struct task_group *tg, int cpu, - struct sched_domain *sd, int tcpu) + unsigned long sd_shares, unsigned long sd_rq_weight) { int boost = 0; unsigned long shares; unsigned long rq_weight; - if (!tg->se[tcpu]) + if (!tg->se[cpu]) return; - rq_weight = tg->cfs_rq[tcpu]->load.weight; + rq_weight = tg->cfs_rq[cpu]->load.weight; /* * If there are currently no tasks on the cpu pretend there is one of @@ -1601,124 +1491,97 @@ __update_group_shares_cpu(struct task_group *tg, int cpu, rq_weight = NICE_0_LOAD; } + if (unlikely(rq_weight > sd_rq_weight)) + rq_weight = sd_rq_weight; + /* * \Sum shares * rq_weight * shares = ----------------------- * \Sum rq_weight * */ - shares = aggregate(tg, cpu)->shares * rq_weight; - shares /= aggregate(tg, cpu)->rq_weight + 1; + shares = (sd_shares * rq_weight) / (sd_rq_weight + 1); /* * record the actual number of shares, not the boosted amount. */ - tg->cfs_rq[tcpu]->shares = boost ? 0 : shares; + tg->cfs_rq[cpu]->shares = boost ? 0 : shares; if (shares < MIN_SHARES) shares = MIN_SHARES; else if (shares > MAX_SHARES) shares = MAX_SHARES; - __set_se_shares(tg->se[tcpu], shares); + __set_se_shares(tg->se[cpu], shares); } /* - * Re-adjust the weights on the cpu the task came from and on the cpu the - * task went to. + * Re-compute the task group their per cpu shares over the given domain. + * This needs to be done in a bottom-up fashion because the rq weight of a + * parent group depends on the shares of its child groups. */ static void -__move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, - int scpu, int dcpu) +tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd) { - __update_group_shares_cpu(tg, cpu, sd, scpu); - __update_group_shares_cpu(tg, cpu, sd, dcpu); -} + unsigned long rq_weight = 0; + unsigned long shares = 0; + int i; -/* - * Because changing a group's shares changes the weight of the super-group - * we need to walk up the tree and change all shares until we hit the root. - */ -static void -move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, - int scpu, int dcpu) -{ - while (tg) { - __move_group_shares(tg, cpu, sd, scpu, dcpu); - tg = tg->parent; + for_each_cpu_mask(i, sd->span) { + rq_weight += tg->cfs_rq[i]->load.weight; + shares += tg->cfs_rq[i]->shares; } -} -static void -aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - int i; + if ((!shares && rq_weight) || shares > tg->shares) + shares = tg->shares; + + if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) + shares = tg->shares; for_each_cpu_mask(i, sd->span) { struct rq *rq = cpu_rq(i); unsigned long flags; spin_lock_irqsave(&rq->lock, flags); - __update_group_shares_cpu(tg, cpu, sd, i); + __update_group_shares_cpu(tg, i, shares, rq_weight); spin_unlock_irqrestore(&rq->lock, flags); } - - aggregate_group_shares(tg, cpu, sd); } /* - * Calculate the accumulative weight and recursive load of each task group - * while walking down the tree. + * Compute the cpu's hierarchical load factor for each task group. + * This needs to be done in a top-down fashion because the load of a child + * group is a fraction of its parents load. */ static void -aggregate_get_down(struct task_group *tg, int cpu, struct sched_domain *sd) +tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd) { - aggregate_group_weight(tg, cpu, sd); - aggregate_group_shares(tg, cpu, sd); - aggregate_group_load(tg, cpu, sd); -} - -/* - * Rebalance the cpu shares while walking back up the tree. - */ -static void -aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - aggregate_group_set_shares(tg, cpu, sd); -} - -static void -aggregate_get_nop(struct task_group *tg, int cpu, struct sched_domain *sd) -{ -} - -static DEFINE_PER_CPU(spinlock_t, aggregate_lock); + unsigned long load; -static void __init init_aggregate(void) -{ - int i; + if (!tg->parent) { + load = cpu_rq(cpu)->load.weight; + } else { + load = tg->parent->cfs_rq[cpu]->h_load; + load *= tg->cfs_rq[cpu]->shares; + load /= tg->parent->cfs_rq[cpu]->load.weight + 1; + } - for_each_possible_cpu(i) - spin_lock_init(&per_cpu(aggregate_lock, i)); + tg->cfs_rq[cpu]->h_load = load; } -static int get_aggregate(int cpu, struct sched_domain *sd) +static void +tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd) { - if (!spin_trylock(&per_cpu(aggregate_lock, cpu))) - return 0; - - aggregate_walk_tree(aggregate_get_down, aggregate_get_up, cpu, sd); - return 1; } -static void update_aggregate(int cpu, struct sched_domain *sd) +static void update_shares(struct sched_domain *sd) { - aggregate_walk_tree(aggregate_get_down, aggregate_get_nop, cpu, sd); + walk_tg_tree(tg_nop, tg_shares_up, 0, sd); } -static void put_aggregate(int cpu, struct sched_domain *sd) +static void update_h_load(int cpu) { - spin_unlock(&per_cpu(aggregate_lock, cpu)); + walk_tg_tree(tg_load_down, tg_nop, cpu, NULL); } static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) @@ -1728,22 +1591,10 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) #else -static inline void init_aggregate(void) -{ -} - -static inline int get_aggregate(int cpu, struct sched_domain *sd) -{ - return 0; -} - -static inline void update_aggregate(int cpu, struct sched_domain *sd) +static inline void update_shares(struct sched_domain *sd) { } -static inline void put_aggregate(int cpu, struct sched_domain *sd) -{ -} #endif #endif @@ -2172,12 +2023,6 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) int load_idx = sd->forkexec_idx; int imbalance = 100 + (sd->imbalance_pct-100)/2; - /* - * now that we have both rqs locked the rq weight won't change - * anymore - so update the stats. - */ - update_aggregate(this_cpu, sd); - do { unsigned long load, avg_load; int local_group; @@ -3521,12 +3366,9 @@ static int load_balance(int this_cpu, struct rq *this_rq, unsigned long imbalance; struct rq *busiest; unsigned long flags; - int unlock_aggregate; cpus_setall(*cpus); - unlock_aggregate = get_aggregate(this_cpu, sd); - /* * When power savings policy is enabled for the parent domain, idle * sibling can pick up load irrespective of busy siblings. In this case, @@ -3540,6 +3382,7 @@ static int load_balance(int this_cpu, struct rq *this_rq, schedstat_inc(sd, lb_count[idle]); redo: + update_shares(sd); group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, cpus, balance); @@ -3663,8 +3506,8 @@ out_one_pinned: else ld_moved = 0; out: - if (unlock_aggregate) - put_aggregate(this_cpu, sd); + if (ld_moved) + update_shares(sd); return ld_moved; } @@ -8019,7 +7862,6 @@ void __init sched_init(void) } #ifdef CONFIG_SMP - init_aggregate(); init_defrootdomain(); #endif |