diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/Kconfig.iosched | 6 | ||||
| -rw-r--r-- | block/bfq-cgroup.c | 1282 | ||||
| -rw-r--r-- | block/bfq-ioc.c | 6 | ||||
| -rw-r--r-- | block/bfq-iosched.c | 1083 | ||||
| -rw-r--r-- | block/bfq-sched.c | 209 | ||||
| -rw-r--r-- | block/bfq.h | 206 |
6 files changed, 1620 insertions, 1172 deletions
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched index 01da733dc..1fc1a4dc5 100644 --- a/block/Kconfig.iosched +++ b/block/Kconfig.iosched @@ -51,14 +51,12 @@ config IOSCHED_BFQ applications. If compiled built-in (saying Y here), BFQ can be configured to support hierarchical scheduling. -config CGROUP_BFQIO +config BFQ_GROUP_IOSCHED bool "BFQ hierarchical scheduling support" depends on CGROUPS && IOSCHED_BFQ=y default n ---help--- - Enable hierarchical scheduling in BFQ, using the cgroups - filesystem interface. The name of the subsystem will be - bfqio. + Enable hierarchical scheduling in BFQ, using the blkio controller. choice prompt "Default I/O scheduler" diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index 11e2f1d4e..bc34d7a2b 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -13,254 +13,480 @@ * file. */ -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED -static DEFINE_MUTEX(bfqio_mutex); +/* bfqg stats flags */ +enum bfqg_stats_flags { + BFQG_stats_waiting = 0, + BFQG_stats_idling, + BFQG_stats_empty, +}; -static bool bfqio_is_removed(struct bfqio_cgroup *bgrp) -{ - return bgrp ? !bgrp->online : false; -} +#define BFQG_FLAG_FNS(name) \ +static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \ +{ \ + stats->flags |= (1 << BFQG_stats_##name); \ +} \ +static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \ +{ \ + stats->flags &= ~(1 << BFQG_stats_##name); \ +} \ +static int bfqg_stats_##name(struct bfqg_stats *stats) \ +{ \ + return (stats->flags & (1 << BFQG_stats_##name)) != 0; \ +} \ -static struct bfqio_cgroup bfqio_root_cgroup = { - .weight = BFQ_DEFAULT_GRP_WEIGHT, - .ioprio = BFQ_DEFAULT_GRP_IOPRIO, - .ioprio_class = BFQ_DEFAULT_GRP_CLASS, -}; +BFQG_FLAG_FNS(waiting) +BFQG_FLAG_FNS(idling) +BFQG_FLAG_FNS(empty) +#undef BFQG_FLAG_FNS -static inline void bfq_init_entity(struct bfq_entity *entity, - struct bfq_group *bfqg) +/* This should be called with the queue_lock held. */ +static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats) { - entity->weight = entity->new_weight; - entity->orig_weight = entity->new_weight; - entity->ioprio = entity->new_ioprio; - entity->ioprio_class = entity->new_ioprio_class; - entity->parent = bfqg->my_entity; - entity->sched_data = &bfqg->sched_data; + unsigned long long now; + + if (!bfqg_stats_waiting(stats)) + return; + + now = sched_clock(); + if (time_after64(now, stats->start_group_wait_time)) + blkg_stat_add(&stats->group_wait_time, + now - stats->start_group_wait_time); + bfqg_stats_clear_waiting(stats); } -static struct bfqio_cgroup *css_to_bfqio(struct cgroup_subsys_state *css) +/* This should be called with the queue_lock held. */ +static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, + struct bfq_group *curr_bfqg) { - return css ? container_of(css, struct bfqio_cgroup, css) : NULL; + struct bfqg_stats *stats = &bfqg->stats; + + if (bfqg_stats_waiting(stats)) + return; + if (bfqg == curr_bfqg) + return; + stats->start_group_wait_time = sched_clock(); + bfqg_stats_mark_waiting(stats); } -/* - * Search the bfq_group for bfqd into the hash table (by now only a list) - * of bgrp. Must be called under rcu_read_lock(). - */ -static struct bfq_group *bfqio_lookup_group(struct bfqio_cgroup *bgrp, - struct bfq_data *bfqd) +/* This should be called with the queue_lock held. */ +static void bfqg_stats_end_empty_time(struct bfqg_stats *stats) { - struct bfq_group *bfqg; - void *key; + unsigned long long now; - hlist_for_each_entry_rcu(bfqg, &bgrp->group_data, group_node) { - key = rcu_dereference(bfqg->bfqd); - if (key == bfqd) - return bfqg; - } + if (!bfqg_stats_empty(stats)) + return; - return NULL; + now = sched_clock(); + if (time_after64(now, stats->start_empty_time)) + blkg_stat_add(&stats->empty_time, + now - stats->start_empty_time); + bfqg_stats_clear_empty(stats); } -static inline void bfq_group_init_entity(struct bfqio_cgroup *bgrp, - struct bfq_group *bfqg) +static void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { - struct bfq_entity *entity = &bfqg->entity; + blkg_stat_add(&bfqg->stats.dequeue, 1); +} + +static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + if (blkg_rwstat_total(&stats->queued)) + return; /* - * If the weight of the entity has never been set via the sysfs - * interface, then bgrp->weight == 0. In this case we initialize - * the weight from the current ioprio value. Otherwise, the group - * weight, if set, has priority over the ioprio value. + * group is already marked empty. This can happen if bfqq got new + * request in parent group and moved to this group while being added + * to service tree. Just ignore the event and move on. */ - if (bgrp->weight == 0) { - entity->new_weight = bfq_ioprio_to_weight(bgrp->ioprio); - entity->new_ioprio = bgrp->ioprio; - } else { - if (bgrp->weight < BFQ_MIN_WEIGHT || - bgrp->weight > BFQ_MAX_WEIGHT) { - printk(KERN_CRIT "bfq_group_init_entity: " - "bgrp->weight %d\n", bgrp->weight); - BUG(); - } - entity->new_weight = bgrp->weight; - entity->new_ioprio = bfq_weight_to_ioprio(bgrp->weight); + if (bfqg_stats_empty(stats)) + return; + + stats->start_empty_time = sched_clock(); + bfqg_stats_mark_empty(stats); +} + +static void bfqg_stats_update_idle_time(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + if (bfqg_stats_idling(stats)) { + unsigned long long now = sched_clock(); + + if (time_after64(now, stats->start_idle_time)) + blkg_stat_add(&stats->idle_time, + now - stats->start_idle_time); + bfqg_stats_clear_idling(stats); } - entity->orig_weight = entity->weight = entity->new_weight; - entity->ioprio = entity->new_ioprio; - entity->ioprio_class = entity->new_ioprio_class = bgrp->ioprio_class; - entity->my_sched_data = &bfqg->sched_data; - bfqg->active_entities = 0; } -static inline void bfq_group_set_parent(struct bfq_group *bfqg, - struct bfq_group *parent) +static void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { - struct bfq_entity *entity; + struct bfqg_stats *stats = &bfqg->stats; - BUG_ON(parent == NULL); - BUG_ON(bfqg == NULL); + stats->start_idle_time = sched_clock(); + bfqg_stats_mark_idling(stats); +} - entity = &bfqg->entity; - entity->parent = parent->my_entity; - entity->sched_data = &parent->sched_data; +static void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) +{ + struct bfqg_stats *stats = &bfqg->stats; + + blkg_stat_add(&stats->avg_queue_size_sum, + blkg_rwstat_total(&stats->queued)); + blkg_stat_add(&stats->avg_queue_size_samples, 1); + bfqg_stats_update_group_wait_time(stats); } -/** - * bfq_group_chain_alloc - allocate a chain of groups. - * @bfqd: queue descriptor. - * @css: the leaf cgroup_subsys_state this chain starts from. - * - * Allocate a chain of groups starting from the one belonging to - * @cgroup up to the root cgroup. Stop if a cgroup on the chain - * to the root has already an allocated group on @bfqd. +static struct blkcg_policy blkcg_policy_bfq; + +/* + * blk-cgroup policy-related handlers + * The following functions help in converting between blk-cgroup + * internal structures and BFQ-specific structures. */ -static struct bfq_group *bfq_group_chain_alloc(struct bfq_data *bfqd, - struct cgroup_subsys_state *css) + +static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd) { - struct bfqio_cgroup *bgrp; - struct bfq_group *bfqg, *prev = NULL, *leaf = NULL; + return pd ? container_of(pd, struct bfq_group, pd) : NULL; +} - for (; css != NULL; css = css->parent) { - bgrp = css_to_bfqio(css); +static struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg) +{ + return pd_to_blkg(&bfqg->pd); +} - bfqg = bfqio_lookup_group(bgrp, bfqd); - if (bfqg != NULL) { - /* - * All the cgroups in the path from there to the - * root must have a bfq_group for bfqd, so we don't - * need any more allocations. - */ - break; - } +static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg) +{ + return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq)); +} - bfqg = kzalloc(sizeof(*bfqg), GFP_ATOMIC); - if (bfqg == NULL) - goto cleanup; +/* + * bfq_group handlers + * The following functions help in navigating the bfq_group hierarchy + * by allowing to find the parent of a bfq_group or the bfq_group + * associated to a bfq_queue. + */ - bfq_group_init_entity(bgrp, bfqg); - bfqg->my_entity = &bfqg->entity; +static struct bfq_group *bfqg_parent(struct bfq_group *bfqg) +{ + struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent; - if (leaf == NULL) { - leaf = bfqg; - prev = leaf; - } else { - bfq_group_set_parent(prev, bfqg); - /* - * Build a list of allocated nodes using the bfqd - * filed, that is still unused and will be - * initialized only after the node will be - * connected. - */ - prev->bfqd = bfqg; - prev = bfqg; - } - } + return pblkg ? blkg_to_bfqg(pblkg) : NULL; +} - return leaf; +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq) +{ + struct bfq_entity *group_entity = bfqq->entity.parent; -cleanup: - while (leaf != NULL) { - prev = leaf; - leaf = leaf->bfqd; - kfree(prev); - } + return group_entity ? container_of(group_entity, struct bfq_group, + entity) : + bfqq->bfqd->root_group; +} + +/* + * The following two functions handle get and put of a bfq_group by + * wrapping the related blk-cgroup hooks. + */ - return NULL; +static void bfqg_get(struct bfq_group *bfqg) +{ + return blkg_get(bfqg_to_blkg(bfqg)); } -/** - * bfq_group_chain_link - link an allocated group chain to a cgroup - * hierarchy. - * @bfqd: the queue descriptor. - * @css: the leaf cgroup_subsys_state to start from. - * @leaf: the leaf group (to be associated to @cgroup). - * - * Try to link a chain of groups to a cgroup hierarchy, connecting the - * nodes bottom-up, so we can be sure that when we find a cgroup in the - * hierarchy that already as a group associated to @bfqd all the nodes - * in the path to the root cgroup have one too. - * - * On locking: the queue lock protects the hierarchy (there is a hierarchy - * per device) while the bfqio_cgroup lock protects the list of groups - * belonging to the same cgroup. +static void bfqg_put(struct bfq_group *bfqg) +{ + return blkg_put(bfqg_to_blkg(bfqg)); +} + +static void bfqg_stats_update_io_add(struct bfq_group *bfqg, + struct bfq_queue *bfqq, + int rw) +{ + blkg_rwstat_add(&bfqg->stats.queued, rw, 1); + bfqg_stats_end_empty_time(&bfqg->stats); + if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue)) + bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq)); +} + +static void bfqg_stats_update_io_remove(struct bfq_group *bfqg, int rw) +{ + blkg_rwstat_add(&bfqg->stats.queued, rw, -1); +} + +static void bfqg_stats_update_io_merged(struct bfq_group *bfqg, int rw) +{ + blkg_rwstat_add(&bfqg->stats.merged, rw, 1); +} + +static void bfqg_stats_update_dispatch(struct bfq_group *bfqg, + uint64_t bytes, int rw) +{ + blkg_stat_add(&bfqg->stats.sectors, bytes >> 9); + blkg_rwstat_add(&bfqg->stats.serviced, rw, 1); + blkg_rwstat_add(&bfqg->stats.service_bytes, rw, bytes); +} + +static void bfqg_stats_update_completion(struct bfq_group *bfqg, + uint64_t start_time, uint64_t io_start_time, int rw) +{ + struct bfqg_stats *stats = &bfqg->stats; + unsigned long long now = sched_clock(); + + if (time_after64(now, io_start_time)) + blkg_rwstat_add(&stats->service_time, rw, now - io_start_time); + if (time_after64(io_start_time, start_time)) + blkg_rwstat_add(&stats->wait_time, rw, + io_start_time - start_time); +} + +/* @stats = 0 */ +static void bfqg_stats_reset(struct bfqg_stats *stats) +{ + if (!stats) + return; + + /* queued stats shouldn't be cleared */ + blkg_rwstat_reset(&stats->service_bytes); + blkg_rwstat_reset(&stats->serviced); + blkg_rwstat_reset(&stats->merged); + blkg_rwstat_reset(&stats->service_time); + blkg_rwstat_reset(&stats->wait_time); + blkg_stat_reset(&stats->time); + blkg_stat_reset(&stats->unaccounted_time); + blkg_stat_reset(&stats->avg_queue_size_sum); + blkg_stat_reset(&stats->avg_queue_size_samples); + blkg_stat_reset(&stats->dequeue); + blkg_stat_reset(&stats->group_wait_time); + blkg_stat_reset(&stats->idle_time); + blkg_stat_reset(&stats->empty_time); +} + +/* @to += @from */ +static void bfqg_stats_merge(struct bfqg_stats *to, struct bfqg_stats *from) +{ + if (!to || !from) + return; + + /* queued stats shouldn't be cleared */ + blkg_rwstat_merge(&to->service_bytes, &from->service_bytes); + blkg_rwstat_merge(&to->serviced, &from->serviced); + blkg_rwstat_merge(&to->merged, &from->merged); + blkg_rwstat_merge(&to->service_time, &from->service_time); + blkg_rwstat_merge(&to->wait_time, &from->wait_time); + blkg_stat_merge(&from->time, &from->time); + blkg_stat_merge(&to->unaccounted_time, &from->unaccounted_time); + blkg_stat_merge(&to->avg_queue_size_sum, &from->avg_queue_size_sum); + blkg_stat_merge(&to->avg_queue_size_samples, &from->avg_queue_size_samples); + blkg_stat_merge(&to->dequeue, &from->dequeue); + blkg_stat_merge(&to->group_wait_time, &from->group_wait_time); + blkg_stat_merge(&to->idle_time, &from->idle_time); + blkg_stat_merge(&to->empty_time, &from->empty_time); +} + +/* + * Transfer @bfqg's stats to its parent's dead_stats so that the ancestors' + * recursive stats can still account for the amount used by this bfqg after + * it's gone. */ -static void bfq_group_chain_link(struct bfq_data *bfqd, - struct cgroup_subsys_state *css, - struct bfq_group *leaf) +static void bfqg_stats_xfer_dead(struct bfq_group *bfqg) { - struct bfqio_cgroup *bgrp; - struct bfq_group *bfqg, *next, *prev = NULL; - unsigned long flags; + struct bfq_group *parent; - assert_spin_locked(bfqd->queue->queue_lock); + if (!bfqg) /* root_group */ + return; - for (; css != NULL && leaf != NULL; css = css->parent) { - bgrp = css_to_bfqio(css); - next = leaf->bfqd; + parent = bfqg_parent(bfqg); - bfqg = bfqio_lookup_group(bgrp, bfqd); - BUG_ON(bfqg != NULL); + lockdep_assert_held(bfqg_to_blkg(bfqg)->q->queue_lock); - spin_lock_irqsave(&bgrp->lock, flags); + if (unlikely(!parent)) + return; - rcu_assign_pointer(leaf->bfqd, bfqd); - hlist_add_head_rcu(&leaf->group_node, &bgrp->group_data); - hlist_add_head(&leaf->bfqd_node, &bfqd->group_list); + bfqg_stats_merge(&parent->dead_stats, &bfqg->stats); + bfqg_stats_merge(&parent->dead_stats, &bfqg->dead_stats); + bfqg_stats_reset(&bfqg->stats); + bfqg_stats_reset(&bfqg->dead_stats); +} - spin_unlock_irqrestore(&bgrp->lock, flags); +static void bfq_init_entity(struct bfq_entity *entity, + struct bfq_group *bfqg) +{ + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); - prev = leaf; - leaf = next; + entity->weight = entity->new_weight; + entity->orig_weight = entity->new_weight; + if (bfqq) { + bfqq->ioprio = bfqq->new_ioprio; + bfqq->ioprio_class = bfqq->new_ioprio_class; + bfqg_get(bfqg); } + entity->parent = bfqg->my_entity; + entity->sched_data = &bfqg->sched_data; +} - BUG_ON(css == NULL && leaf != NULL); - if (css != NULL && prev != NULL) { - bgrp = css_to_bfqio(css); - bfqg = bfqio_lookup_group(bgrp, bfqd); - bfq_group_set_parent(prev, bfqg); - } +static void bfqg_stats_init(struct bfqg_stats *stats) +{ + blkg_rwstat_init(&stats->service_bytes); + blkg_rwstat_init(&stats->serviced); + blkg_rwstat_init(&stats->merged); + blkg_rwstat_init(&stats->service_time); + blkg_rwstat_init(&stats->wait_time); + blkg_rwstat_init(&stats->queued); + + blkg_stat_init(&stats->sectors); + blkg_stat_init(&stats->time); + + blkg_stat_init(&stats->unaccounted_time); + blkg_stat_init(&stats->avg_queue_size_sum); + blkg_stat_init(&stats->avg_queue_size_samples); + blkg_stat_init(&stats->dequeue); + blkg_stat_init(&stats->group_wait_time); + blkg_stat_init(&stats->idle_time); + blkg_stat_init(&stats->empty_time); +} + +static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd) + { + return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL; + } + +static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg) +{ + return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq)); +} + +static void bfq_cpd_init(const struct blkcg *blkcg) +{ + struct bfq_group_data *d = + cpd_to_bfqgd(blkcg->pd[blkcg_policy_bfq.plid]); + + d->weight = BFQ_DEFAULT_GRP_WEIGHT; +} + +static void bfq_pd_init(struct blkcg_gq *blkg) +{ + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + struct bfq_data *bfqd = blkg->q->elevator->elevator_data; + struct bfq_entity *entity = &bfqg->entity; + struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg); + + entity->orig_weight = entity->weight = entity->new_weight = d->weight; + entity->my_sched_data = &bfqg->sched_data; + bfqg->my_entity = entity; /* + * the root_group's will be set to NULL + * in bfq_init_queue() + */ + bfqg->bfqd = bfqd; + bfqg->active_entities = 0; + bfqg->rq_pos_tree = RB_ROOT; + + /* if the root_group does not exist, we are handling it right now */ + if (bfqd->root_group && bfqg != bfqd->root_group) + hlist_add_head(&bfqg->bfqd_node, &bfqd->group_list); + + bfqg_stats_init(&bfqg->stats); + bfqg_stats_init(&bfqg->dead_stats); +} + +/* offset delta from bfqg->stats to bfqg->dead_stats */ +static const int dead_stats_off_delta = offsetof(struct bfq_group, dead_stats) - + offsetof(struct bfq_group, stats); + +/* to be used by recursive prfill, sums live and dead stats recursively */ +static u64 bfqg_stat_pd_recursive_sum(struct blkg_policy_data *pd, int off) +{ + u64 sum = 0; + + sum += blkg_stat_recursive_sum(pd, off); + sum += blkg_stat_recursive_sum(pd, off + dead_stats_off_delta); + return sum; +} + +/* to be used by recursive prfill, sums live and dead rwstats recursively */ +static struct blkg_rwstat bfqg_rwstat_pd_recursive_sum(struct blkg_policy_data *pd, + int off) +{ + struct blkg_rwstat a, b; + + a = blkg_rwstat_recursive_sum(pd, off); + b = blkg_rwstat_recursive_sum(pd, off + dead_stats_off_delta); + blkg_rwstat_merge(&a, &b); + return a; +} + +static void bfq_pd_reset_stats(struct blkcg_gq *blkg) +{ + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + + bfqg_stats_reset(&bfqg->stats); + bfqg_stats_reset(&bfqg->dead_stats); +} + +static void bfq_group_set_parent(struct bfq_group *bfqg, + struct bfq_group *parent) +{ + struct bfq_entity *entity; + + BUG_ON(!parent); + BUG_ON(!bfqg); + BUG_ON(bfqg == parent); + + entity = &bfqg->entity; + entity->parent = parent->my_entity; + entity->sched_data = &parent->sched_data; } -/** - * bfq_find_alloc_group - return the group associated to @bfqd in @cgroup. - * @bfqd: queue descriptor. - * @cgroup: cgroup being searched for. - * - * Return a group associated to @bfqd in @cgroup, allocating one if - * necessary. When a group is returned all the cgroups in the path - * to the root have a group associated to @bfqd. - * - * If the allocation fails, return the root group: this breaks guarantees - * but is a safe fallback. If this loss becomes a problem it can be - * mitigated using the equivalent weight (given by the product of the - * weights of the groups in the path from @group to the root) in the - * root scheduler. - * - * We allocate all the missing nodes in the path from the leaf cgroup - * to the root and we connect the nodes only after all the allocations - * have been successful. - */ static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, - struct cgroup_subsys_state *css) + struct blkcg *blkcg) { - struct bfqio_cgroup *bgrp = css_to_bfqio(css); - struct bfq_group *bfqg; + struct request_queue *q = bfqd->queue; + struct bfq_group *bfqg = NULL, *parent; + struct bfq_entity *entity = NULL; - bfqg = bfqio_lookup_group(bgrp, bfqd); - if (bfqg != NULL) - return bfqg; + assert_spin_locked(bfqd->queue->queue_lock); - bfqg = bfq_group_chain_alloc(bfqd, css); - if (bfqg != NULL) - bfq_group_chain_link(bfqd, css, bfqg); - else + /* avoid lookup for the common case where there's no blkcg */ + if (blkcg == &blkcg_root) { bfqg = bfqd->root_group; + } else { + struct blkcg_gq *blkg; + + blkg = blkg_lookup_create(blkcg, q); + if (!IS_ERR(blkg)) + bfqg = blkg_to_bfqg(blkg); + else /* fallback to root_group */ + bfqg = bfqd->root_group; + } + + BUG_ON(!bfqg); + + /* + * Update chain of bfq_groups as we might be handling a leaf group + * which, along with some of its relatives, has not been hooked yet + * to the private hierarchy of BFQ. + */ + entity = &bfqg->entity; + for_each_entity(entity) { + bfqg = container_of(entity, struct bfq_group, entity); + BUG_ON(!bfqg); + if (bfqg != bfqd->root_group) { + parent = bfqg_parent(bfqg); + if (!parent) + parent = bfqd->root_group; + BUG_ON(!parent); + bfq_group_set_parent(bfqg, parent); + } + } return bfqg; } +static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq); + /** * bfq_bfqq_move - migrate @bfqq to @bfqg. * @bfqd: queue descriptor. @@ -296,6 +522,7 @@ static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, bfq_deactivate_bfqq(bfqd, bfqq, 0); } else if (entity->on_st) bfq_put_idle_entity(bfq_entity_service_tree(entity), entity); + bfqg_put(bfqq_group(bfqq)); /* * Here we use a reference to bfqg. We don't need a refcounter @@ -304,11 +531,15 @@ static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, */ entity->parent = bfqg->my_entity; entity->sched_data = &bfqg->sched_data; + bfqg_get(bfqg); - if (busy && resume) - bfq_activate_bfqq(bfqd, bfqq); + if (busy) { + bfq_pos_tree_add_move(bfqd, bfqq); + if (resume) + bfq_activate_bfqq(bfqd, bfqq); + } - if (bfqd->in_service_queue == NULL && !bfqd->rq_in_driver) + if (!bfqd->in_service_queue && !bfqd->rq_in_driver) bfq_schedule_dispatch(bfqd); } @@ -316,9 +547,9 @@ static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, * __bfq_bic_change_cgroup - move @bic to @cgroup. * @bfqd: the queue descriptor. * @bic: the bic to move. - * @cgroup: the cgroup to move to. + * @blkcg: the blk-cgroup to move to. * - * Move bic to cgroup, assuming that bfqd->queue is locked; the caller + * Move bic to blkcg, assuming that bfqd->queue is locked; the caller * has to make sure that the reference to cgroup is valid across the call. * * NOTE: an alternative approach might have been to store the current @@ -327,18 +558,17 @@ static void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq, */ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, struct bfq_io_cq *bic, - struct cgroup_subsys_state *css) + struct blkcg *blkcg) { struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0); struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1); - struct bfq_entity *entity; struct bfq_group *bfqg; - struct bfqio_cgroup *bgrp; + struct bfq_entity *entity; - bgrp = css_to_bfqio(css); + lockdep_assert_held(bfqd->queue->queue_lock); - bfqg = bfq_find_alloc_group(bfqd, css); - if (async_bfqq != NULL) { + bfqg = bfq_find_alloc_group(bfqd, blkcg); + if (async_bfqq) { entity = &async_bfqq->entity; if (entity->sched_data != &bfqg->sched_data) { @@ -350,7 +580,7 @@ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, } } - if (sync_bfqq != NULL) { + if (sync_bfqq) { entity = &sync_bfqq->entity; if (entity->sched_data != &bfqg->sched_data) bfq_bfqq_move(bfqd, sync_bfqq, entity, bfqg); @@ -359,74 +589,39 @@ static struct bfq_group *__bfq_bic_change_cgroup(struct bfq_data *bfqd, return bfqg; } -/** - * bfq_bic_change_cgroup - move @bic to @cgroup. - * @bic: the bic being migrated. - * @cgroup: the destination cgroup. - * - * When the task owning @bic is moved to @cgroup, @bic is immediately - * moved into its new parent group. - */ -static void bfq_bic_change_cgroup(struct bfq_io_cq *bic, - struct cgroup_subsys_state *css) -{ - struct bfq_data *bfqd; - unsigned long uninitialized_var(flags); - - bfqd = bfq_get_bfqd_locked(&(bic->icq.q->elevator->elevator_data), - &flags); - if (bfqd != NULL) { - __bfq_bic_change_cgroup(bfqd, bic, css); - bfq_put_bfqd_unlock(bfqd, &flags); - } -} - -/** - * bfq_bic_update_cgroup - update the cgroup of @bic. - * @bic: the @bic to update. - * - * Make sure that @bic is enqueued in the cgroup of the current task. - * We need this in addition to moving bics during the cgroup attach - * phase because the task owning @bic could be at its first disk - * access or we may end up in the root cgroup as the result of a - * memory allocation failure and here we try to move to the right - * group. - * - * Must be called under the queue lock. It is safe to use the returned - * value even after the rcu_read_unlock() as the migration/destruction - * paths act under the queue lock too. IOW it is impossible to race with - * group migration/destruction and end up with an invalid group as: - * a) here cgroup has not yet been destroyed, nor its destroy callback - * has started execution, as current holds a reference to it, - * b) if it is destroyed after rcu_read_unlock() [after current is - * migrated to a different cgroup] its attach() callback will have - * taken care of remove all the references to the old cgroup data. - */ -static struct bfq_group *bfq_bic_update_cgroup(struct bfq_io_cq *bic) +static void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) { struct bfq_data *bfqd = bic_to_bfqd(bic); - struct bfq_group *bfqg; - struct cgroup_subsys_state *css; - - BUG_ON(bfqd == NULL); + struct blkcg *blkcg; + struct bfq_group *bfqg = NULL; + uint64_t id; rcu_read_lock(); - css = task_css(current, bfqio_cgrp_id); - bfqg = __bfq_bic_change_cgroup(bfqd, bic, css); + blkcg = bio_blkcg(bio); + id = blkcg->css.serial_nr; rcu_read_unlock(); - return bfqg; + /* + * Check whether blkcg has changed. The condition may trigger + * spuriously on a newly created cic but there's no harm. + */ + if (unlikely(!bfqd) || likely(bic->blkcg_id == id)) + return; + + bfqg = __bfq_bic_change_cgroup(bfqd, bic, blkcg); + BUG_ON(!bfqg); + bic->blkcg_id = id; } /** * bfq_flush_idle_tree - deactivate any entity on the idle tree of @st. * @st: the service tree being flushed. */ -static inline void bfq_flush_idle_tree(struct bfq_service_tree *st) +static void bfq_flush_idle_tree(struct bfq_service_tree *st) { struct bfq_entity *entity = st->first_idle; - for (; entity != NULL; entity = st->first_idle) + for (; entity ; entity = st->first_idle) __bfq_deactivate_entity(entity, 0); } @@ -435,12 +630,12 @@ static inline void bfq_flush_idle_tree(struct bfq_service_tree *st) * @bfqd: the device data structure with the root group. * @entity: the entity to move. */ -static inline void bfq_reparent_leaf_entity(struct bfq_data *bfqd, - struct bfq_entity *entity) +static void bfq_reparent_leaf_entity(struct bfq_data *bfqd, + struct bfq_entity *entity) { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); - BUG_ON(bfqq == NULL); + BUG_ON(!bfqq); bfq_bfqq_move(bfqd, bfqq, entity, bfqd->root_group); return; } @@ -454,9 +649,9 @@ static inline void bfq_reparent_leaf_entity(struct bfq_data *bfqd, * * Needs queue_lock to be taken and reference to be valid over the call. */ -static inline void bfq_reparent_active_entities(struct bfq_data *bfqd, - struct bfq_group *bfqg, - struct bfq_service_tree *st) +static void bfq_reparent_active_entities(struct bfq_data *bfqd, + struct bfq_group *bfqg, + struct bfq_service_tree *st) { struct rb_root *active = &st->active; struct bfq_entity *entity = NULL; @@ -464,10 +659,10 @@ static inline void bfq_reparent_active_entities(struct bfq_data *bfqd, if (!RB_EMPTY_ROOT(&st->active)) entity = bfq_entity_of(rb_first(active)); - for (; entity != NULL; entity = bfq_entity_of(rb_first(active))) + for (; entity ; entity = bfq_entity_of(rb_first(active))) bfq_reparent_leaf_entity(bfqd, entity); - if (bfqg->sched_data.in_service_entity != NULL) + if (bfqg->sched_data.in_service_entity) bfq_reparent_leaf_entity(bfqd, bfqg->sched_data.in_service_entity); @@ -476,20 +671,21 @@ static inline void bfq_reparent_active_entities(struct bfq_data *bfqd, /** * bfq_destroy_group - destroy @bfqg. - * @bgrp: the bfqio_cgroup containing @bfqg. * @bfqg: the group being destroyed. * * Destroy @bfqg, making sure that it is not referenced from its parent. + * blkio already grabs the queue_lock for us, so no need to use RCU-based magic */ -static void bfq_destroy_group(struct bfqio_cgroup *bgrp, struct bfq_group *bfqg) +static void bfq_pd_offline(struct blkcg_gq *blkg) { - struct bfq_data *bfqd; struct bfq_service_tree *st; + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + struct bfq_data *bfqd = bfqg->bfqd; struct bfq_entity *entity = bfqg->my_entity; - unsigned long uninitialized_var(flags); int i; - hlist_del(&bfqg->group_node); + if (!entity) /* root group */ + return; /* * Empty all service_trees belonging to this group before @@ -518,37 +714,19 @@ static void bfq_destroy_group(struct bfqio_cgroup *bgrp, struct bfq_group *bfqg) * There is no need to put the sync queues, as the * scheduler has taken no reference. */ - bfqd = bfq_get_bfqd_locked(&bfqg->bfqd, &flags); - if (bfqd != NULL) { - bfq_reparent_active_entities(bfqd, bfqg, st); - bfq_put_bfqd_unlock(bfqd, &flags); - } + bfq_reparent_active_entities(bfqd, bfqg, st); BUG_ON(!RB_EMPTY_ROOT(&st->active)); BUG_ON(!RB_EMPTY_ROOT(&st->idle)); } - BUG_ON(bfqg->sched_data.next_in_service != NULL); - BUG_ON(bfqg->sched_data.in_service_entity != NULL); + BUG_ON(bfqg->sched_data.next_in_service); + BUG_ON(bfqg->sched_data.in_service_entity); - /* - * We may race with device destruction, take extra care when - * dereferencing bfqg->bfqd. - */ - bfqd = bfq_get_bfqd_locked(&bfqg->bfqd, &flags); - if (bfqd != NULL) { - hlist_del(&bfqg->bfqd_node); - __bfq_deactivate_entity(entity, 0); - bfq_put_async_queues(bfqd, bfqg); - bfq_put_bfqd_unlock(bfqd, &flags); - } - BUG_ON(entity->tree != NULL); + hlist_del(&bfqg->bfqd_node); + __bfq_deactivate_entity(entity, 0); + bfq_put_async_queues(bfqd, bfqg); + BUG_ON(entity->tree); - /* - * No need to defer the kfree() to the end of the RCU grace - * period: we are called from the destroy() callback of our - * cgroup, so we can be sure that no one is a) still using - * this cgroup or b) doing lookups in it. - */ - kfree(bfqg); + bfqg_stats_xfer_dead(bfqg); } static void bfq_end_wr_async(struct bfq_data *bfqd) @@ -595,312 +773,309 @@ static void bfq_disconnect_groups(struct bfq_data *bfqd) } } -static inline void bfq_free_root_group(struct bfq_data *bfqd) +static u64 bfqio_cgroup_weight_read(struct cgroup_subsys_state *css, + struct cftype *cftype) { - struct bfqio_cgroup *bgrp = &bfqio_root_cgroup; - struct bfq_group *bfqg = bfqd->root_group; - - bfq_put_async_queues(bfqd, bfqg); + struct blkcg *blkcg = css_to_blkcg(css); + struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); + int ret = -EINVAL; - spin_lock_irq(&bgrp->lock); - hlist_del_rcu(&bfqg->group_node); - spin_unlock_irq(&bgrp->lock); + spin_lock_irq(&blkcg->lock); + ret = bfqgd->weight; + spin_unlock_irq(&blkcg->lock); - /* - * No need to synchronize_rcu() here: since the device is gone - * there cannot be any read-side access to its root_group. - */ - kfree(bfqg); + return ret; } -static struct bfq_group *bfq_alloc_root_group(struct bfq_data *bfqd, int node) +static int bfqio_cgroup_weight_write(struct cgroup_subsys_state *css, + struct cftype *cftype, + u64 val) { - struct bfq_group *bfqg; - struct bfqio_cgroup *bgrp; - int i; - - bfqg = kzalloc_node(sizeof(*bfqg), GFP_KERNEL, node); - if (bfqg == NULL) - return NULL; - - bfqg->entity.parent = NULL; - for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) - bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; - - bgrp = &bfqio_root_cgroup; - spin_lock_irq(&bgrp->lock); - rcu_assign_pointer(bfqg->bfqd, bfqd); - hlist_add_head_rcu(&bfqg->group_node, &bgrp->group_data); - spin_unlock_irq(&bgrp->lock); + struct blkcg *blkcg = css_to_blkcg(css); + struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg); + struct blkcg_gq *blkg; + int ret = -EINVAL; + + if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT) + return ret; + + ret = 0; + spin_lock_irq(&blkcg->lock); + bfqgd->weight = (unsigned short)val; + hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) { + struct bfq_group *bfqg = blkg_to_bfqg(blkg); + if (!bfqg) + continue; + /* + * Setting the prio_changed flag of the entity + * to 1 with new_weight == weight would re-set + * the value of the weight to its ioprio mapping. + * Set the flag only if necessary. + */ + if ((unsigned short)val != bfqg->entity.new_weight) { + bfqg->entity.new_weight = (unsigned short)val; + /* + * Make sure that the above new value has been + * stored in bfqg->entity.new_weight before + * setting the prio_changed flag. In fact, + * this flag may be read asynchronously (in + * critical sections protected by a different + * lock than that held here), and finding this + * flag set may cause the execution of the code + * for updating parameters whose value may + * depend also on bfqg->entity.new_weight (in + * __bfq_entity_update_weight_prio). + * This barrier makes sure that the new value + * of bfqg->entity.new_weight is correctly + * seen in that code. + */ + smp_wmb(); + bfqg->entity.prio_changed = 1; + } + } + spin_unlock_irq(&blkcg->lock); - return bfqg; + return ret; } -#define SHOW_FUNCTION(__VAR) \ -static u64 bfqio_cgroup_##__VAR##_read(struct cgroup_subsys_state *css, \ - struct cftype *cftype) \ -{ \ - struct bfqio_cgroup *bgrp = css_to_bfqio(css); \ - u64 ret = -ENODEV; \ - \ - mutex_lock(&bfqio_mutex); \ - if (bfqio_is_removed(bgrp)) \ - goto out_unlock; \ - \ - spin_lock_irq(&bgrp->lock); \ - ret = bgrp->__VAR; \ - spin_unlock_irq(&bgrp->lock); \ - \ -out_unlock: \ - mutex_unlock(&bfqio_mutex); \ - return ret; \ -} - -SHOW_FUNCTION(weight); -SHOW_FUNCTION(ioprio); -SHOW_FUNCTION(ioprio_class); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__VAR, __MIN, __MAX) \ -static int bfqio_cgroup_##__VAR##_write(struct cgroup_subsys_state *css,\ - struct cftype *cftype, \ - u64 val) \ -{ \ - struct bfqio_cgroup *bgrp = css_to_bfqio(css); \ - struct bfq_group *bfqg; \ - int ret = -EINVAL; \ - \ - if (val < (__MIN) || val > (__MAX)) \ - return ret; \ - \ - ret = -ENODEV; \ - mutex_lock(&bfqio_mutex); \ - if (bfqio_is_removed(bgrp)) \ - goto out_unlock; \ - ret = 0; \ - \ - spin_lock_irq(&bgrp->lock); \ - bgrp->__VAR = (unsigned short)val; \ - hlist_for_each_entry(bfqg, &bgrp->group_data, group_node) { \ - /* \ - * Setting the ioprio_changed flag of the entity \ - * to 1 with new_##__VAR == ##__VAR would re-set \ - * the value of the weight to its ioprio mapping. \ - * Set the flag only if necessary. \ - */ \ - if ((unsigned short)val != bfqg->entity.new_##__VAR) { \ - bfqg->entity.new_##__VAR = (unsigned short)val; \ - /* \ - * Make sure that the above new value has been \ - * stored in bfqg->entity.new_##__VAR before \ - * setting the ioprio_changed flag. In fact, \ - * this flag may be read asynchronously (in \ - * critical sections protected by a different \ - * lock than that held here), and finding this \ - * flag set may cause the execution of the code \ - * for updating parameters whose value may \ - * depend also on bfqg->entity.new_##__VAR (in \ - * __bfq_entity_update_weight_prio). \ - * This barrier makes sure that the new value \ - * of bfqg->entity.new_##__VAR is correctly \ - * seen in that code. \ - */ \ - smp_wmb(); \ - bfqg->entity.ioprio_changed = 1; \ - } \ - } \ - spin_unlock_irq(&bgrp->lock); \ - \ -out_unlock: \ - mutex_unlock(&bfqio_mutex); \ - return ret; \ -} - -STORE_FUNCTION(weight, BFQ_MIN_WEIGHT, BFQ_MAX_WEIGHT); -STORE_FUNCTION(ioprio, 0, IOPRIO_BE_NR - 1); -STORE_FUNCTION(ioprio_class, IOPRIO_CLASS_RT, IOPRIO_CLASS_IDLE); -#undef STORE_FUNCTION +static int bfqg_print_stat(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat, + &blkcg_policy_bfq, seq_cft(sf)->private, false); + return 0; +} -static struct cftype bfqio_files[] = { - { - .name = "weight", - .read_u64 = bfqio_cgroup_weight_read, - .write_u64 = bfqio_cgroup_weight_write, - }, - { - .name = "ioprio", - .read_u64 = bfqio_cgroup_ioprio_read, - .write_u64 = bfqio_cgroup_ioprio_write, - }, - { - .name = "ioprio_class", - .read_u64 = bfqio_cgroup_ioprio_class_read, - .write_u64 = bfqio_cgroup_ioprio_class_write, - }, - { }, /* terminate */ -}; +static int bfqg_print_rwstat(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat, + &blkcg_policy_bfq, seq_cft(sf)->private, true); + return 0; +} -static struct cgroup_subsys_state *bfqio_create(struct cgroup_subsys_state - *parent_css) +static u64 bfqg_prfill_stat_recursive(struct seq_file *sf, + struct blkg_policy_data *pd, int off) { - struct bfqio_cgroup *bgrp; + u64 sum = bfqg_stat_pd_recursive_sum(pd, off); - if (parent_css != NULL) { - bgrp = kzalloc(sizeof(*bgrp), GFP_KERNEL); - if (bgrp == NULL) - return ERR_PTR(-ENOMEM); - } else - bgrp = &bfqio_root_cgroup; + return __blkg_prfill_u64(sf, pd, sum); +} - spin_lock_init(&bgrp->lock); - INIT_HLIST_HEAD(&bgrp->group_data); - bgrp->ioprio = BFQ_DEFAULT_GRP_IOPRIO; - bgrp->ioprio_class = BFQ_DEFAULT_GRP_CLASS; +static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf, + struct blkg_policy_data *pd, int off) +{ + struct blkg_rwstat sum = bfqg_rwstat_pd_recursive_sum(pd, off); - return &bgrp->css; + return __blkg_prfill_rwstat(sf, pd, &sum); } -/* - * We cannot support shared io contexts, as we have no means to support - * two tasks with the same ioc in two different groups without major rework - * of the main bic/bfqq data structures. By now we allow a task to change - * its cgroup only if it's the only owner of its ioc; the drawback of this - * behavior is that a group containing a task that forked using CLONE_IO - * will not be destroyed until the tasks sharing the ioc die. - */ -static int bfqio_can_attach(struct cgroup_subsys_state *css, - struct cgroup_taskset *tset) +static int bfqg_print_stat_recursive(struct seq_file *sf, void *v) { - struct task_struct *task; - struct io_context *ioc; - int ret = 0; - - cgroup_taskset_for_each(task, tset) { - /* - * task_lock() is needed to avoid races with - * exit_io_context() - */ - task_lock(task); - ioc = task->io_context; - if (ioc != NULL && atomic_read(&ioc->nr_tasks) > 1) - /* - * ioc == NULL means that the task is either too - * young or exiting: if it has still no ioc the - * ioc can't be shared, if the task is exiting the - * attach will fail anyway, no matter what we - * return here. - */ - ret = -EINVAL; - task_unlock(task); - if (ret) - break; - } + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_stat_recursive, &blkcg_policy_bfq, + seq_cft(sf)->private, false); + return 0; +} - return ret; +static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v) +{ + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq, + seq_cft(sf)->private, true); + return 0; } -static void bfqio_attach(struct cgroup_subsys_state *css, - struct cgroup_taskset *tset) +static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf, + struct blkg_policy_data *pd, int off) { - struct task_struct *task; - struct io_context *ioc; - struct io_cq *icq; + struct bfq_group *bfqg = pd_to_bfqg(pd); + u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples); + u64 v = 0; - /* - * IMPORTANT NOTE: The move of more than one process at a time to a - * new group has not yet been tested. - */ - cgroup_taskset_for_each(task, tset) { - ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE); - if (ioc) { - /* - * Handle cgroup change here. - */ - rcu_read_lock(); - hlist_for_each_entry_rcu(icq, &ioc->icq_list, ioc_node) - if (!strncmp( - icq->q->elevator->type->elevator_name, - "bfq", ELV_NAME_MAX)) - bfq_bic_change_cgroup(icq_to_bic(icq), - css); - rcu_read_unlock(); - put_io_context(ioc); - } + if (samples) { + v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum); + v = div64_u64(v, samples); } + __blkg_prfill_u64(sf, pd, v); + return 0; } -static void bfqio_destroy(struct cgroup_subsys_state *css) +/* print avg_queue_size */ +static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v) { - struct bfqio_cgroup *bgrp = css_to_bfqio(css); - struct hlist_node *tmp; - struct bfq_group *bfqg; - - /* - * Since we are destroying the cgroup, there are no more tasks - * referencing it, and all the RCU grace periods that may have - * referenced it are ended (as the destruction of the parent - * cgroup is RCU-safe); bgrp->group_data will not be accessed by - * anything else and we don't need any synchronization. - */ - hlist_for_each_entry_safe(bfqg, tmp, &bgrp->group_data, group_node) - bfq_destroy_group(bgrp, bfqg); - - BUG_ON(!hlist_empty(&bgrp->group_data)); - - kfree(bgrp); + blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), + bfqg_prfill_avg_queue_size, &blkcg_policy_bfq, + 0, false); + return 0; } -static int bfqio_css_online(struct cgroup_subsys_state *css) +static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) { - struct bfqio_cgroup *bgrp = css_to_bfqio(css); + int ret; - mutex_lock(&bfqio_mutex); - bgrp->online = true; - mutex_unlock(&bfqio_mutex); + ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq); + if (ret) + return NULL; - return 0; + return blkg_to_bfqg(bfqd->queue->root_blkg); } -static void bfqio_css_offline(struct cgroup_subsys_state *css) -{ - struct bfqio_cgroup *bgrp = css_to_bfqio(css); +static struct cftype bfqio_files[] = { + { + .name = "bfq.weight", + .read_u64 = bfqio_cgroup_weight_read, + .write_u64 = bfqio_cgroup_weight_write, + }, + /* statistics, cover only the tasks in the bfqg */ + { + .name = "bfq.time", + .private = offsetof(struct bfq_group, stats.time), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.sectors", + .private = offsetof(struct bfq_group, stats.sectors), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.io_service_bytes", + .private = offsetof(struct bfq_group, stats.service_bytes), + .seq_show = bfqg_print_rwstat, + }, + { + .name = "bfq.io_serviced", + .private = offsetof(struct bfq_group, stats.serviced), + .seq_show = bfqg_print_rwstat, + }, + { + .name = "bfq.io_service_time", + .private = offsetof(struct bfq_group, stats.service_time), + .seq_show = bfqg_print_rwstat, + }, + { + .name = "bfq.io_wait_time", + .private = offsetof(struct bfq_group, stats.wait_time), + .seq_show = bfqg_print_rwstat, + }, + { + .name = "bfq.io_merged", + .private = offsetof(struct bfq_group, stats.merged), + .seq_show = bfqg_print_rwstat, + }, + { + .name = "bfq.io_queued", + .private = offsetof(struct bfq_group, stats.queued), + .seq_show = bfqg_print_rwstat, + }, - mutex_lock(&bfqio_mutex); - bgrp->online = false; - mutex_unlock(&bfqio_mutex); -} + /* the same statictics which cover the bfqg and its descendants */ + { + .name = "bfq.time_recursive", + .private = offsetof(struct bfq_group, stats.time), + .seq_show = bfqg_print_stat_recursive, + }, + { + .name = "bfq.sectors_recursive", + .private = offsetof(struct bfq_group, stats.sectors), + .seq_show = bfqg_print_stat_recursive, + }, + { + .name = "bfq.io_service_bytes_recursive", + .private = offsetof(struct bfq_group, stats.service_bytes), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.io_serviced_recursive", + .private = offsetof(struct bfq_group, stats.serviced), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.io_service_time_recursive", + .private = offsetof(struct bfq_group, stats.service_time), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.io_wait_time_recursive", + .private = offsetof(struct bfq_group, stats.wait_time), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.io_merged_recursive", + .private = offsetof(struct bfq_group, stats.merged), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.io_queued_recursive", + .private = offsetof(struct bfq_group, stats.queued), + .seq_show = bfqg_print_rwstat_recursive, + }, + { + .name = "bfq.avg_queue_size", + .seq_show = bfqg_print_avg_queue_size, + }, + { + .name = "bfq.group_wait_time", + .private = offsetof(struct bfq_group, stats.group_wait_time), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.idle_time", + .private = offsetof(struct bfq_group, stats.idle_time), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.empty_time", + .private = offsetof(struct bfq_group, stats.empty_time), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.dequeue", + .private = offsetof(struct bfq_group, stats.dequeue), + .seq_show = bfqg_print_stat, + }, + { + .name = "bfq.unaccounted_time", + .private = offsetof(struct bfq_group, stats.unaccounted_time), + .seq_show = bfqg_print_stat, + }, + { } /* terminate */ +}; -struct cgroup_subsys bfqio_cgrp_subsys = { - .css_alloc = bfqio_create, - .css_online = bfqio_css_online, - .css_offline = bfqio_css_offline, - .can_attach = bfqio_can_attach, - .attach = bfqio_attach, - .css_free = bfqio_destroy, - .legacy_cftypes = bfqio_files, +static struct blkcg_policy blkcg_policy_bfq = { + .pd_size = sizeof(struct bfq_group), + .cpd_size = sizeof(struct bfq_group_data), + .cftypes = bfqio_files, + .pd_init_fn = bfq_pd_init, + .cpd_init_fn = bfq_cpd_init, + .pd_offline_fn = bfq_pd_offline, + .pd_reset_stats_fn = bfq_pd_reset_stats, }; + #else -static inline void bfq_init_entity(struct bfq_entity *entity, - struct bfq_group *bfqg) + +static void bfq_init_entity(struct bfq_entity *entity, + struct bfq_group *bfqg) { + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); entity->weight = entity->new_weight; entity->orig_weight = entity->new_weight; - entity->ioprio = entity->new_ioprio; - entity->ioprio_class = entity->new_ioprio_class; + if (bfqq) { + bfqq->ioprio = bfqq->new_ioprio; + bfqq->ioprio_class = bfqq->new_ioprio_class; + } entity->sched_data = &bfqg->sched_data; } -static inline struct bfq_group * -bfq_bic_update_cgroup(struct bfq_io_cq *bic) +static struct bfq_group * +bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) { struct bfq_data *bfqd = bic_to_bfqd(bic); return bfqd->root_group; } -static inline void bfq_bfqq_move(struct bfq_data *bfqd, - struct bfq_queue *bfqq, - struct bfq_entity *entity, - struct bfq_group *bfqg) +static void bfq_bfqq_move(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + struct bfq_entity *entity, + struct bfq_group *bfqg) { } @@ -909,23 +1084,24 @@ static void bfq_end_wr_async(struct bfq_data *bfqd) bfq_end_wr_async_queues(bfqd, bfqd->root_group); } -static inline void bfq_disconnect_groups(struct bfq_data *bfqd) +static void bfq_disconnect_groups(struct bfq_data *bfqd) { bfq_put_async_queues(bfqd, bfqd->root_group); } -static inline void bfq_free_root_group(struct bfq_data *bfqd) +static struct bfq_group *bfq_find_alloc_group(struct bfq_data *bfqd, + struct blkcg *blkcg) { - kfree(bfqd->root_group); + return bfqd->root_group; } -static struct bfq_group *bfq_alloc_root_group(struct bfq_data *bfqd, int node) +static struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node) { struct bfq_group *bfqg; int i; bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node); - if (bfqg == NULL) + if (!bfqg) return NULL; for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) diff --git a/block/bfq-ioc.c b/block/bfq-ioc.c index 7f6b0004c..fb7bb8f08 100644 --- a/block/bfq-ioc.c +++ b/block/bfq-ioc.c @@ -14,7 +14,7 @@ * icq_to_bic - convert iocontext queue structure to bfq_io_cq. * @icq: the iocontext queue. */ -static inline struct bfq_io_cq *icq_to_bic(struct io_cq *icq) +static struct bfq_io_cq *icq_to_bic(struct io_cq *icq) { /* bic->icq is the first member, %NULL will convert to %NULL */ return container_of(icq, struct bfq_io_cq, icq); @@ -27,8 +27,8 @@ static inline struct bfq_io_cq *icq_to_bic(struct io_cq *icq) * * Queue lock must be held. */ -static inline struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, - struct io_context *ioc) +static struct bfq_io_cq *bfq_bic_lookup(struct bfq_data *bfqd, + struct io_context *ioc) { if (ioc) return icq_to_bic(ioc_lookup_icq(ioc, bfqd->queue)); diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 71b51c1b4..05944cbaa 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -82,6 +82,9 @@ static const int bfq_back_penalty = 2; /* Idling period duration, in jiffies. */ static int bfq_slice_idle = HZ / 125; +/* Minimum number of assigned budgets for which stats are safe to compute. */ +static const int bfq_stats_min_budgets = 194; + /* Default maximum budget values, in sectors and number of requests. */ static const int bfq_default_max_budget = 16 * 1024; static const int bfq_max_budget_async_rq = 4; @@ -163,38 +166,22 @@ static int device_speed_thresh[2]; #define RQ_BIC(rq) ((struct bfq_io_cq *) (rq)->elv.priv[0]) #define RQ_BFQQ(rq) ((rq)->elv.priv[1]) -static inline void bfq_schedule_dispatch(struct bfq_data *bfqd); +static void bfq_schedule_dispatch(struct bfq_data *bfqd); #include "bfq-ioc.c" #include "bfq-sched.c" #include "bfq-cgroup.c" -#define bfq_class_idle(bfqq) ((bfqq)->entity.ioprio_class ==\ - IOPRIO_CLASS_IDLE) -#define bfq_class_rt(bfqq) ((bfqq)->entity.ioprio_class ==\ - IOPRIO_CLASS_RT) +#define bfq_class_idle(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_IDLE) +#define bfq_class_rt(bfqq) ((bfqq)->ioprio_class == IOPRIO_CLASS_RT) #define bfq_sample_valid(samples) ((samples) > 80) /* - * The following macro groups conditions that need to be evaluated when - * checking if existing queues and groups form a symmetric scenario - * and therefore idling can be reduced or disabled for some of the - * queues. See the comment to the function bfq_bfqq_must_not_expire() - * for further details. - */ -#ifdef CONFIG_CGROUP_BFQIO -#define symmetric_scenario (!bfqd->active_numerous_groups && \ - !bfq_differentiated_weights(bfqd)) -#else -#define symmetric_scenario (!bfq_differentiated_weights(bfqd)) -#endif - -/* * We regard a request as SYNC, if either it's a read or has the SYNC bit * set (in which case it could also be a direct WRITE). */ -static inline int bfq_bio_sync(struct bio *bio) +static int bfq_bio_sync(struct bio *bio) { if (bio_data_dir(bio) == READ || (bio->bi_rw & REQ_SYNC)) return 1; @@ -206,7 +193,7 @@ static inline int bfq_bio_sync(struct bio *bio) * Scheduler run of queue, if there are requests pending and no one in the * driver that will restart queueing. */ -static inline void bfq_schedule_dispatch(struct bfq_data *bfqd) +static void bfq_schedule_dispatch(struct bfq_data *bfqd) { if (bfqd->queued != 0) { bfq_log(bfqd, "schedule dispatch"); @@ -230,9 +217,9 @@ static struct request *bfq_choose_req(struct bfq_data *bfqd, #define BFQ_RQ2_WRAP 0x02 /* request 2 wraps */ unsigned wrap = 0; /* bit mask: requests behind the disk head? */ - if (rq1 == NULL || rq1 == rq2) + if (!rq1 || rq1 == rq2) return rq2; - if (rq2 == NULL) + if (!rq2) return rq1; if (rq_is_sync(rq1) && !rq_is_sync(rq2)) @@ -345,17 +332,17 @@ bfq_rq_pos_tree_lookup(struct bfq_data *bfqd, struct rb_root *root, bfq_log(bfqd, "rq_pos_tree_lookup %llu: returning %d", (long long unsigned)sector, - bfqq != NULL ? bfqq->pid : 0); + bfqq ? bfqq->pid : 0); return bfqq; } -static void bfq_rq_pos_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq) +static void bfq_pos_tree_add_move(struct bfq_data *bfqd, struct bfq_queue *bfqq) { struct rb_node **p, *parent; struct bfq_queue *__bfqq; - if (bfqq->pos_root != NULL) { + if (bfqq->pos_root) { rb_erase(&bfqq->pos_node, bfqq->pos_root); bfqq->pos_root = NULL; } @@ -365,10 +352,10 @@ static void bfq_rq_pos_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq) if (!bfqq->next_rq) return; - bfqq->pos_root = &bfqd->rq_pos_tree; + bfqq->pos_root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; __bfqq = bfq_rq_pos_tree_lookup(bfqd, bfqq->pos_root, blk_rq_pos(bfqq->next_rq), &parent, &p); - if (__bfqq == NULL) { + if (!__bfqq) { rb_link_node(&bfqq->pos_node, parent, p); rb_insert_color(&bfqq->pos_node, bfqq->pos_root); } else @@ -378,7 +365,7 @@ static void bfq_rq_pos_tree_add(struct bfq_data *bfqd, struct bfq_queue *bfqq) /* * Tell whether there are active queues or groups with differentiated weights. */ -static inline bool bfq_differentiated_weights(struct bfq_data *bfqd) +static bool bfq_differentiated_weights(struct bfq_data *bfqd) { /* * For weights to differ, at least one of the trees must contain @@ -387,7 +374,7 @@ static inline bool bfq_differentiated_weights(struct bfq_data *bfqd) return (!RB_EMPTY_ROOT(&bfqd->queue_weights_tree) && (bfqd->queue_weights_tree.rb_node->rb_left || bfqd->queue_weights_tree.rb_node->rb_right) -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED ) || (!RB_EMPTY_ROOT(&bfqd->group_weights_tree) && (bfqd->group_weights_tree.rb_node->rb_left || @@ -397,6 +384,40 @@ static inline bool bfq_differentiated_weights(struct bfq_data *bfqd) } /* + * The following function returns true if every queue must receive the + * same share of the throughput (this condition is used when deciding + * whether idling may be disabled, see the comments in the function + * bfq_bfqq_may_idle()). + * + * Such a scenario occurs when: + * 1) all active queues have the same weight, + * 2) all active groups at the same level in the groups tree have the same + * weight, + * 3) all active groups at the same level in the groups tree have the same + * number of children. + * + * Unfortunately, keeping the necessary state for evaluating exactly the + * above symmetry conditions would be quite complex and time-consuming. + * Therefore this function evaluates, instead, the following stronger + * sub-conditions, for which it is much easier to maintain the needed + * state: + * 1) all active queues have the same weight, + * 2) all active groups have the same weight, + * 3) all active groups have at most one active child each. + * In particular, the last two conditions are always true if hierarchical + * support and the cgroups interface are not enabled, thus no state needs + * to be maintained in this case. + */ +static bool bfq_symmetric_scenario(struct bfq_data *bfqd) +{ + return +#ifdef CONFIG_BFQ_GROUP_IOSCHED + !bfqd->active_numerous_groups && +#endif + !bfq_differentiated_weights(bfqd); +} + +/* * If the weight-counter tree passed as input contains no counter for * the weight of the input entity, then add that counter; otherwise just * increment the existing counter. @@ -495,10 +516,10 @@ static struct request *bfq_find_next_rq(struct bfq_data *bfqd, BUG_ON(RB_EMPTY_NODE(&last->rb_node)); - if (rbprev != NULL) + if (rbprev) prev = rb_entry_rq(rbprev); - if (rbnext != NULL) + if (rbnext) next = rb_entry_rq(rbnext); else { rbnext = rb_first(&bfqq->sort_list); @@ -510,8 +531,8 @@ static struct request *bfq_find_next_rq(struct bfq_data *bfqd, } /* see the definition of bfq_async_charge_factor for details */ -static inline unsigned long bfq_serv_to_charge(struct request *rq, - struct bfq_queue *bfqq) +static unsigned long bfq_serv_to_charge(struct request *rq, + struct bfq_queue *bfqq) { return blk_rq_sectors(rq) * (1 + ((!bfq_bfqq_sync(bfqq)) * (bfqq->wr_coeff == 1) * @@ -537,7 +558,7 @@ static void bfq_updated_next_req(struct bfq_data *bfqd, struct request *next_rq = bfqq->next_rq; unsigned long new_budget; - if (next_rq == NULL) + if (!next_rq) return; if (bfqq == bfqd->in_service_queue) @@ -560,7 +581,7 @@ static void bfq_updated_next_req(struct bfq_data *bfqd, } } -static inline unsigned int bfq_wr_duration(struct bfq_data *bfqd) +static unsigned int bfq_wr_duration(struct bfq_data *bfqd) { u64 dur; @@ -573,13 +594,12 @@ static inline unsigned int bfq_wr_duration(struct bfq_data *bfqd) return dur; } -static inline unsigned -bfq_bfqq_cooperations(struct bfq_queue *bfqq) +static unsigned bfq_bfqq_cooperations(struct bfq_queue *bfqq) { return bfqq->bic ? bfqq->bic->cooperations : 0; } -static inline void +static void bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic) { if (bic->saved_idle_window) @@ -603,7 +623,7 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic) bfqq->wr_coeff = bfqq->bfqd->bfq_wr_coeff; bfqq->wr_cur_max_time = bic->wr_time_left; bfqq->last_wr_start_finish = jiffies; - bfqq->entity.ioprio_changed = 1; + bfqq->entity.prio_changed = 1; } /* * Clear wr_time_left to prevent bfq_bfqq_save_state() from @@ -613,11 +633,12 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_io_cq *bic) bic->wr_time_left = 0; } -/* Must be called with the queue_lock held. */ static int bfqq_process_refs(struct bfq_queue *bfqq) { int process_refs, io_refs; + lockdep_assert_held(bfqq->bfqd->queue->queue_lock); + io_refs = bfqq->allocated[READ] + bfqq->allocated[WRITE]; process_refs = atomic_read(&bfqq->ref) - io_refs - bfqq->entity.on_st; BUG_ON(process_refs < 0); @@ -625,8 +646,7 @@ static int bfqq_process_refs(struct bfq_queue *bfqq) } /* Empty burst list and add just bfqq (see comments to bfq_handle_burst) */ -static inline void bfq_reset_burst_list(struct bfq_data *bfqd, - struct bfq_queue *bfqq) +static void bfq_reset_burst_list(struct bfq_data *bfqd, struct bfq_queue *bfqq) { struct bfq_queue *item; struct hlist_node *n; @@ -858,14 +878,14 @@ static void bfq_add_request(struct request *rq) */ prev = bfqq->next_rq; next_rq = bfq_choose_req(bfqd, bfqq->next_rq, rq, bfqd->last_position); - BUG_ON(next_rq == NULL); + BUG_ON(!next_rq); bfqq->next_rq = next_rq; /* * Adjust priority tree position, if next_rq changes. */ if (prev != bfqq->next_rq) - bfq_rq_pos_tree_add(bfqd, bfqq); + bfq_pos_tree_add_move(bfqd, bfqq); if (!bfq_bfqq_busy(bfqq)) { bool soft_rt, coop_or_in_burst, @@ -873,6 +893,10 @@ static void bfq_add_request(struct request *rq) bfqq->budget_timeout + bfqd->bfq_wr_min_idle_time); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_io_add(bfqq_group(RQ_BFQQ(rq)), bfqq, + rq->cmd_flags); +#endif if (bfq_bfqq_sync(bfqq)) { bool already_in_burst = !hlist_unhashed(&bfqq->burst_list_node) || @@ -917,7 +941,7 @@ static void bfq_add_request(struct request *rq) goto add_bfqq_busy; if (bfq_bfqq_just_split(bfqq)) - goto set_ioprio_changed; + goto set_prio_changed; /* * If the queue: @@ -929,7 +953,7 @@ static void bfq_add_request(struct request *rq) * start a weight-raising period. */ if (old_wr_coeff == 1 && (interactive || soft_rt) && - (!bfq_bfqq_sync(bfqq) || bfqq->bic != NULL)) { + (!bfq_bfqq_sync(bfqq) || bfqq->bic)) { bfqq->wr_coeff = bfqd->bfq_wr_coeff; if (interactive) bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); @@ -1008,9 +1032,9 @@ static void bfq_add_request(struct request *rq) bfqd->bfq_wr_rt_max_time; } } -set_ioprio_changed: +set_prio_changed: if (old_wr_coeff != bfqq->wr_coeff) - entity->ioprio_changed = 1; + entity->prio_changed = 1; add_bfqq_busy: bfqq->last_idle_bklogged = jiffies; bfqq->service_from_backlogged = 0; @@ -1025,7 +1049,7 @@ add_bfqq_busy: bfqq->wr_cur_max_time = bfq_wr_duration(bfqd); bfqd->wr_busy_queues++; - entity->ioprio_changed = 1; + entity->prio_changed = 1; bfq_log_bfqq(bfqd, bfqq, "non-idle wrais starting at %lu, rais_max_time %u", jiffies, @@ -1048,11 +1072,11 @@ static struct request *bfq_find_rq_fmerge(struct bfq_data *bfqd, struct bfq_queue *bfqq; bic = bfq_bic_lookup(bfqd, tsk->io_context); - if (bic == NULL) + if (!bic) return NULL; bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); - if (bfqq != NULL) + if (bfqq) return elv_rb_find(&bfqq->sort_list, bio_end_sector(bio)); return NULL; @@ -1068,8 +1092,7 @@ static void bfq_activate_request(struct request_queue *q, struct request *rq) (long long unsigned)bfqd->last_position); } -static inline void bfq_deactivate_request(struct request_queue *q, - struct request *rq) +static void bfq_deactivate_request(struct request_queue *q, struct request *rq) { struct bfq_data *bfqd = q->elevator->elevator_data; @@ -1101,7 +1124,7 @@ static void bfq_remove_request(struct request *rq) /* * Remove queue from request-position tree as it is empty. */ - if (bfqq->pos_root != NULL) { + if (bfqq->pos_root) { rb_erase(&bfqq->pos_node, bfqq->pos_root); bfqq->pos_root = NULL; } @@ -1111,6 +1134,9 @@ static void bfq_remove_request(struct request *rq) BUG_ON(bfqq->meta_pending == 0); bfqq->meta_pending--; } +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_io_remove(bfqq_group(bfqq), rq->cmd_flags); +#endif } static int bfq_merge(struct request_queue *q, struct request **req, @@ -1120,7 +1146,7 @@ static int bfq_merge(struct request_queue *q, struct request **req, struct request *__rq; __rq = bfq_find_rq_fmerge(bfqd, bio); - if (__rq != NULL && elv_rq_merge_ok(__rq, bio)) { + if (__rq && elv_rq_merge_ok(__rq, bio)) { *req = __rq; return ELEVATOR_FRONT_MERGE; } @@ -1147,7 +1173,7 @@ static void bfq_merged_request(struct request_queue *q, struct request *req, prev = bfqq->next_rq; next_rq = bfq_choose_req(bfqd, bfqq->next_rq, req, bfqd->last_position); - BUG_ON(next_rq == NULL); + BUG_ON(!next_rq); bfqq->next_rq = next_rq; /* * If next_rq changes, update both the queue's budget to @@ -1156,11 +1182,19 @@ static void bfq_merged_request(struct request_queue *q, struct request *req, */ if (prev != bfqq->next_rq) { bfq_updated_next_req(bfqd, bfqq); - bfq_rq_pos_tree_add(bfqd, bfqq); + bfq_pos_tree_add_move(bfqd, bfqq); } } } +#ifdef CONFIG_BFQ_GROUP_IOSCHED +static void bfq_bio_merged(struct request_queue *q, struct request *req, + struct bio *bio) +{ + bfqg_stats_update_io_merged(bfqq_group(RQ_BFQQ(req)), bio->bi_rw); +} +#endif + static void bfq_merged_requests(struct request_queue *q, struct request *rq, struct request *next) { @@ -1187,18 +1221,21 @@ static void bfq_merged_requests(struct request_queue *q, struct request *rq, bfqq->next_rq = rq; bfq_remove_request(next); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_io_merged(bfqq_group(bfqq), next->cmd_flags); +#endif } /* Must be called with bfqq != NULL */ -static inline void bfq_bfqq_end_wr(struct bfq_queue *bfqq) +static void bfq_bfqq_end_wr(struct bfq_queue *bfqq) { - BUG_ON(bfqq == NULL); + BUG_ON(!bfqq); if (bfq_bfqq_busy(bfqq)) bfqq->bfqd->wr_busy_queues--; bfqq->wr_coeff = 1; bfqq->wr_cur_max_time = 0; /* Trigger a weight change on the next activation of the queue */ - bfqq->entity.ioprio_changed = 1; + bfqq->entity.prio_changed = 1; } static void bfq_end_wr_async_queues(struct bfq_data *bfqd, @@ -1208,9 +1245,9 @@ static void bfq_end_wr_async_queues(struct bfq_data *bfqd, for (i = 0; i < 2; i++) for (j = 0; j < IOPRIO_BE_NR; j++) - if (bfqg->async_bfqq[i][j] != NULL) + if (bfqg->async_bfqq[i][j]) bfq_bfqq_end_wr(bfqg->async_bfqq[i][j]); - if (bfqg->async_idle_bfqq != NULL) + if (bfqg->async_idle_bfqq) bfq_bfqq_end_wr(bfqg->async_idle_bfqq); } @@ -1229,7 +1266,7 @@ static void bfq_end_wr(struct bfq_data *bfqd) spin_unlock_irq(bfqd->queue->queue_lock); } -static inline sector_t bfq_io_struct_pos(void *io_struct, bool request) +static sector_t bfq_io_struct_pos(void *io_struct, bool request) { if (request) return blk_rq_pos(io_struct); @@ -1237,25 +1274,18 @@ static inline sector_t bfq_io_struct_pos(void *io_struct, bool request) return ((struct bio *)io_struct)->bi_iter.bi_sector; } -static inline sector_t bfq_dist_from(sector_t pos1, - sector_t pos2) -{ - if (pos1 >= pos2) - return pos1 - pos2; - else - return pos2 - pos1; -} - -static inline int bfq_rq_close_to_sector(void *io_struct, bool request, - sector_t sector) +static int bfq_rq_close_to_sector(void *io_struct, bool request, + sector_t sector) { - return bfq_dist_from(bfq_io_struct_pos(io_struct, request), sector) <= + return abs64(bfq_io_struct_pos(io_struct, request) - sector) <= BFQQ_SEEK_THR; } -static struct bfq_queue *bfqq_close(struct bfq_data *bfqd, sector_t sector) +static struct bfq_queue *bfqq_find_close(struct bfq_data *bfqd, + struct bfq_queue *bfqq, + sector_t sector) { - struct rb_root *root = &bfqd->rq_pos_tree; + struct rb_root *root = &bfq_bfqq_to_bfqg(bfqq)->rq_pos_tree; struct rb_node *parent, *node; struct bfq_queue *__bfqq; @@ -1267,7 +1297,7 @@ static struct bfq_queue *bfqq_close(struct bfq_data *bfqd, sector_t sector) * request, choose it. */ __bfqq = bfq_rq_pos_tree_lookup(bfqd, root, sector, &parent, NULL); - if (__bfqq != NULL) + if (__bfqq) return __bfqq; /* @@ -1283,7 +1313,7 @@ static struct bfq_queue *bfqq_close(struct bfq_data *bfqd, sector_t sector) node = rb_next(&__bfqq->pos_node); else node = rb_prev(&__bfqq->pos_node); - if (node == NULL) + if (!node) return NULL; __bfqq = rb_entry(node, struct bfq_queue, pos_node); @@ -1293,56 +1323,19 @@ static struct bfq_queue *bfqq_close(struct bfq_data *bfqd, sector_t sector) return NULL; } -/* - * bfqd - obvious - * cur_bfqq - passed in so that we don't decide that the current queue - * is closely cooperating with itself - * sector - used as a reference point to search for a close queue - */ -static struct bfq_queue *bfq_close_cooperator(struct bfq_data *bfqd, - struct bfq_queue *cur_bfqq, - sector_t sector) +static struct bfq_queue *bfq_find_close_cooperator(struct bfq_data *bfqd, + struct bfq_queue *cur_bfqq, + sector_t sector) { struct bfq_queue *bfqq; - if (bfq_class_idle(cur_bfqq)) - return NULL; - if (!bfq_bfqq_sync(cur_bfqq)) - return NULL; - if (BFQQ_SEEKY(cur_bfqq)) - return NULL; - - /* If device has only one backlogged bfq_queue, don't search. */ - if (bfqd->busy_queues == 1) - return NULL; - /* * We should notice if some of the queues are cooperating, e.g. * working closely on the same area of the disk. In that case, * we can group them together and don't waste time idling. */ - bfqq = bfqq_close(bfqd, sector); - if (bfqq == NULL || bfqq == cur_bfqq) - return NULL; - - /* - * Do not merge queues from different bfq_groups. - */ - if (bfqq->entity.parent != cur_bfqq->entity.parent) - return NULL; - - /* - * It only makes sense to merge sync queues. - */ - if (!bfq_bfqq_sync(bfqq)) - return NULL; - if (BFQQ_SEEKY(bfqq)) - return NULL; - - /* - * Do not merge queues of different priority classes. - */ - if (bfq_class_rt(bfqq) != bfq_class_rt(cur_bfqq)) + bfqq = bfqq_find_close(bfqd, cur_bfqq, sector); + if (!bfqq || bfqq == cur_bfqq) return NULL; return bfqq; @@ -1409,6 +1402,35 @@ bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) return new_bfqq; } +static bool bfq_may_be_close_cooperator(struct bfq_queue *bfqq, + struct bfq_queue *new_bfqq) +{ + if (WARN_ON(bfqq->entity.parent != new_bfqq->entity.parent)) + return false; + + if (bfq_class_idle(bfqq) || bfq_class_idle(new_bfqq) || + (bfqq->ioprio_class != new_bfqq->ioprio_class)) + return false; + + /* + * If either of the queues has already been detected as seeky, + * then merging it with the other queue is unlikely to lead to + * sequential I/O. + */ + if (BFQQ_SEEKY(bfqq) || BFQQ_SEEKY(new_bfqq)) + return false; + + /* + * Interleaved I/O is known to be done by (some) applications + * only for reads, so it does not make sense to merge async + * queues. + */ + if (!bfq_bfqq_sync(bfqq) || !bfq_bfqq_sync(new_bfqq)) + return false; + + return true; +} + /* * Attempt to schedule a merge of bfqq with the currently in-service queue * or with a close queue among the scheduled queues. @@ -1430,56 +1452,48 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (bfqq->new_bfqq) return bfqq->new_bfqq; - if (!io_struct || unlikely(bfqq == &bfqd->oom_bfqq)) return NULL; + /* If device has only one backlogged bfq_queue, don't search. */ + if (bfqd->busy_queues == 1) + return NULL; in_service_bfqq = bfqd->in_service_queue; - if (in_service_bfqq == NULL || in_service_bfqq == bfqq || + if (!in_service_bfqq || in_service_bfqq == bfqq || !bfqd->in_service_bic || unlikely(in_service_bfqq == &bfqd->oom_bfqq)) goto check_scheduled; - if (bfq_class_idle(in_service_bfqq) || bfq_class_idle(bfqq)) - goto check_scheduled; - - if (bfq_class_rt(in_service_bfqq) != bfq_class_rt(bfqq)) - goto check_scheduled; - - if (in_service_bfqq->entity.parent != bfqq->entity.parent) - goto check_scheduled; - if (bfq_rq_close_to_sector(io_struct, request, bfqd->last_position) && - bfq_bfqq_sync(in_service_bfqq) && bfq_bfqq_sync(bfqq)) { + bfq_may_be_close_cooperator(bfqq, in_service_bfqq)) { new_bfqq = bfq_setup_merge(bfqq, in_service_bfqq); - if (new_bfqq != NULL) - return new_bfqq; /* Merge with in-service queue */ + if (new_bfqq) + return new_bfqq; } - /* * Check whether there is a cooperator among currently scheduled * queues. The only thing we need is that the bio/request is not * NULL, as we need it to establish whether a cooperator exists. */ check_scheduled: - new_bfqq = bfq_close_cooperator(bfqd, bfqq, - bfq_io_struct_pos(io_struct, request)); - if (new_bfqq && likely(new_bfqq != &bfqd->oom_bfqq)) + new_bfqq = bfq_find_close_cooperator(bfqd, bfqq, + bfq_io_struct_pos(io_struct, request)); + if (new_bfqq && likely(new_bfqq != &bfqd->oom_bfqq) && + bfq_may_be_close_cooperator(bfqq, new_bfqq)) return bfq_setup_merge(bfqq, new_bfqq); return NULL; } -static inline void -bfq_bfqq_save_state(struct bfq_queue *bfqq) +static void bfq_bfqq_save_state(struct bfq_queue *bfqq) { /* - * If bfqq->bic == NULL, the queue is already shared or its requests + * If !bfqq->bic, the queue is already shared or its requests * have already been redirected to a shared queue; both idle window * and weight raising state have already been saved. Do nothing. */ - if (bfqq->bic == NULL) + if (!bfqq->bic) return; if (bfqq->bic->wr_time_left) /* @@ -1523,8 +1537,7 @@ bfq_bfqq_save_state(struct bfq_queue *bfqq) bfqq->bic->failed_cooperations = 0; } -static inline void -bfq_get_bic_reference(struct bfq_queue *bfqq) +static void bfq_get_bic_reference(struct bfq_queue *bfqq) { /* * If bfqq->bic has a non-NULL value, the bic to which it belongs @@ -1572,7 +1585,7 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic, bfq_put_queue(bfqq); } -static inline void bfq_bfqq_increase_failed_cooperations(struct bfq_queue *bfqq) +static void bfq_bfqq_increase_failed_cooperations(struct bfq_queue *bfqq) { struct bfq_io_cq *bic = bfqq->bic; struct bfq_data *bfqd = bfqq->bfqd; @@ -1603,7 +1616,7 @@ static int bfq_allow_merge(struct request_queue *q, struct request *rq, * Queue lock is held here. */ bic = bfq_bic_lookup(bfqd, current->io_context); - if (bic == NULL) + if (!bic) return 0; bfqq = bic_to_bfqq(bic, bfq_bio_sync(bio)); @@ -1611,9 +1624,9 @@ static int bfq_allow_merge(struct request_queue *q, struct request *rq, * We take advantage of this function to perform an early merge * of the queues of possible cooperating processes. */ - if (bfqq != NULL) { + if (bfqq) { new_bfqq = bfq_setup_cooperator(bfqd, bfqq, bio, false); - if (new_bfqq != NULL) { + if (new_bfqq) { bfq_merge_bfqqs(bfqd, bic, bfqq, new_bfqq); /* * If we get here, the bio will be queued in the @@ -1631,7 +1644,10 @@ static int bfq_allow_merge(struct request_queue *q, struct request *rq, static void __bfq_set_in_service_queue(struct bfq_data *bfqd, struct bfq_queue *bfqq) { - if (bfqq != NULL) { + if (bfqq) { +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_avg_queue_size(bfqq_group(bfqq)); +#endif bfq_mark_bfqq_must_alloc(bfqq); bfq_mark_bfqq_budget_new(bfqq); bfq_clear_bfqq_fifo_expire(bfqq); @@ -1639,7 +1655,7 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd, bfqd->budgets_assigned = (bfqd->budgets_assigned*7 + 256) / 8; bfq_log_bfqq(bfqd, bfqq, - "set_in_service_queue, cur-budget = %lu", + "set_in_service_queue, cur-budget = %d", bfqq->entity.budget); } @@ -1662,9 +1678,9 @@ static struct bfq_queue *bfq_set_in_service_queue(struct bfq_data *bfqd) * stored in bfqd, which is dynamically updated according to the * estimated disk peak rate; otherwise return the default max budget */ -static inline unsigned long bfq_max_budget(struct bfq_data *bfqd) +static int bfq_max_budget(struct bfq_data *bfqd) { - if (bfqd->budgets_assigned < 194) + if (bfqd->budgets_assigned < bfq_stats_min_budgets) return bfq_default_max_budget; else return bfqd->bfq_max_budget; @@ -1674,9 +1690,9 @@ static inline unsigned long bfq_max_budget(struct bfq_data *bfqd) * Return min budget, which is a fraction of the current or default * max budget (trying with 1/32) */ -static inline unsigned long bfq_min_budget(struct bfq_data *bfqd) +static int bfq_min_budget(struct bfq_data *bfqd) { - if (bfqd->budgets_assigned < 194) + if (bfqd->budgets_assigned < bfq_stats_min_budgets) return bfq_default_max_budget / 32; else return bfqd->bfq_max_budget / 32; @@ -1692,7 +1708,7 @@ static void bfq_arm_slice_timer(struct bfq_data *bfqd) /* Processes have exited, don't wait. */ bic = bfqd->in_service_bic; - if (bic == NULL || atomic_read(&bic->icq.ioc->active_ref) == 0) + if (!bic || atomic_read(&bic->icq.ioc->active_ref) == 0) return; bfq_mark_bfqq_wait_request(bfqq); @@ -1718,12 +1734,15 @@ static void bfq_arm_slice_timer(struct bfq_data *bfqd) ((BFQQ_SEEKY(bfqq) && bfqq->entity.service > bfq_max_budget(bfqq->bfqd) / 8) || bfq_bfqq_constantly_seeky(bfqq)) && bfqq->wr_coeff == 1 && - symmetric_scenario) + bfq_symmetric_scenario(bfqd)) sl = min(sl, msecs_to_jiffies(BFQ_MIN_TT)); else if (bfqq->wr_coeff > 1) sl = sl * 3; bfqd->last_idling_start = ktime_get(); mod_timer(&bfqd->idle_slice_timer, jiffies + sl); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_set_start_idle_time(bfqq_group(bfqq)); +#endif bfq_log(bfqd, "arm idle: %u/%u ms", jiffies_to_msecs(sl), jiffies_to_msecs(bfqd->bfq_slice_idle)); } @@ -1777,6 +1796,10 @@ static void bfq_dispatch_insert(struct request_queue *q, struct request *rq) if (bfq_bfqq_sync(bfqq)) bfqd->sync_flight++; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_dispatch(bfqq_group(bfqq), blk_rq_bytes(rq), + rq->cmd_flags); +#endif } /* @@ -1802,7 +1825,7 @@ static struct request *bfq_check_fifo(struct bfq_queue *bfqq) return rq; } -static inline unsigned long bfq_bfqq_budget_left(struct bfq_queue *bfqq) +static int bfq_bfqq_budget_left(struct bfq_queue *bfqq) { struct bfq_entity *entity = &bfqq->entity; return entity->budget - entity->service; @@ -1836,7 +1859,7 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) /* * Resort priority tree of potential close cooperators. */ - bfq_rq_pos_tree_add(bfqd, bfqq); + bfq_pos_tree_add_move(bfqd, bfqq); } } @@ -1846,24 +1869,24 @@ static void __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq) * @bfqq: queue to update. * @reason: reason for expiration. * - * Handle the feedback on @bfqq budget. See the body for detailed - * comments. + * Handle the feedback on @bfqq budget at queue expiration. + * See the body for detailed comments. */ static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, struct bfq_queue *bfqq, enum bfqq_expiration reason) { struct request *next_rq; - unsigned long budget, min_budget; + int budget, min_budget; budget = bfqq->max_budget; min_budget = bfq_min_budget(bfqd); BUG_ON(bfqq != bfqd->in_service_queue); - bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %lu, budg left %lu", + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last budg %d, budg left %d", bfqq->entity.budget, bfq_bfqq_budget_left(bfqq)); - bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %lu, min budg %lu", + bfq_log_bfqq(bfqd, bfqq, "recalc_budg: last max_budg %d, min budg %d", budget, bfq_min_budget(bfqd)); bfq_log_bfqq(bfqd, bfqq, "recalc_budg: sync %d, seeky %d", bfq_bfqq_sync(bfqq), BFQQ_SEEKY(bfqd->in_service_queue)); @@ -1940,18 +1963,19 @@ static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, default: return; } - } else /* async queue */ - /* async queues get always the maximum possible budget - * (their ability to dispatch is limited by - * @bfqd->bfq_max_budget_async_rq). - */ + } else + /* + * Async queues get always the maximum possible budget + * (their ability to dispatch is limited by + * @bfqd->bfq_max_budget_async_rq). + */ budget = bfqd->bfq_max_budget; bfqq->max_budget = budget; - if (bfqd->budgets_assigned >= 194 && bfqd->bfq_user_max_budget == 0 && - bfqq->max_budget > bfqd->bfq_max_budget) - bfqq->max_budget = bfqd->bfq_max_budget; + if (bfqd->budgets_assigned >= bfq_stats_min_budgets && + !bfqd->bfq_user_max_budget) + bfqq->max_budget = min(bfqq->max_budget, bfqd->bfq_max_budget); /* * Make sure that we have enough budget for the next request. @@ -1960,14 +1984,14 @@ static void __bfq_bfqq_recalc_budget(struct bfq_data *bfqd, * update. */ next_rq = bfqq->next_rq; - if (next_rq != NULL) + if (next_rq) bfqq->entity.budget = max_t(unsigned long, bfqq->max_budget, bfq_serv_to_charge(next_rq, bfqq)); else bfqq->entity.budget = bfqq->max_budget; - bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %lu", - next_rq != NULL ? blk_rq_sectors(next_rq) : 0, + bfq_log_bfqq(bfqd, bfqq, "head sect: %u, new budget %d", + next_rq ? blk_rq_sectors(next_rq) : 0, bfqq->entity.budget); } @@ -1993,15 +2017,15 @@ static unsigned long bfq_calc_max_budget(u64 peak_rate, u64 timeout) * seeky processes, and hence reduce their chances to lower the * throughput. See the code for more details. */ -static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, - int compensate, enum bfqq_expiration reason) +static bool bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, + bool compensate, enum bfqq_expiration reason) { u64 bw, usecs, expected, timeout; ktime_t delta; int update = 0; if (!bfq_bfqq_sync(bfqq) || bfq_bfqq_budget_new(bfqq)) - return 0; + return false; if (compensate) delta = bfqd->last_idling_start; @@ -2012,7 +2036,7 @@ static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, /* Don't trust short/unrealistic values. */ if (usecs < 100 || usecs >= LONG_MAX) - return 0; + return false; /* * Calculate the bandwidth for the last slice. We use a 64 bit @@ -2061,7 +2085,7 @@ static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, bfqd->bfq_max_budget = bfq_calc_max_budget(bfqd->peak_rate, timeout); - bfq_log(bfqd, "new max_budget=%lu", + bfq_log(bfqd, "new max_budget=%d", bfqd->bfq_max_budget); } if (bfqd->device_speed == BFQ_BFQD_FAST && @@ -2086,7 +2110,7 @@ static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, * and for the moment return false. */ if (bfqq->entity.budget <= bfq_max_budget(bfqd) / 8) - return 0; + return false; /* * A process is considered ``slow'' (i.e., seeky, so that we @@ -2161,8 +2185,8 @@ static int bfq_update_peak_rate(struct bfq_data *bfqd, struct bfq_queue *bfqq, * seems to be quite precise also in embedded systems and KVM/QEMU virtual * machines. */ -static inline unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, - struct bfq_queue *bfqq) +static unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, + struct bfq_queue *bfqq) { return max(bfqq->last_idle_bklogged + HZ * bfqq->service_from_backlogged / @@ -2175,7 +2199,7 @@ static inline unsigned long bfq_bfqq_softrt_next_start(struct bfq_data *bfqd, * the current time will be lower than this time instant according to the macro * time_is_before_jiffies(). */ -static inline unsigned long bfq_infinity_from_now(unsigned long now) +static unsigned long bfq_infinity_from_now(unsigned long now) { return now + ULONG_MAX / 2; } @@ -2212,13 +2236,14 @@ static inline unsigned long bfq_infinity_from_now(unsigned long now) */ static void bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, - int compensate, + bool compensate, enum bfqq_expiration reason) { - int slow; + bool slow; BUG_ON(bfqq != bfqd->in_service_queue); - /* Update disk peak rate for autotuning and check whether the + /* + * Update disk peak rate for autotuning and check whether the * process is slow (see bfq_update_peak_rate). */ slow = bfq_update_peak_rate(bfqd, bfqq, compensate, reason); @@ -2312,12 +2337,12 @@ static void bfq_bfqq_expire(struct bfq_data *bfqd, * just checked on request arrivals and completions, as well as on * idle timer expirations. */ -static int bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) +static bool bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) { if (bfq_bfqq_budget_new(bfqq) || time_before(jiffies, bfqq->budget_timeout)) - return 0; - return 1; + return false; + return true; } /* @@ -2328,7 +2353,7 @@ static int bfq_bfqq_budget_timeout(struct bfq_queue *bfqq) * does not hold, or if the queue is slow enough to deserve only to be * kicked off for preserving a high throughput. */ -static inline int bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) +static bool bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) { bfq_log_bfqq(bfqq->bfqd, bfqq, "may_budget_timeout: wait_request %d left %d timeout %d", @@ -2343,183 +2368,278 @@ static inline int bfq_may_expire_for_budg_timeout(struct bfq_queue *bfqq) } /* - * Device idling is allowed only for the queues for which this function - * returns true. For this reason, the return value of this function plays a - * critical role for both throughput boosting and service guarantees. The - * return value is computed through a logical expression. In this rather - * long comment, we try to briefly describe all the details and motivations - * behind the components of this logical expression. - * - * First, the expression is false if bfqq is not sync, or if: bfqq happened - * to become active during a large burst of queue activations, and the - * pattern of requests bfqq contains boosts the throughput if bfqq is - * expired. In fact, queues that became active during a large burst benefit - * only from throughput, as discussed in the comments to bfq_handle_burst. - * In this respect, expiring bfqq certainly boosts the throughput on NCQ- - * capable flash-based devices, whereas, on rotational devices, it boosts - * the throughput only if bfqq contains random requests. - * - * On the opposite end, if (a) bfqq is sync, (b) the above burst-related - * condition does not hold, and (c) bfqq is being weight-raised, then the - * expression always evaluates to true, as device idling is instrumental - * for preserving low-latency guarantees (see [1]). If, instead, conditions - * (a) and (b) do hold, but (c) does not, then the expression evaluates to - * true only if: (1) bfqq is I/O-bound and has a non-null idle window, and - * (2) at least one of the following two conditions holds. - * The first condition is that the device is not performing NCQ, because - * idling the device most certainly boosts the throughput if this condition - * holds and bfqq is I/O-bound and has been granted a non-null idle window. - * The second compound condition is made of the logical AND of two components. - * - * The first component is true only if there is no weight-raised busy - * queue. This guarantees that the device is not idled for a sync non- - * weight-raised queue when there are busy weight-raised queues. The former - * is then expired immediately if empty. Combined with the timestamping - * rules of BFQ (see [1] for details), this causes sync non-weight-raised - * queues to get a lower number of requests served, and hence to ask for a - * lower number of requests from the request pool, before the busy weight- - * raised queues get served again. - * - * This is beneficial for the processes associated with weight-raised - * queues, when the request pool is saturated (e.g., in the presence of - * write hogs). In fact, if the processes associated with the other queues - * ask for requests at a lower rate, then weight-raised processes have a - * higher probability to get a request from the pool immediately (or at - * least soon) when they need one. Hence they have a higher probability to - * actually get a fraction of the disk throughput proportional to their - * high weight. This is especially true with NCQ-capable drives, which - * enqueue several requests in advance and further reorder internally- - * queued requests. - * - * In the end, mistreating non-weight-raised queues when there are busy - * weight-raised queues seems to mitigate starvation problems in the - * presence of heavy write workloads and NCQ, and hence to guarantee a - * higher application and system responsiveness in these hostile scenarios. - * - * If the first component of the compound condition is instead true, i.e., - * there is no weight-raised busy queue, then the second component of the - * compound condition takes into account service-guarantee and throughput - * issues related to NCQ (recall that the compound condition is evaluated - * only if the device is detected as supporting NCQ). + * For a queue that becomes empty, device idling is allowed only if + * this function returns true for that queue. As a consequence, since + * device idling plays a critical role for both throughput boosting + * and service guarantees, the return value of this function plays a + * critical role as well. * - * As for service guarantees, allowing the drive to enqueue more than one - * request at a time, and hence delegating de facto final scheduling - * decisions to the drive's internal scheduler, causes loss of control on - * the actual request service order. In this respect, when the drive is - * allowed to enqueue more than one request at a time, the service - * distribution enforced by the drive's internal scheduler is likely to - * coincide with the desired device-throughput distribution only in the - * following, perfectly symmetric, scenario: - * 1) all active queues have the same weight, - * 2) all active groups at the same level in the groups tree have the same - * weight, - * 3) all active groups at the same level in the groups tree have the same - * number of children. - * - * Even in such a scenario, sequential I/O may still receive a preferential - * treatment, but this is not likely to be a big issue with flash-based - * devices, because of their non-dramatic loss of throughput with random - * I/O. Things do differ with HDDs, for which additional care is taken, as - * explained after completing the discussion for flash-based devices. + * In a nutshell, this function returns true only if idling is + * beneficial for throughput or, even if detrimental for throughput, + * idling is however necessary to preserve service guarantees (low + * latency, desired throughput distribution, ...). In particular, on + * NCQ-capable devices, this function tries to return false, so as to + * help keep the drives' internal queues full, whenever this helps the + * device boost the throughput without causing any service-guarantee + * issue. * - * Unfortunately, keeping the necessary state for evaluating exactly the - * above symmetry conditions would be quite complex and time-consuming. - * Therefore BFQ evaluates instead the following stronger sub-conditions, - * for which it is much easier to maintain the needed state: - * 1) all active queues have the same weight, - * 2) all active groups have the same weight, - * 3) all active groups have at most one active child each. - * In particular, the last two conditions are always true if hierarchical - * support and the cgroups interface are not enabled, hence no state needs - * to be maintained in this case. - * - * According to the above considerations, the second component of the - * compound condition evaluates to true if any of the above symmetry - * sub-condition does not hold, or the device is not flash-based. Therefore, - * if also the first component is true, then idling is allowed for a sync - * queue. These are the only sub-conditions considered if the device is - * flash-based, as, for such a device, it is sensible to force idling only - * for service-guarantee issues. In fact, as for throughput, idling - * NCQ-capable flash-based devices would not boost the throughput even - * with sequential I/O; rather it would lower the throughput in proportion - * to how fast the device is. In the end, (only) if all the three - * sub-conditions hold and the device is flash-based, the compound - * condition evaluates to false and therefore no idling is performed. - * - * As already said, things change with a rotational device, where idling - * boosts the throughput with sequential I/O (even with NCQ). Hence, for - * such a device the second component of the compound condition evaluates - * to true also if the following additional sub-condition does not hold: - * the queue is constantly seeky. Unfortunately, this different behavior - * with respect to flash-based devices causes an additional asymmetry: if - * some sync queues enjoy idling and some other sync queues do not, then - * the latter get a low share of the device throughput, simply because the - * former get many requests served after being set as in service, whereas - * the latter do not. As a consequence, to guarantee the desired throughput - * distribution, on HDDs the compound expression evaluates to true (and - * hence device idling is performed) also if the following last symmetry - * condition does not hold: no other queue is benefiting from idling. Also - * this last condition is actually replaced with a simpler-to-maintain and - * stronger condition: there is no busy queue which is not constantly seeky - * (and hence may also benefit from idling). - * - * To sum up, when all the required symmetry and throughput-boosting - * sub-conditions hold, the second component of the compound condition - * evaluates to false, and hence no idling is performed. This helps to - * keep the drives' internal queues full on NCQ-capable devices, and hence - * to boost the throughput, without causing 'almost' any loss of service - * guarantees. The 'almost' follows from the fact that, if the internal - * queue of one such device is filled while all the sub-conditions hold, - * but at some point in time some sub-condition stops to hold, then it may - * become impossible to let requests be served in the new desired order - * until all the requests already queued in the device have been served. + * In more detail, the return value of this function is obtained by, + * first, computing a number of boolean variables that take into + * account throughput and service-guarantee issues, and, then, + * combining these variables in a logical expression. Most of the + * issues taken into account are not trivial. We discuss these issues + * while introducing the variables. */ -static inline bool bfq_bfqq_must_not_expire(struct bfq_queue *bfqq) +static bool bfq_bfqq_may_idle(struct bfq_queue *bfqq) { struct bfq_data *bfqd = bfqq->bfqd; -#define cond_for_seeky_on_ncq_hdd (bfq_bfqq_constantly_seeky(bfqq) && \ - bfqd->busy_in_flight_queues == \ - bfqd->const_seeky_busy_in_flight_queues) + bool idling_boosts_thr, idling_boosts_thr_without_issues, + all_queues_seeky, on_hdd_and_not_all_queues_seeky, + idling_needed_for_service_guarantees, + asymmetric_scenario; -#define cond_for_expiring_in_burst (bfq_bfqq_in_large_burst(bfqq) && \ - bfqd->hw_tag && \ - (blk_queue_nonrot(bfqd->queue) || \ - bfq_bfqq_constantly_seeky(bfqq))) + /* + * The next variable takes into account the cases where idling + * boosts the throughput. + * + * The value of the variable is computed considering, first, that + * idling is virtually always beneficial for the throughput if: + * (a) the device is not NCQ-capable, or + * (b) regardless of the presence of NCQ, the device is rotational + * and the request pattern for bfqq is I/O-bound and sequential. + * + * Secondly, and in contrast to the above item (b), idling an + * NCQ-capable flash-based device would not boost the + * throughput even with sequential I/O; rather it would lower + * the throughput in proportion to how fast the device + * is. Accordingly, the next variable is true if any of the + * above conditions (a) and (b) is true, and, in particular, + * happens to be false if bfqd is an NCQ-capable flash-based + * device. + */ + idling_boosts_thr = !bfqd->hw_tag || + (!blk_queue_nonrot(bfqd->queue) && bfq_bfqq_IO_bound(bfqq) && + bfq_bfqq_idle_window(bfqq)) ; -/* - * Condition for expiring a non-weight-raised queue (and hence not idling - * the device). - */ -#define cond_for_expiring_non_wr (bfqd->hw_tag && \ - (bfqd->wr_busy_queues > 0 || \ - (blk_queue_nonrot(bfqd->queue) || \ - cond_for_seeky_on_ncq_hdd))) + /* + * The value of the next variable, + * idling_boosts_thr_without_issues, is equal to that of + * idling_boosts_thr, unless a special case holds. In this + * special case, described below, idling may cause problems to + * weight-raised queues. + * + * When the request pool is saturated (e.g., in the presence + * of write hogs), if the processes associated with + * non-weight-raised queues ask for requests at a lower rate, + * then processes associated with weight-raised queues have a + * higher probability to get a request from the pool + * immediately (or at least soon) when they need one. Thus + * they have a higher probability to actually get a fraction + * of the device throughput proportional to their high + * weight. This is especially true with NCQ-capable drives, + * which enqueue several requests in advance, and further + * reorder internally-queued requests. + * + * For this reason, we force to false the value of + * idling_boosts_thr_without_issues if there are weight-raised + * busy queues. In this case, and if bfqq is not weight-raised, + * this guarantees that the device is not idled for bfqq (if, + * instead, bfqq is weight-raised, then idling will be + * guaranteed by another variable, see below). Combined with + * the timestamping rules of BFQ (see [1] for details), this + * behavior causes bfqq, and hence any sync non-weight-raised + * queue, to get a lower number of requests served, and thus + * to ask for a lower number of requests from the request + * pool, before the busy weight-raised queues get served + * again. This often mitigates starvation problems in the + * presence of heavy write workloads and NCQ, thereby + * guaranteeing a higher application and system responsiveness + * in these hostile scenarios. + */ + idling_boosts_thr_without_issues = idling_boosts_thr && + bfqd->wr_busy_queues == 0; + + /* + * There are then two cases where idling must be performed not + * for throughput concerns, but to preserve service + * guarantees. In the description of these cases, we say, for + * short, that a queue is sequential/random if the process + * associated to the queue issues sequential/random requests + * (in the second case the queue may be tagged as seeky or + * even constantly_seeky). + * + * To introduce the first case, we note that, since + * bfq_bfqq_idle_window(bfqq) is false if the device is + * NCQ-capable and bfqq is random (see + * bfq_update_idle_window()), then, from the above two + * assignments it follows that + * idling_boosts_thr_without_issues is false if the device is + * NCQ-capable and bfqq is random. Therefore, for this case, + * device idling would never be allowed if we used just + * idling_boosts_thr_without_issues to decide whether to allow + * it. And, beneficially, this would imply that throughput + * would always be boosted also with random I/O on NCQ-capable + * HDDs. + * + * But we must be careful on this point, to avoid an unfair + * treatment for bfqq. In fact, because of the same above + * assignments, idling_boosts_thr_without_issues is, on the + * other hand, true if 1) the device is an HDD and bfqq is + * sequential, and 2) there are no busy weight-raised + * queues. As a consequence, if we used just + * idling_boosts_thr_without_issues to decide whether to idle + * the device, then with an HDD we might easily bump into a + * scenario where queues that are sequential and I/O-bound + * would enjoy idling, whereas random queues would not. The + * latter might then get a low share of the device throughput, + * simply because the former would get many requests served + * after being set as in service, while the latter would not. + * + * To address this issue, we start by setting to true a + * sentinel variable, on_hdd_and_not_all_queues_seeky, if the + * device is rotational and not all queues with pending or + * in-flight requests are constantly seeky (i.e., there are + * active sequential queues, and bfqq might then be mistreated + * if it does not enjoy idling because it is random). + */ + all_queues_seeky = bfq_bfqq_constantly_seeky(bfqq) && + bfqd->busy_in_flight_queues == + bfqd->const_seeky_busy_in_flight_queues; + + on_hdd_and_not_all_queues_seeky = + !blk_queue_nonrot(bfqd->queue) && !all_queues_seeky; + + /* + * To introduce the second case where idling needs to be + * performed to preserve service guarantees, we can note that + * allowing the drive to enqueue more than one request at a + * time, and hence delegating de facto final scheduling + * decisions to the drive's internal scheduler, causes loss of + * control on the actual request service order. In particular, + * the critical situation is when requests from different + * processes happens to be present, at the same time, in the + * internal queue(s) of the drive. In such a situation, the + * drive, by deciding the service order of the + * internally-queued requests, does determine also the actual + * throughput distribution among these processes. But the + * drive typically has no notion or concern about per-process + * throughput distribution, and makes its decisions only on a + * per-request basis. Therefore, the service distribution + * enforced by the drive's internal scheduler is likely to + * coincide with the desired device-throughput distribution + * only in a completely symmetric scenario where: + * (i) each of these processes must get the same throughput as + * the others; + * (ii) all these processes have the same I/O pattern + (either sequential or random). + * In fact, in such a scenario, the drive will tend to treat + * the requests of each of these processes in about the same + * way as the requests of the others, and thus to provide + * each of these processes with about the same throughput + * (which is exactly the desired throughput distribution). In + * contrast, in any asymmetric scenario, device idling is + * certainly needed to guarantee that bfqq receives its + * assigned fraction of the device throughput (see [1] for + * details). + * + * We address this issue by controlling, actually, only the + * symmetry sub-condition (i), i.e., provided that + * sub-condition (i) holds, idling is not performed, + * regardless of whether sub-condition (ii) holds. In other + * words, only if sub-condition (i) holds, then idling is + * allowed, and the device tends to be prevented from queueing + * many requests, possibly of several processes. The reason + * for not controlling also sub-condition (ii) is that, first, + * in the case of an HDD, the asymmetry in terms of types of + * I/O patterns is already taken in to account in the above + * sentinel variable + * on_hdd_and_not_all_queues_seeky. Secondly, in the case of a + * flash-based device, we prefer however to privilege + * throughput (and idling lowers throughput for this type of + * devices), for the following reasons: + * 1) differently from HDDs, the service time of random + * requests is not orders of magnitudes lower than the service + * time of sequential requests; thus, even if processes doing + * sequential I/O get a preferential treatment with respect to + * others doing random I/O, the consequences are not as + * dramatic as with HDDs; + * 2) if a process doing random I/O does need strong + * throughput guarantees, it is hopefully already being + * weight-raised, or the user is likely to have assigned it a + * higher weight than the other processes (and thus + * sub-condition (i) is likely to be false, which triggers + * idling). + * + * According to the above considerations, the next variable is + * true (only) if sub-condition (i) holds. To compute the + * value of this variable, we not only use the return value of + * the function bfq_symmetric_scenario(), but also check + * whether bfqq is being weight-raised, because + * bfq_symmetric_scenario() does not take into account also + * weight-raised queues (see comments to + * bfq_weights_tree_add()). + * + * As a side note, it is worth considering that the above + * device-idling countermeasures may however fail in the + * following unlucky scenario: if idling is (correctly) + * disabled in a time period during which all symmetry + * sub-conditions hold, and hence the device is allowed to + * enqueue many requests, but at some later point in time some + * sub-condition stops to hold, then it may become impossible + * to let requests be served in the desired order until all + * the requests already queued in the device have been served. + */ + asymmetric_scenario = bfqq->wr_coeff > 1 || + !bfq_symmetric_scenario(bfqd); + + /* + * Finally, there is a case where maximizing throughput is the + * best choice even if it may cause unfairness toward + * bfqq. Such a case is when bfqq became active in a burst of + * queue activations. Queues that became active during a large + * burst benefit only from throughput, as discussed in the + * comments to bfq_handle_burst. Thus, if bfqq became active + * in a burst and not idling the device maximizes throughput, + * then the device must no be idled, because not idling the + * device provides bfqq and all other queues in the burst with + * maximum benefit. Combining this and the two cases above, we + * can now establish when idling is actually needed to + * preserve service guarantees. + */ + idling_needed_for_service_guarantees = + (on_hdd_and_not_all_queues_seeky || asymmetric_scenario) && + !bfq_bfqq_in_large_burst(bfqq); + /* + * We have now all the components we need to compute the return + * value of the function, which is true only if both the following + * conditions hold: + * 1) bfqq is sync, because idling make sense only for sync queues; + * 2) idling either boosts the throughput (without issues), or + * is necessary to preserve service guarantees. + */ return bfq_bfqq_sync(bfqq) && - !cond_for_expiring_in_burst && - (bfqq->wr_coeff > 1 || !symmetric_scenario || - (bfq_bfqq_IO_bound(bfqq) && bfq_bfqq_idle_window(bfqq) && - !cond_for_expiring_non_wr) - ); + (idling_boosts_thr_without_issues || + idling_needed_for_service_guarantees); } /* - * If the in-service queue is empty but sync, and the function - * bfq_bfqq_must_not_expire returns true, then: + * If the in-service queue is empty but the function bfq_bfqq_may_idle + * returns true, then: * 1) the queue must remain in service and cannot be expired, and - * 2) the disk must be idled to wait for the possible arrival of a new + * 2) the device must be idled to wait for the possible arrival of a new * request for the queue. - * See the comments to the function bfq_bfqq_must_not_expire for the reasons + * See the comments to the function bfq_bfqq_may_idle for the reasons * why performing device idling is the best choice to boost the throughput - * and preserve service guarantees when bfq_bfqq_must_not_expire itself + * and preserve service guarantees when bfq_bfqq_may_idle itself * returns true. */ -static inline bool bfq_bfqq_must_idle(struct bfq_queue *bfqq) +static bool bfq_bfqq_must_idle(struct bfq_queue *bfqq) { struct bfq_data *bfqd = bfqq->bfqd; return RB_EMPTY_ROOT(&bfqq->sort_list) && bfqd->bfq_slice_idle != 0 && - bfq_bfqq_must_not_expire(bfqq); + bfq_bfqq_may_idle(bfqq); } /* @@ -2533,7 +2653,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) enum bfqq_expiration reason = BFQ_BFQQ_BUDGET_TIMEOUT; bfqq = bfqd->in_service_queue; - if (bfqq == NULL) + if (!bfqq) goto new_queue; bfq_log_bfqq(bfqd, bfqq, "select_queue: already in-service queue"); @@ -2548,7 +2668,7 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) * If bfqq has requests queued and it has enough budget left to * serve them, keep the queue, otherwise expire it. */ - if (next_rq != NULL) { + if (next_rq) { if (bfq_serv_to_charge(next_rq, bfqq) > bfq_bfqq_budget_left(bfqq)) { reason = BFQ_BFQQ_BUDGET_EXHAUSTED; @@ -2575,6 +2695,9 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) */ bfq_clear_bfqq_wait_request(bfqq); del_timer(&bfqd->idle_slice_timer); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_idle_time(bfqq_group(bfqq)); +#endif } goto keep_queue; } @@ -2586,18 +2709,18 @@ static struct bfq_queue *bfq_select_queue(struct bfq_data *bfqd) * may idle after their completion, then keep it anyway. */ if (timer_pending(&bfqd->idle_slice_timer) || - (bfqq->dispatched != 0 && bfq_bfqq_must_not_expire(bfqq))) { + (bfqq->dispatched != 0 && bfq_bfqq_may_idle(bfqq))) { bfqq = NULL; goto keep_queue; } reason = BFQ_BFQQ_NO_MORE_REQUESTS; expire: - bfq_bfqq_expire(bfqd, bfqq, 0, reason); + bfq_bfqq_expire(bfqd, bfqq, false, reason); new_queue: bfqq = bfq_set_in_service_queue(bfqd); bfq_log(bfqd, "select_queue: new queue %d returned", - bfqq != NULL ? bfqq->pid : 0); + bfqq ? bfqq->pid : 0); keep_queue: return bfqq; } @@ -2615,7 +2738,7 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) BUG_ON(bfqq != bfqd->in_service_queue && entity->weight != entity->orig_weight * bfqq->wr_coeff); - if (entity->ioprio_changed) + if (entity->prio_changed) bfq_log_bfqq(bfqd, bfqq, "WARN: pending prio change"); /* @@ -2659,7 +2782,7 @@ static int bfq_dispatch_request(struct bfq_data *bfqd, /* Follow expired path, else get first next available. */ rq = bfq_check_fifo(bfqq); - if (rq == NULL) + if (!rq) rq = bfqq->next_rq; service_to_charge = bfq_serv_to_charge(rq, bfqq); @@ -2695,14 +2818,14 @@ static int bfq_dispatch_request(struct bfq_data *bfqd, bfq_update_wr_data(bfqd, bfqq); bfq_log_bfqq(bfqd, bfqq, - "dispatched %u sec req (%llu), budg left %lu", + "dispatched %u sec req (%llu), budg left %d", blk_rq_sectors(rq), (long long unsigned)blk_rq_pos(rq), bfq_bfqq_budget_left(bfqq)); dispatched++; - if (bfqd->in_service_bic == NULL) { + if (!bfqd->in_service_bic) { atomic_long_inc(&RQ_BIC(rq)->icq.ioc->refcount); bfqd->in_service_bic = RQ_BIC(rq); } @@ -2715,7 +2838,7 @@ static int bfq_dispatch_request(struct bfq_data *bfqd, return dispatched; expire: - bfq_bfqq_expire(bfqd, bfqq, 0, BFQ_BFQQ_BUDGET_EXHAUSTED); + bfq_bfqq_expire(bfqd, bfqq, false, BFQ_BFQQ_BUDGET_EXHAUSTED); return dispatched; } @@ -2723,7 +2846,7 @@ static int __bfq_forced_dispatch_bfqq(struct bfq_queue *bfqq) { int dispatched = 0; - while (bfqq->next_rq != NULL) { + while (bfqq->next_rq) { bfq_dispatch_insert(bfqq->bfqd->queue, bfqq->next_rq); dispatched++; } @@ -2743,7 +2866,7 @@ static int bfq_forced_dispatch(struct bfq_data *bfqd) int dispatched = 0; bfqq = bfqd->in_service_queue; - if (bfqq != NULL) + if (bfqq) __bfq_bfqq_expire(bfqd, bfqq); /* @@ -2779,7 +2902,7 @@ static int bfq_dispatch_requests(struct request_queue *q, int force) return bfq_forced_dispatch(bfqd); bfqq = bfq_select_queue(bfqd); - if (bfqq == NULL) + if (!bfqq) return 0; if (bfq_class_idle(bfqq)) @@ -2819,6 +2942,9 @@ static int bfq_dispatch_requests(struct request_queue *q, int force) static void bfq_put_queue(struct bfq_queue *bfqq) { struct bfq_data *bfqd = bfqq->bfqd; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + struct bfq_group *bfqg = bfqq_group(bfqq); +#endif BUG_ON(atomic_read(&bfqq->ref) <= 0); @@ -2827,9 +2953,9 @@ static void bfq_put_queue(struct bfq_queue *bfqq) if (!atomic_dec_and_test(&bfqq->ref)) return; - BUG_ON(rb_first(&bfqq->sort_list) != NULL); + BUG_ON(rb_first(&bfqq->sort_list)); BUG_ON(bfqq->allocated[READ] + bfqq->allocated[WRITE] != 0); - BUG_ON(bfqq->entity.tree != NULL); + BUG_ON(bfqq->entity.tree); BUG_ON(bfq_bfqq_busy(bfqq)); BUG_ON(bfqd->in_service_queue == bfqq); @@ -2847,6 +2973,9 @@ static void bfq_put_queue(struct bfq_queue *bfqq) bfq_log_bfqq(bfqd, bfqq, "put_queue: %p freed", bfqq); kmem_cache_free(bfq_pool, bfqq); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_put(bfqg); +#endif } static void bfq_put_cooperator(struct bfq_queue *bfqq) @@ -2883,7 +3012,7 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_put_queue(bfqq); } -static inline void bfq_init_icq(struct io_cq *icq) +static void bfq_init_icq(struct io_cq *icq) { struct bfq_io_cq *bic = icq_to_bic(icq); @@ -2950,40 +3079,38 @@ static void bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *b /* * No prio set, inherit CPU scheduling settings. */ - bfqq->entity.new_ioprio = task_nice_ioprio(tsk); - bfqq->entity.new_ioprio_class = task_nice_ioclass(tsk); + bfqq->new_ioprio = task_nice_ioprio(tsk); + bfqq->new_ioprio_class = task_nice_ioclass(tsk); break; case IOPRIO_CLASS_RT: - bfqq->entity.new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); - bfqq->entity.new_ioprio_class = IOPRIO_CLASS_RT; + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_RT; break; case IOPRIO_CLASS_BE: - bfqq->entity.new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); - bfqq->entity.new_ioprio_class = IOPRIO_CLASS_BE; + bfqq->new_ioprio = IOPRIO_PRIO_DATA(bic->ioprio); + bfqq->new_ioprio_class = IOPRIO_CLASS_BE; break; case IOPRIO_CLASS_IDLE: - bfqq->entity.new_ioprio_class = IOPRIO_CLASS_IDLE; - bfqq->entity.new_ioprio = 7; + bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE; + bfqq->new_ioprio = 7; bfq_clear_bfqq_idle_window(bfqq); break; } - if (bfqq->entity.new_ioprio < 0 || - bfqq->entity.new_ioprio >= IOPRIO_BE_NR) { + if (bfqq->new_ioprio < 0 || bfqq->new_ioprio >= IOPRIO_BE_NR) { printk(KERN_CRIT "bfq_set_next_ioprio_data: new_ioprio %d\n", - bfqq->entity.new_ioprio); + bfqq->new_ioprio); BUG(); } - bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->entity.new_ioprio); - bfqq->entity.ioprio_changed = 1; + bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio); + bfqq->entity.prio_changed = 1; } -static void bfq_check_ioprio_change(struct bfq_io_cq *bic) +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) { struct bfq_data *bfqd; struct bfq_queue *bfqq, *new_bfqq; - struct bfq_group *bfqg; unsigned long uninitialized_var(flags); int ioprio = bic->icq.ioc->ioprio; @@ -2993,18 +3120,16 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic) * This condition may trigger on a newly created bic, be sure to * drop the lock before returning. */ - if (unlikely(bfqd == NULL) || likely(bic->ioprio == ioprio)) + if (unlikely(!bfqd) || likely(bic->ioprio == ioprio)) goto out; bic->ioprio = ioprio; bfqq = bic->bfqq[BLK_RW_ASYNC]; - if (bfqq != NULL) { - bfqg = container_of(bfqq->entity.sched_data, struct bfq_group, - sched_data); - new_bfqq = bfq_get_queue(bfqd, bfqg, BLK_RW_ASYNC, bic, + if (bfqq) { + new_bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic, GFP_ATOMIC); - if (new_bfqq != NULL) { + if (new_bfqq) { bic->bfqq[BLK_RW_ASYNC] = new_bfqq; bfq_log_bfqq(bfqd, bfqq, "check_ioprio_change: bfqq %p %d", @@ -3014,7 +3139,7 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic) } bfqq = bic->bfqq[BLK_RW_SYNC]; - if (bfqq != NULL) + if (bfqq) bfq_set_next_ioprio_data(bfqq, bic); out: @@ -3038,7 +3163,8 @@ static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (!bfq_class_idle(bfqq)) bfq_mark_bfqq_idle_window(bfqq); bfq_mark_bfqq_sync(bfqq); - } + } else + bfq_clear_bfqq_sync(bfqq); bfq_mark_bfqq_IO_bound(bfqq); /* Tentative initial value to trade off between thr and lat */ @@ -3055,14 +3181,19 @@ static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, } static struct bfq_queue *bfq_find_alloc_queue(struct bfq_data *bfqd, - struct bfq_group *bfqg, - int is_sync, + struct bio *bio, int is_sync, struct bfq_io_cq *bic, gfp_t gfp_mask) { + struct bfq_group *bfqg; struct bfq_queue *bfqq, *new_bfqq = NULL; + struct blkcg *blkcg; retry: + rcu_read_lock(); + + blkcg = bio_blkcg(bio); + bfqg = bfq_find_alloc_group(bfqd, blkcg); /* bic always exists here */ bfqq = bic_to_bfqq(bic, is_sync); @@ -3070,18 +3201,19 @@ retry: * Always try a new alloc if we fall back to the OOM bfqq * originally, since it should just be a temporary situation. */ - if (bfqq == NULL || bfqq == &bfqd->oom_bfqq) { + if (!bfqq || bfqq == &bfqd->oom_bfqq) { bfqq = NULL; - if (new_bfqq != NULL) { + if (new_bfqq) { bfqq = new_bfqq; new_bfqq = NULL; } else if (gfp_mask & __GFP_WAIT) { + rcu_read_unlock(); spin_unlock_irq(bfqd->queue->queue_lock); new_bfqq = kmem_cache_alloc_node(bfq_pool, gfp_mask | __GFP_ZERO, bfqd->queue->node); spin_lock_irq(bfqd->queue->queue_lock); - if (new_bfqq != NULL) + if (new_bfqq) goto retry; } else { bfqq = kmem_cache_alloc_node(bfq_pool, @@ -3089,7 +3221,7 @@ retry: bfqd->queue->node); } - if (bfqq != NULL) { + if (bfqq) { bfq_init_bfqq(bfqd, bfqq, bic, current->pid, is_sync); bfq_init_entity(&bfqq->entity, bfqg); @@ -3100,9 +3232,11 @@ retry: } } - if (new_bfqq != NULL) + if (new_bfqq) kmem_cache_free(bfq_pool, new_bfqq); + rcu_read_unlock(); + return bfqq; } @@ -3126,7 +3260,7 @@ static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd, } static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, - struct bfq_group *bfqg, int is_sync, + struct bio *bio, int is_sync, struct bfq_io_cq *bic, gfp_t gfp_mask) { const int ioprio = IOPRIO_PRIO_DATA(bic->ioprio); @@ -3135,19 +3269,26 @@ static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, struct bfq_queue *bfqq = NULL; if (!is_sync) { + struct blkcg *blkcg; + struct bfq_group *bfqg; + + rcu_read_lock(); + blkcg = bio_blkcg(bio); + rcu_read_unlock(); + bfqg = bfq_find_alloc_group(bfqd, blkcg); async_bfqq = bfq_async_queue_prio(bfqd, bfqg, ioprio_class, ioprio); bfqq = *async_bfqq; } - if (bfqq == NULL) - bfqq = bfq_find_alloc_queue(bfqd, bfqg, is_sync, bic, gfp_mask); + if (!bfqq) + bfqq = bfq_find_alloc_queue(bfqd, bio, is_sync, bic, gfp_mask); /* * Pin the queue now that it's allocated, scheduler exit will * prune it. */ - if (!is_sync && *async_bfqq == NULL) { + if (!is_sync && !(*async_bfqq)) { atomic_inc(&bfqq->ref); bfq_log_bfqq(bfqd, bfqq, "get_queue, bfqq not in async: %p, %d", bfqq, atomic_read(&bfqq->ref)); @@ -3280,9 +3421,9 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, bfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq); if (bfqq == bfqd->in_service_queue && bfq_bfqq_wait_request(bfqq)) { - int small_req = bfqq->queued[rq_is_sync(rq)] == 1 && - blk_rq_sectors(rq) < 32; - int budget_timeout = bfq_bfqq_budget_timeout(bfqq); + bool small_req = bfqq->queued[rq_is_sync(rq)] == 1 && + blk_rq_sectors(rq) < 32; + bool budget_timeout = bfq_bfqq_budget_timeout(bfqq); /* * There is just this request queued: if the request @@ -3309,6 +3450,9 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, */ bfq_clear_bfqq_wait_request(bfqq); del_timer(&bfqd->idle_slice_timer); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_idle_time(bfqq_group(bfqq)); +#endif /* * The queue is not empty, because a new request just @@ -3318,7 +3462,8 @@ static void bfq_rq_enqueued(struct bfq_data *bfqd, struct bfq_queue *bfqq, * See [1] for more details. */ if (budget_timeout) - bfq_bfqq_expire(bfqd, bfqq, 0, BFQ_BFQQ_BUDGET_TIMEOUT); + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); /* * Let the request rip immediately, or let a new queue be @@ -3342,7 +3487,7 @@ static void bfq_insert_request(struct request_queue *q, struct request *rq) */ if (!in_interrupt()) { new_bfqq = bfq_setup_cooperator(bfqd, bfqq, rq, true); - if (new_bfqq != NULL) { + if (new_bfqq) { if (bic_to_bfqq(RQ_BIC(rq), 1) != bfqq) new_bfqq = bic_to_bfqq(RQ_BIC(rq), 1); /* @@ -3370,7 +3515,7 @@ static void bfq_insert_request(struct request_queue *q, struct request *rq) * from assigning it a full weight-raising period. See the detailed * comments about this field in bfq_init_icq(). */ - if (bfqq->bic != NULL) + if (bfqq->bic) bfqq->bic->wr_time_left = 0; rq->fifo_time = jiffies + bfqd->bfq_fifo_expire[rq_is_sync(rq)]; list_add_tail(&rq->queuelist, &bfqq->fifo); @@ -3418,6 +3563,11 @@ static void bfq_completed_request(struct request_queue *q, struct request *rq) BUG_ON(!bfqq->dispatched); bfqd->rq_in_driver--; bfqq->dispatched--; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_completion(bfqq_group(bfqq), + rq_start_time_ns(rq), + rq_io_start_time_ns(rq), rq->cmd_flags); +#endif if (!bfqq->dispatched && !bfq_bfqq_busy(bfqq)) { bfq_weights_tree_remove(bfqd, &bfqq->entity, @@ -3462,11 +3612,12 @@ static void bfq_completed_request(struct request_queue *q, struct request *rq) bfq_arm_slice_timer(bfqd); goto out; } else if (bfq_may_expire_for_budg_timeout(bfqq)) - bfq_bfqq_expire(bfqd, bfqq, 0, BFQ_BFQQ_BUDGET_TIMEOUT); + bfq_bfqq_expire(bfqd, bfqq, false, + BFQ_BFQQ_BUDGET_TIMEOUT); else if (RB_EMPTY_ROOT(&bfqq->sort_list) && (bfqq->dispatched == 0 || - !bfq_bfqq_must_not_expire(bfqq))) - bfq_bfqq_expire(bfqd, bfqq, 0, + !bfq_bfqq_may_idle(bfqq))) + bfq_bfqq_expire(bfqd, bfqq, false, BFQ_BFQQ_NO_MORE_REQUESTS); } @@ -3477,7 +3628,7 @@ out: return; } -static inline int __bfq_may_queue(struct bfq_queue *bfqq) +static int __bfq_may_queue(struct bfq_queue *bfqq) { if (bfq_bfqq_wait_request(bfqq) && bfq_bfqq_must_alloc(bfqq)) { bfq_clear_bfqq_must_alloc(bfqq); @@ -3501,11 +3652,11 @@ static int bfq_may_queue(struct request_queue *q, int rw) * 'may queue' if that fails. */ bic = bfq_bic_lookup(bfqd, tsk->io_context); - if (bic == NULL) + if (!bic) return ELV_MQUEUE_MAY; bfqq = bic_to_bfqq(bic, rw_is_sync(rw)); - if (bfqq != NULL) + if (bfqq) return __bfq_may_queue(bfqq); return ELV_MQUEUE_MAY; @@ -3518,7 +3669,7 @@ static void bfq_put_request(struct request *rq) { struct bfq_queue *bfqq = RQ_BFQQ(rq); - if (bfqq != NULL) { + if (bfqq) { const int rw = rq_data_dir(rq); BUG_ON(!bfqq->allocated[rw]); @@ -3570,25 +3721,24 @@ static int bfq_set_request(struct request_queue *q, struct request *rq, const int rw = rq_data_dir(rq); const int is_sync = rq_is_sync(rq); struct bfq_queue *bfqq; - struct bfq_group *bfqg; unsigned long flags; bool split = false; might_sleep_if(gfp_mask & __GFP_WAIT); - bfq_check_ioprio_change(bic); + bfq_check_ioprio_change(bic, bio); spin_lock_irqsave(q->queue_lock, flags); - if (bic == NULL) + if (!bic) goto queue_fail; - bfqg = bfq_bic_update_cgroup(bic); + bfq_bic_update_cgroup(bic, bio); new_queue: bfqq = bic_to_bfqq(bic, is_sync); - if (bfqq == NULL || bfqq == &bfqd->oom_bfqq) { - bfqq = bfq_get_queue(bfqd, bfqg, is_sync, bic, gfp_mask); + if (!bfqq || bfqq == &bfqd->oom_bfqq) { + bfqq = bfq_get_queue(bfqd, bio, is_sync, bic, gfp_mask); bic_set_bfqq(bic, bfqq, is_sync); if (split && is_sync) { if ((bic->was_in_burst_list && bfqd->large_burst) || @@ -3684,7 +3834,7 @@ static void bfq_idle_slice_timer(unsigned long data) * the in-service queue. This can hardly happen, but in the worst * case we just expire a queue too early. */ - if (bfqq != NULL) { + if (bfqq) { bfq_log_bfqq(bfqd, bfqq, "slice_timer expired"); if (bfq_bfqq_budget_timeout(bfqq)) /* @@ -3704,7 +3854,7 @@ static void bfq_idle_slice_timer(unsigned long data) else goto schedule_dispatch; - bfq_bfqq_expire(bfqd, bfqq, 1, reason); + bfq_bfqq_expire(bfqd, bfqq, true, reason); } schedule_dispatch: @@ -3719,14 +3869,14 @@ static void bfq_shutdown_timer_wq(struct bfq_data *bfqd) cancel_work_sync(&bfqd->unplug_work); } -static inline void __bfq_put_async_bfqq(struct bfq_data *bfqd, +static void __bfq_put_async_bfqq(struct bfq_data *bfqd, struct bfq_queue **bfqq_ptr) { struct bfq_group *root_group = bfqd->root_group; struct bfq_queue *bfqq = *bfqq_ptr; bfq_log(bfqd, "put_async_bfqq: %p", bfqq); - if (bfqq != NULL) { + if (bfqq) { bfq_bfqq_move(bfqd, bfqq, &bfqq->entity, root_group); bfq_log_bfqq(bfqd, bfqq, "put_async_bfqq: putting %p, %d", bfqq, atomic_read(&bfqq->ref)); @@ -3762,7 +3912,7 @@ static void bfq_exit_queue(struct elevator_queue *e) spin_lock_irq(q->queue_lock); - BUG_ON(bfqd->in_service_queue != NULL); + BUG_ON(bfqd->in_service_queue); list_for_each_entry_safe(bfqq, n, &bfqd->idle_list, bfqq_list) bfq_deactivate_bfqq(bfqd, bfqq, 0); @@ -3775,22 +3925,39 @@ static void bfq_exit_queue(struct elevator_queue *e) BUG_ON(timer_pending(&bfqd->idle_slice_timer)); - bfq_free_root_group(bfqd); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + blkcg_deactivate_policy(q, &blkcg_policy_bfq); +#endif + kfree(bfqd); } +static void bfq_init_root_group(struct bfq_group *root_group, + struct bfq_data *bfqd) +{ + int i; + +#ifdef CONFIG_BFQ_GROUP_IOSCHED + root_group->entity.parent = NULL; + root_group->my_entity = NULL; + root_group->bfqd = bfqd; +#endif + root_group->rq_pos_tree = RB_ROOT; + for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) + root_group->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT; +} + static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) { - struct bfq_group *bfqg; struct bfq_data *bfqd; struct elevator_queue *eq; eq = elevator_alloc(q, e); - if (eq == NULL) + if (!eq) return -ENOMEM; bfqd = kzalloc_node(sizeof(*bfqd), GFP_KERNEL, q->node); - if (bfqd == NULL) { + if (!bfqd) { kobject_put(&eq->kobj); return -ENOMEM; } @@ -3803,16 +3970,16 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) */ bfq_init_bfqq(bfqd, &bfqd->oom_bfqq, NULL, 1, 0); atomic_inc(&bfqd->oom_bfqq.ref); - bfqd->oom_bfqq.entity.new_ioprio = BFQ_DEFAULT_QUEUE_IOPRIO; - bfqd->oom_bfqq.entity.new_ioprio_class = IOPRIO_CLASS_BE; + bfqd->oom_bfqq.new_ioprio = BFQ_DEFAULT_QUEUE_IOPRIO; + bfqd->oom_bfqq.new_ioprio_class = IOPRIO_CLASS_BE; bfqd->oom_bfqq.entity.new_weight = - bfq_ioprio_to_weight(bfqd->oom_bfqq.entity.new_ioprio); + bfq_ioprio_to_weight(bfqd->oom_bfqq.new_ioprio); /* * Trigger weight initialization, according to ioprio, at the * oom_bfqq's first activation. The oom_bfqq's ioprio and ioprio * class won't be changed any more. */ - bfqd->oom_bfqq.entity.ioprio_changed = 1; + bfqd->oom_bfqq.entity.prio_changed = 1; bfqd->queue = q; @@ -3820,16 +3987,12 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) q->elevator = eq; spin_unlock_irq(q->queue_lock); - bfqg = bfq_alloc_root_group(bfqd, q->node); - if (bfqg == NULL) { - kfree(bfqd); - kobject_put(&eq->kobj); - return -ENOMEM; - } - - bfqd->root_group = bfqg; + bfqd->root_group = bfq_create_group_hierarchy(bfqd, q->node); + if (!bfqd->root_group) + goto out_free; + bfq_init_root_group(bfqd->root_group, bfqd); bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group); -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED bfqd->active_numerous_groups = 0; #endif @@ -3837,7 +4000,6 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) bfqd->idle_slice_timer.function = bfq_idle_slice_timer; bfqd->idle_slice_timer.data = (unsigned long)bfqd; - bfqd->rq_pos_tree = RB_ROOT; bfqd->queue_weights_tree = RB_ROOT; bfqd->group_weights_tree = RB_ROOT; @@ -3895,18 +4057,23 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) bfqd->device_speed = BFQ_BFQD_FAST; return 0; + +out_free: + kfree(bfqd); + kobject_put(&eq->kobj); + return -ENOMEM; } static void bfq_slab_kill(void) { - if (bfq_pool != NULL) + if (bfq_pool) kmem_cache_destroy(bfq_pool); } static int __init bfq_slab_setup(void) { bfq_pool = KMEM_CACHE(bfq_queue, 0); - if (bfq_pool == NULL) + if (!bfq_pool) return -ENOMEM; return 0; } @@ -4051,7 +4218,7 @@ static ssize_t bfq_weights_store(struct elevator_queue *e, return count; } -static inline unsigned long bfq_estimated_max_budget(struct bfq_data *bfqd) +static unsigned long bfq_estimated_max_budget(struct bfq_data *bfqd) { u64 timeout = jiffies_to_msecs(bfqd->bfq_timeout[BLK_RW_SYNC]); @@ -4145,6 +4312,9 @@ static struct elevator_type iosched_bfq = { .elevator_merge_fn = bfq_merge, .elevator_merged_fn = bfq_merged_request, .elevator_merge_req_fn = bfq_merged_requests, +#ifdef CONFIG_BFQ_GROUP_IOSCHED + .elevator_bio_merged_fn = bfq_bio_merged, +#endif .elevator_allow_merge_fn = bfq_allow_merge, .elevator_dispatch_fn = bfq_dispatch_requests, .elevator_add_req_fn = bfq_insert_request, @@ -4170,6 +4340,8 @@ static struct elevator_type iosched_bfq = { static int __init bfq_init(void) { + int ret; + /* * Can be 0 on HZ < 1000 setups. */ @@ -4179,8 +4351,15 @@ static int __init bfq_init(void) if (bfq_timeout_async == 0) bfq_timeout_async = 1; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + ret = blkcg_policy_register(&blkcg_policy_bfq); + if (ret) + return ret; +#endif + + ret = -ENOMEM; if (bfq_slab_setup()) - return -ENOMEM; + goto err_pol_unreg; /* * Times to load large popular applications for the typical systems @@ -4199,15 +4378,27 @@ static int __init bfq_init(void) device_speed_thresh[0] = (R_fast[0] + R_slow[0]) / 2; device_speed_thresh[1] = (R_fast[1] + R_slow[1]) / 2; - elv_register(&iosched_bfq); - pr_info("BFQ I/O-scheduler: v7r8"); + ret = elv_register(&iosched_bfq); + if (ret) + goto err_pol_unreg; + + pr_info("BFQ I/O-scheduler: v7r9"); return 0; + +err_pol_unreg: +#ifdef CONFIG_BFQ_GROUP_IOSCHED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif + return ret; } static void __exit bfq_exit(void) { elv_unregister(&iosched_bfq); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + blkcg_policy_unregister(&blkcg_policy_bfq); +#endif bfq_slab_kill(); } diff --git a/block/bfq-sched.c b/block/bfq-sched.c index d0890c6d4..9328a1f09 100644 --- a/block/bfq-sched.c +++ b/block/bfq-sched.c @@ -10,24 +10,27 @@ * Copyright (C) 2010 Paolo Valente <paolo.valente@unimore.it> */ -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED #define for_each_entity(entity) \ - for (; entity != NULL; entity = entity->parent) + for (; entity ; entity = entity->parent) #define for_each_entity_safe(entity, parent) \ for (; entity && ({ parent = entity->parent; 1; }); entity = parent) + static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, int extract, struct bfq_data *bfqd); -static inline void bfq_update_budget(struct bfq_entity *next_in_service) +static struct bfq_group *bfqq_group(struct bfq_queue *bfqq); + +static void bfq_update_budget(struct bfq_entity *next_in_service) { struct bfq_entity *bfqg_entity; struct bfq_group *bfqg; struct bfq_sched_data *group_sd; - BUG_ON(next_in_service == NULL); + BUG_ON(!next_in_service); group_sd = next_in_service->sched_data; @@ -38,7 +41,7 @@ static inline void bfq_update_budget(struct bfq_entity *next_in_service) * as it must never become an in-service entity. */ bfqg_entity = bfqg->my_entity; - if (bfqg_entity != NULL) + if (bfqg_entity) bfqg_entity->budget = next_in_service->budget; } @@ -46,7 +49,7 @@ static int bfq_update_next_in_service(struct bfq_sched_data *sd) { struct bfq_entity *next_in_service; - if (sd->in_service_entity != NULL) + if (sd->in_service_entity) /* will update/requeue at the end of service */ return 0; @@ -60,35 +63,35 @@ static int bfq_update_next_in_service(struct bfq_sched_data *sd) next_in_service = bfq_lookup_next_entity(sd, 0, NULL); sd->next_in_service = next_in_service; - if (next_in_service != NULL) + if (next_in_service) bfq_update_budget(next_in_service); return 1; } -static inline void bfq_check_next_in_service(struct bfq_sched_data *sd, - struct bfq_entity *entity) +static void bfq_check_next_in_service(struct bfq_sched_data *sd, + struct bfq_entity *entity) { BUG_ON(sd->next_in_service != entity); } #else #define for_each_entity(entity) \ - for (; entity != NULL; entity = NULL) + for (; entity ; entity = NULL) #define for_each_entity_safe(entity, parent) \ - for (parent = NULL; entity != NULL; entity = parent) + for (parent = NULL; entity ; entity = parent) -static inline int bfq_update_next_in_service(struct bfq_sched_data *sd) +static int bfq_update_next_in_service(struct bfq_sched_data *sd) { return 0; } -static inline void bfq_check_next_in_service(struct bfq_sched_data *sd, - struct bfq_entity *entity) +static void bfq_check_next_in_service(struct bfq_sched_data *sd, + struct bfq_entity *entity) { } -static inline void bfq_update_budget(struct bfq_entity *next_in_service) +static void bfq_update_budget(struct bfq_entity *next_in_service) { } #endif @@ -109,18 +112,18 @@ static inline void bfq_update_budget(struct bfq_entity *next_in_service) * * Return @a > @b, dealing with wrapping correctly. */ -static inline int bfq_gt(u64 a, u64 b) +static int bfq_gt(u64 a, u64 b) { return (s64)(a - b) > 0; } -static inline struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) +static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) { struct bfq_queue *bfqq = NULL; - BUG_ON(entity == NULL); + BUG_ON(!entity); - if (entity->my_sched_data == NULL) + if (!entity->my_sched_data) bfqq = container_of(entity, struct bfq_queue, entity); return bfqq; @@ -132,8 +135,7 @@ static inline struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity) * @service: amount of service. * @weight: scale factor (weight of an entity or weight sum). */ -static inline u64 bfq_delta(unsigned long service, - unsigned long weight) +static u64 bfq_delta(unsigned long service, unsigned long weight) { u64 d = (u64)service << WFQ_SERVICE_SHIFT; @@ -146,8 +148,7 @@ static inline u64 bfq_delta(unsigned long service, * @entity: the entity to act upon. * @service: the service to be charged to the entity. */ -static inline void bfq_calc_finish(struct bfq_entity *entity, - unsigned long service) +static void bfq_calc_finish(struct bfq_entity *entity, unsigned long service) { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); @@ -156,7 +157,7 @@ static inline void bfq_calc_finish(struct bfq_entity *entity, entity->finish = entity->start + bfq_delta(service, entity->weight); - if (bfqq != NULL) { + if (bfqq) { bfq_log_bfqq(bfqq->bfqd, bfqq, "calc_finish: serv %lu, w %d", service, entity->weight); @@ -176,11 +177,11 @@ static inline void bfq_calc_finish(struct bfq_entity *entity, * conversion mechanism because, e.g., in the tree walking functions, * the check for a %NULL value would be redundant. */ -static inline struct bfq_entity *bfq_entity_of(struct rb_node *node) +static struct bfq_entity *bfq_entity_of(struct rb_node *node) { struct bfq_entity *entity = NULL; - if (node != NULL) + if (node) entity = rb_entry(node, struct bfq_entity, rb_node); return entity; @@ -191,8 +192,7 @@ static inline struct bfq_entity *bfq_entity_of(struct rb_node *node) * @root: the tree root. * @entity: the entity to remove. */ -static inline void bfq_extract(struct rb_root *root, - struct bfq_entity *entity) +static void bfq_extract(struct rb_root *root, struct bfq_entity *entity) { BUG_ON(entity->tree != root); @@ -225,7 +225,7 @@ static void bfq_idle_extract(struct bfq_service_tree *st, bfq_extract(&st->idle, entity); - if (bfqq != NULL) + if (bfqq) list_del(&bfqq->bfqq_list); } @@ -243,9 +243,9 @@ static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) struct rb_node **node = &root->rb_node; struct rb_node *parent = NULL; - BUG_ON(entity->tree != NULL); + BUG_ON(entity->tree); - while (*node != NULL) { + while (*node) { parent = *node; entry = rb_entry(parent, struct bfq_entity, rb_node); @@ -271,12 +271,11 @@ static void bfq_insert(struct rb_root *root, struct bfq_entity *entity) * that the subtree rooted at @node (which may be its left or its right * child) has a valid min_start value. */ -static inline void bfq_update_min(struct bfq_entity *entity, - struct rb_node *node) +static void bfq_update_min(struct bfq_entity *entity, struct rb_node *node) { struct bfq_entity *child; - if (node != NULL) { + if (node) { child = rb_entry(node, struct bfq_entity, rb_node); if (bfq_gt(entity->min_start, child->min_start)) entity->min_start = child->min_start; @@ -291,7 +290,7 @@ static inline void bfq_update_min(struct bfq_entity *entity, * this function updates its min_start value. The left and right subtrees * are assumed to hold a correct min_start value. */ -static inline void bfq_update_active_node(struct rb_node *node) +static void bfq_update_active_node(struct rb_node *node) { struct bfq_entity *entity = rb_entry(node, struct bfq_entity, rb_node); @@ -318,12 +317,12 @@ up: bfq_update_active_node(node); parent = rb_parent(node); - if (parent == NULL) + if (!parent) return; - if (node == parent->rb_left && parent->rb_right != NULL) + if (node == parent->rb_left && parent->rb_right) bfq_update_active_node(parent->rb_right); - else if (parent->rb_left != NULL) + else if (parent->rb_left) bfq_update_active_node(parent->rb_left); node = parent; @@ -355,7 +354,7 @@ static void bfq_active_insert(struct bfq_service_tree *st, { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); struct rb_node *node = &entity->rb_node; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED struct bfq_sched_data *sd = NULL; struct bfq_group *bfqg = NULL; struct bfq_data *bfqd = NULL; @@ -363,22 +362,22 @@ static void bfq_active_insert(struct bfq_service_tree *st, bfq_insert(&st->active, entity); - if (node->rb_left != NULL) + if (node->rb_left) node = node->rb_left; - else if (node->rb_right != NULL) + else if (node->rb_right) node = node->rb_right; bfq_update_active_tree(node); -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED sd = entity->sched_data; bfqg = container_of(sd, struct bfq_group, sched_data); BUG_ON(!bfqg); bfqd = (struct bfq_data *)bfqg->bfqd; #endif - if (bfqq != NULL) + if (bfqq) list_add(&bfqq->bfqq_list, &bfqq->bfqd->active_list); -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED else { /* bfq_group */ BUG_ON(!bfqd); bfq_weights_tree_add(bfqd, entity, &bfqd->group_weights_tree); @@ -397,31 +396,32 @@ static void bfq_active_insert(struct bfq_service_tree *st, * bfq_ioprio_to_weight - calc a weight from an ioprio. * @ioprio: the ioprio value to convert. */ -static inline unsigned short bfq_ioprio_to_weight(int ioprio) +static unsigned short bfq_ioprio_to_weight(int ioprio) { BUG_ON(ioprio < 0 || ioprio >= IOPRIO_BE_NR); - return IOPRIO_BE_NR - ioprio; + return IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - ioprio; } /** * bfq_weight_to_ioprio - calc an ioprio from a weight. * @weight: the weight value to convert. * - * To preserve as mush as possible the old only-ioprio user interface, + * To preserve as much as possible the old only-ioprio user interface, * 0 is used as an escape ioprio value for weights (numerically) equal or - * larger than IOPRIO_BE_NR + * larger than IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF. */ -static inline unsigned short bfq_weight_to_ioprio(int weight) +static unsigned short bfq_weight_to_ioprio(int weight) { BUG_ON(weight < BFQ_MIN_WEIGHT || weight > BFQ_MAX_WEIGHT); - return IOPRIO_BE_NR - weight < 0 ? 0 : IOPRIO_BE_NR - weight; + return IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight < 0 ? + 0 : IOPRIO_BE_NR * BFQ_WEIGHT_CONVERSION_COEFF - weight; } -static inline void bfq_get_entity(struct bfq_entity *entity) +static void bfq_get_entity(struct bfq_entity *entity) { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); - if (bfqq != NULL) { + if (bfqq) { atomic_inc(&bfqq->ref); bfq_log_bfqq(bfqq->bfqd, bfqq, "get_entity: %p %d", bfqq, atomic_read(&bfqq->ref)); @@ -441,15 +441,15 @@ static struct rb_node *bfq_find_deepest(struct rb_node *node) { struct rb_node *deepest; - if (node->rb_right == NULL && node->rb_left == NULL) + if (!node->rb_right && !node->rb_left) deepest = rb_parent(node); - else if (node->rb_right == NULL) + else if (!node->rb_right) deepest = node->rb_left; - else if (node->rb_left == NULL) + else if (!node->rb_left) deepest = node->rb_right; else { deepest = rb_next(node); - if (deepest->rb_right != NULL) + if (deepest->rb_right) deepest = deepest->rb_right; else if (rb_parent(deepest) != node) deepest = rb_parent(deepest); @@ -468,7 +468,7 @@ static void bfq_active_extract(struct bfq_service_tree *st, { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); struct rb_node *node; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED struct bfq_sched_data *sd = NULL; struct bfq_group *bfqg = NULL; struct bfq_data *bfqd = NULL; @@ -477,18 +477,18 @@ static void bfq_active_extract(struct bfq_service_tree *st, node = bfq_find_deepest(&entity->rb_node); bfq_extract(&st->active, entity); - if (node != NULL) + if (node) bfq_update_active_tree(node); -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED sd = entity->sched_data; bfqg = container_of(sd, struct bfq_group, sched_data); BUG_ON(!bfqg); bfqd = (struct bfq_data *)bfqg->bfqd; #endif - if (bfqq != NULL) + if (bfqq) list_del(&bfqq->bfqq_list); -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED else { /* bfq_group */ BUG_ON(!bfqd); bfq_weights_tree_remove(bfqd, entity, @@ -519,14 +519,14 @@ static void bfq_idle_insert(struct bfq_service_tree *st, struct bfq_entity *first_idle = st->first_idle; struct bfq_entity *last_idle = st->last_idle; - if (first_idle == NULL || bfq_gt(first_idle->finish, entity->finish)) + if (!first_idle || bfq_gt(first_idle->finish, entity->finish)) st->first_idle = entity; - if (last_idle == NULL || bfq_gt(entity->finish, last_idle->finish)) + if (!last_idle || bfq_gt(entity->finish, last_idle->finish)) st->last_idle = entity; bfq_insert(&st->idle, entity); - if (bfqq != NULL) + if (bfqq) list_add(&bfqq->bfqq_list, &bfqq->bfqd->idle_list); } @@ -549,7 +549,7 @@ static void bfq_forget_entity(struct bfq_service_tree *st, entity->on_st = 0; st->wsum -= entity->weight; - if (bfqq != NULL) { + if (bfqq) { sd = entity->sched_data; bfq_log_bfqq(bfqq->bfqd, bfqq, "forget_entity: %p %d", bfqq, atomic_read(&bfqq->ref)); @@ -581,7 +581,7 @@ static void bfq_forget_idle(struct bfq_service_tree *st) struct bfq_entity *first_idle = st->first_idle; struct bfq_entity *last_idle = st->last_idle; - if (RB_EMPTY_ROOT(&st->active) && last_idle != NULL && + if (RB_EMPTY_ROOT(&st->active) && last_idle && !bfq_gt(last_idle->finish, st->vtime)) { /* * Forget the whole idle tree, increasing the vtime past @@ -590,7 +590,7 @@ static void bfq_forget_idle(struct bfq_service_tree *st) st->vtime = last_idle->finish; } - if (first_idle != NULL && !bfq_gt(first_idle->finish, st->vtime)) + if (first_idle && !bfq_gt(first_idle->finish, st->vtime)) bfq_put_idle_entity(st, first_idle); } @@ -600,19 +600,19 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, { struct bfq_service_tree *new_st = old_st; - if (entity->ioprio_changed) { + if (entity->prio_changed) { struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); unsigned short prev_weight, new_weight; struct bfq_data *bfqd = NULL; struct rb_root *root; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED struct bfq_sched_data *sd; struct bfq_group *bfqg; #endif - if (bfqq != NULL) + if (bfqq) bfqd = bfqq->bfqd; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED else { sd = entity->my_sched_data; bfqg = container_of(sd, struct bfq_group, sched_data); @@ -634,12 +634,14 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, BUG(); } entity->orig_weight = entity->new_weight; - entity->ioprio = - bfq_weight_to_ioprio(entity->orig_weight); + if (bfqq) + bfqq->ioprio = + bfq_weight_to_ioprio(entity->orig_weight); } - entity->ioprio_class = entity->new_ioprio_class; - entity->ioprio_changed = 0; + if (bfqq) + bfqq->ioprio_class = bfqq->new_ioprio_class; + entity->prio_changed = 0; /* * NOTE: here we may be changing the weight too early, @@ -652,7 +654,7 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, prev_weight = entity->weight; new_weight = entity->orig_weight * - (bfqq != NULL ? bfqq->wr_coeff : 1); + (bfqq ? bfqq->wr_coeff : 1); /* * If the weight of the entity changes, remove the entity * from its old weight counter (if there is a counter @@ -683,6 +685,10 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, return new_st; } +#ifdef CONFIG_BFQ_GROUP_IOSCHED +static void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg); +#endif + /** * bfq_bfqq_served - update the scheduler status after selection for * service. @@ -693,7 +699,7 @@ __bfq_entity_update_weight_prio(struct bfq_service_tree *old_st, * are synchronized every time a new bfqq is selected for service. By now, * we keep it to better check consistency. */ -static void bfq_bfqq_served(struct bfq_queue *bfqq, unsigned long served) +static void bfq_bfqq_served(struct bfq_queue *bfqq, int served) { struct bfq_entity *entity = &bfqq->entity; struct bfq_service_tree *st; @@ -708,7 +714,10 @@ static void bfq_bfqq_served(struct bfq_queue *bfqq, unsigned long served) st->vtime += bfq_delta(served, st->wsum); bfq_forget_idle(st); } - bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %lu secs", served); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_set_start_empty_time(bfqq_group(bfqq)); +#endif + bfq_log_bfqq(bfqq->bfqd, bfqq, "bfqq_served %d secs", served); } /** @@ -721,7 +730,7 @@ static void bfq_bfqq_served(struct bfq_queue *bfqq, unsigned long served) * budget. In this way we should obtain a sort of time-domain * fairness among all the seeky/slow queues. */ -static inline void bfq_bfqq_charge_full_budget(struct bfq_queue *bfqq) +static void bfq_bfqq_charge_full_budget(struct bfq_queue *bfqq) { struct bfq_entity *entity = &bfqq->entity; @@ -746,7 +755,7 @@ static void __bfq_activate_entity(struct bfq_entity *entity) struct bfq_service_tree *st = bfq_entity_service_tree(entity); if (entity == sd->in_service_entity) { - BUG_ON(entity->tree != NULL); + BUG_ON(entity->tree); /* * If we are requeueing the current entity we have * to take care of not charging to it service it has @@ -837,7 +846,7 @@ static int __bfq_deactivate_entity(struct bfq_entity *entity, int requeue) if (!entity->on_st) return 0; - BUG_ON(was_in_service && entity->tree != NULL); + BUG_ON(was_in_service && entity->tree); if (was_in_service) { bfq_calc_finish(entity, entity->service); @@ -846,7 +855,7 @@ static int __bfq_deactivate_entity(struct bfq_entity *entity, int requeue) bfq_active_extract(st, entity); else if (entity->tree == &st->idle) bfq_idle_extract(st, entity); - else if (entity->tree != NULL) + else if (entity->tree) BUG(); if (was_in_service || sd->next_in_service == entity) @@ -884,7 +893,7 @@ static void bfq_deactivate_entity(struct bfq_entity *entity, int requeue) */ break; - if (sd->next_in_service != NULL) + if (sd->next_in_service) /* * The parent entity is still backlogged and * the budgets on the path towards the root @@ -953,7 +962,7 @@ static struct bfq_entity *bfq_first_active_entity(struct bfq_service_tree *st) struct bfq_entity *entry, *first = NULL; struct rb_node *node = st->active.rb_node; - while (node != NULL) { + while (node) { entry = rb_entry(node, struct bfq_entity, rb_node); left: if (!bfq_gt(entry->start, st->vtime)) @@ -961,7 +970,7 @@ left: BUG_ON(bfq_gt(entry->min_start, st->vtime)); - if (node->rb_left != NULL) { + if (node->rb_left) { entry = rb_entry(node->rb_left, struct bfq_entity, rb_node); if (!bfq_gt(entry->min_start, st->vtime)) { @@ -969,12 +978,12 @@ left: goto left; } } - if (first != NULL) + if (first) break; node = node->rb_right; } - BUG_ON(first == NULL && !RB_EMPTY_ROOT(&st->active)); + BUG_ON(!first && !RB_EMPTY_ROOT(&st->active)); return first; } @@ -1030,13 +1039,13 @@ static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, struct bfq_entity *entity; int i = 0; - BUG_ON(sd->in_service_entity != NULL); + BUG_ON(sd->in_service_entity); - if (bfqd != NULL && + if (bfqd && jiffies - bfqd->bfq_class_idle_last_service > BFQ_CL_IDLE_TIMEOUT) { entity = __bfq_lookup_next_entity(st + BFQ_IOPRIO_CLASSES - 1, true); - if (entity != NULL) { + if (entity) { i = BFQ_IOPRIO_CLASSES - 1; bfqd->bfq_class_idle_last_service = jiffies; sd->next_in_service = entity; @@ -1044,7 +1053,7 @@ static struct bfq_entity *bfq_lookup_next_entity(struct bfq_sched_data *sd, } for (; i < BFQ_IOPRIO_CLASSES; i++) { entity = __bfq_lookup_next_entity(st + i, false); - if (entity != NULL) { + if (entity) { if (extract) { bfq_check_next_in_service(sd, entity); bfq_active_extract(st + i, entity); @@ -1067,27 +1076,27 @@ static struct bfq_queue *bfq_get_next_queue(struct bfq_data *bfqd) struct bfq_sched_data *sd; struct bfq_queue *bfqq; - BUG_ON(bfqd->in_service_queue != NULL); + BUG_ON(bfqd->in_service_queue); if (bfqd->busy_queues == 0) return NULL; sd = &bfqd->root_group->sched_data; - for (; sd != NULL; sd = entity->my_sched_data) { + for (; sd ; sd = entity->my_sched_data) { entity = bfq_lookup_next_entity(sd, 1, bfqd); - BUG_ON(entity == NULL); + BUG_ON(!entity); entity->service = 0; } bfqq = bfq_entity_to_bfqq(entity); - BUG_ON(bfqq == NULL); + BUG_ON(!bfqq); return bfqq; } static void __bfq_bfqd_reset_in_service(struct bfq_data *bfqd) { - if (bfqd->in_service_bic != NULL) { + if (bfqd->in_service_bic) { put_io_context(bfqd->in_service_bic->icq.ioc); bfqd->in_service_bic = NULL; } @@ -1114,6 +1123,10 @@ static void bfq_activate_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfq_activate_entity(entity); } +#ifdef CONFIG_BFQ_GROUP_IOSCHED +static void bfqg_stats_update_dequeue(struct bfq_group *bfqg); +#endif + /* * Called when the bfqq no longer has requests pending, remove it from * the service tree. @@ -1147,6 +1160,10 @@ static void bfq_del_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (bfqq->wr_coeff > 1) bfqd->wr_busy_queues--; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + bfqg_stats_update_dequeue(bfqq_group(bfqq)); +#endif + bfq_deactivate_bfqq(bfqd, bfqq, requeue); } diff --git a/block/bfq.h b/block/bfq.h index 96ffbf773..320c4389b 100644 --- a/block/bfq.h +++ b/block/bfq.h @@ -1,5 +1,5 @@ /* - * BFQ-v7r8 for 4.1.0: data structures and common functions prototypes. + * BFQ-v7r9 for 4.2.0: data structures and common functions prototypes. * * Based on ideas and code from CFQ: * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk> @@ -17,12 +17,14 @@ #include <linux/hrtimer.h> #include <linux/ioprio.h> #include <linux/rbtree.h> +#include <linux/blk-cgroup.h> #define BFQ_IOPRIO_CLASSES 3 #define BFQ_CL_IDLE_TIMEOUT (HZ/5) -#define BFQ_MIN_WEIGHT 1 -#define BFQ_MAX_WEIGHT 1000 +#define BFQ_MIN_WEIGHT 1 +#define BFQ_MAX_WEIGHT 1000 +#define BFQ_WEIGHT_CONVERSION_COEFF 10 #define BFQ_DEFAULT_QUEUE_IOPRIO 4 @@ -117,12 +119,8 @@ struct bfq_weight_counter { * @ioprio: the ioprio in use. * @new_weight: when a weight change is requested, the new weight value. * @orig_weight: original weight, used to implement weight boosting - * @new_ioprio: when an ioprio change is requested, the new ioprio value. - * @ioprio_class: the ioprio_class in use. - * @new_ioprio_class: when an ioprio_class change is requested, the new - * ioprio_class value. - * @ioprio_changed: flag, true when the user requested a weight, ioprio or - * ioprio_class change. + * @prio_changed: flag, true when the user requested a weight, ioprio or + * ioprio_class change. * * A bfq_entity is used to represent either a bfq_queue (leaf node in the * cgroup hierarchy) or a bfq_group into the upper level scheduler. Each @@ -134,7 +132,7 @@ struct bfq_weight_counter { * allow different weights on different devices, but this * functionality is not exported to userspace by now. Priorities and * weights are updated lazily, first storing the new values into the - * new_* fields, then setting the @ioprio_changed flag. As soon as + * new_* fields, then setting the @prio_changed flag. As soon as * there is a transition in the entity state that allows the priority * update to take place the effective and the requested priority * values are synchronized. @@ -161,7 +159,7 @@ struct bfq_entity { u64 min_start; - unsigned long service, budget; + int service, budget; unsigned short weight, new_weight; unsigned short orig_weight; @@ -170,10 +168,7 @@ struct bfq_entity { struct bfq_sched_data *my_sched_data; struct bfq_sched_data *sched_data; - unsigned short ioprio, new_ioprio; - unsigned short ioprio_class, new_ioprio_class; - - int ioprio_changed; + int prio_changed; }; struct bfq_group; @@ -182,10 +177,14 @@ struct bfq_group; * struct bfq_queue - leaf schedulable entity. * @ref: reference counter. * @bfqd: parent bfq_data. + * @new_ioprio: when an ioprio change is requested, the new ioprio value. + * @ioprio_class: the ioprio_class in use. + * @new_ioprio_class: when an ioprio_class change is requested, the new + * ioprio_class value. * @new_bfqq: shared bfq_queue if queue is cooperating with * one or more other queues. - * @pos_node: request-position tree member (see bfq_data's @rq_pos_tree). - * @pos_root: request-position tree root (see bfq_data's @rq_pos_tree). + * @pos_node: request-position tree member (see bfq_group's @rq_pos_tree). + * @pos_root: request-position tree root (see bfq_group's @rq_pos_tree). * @sort_list: sorted list of pending requests. * @next_rq: if fifo isn't expired, next request to serve. * @queued: nr of requests queued in @sort_list. @@ -239,6 +238,9 @@ struct bfq_queue { atomic_t ref; struct bfq_data *bfqd; + unsigned short ioprio, new_ioprio; + unsigned short ioprio_class, new_ioprio_class; + /* fields for cooperating queues handling */ struct bfq_queue *new_bfqq; struct rb_node pos_node; @@ -253,7 +255,7 @@ struct bfq_queue { struct bfq_entity entity; - unsigned long max_budget; + int max_budget; unsigned long budget_timeout; int dispatched; @@ -302,6 +304,8 @@ struct bfq_ttime { * @icq: associated io_cq structure * @bfqq: array of two process queues, the sync and the async * @ttime: associated @bfq_ttime struct + * @ioprio: per (request_queue, blkcg) ioprio. + * @blkcg_id: id of the blkcg the related io_cq belongs to. * @wr_time_left: snapshot of the time left before weight raising ends * for the sync queue associated to this process; this * snapshot is taken to remember this value while the weight @@ -329,6 +333,10 @@ struct bfq_io_cq { struct bfq_ttime ttime; int ioprio; +#ifdef CONFIG_BFQ_GROUP_IOSCHED + uint64_t blkcg_id; /* the current blkcg ID */ +#endif + unsigned int wr_time_left; bool saved_idle_window; bool saved_IO_bound; @@ -349,9 +357,6 @@ enum bfq_device_speed { * struct bfq_data - per device data structure. * @queue: request queue for the managed device. * @root_group: root bfq_group for the device. - * @rq_pos_tree: rbtree sorted by next_request position, used when - * determining if two or more queues have interleaving - * requests (see bfq_close_cooperator()). * @active_numerous_groups: number of bfq_groups containing more than one * active @bfq_entity. * @queue_weights_tree: rbtree of weight counters of @bfq_queues, sorted by @@ -485,9 +490,8 @@ struct bfq_data { struct request_queue *queue; struct bfq_group *root_group; - struct rb_root rq_pos_tree; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED int active_numerous_groups; #endif @@ -520,7 +524,7 @@ struct bfq_data { ktime_t last_idling_start; int peak_rate_samples; u64 peak_rate; - unsigned long bfq_max_budget; + int bfq_max_budget; struct hlist_head group_list; struct list_head active_list; @@ -532,8 +536,8 @@ struct bfq_data { unsigned int bfq_slice_idle; u64 bfq_class_idle_last_service; - unsigned int bfq_user_max_budget; - unsigned int bfq_max_budget_async_rq; + int bfq_user_max_budget; + int bfq_max_budget_async_rq; unsigned int bfq_timeout[2]; unsigned int bfq_coop_thresh; @@ -593,15 +597,15 @@ enum bfqq_state_flags { }; #define BFQ_BFQQ_FNS(name) \ -static inline void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ +static void bfq_mark_bfqq_##name(struct bfq_queue *bfqq) \ { \ (bfqq)->flags |= (1 << BFQ_BFQQ_FLAG_##name); \ } \ -static inline void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ +static void bfq_clear_bfqq_##name(struct bfq_queue *bfqq) \ { \ (bfqq)->flags &= ~(1 << BFQ_BFQQ_FLAG_##name); \ } \ -static inline int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ +static int bfq_bfqq_##name(const struct bfq_queue *bfqq) \ { \ return ((bfqq)->flags & (1 << BFQ_BFQQ_FLAG_##name)) != 0; \ } @@ -640,14 +644,64 @@ enum bfqq_expiration { BFQ_BFQQ_NO_MORE_REQUESTS, /* the queue has no more requests */ }; -#ifdef CONFIG_CGROUP_BFQIO +#ifdef CONFIG_BFQ_GROUP_IOSCHED + +struct bfqg_stats { + /* total bytes transferred */ + struct blkg_rwstat service_bytes; + /* total IOs serviced, post merge */ + struct blkg_rwstat serviced; + /* number of ios merged */ + struct blkg_rwstat merged; + /* total time spent on device in ns, may not be accurate w/ queueing */ + struct blkg_rwstat service_time; + /* total time spent waiting in scheduler queue in ns */ + struct blkg_rwstat wait_time; + /* number of IOs queued up */ + struct blkg_rwstat queued; + /* total sectors transferred */ + struct blkg_stat sectors; + /* total disk time and nr sectors dispatched by this group */ + struct blkg_stat time; + /* time not charged to this cgroup */ + struct blkg_stat unaccounted_time; + /* sum of number of ios queued across all samples */ + struct blkg_stat avg_queue_size_sum; + /* count of samples taken for average */ + struct blkg_stat avg_queue_size_samples; + /* how many times this group has been removed from service tree */ + struct blkg_stat dequeue; + /* total time spent waiting for it to be assigned a timeslice. */ + struct blkg_stat group_wait_time; + /* time spent idling for this blkcg_gq */ + struct blkg_stat idle_time; + /* total time with empty current active q with other requests queued */ + struct blkg_stat empty_time; + /* fields after this shouldn't be cleared on stat reset */ + uint64_t start_group_wait_time; + uint64_t start_idle_time; + uint64_t start_empty_time; + uint16_t flags; +}; + +/* + * struct bfq_group_data - per-blkcg storage for the blkio subsystem. + * + * @ps: @blkcg_policy_storage that this structure inherits + * @weight: weight of the bfq_group + */ +struct bfq_group_data { + /* must be the first member */ + struct blkcg_policy_data pd; + + unsigned short weight; +}; + /** * struct bfq_group - per (device, cgroup) data structure. * @entity: schedulable entity to insert into the parent group sched_data. * @sched_data: own sched_data, to contain child entities (they may be * both bfq_queues and bfq_groups). - * @group_node: node to be inserted into the bfqio_cgroup->group_data - * list of the containing cgroup's bfqio_cgroup. * @bfqd_node: node to be inserted into the @bfqd->group_list list * of the groups active on the same device; used for cleanup. * @bfqd: the bfq_data for the device this group acts upon. @@ -663,23 +717,26 @@ enum bfqq_expiration { * are groups with more than one active @bfq_entity * (see the comments to the function * bfq_bfqq_must_not_expire()). + * @rq_pos_tree: rbtree sorted by next_request position, used when + * determining if two or more queues have interleaving + * requests (see bfq_find_close_cooperator()). * * Each (device, cgroup) pair has its own bfq_group, i.e., for each cgroup * there is a set of bfq_groups, each one collecting the lower-level * entities belonging to the group that are acting on the same device. * * Locking works as follows: - * o @group_node is protected by the bfqio_cgroup lock, and is accessed - * via RCU from its readers. * o @bfqd is protected by the queue lock, RCU is used to access it * from the readers. * o All the other fields are protected by the @bfqd queue lock. */ struct bfq_group { + /* must be the first member */ + struct blkg_policy_data pd; + struct bfq_entity entity; struct bfq_sched_data sched_data; - struct hlist_node group_node; struct hlist_node bfqd_node; void *bfqd; @@ -690,44 +747,33 @@ struct bfq_group { struct bfq_entity *my_entity; int active_entities; -}; -/** - * struct bfqio_cgroup - bfq cgroup data structure. - * @css: subsystem state for bfq in the containing cgroup. - * @online: flag marked when the subsystem is inserted. - * @weight: cgroup weight. - * @ioprio: cgroup ioprio. - * @ioprio_class: cgroup ioprio_class. - * @lock: spinlock that protects @ioprio, @ioprio_class and @group_data. - * @group_data: list containing the bfq_group belonging to this cgroup. - * - * @group_data is accessed using RCU, with @lock protecting the updates, - * @ioprio and @ioprio_class are protected by @lock. - */ -struct bfqio_cgroup { - struct cgroup_subsys_state css; - bool online; - - unsigned short weight, ioprio, ioprio_class; + struct rb_root rq_pos_tree; - spinlock_t lock; - struct hlist_head group_data; + struct bfqg_stats stats; + struct bfqg_stats dead_stats; /* stats pushed from dead children */ }; + #else struct bfq_group { struct bfq_sched_data sched_data; struct bfq_queue *async_bfqq[2][IOPRIO_BE_NR]; struct bfq_queue *async_idle_bfqq; + + struct rb_root rq_pos_tree; }; #endif -static inline struct bfq_service_tree * +static struct bfq_queue *bfq_entity_to_bfqq(struct bfq_entity *entity); + +static struct bfq_service_tree * bfq_entity_service_tree(struct bfq_entity *entity) { struct bfq_sched_data *sched_data = entity->sched_data; - unsigned int idx = entity->ioprio_class - 1; + struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity); + unsigned int idx = bfqq ? bfqq->ioprio_class - 1 : + BFQ_DEFAULT_GRP_CLASS; BUG_ON(idx >= BFQ_IOPRIO_CLASSES); BUG_ON(sched_data == NULL); @@ -735,19 +781,18 @@ bfq_entity_service_tree(struct bfq_entity *entity) return sched_data->service_tree + idx; } -static inline struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, - bool is_sync) +static struct bfq_queue *bic_to_bfqq(struct bfq_io_cq *bic, bool is_sync) { return bic->bfqq[is_sync]; } -static inline void bic_set_bfqq(struct bfq_io_cq *bic, - struct bfq_queue *bfqq, bool is_sync) +static void bic_set_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq, + bool is_sync) { bic->bfqq[is_sync] = bfqq; } -static inline struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) +static struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) { return bic->icq.q->elevator->elevator_data; } @@ -766,8 +811,7 @@ static inline struct bfq_data *bic_to_bfqd(struct bfq_io_cq *bic) * the function returns NULL, with the queue unlocked, otherwise it * returns the dereferenced pointer, with the queue locked. */ -static inline struct bfq_data *bfq_get_bfqd_locked(void **ptr, - unsigned long *flags) +static struct bfq_data *bfq_get_bfqd_locked(void **ptr, unsigned long *flags) { struct bfq_data *bfqd; @@ -776,7 +820,9 @@ static inline struct bfq_data *bfq_get_bfqd_locked(void **ptr, if (bfqd != NULL) { spin_lock_irqsave(bfqd->queue->queue_lock, *flags); - if (*ptr == bfqd) + if (ptr == NULL) + printk(KERN_CRIT "get_bfqd_locked pointer NULL\n"); + else if (*ptr == bfqd) goto out; spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); } @@ -787,17 +833,37 @@ out: return bfqd; } -static inline void bfq_put_bfqd_unlock(struct bfq_data *bfqd, - unsigned long *flags) +static void bfq_put_bfqd_unlock(struct bfq_data *bfqd, unsigned long *flags) { spin_unlock_irqrestore(bfqd->queue->queue_lock, *flags); } -static void bfq_check_ioprio_change(struct bfq_io_cq *bic); +#ifdef CONFIG_BFQ_GROUP_IOSCHED + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + struct bfq_entity *group_entity = bfqq->entity.parent; + + if (!group_entity) + group_entity = &bfqq->bfqd->root_group->entity; + + return container_of(group_entity, struct bfq_group, entity); +} + +#else + +static struct bfq_group *bfq_bfqq_to_bfqg(struct bfq_queue *bfqq) +{ + return bfqq->bfqd->root_group; +} + +#endif + +static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio); static void bfq_put_queue(struct bfq_queue *bfqq); static void bfq_dispatch_insert(struct request_queue *q, struct request *rq); static struct bfq_queue *bfq_get_queue(struct bfq_data *bfqd, - struct bfq_group *bfqg, int is_sync, + struct bio *bio, int is_sync, struct bfq_io_cq *bic, gfp_t gfp_mask); static void bfq_end_wr_async_queues(struct bfq_data *bfqd, struct bfq_group *bfqg); |