// SPDX-License-Identifier: GPL-2.0-or-later
/*
* cgroups support for the BFQ I/O scheduler.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/cgroup.h>
#include <linux/ktime.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/sbitmap.h>
#include <linux/delay.h>
#include "elevator.h"
#include "bfq-iosched.h"
#ifdef CONFIG_BFQ_CGROUP_DEBUG
static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)
{
int ret;
ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
if (ret)
return ret;
atomic64_set(&stat->aux_cnt, 0);
return 0;
}
static void bfq_stat_exit(struct bfq_stat *stat)
{
percpu_counter_destroy(&stat->cpu_cnt);
}
/**
* bfq_stat_add - add a value to a bfq_stat
* @stat: target bfq_stat
* @val: value to add
*
* Add @val to @stat. The caller must ensure that IRQ on the same CPU
* don't re-enter this function for the same counter.
*/
static inline void bfq_stat_add(struct bfq_stat *stat, uint64_t val)
{
percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
}
/**
* bfq_stat_read - read the current value of a bfq_stat
* @stat: bfq_stat to read
*/
static inline uint64_t bfq_stat_read(struct bfq_stat *stat)
{
return percpu_counter_sum_positive(&stat->cpu_cnt);
}
/**
* bfq_stat_reset - reset a bfq_stat
* @stat: bfq_stat to reset
*/
static inline void bfq_stat_reset(struct bfq_stat *stat)
{
percpu_counter_set(&stat->cpu_cnt, 0);
atomic64_set(&stat->aux_cnt, 0);
}
/**
* bfq_stat_add_aux - add a bfq_stat into another's aux count
* @to: the destination bfq_stat
* @from: the source
*
* Add @from's count including the aux one to @to's aux count.
*/
static inline void bfq_stat_add_aux(struct bfq_stat *to,
struct bfq_stat *from)
{
atomic64_add(bfq_stat_read(from) + atomic64_read(&from->aux_cnt),
&to->aux_cnt);
}
/**
* blkg_prfill_stat - prfill callback for bfq_stat
* @sf: seq_file to print to
* @pd: policy private data of interest
* @off: offset to the bfq_stat in @pd
*
* prfill callback for printing a bfq_stat.
*/
static u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
return __blkg_prfill_u64(sf, pd, bfq_stat_read((void *)pd + off));
}
/* bfqg stats flags */
enum bfqg_stats_flags {
BFQG_stats_waiting = 0,
BFQG_stats_idling,
BFQG_stats_empty,
};
#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; \
} \
BFQG_FLAG_FNS(waiting)
BFQG_FLAG_FNS(idling)
BFQG_FLAG_FNS(empty)
#undef BFQG_FLAG_FNS
/* This should be called with the scheduler lock held. */
static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)
{
u64 now;
if (!bfqg_stats_waiting(stats))
return;
now = blk_time_get_ns();
if (now > stats->start_group_wait_time)
bfq_stat_add(&stats->group_wait_time,
now - stats->start_group_wait_time);
bfqg_stats_clear_waiting(stats);
}
/* This should be called with the scheduler lock held. */
static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
struct bfq_group *curr_bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (bfqg_stats_waiting(stats))
return;
if (bfqg == curr_bfqg)
return;
stats->start_group_wait_time = blk_time_get_ns();
bfqg_stats_mark_waiting(stats);
}
/* This should be called with the scheduler lock held. */
static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)
{
u64 now;
if (!bfqg_stats_empty(stats))
return;
now = blk_time_get_ns();
if (now > stats->start_empty_time)
bfq_stat_add(&stats->empty_time,
now - stats->start_empty_time);
bfqg_stats_clear_empty(stats);
}
void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
{
bfq_stat_add(&bfqg->stats.dequeue, 1);
}
void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (blkg_rwstat_total(&stats->queued))
return;
/*
* 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 (bfqg_stats_empty(stats))
return;
stats->start_empty_time = blk_time_get_ns();
bfqg_stats_mark_empty(stats);
}
void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (bfqg_stats_idling(stats)) {
u64 now = blk_time_get_ns();
if (now > stats->start_idle_time)
bfq_stat_add(&stats->idle_time,
now - stats->start_idle_time);
bfqg_stats_clear_idling(stats);
}
}
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
stats->start_idle_time = blk_time_get_ns();
bfqg_stats_mark_idling(stats);
}
void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
bfq_stat_add(&stats->avg_queue_size_sum,
blkg_rwstat_total(&stats->queued));
bfq_stat_add(&stats->avg_queue_size_samples, 1);
bfqg_stats_update_group_wait_time(stats);
}
void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.queued, opf, 1);
bfqg_stats_end_empty_time(&bfqg->stats);
if (!(bfqq == bfqg->bfqd->in_service_queue))
bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq));
}
void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.queued, opf, -1);
}
void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.merged, opf, 1);
}
void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
u64 io_start_time_ns, blk_opf_t opf)
{
struct bfqg_stats *stats = &bfqg->stats;
u64 now = blk_time_get_ns();
if (now > io_start_time_ns)
blkg_rwstat_add(&stats->service_time, opf,
now - io_start_time_ns);
if (io_start_time_ns > start_time_ns)
blkg_rwstat_add(&stats->wait_time, opf,
io_start_time_ns - start_time_ns);
}
#else /* CONFIG_BFQ_CGROUP_DEBUG */
void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf) { }
void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf) { }
void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
u64 io_start_time_ns, blk_opf_t opf) { }
void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
#ifdef CONFIG_BFQ_GROUP_IOSCHED
/*
* blk-cgroup policy-related handlers
* The following functions help in converting between blk-cgroup
* internal structures and BFQ-specific structures.
*/
static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd)
{
return pd ? container_of(pd, struct bfq_group, pd) : NULL;
}
struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg)
{
return pd_to_blkg(&bfqg->pd);
}
static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg)
{
return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq));
}
/*
* 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.
*/
static struct bfq_group *bfqg_parent(struct bfq_group *bfqg)
{
struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent;
return pblkg ? blkg_to_bfqg(pblkg) : NULL;
}
struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
{
struct bfq_entity *group_entity = bfqq->entity.parent;
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.
*/
static void bfqg_get(struct bfq_group *bfqg)
{
refcount_inc(&bfqg->ref);
}
static void bfqg_put(struct bfq_group *bfqg)
{
if (refcount_dec_and_test(&bfqg->ref))
kfree(bfqg);
}
static void bfqg_and_blkg_get(struct bfq_group *bfqg)
{
/* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
bfqg_get(bfqg);
blkg_get(bfqg_to_blkg(bfqg));
}
void bfqg_and_blkg_put(struct bfq_group *bfqg)
{
blkg_put(bfqg_to_blkg(bfqg));
bfqg_put(bfqg);
}
void bfqg_stats_update_legacy_io(struct request_queue *q, struct request *rq)
{
struct bfq_group *bfqg = blkg_to_bfqg(rq->bio->bi_blkg);
if (!bfqg)
return;
blkg_rwstat_add(&bfqg->stats.bytes, rq->cmd_flags, blk_rq_bytes(rq));
blkg_rwstat_add(&bfqg->stats.ios, rq->cmd_flags, 1);
}
/* @stats = 0 */
static void bfqg_stats_reset(struct bfqg_stats *stats)
{
#ifdef CONFIG_BFQ_CGROUP_DEBUG
/* queued stats shouldn't be cleared */
blkg_rwstat_reset(&stats->merged);
blkg_rwstat_reset(&stats->service_time);
blkg_rwstat_reset(&stats->wait_time);
bfq_stat_reset(&stats->time);
bfq_stat_reset(&stats->avg_queue_size_sum);
bfq_stat_reset(&stats->avg_queue_size_samples);
bfq_stat_reset(&stats->dequeue);
bfq_stat_reset(&stats->group_wait_time);
bfq_stat_reset(&stats->idle_time);
bfq_stat_reset(&stats->empty_time);
#endif
}
/* @to += @from */
static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
{
if (!to || !from)
return;
#ifdef CONFIG_BFQ_CGROUP_DEBUG
/* queued stats shouldn't be cleared */
blkg_rwstat_add_aux(&to->merged, &from->merged);
blkg_rwstat_add_aux(&to->service_time, &from->service_time);
blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
bfq_stat_add_aux(&from->time, &from->time);
bfq_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
bfq_stat_add_aux(&to->avg_queue_size_samples,
&from->avg_queue_size_samples);
bfq_stat_add_aux(&to->dequeue, &from->dequeue);
bfq_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
bfq_stat_add_aux(&to->idle_time, &from->idle_time);
bfq_stat_add_aux(&to->empty_time, &from->empty_time);
#endif
}
/*
* Transfer @bfqg's stats to its parent's aux counts so that the ancestors'
* recursive stats can still account for the amount used by this bfqg after
* it's gone.
*/
static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
{
struct bfq_group *parent;
if (!bfqg) /* root_group */
return;
parent = bfqg_parent(bfqg);
lockdep_assert_held(&bfqg_to_blkg(bfqg)->q->queue_lock);
if (unlikely(!parent))
return;
bfqg_stats_add_aux(&parent->stats, &bfqg->stats);
bfqg_stats_reset(&bfqg->stats);
}
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;
if (bfqq) {
bfqq->ioprio = bfqq->new_ioprio;
bfqq->ioprio_class = bfqq->new_ioprio_class;
/*
* Make sure that bfqg and its associated blkg do not
* disappear before entity.
*/
bfqg_and_blkg_get(bfqg);
}
entity->parent = bfqg->my_entity; /* NULL for root group */
entity->sched_data = &bfqg->sched_data;
}
static void bfqg_stats_exit(struct bfqg_stats *stats)
{
blkg_rwstat_exit(&stats->bytes);
blkg_rwstat_exit(&stats->ios);
#ifdef CONFIG_BFQ_CGROUP_DEBUG
blkg_rwstat_exit(&stats->merged);
blkg_rwstat_exit(&stats->service_time);
blkg_rwstat_exit(&stats->wait_time);
blkg_rwstat_exit(&stats->queued);
bfq_stat_exit(&stats->time);
bfq_stat_exit(&stats->avg_queue_size_sum);
bfq_stat_exit(&stats->avg_queue_size_samples);
bfq_stat_exit(&stats->dequeue);
bfq_stat_exit(&stats->group_wait_time);
bfq_stat_exit(&stats->idle_time);
bfq_stat_exit(&stats->empty_time);
#endif
}
static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
{
if (blkg_rwstat_init(&stats->bytes, gfp) ||
blkg_rwstat_init(&stats->ios, gfp))
goto error;
#ifdef CONFIG_BFQ_CGROUP_DEBUG
if (blkg_rwstat_init(&stats->merged, gfp) ||
blkg_rwstat_init(&stats->service_time, gfp) ||
blkg_rwstat_init(&stats->wait_time, gfp) ||
blkg_rwstat_init(&stats->queued, gfp) ||
bfq_stat_init(&stats->time, gfp) ||
bfq_stat_init(&stats->avg_queue_size_sum, gfp) ||
bfq_stat_init(&stats->avg_queue_size_samples, gfp) ||
bfq_stat_init(&stats->dequeue, gfp) ||
bfq_stat_init(&stats->group_wait_time, gfp) ||
bfq_stat_init(&stats->idle_time, gfp) ||
bfq_stat_init(&stats->empty_time, gfp))
goto error;
#endif
return 0;
error:
bfqg_stats_exit(stats);
return -ENOMEM;
}
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 struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp)
{
struct bfq_group_data *bgd;
bgd = kzalloc(sizeof(*bgd), gfp);
if (!bgd)
return NULL;
bgd->weight = CGROUP_WEIGHT_DFL;
return &bgd->pd;
}
static void bfq_cpd_free(struct blkcg_policy_data *cpd)
{
kfree(cpd_to_bfqgd(cpd));
}
static struct blkg_policy_data *bfq_pd_alloc(struct gendisk *disk,
struct blkcg *blkcg, gfp_t gfp)
{
struct bfq_group *bfqg;
bfqg = kzalloc_node(sizeof(*bfqg), gfp, disk->node_id);
if (!bfqg)
return NULL;
if (bfqg_stats_init(&bfqg->stats, gfp)) {
kfree(bfqg);
return NULL;
}
/* see comments in bfq_bic_update_cgroup for why refcounting */
refcount_set(&bfqg->ref, 1);
return &bfqg->pd;
}
static void bfq_pd_init(struct blkg_policy_data *pd)
{
struct blkcg_gq *blkg = pd_to_blkg(pd);
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;
entity->last_bfqq_created = NULL;
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->num_queues_with_pending_reqs = 0;
bfqg->rq_pos_tree = RB_ROOT;
}
static void bfq_pd_free(struct blkg_policy_data *pd)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
bfqg_stats_exit(&bfqg->stats);
bfqg_put(bfqg);
}
static void bfq_pd_reset_stats(struct blkg_policy_data *pd)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
bfqg_stats_reset(&bfqg->stats);
}
static void bfq_group_set_parent(struct bfq_group *bfqg,
struct bfq_group *parent)
{
struct bfq_entity *entity;
entity = &bfqg->entity;
entity->parent = parent->my_entity;
entity->sched_data = &parent->sched_data;
}
static void bfq_link_bfqg(struct bfq_data *bfqd, struct bfq_group *bfqg)
{
struct bfq_group *parent;
struct bfq_entity *entity;
/*
* 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) {
struct bfq_group *curr_bfqg = container_of(entity,
struct bfq_group, entity);
if (curr_bfqg != bfqd->root_group) {
parent = bfqg_parent(curr_bfqg);
if (!parent)
parent = bfqd->root_group;
bfq_group_set_parent(curr_bfqg, parent);
}
}
}
struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
{
struct blkcg_gq *blkg = bio->bi_blkg;
struct bfq_group *bfqg;
while (blkg) {
if (!blkg->online) {
blkg = blkg->parent;
continue;
}
bfqg = blkg_to_bfqg(blkg);
if (bfqg->pd.online) {
bio_associate_blkg_from_css(bio, &blkg->blkcg->css);
return bfqg;
}
blkg = blkg->parent;
}
bio_associate_blkg_from_css(bio,
&bfqg_to_blkg(bfqd->root_group)->blkcg->css);
return bfqd->root_group;
}
/**
* bfq_bfqq_move - migrate @bfqq to @bfqg.
* @bfqd: queue descriptor.
* @bfqq: the queue to move.
* @bfqg: the group to move to.
*
* Move @bfqq to @bfqg, deactivating it from its old group and reactivating
* it on the new one. Avoid putting the entity on the old group idle tree.
*
* Must be called under the scheduler lock, to make sure that the blkg
* owning @bfqg does not disappear (see comments in
* bfq_bic_update_cgroup on guaranteeing the consistency of blkg
* objects).
*/
void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
struct bfq_group *bfqg)
{
struct bfq_entity *entity = &bfqq->entity;
struct bfq_group *old_parent = bfqq_group(bfqq);
bool has_pending_reqs = false;
/*
* No point to move bfqq to the same group, which can happen when
* root group is offlined
*/
if (old_parent == bfqg)
return;
/*
* oom_bfqq is not allowed to move, oom_bfqq will hold ref to root_group
* until elevator exit.
*/
if (bfqq == &bfqd->oom_bfqq)
return;
/*
* Get extra reference to prevent bfqq from being freed in
* next possible expire or deactivate.
*/
bfqq->ref++;
if (entity->in_groups_with_pending_reqs) {
has_pending_reqs = true;
bfq_del_bfqq_in_groups_with_pending_reqs(bfqq);
}
/* If bfqq is empty, then bfq_bfqq_expire also invokes
* bfq_del_bfqq_busy, thereby removing bfqq and its entity
* from data structures related to current group. Otherwise we
* need to remove bfqq explicitly with bfq_deactivate_bfqq, as
* we do below.
*/
if (bfqq == bfqd->in_service_queue)
bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
false, BFQQE_PREEMPTED);
if (bfq_bfqq_busy(bfqq))
bfq_deactivate_bfqq(bfqd, bfqq, false, false);
else if (entity->on_st_or_in_serv)
bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
bfqg_and_blkg_put(old_parent);
bfq_reassign_last_bfqq(bfqq, NULL);
entity->parent = bfqg->my_entity;
entity->sched_data = &bfqg->sched_data;
/* pin down bfqg and its associated blkg */
bfqg_and_blkg_get(bfqg);
if (has_pending_reqs)
bfq_add_bfqq_in_groups_with_pending_reqs(bfqq);
if (bfq_bfqq_busy(bfqq)) {
if (unlikely(!bfqd->nonrot_with_queueing))
bfq_pos_tree_add_move(bfqd, bfqq);
bfq_activate_bfqq(bfqd, bfqq);
}
if (!bfqd->in_service_queue && !bfqd->tot_rq_in_driver)
bfq_schedule_dispatch(bfqd);
/* release extra ref taken above, bfqq may happen to be freed now */
bfq_put_queue(bfqq);
}
static void bfq_sync_bfqq_move(struct bfq_data *bfqd,
struct bfq_queue *sync_bfqq,
struct bfq_io_cq *bic,
struct bfq_group *bfqg,
unsigned int act_idx)
{
struct bfq_queue *bfqq;
if (!sync_bfqq->new_bfqq && !bfq_bfqq_coop(sync_bfqq)) {
/* We are the only user of this bfqq, just move it */
if (sync_bfqq->entity.sched_data != &bfqg->sched_data)
bfq_bfqq_move(bfqd, sync_bfqq, bfqg);
return;
}
/*
* The queue was merged to a different queue. Check
* that the merge chain still belongs to the same
* cgroup.
*/
for (bfqq = sync_bfqq; bfqq; bfqq = bfqq->new_bfqq)
if (bfqq->entity.sched_data != &bfqg->sched_data)
break;
if (bfqq) {
/*
* Some queue changed cgroup so the merge is not valid
* anymore. We cannot easily just cancel the merge (by
* clearing new_bfqq) as there may be other processes
* using this queue and holding refs to all queues
* below sync_bfqq->new_bfqq. Similarly if the merge
* already happened, we need to detach from bfqq now
* so that we cannot merge bio to a request from the
* old cgroup.
*/
bfq_put_cooperator(sync_bfqq);
bic_set_bfqq(bic, NULL, true, act_idx);
}
}
/**
* __bfq_bic_change_cgroup - move @bic to @bfqg.
* @bfqd: the queue descriptor.
* @bic: the bic to move.
* @bfqg: the group to move to.
*
* Move bic to blkcg, assuming that bfqd->lock is held; which makes
* sure that the reference to cgroup is valid across the call (see
* comments in bfq_bic_update_cgroup on this issue)
*/
static void __bfq_bic_change_cgroup(struct bfq_data *bfqd,
struct bfq_io_cq *bic,
struct bfq_group *bfqg)
{
unsigned int act_idx;
for (act_idx = 0; act_idx < bfqd->num_actuators; act_idx++) {
struct bfq_queue *async_bfqq = bic_to_bfqq(bic, false, act_idx);
struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, true, act_idx);
if (async_bfqq &&
async_bfqq->entity.sched_data != &bfqg->sched_data) {
bic_set_bfqq(bic, NULL, false, act_idx);
bfq_release_process_ref(bfqd, async_bfqq);
}
if (sync_bfqq)
bfq_sync_bfqq_move(bfqd, sync_bfqq, bic, bfqg, act_idx);
}
}
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 = bfq_bio_bfqg(bfqd, bio);
uint64_t serial_nr;
serial_nr = bfqg_to_blkg(bfqg)->blkcg->css.serial_nr;
/*
* 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_serial_nr == serial_nr))
return;
/*
* New cgroup for this process. Make sure it is linked to bfq internal
* cgroup hierarchy.
*/
bfq_link_bfqg(bfqd, bfqg);
__bfq_bic_change_cgroup(bfqd, bic, bfqg);
bic->blkcg_serial_nr = serial_nr;
}
/**
* bfq_flush_idle_tree - deactivate any entity on the idle tree of @st.
* @st: the service tree being flushed.
*/
static void bfq_flush_idle_tree(struct bfq_service_tree *st)
{
struct bfq_entity *entity = st->first_idle;
for (; entity ; entity = st->first_idle)
__bfq_deactivate_entity(entity, false);
}
/**
* bfq_reparent_leaf_entity - move leaf entity to the root_group.
* @bfqd: the device data structure with the root group.
* @entity: the entity to move, if entity is a leaf; or the parent entity
* of an active leaf entity to move, if entity is not a leaf.
* @ioprio_class: I/O priority class to reparent.
*/
static void bfq_reparent_leaf_entity(struct bfq_data *bfqd,
struct bfq_entity *entity,
int ioprio_class)
{
struct bfq_queue *bfqq;
struct bfq_entity *child_entity = entity;
while (child_entity->my_sched_data) { /* leaf not reached yet */
struct bfq_sched_data *child_sd = child_entity->my_sched_data;
struct bfq_service_tree *child_st = child_sd->service_tree +
ioprio_class;
struct rb_root *child_active = &child_st->active;
child_entity = bfq_entity_of(rb_first(child_active));
if (!child_entity)
child_entity = child_sd->in_service_entity;
}
bfqq = bfq_entity_to_bfqq(child_entity);
bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
}
/**
* bfq_reparent_active_queues - move to the root group all active queues.
* @bfqd: the device data structure with the root group.
* @bfqg: the group to move from.
* @st: the service tree to start the search from.
* @ioprio_class: I/O priority class to reparent.
*/
static void bfq_reparent_active_queues(struct bfq_data *bfqd,
struct bfq_group *bfqg,
struct bfq_service_tree *st,
int ioprio_class)
{
struct rb_root *active = &st->active;
struct bfq_entity *entity;
while ((entity = bfq_entity_of(rb_first(active))))
bfq_reparent_leaf_entity(bfqd, entity, ioprio_class);
if (bfqg->sched_data.in_service_entity)
bfq_reparent_leaf_entity(bfqd,
bfqg->sched_data.in_service_entity,
ioprio_class);
}
/**
* bfq_pd_offline - deactivate the entity associated with @pd,
* and reparent its children entities.
* @pd: descriptor of the policy going offline.
*
* blkio already grabs the queue_lock for us, so no need to use
* RCU-based magic
*/
static void bfq_pd_offline(struct blkg_policy_data *pd)
{
struct bfq_service_tree *st;
struct bfq_group *bfqg = pd_to_bfqg(pd);
struct bfq_data *bfqd = bfqg->bfqd;
struct bfq_entity *entity = bfqg->my_entity;
unsigned long flags;
int i;
spin_lock_irqsave(&bfqd->lock, flags);
if (!entity) /* root group */
goto put_async_queues;
/*
* Empty all service_trees belonging to this group before
* deactivating the group itself.
*/
for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) {
st = bfqg->sched_data.service_tree + i;
/*
* It may happen that some queues are still active
* (busy) upon group destruction (if the corresponding
* processes have been forced to terminate). We move
* all the leaf entities corresponding to these queues
* to the root_group.
* Also, it may happen that the group has an entity
* in service, which is disconnected from the active
* tree: it must be moved, too.
* There is no need to put the sync queues, as the
* scheduler has taken no reference.
*/
bfq_reparent_active_queues(bfqd, bfqg, st, i);
/*
* The idle tree may still contain bfq_queues
* belonging to exited task because they never
* migrated to a different cgroup from the one being
* destroyed now. In addition, even
* bfq_reparent_active_queues() may happen to add some
* entities to the idle tree. It happens if, in some
* of the calls to bfq_bfqq_move() performed by
* bfq_reparent_active_queues(), the queue to move is
* empty and gets expired.
*/
bfq_flush_idle_tree(st);
}
__bfq_deactivate_entity(entity, false);
put_async_queues:
bfq_put_async_queues(bfqd, bfqg);
spin_unlock_irqrestore(&bfqd->lock, flags);
/*
* @blkg is going offline and will be ignored by
* blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
* that they don't get lost. If IOs complete after this point, the
* stats for them will be lost. Oh well...
*/
bfqg_stats_xfer_dead(bfqg);
}
void bfq_end_wr_async(struct bfq_data *bfqd)
{
struct blkcg_gq *blkg;
list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) {
struct bfq_group *bfqg = blkg_to_bfqg(blkg);
bfq_end_wr_async_queues(bfqd, bfqg);
}
bfq_end_wr_async_queues(bfqd, bfqd->root_group);
}
static int bfq_io_show_weight_legacy(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
unsigned int val = 0;
if (bfqgd)
val = bfqgd->weight;
seq_printf(sf, "%u\n", val);
return 0;
}
static u64 bfqg_prfill_weight_device(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
if (!bfqg->entity.dev_weight)
return 0;
return __blkg_prfill_u64(sf, pd, bfqg->entity.dev_weight);
}
static int bfq_io_show_weight(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
seq_printf(sf, "default %u\n", bfqgd->weight);
blkcg_print_blkgs(sf, blkcg, bfqg_prfill_weight_device,
&blkcg_policy_bfq, 0, false);
return 0;
}
static void bfq_group_set_weight(struct bfq_group *bfqg, u64 weight, u64 dev_weight)
{
weight = dev_weight ?: weight;
bfqg->entity.dev_weight = dev_weight;
/*
* 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)weight != bfqg->entity.new_weight) {
bfqg->entity.new_weight = (unsigned short)weight;
/*
* 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;
}
}
static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css,
struct cftype *cftype,
u64 val)
{
struct blkcg *blkcg = css_to_blkcg(css);
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
struct blkcg_gq *blkg;
int ret = -ERANGE;
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)
bfq_group_set_weight(bfqg, val, 0);
}
spin_unlock_irq(&blkcg->lock);
return ret;
}
static ssize_t bfq_io_set_device_weight(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
int ret;
struct blkg_conf_ctx ctx;
struct blkcg *blkcg = css_to_blkcg(of_css(of));
struct bfq_group *bfqg;
u64 v;
blkg_conf_init(&ctx, buf);
ret = blkg_conf_prep(blkcg, &blkcg_policy_bfq, &ctx);
if (ret)
goto out;
if (sscanf(ctx.body, "%llu", &v) == 1) {
/* require "default" on dfl */
ret = -ERANGE;
if (!v)
goto out;
} else if (!strcmp(strim(ctx.body), "default")) {
v = 0;
} else {
ret = -EINVAL;
goto out;
}
bfqg = blkg_to_bfqg(ctx.blkg);
ret = -ERANGE;
if (!v || (v >= BFQ_MIN_WEIGHT && v <= BFQ_MAX_WEIGHT)) {
bfq_group_set_weight(bfqg, bfqg->entity.weight, v);
ret = 0;
}
out:
blkg_conf_exit(&ctx);
return ret ?: nbytes;
}
static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
char *endp;
int ret;
u64 v;
buf = strim(buf);
/* "WEIGHT" or "default WEIGHT" sets the default weight */
v = simple_strtoull(buf, &endp, 0);
if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
ret = bfq_io_set_weight_legacy(of_css(of), NULL, v);
return ret ?: nbytes;
}
return bfq_io_set_device_weight(of, buf, nbytes, off);
}
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 u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkg_rwstat_sample sum;
blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off, &sum);
return __blkg_prfill_rwstat(sf, pd, &sum);
}
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;
}
#ifdef CONFIG_BFQ_CGROUP_DEBUG
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 u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkcg_gq *blkg = pd_to_blkg(pd);
struct blkcg_gq *pos_blkg;
struct cgroup_subsys_state *pos_css;
u64 sum = 0;
lockdep_assert_held(&blkg->q->queue_lock);
rcu_read_lock();
blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
struct bfq_stat *stat;
if (!pos_blkg->online)
continue;
stat = (void *)blkg_to_pd(pos_blkg, &blkcg_policy_bfq) + off;
sum += bfq_stat_read(stat) + atomic64_read(&stat->aux_cnt);
}
rcu_read_unlock();
return __blkg_prfill_u64(sf, pd, sum);
}
static int bfqg_print_stat_recursive(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_stat_recursive, &blkcg_policy_bfq,
seq_cft(sf)->private, false);
return 0;
}
static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
struct bfq_group *bfqg = blkg_to_bfqg(pd->blkg);
u64 sum = blkg_rwstat_total(&bfqg->stats.bytes);
return __blkg_prfill_u64(sf, pd, sum >> 9);
}
static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false);
return 0;
}
static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkg_rwstat_sample tmp;
blkg_rwstat_recursive_sum(pd->blkg, &blkcg_policy_bfq,
offsetof(struct bfq_group, stats.bytes), &tmp);
return __blkg_prfill_u64(sf, pd,
(tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]) >> 9);
}
static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0,
false);
return 0;
}
static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
u64 samples = bfq_stat_read(&bfqg->stats.avg_queue_size_samples);
u64 v = 0;
if (samples) {
v = bfq_stat_read(&bfqg->stats.avg_queue_size_sum);
v = div64_u64(v, samples);
}
__blkg_prfill_u64(sf, pd, v);
return 0;
}
/* print avg_queue_size */
static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_avg_queue_size, &blkcg_policy_bfq,
0, false);
return 0;
}
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
{
int ret;
ret = blkcg_activate_policy(bfqd->queue->disk, &blkcg_policy_bfq);
if (ret)
return NULL;
return blkg_to_bfqg(bfqd->queue->root_blkg);
}
struct blkcg_policy blkcg_policy_bfq = {
.dfl_cftypes = bfq_blkg_files,
.legacy_cftypes = bfq_blkcg_legacy_files,
.cpd_alloc_fn = bfq_cpd_alloc,
.cpd_free_fn = bfq_cpd_free,
.pd_alloc_fn = bfq_pd_alloc,
.pd_init_fn = bfq_pd_init,
.pd_offline_fn = bfq_pd_offline,
.pd_free_fn = bfq_pd_free,
.pd_reset_stats_fn = bfq_pd_reset_stats,
};
struct cftype bfq_blkcg_legacy_files[] = {
{
.name = "bfq.weight",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight_legacy,
.write_u64 = bfq_io_set_weight_legacy,
},
{
.name = "bfq.weight_device",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight,
.write = bfq_io_set_weight,
},
/* statistics, covers only the tasks in the bfqg */
{
.name = "bfq.io_service_bytes",
.private = offsetof(struct bfq_group, stats.bytes),
.seq_show = bfqg_print_rwstat,
},
{
.name = "bfq.io_serviced",
.private = offsetof(struct bfq_group, stats.ios),
.seq_show = bfqg_print_rwstat,
},
#ifdef CONFIG_BFQ_CGROUP_DEBUG
{
.name = "bfq.time",
.private = offsetof(struct bfq_group, stats.time),
.seq_show = bfqg_print_stat,
},
{
.name = "bfq.sectors",
.seq_show = bfqg_print_stat_sectors,
},
{
.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,
},
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
/* the same statistics which cover the bfqg and its descendants */
{
.name = "bfq.io_service_bytes_recursive",
.private = offsetof(struct bfq_group, stats.bytes),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.io_serviced_recursive",
.private = offsetof(struct bfq_group, stats.ios),
.seq_show = bfqg_print_rwstat_recursive,
},
#ifdef CONFIG_BFQ_CGROUP_DEBUG
{
.name = "bfq.time_recursive",
.private = offsetof(struct bfq_group, stats.time),
.seq_show = bfqg_print_stat_recursive,
},
{
.name = "bfq.sectors_recursive",
.seq_show = bfqg_print_stat_sectors_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,
},
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
{ } /* terminate */
};
struct cftype bfq_blkg_files[] = {
{
.name = "bfq.weight",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight,
.write = bfq_io_set_weight,
},
{} /* terminate */
};
#else /* CONFIG_BFQ_GROUP_IOSCHED */
void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
struct bfq_group *bfqg) {}
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;
if (bfqq) {
bfqq->ioprio = bfqq->new_ioprio;
bfqq->ioprio_class = bfqq->new_ioprio_class;
}
entity->sched_data = &bfqg->sched_data;
}
void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) {}
void bfq_end_wr_async(struct bfq_data *bfqd)
{
bfq_end_wr_async_queues(bfqd, bfqd->root_group);
}
struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
{
return bfqd->root_group;
}
struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
{
return bfqq->bfqd->root_group;
}
void bfqg_and_blkg_put(struct bfq_group *bfqg) {}
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)
return NULL;
for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
return bfqg;
}
#endif /* CONFIG_BFQ_GROUP_IOSCHED */
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