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- // SPDX-License-Identifier: GPL-2.0
- /*
- * MQ Deadline i/o scheduler - adaptation of the legacy deadline scheduler,
- * for the blk-mq scheduling framework
- *
- * Copyright (C) 2016 Jens Axboe <axboe@kernel.dk>
- */
- #include <linux/kernel.h>
- #include <linux/fs.h>
- #include <linux/blkdev.h>
- #include <linux/blk-mq.h>
- #include <linux/elevator.h>
- #include <linux/bio.h>
- #include <linux/module.h>
- #include <linux/slab.h>
- #include <linux/init.h>
- #include <linux/compiler.h>
- #include <linux/rbtree.h>
- #include <linux/sbitmap.h>
- #include "blk.h"
- #include "blk-mq.h"
- #include "blk-mq-debugfs.h"
- #include "blk-mq-tag.h"
- #include "blk-mq-sched.h"
- #include "mq-deadline-cgroup.h"
- /*
- * See Documentation/block/deadline-iosched.rst
- */
- static const int read_expire = HZ / 2; /* max time before a read is submitted. */
- static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
- /*
- * Time after which to dispatch lower priority requests even if higher
- * priority requests are pending.
- */
- static const int aging_expire = 10 * HZ;
- static const int writes_starved = 2; /* max times reads can starve a write */
- static const int fifo_batch = 16; /* # of sequential requests treated as one
- by the above parameters. For throughput. */
- enum dd_data_dir {
- DD_READ = READ,
- DD_WRITE = WRITE,
- };
- enum { DD_DIR_COUNT = 2 };
- enum dd_prio {
- DD_RT_PRIO = 0,
- DD_BE_PRIO = 1,
- DD_IDLE_PRIO = 2,
- DD_PRIO_MAX = 2,
- };
- enum { DD_PRIO_COUNT = 3 };
- /* I/O statistics for all I/O priorities (enum dd_prio). */
- struct io_stats {
- struct io_stats_per_prio stats[DD_PRIO_COUNT];
- };
- /*
- * Deadline scheduler data per I/O priority (enum dd_prio). Requests are
- * present on both sort_list[] and fifo_list[].
- */
- struct dd_per_prio {
- struct list_head dispatch;
- struct rb_root sort_list[DD_DIR_COUNT];
- struct list_head fifo_list[DD_DIR_COUNT];
- /* Next request in FIFO order. Read, write or both are NULL. */
- struct request *next_rq[DD_DIR_COUNT];
- };
- struct deadline_data {
- /*
- * run time data
- */
- /* Request queue that owns this data structure. */
- struct request_queue *queue;
- struct dd_per_prio per_prio[DD_PRIO_COUNT];
- /* Data direction of latest dispatched request. */
- enum dd_data_dir last_dir;
- unsigned int batching; /* number of sequential requests made */
- unsigned int starved; /* times reads have starved writes */
- struct io_stats __percpu *stats;
- /*
- * settings that change how the i/o scheduler behaves
- */
- int fifo_expire[DD_DIR_COUNT];
- int fifo_batch;
- int writes_starved;
- int front_merges;
- u32 async_depth;
- int aging_expire;
- spinlock_t lock;
- spinlock_t zone_lock;
- };
- /* Count one event of type 'event_type' and with I/O priority 'prio' */
- #define dd_count(dd, event_type, prio) do { \
- struct io_stats *io_stats = get_cpu_ptr((dd)->stats); \
- \
- BUILD_BUG_ON(!__same_type((dd), struct deadline_data *)); \
- BUILD_BUG_ON(!__same_type((prio), enum dd_prio)); \
- local_inc(&io_stats->stats[(prio)].event_type); \
- put_cpu_ptr(io_stats); \
- } while (0)
- /*
- * Returns the total number of dd_count(dd, event_type, prio) calls across all
- * CPUs. No locking or barriers since it is fine if the returned sum is slightly
- * outdated.
- */
- #define dd_sum(dd, event_type, prio) ({ \
- unsigned int cpu; \
- u32 sum = 0; \
- \
- BUILD_BUG_ON(!__same_type((dd), struct deadline_data *)); \
- BUILD_BUG_ON(!__same_type((prio), enum dd_prio)); \
- for_each_present_cpu(cpu) \
- sum += local_read(&per_cpu_ptr((dd)->stats, cpu)-> \
- stats[(prio)].event_type); \
- sum; \
- })
- /* Maps an I/O priority class to a deadline scheduler priority. */
- static const enum dd_prio ioprio_class_to_prio[] = {
- [IOPRIO_CLASS_NONE] = DD_BE_PRIO,
- [IOPRIO_CLASS_RT] = DD_RT_PRIO,
- [IOPRIO_CLASS_BE] = DD_BE_PRIO,
- [IOPRIO_CLASS_IDLE] = DD_IDLE_PRIO,
- };
- static inline struct rb_root *
- deadline_rb_root(struct dd_per_prio *per_prio, struct request *rq)
- {
- return &per_prio->sort_list[rq_data_dir(rq)];
- }
- /*
- * Returns the I/O priority class (IOPRIO_CLASS_*) that has been assigned to a
- * request.
- */
- static u8 dd_rq_ioclass(struct request *rq)
- {
- return IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
- }
- /*
- * get the request after `rq' in sector-sorted order
- */
- static inline struct request *
- deadline_latter_request(struct request *rq)
- {
- struct rb_node *node = rb_next(&rq->rb_node);
- if (node)
- return rb_entry_rq(node);
- return NULL;
- }
- static void
- deadline_add_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
- {
- struct rb_root *root = deadline_rb_root(per_prio, rq);
- elv_rb_add(root, rq);
- }
- static inline void
- deadline_del_rq_rb(struct dd_per_prio *per_prio, struct request *rq)
- {
- const enum dd_data_dir data_dir = rq_data_dir(rq);
- if (per_prio->next_rq[data_dir] == rq)
- per_prio->next_rq[data_dir] = deadline_latter_request(rq);
- elv_rb_del(deadline_rb_root(per_prio, rq), rq);
- }
- /*
- * remove rq from rbtree and fifo.
- */
- static void deadline_remove_request(struct request_queue *q,
- struct dd_per_prio *per_prio,
- struct request *rq)
- {
- list_del_init(&rq->queuelist);
- /*
- * We might not be on the rbtree, if we are doing an insert merge
- */
- if (!RB_EMPTY_NODE(&rq->rb_node))
- deadline_del_rq_rb(per_prio, rq);
- elv_rqhash_del(q, rq);
- if (q->last_merge == rq)
- q->last_merge = NULL;
- }
- static void dd_request_merged(struct request_queue *q, struct request *req,
- enum elv_merge type)
- {
- struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(req);
- const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
- /*
- * if the merge was a front merge, we need to reposition request
- */
- if (type == ELEVATOR_FRONT_MERGE) {
- elv_rb_del(deadline_rb_root(per_prio, req), req);
- deadline_add_rq_rb(per_prio, req);
- }
- }
- /*
- * Callback function that is invoked after @next has been merged into @req.
- */
- static void dd_merged_requests(struct request_queue *q, struct request *req,
- struct request *next)
- {
- struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(next);
- const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- struct dd_blkcg *blkcg = next->elv.priv[0];
- dd_count(dd, merged, prio);
- ddcg_count(blkcg, merged, ioprio_class);
- /*
- * if next expires before rq, assign its expire time to rq
- * and move into next position (next will be deleted) in fifo
- */
- if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
- if (time_before((unsigned long)next->fifo_time,
- (unsigned long)req->fifo_time)) {
- list_move(&req->queuelist, &next->queuelist);
- req->fifo_time = next->fifo_time;
- }
- }
- /*
- * kill knowledge of next, this one is a goner
- */
- deadline_remove_request(q, &dd->per_prio[prio], next);
- }
- /*
- * move an entry to dispatch queue
- */
- static void
- deadline_move_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
- struct request *rq)
- {
- const enum dd_data_dir data_dir = rq_data_dir(rq);
- per_prio->next_rq[data_dir] = deadline_latter_request(rq);
- /*
- * take it off the sort and fifo list
- */
- deadline_remove_request(rq->q, per_prio, rq);
- }
- /* Number of requests queued for a given priority level. */
- static u32 dd_queued(struct deadline_data *dd, enum dd_prio prio)
- {
- return dd_sum(dd, inserted, prio) - dd_sum(dd, completed, prio);
- }
- /*
- * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
- * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
- */
- static inline int deadline_check_fifo(struct dd_per_prio *per_prio,
- enum dd_data_dir data_dir)
- {
- struct request *rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
- /*
- * rq is expired!
- */
- if (time_after_eq(jiffies, (unsigned long)rq->fifo_time))
- return 1;
- return 0;
- }
- /*
- * For the specified data direction, return the next request to
- * dispatch using arrival ordered lists.
- */
- static struct request *
- deadline_fifo_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
- enum dd_data_dir data_dir)
- {
- struct request *rq;
- unsigned long flags;
- if (list_empty(&per_prio->fifo_list[data_dir]))
- return NULL;
- rq = rq_entry_fifo(per_prio->fifo_list[data_dir].next);
- if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
- return rq;
- /*
- * Look for a write request that can be dispatched, that is one with
- * an unlocked target zone.
- */
- spin_lock_irqsave(&dd->zone_lock, flags);
- list_for_each_entry(rq, &per_prio->fifo_list[DD_WRITE], queuelist) {
- if (blk_req_can_dispatch_to_zone(rq))
- goto out;
- }
- rq = NULL;
- out:
- spin_unlock_irqrestore(&dd->zone_lock, flags);
- return rq;
- }
- /*
- * For the specified data direction, return the next request to
- * dispatch using sector position sorted lists.
- */
- static struct request *
- deadline_next_request(struct deadline_data *dd, struct dd_per_prio *per_prio,
- enum dd_data_dir data_dir)
- {
- struct request *rq;
- unsigned long flags;
- rq = per_prio->next_rq[data_dir];
- if (!rq)
- return NULL;
- if (data_dir == DD_READ || !blk_queue_is_zoned(rq->q))
- return rq;
- /*
- * Look for a write request that can be dispatched, that is one with
- * an unlocked target zone.
- */
- spin_lock_irqsave(&dd->zone_lock, flags);
- while (rq) {
- if (blk_req_can_dispatch_to_zone(rq))
- break;
- rq = deadline_latter_request(rq);
- }
- spin_unlock_irqrestore(&dd->zone_lock, flags);
- return rq;
- }
- /*
- * deadline_dispatch_requests selects the best request according to
- * read/write expire, fifo_batch, etc and with a start time <= @latest.
- */
- static struct request *__dd_dispatch_request(struct deadline_data *dd,
- struct dd_per_prio *per_prio,
- u64 latest_start_ns)
- {
- struct request *rq, *next_rq;
- enum dd_data_dir data_dir;
- struct dd_blkcg *blkcg;
- enum dd_prio prio;
- u8 ioprio_class;
- lockdep_assert_held(&dd->lock);
- if (!list_empty(&per_prio->dispatch)) {
- rq = list_first_entry(&per_prio->dispatch, struct request,
- queuelist);
- if (rq->start_time_ns > latest_start_ns)
- return NULL;
- list_del_init(&rq->queuelist);
- goto done;
- }
- /*
- * batches are currently reads XOR writes
- */
- rq = deadline_next_request(dd, per_prio, dd->last_dir);
- if (rq && dd->batching < dd->fifo_batch)
- /* we have a next request are still entitled to batch */
- goto dispatch_request;
- /*
- * at this point we are not running a batch. select the appropriate
- * data direction (read / write)
- */
- if (!list_empty(&per_prio->fifo_list[DD_READ])) {
- BUG_ON(RB_EMPTY_ROOT(&per_prio->sort_list[DD_READ]));
- if (deadline_fifo_request(dd, per_prio, DD_WRITE) &&
- (dd->starved++ >= dd->writes_starved))
- goto dispatch_writes;
- data_dir = DD_READ;
- goto dispatch_find_request;
- }
- /*
- * there are either no reads or writes have been starved
- */
- if (!list_empty(&per_prio->fifo_list[DD_WRITE])) {
- dispatch_writes:
- BUG_ON(RB_EMPTY_ROOT(&per_prio->sort_list[DD_WRITE]));
- dd->starved = 0;
- data_dir = DD_WRITE;
- goto dispatch_find_request;
- }
- return NULL;
- dispatch_find_request:
- /*
- * we are not running a batch, find best request for selected data_dir
- */
- next_rq = deadline_next_request(dd, per_prio, data_dir);
- if (deadline_check_fifo(per_prio, data_dir) || !next_rq) {
- /*
- * A deadline has expired, the last request was in the other
- * direction, or we have run out of higher-sectored requests.
- * Start again from the request with the earliest expiry time.
- */
- rq = deadline_fifo_request(dd, per_prio, data_dir);
- } else {
- /*
- * The last req was the same dir and we have a next request in
- * sort order. No expired requests so continue on from here.
- */
- rq = next_rq;
- }
- /*
- * For a zoned block device, if we only have writes queued and none of
- * them can be dispatched, rq will be NULL.
- */
- if (!rq)
- return NULL;
- dd->last_dir = data_dir;
- dd->batching = 0;
- dispatch_request:
- if (rq->start_time_ns > latest_start_ns)
- return NULL;
- /*
- * rq is the selected appropriate request.
- */
- dd->batching++;
- deadline_move_request(dd, per_prio, rq);
- done:
- ioprio_class = dd_rq_ioclass(rq);
- prio = ioprio_class_to_prio[ioprio_class];
- dd_count(dd, dispatched, prio);
- blkcg = rq->elv.priv[0];
- ddcg_count(blkcg, dispatched, ioprio_class);
- /*
- * If the request needs its target zone locked, do it.
- */
- blk_req_zone_write_lock(rq);
- rq->rq_flags |= RQF_STARTED;
- return rq;
- }
- /*
- * Called from blk_mq_run_hw_queue() -> __blk_mq_sched_dispatch_requests().
- *
- * One confusing aspect here is that we get called for a specific
- * hardware queue, but we may return a request that is for a
- * different hardware queue. This is because mq-deadline has shared
- * state for all hardware queues, in terms of sorting, FIFOs, etc.
- */
- static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx)
- {
- struct deadline_data *dd = hctx->queue->elevator->elevator_data;
- const u64 now_ns = ktime_get_ns();
- struct request *rq = NULL;
- enum dd_prio prio;
- spin_lock(&dd->lock);
- /*
- * Start with dispatching requests whose deadline expired more than
- * aging_expire jiffies ago.
- */
- for (prio = DD_BE_PRIO; prio <= DD_PRIO_MAX; prio++) {
- rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now_ns -
- jiffies_to_nsecs(dd->aging_expire));
- if (rq)
- goto unlock;
- }
- /*
- * Next, dispatch requests in priority order. Ignore lower priority
- * requests if any higher priority requests are pending.
- */
- for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
- rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now_ns);
- if (rq || dd_queued(dd, prio))
- break;
- }
- unlock:
- spin_unlock(&dd->lock);
- return rq;
- }
- /*
- * Called by __blk_mq_alloc_request(). The shallow_depth value set by this
- * function is used by __blk_mq_get_tag().
- */
- static void dd_limit_depth(unsigned int op, struct blk_mq_alloc_data *data)
- {
- struct deadline_data *dd = data->q->elevator->elevator_data;
- /* Do not throttle synchronous reads. */
- if (op_is_sync(op) && !op_is_write(op))
- return;
- /*
- * Throttle asynchronous requests and writes such that these requests
- * do not block the allocation of synchronous requests.
- */
- data->shallow_depth = dd->async_depth;
- }
- /* Called by blk_mq_update_nr_requests(). */
- static void dd_depth_updated(struct blk_mq_hw_ctx *hctx)
- {
- struct request_queue *q = hctx->queue;
- struct deadline_data *dd = q->elevator->elevator_data;
- struct blk_mq_tags *tags = hctx->sched_tags;
- dd->async_depth = max(1UL, 3 * q->nr_requests / 4);
- sbitmap_queue_min_shallow_depth(tags->bitmap_tags, dd->async_depth);
- }
- /* Called by blk_mq_init_hctx() and blk_mq_init_sched(). */
- static int dd_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
- {
- dd_depth_updated(hctx);
- return 0;
- }
- static void dd_exit_sched(struct elevator_queue *e)
- {
- struct deadline_data *dd = e->elevator_data;
- enum dd_prio prio;
- dd_deactivate_policy(dd->queue);
- for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
- WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ]));
- WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE]));
- }
- free_percpu(dd->stats);
- kfree(dd);
- }
- /*
- * Initialize elevator private data (deadline_data) and associate with blkcg.
- */
- static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
- {
- struct deadline_data *dd;
- struct elevator_queue *eq;
- enum dd_prio prio;
- int ret = -ENOMEM;
- /*
- * Initialization would be very tricky if the queue is not frozen,
- * hence the warning statement below.
- */
- WARN_ON_ONCE(!percpu_ref_is_zero(&q->q_usage_counter));
- eq = elevator_alloc(q, e);
- if (!eq)
- return ret;
- dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
- if (!dd)
- goto put_eq;
- eq->elevator_data = dd;
- dd->stats = alloc_percpu_gfp(typeof(*dd->stats),
- GFP_KERNEL | __GFP_ZERO);
- if (!dd->stats)
- goto free_dd;
- dd->queue = q;
- for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
- INIT_LIST_HEAD(&per_prio->dispatch);
- INIT_LIST_HEAD(&per_prio->fifo_list[DD_READ]);
- INIT_LIST_HEAD(&per_prio->fifo_list[DD_WRITE]);
- per_prio->sort_list[DD_READ] = RB_ROOT;
- per_prio->sort_list[DD_WRITE] = RB_ROOT;
- }
- dd->fifo_expire[DD_READ] = read_expire;
- dd->fifo_expire[DD_WRITE] = write_expire;
- dd->writes_starved = writes_starved;
- dd->front_merges = 1;
- dd->last_dir = DD_WRITE;
- dd->fifo_batch = fifo_batch;
- dd->aging_expire = aging_expire;
- spin_lock_init(&dd->lock);
- spin_lock_init(&dd->zone_lock);
- ret = dd_activate_policy(q);
- if (ret)
- goto free_stats;
- ret = 0;
- q->elevator = eq;
- return 0;
- free_stats:
- free_percpu(dd->stats);
- free_dd:
- kfree(dd);
- put_eq:
- kobject_put(&eq->kobj);
- return ret;
- }
- /*
- * Try to merge @bio into an existing request. If @bio has been merged into
- * an existing request, store the pointer to that request into *@rq.
- */
- static int dd_request_merge(struct request_queue *q, struct request **rq,
- struct bio *bio)
- {
- struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = IOPRIO_PRIO_CLASS(bio->bi_ioprio);
- const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
- sector_t sector = bio_end_sector(bio);
- struct request *__rq;
- if (!dd->front_merges)
- return ELEVATOR_NO_MERGE;
- __rq = elv_rb_find(&per_prio->sort_list[bio_data_dir(bio)], sector);
- if (__rq) {
- BUG_ON(sector != blk_rq_pos(__rq));
- if (elv_bio_merge_ok(__rq, bio)) {
- *rq = __rq;
- if (blk_discard_mergable(__rq))
- return ELEVATOR_DISCARD_MERGE;
- return ELEVATOR_FRONT_MERGE;
- }
- }
- return ELEVATOR_NO_MERGE;
- }
- /*
- * Attempt to merge a bio into an existing request. This function is called
- * before @bio is associated with a request.
- */
- static bool dd_bio_merge(struct request_queue *q, struct bio *bio,
- unsigned int nr_segs)
- {
- struct deadline_data *dd = q->elevator->elevator_data;
- struct request *free = NULL;
- bool ret;
- spin_lock(&dd->lock);
- ret = blk_mq_sched_try_merge(q, bio, nr_segs, &free);
- spin_unlock(&dd->lock);
- if (free)
- blk_mq_free_request(free);
- return ret;
- }
- /*
- * add rq to rbtree and fifo
- */
- static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
- bool at_head)
- {
- struct request_queue *q = hctx->queue;
- struct deadline_data *dd = q->elevator->elevator_data;
- const enum dd_data_dir data_dir = rq_data_dir(rq);
- u16 ioprio = req_get_ioprio(rq);
- u8 ioprio_class = IOPRIO_PRIO_CLASS(ioprio);
- struct dd_per_prio *per_prio;
- enum dd_prio prio;
- struct dd_blkcg *blkcg;
- lockdep_assert_held(&dd->lock);
- /*
- * This may be a requeue of a write request that has locked its
- * target zone. If it is the case, this releases the zone lock.
- */
- blk_req_zone_write_unlock(rq);
- /*
- * If a block cgroup has been associated with the submitter and if an
- * I/O priority has been set in the associated block cgroup, use the
- * lowest of the cgroup priority and the request priority for the
- * request. If no priority has been set in the request, use the cgroup
- * priority.
- */
- prio = ioprio_class_to_prio[ioprio_class];
- dd_count(dd, inserted, prio);
- blkcg = dd_blkcg_from_bio(rq->bio);
- ddcg_count(blkcg, inserted, ioprio_class);
- rq->elv.priv[0] = blkcg;
- if (blk_mq_sched_try_insert_merge(q, rq))
- return;
- blk_mq_sched_request_inserted(rq);
- per_prio = &dd->per_prio[prio];
- if (at_head) {
- list_add(&rq->queuelist, &per_prio->dispatch);
- } else {
- deadline_add_rq_rb(per_prio, rq);
- if (rq_mergeable(rq)) {
- elv_rqhash_add(q, rq);
- if (!q->last_merge)
- q->last_merge = rq;
- }
- /*
- * set expire time and add to fifo list
- */
- rq->fifo_time = jiffies + dd->fifo_expire[data_dir];
- list_add_tail(&rq->queuelist, &per_prio->fifo_list[data_dir]);
- }
- }
- /*
- * Called from blk_mq_sched_insert_request() or blk_mq_sched_insert_requests().
- */
- static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
- struct list_head *list, bool at_head)
- {
- struct request_queue *q = hctx->queue;
- struct deadline_data *dd = q->elevator->elevator_data;
- spin_lock(&dd->lock);
- while (!list_empty(list)) {
- struct request *rq;
- rq = list_first_entry(list, struct request, queuelist);
- list_del_init(&rq->queuelist);
- dd_insert_request(hctx, rq, at_head);
- }
- spin_unlock(&dd->lock);
- }
- /* Callback from inside blk_mq_rq_ctx_init(). */
- static void dd_prepare_request(struct request *rq)
- {
- rq->elv.priv[0] = NULL;
- }
- /*
- * Callback from inside blk_mq_free_request().
- *
- * For zoned block devices, write unlock the target zone of
- * completed write requests. Do this while holding the zone lock
- * spinlock so that the zone is never unlocked while deadline_fifo_request()
- * or deadline_next_request() are executing. This function is called for
- * all requests, whether or not these requests complete successfully.
- *
- * For a zoned block device, __dd_dispatch_request() may have stopped
- * dispatching requests if all the queued requests are write requests directed
- * at zones that are already locked due to on-going write requests. To ensure
- * write request dispatch progress in this case, mark the queue as needing a
- * restart to ensure that the queue is run again after completion of the
- * request and zones being unlocked.
- */
- static void dd_finish_request(struct request *rq)
- {
- struct request_queue *q = rq->q;
- struct deadline_data *dd = q->elevator->elevator_data;
- struct dd_blkcg *blkcg = rq->elv.priv[0];
- const u8 ioprio_class = dd_rq_ioclass(rq);
- const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
- dd_count(dd, completed, prio);
- ddcg_count(blkcg, completed, ioprio_class);
- if (blk_queue_is_zoned(q)) {
- unsigned long flags;
- spin_lock_irqsave(&dd->zone_lock, flags);
- blk_req_zone_write_unlock(rq);
- if (!list_empty(&per_prio->fifo_list[DD_WRITE]))
- blk_mq_sched_mark_restart_hctx(rq->mq_hctx);
- spin_unlock_irqrestore(&dd->zone_lock, flags);
- }
- }
- static bool dd_has_work_for_prio(struct dd_per_prio *per_prio)
- {
- return !list_empty_careful(&per_prio->dispatch) ||
- !list_empty_careful(&per_prio->fifo_list[DD_READ]) ||
- !list_empty_careful(&per_prio->fifo_list[DD_WRITE]);
- }
- static bool dd_has_work(struct blk_mq_hw_ctx *hctx)
- {
- struct deadline_data *dd = hctx->queue->elevator->elevator_data;
- enum dd_prio prio;
- for (prio = 0; prio <= DD_PRIO_MAX; prio++)
- if (dd_has_work_for_prio(&dd->per_prio[prio]))
- return true;
- return false;
- }
- /*
- * sysfs parts below
- */
- #define SHOW_INT(__FUNC, __VAR) \
- static ssize_t __FUNC(struct elevator_queue *e, char *page) \
- { \
- struct deadline_data *dd = e->elevator_data; \
- \
- return sysfs_emit(page, "%d\n", __VAR); \
- }
- #define SHOW_JIFFIES(__FUNC, __VAR) SHOW_INT(__FUNC, jiffies_to_msecs(__VAR))
- SHOW_JIFFIES(deadline_read_expire_show, dd->fifo_expire[DD_READ]);
- SHOW_JIFFIES(deadline_write_expire_show, dd->fifo_expire[DD_WRITE]);
- SHOW_JIFFIES(deadline_aging_expire_show, dd->aging_expire);
- SHOW_INT(deadline_writes_starved_show, dd->writes_starved);
- SHOW_INT(deadline_front_merges_show, dd->front_merges);
- SHOW_INT(deadline_async_depth_show, dd->front_merges);
- SHOW_INT(deadline_fifo_batch_show, dd->fifo_batch);
- #undef SHOW_INT
- #undef SHOW_JIFFIES
- #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
- static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
- { \
- struct deadline_data *dd = e->elevator_data; \
- int __data, __ret; \
- \
- __ret = kstrtoint(page, 0, &__data); \
- if (__ret < 0) \
- return __ret; \
- if (__data < (MIN)) \
- __data = (MIN); \
- else if (__data > (MAX)) \
- __data = (MAX); \
- *(__PTR) = __CONV(__data); \
- return count; \
- }
- #define STORE_INT(__FUNC, __PTR, MIN, MAX) \
- STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, )
- #define STORE_JIFFIES(__FUNC, __PTR, MIN, MAX) \
- STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, msecs_to_jiffies)
- STORE_JIFFIES(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX);
- STORE_JIFFIES(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX);
- STORE_JIFFIES(deadline_aging_expire_store, &dd->aging_expire, 0, INT_MAX);
- STORE_INT(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX);
- STORE_INT(deadline_front_merges_store, &dd->front_merges, 0, 1);
- STORE_INT(deadline_async_depth_store, &dd->front_merges, 1, INT_MAX);
- STORE_INT(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX);
- #undef STORE_FUNCTION
- #undef STORE_INT
- #undef STORE_JIFFIES
- #define DD_ATTR(name) \
- __ATTR(name, 0644, deadline_##name##_show, deadline_##name##_store)
- static struct elv_fs_entry deadline_attrs[] = {
- DD_ATTR(read_expire),
- DD_ATTR(write_expire),
- DD_ATTR(writes_starved),
- DD_ATTR(front_merges),
- DD_ATTR(async_depth),
- DD_ATTR(fifo_batch),
- DD_ATTR(aging_expire),
- __ATTR_NULL
- };
- #ifdef CONFIG_BLK_DEBUG_FS
- #define DEADLINE_DEBUGFS_DDIR_ATTRS(prio, data_dir, name) \
- static void *deadline_##name##_fifo_start(struct seq_file *m, \
- loff_t *pos) \
- __acquires(&dd->lock) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
- \
- spin_lock(&dd->lock); \
- return seq_list_start(&per_prio->fifo_list[data_dir], *pos); \
- } \
- \
- static void *deadline_##name##_fifo_next(struct seq_file *m, void *v, \
- loff_t *pos) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
- \
- return seq_list_next(v, &per_prio->fifo_list[data_dir], pos); \
- } \
- \
- static void deadline_##name##_fifo_stop(struct seq_file *m, void *v) \
- __releases(&dd->lock) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- \
- spin_unlock(&dd->lock); \
- } \
- \
- static const struct seq_operations deadline_##name##_fifo_seq_ops = { \
- .start = deadline_##name##_fifo_start, \
- .next = deadline_##name##_fifo_next, \
- .stop = deadline_##name##_fifo_stop, \
- .show = blk_mq_debugfs_rq_show, \
- }; \
- \
- static int deadline_##name##_next_rq_show(void *data, \
- struct seq_file *m) \
- { \
- struct request_queue *q = data; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
- struct request *rq = per_prio->next_rq[data_dir]; \
- \
- if (rq) \
- __blk_mq_debugfs_rq_show(m, rq); \
- return 0; \
- }
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_READ, read0);
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_RT_PRIO, DD_WRITE, write0);
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_READ, read1);
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_BE_PRIO, DD_WRITE, write1);
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_READ, read2);
- DEADLINE_DEBUGFS_DDIR_ATTRS(DD_IDLE_PRIO, DD_WRITE, write2);
- #undef DEADLINE_DEBUGFS_DDIR_ATTRS
- static int deadline_batching_show(void *data, struct seq_file *m)
- {
- struct request_queue *q = data;
- struct deadline_data *dd = q->elevator->elevator_data;
- seq_printf(m, "%u\n", dd->batching);
- return 0;
- }
- static int deadline_starved_show(void *data, struct seq_file *m)
- {
- struct request_queue *q = data;
- struct deadline_data *dd = q->elevator->elevator_data;
- seq_printf(m, "%u\n", dd->starved);
- return 0;
- }
- static int dd_async_depth_show(void *data, struct seq_file *m)
- {
- struct request_queue *q = data;
- struct deadline_data *dd = q->elevator->elevator_data;
- seq_printf(m, "%u\n", dd->async_depth);
- return 0;
- }
- static int dd_queued_show(void *data, struct seq_file *m)
- {
- struct request_queue *q = data;
- struct deadline_data *dd = q->elevator->elevator_data;
- seq_printf(m, "%u %u %u\n", dd_queued(dd, DD_RT_PRIO),
- dd_queued(dd, DD_BE_PRIO),
- dd_queued(dd, DD_IDLE_PRIO));
- return 0;
- }
- /* Number of requests owned by the block driver for a given priority. */
- static u32 dd_owned_by_driver(struct deadline_data *dd, enum dd_prio prio)
- {
- return dd_sum(dd, dispatched, prio) + dd_sum(dd, merged, prio)
- - dd_sum(dd, completed, prio);
- }
- static int dd_owned_by_driver_show(void *data, struct seq_file *m)
- {
- struct request_queue *q = data;
- struct deadline_data *dd = q->elevator->elevator_data;
- seq_printf(m, "%u %u %u\n", dd_owned_by_driver(dd, DD_RT_PRIO),
- dd_owned_by_driver(dd, DD_BE_PRIO),
- dd_owned_by_driver(dd, DD_IDLE_PRIO));
- return 0;
- }
- #define DEADLINE_DISPATCH_ATTR(prio) \
- static void *deadline_dispatch##prio##_start(struct seq_file *m, \
- loff_t *pos) \
- __acquires(&dd->lock) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
- \
- spin_lock(&dd->lock); \
- return seq_list_start(&per_prio->dispatch, *pos); \
- } \
- \
- static void *deadline_dispatch##prio##_next(struct seq_file *m, \
- void *v, loff_t *pos) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- struct dd_per_prio *per_prio = &dd->per_prio[prio]; \
- \
- return seq_list_next(v, &per_prio->dispatch, pos); \
- } \
- \
- static void deadline_dispatch##prio##_stop(struct seq_file *m, void *v) \
- __releases(&dd->lock) \
- { \
- struct request_queue *q = m->private; \
- struct deadline_data *dd = q->elevator->elevator_data; \
- \
- spin_unlock(&dd->lock); \
- } \
- \
- static const struct seq_operations deadline_dispatch##prio##_seq_ops = { \
- .start = deadline_dispatch##prio##_start, \
- .next = deadline_dispatch##prio##_next, \
- .stop = deadline_dispatch##prio##_stop, \
- .show = blk_mq_debugfs_rq_show, \
- }
- DEADLINE_DISPATCH_ATTR(0);
- DEADLINE_DISPATCH_ATTR(1);
- DEADLINE_DISPATCH_ATTR(2);
- #undef DEADLINE_DISPATCH_ATTR
- #define DEADLINE_QUEUE_DDIR_ATTRS(name) \
- {#name "_fifo_list", 0400, \
- .seq_ops = &deadline_##name##_fifo_seq_ops}
- #define DEADLINE_NEXT_RQ_ATTR(name) \
- {#name "_next_rq", 0400, deadline_##name##_next_rq_show}
- static const struct blk_mq_debugfs_attr deadline_queue_debugfs_attrs[] = {
- DEADLINE_QUEUE_DDIR_ATTRS(read0),
- DEADLINE_QUEUE_DDIR_ATTRS(write0),
- DEADLINE_QUEUE_DDIR_ATTRS(read1),
- DEADLINE_QUEUE_DDIR_ATTRS(write1),
- DEADLINE_QUEUE_DDIR_ATTRS(read2),
- DEADLINE_QUEUE_DDIR_ATTRS(write2),
- DEADLINE_NEXT_RQ_ATTR(read0),
- DEADLINE_NEXT_RQ_ATTR(write0),
- DEADLINE_NEXT_RQ_ATTR(read1),
- DEADLINE_NEXT_RQ_ATTR(write1),
- DEADLINE_NEXT_RQ_ATTR(read2),
- DEADLINE_NEXT_RQ_ATTR(write2),
- {"batching", 0400, deadline_batching_show},
- {"starved", 0400, deadline_starved_show},
- {"async_depth", 0400, dd_async_depth_show},
- {"dispatch0", 0400, .seq_ops = &deadline_dispatch0_seq_ops},
- {"dispatch1", 0400, .seq_ops = &deadline_dispatch1_seq_ops},
- {"dispatch2", 0400, .seq_ops = &deadline_dispatch2_seq_ops},
- {"owned_by_driver", 0400, dd_owned_by_driver_show},
- {"queued", 0400, dd_queued_show},
- {},
- };
- #undef DEADLINE_QUEUE_DDIR_ATTRS
- #endif
- static struct elevator_type mq_deadline = {
- .ops = {
- .depth_updated = dd_depth_updated,
- .limit_depth = dd_limit_depth,
- .insert_requests = dd_insert_requests,
- .dispatch_request = dd_dispatch_request,
- .prepare_request = dd_prepare_request,
- .finish_request = dd_finish_request,
- .next_request = elv_rb_latter_request,
- .former_request = elv_rb_former_request,
- .bio_merge = dd_bio_merge,
- .request_merge = dd_request_merge,
- .requests_merged = dd_merged_requests,
- .request_merged = dd_request_merged,
- .has_work = dd_has_work,
- .init_sched = dd_init_sched,
- .exit_sched = dd_exit_sched,
- .init_hctx = dd_init_hctx,
- },
- #ifdef CONFIG_BLK_DEBUG_FS
- .queue_debugfs_attrs = deadline_queue_debugfs_attrs,
- #endif
- .elevator_attrs = deadline_attrs,
- .elevator_name = "mq-deadline",
- .elevator_alias = "deadline",
- .elevator_features = ELEVATOR_F_ZBD_SEQ_WRITE,
- .elevator_owner = THIS_MODULE,
- };
- MODULE_ALIAS("mq-deadline-iosched");
- static int __init deadline_init(void)
- {
- int ret;
- ret = elv_register(&mq_deadline);
- if (ret)
- goto out;
- ret = dd_blkcg_init();
- if (ret)
- goto unreg;
- out:
- return ret;
- unreg:
- elv_unregister(&mq_deadline);
- goto out;
- }
- static void __exit deadline_exit(void)
- {
- dd_blkcg_exit();
- elv_unregister(&mq_deadline);
- }
- module_init(deadline_init);
- module_exit(deadline_exit);
- MODULE_AUTHOR("Jens Axboe, Damien Le Moal and Bart Van Assche");
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("MQ deadline IO scheduler");
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