// 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 <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/blkdev.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 <trace/events/block.h>
#include "elevator.h"
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-mq-sched.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 prio_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 per I/O priority. It is fine if these counters overflow.
* What matters is that these counters are at least as wide as
* log2(max_outstanding_requests).
*/
struct io_stats_per_prio {
uint32_t inserted;
uint32_t merged;
uint32_t dispatched;
atomic_t completed;
};
/*
* 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];
/* Position of the most recently dispatched request. */
sector_t latest_pos[DD_DIR_COUNT];
struct io_stats_per_prio stats;
};
struct deadline_data {
/*
* run time data
*/
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 */
/*
* 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 prio_aging_expire;
spinlock_t lock;
};
/* 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));
}
/*
* Return the first request for which blk_rq_pos() >= @pos.
*/
static inline struct request *deadline_from_pos(struct dd_per_prio *per_prio,
enum dd_data_dir data_dir, sector_t pos)
{
struct rb_node *node = per_prio->sort_list[data_dir].rb_node;
struct request *rq, *res = NULL;
if (!node)
return NULL;
rq = rb_entry_rq(node);
while (node) {
rq = rb_entry_rq(node);
if (blk_rq_pos(rq) >= pos) {
res = rq;
node = node->rb_left;
} else {
node = node->rb_right;
}
}
return res;
}
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)
{
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];
lockdep_assert_held(&dd->lock);
dd->per_prio[prio].stats.merged++;
/*
* 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)
{
/*
* 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)
{
const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats;
lockdep_assert_held(&dd->lock);
return stats->inserted - atomic_read(&stats->completed);
}
/*
* deadline_check_fifo returns true if and only if there are expired requests
* in the FIFO list. Requires !list_empty(&dd->fifo_list[data_dir]).
*/
static inline bool 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);
return time_is_before_eq_jiffies((unsigned long)rq->fifo_time);
}
/*
* 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)
{
if (list_empty(&per_prio->fifo_list[data_dir]))
return NULL;
return rq_entry_fifo(per_prio->fifo_list[data_dir].next);
}
/*
* 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)
{
return deadline_from_pos(per_prio, data_dir,
per_prio->latest_pos[data_dir]);
}
/*
* Returns true if and only if @rq started after @latest_start where
* @latest_start is in jiffies.
*/
static bool started_after(struct deadline_data *dd, struct request *rq,
unsigned long latest_start)
{
unsigned long start_time = (unsigned long)rq->fifo_time;
start_time -= dd->fifo_expire[rq_data_dir(rq)];
return time_after(start_time, latest_start);
}
/*
* deadline_dispatch_requests selects the best request according to
* read/write expire, fifo_batch, etc and with a start time <= @latest_start.
*/
static struct request *__dd_dispatch_request(struct deadline_data *dd,
struct dd_per_prio *per_prio,
unsigned long latest_start)
{
struct request *rq, *next_rq;
enum dd_data_dir data_dir;
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 (started_after(dd, rq, latest_start))
return NULL;
list_del_init(&rq->queuelist);
data_dir = rq_data_dir(rq);
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 and are still entitled to batch */
data_dir = rq_data_dir(rq);
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;
}
if (!rq)
return NULL;
dd->last_dir = data_dir;
dd->batching = 0;
dispatch_request:
if (started_after(dd, rq, latest_start))
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->per_prio[prio].latest_pos[data_dir] = blk_rq_pos(rq);
dd->per_prio[prio].stats.dispatched++;
rq->rq_flags |= RQF_STARTED;
return rq;
}
/*
* Check whether there are any requests with priority other than DD_RT_PRIO
* that were inserted more than prio_aging_expire jiffies ago.
*/
static struct request *dd_dispatch_prio_aged_requests(struct deadline_data *dd,
unsigned long now)
{
struct request *rq;
enum dd_prio prio;
int prio_cnt;
lockdep_assert_held(&dd->lock);
prio_cnt = !!dd_queued(dd, DD_RT_PRIO) + !!dd_queued(dd, DD_BE_PRIO) +
!!dd_queued(dd, DD_IDLE_PRIO);
if (prio_cnt < 2)
return NULL;
for (prio = DD_BE_PRIO; prio <= DD_PRIO_MAX; prio++) {
rq = __dd_dispatch_request(dd, &dd->per_prio[prio],
now - dd->prio_aging_expire);
if (rq)
return rq;
}
return NULL;
}
/*
* 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 unsigned long now = jiffies;
struct request *rq;
enum dd_prio prio;
spin_lock(&dd->lock);
rq = dd_dispatch_prio_aged_requests(dd, now);
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);
if (rq || dd_queued(dd, prio))
break;
}
unlock:
spin_unlock(&dd->lock);
return rq;
}
/*
* 'depth' is a number in the range 1..INT_MAX representing a number of
* requests. Scale it with a factor (1 << bt->sb.shift) / q->nr_requests since
* 1..(1 << bt->sb.shift) is the range expected by sbitmap_get_shallow().
* Values larger than q->nr_requests have the same effect as q->nr_requests.
*/
static int dd_to_word_depth(struct blk_mq_hw_ctx *hctx, unsigned int qdepth)
{
struct sbitmap_queue *bt = &hctx->sched_tags->bitmap_tags;
const unsigned int nrr = hctx->queue->nr_requests;
return ((qdepth << bt->sb.shift) + nrr - 1) / nrr;
}
/*
* 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(blk_opf_t opf, struct blk_mq_alloc_data *data)
{
struct deadline_data *dd = data->q->elevator->elevator_data;
/* Do not throttle synchronous reads. */
if (op_is_sync(opf) && !op_is_write(opf))
return;
/*
* Throttle asynchronous requests and writes such that these requests
* do not block the allocation of synchronous requests.
*/
data->shallow_depth = dd_to_word_depth(data->hctx, 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 = q->nr_requests;
sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, 1);
}
/* 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;
for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
struct dd_per_prio *per_prio = &dd->per_prio[prio];
const struct io_stats_per_prio *stats = &per_prio->stats;
uint32_t queued;
WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_READ]));
WARN_ON_ONCE(!list_empty(&per_prio->fifo_list[DD_WRITE]));
spin_lock(&dd->lock);
queued = dd_queued(dd, prio);
spin_unlock(&dd->lock);
WARN_ONCE(queued != 0,
"statistics for priority %d: i %u m %u d %u c %u\n",
prio, stats->inserted, stats->merged,
stats->dispatched, atomic_read(&stats->completed));
}
kfree(dd);
}
/*
* initialize elevator private data (deadline_data).
*/
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;
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;
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->prio_aging_expire = prio_aging_expire;
spin_lock_init(&dd->lock);
/* We dispatch from request queue wide instead of hw queue */
blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q);
q->elevator = eq;
return 0;
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,
blk_insert_t flags, struct list_head *free)
{
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;
lockdep_assert_held(&dd->lock);
prio = ioprio_class_to_prio[ioprio_class];
per_prio = &dd->per_prio[prio];
if (!rq->elv.priv[0]) {
per_prio->stats.inserted++;
rq->elv.priv[0] = (void *)(uintptr_t)1;
}
if (blk_mq_sched_try_insert_merge(q, rq, free))
return;
trace_block_rq_insert(rq);
if (flags & BLK_MQ_INSERT_AT_HEAD) {
list_add(&rq->queuelist, &per_prio->dispatch);
rq->fifo_time = jiffies;
} else {
struct list_head *insert_before;
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];
insert_before = &per_prio->fifo_list[data_dir];
list_add_tail(&rq->queuelist, insert_before);
}
}
/*
* Called from blk_mq_insert_request() or blk_mq_dispatch_plug_list().
*/
static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
struct list_head *list,
blk_insert_t flags)
{
struct request_queue *q = hctx->queue;
struct deadline_data *dd = q->elevator->elevator_data;
LIST_HEAD(free);
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, flags, &free);
}
spin_unlock(&dd->lock);
blk_mq_free_requests(&free);
}
/* 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().
*/
static void dd_finish_request(struct request *rq)
{
struct request_queue *q = rq->q;
struct deadline_data *dd = q->elevator->elevator_data;
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];
/*
* The block layer core may call dd_finish_request() without having
* called dd_insert_requests(). Skip requests that bypassed I/O
* scheduling. See also blk_mq_request_bypass_insert().
*/
if (rq->elv.priv[0])
atomic_inc(&per_prio->stats.completed);
}
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_prio_aging_expire_show, dd->prio_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->async_depth);
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_prio_aging_expire_store, &dd->prio_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->async_depth, 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(prio_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; \
\
rq = deadline_from_pos(per_prio, data_dir, \
per_prio->latest_pos[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;
u32 rt, be, idle;
spin_lock(&dd->lock);
rt = dd_queued(dd, DD_RT_PRIO);
be = dd_queued(dd, DD_BE_PRIO);
idle = dd_queued(dd, DD_IDLE_PRIO);
spin_unlock(&dd->lock);
seq_printf(m, "%u %u %u\n", rt, be, idle);
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)
{
const struct io_stats_per_prio *stats = &dd->per_prio[prio].stats;
lockdep_assert_held(&dd->lock);
return stats->dispatched + stats->merged -
atomic_read(&stats->completed);
}
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;
u32 rt, be, idle;
spin_lock(&dd->lock);
rt = dd_owned_by_driver(dd, DD_RT_PRIO);
be = dd_owned_by_driver(dd, DD_BE_PRIO);
idle = dd_owned_by_driver(dd, DD_IDLE_PRIO);
spin_unlock(&dd->lock);
seq_printf(m, "%u %u %u\n", rt, be, idle);
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_owner = THIS_MODULE,
};
MODULE_ALIAS("mq-deadline-iosched");
static int __init deadline_init(void)
{
return elv_register(&mq_deadline);
}
static void __exit deadline_exit(void)
{
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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