blk-rq-qos: refactor out common elements of blk-wbt

blkcg-qos is going to do essentially what wbt does, only on a cgroup
basis.  Break out the common code that will be shared between blkcg-qos
and wbt into blk-rq-qos.* so they can both utilize the same
infrastructure.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Josef Bacik 2018-07-03 09:32:35 -06:00 committed by Jens Axboe
parent 2ecbf45635
commit a79050434b
10 changed files with 480 additions and 253 deletions

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@ -9,7 +9,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
genhd.o partition-generic.o ioprio.o \
badblocks.o partitions/
badblocks.o partitions/ blk-rq-qos.o
obj-$(CONFIG_BOUNCE) += bounce.o
obj-$(CONFIG_BLK_SCSI_REQUEST) += scsi_ioctl.o

View File

@ -1645,7 +1645,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
blk_delete_timer(rq);
blk_clear_rq_complete(rq);
trace_block_rq_requeue(q, rq);
wbt_requeue(q->rq_wb, rq);
rq_qos_requeue(q, rq);
if (rq->rq_flags & RQF_QUEUED)
blk_queue_end_tag(q, rq);
@ -1752,7 +1752,7 @@ void __blk_put_request(struct request_queue *q, struct request *req)
/* this is a bio leak */
WARN_ON(req->bio != NULL);
wbt_done(q->rq_wb, req);
rq_qos_done(q, req);
/*
* Request may not have originated from ll_rw_blk. if not,
@ -2044,7 +2044,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
}
get_rq:
wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock);
wb_acct = rq_qos_throttle(q, bio, q->queue_lock);
/*
* Grab a free request. This is might sleep but can not fail.
@ -2054,7 +2054,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
req = get_request(q, bio->bi_opf, bio, 0, GFP_NOIO);
if (IS_ERR(req)) {
blk_queue_exit(q);
__wbt_done(q->rq_wb, wb_acct);
rq_qos_cleanup(q, wb_acct);
if (PTR_ERR(req) == -ENOMEM)
bio->bi_status = BLK_STS_RESOURCE;
else
@ -2983,7 +2983,7 @@ void blk_start_request(struct request *req)
req->throtl_size = blk_rq_sectors(req);
#endif
req->rq_flags |= RQF_STATS;
wbt_issue(req->q->rq_wb, req);
rq_qos_issue(req->q, req);
}
BUG_ON(blk_rq_is_complete(req));
@ -3207,7 +3207,7 @@ void blk_finish_request(struct request *req, blk_status_t error)
blk_account_io_done(req, now);
if (req->end_io) {
wbt_done(req->q->rq_wb, req);
rq_qos_done(q, req);
req->end_io(req, error);
} else {
if (blk_bidi_rq(req))

View File

@ -504,7 +504,7 @@ void blk_mq_free_request(struct request *rq)
if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
laptop_io_completion(q->backing_dev_info);
wbt_done(q->rq_wb, rq);
rq_qos_done(q, rq);
if (blk_rq_rl(rq))
blk_put_rl(blk_rq_rl(rq));
@ -527,7 +527,7 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
blk_account_io_done(rq, now);
if (rq->end_io) {
wbt_done(rq->q->rq_wb, rq);
rq_qos_done(rq->q, rq);
rq->end_io(rq, error);
} else {
if (unlikely(blk_bidi_rq(rq)))
@ -641,7 +641,7 @@ void blk_mq_start_request(struct request *rq)
rq->throtl_size = blk_rq_sectors(rq);
#endif
rq->rq_flags |= RQF_STATS;
wbt_issue(q->rq_wb, rq);
rq_qos_issue(q, rq);
}
WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
@ -667,7 +667,7 @@ static void __blk_mq_requeue_request(struct request *rq)
blk_mq_put_driver_tag(rq);
trace_block_rq_requeue(q, rq);
wbt_requeue(q->rq_wb, rq);
rq_qos_requeue(q, rq);
if (blk_mq_request_started(rq)) {
WRITE_ONCE(rq->state, MQ_RQ_IDLE);
@ -1806,13 +1806,13 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
if (blk_mq_sched_bio_merge(q, bio))
return BLK_QC_T_NONE;
wb_acct = wbt_wait(q->rq_wb, bio, NULL);
wb_acct = rq_qos_throttle(q, bio, NULL);
trace_block_getrq(q, bio, bio->bi_opf);
rq = blk_mq_get_request(q, bio, bio->bi_opf, &data);
if (unlikely(!rq)) {
__wbt_done(q->rq_wb, wb_acct);
rq_qos_cleanup(q, wb_acct);
if (bio->bi_opf & REQ_NOWAIT)
bio_wouldblock_error(bio);
return BLK_QC_T_NONE;

178
block/blk-rq-qos.c Normal file
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@ -0,0 +1,178 @@
#include "blk-rq-qos.h"
#include "blk-wbt.h"
/*
* Increment 'v', if 'v' is below 'below'. Returns true if we succeeded,
* false if 'v' + 1 would be bigger than 'below'.
*/
static bool atomic_inc_below(atomic_t *v, int below)
{
int cur = atomic_read(v);
for (;;) {
int old;
if (cur >= below)
return false;
old = atomic_cmpxchg(v, cur, cur + 1);
if (old == cur)
break;
cur = old;
}
return true;
}
bool rq_wait_inc_below(struct rq_wait *rq_wait, int limit)
{
return atomic_inc_below(&rq_wait->inflight, limit);
}
void rq_qos_cleanup(struct request_queue *q, enum wbt_flags wb_acct)
{
struct rq_qos *rqos;
for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->ops->cleanup)
rqos->ops->cleanup(rqos, wb_acct);
}
}
void rq_qos_done(struct request_queue *q, struct request *rq)
{
struct rq_qos *rqos;
for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->ops->done)
rqos->ops->done(rqos, rq);
}
}
void rq_qos_issue(struct request_queue *q, struct request *rq)
{
struct rq_qos *rqos;
for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->ops->issue)
rqos->ops->issue(rqos, rq);
}
}
void rq_qos_requeue(struct request_queue *q, struct request *rq)
{
struct rq_qos *rqos;
for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->ops->requeue)
rqos->ops->requeue(rqos, rq);
}
}
enum wbt_flags rq_qos_throttle(struct request_queue *q, struct bio *bio,
spinlock_t *lock)
{
struct rq_qos *rqos;
enum wbt_flags flags = 0;
for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->ops->throttle)
flags |= rqos->ops->throttle(rqos, bio, lock);
}
return flags;
}
/*
* Return true, if we can't increase the depth further by scaling
*/
bool rq_depth_calc_max_depth(struct rq_depth *rqd)
{
unsigned int depth;
bool ret = false;
/*
* For QD=1 devices, this is a special case. It's important for those
* to have one request ready when one completes, so force a depth of
* 2 for those devices. On the backend, it'll be a depth of 1 anyway,
* since the device can't have more than that in flight. If we're
* scaling down, then keep a setting of 1/1/1.
*/
if (rqd->queue_depth == 1) {
if (rqd->scale_step > 0)
rqd->max_depth = 1;
else {
rqd->max_depth = 2;
ret = true;
}
} else {
/*
* scale_step == 0 is our default state. If we have suffered
* latency spikes, step will be > 0, and we shrink the
* allowed write depths. If step is < 0, we're only doing
* writes, and we allow a temporarily higher depth to
* increase performance.
*/
depth = min_t(unsigned int, rqd->default_depth,
rqd->queue_depth);
if (rqd->scale_step > 0)
depth = 1 + ((depth - 1) >> min(31, rqd->scale_step));
else if (rqd->scale_step < 0) {
unsigned int maxd = 3 * rqd->queue_depth / 4;
depth = 1 + ((depth - 1) << -rqd->scale_step);
if (depth > maxd) {
depth = maxd;
ret = true;
}
}
rqd->max_depth = depth;
}
return ret;
}
void rq_depth_scale_up(struct rq_depth *rqd)
{
/*
* Hit max in previous round, stop here
*/
if (rqd->scaled_max)
return;
rqd->scale_step--;
rqd->scaled_max = rq_depth_calc_max_depth(rqd);
}
/*
* Scale rwb down. If 'hard_throttle' is set, do it quicker, since we
* had a latency violation.
*/
void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
{
/*
* Stop scaling down when we've hit the limit. This also prevents
* ->scale_step from going to crazy values, if the device can't
* keep up.
*/
if (rqd->max_depth == 1)
return;
if (rqd->scale_step < 0 && hard_throttle)
rqd->scale_step = 0;
else
rqd->scale_step++;
rqd->scaled_max = false;
rq_depth_calc_max_depth(rqd);
}
void rq_qos_exit(struct request_queue *q)
{
while (q->rq_qos) {
struct rq_qos *rqos = q->rq_qos;
q->rq_qos = rqos->next;
rqos->ops->exit(rqos);
}
}

106
block/blk-rq-qos.h Normal file
View File

@ -0,0 +1,106 @@
#ifndef RQ_QOS_H
#define RQ_QOS_H
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/blk_types.h>
#include <linux/atomic.h>
#include <linux/wait.h>
enum rq_qos_id {
RQ_QOS_WBT,
RQ_QOS_CGROUP,
};
struct rq_wait {
wait_queue_head_t wait;
atomic_t inflight;
};
struct rq_qos {
struct rq_qos_ops *ops;
struct request_queue *q;
enum rq_qos_id id;
struct rq_qos *next;
};
struct rq_qos_ops {
enum wbt_flags (*throttle)(struct rq_qos *, struct bio *,
spinlock_t *);
void (*issue)(struct rq_qos *, struct request *);
void (*requeue)(struct rq_qos *, struct request *);
void (*done)(struct rq_qos *, struct request *);
void (*cleanup)(struct rq_qos *, enum wbt_flags);
void (*exit)(struct rq_qos *);
};
struct rq_depth {
unsigned int max_depth;
int scale_step;
bool scaled_max;
unsigned int queue_depth;
unsigned int default_depth;
};
static inline struct rq_qos *rq_qos_id(struct request_queue *q,
enum rq_qos_id id)
{
struct rq_qos *rqos;
for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
if (rqos->id == id)
break;
}
return rqos;
}
static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
{
return rq_qos_id(q, RQ_QOS_WBT);
}
static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
{
return rq_qos_id(q, RQ_QOS_CGROUP);
}
static inline void rq_wait_init(struct rq_wait *rq_wait)
{
atomic_set(&rq_wait->inflight, 0);
init_waitqueue_head(&rq_wait->wait);
}
static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
{
rqos->next = q->rq_qos;
q->rq_qos = rqos;
}
static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
{
struct rq_qos *cur, *prev = NULL;
for (cur = q->rq_qos; cur; cur = cur->next) {
if (cur == rqos) {
if (prev)
prev->next = rqos->next;
else
q->rq_qos = cur;
break;
}
prev = cur;
}
}
bool rq_wait_inc_below(struct rq_wait *rq_wait, int limit);
void rq_depth_scale_up(struct rq_depth *rqd);
void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
bool rq_depth_calc_max_depth(struct rq_depth *rqd);
void rq_qos_cleanup(struct request_queue *, enum wbt_flags);
void rq_qos_done(struct request_queue *, struct request *);
void rq_qos_issue(struct request_queue *, struct request *);
void rq_qos_requeue(struct request_queue *, struct request *);
enum wbt_flags rq_qos_throttle(struct request_queue *, struct bio *, spinlock_t *);
void rq_qos_exit(struct request_queue *);
#endif

View File

@ -875,7 +875,7 @@ EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
{
q->queue_depth = depth;
wbt_set_queue_depth(q->rq_wb, depth);
wbt_set_queue_depth(q, depth);
}
EXPORT_SYMBOL(blk_set_queue_depth);
@ -900,7 +900,7 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
queue_flag_clear(QUEUE_FLAG_FUA, q);
spin_unlock_irq(q->queue_lock);
wbt_set_write_cache(q->rq_wb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
}
EXPORT_SYMBOL_GPL(blk_queue_write_cache);

View File

@ -422,16 +422,16 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page,
static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
{
if (!q->rq_wb)
if (!wbt_rq_qos(q))
return -EINVAL;
return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
}
static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
size_t count)
{
struct rq_wb *rwb;
struct rq_qos *rqos;
ssize_t ret;
s64 val;
@ -441,23 +441,21 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
if (val < -1)
return -EINVAL;
rwb = q->rq_wb;
if (!rwb) {
rqos = wbt_rq_qos(q);
if (!rqos) {
ret = wbt_init(q);
if (ret)
return ret;
}
rwb = q->rq_wb;
if (val == -1)
rwb->min_lat_nsec = wbt_default_latency_nsec(q);
val = wbt_default_latency_nsec(q);
else if (val >= 0)
rwb->min_lat_nsec = val * 1000ULL;
val *= 1000ULL;
if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
rwb->enable_state = WBT_STATE_ON_MANUAL;
wbt_set_min_lat(q, val);
wbt_update_limits(rwb);
wbt_update_limits(q);
return count;
}
@ -964,7 +962,7 @@ void blk_unregister_queue(struct gendisk *disk)
kobject_del(&q->kobj);
blk_trace_remove_sysfs(disk_to_dev(disk));
wbt_exit(q);
rq_qos_exit(q);
mutex_lock(&q->sysfs_lock);
if (q->request_fn || (q->mq_ops && q->elevator))

View File

@ -25,6 +25,7 @@
#include <linux/swap.h>
#include "blk-wbt.h"
#include "blk-rq-qos.h"
#define CREATE_TRACE_POINTS
#include <trace/events/wbt.h>
@ -78,28 +79,6 @@ static inline bool rwb_enabled(struct rq_wb *rwb)
return rwb && rwb->wb_normal != 0;
}
/*
* Increment 'v', if 'v' is below 'below'. Returns true if we succeeded,
* false if 'v' + 1 would be bigger than 'below'.
*/
static bool atomic_inc_below(atomic_t *v, int below)
{
int cur = atomic_read(v);
for (;;) {
int old;
if (cur >= below)
return false;
old = atomic_cmpxchg(v, cur, cur + 1);
if (old == cur)
break;
cur = old;
}
return true;
}
static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
{
if (rwb_enabled(rwb)) {
@ -116,7 +95,7 @@ static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
*/
static bool wb_recent_wait(struct rq_wb *rwb)
{
struct bdi_writeback *wb = &rwb->queue->backing_dev_info->wb;
struct bdi_writeback *wb = &rwb->rqos.q->backing_dev_info->wb;
return time_before(jiffies, wb->dirty_sleep + HZ);
}
@ -144,8 +123,9 @@ static void rwb_wake_all(struct rq_wb *rwb)
}
}
void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct)
static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
{
struct rq_wb *rwb = RQWB(rqos);
struct rq_wait *rqw;
int inflight, limit;
@ -194,10 +174,9 @@ void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct)
* Called on completion of a request. Note that it's also called when
* a request is merged, when the request gets freed.
*/
void wbt_done(struct rq_wb *rwb, struct request *rq)
static void wbt_done(struct rq_qos *rqos, struct request *rq)
{
if (!rwb)
return;
struct rq_wb *rwb = RQWB(rqos);
if (!wbt_is_tracked(rq)) {
if (rwb->sync_cookie == rq) {
@ -209,72 +188,11 @@ void wbt_done(struct rq_wb *rwb, struct request *rq)
wb_timestamp(rwb, &rwb->last_comp);
} else {
WARN_ON_ONCE(rq == rwb->sync_cookie);
__wbt_done(rwb, wbt_flags(rq));
__wbt_done(rqos, wbt_flags(rq));
}
wbt_clear_state(rq);
}
/*
* Return true, if we can't increase the depth further by scaling
*/
static bool calc_wb_limits(struct rq_wb *rwb)
{
unsigned int depth;
bool ret = false;
if (!rwb->min_lat_nsec) {
rwb->wb_max = rwb->wb_normal = rwb->wb_background = 0;
return false;
}
/*
* For QD=1 devices, this is a special case. It's important for those
* to have one request ready when one completes, so force a depth of
* 2 for those devices. On the backend, it'll be a depth of 1 anyway,
* since the device can't have more than that in flight. If we're
* scaling down, then keep a setting of 1/1/1.
*/
if (rwb->queue_depth == 1) {
if (rwb->scale_step > 0)
rwb->wb_max = rwb->wb_normal = 1;
else {
rwb->wb_max = rwb->wb_normal = 2;
ret = true;
}
rwb->wb_background = 1;
} else {
/*
* scale_step == 0 is our default state. If we have suffered
* latency spikes, step will be > 0, and we shrink the
* allowed write depths. If step is < 0, we're only doing
* writes, and we allow a temporarily higher depth to
* increase performance.
*/
depth = min_t(unsigned int, RWB_DEF_DEPTH, rwb->queue_depth);
if (rwb->scale_step > 0)
depth = 1 + ((depth - 1) >> min(31, rwb->scale_step));
else if (rwb->scale_step < 0) {
unsigned int maxd = 3 * rwb->queue_depth / 4;
depth = 1 + ((depth - 1) << -rwb->scale_step);
if (depth > maxd) {
depth = maxd;
ret = true;
}
}
/*
* Set our max/normal/bg queue depths based on how far
* we have scaled down (->scale_step).
*/
rwb->wb_max = depth;
rwb->wb_normal = (rwb->wb_max + 1) / 2;
rwb->wb_background = (rwb->wb_max + 3) / 4;
}
return ret;
}
static inline bool stat_sample_valid(struct blk_rq_stat *stat)
{
/*
@ -307,7 +225,8 @@ enum {
static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
{
struct backing_dev_info *bdi = rwb->queue->backing_dev_info;
struct backing_dev_info *bdi = rwb->rqos.q->backing_dev_info;
struct rq_depth *rqd = &rwb->rq_depth;
u64 thislat;
/*
@ -351,7 +270,7 @@ static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
return LAT_EXCEEDED;
}
if (rwb->scale_step)
if (rqd->scale_step)
trace_wbt_stat(bdi, stat);
return LAT_OK;
@ -359,58 +278,48 @@ static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
static void rwb_trace_step(struct rq_wb *rwb, const char *msg)
{
struct backing_dev_info *bdi = rwb->queue->backing_dev_info;
struct backing_dev_info *bdi = rwb->rqos.q->backing_dev_info;
struct rq_depth *rqd = &rwb->rq_depth;
trace_wbt_step(bdi, msg, rwb->scale_step, rwb->cur_win_nsec,
rwb->wb_background, rwb->wb_normal, rwb->wb_max);
trace_wbt_step(bdi, msg, rqd->scale_step, rwb->cur_win_nsec,
rwb->wb_background, rwb->wb_normal, rqd->max_depth);
}
static void calc_wb_limits(struct rq_wb *rwb)
{
if (rwb->min_lat_nsec == 0) {
rwb->wb_normal = rwb->wb_background = 0;
} else if (rwb->rq_depth.max_depth <= 2) {
rwb->wb_normal = rwb->rq_depth.max_depth;
rwb->wb_background = 1;
} else {
rwb->wb_normal = (rwb->rq_depth.max_depth + 1) / 2;
rwb->wb_background = (rwb->rq_depth.max_depth + 3) / 4;
}
}
static void scale_up(struct rq_wb *rwb)
{
/*
* Hit max in previous round, stop here
*/
if (rwb->scaled_max)
return;
rwb->scale_step--;
rq_depth_scale_up(&rwb->rq_depth);
calc_wb_limits(rwb);
rwb->unknown_cnt = 0;
rwb->scaled_max = calc_wb_limits(rwb);
rwb_wake_all(rwb);
rwb_trace_step(rwb, "step up");
rwb_trace_step(rwb, "scale up");
}
/*
* Scale rwb down. If 'hard_throttle' is set, do it quicker, since we
* had a latency violation.
*/
static void scale_down(struct rq_wb *rwb, bool hard_throttle)
{
/*
* Stop scaling down when we've hit the limit. This also prevents
* ->scale_step from going to crazy values, if the device can't
* keep up.
*/
if (rwb->wb_max == 1)
return;
if (rwb->scale_step < 0 && hard_throttle)
rwb->scale_step = 0;
else
rwb->scale_step++;
rwb->scaled_max = false;
rwb->unknown_cnt = 0;
rq_depth_scale_down(&rwb->rq_depth, hard_throttle);
calc_wb_limits(rwb);
rwb_trace_step(rwb, "step down");
rwb->unknown_cnt = 0;
rwb_wake_all(rwb);
rwb_trace_step(rwb, "scale down");
}
static void rwb_arm_timer(struct rq_wb *rwb)
{
if (rwb->scale_step > 0) {
struct rq_depth *rqd = &rwb->rq_depth;
if (rqd->scale_step > 0) {
/*
* We should speed this up, using some variant of a fast
* integer inverse square root calculation. Since we only do
@ -418,7 +327,7 @@ static void rwb_arm_timer(struct rq_wb *rwb)
* though.
*/
rwb->cur_win_nsec = div_u64(rwb->win_nsec << 4,
int_sqrt((rwb->scale_step + 1) << 8));
int_sqrt((rqd->scale_step + 1) << 8));
} else {
/*
* For step < 0, we don't want to increase/decrease the
@ -433,12 +342,13 @@ static void rwb_arm_timer(struct rq_wb *rwb)
static void wb_timer_fn(struct blk_stat_callback *cb)
{
struct rq_wb *rwb = cb->data;
struct rq_depth *rqd = &rwb->rq_depth;
unsigned int inflight = wbt_inflight(rwb);
int status;
status = latency_exceeded(rwb, cb->stat);
trace_wbt_timer(rwb->queue->backing_dev_info, status, rwb->scale_step,
trace_wbt_timer(rwb->rqos.q->backing_dev_info, status, rqd->scale_step,
inflight);
/*
@ -469,9 +379,9 @@ static void wb_timer_fn(struct blk_stat_callback *cb)
* currently don't have a valid read/write sample. For that
* case, slowly return to center state (step == 0).
*/
if (rwb->scale_step > 0)
if (rqd->scale_step > 0)
scale_up(rwb);
else if (rwb->scale_step < 0)
else if (rqd->scale_step < 0)
scale_down(rwb, false);
break;
default:
@ -481,19 +391,50 @@ static void wb_timer_fn(struct blk_stat_callback *cb)
/*
* Re-arm timer, if we have IO in flight
*/
if (rwb->scale_step || inflight)
if (rqd->scale_step || inflight)
rwb_arm_timer(rwb);
}
void wbt_update_limits(struct rq_wb *rwb)
static void __wbt_update_limits(struct rq_wb *rwb)
{
rwb->scale_step = 0;
rwb->scaled_max = false;
struct rq_depth *rqd = &rwb->rq_depth;
rqd->scale_step = 0;
rqd->scaled_max = false;
rq_depth_calc_max_depth(rqd);
calc_wb_limits(rwb);
rwb_wake_all(rwb);
}
void wbt_update_limits(struct request_queue *q)
{
struct rq_qos *rqos = wbt_rq_qos(q);
if (!rqos)
return;
__wbt_update_limits(RQWB(rqos));
}
u64 wbt_get_min_lat(struct request_queue *q)
{
struct rq_qos *rqos = wbt_rq_qos(q);
if (!rqos)
return 0;
return RQWB(rqos)->min_lat_nsec;
}
void wbt_set_min_lat(struct request_queue *q, u64 val)
{
struct rq_qos *rqos = wbt_rq_qos(q);
if (!rqos)
return;
RQWB(rqos)->min_lat_nsec = val;
RQWB(rqos)->enable_state = WBT_STATE_ON_MANUAL;
__wbt_update_limits(RQWB(rqos));
}
static bool close_io(struct rq_wb *rwb)
{
const unsigned long now = jiffies;
@ -520,7 +461,7 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw)
* IO for a bit.
*/
if ((rw & REQ_HIPRIO) || wb_recent_wait(rwb) || current_is_kswapd())
limit = rwb->wb_max;
limit = rwb->rq_depth.max_depth;
else if ((rw & REQ_BACKGROUND) || close_io(rwb)) {
/*
* If less than 100ms since we completed unrelated IO,
@ -554,7 +495,7 @@ static inline bool may_queue(struct rq_wb *rwb, struct rq_wait *rqw,
rqw->wait.head.next != &wait->entry)
return false;
return atomic_inc_below(&rqw->inflight, get_limit(rwb, rw));
return rq_wait_inc_below(rqw, get_limit(rwb, rw));
}
/*
@ -614,8 +555,10 @@ static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)
* in an irq held spinlock, if it holds one when calling this function.
* If we do sleep, we'll release and re-grab it.
*/
enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock)
static enum wbt_flags wbt_wait(struct rq_qos *rqos, struct bio *bio,
spinlock_t *lock)
{
struct rq_wb *rwb = RQWB(rqos);
enum wbt_flags ret = 0;
if (!rwb_enabled(rwb))
@ -643,8 +586,10 @@ enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock)
return ret | WBT_TRACKED;
}
void wbt_issue(struct rq_wb *rwb, struct request *rq)
void wbt_issue(struct rq_qos *rqos, struct request *rq)
{
struct rq_wb *rwb = RQWB(rqos);
if (!rwb_enabled(rwb))
return;
@ -661,8 +606,9 @@ void wbt_issue(struct rq_wb *rwb, struct request *rq)
}
}
void wbt_requeue(struct rq_wb *rwb, struct request *rq)
void wbt_requeue(struct rq_qos *rqos, struct request *rq)
{
struct rq_wb *rwb = RQWB(rqos);
if (!rwb_enabled(rwb))
return;
if (rq == rwb->sync_cookie) {
@ -671,39 +617,30 @@ void wbt_requeue(struct rq_wb *rwb, struct request *rq)
}
}
void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
void wbt_set_queue_depth(struct request_queue *q, unsigned int depth)
{
if (rwb) {
rwb->queue_depth = depth;
wbt_update_limits(rwb);
struct rq_qos *rqos = wbt_rq_qos(q);
if (rqos) {
RQWB(rqos)->rq_depth.queue_depth = depth;
__wbt_update_limits(RQWB(rqos));
}
}
void wbt_set_write_cache(struct rq_wb *rwb, bool write_cache_on)
void wbt_set_write_cache(struct request_queue *q, bool write_cache_on)
{
if (rwb)
rwb->wc = write_cache_on;
struct rq_qos *rqos = wbt_rq_qos(q);
if (rqos)
RQWB(rqos)->wc = write_cache_on;
}
/*
* Disable wbt, if enabled by default.
*/
void wbt_disable_default(struct request_queue *q)
{
struct rq_wb *rwb = q->rq_wb;
if (rwb && rwb->enable_state == WBT_STATE_ON_DEFAULT)
wbt_exit(q);
}
EXPORT_SYMBOL_GPL(wbt_disable_default);
/*
* Enable wbt if defaults are configured that way
*/
void wbt_enable_default(struct request_queue *q)
{
struct rq_qos *rqos = wbt_rq_qos(q);
/* Throttling already enabled? */
if (q->rq_wb)
if (rqos)
return;
/* Queue not registered? Maybe shutting down... */
@ -741,6 +678,41 @@ static int wbt_data_dir(const struct request *rq)
return -1;
}
static void wbt_exit(struct rq_qos *rqos)
{
struct rq_wb *rwb = RQWB(rqos);
struct request_queue *q = rqos->q;
blk_stat_remove_callback(q, rwb->cb);
blk_stat_free_callback(rwb->cb);
kfree(rwb);
}
/*
* Disable wbt, if enabled by default.
*/
void wbt_disable_default(struct request_queue *q)
{
struct rq_qos *rqos = wbt_rq_qos(q);
struct rq_wb *rwb;
if (!rqos)
return;
rwb = RQWB(rqos);
if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
rwb->wb_normal = 0;
}
EXPORT_SYMBOL_GPL(wbt_disable_default);
static struct rq_qos_ops wbt_rqos_ops = {
.throttle = wbt_wait,
.issue = wbt_issue,
.requeue = wbt_requeue,
.done = wbt_done,
.cleanup = __wbt_done,
.exit = wbt_exit,
};
int wbt_init(struct request_queue *q)
{
struct rq_wb *rwb;
@ -756,39 +728,29 @@ int wbt_init(struct request_queue *q)
return -ENOMEM;
}
for (i = 0; i < WBT_NUM_RWQ; i++) {
atomic_set(&rwb->rq_wait[i].inflight, 0);
init_waitqueue_head(&rwb->rq_wait[i].wait);
}
for (i = 0; i < WBT_NUM_RWQ; i++)
rq_wait_init(&rwb->rq_wait[i]);
rwb->rqos.id = RQ_QOS_WBT;
rwb->rqos.ops = &wbt_rqos_ops;
rwb->rqos.q = q;
rwb->last_comp = rwb->last_issue = jiffies;
rwb->queue = q;
rwb->win_nsec = RWB_WINDOW_NSEC;
rwb->enable_state = WBT_STATE_ON_DEFAULT;
wbt_update_limits(rwb);
rwb->wc = 1;
rwb->rq_depth.default_depth = RWB_DEF_DEPTH;
__wbt_update_limits(rwb);
/*
* Assign rwb and add the stats callback.
*/
q->rq_wb = rwb;
rq_qos_add(q, &rwb->rqos);
blk_stat_add_callback(q, rwb->cb);
rwb->min_lat_nsec = wbt_default_latency_nsec(q);
wbt_set_queue_depth(rwb, blk_queue_depth(q));
wbt_set_write_cache(rwb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
wbt_set_queue_depth(q, blk_queue_depth(q));
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
return 0;
}
void wbt_exit(struct request_queue *q)
{
struct rq_wb *rwb = q->rq_wb;
if (rwb) {
blk_stat_remove_callback(q, rwb->cb);
blk_stat_free_callback(rwb->cb);
q->rq_wb = NULL;
kfree(rwb);
}
}

View File

@ -9,6 +9,7 @@
#include <linux/ktime.h>
#include "blk-stat.h"
#include "blk-rq-qos.h"
enum wbt_flags {
WBT_TRACKED = 1, /* write, tracked for throttling */
@ -35,20 +36,12 @@ enum {
WBT_STATE_ON_MANUAL = 2,
};
struct rq_wait {
wait_queue_head_t wait;
atomic_t inflight;
};
struct rq_wb {
/*
* Settings that govern how we throttle
*/
unsigned int wb_background; /* background writeback */
unsigned int wb_normal; /* normal writeback */
unsigned int wb_max; /* max throughput writeback */
int scale_step;
bool scaled_max;
short enable_state; /* WBT_STATE_* */
@ -67,15 +60,20 @@ struct rq_wb {
void *sync_cookie;
unsigned int wc;
unsigned int queue_depth;
unsigned long last_issue; /* last non-throttled issue */
unsigned long last_comp; /* last non-throttled comp */
unsigned long min_lat_nsec;
struct request_queue *queue;
struct rq_qos rqos;
struct rq_wait rq_wait[WBT_NUM_RWQ];
struct rq_depth rq_depth;
};
static inline struct rq_wb *RQWB(struct rq_qos *rqos)
{
return container_of(rqos, struct rq_wb, rqos);
}
static inline unsigned int wbt_inflight(struct rq_wb *rwb)
{
unsigned int i, ret = 0;
@ -86,6 +84,7 @@ static inline unsigned int wbt_inflight(struct rq_wb *rwb)
return ret;
}
#ifdef CONFIG_BLK_WBT
static inline void wbt_track(struct request *rq, enum wbt_flags flags)
@ -93,19 +92,16 @@ static inline void wbt_track(struct request *rq, enum wbt_flags flags)
rq->wbt_flags |= flags;
}
void __wbt_done(struct rq_wb *, enum wbt_flags);
void wbt_done(struct rq_wb *, struct request *);
enum wbt_flags wbt_wait(struct rq_wb *, struct bio *, spinlock_t *);
int wbt_init(struct request_queue *);
void wbt_exit(struct request_queue *);
void wbt_update_limits(struct rq_wb *);
void wbt_requeue(struct rq_wb *, struct request *);
void wbt_issue(struct rq_wb *, struct request *);
void wbt_update_limits(struct request_queue *);
void wbt_disable_default(struct request_queue *);
void wbt_enable_default(struct request_queue *);
void wbt_set_queue_depth(struct rq_wb *, unsigned int);
void wbt_set_write_cache(struct rq_wb *, bool);
u64 wbt_get_min_lat(struct request_queue *q);
void wbt_set_min_lat(struct request_queue *q, u64 val);
void wbt_set_queue_depth(struct request_queue *, unsigned int);
void wbt_set_write_cache(struct request_queue *, bool);
u64 wbt_default_latency_nsec(struct request_queue *);
@ -114,31 +110,11 @@ u64 wbt_default_latency_nsec(struct request_queue *);
static inline void wbt_track(struct request *rq, enum wbt_flags flags)
{
}
static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
{
}
static inline void wbt_done(struct rq_wb *rwb, struct request *rq)
{
}
static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
spinlock_t *lock)
{
return 0;
}
static inline int wbt_init(struct request_queue *q)
{
return -EINVAL;
}
static inline void wbt_exit(struct request_queue *q)
{
}
static inline void wbt_update_limits(struct rq_wb *rwb)
{
}
static inline void wbt_requeue(struct rq_wb *rwb, struct request *rq)
{
}
static inline void wbt_issue(struct rq_wb *rwb, struct request *rq)
static inline void wbt_update_limits(struct request_queue *q)
{
}
static inline void wbt_disable_default(struct request_queue *q)
@ -147,10 +123,17 @@ static inline void wbt_disable_default(struct request_queue *q)
static inline void wbt_enable_default(struct request_queue *q)
{
}
static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
static inline void wbt_set_queue_depth(struct request_queue *q, unsigned int depth)
{
}
static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
{
}
static inline u64 wbt_get_min_lat(struct request_queue *q)
{
return 0;
}
static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
{
}
static inline u64 wbt_default_latency_nsec(struct request_queue *q)

View File

@ -42,7 +42,7 @@ struct bsg_job;
struct blkcg_gq;
struct blk_flush_queue;
struct pr_ops;
struct rq_wb;
struct rq_qos;
struct blk_queue_stats;
struct blk_stat_callback;
@ -443,7 +443,7 @@ struct request_queue {
int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
struct blk_queue_stats *stats;
struct rq_wb *rq_wb;
struct rq_qos *rq_qos;
/*
* If blkcg is not used, @q->root_rl serves all requests. If blkcg