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yaml
---
r: 37527
b: refs/heads/master
c: 9817064
h: refs/heads/master
i:
  37525: 8321c22
  37523: c3c145c
  37519: 4c70666
v: v3
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Jens Axboe authored and Jens Axboe committed Sep 30, 2006
1 parent 16b21fc commit 1f50e53
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Showing 8 changed files with 147 additions and 376 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 4aff5e2333c9a1609662f2091f55c3f6fffdad36
refs/heads/master: 9817064b68fef7e4580c6df1ea597e106b9ff88b
139 changes: 3 additions & 136 deletions trunk/block/as-iosched.c
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,6 @@
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/interrupt.h>

Expand Down Expand Up @@ -95,7 +94,6 @@ struct as_data {

struct as_rq *next_arq[2]; /* next in sort order */
sector_t last_sector[2]; /* last REQ_SYNC & REQ_ASYNC sectors */
struct hlist_head *hash; /* request hash */

unsigned long exit_prob; /* probability a task will exit while
being waited on */
Expand Down Expand Up @@ -161,11 +159,6 @@ struct as_rq {

struct io_context *io_context; /* The submitting task */

/*
* request hash, key is the ending offset (for back merge lookup)
*/
struct hlist_node hash;

/*
* expire fifo
*/
Expand Down Expand Up @@ -272,77 +265,6 @@ static void as_put_io_context(struct as_rq *arq)
put_io_context(arq->io_context);
}

/*
* the back merge hash support functions
*/
static const int as_hash_shift = 6;
#define AS_HASH_BLOCK(sec) ((sec) >> 3)
#define AS_HASH_FN(sec) (hash_long(AS_HASH_BLOCK((sec)), as_hash_shift))
#define AS_HASH_ENTRIES (1 << as_hash_shift)
#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)

static inline void __as_del_arq_hash(struct as_rq *arq)
{
hlist_del_init(&arq->hash);
}

static inline void as_del_arq_hash(struct as_rq *arq)
{
if (!hlist_unhashed(&arq->hash))
__as_del_arq_hash(arq);
}

static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;

BUG_ON(!hlist_unhashed(&arq->hash));

hlist_add_head(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
}

/*
* move hot entry to front of chain
*/
static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;
struct hlist_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];

if (hlist_unhashed(&arq->hash)) {
WARN_ON(1);
return;
}

if (&arq->hash != head->first) {
hlist_del(&arq->hash);
hlist_add_head(&arq->hash, head);
}
}

static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
{
struct hlist_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
struct hlist_node *entry, *next;
struct as_rq *arq;

hlist_for_each_entry_safe(arq, entry, next, hash_list, hash) {
struct request *__rq = arq->request;

BUG_ON(hlist_unhashed(&arq->hash));

if (!rq_mergeable(__rq)) {
as_del_arq_hash(arq);
continue;
}

if (rq_hash_key(__rq) == offset)
return __rq;
}

return NULL;
}

/*
* rb tree support functions
*/
Expand Down Expand Up @@ -1060,7 +982,6 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq)
ad->next_arq[data_dir] = as_find_next_arq(ad, arq);

list_del_init(&arq->fifo);
as_del_arq_hash(arq);
as_del_arq_rb(ad, arq);
}

Expand Down Expand Up @@ -1349,8 +1270,6 @@ static void as_add_request(request_queue_t *q, struct request *rq)
}

as_add_arq_rb(ad, arq);
if (rq_mergeable(arq->request))
as_add_arq_hash(ad, arq);

/*
* set expire time (only used for reads) and add to fifo list
Expand Down Expand Up @@ -1428,55 +1347,24 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
struct as_data *ad = q->elevator->elevator_data;
sector_t rb_key = bio->bi_sector + bio_sectors(bio);
struct request *__rq;
int ret;

/*
* see if the merge hash can satisfy a back merge
*/
__rq = as_find_arq_hash(ad, bio->bi_sector);
if (__rq) {
BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);

if (elv_rq_merge_ok(__rq, bio)) {
ret = ELEVATOR_BACK_MERGE;
goto out;
}
}

/*
* check for front merge
*/
__rq = as_find_arq_rb(ad, rb_key, bio_data_dir(bio));
if (__rq) {
BUG_ON(rb_key != rq_rb_key(__rq));

if (elv_rq_merge_ok(__rq, bio)) {
ret = ELEVATOR_FRONT_MERGE;
goto out;
}
if (__rq && elv_rq_merge_ok(__rq, bio)) {
*req = __rq;
return ELEVATOR_FRONT_MERGE;
}

return ELEVATOR_NO_MERGE;
out:
if (ret) {
if (rq_mergeable(__rq))
as_hot_arq_hash(ad, RQ_DATA(__rq));
}
*req = __rq;
return ret;
}

static void as_merged_request(request_queue_t *q, struct request *req)
{
struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(req);

/*
* hash always needs to be repositioned, key is end sector
*/
as_del_arq_hash(arq);
as_add_arq_hash(ad, arq);

/*
* if the merge was a front merge, we need to reposition request
*/
Expand All @@ -1501,13 +1389,6 @@ static void as_merged_requests(request_queue_t *q, struct request *req,
BUG_ON(!arq);
BUG_ON(!anext);

/*
* reposition arq (this is the merged request) in hash, and in rbtree
* in case of a front merge
*/
as_del_arq_hash(arq);
as_add_arq_hash(ad, arq);

if (rq_rb_key(req) != arq->rb_key) {
as_del_arq_rb(ad, arq);
as_add_arq_rb(ad, arq);
Expand Down Expand Up @@ -1591,7 +1472,6 @@ static int as_set_request(request_queue_t *q, struct request *rq,
arq->request = rq;
arq->state = AS_RQ_PRESCHED;
arq->io_context = NULL;
INIT_HLIST_NODE(&arq->hash);
INIT_LIST_HEAD(&arq->fifo);
rq->elevator_private = arq;
return 0;
Expand Down Expand Up @@ -1628,7 +1508,6 @@ static void as_exit_queue(elevator_t *e)

mempool_destroy(ad->arq_pool);
put_io_context(ad->io_context);
kfree(ad->hash);
kfree(ad);
}

Expand All @@ -1639,7 +1518,6 @@ static void as_exit_queue(elevator_t *e)
static void *as_init_queue(request_queue_t *q, elevator_t *e)
{
struct as_data *ad;
int i;

if (!arq_pool)
return NULL;
Expand All @@ -1651,17 +1529,9 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)

ad->q = q; /* Identify what queue the data belongs to */

ad->hash = kmalloc_node(sizeof(struct hlist_head)*AS_HASH_ENTRIES,
GFP_KERNEL, q->node);
if (!ad->hash) {
kfree(ad);
return NULL;
}

ad->arq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
mempool_free_slab, arq_pool, q->node);
if (!ad->arq_pool) {
kfree(ad->hash);
kfree(ad);
return NULL;
}
Expand All @@ -1672,9 +1542,6 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)
init_timer(&ad->antic_timer);
INIT_WORK(&ad->antic_work, as_work_handler, q);

for (i = 0; i < AS_HASH_ENTRIES; i++)
INIT_HLIST_HEAD(&ad->hash[i]);

INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);
INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
ad->sort_list[REQ_SYNC] = RB_ROOT;
Expand Down
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