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[PATCH] iosched: use hlist for request hashtable
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Use hlist instead of list_head for request hashtable in deadline-iosched
and as-iosched. It also can remove the flag to know hashed or unhashed.

Signed-off-by: Akinobu Mita <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

 block/as-iosched.c       |   45 +++++++++++++++++++--------------------------
 block/deadline-iosched.c |   39 ++++++++++++++++-----------------------
 2 files changed, 35 insertions(+), 49 deletions(-)
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Akinobu Mita authored and Jens Axboe committed Jun 23, 2006
1 parent 199f4c9 commit bae386f
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Showing 2 changed files with 35 additions and 49 deletions.
45 changes: 19 additions & 26 deletions block/as-iosched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -96,7 +96,7 @@ 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 list_head *hash; /* request hash */
struct hlist_head *hash; /* request hash */

unsigned long exit_prob; /* probability a task will exit while
being waited on */
Expand Down Expand Up @@ -165,8 +165,7 @@ struct as_rq {
/*
* request hash, key is the ending offset (for back merge lookup)
*/
struct list_head hash;
unsigned int on_hash;
struct hlist_node hash;

/*
* expire fifo
Expand Down Expand Up @@ -282,28 +281,25 @@ static const int as_hash_shift = 6;
#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)
#define list_entry_hash(ptr) list_entry((ptr), struct as_rq, hash)

static inline void __as_del_arq_hash(struct as_rq *arq)
{
arq->on_hash = 0;
list_del_init(&arq->hash);
hlist_del_init(&arq->hash);
}

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

arq->on_hash = 1;
list_add(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
hlist_add_head(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
}

/*
Expand All @@ -312,31 +308,29 @@ static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
{
struct request *rq = arq->request;
struct list_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
struct hlist_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];

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

if (arq->hash.prev != head) {
list_del(&arq->hash);
list_add(&arq->hash, head);
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 list_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
struct list_head *entry, *next = hash_list->next;
struct hlist_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
struct hlist_node *entry, *next;
struct as_rq *arq;

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

next = entry->next;

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

if (!rq_mergeable(__rq)) {
as_del_arq_hash(arq);
Expand Down Expand Up @@ -1601,8 +1595,7 @@ 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_LIST_HEAD(&arq->hash);
arq->on_hash = 0;
INIT_HLIST_NODE(&arq->hash);
INIT_LIST_HEAD(&arq->fifo);
rq->elevator_private = arq;
return 0;
Expand Down Expand Up @@ -1662,7 +1655,7 @@ 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 list_head)*AS_HASH_ENTRIES,
ad->hash = kmalloc_node(sizeof(struct hlist_head)*AS_HASH_ENTRIES,
GFP_KERNEL, q->node);
if (!ad->hash) {
kfree(ad);
Expand All @@ -1684,7 +1677,7 @@ static void *as_init_queue(request_queue_t *q, elevator_t *e)
INIT_WORK(&ad->antic_work, as_work_handler, q);

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

INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);
INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
Expand Down
39 changes: 16 additions & 23 deletions block/deadline-iosched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,7 @@ static const int deadline_hash_shift = 5;
#define DL_HASH_FN(sec) (hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift))
#define DL_HASH_ENTRIES (1 << deadline_hash_shift)
#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
#define list_entry_hash(ptr) list_entry((ptr), struct deadline_rq, hash)
#define ON_HASH(drq) (drq)->on_hash
#define ON_HASH(drq) (!hlist_unhashed(&(drq)->hash))

struct deadline_data {
/*
Expand All @@ -48,7 +47,7 @@ struct deadline_data {
* next in sort order. read, write or both are NULL
*/
struct deadline_rq *next_drq[2];
struct list_head *hash; /* request hash */
struct hlist_head *hash; /* request hash */
unsigned int batching; /* number of sequential requests made */
sector_t last_sector; /* head position */
unsigned int starved; /* times reads have starved writes */
Expand Down Expand Up @@ -79,8 +78,7 @@ struct deadline_rq {
/*
* request hash, key is the ending offset (for back merge lookup)
*/
struct list_head hash;
char on_hash;
struct hlist_node hash;

/*
* expire fifo
Expand All @@ -100,8 +98,7 @@ static kmem_cache_t *drq_pool;
*/
static inline void __deadline_del_drq_hash(struct deadline_rq *drq)
{
drq->on_hash = 0;
list_del_init(&drq->hash);
hlist_del_init(&drq->hash);
}

static inline void deadline_del_drq_hash(struct deadline_rq *drq)
Expand All @@ -117,8 +114,7 @@ deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)

BUG_ON(ON_HASH(drq));

drq->on_hash = 1;
list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
hlist_add_head(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
}

/*
Expand All @@ -128,26 +124,24 @@ static inline void
deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
{
struct request *rq = drq->request;
struct list_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))];
struct hlist_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))];

if (ON_HASH(drq) && drq->hash.prev != head) {
list_del(&drq->hash);
list_add(&drq->hash, head);
if (ON_HASH(drq) && &drq->hash != head->first) {
hlist_del(&drq->hash);
hlist_add_head(&drq->hash, head);
}
}

static struct request *
deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
{
struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
struct list_head *entry, *next = hash_list->next;
struct hlist_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
struct hlist_node *entry, *next;
struct deadline_rq *drq;

while ((entry = next) != hash_list) {
struct deadline_rq *drq = list_entry_hash(entry);
hlist_for_each_entry_safe(drq, entry, next, hash_list, hash) {
struct request *__rq = drq->request;

next = entry->next;

BUG_ON(!ON_HASH(drq));

if (!rq_mergeable(__rq)) {
Expand Down Expand Up @@ -625,7 +619,7 @@ static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
return NULL;
memset(dd, 0, sizeof(*dd));

dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES,
dd->hash = kmalloc_node(sizeof(struct hlist_head)*DL_HASH_ENTRIES,
GFP_KERNEL, q->node);
if (!dd->hash) {
kfree(dd);
Expand All @@ -641,7 +635,7 @@ static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
}

for (i = 0; i < DL_HASH_ENTRIES; i++)
INIT_LIST_HEAD(&dd->hash[i]);
INIT_HLIST_HEAD(&dd->hash[i]);

INIT_LIST_HEAD(&dd->fifo_list[READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
Expand Down Expand Up @@ -677,8 +671,7 @@ deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
RB_CLEAR(&drq->rb_node);
drq->request = rq;

INIT_LIST_HEAD(&drq->hash);
drq->on_hash = 0;
INIT_HLIST_NODE(&drq->hash);

INIT_LIST_HEAD(&drq->fifo);

Expand Down

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