[PATCH] iosched: use hlist for request hashtable
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 <mita@miraclelinux.com>
Signed-off-by: Jens Axboe <axboe@suse.de>
block/as-iosched.c | 45 +++++++++++++++++++--------------------------
block/deadline-iosched.c | 39 ++++++++++++++++-----------------------
2 files changed, 35 insertions(+), 49 deletions(-)
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 0c75039..9b13d72 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -96,7 +96,7 @@
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 */
@@ -165,8 +165,7 @@
/*
* 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
@@ -282,17 +281,15 @@
#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);
}
@@ -300,10 +297,9 @@
{
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))]);
}
/*
@@ -312,31 +308,29 @@
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);
@@ -1601,8 +1595,7 @@
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;
@@ -1662,7 +1655,7 @@
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);
@@ -1684,7 +1677,7 @@
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]);
