[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 (file)
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -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 */
@@ -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
@@ -282,17 +281,15 @@ 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);
 }
 
@@ -300,10 +297,9 @@ 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))]);
 }
 
 /*
@@ -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);
@@ -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;
@@ -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);
@@ -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]);

diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index c94de8e..e5bccaa 100644 (file)
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -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 {
        /*
@@ -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 */
@@ -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
@@ -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)
@@ -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))]);
 }
 
 /*
@@ -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)) {
@@ -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);
@@ -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]);
@@ -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);