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authorSasha Levin <sasha.levin@oracle.com>2012-12-17 10:01:27 -0500
committerJens Axboe <axboe@kernel.dk>2013-01-11 14:43:13 +0100
commit242d98f077ac0ab80920219769eb095503b93f61 (patch)
treedf4bd59a6db181b796ff8687339e4335e2c59104
parent9931faca02c604c22335f5a935a501bb2ace6e20 (diff)
downloadop-kernel-dev-242d98f077ac0ab80920219769eb095503b93f61.zip
op-kernel-dev-242d98f077ac0ab80920219769eb095503b93f61.tar.gz
block,elevator: use new hashtable implementation
Switch elevator to use the new hashtable implementation. This reduces the amount of generic unrelated code in the elevator. This also removes the dymanic allocation of the hash table. The size of the table is constant so there's no point in paying the price of an extra dereference when accessing it. This patch depends on d9b482c ("hashtable: introduce a small and naive hashtable") which was merged in v3.6. Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk.h2
-rw-r--r--block/elevator.c23
-rw-r--r--include/linux/elevator.h5
3 files changed, 9 insertions, 21 deletions
diff --git a/block/blk.h b/block/blk.h
index 47fdfdd..e837b8f 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -61,7 +61,7 @@ static inline void blk_clear_rq_complete(struct request *rq)
/*
* Internal elevator interface
*/
-#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
+#define ELV_ON_HASH(rq) hash_hashed(&(rq)->hash)
void blk_insert_flush(struct request *rq);
void blk_abort_flushes(struct request_queue *q);
diff --git a/block/elevator.c b/block/elevator.c
index 9edba1b..11683bb 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -46,11 +46,6 @@ static LIST_HEAD(elv_list);
/*
* Merge hash stuff.
*/
-static const int elv_hash_shift = 6;
-#define ELV_HASH_BLOCK(sec) ((sec) >> 3)
-#define ELV_HASH_FN(sec) \
- (hash_long(ELV_HASH_BLOCK((sec)), elv_hash_shift))
-#define ELV_HASH_ENTRIES (1 << elv_hash_shift)
#define rq_hash_key(rq) (blk_rq_pos(rq) + blk_rq_sectors(rq))
/*
@@ -142,7 +137,6 @@ static struct elevator_queue *elevator_alloc(struct request_queue *q,
struct elevator_type *e)
{
struct elevator_queue *eq;
- int i;
eq = kmalloc_node(sizeof(*eq), GFP_KERNEL | __GFP_ZERO, q->node);
if (unlikely(!eq))
@@ -151,14 +145,7 @@ static struct elevator_queue *elevator_alloc(struct request_queue *q,
eq->type = e;
kobject_init(&eq->kobj, &elv_ktype);
mutex_init(&eq->sysfs_lock);
-
- eq->hash = kmalloc_node(sizeof(struct hlist_head) * ELV_HASH_ENTRIES,
- GFP_KERNEL, q->node);
- if (!eq->hash)
- goto err;
-
- for (i = 0; i < ELV_HASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&eq->hash[i]);
+ hash_init(eq->hash);
return eq;
err:
@@ -173,7 +160,6 @@ static void elevator_release(struct kobject *kobj)
e = container_of(kobj, struct elevator_queue, kobj);
elevator_put(e->type);
- kfree(e->hash);
kfree(e);
}
@@ -240,7 +226,7 @@ EXPORT_SYMBOL(elevator_exit);
static inline void __elv_rqhash_del(struct request *rq)
{
- hlist_del_init(&rq->hash);
+ hash_del(&rq->hash);
}
static void elv_rqhash_del(struct request_queue *q, struct request *rq)
@@ -254,7 +240,7 @@ static void elv_rqhash_add(struct request_queue *q, struct request *rq)
struct elevator_queue *e = q->elevator;
BUG_ON(ELV_ON_HASH(rq));
- hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]);
+ hash_add(e->hash, &rq->hash, rq_hash_key(rq));
}
static void elv_rqhash_reposition(struct request_queue *q, struct request *rq)
@@ -266,11 +252,10 @@ static void elv_rqhash_reposition(struct request_queue *q, struct request *rq)
static struct request *elv_rqhash_find(struct request_queue *q, sector_t offset)
{
struct elevator_queue *e = q->elevator;
- struct hlist_head *hash_list = &e->hash[ELV_HASH_FN(offset)];
struct hlist_node *entry, *next;
struct request *rq;
- hlist_for_each_entry_safe(rq, entry, next, hash_list, hash) {
+ hash_for_each_possible_safe(e->hash, rq, entry, next, hash, offset) {
BUG_ON(!ELV_ON_HASH(rq));
if (unlikely(!rq_mergeable(rq))) {
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index c03af76..7c5a7c9 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -2,6 +2,7 @@
#define _LINUX_ELEVATOR_H
#include <linux/percpu.h>
+#include <linux/hashtable.h>
#ifdef CONFIG_BLOCK
@@ -96,6 +97,8 @@ struct elevator_type
struct list_head list;
};
+#define ELV_HASH_BITS 6
+
/*
* each queue has an elevator_queue associated with it
*/
@@ -105,8 +108,8 @@ struct elevator_queue
void *elevator_data;
struct kobject kobj;
struct mutex sysfs_lock;
- struct hlist_head *hash;
unsigned int registered:1;
+ DECLARE_HASHTABLE(hash, ELV_HASH_BITS);
};
/*
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