*
*
- * 30042000 Jens Axboe <axboe@suse.de> :
+ * 30042000 Jens Axboe <axboe@kernel.dk> :
*
* Split the elevator a bit so that it is possible to choose a different
* one or even write a new "plug in". There are three pieces:
#include <linux/compiler.h>
#include <linux/delay.h>
#include <linux/blktrace_api.h>
+#include <linux/hash.h>
#include <asm/uaccess.h>
static DEFINE_SPINLOCK(elv_list_lock);
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) ((rq)->sector + (rq)->nr_sectors)
+#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
+
/*
* can we safely merge with this request?
*/
/*
* same device and no special stuff set, merge is ok
*/
- if (rq->rq_disk == bio->bi_bdev->bd_disk &&
- !rq->waiting && !rq->special)
+ if (rq->rq_disk == bio->bi_bdev->bd_disk && !rq->special)
return 1;
return 0;
static struct elevator_type *elevator_find(const char *name)
{
- struct elevator_type *e = NULL;
+ struct elevator_type *e;
struct list_head *entry;
list_for_each(entry, &elv_list) {
- struct elevator_type *__e;
- __e = list_entry(entry, struct elevator_type, list);
+ e = list_entry(entry, struct elevator_type, list);
- if (!strcmp(__e->elevator_name, name)) {
- e = __e;
- break;
- }
+ if (!strcmp(e->elevator_name, name))
+ return e;
}
- return e;
+ return NULL;
}
static void elevator_put(struct elevator_type *e)
static struct kobj_type elv_ktype;
-static elevator_t *elevator_alloc(struct elevator_type *e)
-{
- elevator_t *eq = kmalloc(sizeof(elevator_t), GFP_KERNEL);
- if (eq) {
- memset(eq, 0, sizeof(*eq));
- eq->ops = &e->ops;
- eq->elevator_type = e;
- kobject_init(&eq->kobj);
- snprintf(eq->kobj.name, KOBJ_NAME_LEN, "%s", "iosched");
- eq->kobj.ktype = &elv_ktype;
- mutex_init(&eq->sysfs_lock);
- } else {
- elevator_put(e);
- }
+static elevator_t *elevator_alloc(request_queue_t *q, struct elevator_type *e)
+{
+ elevator_t *eq;
+ int i;
+
+ eq = kmalloc_node(sizeof(elevator_t), GFP_KERNEL, q->node);
+ if (unlikely(!eq))
+ goto err;
+
+ memset(eq, 0, sizeof(*eq));
+ eq->ops = &e->ops;
+ eq->elevator_type = e;
+ kobject_init(&eq->kobj);
+ snprintf(eq->kobj.name, KOBJ_NAME_LEN, "%s", "iosched");
+ eq->kobj.ktype = &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]);
+
return eq;
+err:
+ kfree(eq);
+ elevator_put(e);
+ return NULL;
}
static void elevator_release(struct kobject *kobj)
{
elevator_t *e = container_of(kobj, elevator_t, kobj);
+
elevator_put(e->elevator_type);
+ kfree(e->hash);
kfree(e);
}
e = elevator_get("noop");
}
- eq = elevator_alloc(e);
+ eq = elevator_alloc(q, e);
if (!eq)
return -ENOMEM;
return ret;
}
+EXPORT_SYMBOL(elevator_init);
+
void elevator_exit(elevator_t *e)
{
mutex_lock(&e->sysfs_lock);
kobject_put(&e->kobj);
}
+EXPORT_SYMBOL(elevator_exit);
+
+static inline void __elv_rqhash_del(struct request *rq)
+{
+ hlist_del_init(&rq->hash);
+}
+
+static void elv_rqhash_del(request_queue_t *q, struct request *rq)
+{
+ if (ELV_ON_HASH(rq))
+ __elv_rqhash_del(rq);
+}
+
+static void elv_rqhash_add(request_queue_t *q, struct request *rq)
+{
+ elevator_t *e = q->elevator;
+
+ BUG_ON(ELV_ON_HASH(rq));
+ hlist_add_head(&rq->hash, &e->hash[ELV_HASH_FN(rq_hash_key(rq))]);
+}
+
+static void elv_rqhash_reposition(request_queue_t *q, struct request *rq)
+{
+ __elv_rqhash_del(rq);
+ elv_rqhash_add(q, rq);
+}
+
+static struct request *elv_rqhash_find(request_queue_t *q, sector_t offset)
+{
+ elevator_t *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) {
+ BUG_ON(!ELV_ON_HASH(rq));
+
+ if (unlikely(!rq_mergeable(rq))) {
+ __elv_rqhash_del(rq);
+ continue;
+ }
+
+ if (rq_hash_key(rq) == offset)
+ return rq;
+ }
+
+ return NULL;
+}
+
+/*
+ * RB-tree support functions for inserting/lookup/removal of requests
+ * in a sorted RB tree.
+ */
+struct request *elv_rb_add(struct rb_root *root, struct request *rq)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ struct request *__rq;
+
+ while (*p) {
+ parent = *p;
+ __rq = rb_entry(parent, struct request, rb_node);
+
+ if (rq->sector < __rq->sector)
+ p = &(*p)->rb_left;
+ else if (rq->sector > __rq->sector)
+ p = &(*p)->rb_right;
+ else
+ return __rq;
+ }
+
+ rb_link_node(&rq->rb_node, parent, p);
+ rb_insert_color(&rq->rb_node, root);
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_add);
+
+void elv_rb_del(struct rb_root *root, struct request *rq)
+{
+ BUG_ON(RB_EMPTY_NODE(&rq->rb_node));
+ rb_erase(&rq->rb_node, root);
+ RB_CLEAR_NODE(&rq->rb_node);
+}
+
+EXPORT_SYMBOL(elv_rb_del);
+
+struct request *elv_rb_find(struct rb_root *root, sector_t sector)
+{
+ struct rb_node *n = root->rb_node;
+ struct request *rq;
+
+ while (n) {
+ rq = rb_entry(n, struct request, rb_node);
+
+ if (sector < rq->sector)
+ n = n->rb_left;
+ else if (sector > rq->sector)
+ n = n->rb_right;
+ else
+ return rq;
+ }
+
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_find);
+
/*
* Insert rq into dispatch queue of q. Queue lock must be held on
- * entry. If sort != 0, rq is sort-inserted; otherwise, rq will be
- * appended to the dispatch queue. To be used by specific elevators.
+ * entry. rq is sort insted into the dispatch queue. To be used by
+ * specific elevators.
*/
void elv_dispatch_sort(request_queue_t *q, struct request *rq)
{
if (q->last_merge == rq)
q->last_merge = NULL;
+
+ elv_rqhash_del(q, rq);
+
q->nr_sorted--;
boundary = q->end_sector;
list_for_each_prev(entry, &q->queue_head) {
struct request *pos = list_entry_rq(entry);
- if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
+ if (pos->cmd_flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
break;
if (rq->sector >= boundary) {
if (pos->sector < boundary)
list_add(&rq->queuelist, entry);
}
+EXPORT_SYMBOL(elv_dispatch_sort);
+
+/*
+ * Insert rq into dispatch queue of q. Queue lock must be held on
+ * entry. rq is added to the back of the dispatch queue. To be used by
+ * specific elevators.
+ */
+void elv_dispatch_add_tail(struct request_queue *q, struct request *rq)
+{
+ if (q->last_merge == rq)
+ q->last_merge = NULL;
+
+ elv_rqhash_del(q, rq);
+
+ q->nr_sorted--;
+
+ q->end_sector = rq_end_sector(rq);
+ q->boundary_rq = rq;
+ list_add_tail(&rq->queuelist, &q->queue_head);
+}
+
+EXPORT_SYMBOL(elv_dispatch_add_tail);
+
int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
elevator_t *e = q->elevator;
+ struct request *__rq;
int ret;
+ /*
+ * First try one-hit cache.
+ */
if (q->last_merge) {
ret = elv_try_merge(q->last_merge, bio);
if (ret != ELEVATOR_NO_MERGE) {
}
}
+ /*
+ * See if our hash lookup can find a potential backmerge.
+ */
+ __rq = elv_rqhash_find(q, bio->bi_sector);
+ if (__rq && elv_rq_merge_ok(__rq, bio)) {
+ *req = __rq;
+ return ELEVATOR_BACK_MERGE;
+ }
+
if (e->ops->elevator_merge_fn)
return e->ops->elevator_merge_fn(q, req, bio);
return ELEVATOR_NO_MERGE;
}
-void elv_merged_request(request_queue_t *q, struct request *rq)
+void elv_merged_request(request_queue_t *q, struct request *rq, int type)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_merged_fn)
- e->ops->elevator_merged_fn(q, rq);
+ e->ops->elevator_merged_fn(q, rq, type);
+
+ if (type == ELEVATOR_BACK_MERGE)
+ elv_rqhash_reposition(q, rq);
q->last_merge = rq;
}
if (e->ops->elevator_merge_req_fn)
e->ops->elevator_merge_req_fn(q, rq, next);
- q->nr_sorted--;
+ elv_rqhash_reposition(q, rq);
+ elv_rqhash_del(q, next);
+
+ q->nr_sorted--;
q->last_merge = rq;
}
e->ops->elevator_deactivate_req_fn(q, rq);
}
- rq->flags &= ~REQ_STARTED;
+ rq->cmd_flags &= ~REQ_STARTED;
elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
}
switch (where) {
case ELEVATOR_INSERT_FRONT:
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
list_add(&rq->queuelist, &q->queue_head);
break;
case ELEVATOR_INSERT_BACK:
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
elv_drain_elevator(q);
list_add_tail(&rq->queuelist, &q->queue_head);
/*
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
- rq->flags |= REQ_SORTED;
+ rq->cmd_flags |= REQ_SORTED;
q->nr_sorted++;
- if (q->last_merge == NULL && rq_mergeable(rq))
- q->last_merge = rq;
+ if (rq_mergeable(rq)) {
+ elv_rqhash_add(q, rq);
+ if (!q->last_merge)
+ q->last_merge = rq;
+ }
+
/*
* Some ioscheds (cfq) run q->request_fn directly, so
* rq cannot be accessed after calling
* insertion; otherwise, requests should be requeued
* in ordseq order.
*/
- rq->flags |= REQ_SOFTBARRIER;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
if (q->ordseq == 0) {
list_add(&rq->queuelist, &q->queue_head);
int plug)
{
if (q->ordcolor)
- rq->flags |= REQ_ORDERED_COLOR;
+ rq->cmd_flags |= REQ_ORDERED_COLOR;
- if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
+ if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
/*
* toggle ordered color
*/
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
- } else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
+ } else if (!(rq->cmd_flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (plug)
elv_insert(q, rq, where);
}
+EXPORT_SYMBOL(__elv_add_request);
+
void elv_add_request(request_queue_t *q, struct request *rq, int where,
int plug)
{
spin_unlock_irqrestore(q->queue_lock, flags);
}
+EXPORT_SYMBOL(elv_add_request);
+
static inline struct request *__elv_next_request(request_queue_t *q)
{
struct request *rq;
int ret;
while ((rq = __elv_next_request(q)) != NULL) {
- if (!(rq->flags & REQ_STARTED)) {
+ if (!(rq->cmd_flags & REQ_STARTED)) {
elevator_t *e = q->elevator;
/*
* it, a request that has been delayed should
* not be passed by new incoming requests
*/
- rq->flags |= REQ_STARTED;
+ rq->cmd_flags |= REQ_STARTED;
blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
}
q->boundary_rq = NULL;
}
- if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn)
+ if ((rq->cmd_flags & REQ_DONTPREP) || !q->prep_rq_fn)
break;
ret = q->prep_rq_fn(q, rq);
nr_bytes = rq->data_len;
blkdev_dequeue_request(rq);
- rq->flags |= REQ_QUIET;
+ rq->cmd_flags |= REQ_QUIET;
end_that_request_chunk(rq, 0, nr_bytes);
end_that_request_last(rq, 0);
} else {
return rq;
}
+EXPORT_SYMBOL(elv_next_request);
+
void elv_dequeue_request(request_queue_t *q, struct request *rq)
{
BUG_ON(list_empty(&rq->queuelist));
+ BUG_ON(ELV_ON_HASH(rq));
list_del_init(&rq->queuelist);
q->in_flight++;
}
+EXPORT_SYMBOL(elv_dequeue_request);
+
int elv_queue_empty(request_queue_t *q)
{
elevator_t *e = q->elevator;
return 1;
}
+EXPORT_SYMBOL(elv_queue_empty);
+
struct request *elv_latter_request(request_queue_t *q, struct request *rq)
{
elevator_t *e = q->elevator;
return NULL;
}
-int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
- gfp_t gfp_mask)
+int elv_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_set_req_fn)
- return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
+ return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
rq->elevator_private = NULL;
return 0;
e->ops->elevator_put_req_fn(q, rq);
}
-int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
+int elv_may_queue(request_queue_t *q, int rw)
{
elevator_t *e = q->elevator;
if (e->ops->elevator_may_queue_fn)
- return e->ops->elevator_may_queue_fn(q, rw, bio);
+ return e->ops->elevator_may_queue_fn(q, rw);
return ELV_MQUEUE_MAY;
}
/*
* Allocate new elevator
*/
- e = elevator_alloc(new_e);
+ e = elevator_alloc(q, new_e);
if (!e)
return 0;
struct list_head *entry;
int len = 0;
- spin_lock_irq(q->queue_lock);
+ spin_lock_irq(&elv_list_lock);
list_for_each(entry, &elv_list) {
struct elevator_type *__e;
else
len += sprintf(name+len, "%s ", __e->elevator_name);
}
- spin_unlock_irq(q->queue_lock);
+ spin_unlock_irq(&elv_list_lock);
len += sprintf(len+name, "\n");
return len;
}
-EXPORT_SYMBOL(elv_dispatch_sort);
-EXPORT_SYMBOL(elv_add_request);
-EXPORT_SYMBOL(__elv_add_request);
-EXPORT_SYMBOL(elv_next_request);
-EXPORT_SYMBOL(elv_dequeue_request);
-EXPORT_SYMBOL(elv_queue_empty);
-EXPORT_SYMBOL(elevator_exit);
-EXPORT_SYMBOL(elevator_init);
+struct request *elv_rb_former_request(request_queue_t *q, struct request *rq)
+{
+ struct rb_node *rbprev = rb_prev(&rq->rb_node);
+
+ if (rbprev)
+ return rb_entry_rq(rbprev);
+
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_former_request);
+
+struct request *elv_rb_latter_request(request_queue_t *q, struct request *rq)
+{
+ struct rb_node *rbnext = rb_next(&rq->rb_node);
+
+ if (rbnext)
+ return rb_entry_rq(rbnext);
+
+ return NULL;
+}
+
+EXPORT_SYMBOL(elv_rb_latter_request);
projects / linux.git / blobdiff