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authorJens Axboe <axboe@suse.de>2006-07-18 21:06:01 +0200
committerJens Axboe <axboe@nelson.home.kernel.dk>2006-09-30 20:26:57 +0200
commite37f346e347e5035c80760df2be0fcb2824f6c16 (patch)
tree9bd354f831005f04c1c33182607cf61e8fcc09a0 /block/as-iosched.c
parent2e662b65f05d550b6799ed6bfa9963b82279e6b7 (diff)
downloadlinux-2.6.34-ux500-e37f346e347e5035c80760df2be0fcb2824f6c16.tar.gz
[PATCH] as-iosched: migrate to using the elevator rb functions
This removes the rbtree handling from AS. Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Nick Piggin <npiggin@suse.de>
Diffstat (limited to 'block/as-iosched.c')
-rw-r--r--block/as-iosched.c180
1 files changed, 29 insertions, 151 deletions
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 9d0f15a54c6..134545b544c 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -149,12 +149,6 @@ enum arq_state {
};
struct as_rq {
- /*
- * rbtree index, key is the starting offset
- */
- struct rb_node rb_node;
- sector_t rb_key;
-
struct request *request;
struct io_context *io_context; /* The submitting task */
@@ -268,101 +262,22 @@ static void as_put_io_context(struct as_rq *arq)
/*
* rb tree support functions
*/
-#define rb_entry_arq(node) rb_entry((node), struct as_rq, rb_node)
#define ARQ_RB_ROOT(ad, arq) (&(ad)->sort_list[(arq)->is_sync])
-#define rq_rb_key(rq) (rq)->sector
-
-/*
- * as_find_first_arq finds the first (lowest sector numbered) request
- * for the specified data_dir. Used to sweep back to the start of the disk
- * (1-way elevator) after we process the last (highest sector) request.
- */
-static struct as_rq *as_find_first_arq(struct as_data *ad, int data_dir)
-{
- struct rb_node *n = ad->sort_list[data_dir].rb_node;
-
- if (n == NULL)
- return NULL;
-
- for (;;) {
- if (n->rb_left == NULL)
- return rb_entry_arq(n);
-
- n = n->rb_left;
- }
-}
-
-/*
- * Add the request to the rb tree if it is unique. If there is an alias (an
- * existing request against the same sector), which can happen when using
- * direct IO, then return the alias.
- */
-static struct as_rq *__as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
- struct rb_node **p = &ARQ_RB_ROOT(ad, arq)->rb_node;
- struct rb_node *parent = NULL;
- struct as_rq *__arq;
- struct request *rq = arq->request;
-
- arq->rb_key = rq_rb_key(rq);
-
- while (*p) {
- parent = *p;
- __arq = rb_entry_arq(parent);
-
- if (arq->rb_key < __arq->rb_key)
- p = &(*p)->rb_left;
- else if (arq->rb_key > __arq->rb_key)
- p = &(*p)->rb_right;
- else
- return __arq;
- }
-
- rb_link_node(&arq->rb_node, parent, p);
- rb_insert_color(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
- return NULL;
-}
-
-static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
+static void as_add_arq_rb(struct as_data *ad, struct request *rq)
{
- struct as_rq *alias;
+ struct as_rq *arq = RQ_DATA(rq);
+ struct request *alias;
- while ((unlikely(alias = __as_add_arq_rb(ad, arq)))) {
- as_move_to_dispatch(ad, alias);
+ while ((unlikely(alias = elv_rb_add(ARQ_RB_ROOT(ad, arq), rq)))) {
+ as_move_to_dispatch(ad, RQ_DATA(alias));
as_antic_stop(ad);
}
}
-static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
- if (RB_EMPTY_NODE(&arq->rb_node)) {
- WARN_ON(1);
- return;
- }
-
- rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
- RB_CLEAR_NODE(&arq->rb_node);
-}
-
-static struct request *
-as_find_arq_rb(struct as_data *ad, sector_t sector, int data_dir)
+static inline void as_del_arq_rb(struct as_data *ad, struct request *rq)
{
- struct rb_node *n = ad->sort_list[data_dir].rb_node;
- struct as_rq *arq;
-
- while (n) {
- arq = rb_entry_arq(n);
-
- if (sector < arq->rb_key)
- n = n->rb_left;
- else if (sector > arq->rb_key)
- n = n->rb_right;
- else
- return arq->request;
- }
-
- return NULL;
+ elv_rb_del(ARQ_RB_ROOT(ad, RQ_DATA(rq)), rq);
}
/*
@@ -455,32 +370,29 @@ as_choose_req(struct as_data *ad, struct as_rq *arq1, struct as_rq *arq2)
* this with as_choose_req form the basis for how the scheduler chooses
* what request to process next. Anticipation works on top of this.
*/
-static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last)
+static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *arq)
{
- const int data_dir = last->is_sync;
- struct as_rq *ret;
+ struct request *last = arq->request;
struct rb_node *rbnext = rb_next(&last->rb_node);
struct rb_node *rbprev = rb_prev(&last->rb_node);
- struct as_rq *arq_next, *arq_prev;
+ struct as_rq *next = NULL, *prev = NULL;
- BUG_ON(!RB_EMPTY_NODE(&last->rb_node));
+ BUG_ON(RB_EMPTY_NODE(&last->rb_node));
if (rbprev)
- arq_prev = rb_entry_arq(rbprev);
- else
- arq_prev = NULL;
+ prev = RQ_DATA(rb_entry_rq(rbprev));
if (rbnext)
- arq_next = rb_entry_arq(rbnext);
+ next = RQ_DATA(rb_entry_rq(rbnext));
else {
- arq_next = as_find_first_arq(ad, data_dir);
- if (arq_next == last)
- arq_next = NULL;
- }
+ const int data_dir = arq->is_sync;
- ret = as_choose_req(ad, arq_next, arq_prev);
+ rbnext = rb_first(&ad->sort_list[data_dir]);
+ if (rbnext && rbnext != &last->rb_node)
+ next = RQ_DATA(rb_entry_rq(rbnext));
+ }
- return ret;
+ return as_choose_req(ad, next, prev);
}
/*
@@ -982,7 +894,7 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq)
ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
list_del_init(&arq->fifo);
- as_del_arq_rb(ad, arq);
+ as_del_arq_rb(ad, rq);
}
/*
@@ -1039,7 +951,7 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
struct request *rq = arq->request;
const int data_dir = arq->is_sync;
- BUG_ON(RB_EMPTY_NODE(&arq->rb_node));
+ BUG_ON(RB_EMPTY_NODE(&rq->rb_node));
as_antic_stop(ad);
ad->antic_status = ANTIC_OFF;
@@ -1269,7 +1181,7 @@ static void as_add_request(request_queue_t *q, struct request *rq)
atomic_inc(&arq->io_context->aic->nr_queued);
}
- as_add_arq_rb(ad, arq);
+ as_add_arq_rb(ad, rq);
/*
* set expire time (only used for reads) and add to fifo list
@@ -1315,32 +1227,6 @@ static int as_queue_empty(request_queue_t *q)
&& list_empty(&ad->fifo_list[REQ_SYNC]);
}
-static struct request *as_former_request(request_queue_t *q,
- struct request *rq)
-{
- struct as_rq *arq = RQ_DATA(rq);
- struct rb_node *rbprev = rb_prev(&arq->rb_node);
- struct request *ret = NULL;
-
- if (rbprev)
- ret = rb_entry_arq(rbprev)->request;
-
- return ret;
-}
-
-static struct request *as_latter_request(request_queue_t *q,
- struct request *rq)
-{
- struct as_rq *arq = RQ_DATA(rq);
- struct rb_node *rbnext = rb_next(&arq->rb_node);
- struct request *ret = NULL;
-
- if (rbnext)
- ret = rb_entry_arq(rbnext)->request;
-
- return ret;
-}
-
static int
as_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
@@ -1351,7 +1237,7 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
/*
* check for front merge
*/
- __rq = as_find_arq_rb(ad, rb_key, bio_data_dir(bio));
+ __rq = elv_rb_find(&ad->sort_list[bio_data_dir(bio)], rb_key);
if (__rq && elv_rq_merge_ok(__rq, bio)) {
*req = __rq;
return ELEVATOR_FRONT_MERGE;
@@ -1360,17 +1246,16 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio)
return ELEVATOR_NO_MERGE;
}
-static void as_merged_request(request_queue_t *q, struct request *req)
+static void as_merged_request(request_queue_t *q, struct request *req, int type)
{
struct as_data *ad = q->elevator->elevator_data;
- struct as_rq *arq = RQ_DATA(req);
/*
* if the merge was a front merge, we need to reposition request
*/
- if (rq_rb_key(req) != arq->rb_key) {
- as_del_arq_rb(ad, arq);
- as_add_arq_rb(ad, arq);
+ if (type == ELEVATOR_FRONT_MERGE) {
+ as_del_arq_rb(ad, req);
+ as_add_arq_rb(ad, req);
/*
* Note! At this stage of this and the next function, our next
* request may not be optimal - eg the request may have "grown"
@@ -1382,18 +1267,12 @@ static void as_merged_request(request_queue_t *q, struct request *req)
static void as_merged_requests(request_queue_t *q, struct request *req,
struct request *next)
{
- struct as_data *ad = q->elevator->elevator_data;
struct as_rq *arq = RQ_DATA(req);
struct as_rq *anext = RQ_DATA(next);
BUG_ON(!arq);
BUG_ON(!anext);
- if (rq_rb_key(req) != arq->rb_key) {
- as_del_arq_rb(ad, arq);
- as_add_arq_rb(ad, arq);
- }
-
/*
* if anext expires before arq, assign its expire time to arq
* and move into anext position (anext will be deleted) in fifo
@@ -1468,7 +1347,6 @@ static int as_set_request(request_queue_t *q, struct request *rq,
if (arq) {
memset(arq, 0, sizeof(*arq));
- RB_CLEAR_NODE(&arq->rb_node);
arq->request = rq;
arq->state = AS_RQ_PRESCHED;
arq->io_context = NULL;
@@ -1654,8 +1532,8 @@ static struct elevator_type iosched_as = {
.elevator_deactivate_req_fn = as_deactivate_request,
.elevator_queue_empty_fn = as_queue_empty,
.elevator_completed_req_fn = as_completed_request,
- .elevator_former_req_fn = as_former_request,
- .elevator_latter_req_fn = as_latter_request,
+ .elevator_former_req_fn = elv_rb_former_request,
+ .elevator_latter_req_fn = elv_rb_latter_request,
.elevator_set_req_fn = as_set_request,
.elevator_put_req_fn = as_put_request,
.elevator_may_queue_fn = as_may_queue,