diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/as-iosched.c | 180 |
1 files changed, 29 insertions, 151 deletions
diff --git a/block/as-iosched.c b/block/as-iosched.c index 9d0f15a..134545b 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, |
