X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=block%2Fdeadline-iosched.c;h=87ca02ac84cb1d5a6f77f5377c6ec8f4e7492d55;hb=a5b4860b973bb7a306562d8715ba8538a584537d;hp=c7ca9f0b64989cdda8a16a56593fd52f2a251470;hpb=71bc7bf045262e82c645cad48fd56dd17e75344e;p=pandora-kernel.git diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c index c7ca9f0b6498..87ca02ac84cb 100644 --- a/block/deadline-iosched.c +++ b/block/deadline-iosched.c @@ -1,7 +1,7 @@ /* * Deadline i/o scheduler. * - * Copyright (C) 2002 Jens Axboe + * Copyright (C) 2002 Jens Axboe */ #include #include @@ -12,7 +12,6 @@ #include #include #include -#include #include /* @@ -24,13 +23,6 @@ static const int writes_starved = 2; /* max times reads can starve a write */ static const int fifo_batch = 16; /* # of sequential requests treated as one by the above parameters. For throughput. */ -static const int deadline_hash_shift = 5; -#define DL_HASH_BLOCK(sec) ((sec) >> 3) -#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 ON_HASH(drq) (!hlist_unhashed(&(drq)->hash)) - struct deadline_data { /* * run time data @@ -45,8 +37,7 @@ struct deadline_data { /* * next in sort order. read, write or both are NULL */ - struct deadline_rq *next_drq[2]; - struct hlist_head *hash; /* request hash */ + struct request *next_rq[2]; unsigned int batching; /* number of sequential requests made */ sector_t last_sector; /* head position */ unsigned int starved; /* times reads have starved writes */ @@ -58,240 +49,69 @@ struct deadline_data { int fifo_batch; int writes_starved; int front_merges; - - mempool_t *drq_pool; }; -/* - * pre-request data. - */ -struct deadline_rq { - /* - * rbtree index, key is the starting offset - */ - struct rb_node rb_node; - sector_t rb_key; - - struct request *request; - - /* - * request hash, key is the ending offset (for back merge lookup) - */ - struct hlist_node hash; - - /* - * expire fifo - */ - struct list_head fifo; - unsigned long expires; -}; - -static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq); - -static kmem_cache_t *drq_pool; - -#define RQ_DATA(rq) ((struct deadline_rq *) (rq)->elevator_private) +static void deadline_move_request(struct deadline_data *, struct request *); -/* - * the back merge hash support functions - */ -static inline void __deadline_del_drq_hash(struct deadline_rq *drq) -{ - hlist_del_init(&drq->hash); -} - -static inline void deadline_del_drq_hash(struct deadline_rq *drq) -{ - if (ON_HASH(drq)) - __deadline_del_drq_hash(drq); -} - -static inline void -deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct request *rq = drq->request; - - BUG_ON(ON_HASH(drq)); - - hlist_add_head(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]); -} - -/* - * move hot entry to front of chain - */ -static inline void -deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct request *rq = drq->request; - struct hlist_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))]; - - 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 hlist_head *hash_list = &dd->hash[DL_HASH_FN(offset)]; - struct hlist_node *entry, *next; - struct deadline_rq *drq; - - hlist_for_each_entry_safe(drq, entry, next, hash_list, hash) { - struct request *__rq = drq->request; - - BUG_ON(!ON_HASH(drq)); - - if (!rq_mergeable(__rq)) { - __deadline_del_drq_hash(drq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - -/* - * rb tree support functions - */ -#define rb_entry_drq(node) rb_entry((node), struct deadline_rq, rb_node) -#define DRQ_RB_ROOT(dd, drq) (&(dd)->sort_list[rq_data_dir((drq)->request)]) -#define rq_rb_key(rq) (rq)->sector - -static struct deadline_rq * -__deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) -{ - struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node; - struct rb_node *parent = NULL; - struct deadline_rq *__drq; - - while (*p) { - parent = *p; - __drq = rb_entry_drq(parent); - - if (drq->rb_key < __drq->rb_key) - p = &(*p)->rb_left; - else if (drq->rb_key > __drq->rb_key) - p = &(*p)->rb_right; - else - return __drq; - } - - rb_link_node(&drq->rb_node, parent, p); - return NULL; -} +#define RQ_RB_ROOT(dd, rq) (&(dd)->sort_list[rq_data_dir((rq))]) static void -deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) +deadline_add_rq_rb(struct deadline_data *dd, struct request *rq) { - struct deadline_rq *__alias; - - drq->rb_key = rq_rb_key(drq->request); + struct rb_root *root = RQ_RB_ROOT(dd, rq); + struct request *__alias; retry: - __alias = __deadline_add_drq_rb(dd, drq); - if (!__alias) { - rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); - return; + __alias = elv_rb_add(root, rq); + if (unlikely(__alias)) { + deadline_move_request(dd, __alias); + goto retry; } - - deadline_move_request(dd, __alias); - goto retry; } static inline void -deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) +deadline_del_rq_rb(struct deadline_data *dd, struct request *rq) { - const int data_dir = rq_data_dir(drq->request); + const int data_dir = rq_data_dir(rq); - if (dd->next_drq[data_dir] == drq) { - struct rb_node *rbnext = rb_next(&drq->rb_node); + if (dd->next_rq[data_dir] == rq) { + struct rb_node *rbnext = rb_next(&rq->rb_node); - dd->next_drq[data_dir] = NULL; + dd->next_rq[data_dir] = NULL; if (rbnext) - dd->next_drq[data_dir] = rb_entry_drq(rbnext); - } - - BUG_ON(!RB_EMPTY_NODE(&drq->rb_node)); - rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); - RB_CLEAR_NODE(&drq->rb_node); -} - -static struct request * -deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir) -{ - struct rb_node *n = dd->sort_list[data_dir].rb_node; - struct deadline_rq *drq; - - while (n) { - drq = rb_entry_drq(n); - - if (sector < drq->rb_key) - n = n->rb_left; - else if (sector > drq->rb_key) - n = n->rb_right; - else - return drq->request; + dd->next_rq[data_dir] = rb_entry_rq(rbnext); } - return NULL; + elv_rb_del(RQ_RB_ROOT(dd, rq), rq); } /* - * deadline_find_first_drq 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 deadline_rq * -deadline_find_first_drq(struct deadline_data *dd, int data_dir) -{ - struct rb_node *n = dd->sort_list[data_dir].rb_node; - - for (;;) { - if (n->rb_left == NULL) - return rb_entry_drq(n); - - n = n->rb_left; - } -} - -/* - * add drq to rbtree and fifo + * add rq to rbtree and fifo */ static void deadline_add_request(struct request_queue *q, struct request *rq) { struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(rq); + const int data_dir = rq_data_dir(rq); - const int data_dir = rq_data_dir(drq->request); + deadline_add_rq_rb(dd, rq); - deadline_add_drq_rb(dd, drq); /* * set expire time (only used for reads) and add to fifo list */ - drq->expires = jiffies + dd->fifo_expire[data_dir]; - list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]); - - if (rq_mergeable(rq)) - deadline_add_drq_hash(dd, drq); + rq_set_fifo_time(rq, jiffies + dd->fifo_expire[data_dir]); + list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]); } /* - * remove rq from rbtree, fifo, and hash + * remove rq from rbtree and fifo. */ static void deadline_remove_request(request_queue_t *q, struct request *rq) { - struct deadline_rq *drq = RQ_DATA(rq); struct deadline_data *dd = q->elevator->elevator_data; - list_del_init(&drq->fifo); - deadline_del_drq_rb(dd, drq); - deadline_del_drq_hash(drq); + rq_fifo_clear(rq); + deadline_del_rq_rb(dd, rq); } static int @@ -301,28 +121,15 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) struct request *__rq; int ret; - /* - * see if the merge hash can satisfy a back merge - */ - __rq = deadline_find_drq_hash(dd, bio->bi_sector); - if (__rq) { - BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector); - - if (elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } - } - /* * check for front merge */ if (dd->front_merges) { - sector_t rb_key = bio->bi_sector + bio_sectors(bio); + sector_t sector = bio->bi_sector + bio_sectors(bio); - __rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio)); + __rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector); if (__rq) { - BUG_ON(rb_key != rq_rb_key(__rq)); + BUG_ON(sector != __rq->sector); if (elv_rq_merge_ok(__rq, bio)) { ret = ELEVATOR_FRONT_MERGE; @@ -333,29 +140,21 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; out: - if (ret) - deadline_hot_drq_hash(dd, RQ_DATA(__rq)); *req = __rq; return ret; } -static void deadline_merged_request(request_queue_t *q, struct request *req) +static void deadline_merged_request(request_queue_t *q, struct request *req, + int type) { struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(req); - - /* - * hash always needs to be repositioned, key is end sector - */ - deadline_del_drq_hash(drq); - deadline_add_drq_hash(dd, drq); /* * if the merge was a front merge, we need to reposition request */ - if (rq_rb_key(req) != drq->rb_key) { - deadline_del_drq_rb(dd, drq); - deadline_add_drq_rb(dd, drq); + if (type == ELEVATOR_FRONT_MERGE) { + elv_rb_del(RQ_RB_ROOT(dd, req), req); + deadline_add_rq_rb(dd, req); } } @@ -363,33 +162,14 @@ static void deadline_merged_requests(request_queue_t *q, struct request *req, struct request *next) { - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(req); - struct deadline_rq *dnext = RQ_DATA(next); - - BUG_ON(!drq); - BUG_ON(!dnext); - /* - * reposition drq (this is the merged request) in hash, and in rbtree - * in case of a front merge + * if next expires before rq, assign its expire time to rq + * and move into next position (next will be deleted) in fifo */ - deadline_del_drq_hash(drq); - deadline_add_drq_hash(dd, drq); - - if (rq_rb_key(req) != drq->rb_key) { - deadline_del_drq_rb(dd, drq); - deadline_add_drq_rb(dd, drq); - } - - /* - * if dnext expires before drq, assign its expire time to drq - * and move into dnext position (dnext will be deleted) in fifo - */ - if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) { - if (time_before(dnext->expires, drq->expires)) { - list_move(&drq->fifo, &dnext->fifo); - drq->expires = dnext->expires; + if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) { + if (time_before(rq_fifo_time(next), rq_fifo_time(req))) { + list_move(&req->queuelist, &next->queuelist); + rq_set_fifo_time(req, rq_fifo_time(next)); } } @@ -403,52 +183,50 @@ deadline_merged_requests(request_queue_t *q, struct request *req, * move request from sort list to dispatch queue. */ static inline void -deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq) +deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq) { - request_queue_t *q = drq->request->q; + request_queue_t *q = rq->q; - deadline_remove_request(q, drq->request); - elv_dispatch_add_tail(q, drq->request); + deadline_remove_request(q, rq); + elv_dispatch_add_tail(q, rq); } /* * move an entry to dispatch queue */ static void -deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq) +deadline_move_request(struct deadline_data *dd, struct request *rq) { - const int data_dir = rq_data_dir(drq->request); - struct rb_node *rbnext = rb_next(&drq->rb_node); + const int data_dir = rq_data_dir(rq); + struct rb_node *rbnext = rb_next(&rq->rb_node); - dd->next_drq[READ] = NULL; - dd->next_drq[WRITE] = NULL; + dd->next_rq[READ] = NULL; + dd->next_rq[WRITE] = NULL; if (rbnext) - dd->next_drq[data_dir] = rb_entry_drq(rbnext); + dd->next_rq[data_dir] = rb_entry_rq(rbnext); - dd->last_sector = drq->request->sector + drq->request->nr_sectors; + dd->last_sector = rq->sector + rq->nr_sectors; /* * take it off the sort and fifo list, move * to dispatch queue */ - deadline_move_to_dispatch(dd, drq); + deadline_move_to_dispatch(dd, rq); } -#define list_entry_fifo(ptr) list_entry((ptr), struct deadline_rq, fifo) - /* * deadline_check_fifo returns 0 if there are no expired reads on the fifo, * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir]) */ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) { - struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next); + struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next); /* - * drq is expired! + * rq is expired! */ - if (time_after(jiffies, drq->expires)) + if (time_after(jiffies, rq_fifo_time(rq))) return 1; return 0; @@ -463,21 +241,21 @@ static int deadline_dispatch_requests(request_queue_t *q, int force) struct deadline_data *dd = q->elevator->elevator_data; const int reads = !list_empty(&dd->fifo_list[READ]); const int writes = !list_empty(&dd->fifo_list[WRITE]); - struct deadline_rq *drq; + struct request *rq; int data_dir; /* * batches are currently reads XOR writes */ - if (dd->next_drq[WRITE]) - drq = dd->next_drq[WRITE]; + if (dd->next_rq[WRITE]) + rq = dd->next_rq[WRITE]; else - drq = dd->next_drq[READ]; + rq = dd->next_rq[READ]; - if (drq) { + if (rq) { /* we have a "next request" */ - if (dd->last_sector != drq->request->sector) + if (dd->last_sector != rq->sector) /* end the batch on a non sequential request */ dd->batching += dd->fifo_batch; @@ -526,30 +304,33 @@ dispatch_find_request: if (deadline_check_fifo(dd, data_dir)) { /* An expired request exists - satisfy it */ dd->batching = 0; - drq = list_entry_fifo(dd->fifo_list[data_dir].next); + rq = rq_entry_fifo(dd->fifo_list[data_dir].next); - } else if (dd->next_drq[data_dir]) { + } else if (dd->next_rq[data_dir]) { /* * The last req was the same dir and we have a next request in * sort order. No expired requests so continue on from here. */ - drq = dd->next_drq[data_dir]; + rq = dd->next_rq[data_dir]; } else { + struct rb_node *node; /* * The last req was the other direction or we have run out of * higher-sectored requests. Go back to the lowest sectored * request (1 way elevator) and start a new batch. */ dd->batching = 0; - drq = deadline_find_first_drq(dd, data_dir); + node = rb_first(&dd->sort_list[data_dir]); + if (node) + rq = rb_entry_rq(node); } dispatch_request: /* - * drq is the selected appropriate request. + * rq is the selected appropriate request. */ dd->batching++; - deadline_move_request(dd, drq); + deadline_move_request(dd, rq); return 1; } @@ -562,30 +343,6 @@ static int deadline_queue_empty(request_queue_t *q) && list_empty(&dd->fifo_list[READ]); } -static struct request * -deadline_former_request(request_queue_t *q, struct request *rq) -{ - struct deadline_rq *drq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&drq->rb_node); - - if (rbprev) - return rb_entry_drq(rbprev)->request; - - return NULL; -} - -static struct request * -deadline_latter_request(request_queue_t *q, struct request *rq) -{ - struct deadline_rq *drq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&drq->rb_node); - - if (rbnext) - return rb_entry_drq(rbnext)->request; - - return NULL; -} - static void deadline_exit_queue(elevator_t *e) { struct deadline_data *dd = e->elevator_data; @@ -593,45 +350,19 @@ static void deadline_exit_queue(elevator_t *e) BUG_ON(!list_empty(&dd->fifo_list[READ])); BUG_ON(!list_empty(&dd->fifo_list[WRITE])); - mempool_destroy(dd->drq_pool); - kfree(dd->hash); kfree(dd); } /* - * initialize elevator private data (deadline_data), and alloc a drq for - * each request on the free lists + * initialize elevator private data (deadline_data). */ -static void *deadline_init_queue(request_queue_t *q, elevator_t *e) +static void *deadline_init_queue(request_queue_t *q) { struct deadline_data *dd; - int i; - - if (!drq_pool) - return NULL; - dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node); + dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node); if (!dd) return NULL; - memset(dd, 0, sizeof(*dd)); - - dd->hash = kmalloc_node(sizeof(struct hlist_head)*DL_HASH_ENTRIES, - GFP_KERNEL, q->node); - if (!dd->hash) { - kfree(dd); - return NULL; - } - - dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab, - mempool_free_slab, drq_pool, q->node); - if (!dd->drq_pool) { - kfree(dd->hash); - kfree(dd); - return NULL; - } - - for (i = 0; i < DL_HASH_ENTRIES; i++) - INIT_HLIST_HEAD(&dd->hash[i]); INIT_LIST_HEAD(&dd->fifo_list[READ]); INIT_LIST_HEAD(&dd->fifo_list[WRITE]); @@ -645,39 +376,6 @@ static void *deadline_init_queue(request_queue_t *q, elevator_t *e) return dd; } -static void deadline_put_request(request_queue_t *q, struct request *rq) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq = RQ_DATA(rq); - - mempool_free(drq, dd->drq_pool); - rq->elevator_private = NULL; -} - -static int -deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct deadline_rq *drq; - - drq = mempool_alloc(dd->drq_pool, gfp_mask); - if (drq) { - memset(drq, 0, sizeof(*drq)); - RB_CLEAR_NODE(&drq->rb_node); - drq->request = rq; - - INIT_HLIST_NODE(&drq->hash); - - INIT_LIST_HEAD(&drq->fifo); - - rq->elevator_private = drq; - return 0; - } - - return 1; -} - /* * sysfs parts below */ @@ -757,10 +455,8 @@ static struct elevator_type iosched_deadline = { .elevator_dispatch_fn = deadline_dispatch_requests, .elevator_add_req_fn = deadline_add_request, .elevator_queue_empty_fn = deadline_queue_empty, - .elevator_former_req_fn = deadline_former_request, - .elevator_latter_req_fn = deadline_latter_request, - .elevator_set_req_fn = deadline_set_request, - .elevator_put_req_fn = deadline_put_request, + .elevator_former_req_fn = elv_rb_former_request, + .elevator_latter_req_fn = elv_rb_latter_request, .elevator_init_fn = deadline_init_queue, .elevator_exit_fn = deadline_exit_queue, }, @@ -772,24 +468,11 @@ static struct elevator_type iosched_deadline = { static int __init deadline_init(void) { - int ret; - - drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq), - 0, 0, NULL, NULL); - - if (!drq_pool) - return -ENOMEM; - - ret = elv_register(&iosched_deadline); - if (ret) - kmem_cache_destroy(drq_pool); - - return ret; + return elv_register(&iosched_deadline); } static void __exit deadline_exit(void) { - kmem_cache_destroy(drq_pool); elv_unregister(&iosched_deadline); }