diff options
Diffstat (limited to 'drivers/block/cfq-iosched.c')
| -rw-r--r-- | drivers/block/cfq-iosched.c | 2428 |
1 files changed, 0 insertions, 2428 deletions
diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c deleted file mode 100644 index ecacca9c877e..000000000000 --- a/drivers/block/cfq-iosched.c +++ /dev/null @@ -1,2428 +0,0 @@ -/* - * linux/drivers/block/cfq-iosched.c - * - * CFQ, or complete fairness queueing, disk scheduler. - * - * Based on ideas from a previously unfinished io - * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. - * - * Copyright (C) 2003 Jens Axboe <axboe@suse.de> - */ -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/bio.h> -#include <linux/config.h> -#include <linux/module.h> -#include <linux/slab.h> -#include <linux/init.h> -#include <linux/compiler.h> -#include <linux/hash.h> -#include <linux/rbtree.h> -#include <linux/mempool.h> -#include <linux/ioprio.h> -#include <linux/writeback.h> - -/* - * tunables - */ -static int cfq_quantum = 4; /* max queue in one round of service */ -static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ -static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; -static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ -static int cfq_back_penalty = 2; /* penalty of a backwards seek */ - -static int cfq_slice_sync = HZ / 10; -static int cfq_slice_async = HZ / 25; -static int cfq_slice_async_rq = 2; -static int cfq_slice_idle = HZ / 100; - -#define CFQ_IDLE_GRACE (HZ / 10) -#define CFQ_SLICE_SCALE (5) - -#define CFQ_KEY_ASYNC (0) -#define CFQ_KEY_ANY (0xffff) - -/* - * disable queueing at the driver/hardware level - */ -static int cfq_max_depth = 2; - -/* - * for the hash of cfqq inside the cfqd - */ -#define CFQ_QHASH_SHIFT 6 -#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) -#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) - -/* - * for the hash of crq inside the cfqq - */ -#define CFQ_MHASH_SHIFT 6 -#define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) -#define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) -#define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) - -#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) -#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) - -#define RQ_DATA(rq) (rq)->elevator_private - -/* - * rb-tree defines - */ -#define RB_NONE (2) -#define RB_EMPTY(node) ((node)->rb_node == NULL) -#define RB_CLEAR_COLOR(node) (node)->rb_color = RB_NONE -#define RB_CLEAR(node) do { \ - (node)->rb_parent = NULL; \ - RB_CLEAR_COLOR((node)); \ - (node)->rb_right = NULL; \ - (node)->rb_left = NULL; \ -} while (0) -#define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) -#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) -#define rq_rb_key(rq) (rq)->sector - -static kmem_cache_t *crq_pool; -static kmem_cache_t *cfq_pool; -static kmem_cache_t *cfq_ioc_pool; - -#define CFQ_PRIO_LISTS IOPRIO_BE_NR -#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) -#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) -#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) - -#define ASYNC (0) -#define SYNC (1) - -#define cfq_cfqq_dispatched(cfqq) \ - ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC]) - -#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC) - -#define cfq_cfqq_sync(cfqq) \ - (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC]) - -/* - * Per block device queue structure - */ -struct cfq_data { - atomic_t ref; - request_queue_t *queue; - - /* - * rr list of queues with requests and the count of them - */ - struct list_head rr_list[CFQ_PRIO_LISTS]; - struct list_head busy_rr; - struct list_head cur_rr; - struct list_head idle_rr; - unsigned int busy_queues; - - /* - * non-ordered list of empty cfqq's - */ - struct list_head empty_list; - - /* - * cfqq lookup hash - */ - struct hlist_head *cfq_hash; - - /* - * global crq hash for all queues - */ - struct hlist_head *crq_hash; - - unsigned int max_queued; - - mempool_t *crq_pool; - - int rq_in_driver; - - /* - * schedule slice state info - */ - /* - * idle window management - */ - struct timer_list idle_slice_timer; - struct work_struct unplug_work; - - struct cfq_queue *active_queue; - struct cfq_io_context *active_cic; - int cur_prio, cur_end_prio; - unsigned int dispatch_slice; - - struct timer_list idle_class_timer; - - sector_t last_sector; - unsigned long last_end_request; - - unsigned int rq_starved; - - /* - * tunables, see top of file - */ - unsigned int cfq_quantum; - unsigned int cfq_queued; - unsigned int cfq_fifo_expire[2]; - unsigned int cfq_back_penalty; - unsigned int cfq_back_max; - unsigned int cfq_slice[2]; - unsigned int cfq_slice_async_rq; - unsigned int cfq_slice_idle; - unsigned int cfq_max_depth; -}; - -/* - * Per process-grouping structure - */ -struct cfq_queue { - /* reference count */ - atomic_t ref; - /* parent cfq_data */ - struct cfq_data *cfqd; - /* cfqq lookup hash */ - struct hlist_node cfq_hash; - /* hash key */ - unsigned int key; - /* on either rr or empty list of cfqd */ - struct list_head cfq_list; - /* sorted list of pending requests */ - struct rb_root sort_list; - /* if fifo isn't expired, next request to serve */ - struct cfq_rq *next_crq; - /* requests queued in sort_list */ - int queued[2]; - /* currently allocated requests */ - int allocated[2]; - /* fifo list of requests in sort_list */ - struct list_head fifo; - - unsigned long slice_start; - unsigned long slice_end; - unsigned long slice_left; - unsigned long service_last; - - /* number of requests that are on the dispatch list */ - int on_dispatch[2]; - - /* io prio of this group */ - unsigned short ioprio, org_ioprio; - unsigned short ioprio_class, org_ioprio_class; - - /* various state flags, see below */ - unsigned int flags; -}; - -struct cfq_rq { - struct rb_node rb_node; - sector_t rb_key; - struct request *request; - struct hlist_node hash; - - struct cfq_queue *cfq_queue; - struct cfq_io_context *io_context; - - unsigned int crq_flags; -}; - -enum cfqq_state_flags { - CFQ_CFQQ_FLAG_on_rr = 0, - CFQ_CFQQ_FLAG_wait_request, - CFQ_CFQQ_FLAG_must_alloc, - CFQ_CFQQ_FLAG_must_alloc_slice, - CFQ_CFQQ_FLAG_must_dispatch, - CFQ_CFQQ_FLAG_fifo_expire, - CFQ_CFQQ_FLAG_idle_window, - CFQ_CFQQ_FLAG_prio_changed, - CFQ_CFQQ_FLAG_expired, -}; - -#define CFQ_CFQQ_FNS(name) \ -static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \ -{ \ - cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \ -} \ -static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \ -{ \ - return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \ -} - -CFQ_CFQQ_FNS(on_rr); -CFQ_CFQQ_FNS(wait_request); -CFQ_CFQQ_FNS(must_alloc); -CFQ_CFQQ_FNS(must_alloc_slice); -CFQ_CFQQ_FNS(must_dispatch); -CFQ_CFQQ_FNS(fifo_expire); -CFQ_CFQQ_FNS(idle_window); -CFQ_CFQQ_FNS(prio_changed); -CFQ_CFQQ_FNS(expired); -#undef CFQ_CFQQ_FNS - -enum cfq_rq_state_flags { - CFQ_CRQ_FLAG_is_sync = 0, -}; - -#define CFQ_CRQ_FNS(name) \ -static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline int cfq_crq_##name(const struct cfq_rq *crq) \ -{ \ - return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ -} - -CFQ_CRQ_FNS(is_sync); -#undef CFQ_CRQ_FNS - -static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); -static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); -static void cfq_put_cfqd(struct cfq_data *cfqd); - -#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) - -/* - * lots of deadline iosched dupes, can be abstracted later... - */ -static inline void cfq_del_crq_hash(struct cfq_rq *crq) -{ - hlist_del_init(&crq->hash); -} - -static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) -{ - const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); - - hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); -} - -static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) -{ - struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; - struct hlist_node *entry, *next; - - hlist_for_each_safe(entry, next, hash_list) { - struct cfq_rq *crq = list_entry_hash(entry); - struct request *__rq = crq->request; - - if (!rq_mergeable(__rq)) { - cfq_del_crq_hash(crq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - -/* - * scheduler run of queue, if there are requests pending and no one in the - * driver that will restart queueing - */ -static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) -{ - if (!cfqd->rq_in_driver && cfqd->busy_queues) - kblockd_schedule_work(&cfqd->unplug_work); -} - -static int cfq_queue_empty(request_queue_t *q) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - return !cfqd->busy_queues; -} - -/* - * Lifted from AS - choose which of crq1 and crq2 that is best served now. - * We choose the request that is closest to the head right now. Distance - * behind the head are penalized and only allowed to a certain extent. - */ -static struct cfq_rq * -cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) -{ - sector_t last, s1, s2, d1 = 0, d2 = 0; - int r1_wrap = 0, r2_wrap = 0; /* requests are behind the disk head */ - unsigned long back_max; - - if (crq1 == NULL || crq1 == crq2) - return crq2; - if (crq2 == NULL) - return crq1; - - if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) - return crq1; - else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) - return crq2; - - s1 = crq1->request->sector; - s2 = crq2->request->sector; - - last = cfqd->last_sector; - - /* - * by definition, 1KiB is 2 sectors - */ - back_max = cfqd->cfq_back_max * 2; - - /* - * Strict one way elevator _except_ in the case where we allow - * short backward seeks which are biased as twice the cost of a - * similar forward seek. - */ - if (s1 >= last) - d1 = s1 - last; - else if (s1 + back_max >= last) - d1 = (last - s1) * cfqd->cfq_back_penalty; - else - r1_wrap = 1; - - if (s2 >= last) - d2 = s2 - last; - else if (s2 + back_max >= last) - d2 = (last - s2) * cfqd->cfq_back_penalty; - else - r2_wrap = 1; - - /* Found required data */ - if (!r1_wrap && r2_wrap) - return crq1; - else if (!r2_wrap && r1_wrap) - return crq2; - else if (r1_wrap && r2_wrap) { - /* both behind the head */ - if (s1 <= s2) - return crq1; - else - return crq2; - } - - /* Both requests in front of the head */ - if (d1 < d2) - return crq1; - else if (d2 < d1) - return crq2; - else { - if (s1 >= s2) - return crq1; - else - return crq2; - } -} - -/* - * would be nice to take fifo expire time into account as well - */ -static struct cfq_rq * -cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *last) -{ - struct cfq_rq *crq_next = NULL, *crq_prev = NULL; - struct rb_node *rbnext, *rbprev; - - if (!(rbnext = rb_next(&last->rb_node))) { - rbnext = rb_first(&cfqq->sort_list); - if (rbnext == &last->rb_node) - rbnext = NULL; - } - - rbprev = rb_prev(&last->rb_node); - - if (rbprev) - crq_prev = rb_entry_crq(rbprev); - if (rbnext) - crq_next = rb_entry_crq(rbnext); - - return cfq_choose_req(cfqd, crq_next, crq_prev); -} - -static void cfq_update_next_crq(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - - if (cfqq->next_crq == crq) - cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); -} - -static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) -{ - struct cfq_data *cfqd = cfqq->cfqd; - struct list_head *list, *entry; - - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - - list_del(&cfqq->cfq_list); - - if (cfq_class_rt(cfqq)) - list = &cfqd->cur_rr; - else if (cfq_class_idle(cfqq)) - list = &cfqd->idle_rr; - else { - /* - * if cfqq has requests in flight, don't allow it to be - * found in cfq_set_active_queue before it has finished them. - * this is done to increase fairness between a process that - * has lots of io pending vs one that only generates one - * sporadically or synchronously - */ - if (cfq_cfqq_dispatched(cfqq)) - list = &cfqd->busy_rr; - else - list = &cfqd->rr_list[cfqq->ioprio]; - } - - /* - * if queue was preempted, just add to front to be fair. busy_rr - * isn't sorted. - */ - if (preempted || list == &cfqd->busy_rr) { - list_add(&cfqq->cfq_list, list); - return; - } - - /* - * sort by when queue was last serviced - */ - entry = list; - while ((entry = entry->prev) != list) { - struct cfq_queue *__cfqq = list_entry_cfqq(entry); - - if (!__cfqq->service_last) - break; - if (time_before(__cfqq->service_last, cfqq->service_last)) - break; - } - - list_add(&cfqq->cfq_list, entry); -} - -/* - * add to busy list of queues for service, trying to be fair in ordering - * the pending list according to last request service - */ -static inline void -cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - BUG_ON(cfq_cfqq_on_rr(cfqq)); - cfq_mark_cfqq_on_rr(cfqq); - cfqd->busy_queues++; - - cfq_resort_rr_list(cfqq, 0); -} - -static inline void -cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - cfq_clear_cfqq_on_rr(cfqq); - list_move(&cfqq->cfq_list, &cfqd->empty_list); - - BUG_ON(!cfqd->busy_queues); - cfqd->busy_queues--; -} - -/* - * rb tree support functions - */ -static inline void cfq_del_crq_rb(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); - - BUG_ON(!cfqq->queued[sync]); - cfqq->queued[sync]--; - - cfq_update_next_crq(crq); - - rb_erase(&crq->rb_node, &cfqq->sort_list); - RB_CLEAR_COLOR(&crq->rb_node); - - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) - cfq_del_cfqq_rr(cfqd, cfqq); -} - -static struct cfq_rq * -__cfq_add_crq_rb(struct cfq_rq *crq) -{ - struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; - struct rb_node *parent = NULL; - struct cfq_rq *__crq; - - while (*p) { - parent = *p; - __crq = rb_entry_crq(parent); - - if (crq->rb_key < __crq->rb_key) - p = &(*p)->rb_left; - else if (crq->rb_key > __crq->rb_key) - p = &(*p)->rb_right; - else - return __crq; - } - - rb_link_node(&crq->rb_node, parent, p); - return NULL; -} - -static void cfq_add_crq_rb(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq = crq->request; - struct cfq_rq *__alias; - - crq->rb_key = rq_rb_key(rq); - cfqq->queued[cfq_crq_is_sync(crq)]++; - - /* - * looks a little odd, but the first insert might return an alias. - * if that happens, put the alias on the dispatch list - */ - while ((__alias = __cfq_add_crq_rb(crq)) != NULL) - cfq_dispatch_insert(cfqd->queue, __alias); - - rb_insert_color(&crq->rb_node, &cfqq->sort_list); - - if (!cfq_cfqq_on_rr(cfqq)) - cfq_add_cfqq_rr(cfqd, cfqq); - - /* - * check if this request is a better next-serve candidate - */ - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); -} - -static inline void -cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) -{ - rb_erase(&crq->rb_node, &cfqq->sort_list); - cfqq->queued[cfq_crq_is_sync(crq)]--; - - cfq_add_crq_rb(crq); -} - -static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) - -{ - struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); - struct rb_node *n; - - if (!cfqq) - goto out; - - n = cfqq->sort_list.rb_node; - while (n) { - struct cfq_rq *crq = rb_entry_crq(n); - - if (sector < crq->rb_key) - n = n->rb_left; - else if (sector > crq->rb_key) - n = n->rb_right; - else - return crq->request; - } - -out: - return NULL; -} - -static void cfq_activate_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - cfqd->rq_in_driver++; -} - -static void cfq_deactivate_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; -} - -static void cfq_remove_request(struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - - list_del_init(&rq->queuelist); - cfq_del_crq_rb(crq); - cfq_del_crq_hash(crq); -} - -static int -cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request *__rq; - int ret; - - __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } - - __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; - } - - return ELEVATOR_NO_MERGE; -out: - *req = __rq; - return ret; -} - -static void cfq_merged_request(request_queue_t *q, struct request *req) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(req); - - cfq_del_crq_hash(crq); - cfq_add_crq_hash(cfqd, crq); - - if (rq_rb_key(req) != crq->rb_key) { - struct cfq_queue *cfqq = crq->cfq_queue; - - cfq_update_next_crq(crq); - cfq_reposition_crq_rb(cfqq, crq); - } -} - -static void -cfq_merged_requests(request_queue_t *q, struct request *rq, - struct request *next) -{ - cfq_merged_request(q, rq); - - /* - * reposition in fifo if next is older than rq - */ - if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && - time_before(next->start_time, rq->start_time)) - list_move(&rq->queuelist, &next->queuelist); - - cfq_remove_request(next); -} - -static inline void -__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - if (cfqq) { - /* - * stop potential idle class queues waiting service - */ - del_timer(&cfqd->idle_class_timer); - - cfqq->slice_start = jiffies; - cfqq->slice_end = 0; - cfqq->slice_left = 0; - cfq_clear_cfqq_must_alloc_slice(cfqq); - cfq_clear_cfqq_fifo_expire(cfqq); - cfq_clear_cfqq_expired(cfqq); - } - - cfqd->active_queue = cfqq; -} - -/* - * 0 - * 0,1 - * 0,1,2 - * 0,1,2,3 - * 0,1,2,3,4 - * 0,1,2,3,4,5 - * 0,1,2,3,4,5,6 - * 0,1,2,3,4,5,6,7 - */ -static int cfq_get_next_prio_level(struct cfq_data *cfqd) -{ - int prio, wrap; - - prio = -1; - wrap = 0; - do { - int p; - - for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) { - if (!list_empty(&cfqd->rr_list[p])) { - prio = p; - break; - } - } - - if (prio != -1) - break; - cfqd->cur_prio = 0; - if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) { - cfqd->cur_end_prio = 0; - if (wrap) - break; - wrap = 1; - } - } while (1); - - if (unlikely(prio == -1)) - return -1; - - BUG_ON(prio >= CFQ_PRIO_LISTS); - - list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr); - - cfqd->cur_prio = prio + 1; - if (cfqd->cur_prio > cfqd->cur_end_prio) { - cfqd->cur_end_prio = cfqd->cur_prio; - cfqd->cur_prio = 0; - } - if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) { - cfqd->cur_prio = 0; - cfqd->cur_end_prio = 0; - } - - return prio; -} - -static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - - /* - * if current queue is expired but not done with its requests yet, - * wait for that to happen - */ - if ((cfqq = cfqd->active_queue) != NULL) { - if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq)) - return NULL; - } - - /* - * if current list is non-empty, grab first entry. if it is empty, - * get next prio level and grab first entry then if any are spliced - */ - if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) - cfqq = list_entry_cfqq(cfqd->cur_rr.next); - - /* - * if we have idle queues and no rt or be queues had pending - * requests, either allow immediate service if the grace period - * has passed or arm the idle grace timer - */ - if (!cfqq && !list_empty(&cfqd->idle_rr)) { - unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE; - - if (time_after_eq(jiffies, end)) - cfqq = list_entry_cfqq(cfqd->idle_rr.next); - else - mod_timer(&cfqd->idle_class_timer, end); - } - - __cfq_set_active_queue(cfqd, cfqq); - return cfqq; -} - -/* - * current cfqq expired its slice (or was too idle), select new one - */ -static void -__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int preempted) -{ - unsigned long now = jiffies; - - if (cfq_cfqq_wait_request(cfqq)) - del_timer(&cfqd->idle_slice_timer); - - if (!preempted && !cfq_cfqq_dispatched(cfqq)) - cfqq->service_last = now; - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - - /* - * store what was left of this slice, if the queue idled out - * or was preempted - */ - if (time_after(now, cfqq->slice_end)) - cfqq->slice_left = now - cfqq->slice_end; - else - cfqq->slice_left = 0; - - if (cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, preempted); - - if (cfqq == cfqd->active_queue) - cfqd->active_queue = NULL; - - if (cfqd->active_cic) { - put_io_context(cfqd->active_cic->ioc); - cfqd->active_cic = NULL; - } - - cfqd->dispatch_slice = 0; -} - -static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfqq) { - /* - * use deferred expiry, if there are requests in progress as - * not to disturb the slice of the next queue - */ - if (cfq_cfqq_dispatched(cfqq)) - cfq_mark_cfqq_expired(cfqq); - else - __cfq_slice_expired(cfqd, cfqq, preempted); - } -} - -static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) - -{ - WARN_ON(!RB_EMPTY(&cfqq->sort_list)); - WARN_ON(cfqq != cfqd->active_queue); - - /* - * idle is disabled, either manually or by past process history - */ - if (!cfqd->cfq_slice_idle) - return 0; - if (!cfq_cfqq_idle_window(cfqq)) - return 0; - /* - * task has exited, don't wait - */ - if (cfqd->active_cic && !cfqd->active_cic->ioc->task) - return 0; - - cfq_mark_cfqq_must_dispatch(cfqq); - cfq_mark_cfqq_wait_request(cfqq); - - if (!timer_pending(&cfqd->idle_slice_timer)) { - unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); - - cfqd->idle_slice_timer.expires = jiffies + slice_left; - add_timer(&cfqd->idle_slice_timer); - } - - return 1; -} - -static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = crq->cfq_queue; - - cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); - cfq_remove_request(crq->request); - cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; - elv_dispatch_sort(q, crq->request); -} - -/* - * return expired entry, or NULL to just start from scratch in rbtree - */ -static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq; - struct cfq_rq *crq; - - if (cfq_cfqq_fifo_expire(cfqq)) - return NULL; - - if (!list_empty(&cfqq->fifo)) { - int fifo = cfq_cfqq_class_sync(cfqq); - - crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); - rq = crq->request; - if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { - cfq_mark_cfqq_fifo_expire(cfqq); - return crq; - } - } - - return NULL; -} - -/* - * Scale schedule slice based on io priority. Use the sync time slice only - * if a queue is marked sync and has sync io queued. A sync queue with async - * io only, should not get full sync slice length. - */ -static inline int -cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)]; - - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); - - return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio)); -} - -static inline void -cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; -} - -static inline int -cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - const int base_rq = cfqd->cfq_slice_async_rq; - - WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); - - return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); -} - -/* - * get next queue for service - */ -static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force) -{ - unsigned long now = jiffies; - struct cfq_queue *cfqq; - - cfqq = cfqd->active_queue; - if (!cfqq) - goto new_queue; - - if (cfq_cfqq_expired(cfqq)) - goto new_queue; - - /* - * slice has expired - */ - if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) - goto expire; - - /* - * if queue has requests, dispatch one. if not, check if - * enough slice is left to wait for one - */ - if (!RB_EMPTY(&cfqq->sort_list)) - goto keep_queue; - else if (!force && cfq_cfqq_class_sync(cfqq) && - time_before(now, cfqq->slice_end)) { - if (cfq_arm_slice_timer(cfqd, cfqq)) - return NULL; - } - -expire: - cfq_slice_expired(cfqd, 0); -new_queue: - cfqq = cfq_set_active_queue(cfqd); -keep_queue: - return cfqq; -} - -static int -__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, - int max_dispatch) -{ - int dispatched = 0; - - BUG_ON(RB_EMPTY(&cfqq->sort_list)); - - do { - struct cfq_rq *crq; - - /* - * follow expired path, else get first next available - */ - if ((crq = cfq_check_fifo(cfqq)) == NULL) - crq = cfqq->next_crq; - - /* - * finally, insert request into driver dispatch list - */ - cfq_dispatch_insert(cfqd->queue, crq); - - cfqd->dispatch_slice++; - dispatched++; - - if (!cfqd->active_cic) { - atomic_inc(&crq->io_context->ioc->refcount); - cfqd->active_cic = crq->io_context; - } - - if (RB_EMPTY(&cfqq->sort_list)) - break; - - } while (dispatched < max_dispatch); - - /* - * if slice end isn't set yet, set it. if at least one request was - * sync, use the sync time slice value - */ - if (!cfqq->slice_end) - cfq_set_prio_slice(cfqd, cfqq); - - /* - * expire an async queue immediately if it has used up its slice. idle - * queue always expire after 1 dispatch round. - */ - if ((!cfq_cfqq_sync(cfqq) && - cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) || - cfq_class_idle(cfqq)) - cfq_slice_expired(cfqd, 0); - - return dispatched; -} - -static int -cfq_dispatch_requests(request_queue_t *q, int force) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq; - - if (!cfqd->busy_queues) - return 0; - - cfqq = cfq_select_queue(cfqd, force); - if (cfqq) { - int max_dispatch; - - /* - * if idle window is disabled, allow queue buildup - */ - if (!cfq_cfqq_idle_window(cfqq) && - cfqd->rq_in_driver >= cfqd->cfq_max_depth) - return 0; - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - del_timer(&cfqd->idle_slice_timer); - - if (!force) { - max_dispatch = cfqd->cfq_quantum; - if (cfq_class_idle(cfqq)) - max_dispatch = 1; - } else - max_dispatch = INT_MAX; - - return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); - } - - return 0; -} - -/* - * task holds one reference to the queue, dropped when task exits. each crq - * in-flight on this queue also holds a reference, dropped when crq is freed. - * - * queue lock must be held here. - */ -static void cfq_put_queue(struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = cfqq->cfqd; - - BUG_ON(atomic_read(&cfqq->ref) <= 0); - - if (!atomic_dec_and_test(&cfqq->ref)) - return; - - BUG_ON(rb_first(&cfqq->sort_list)); - BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); - BUG_ON(cfq_cfqq_on_rr(cfqq)); - - if (unlikely(cfqd->active_queue == cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - cfq_put_cfqd(cfqq->cfqd); - - /* - * it's on the empty list and still hashed - */ - list_del(&cfqq->cfq_list); - hlist_del(&cfqq->cfq_hash); - kmem_cache_free(cfq_pool, cfqq); -} - -static inline struct cfq_queue * -__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, - const int hashval) -{ - struct hlist_head *hash_list = &cfqd->cfq_hash[hashval]; - struct hlist_node *entry, *next; - - hlist_for_each_safe(entry, next, hash_list) { - struct cfq_queue *__cfqq = list_entry_qhash(entry); - const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio); - - if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) - return __cfqq; - } - - return NULL; -} - -static struct cfq_queue * -cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) -{ - return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); -} - -static void cfq_free_io_context(struct cfq_io_context *cic) -{ - struct cfq_io_context *__cic; - struct list_head *entry, *next; - - list_for_each_safe(entry, next, &cic->list) { - __cic = list_entry(entry, struct cfq_io_context, list); - kmem_cache_free(cfq_ioc_pool, __cic); - } - - kmem_cache_free(cfq_ioc_pool, cic); -} - -/* - * Called with interrupts disabled - */ -static void cfq_exit_single_io_context(struct cfq_io_context *cic) -{ - struct cfq_data *cfqd = cic->cfqq->cfqd; - request_queue_t *q = cfqd->queue; - - WARN_ON(!irqs_disabled()); - - spin_lock(q->queue_lock); - - if (unlikely(cic->cfqq == cfqd->active_queue)) { - __cfq_slice_expired(cfqd, cic->cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - cfq_put_queue(cic->cfqq); - cic->cfqq = NULL; - spin_unlock(q->queue_lock); -} - -/* - * Another task may update the task cic list, if it is doing a queue lookup - * on its behalf. cfq_cic_lock excludes such concurrent updates - */ -static void cfq_exit_io_context(struct cfq_io_context *cic) -{ - struct cfq_io_context *__cic; - struct list_head *entry; - unsigned long flags; - - local_irq_save(flags); - - /* - * put the reference this task is holding to the various queues - */ - list_for_each(entry, &cic->list) { - __cic = list_entry(entry, struct cfq_io_context, list); - cfq_exit_single_io_context(__cic); - } - - cfq_exit_single_io_context(cic); - local_irq_restore(flags); -} - -static struct cfq_io_context * -cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) -{ - struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); - - if (cic) { - INIT_LIST_HEAD(&cic->list); - cic->cfqq = NULL; - cic->key = NULL; - cic->last_end_request = jiffies; - cic->ttime_total = 0; - cic->ttime_samples = 0; - cic->ttime_mean = 0; - cic->dtor = cfq_free_io_context; - cic->exit = cfq_exit_io_context; - } - - return cic; -} - -static void cfq_init_prio_data(struct cfq_queue *cfqq) -{ - struct task_struct *tsk = current; - int ioprio_class; - - if (!cfq_cfqq_prio_changed(cfqq)) - return; - - ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); - switch (ioprio_class) { - default: - printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); - case IOPRIO_CLASS_NONE: - /* - * no prio set, place us in the middle of the BE classes - */ - cfqq->ioprio = task_nice_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_BE; - break; - case IOPRIO_CLASS_RT: - cfqq->ioprio = task_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_RT; - break; - case IOPRIO_CLASS_BE: - cfqq->ioprio = task_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_BE; - break; - case IOPRIO_CLASS_IDLE: - cfqq->ioprio_class = IOPRIO_CLASS_IDLE; - cfqq->ioprio = 7; - cfq_clear_cfqq_idle_window(cfqq); - break; - } - - /* - * keep track of original prio settings in case we have to temporarily - * elevate the priority of this queue - */ - cfqq->org_ioprio = cfqq->ioprio; - cfqq->org_ioprio_class = cfqq->ioprio_class; - - if (cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, 0); - - cfq_clear_cfqq_prio_changed(cfqq); -} - -static inline void changed_ioprio(struct cfq_queue *cfqq) -{ - if (cfqq) { - struct cfq_data *cfqd = cfqq->cfqd; - - spin_lock(cfqd->queue->queue_lock); - cfq_mark_cfqq_prio_changed(cfqq); - cfq_init_prio_data(cfqq); - spin_unlock(cfqd->queue->queue_lock); - } -} - -/* - * callback from sys_ioprio_set, irqs are disabled - */ -static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) -{ - struct cfq_io_context *cic = ioc->cic; - - changed_ioprio(cic->cfqq); - - list_for_each_entry(cic, &cic->list, list) - changed_ioprio(cic->cfqq); - - return 0; -} - -static struct cfq_queue * -cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio, - gfp_t gfp_mask) -{ - const int hashval = hash_long(key, CFQ_QHASH_SHIFT); - struct cfq_queue *cfqq, *new_cfqq = NULL; - -retry: - cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); - - if (!cfqq) { - if (new_cfqq) { - cfqq = new_cfqq; - new_cfqq = NULL; - } else if (gfp_mask & __GFP_WAIT) { - spin_unlock_irq(cfqd->queue->queue_lock); - new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); - spin_lock_irq(cfqd->queue->queue_lock); - goto retry; - } else { - cfqq = kmem_cache_alloc(cfq_pool, gfp_mask); - if (!cfqq) - goto out; - } - - memset(cfqq, 0, sizeof(*cfqq)); - - INIT_HLIST_NODE(&cfqq->cfq_hash); - INIT_LIST_HEAD(&cfqq->cfq_list); - RB_CLEAR_ROOT(&cfqq->sort_list); - INIT_LIST_HEAD(&cfqq->fifo); - - cfqq->key = key; - hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); - atomic_set(&cfqq->ref, 0); - cfqq->cfqd = cfqd; - atomic_inc(&cfqd->ref); - cfqq->service_last = 0; - /* - * set ->slice_left to allow preemption for a new process - */ - cfqq->slice_left = 2 * cfqd->cfq_slice_idle; - cfq_mark_cfqq_idle_window(cfqq); - cfq_mark_cfqq_prio_changed(cfqq); - cfq_init_prio_data(cfqq); - } - - if (new_cfqq) - kmem_cache_free(cfq_pool, new_cfqq); - - atomic_inc(&cfqq->ref); -out: - WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); - return cfqq; -} - -/* - * Setup general io context and cfq io context. There can be several cfq - * io contexts per general io context, if this process is doing io to more - * than one device managed by cfq. Note that caller is holding a reference to - * cfqq, so we don't need to worry about it disappearing - */ -static struct cfq_io_context * -cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) -{ - struct io_context *ioc = NULL; - struct cfq_io_context *cic; - - might_sleep_if(gfp_mask & __GFP_WAIT); - - ioc = get_io_context(gfp_mask); - if (!ioc) - return NULL; - - if ((cic = ioc->cic) == NULL) { - cic = cfq_alloc_io_context(cfqd, gfp_mask); - - if (cic == NULL) - goto err; - - /* - * manually increment generic io_context usage count, it - * cannot go away since we are already holding one ref to it - */ - ioc->cic = cic; - ioc->set_ioprio = cfq_ioc_set_ioprio; - cic->ioc = ioc; - cic->key = cfqd; - atomic_inc(&cfqd->ref); - } else { - struct cfq_io_context *__cic; - - /* - * the first cic on the list is actually the head itself - */ - if (cic->key == cfqd) - goto out; - - /* - * cic exists, check if we already are there. linear search - * should be ok here, the list will usually not be more than - * 1 or a few entries long - */ - list_for_each_entry(__cic, &cic->list, list) { - /* - * this process is already holding a reference to - * this queue, so no need to get one more - */ - if (__cic->key == cfqd) { - cic = __cic; - goto out; - } - } - - /* - * nope, process doesn't have a cic assoicated with this - * cfqq yet. get a new one and add to list - */ - __cic = cfq_alloc_io_context(cfqd, gfp_mask); - if (__cic == NULL) - goto err; - - __cic->ioc = ioc; - __cic->key = cfqd; - atomic_inc(&cfqd->ref); - list_add(&__cic->list, &cic->list); - cic = __cic; - } - -out: - return cic; -err: - put_io_context(ioc); - return NULL; -} - -static void -cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) -{ - unsigned long elapsed, ttime; - - /* - * if this context already has stuff queued, thinktime is from - * last queue not last end - */ -#if 0 - if (time_after(cic->last_end_request, cic->last_queue)) - elapsed = jiffies - cic->last_end_request; - else - elapsed = jiffies - cic->last_queue; -#else - elapsed = jiffies - cic->last_end_request; -#endif - - ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); - - cic->ttime_samples = (7*cic->ttime_samples + 256) / 8; - cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8; - cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples; -} - -#define sample_valid(samples) ((samples) > 80) - -/* - * Disable idle window if the process thinks too long or seeks so much that - * it doesn't matter - */ -static void -cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_io_context *cic) -{ - int enable_idle = cfq_cfqq_idle_window(cfqq); - - if (!cic->ioc->task || !cfqd->cfq_slice_idle) - enable_idle = 0; - else if (sample_valid(cic->ttime_samples)) { - if (cic->ttime_mean > cfqd->cfq_slice_idle) - enable_idle = 0; - else - enable_idle = 1; - } - - if (enable_idle) - cfq_mark_cfqq_idle_window(cfqq); - else - cfq_clear_cfqq_idle_window(cfqq); -} - - -/* - * Check if new_cfqq should preempt the currently active queue. Return 0 for - * no or if we aren't sure, a 1 will cause a preempt. - */ -static int -cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, - struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfq_class_idle(new_cfqq)) - return 0; - - if (!cfqq) - return 1; - - if (cfq_class_idle(cfqq)) - return 1; - if (!cfq_cfqq_wait_request(new_cfqq)) - return 0; - /* - * if it doesn't have slice left, forget it - */ - if (new_cfqq->slice_left < cfqd->cfq_slice_idle) - return 0; - if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) - return 1; - - return 0; -} - -/* - * cfqq preempts the active queue. if we allowed preempt with no slice left, - * let it have half of its nominal slice. - */ -static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - struct cfq_queue *__cfqq, *next; - - list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) - cfq_resort_rr_list(__cfqq, 1); - - if (!cfqq->slice_left) - cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; - - cfqq->slice_end = cfqq->slice_left + jiffies; - __cfq_slice_expired(cfqd, cfqq, 1); - __cfq_set_active_queue(cfqd, cfqq); -} - -/* - * should really be a ll_rw_blk.c helper - */ -static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - request_queue_t *q = cfqd->queue; - - if (!blk_queue_plugged(q)) - q->request_fn(q); - else - __generic_unplug_device(q); -} - -/* - * Called when a new fs request (crq) is added (to cfqq). Check if there's - * something we should do about it - */ -static void -cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *crq) -{ - struct cfq_io_context *cic; - - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); - - /* - * we never wait for an async request and we don't allow preemption - * of an async request. so just return early - */ - if (!cfq_crq_is_sync(crq)) - return; - - cic = crq->io_context; - - cfq_update_io_thinktime(cfqd, cic); - cfq_update_idle_window(cfqd, cfqq, cic); - - cic->last_queue = jiffies; - - if (cfqq == cfqd->active_queue) { - /* - * if we are waiting for a request for this queue, let it rip - * immediately and flag that we must not expire this queue - * just now - */ - if (cfq_cfqq_wait_request(cfqq)) { - cfq_mark_cfqq_must_dispatch(cfqq); - del_timer(&cfqd->idle_slice_timer); - cfq_start_queueing(cfqd, cfqq); - } - } else if (cfq_should_preempt(cfqd, cfqq, crq)) { - /* - * not the active queue - expire current slice if it is - * idle and has expired it's mean thinktime or this new queue - * has some old slice time left and is of higher priority - */ - cfq_preempt_queue(cfqd, cfqq); - cfq_mark_cfqq_must_dispatch(cfqq); - cfq_start_queueing(cfqd, cfqq); - } -} - -static void cfq_insert_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; - - cfq_init_prio_data(cfqq); - - cfq_add_crq_rb(crq); - - list_add_tail(&rq->queuelist, &cfqq->fifo); - - if (rq_mergeable(rq)) - cfq_add_crq_hash(cfqd, crq); - - cfq_crq_enqueued(cfqd, cfqq, crq); -} - -static void cfq_completed_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); - unsigned long now; - - now = jiffies; - - WARN_ON(!cfqd->rq_in_driver); - WARN_ON(!cfqq->on_dispatch[sync]); - cfqd->rq_in_driver--; - cfqq->on_dispatch[sync]--; - - if (!cfq_class_idle(cfqq)) - cfqd->last_end_request = now; - - if (!cfq_cfqq_dispatched(cfqq)) { - if (cfq_cfqq_on_rr(cfqq)) { - cfqq->service_last = now; - cfq_resort_rr_list(cfqq, 0); - } - if (cfq_cfqq_expired(cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - } - - if (cfq_crq_is_sync(crq)) - crq->io_context->last_end_request = now; -} - -static struct request * -cfq_former_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&crq->rb_node); - - if (rbprev) - return rb_entry_crq(rbprev)->request; - - return NULL; -} - -static struct request * -cfq_latter_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&crq->rb_node); - - if (rbnext) - return rb_entry_crq(rbnext)->request; - - return NULL; -} - -/* - * we temporarily boost lower priority queues if they are holding fs exclusive - * resources. they are boosted to normal prio (CLASS_BE/4) - */ -static void cfq_prio_boost(struct cfq_queue *cfqq) -{ - const int ioprio_class = cfqq->ioprio_class; - const int ioprio = cfqq->ioprio; - - if (has_fs_excl()) { - /* - * boost idle prio on transactions that would lock out other - * users of the filesystem - */ - if (cfq_class_idle(cfqq)) - cfqq->ioprio_class = IOPRIO_CLASS_BE; - if (cfqq->ioprio > IOPRIO_NORM) - cfqq->ioprio = IOPRIO_NORM; - } else { - /* - * check if we need to unboost the queue - */ - if (cfqq->ioprio_class != cfqq->org_ioprio_class) - cfqq->ioprio_class = cfqq->org_ioprio_class; - if (cfqq->ioprio != cfqq->org_ioprio) - cfqq->ioprio = cfqq->org_ioprio; - } - - /* - * refile between round-robin lists if we moved the priority class - */ - if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && - cfq_cfqq_on_rr(cfqq)) - cfq_resort_rr_list(cfqq, 0); -} - -static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) -{ - if (rw == READ || process_sync(task)) - return task->pid; - - return CFQ_KEY_ASYNC; -} - -static inline int -__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct task_struct *task, int rw) -{ -#if 1 - if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && - !cfq_cfqq_must_alloc_slice(cfqq)) { - cfq_mark_cfqq_must_alloc_slice(cfqq); - return ELV_MQUEUE_MUST; - } - - return ELV_MQUEUE_MAY; -#else - if (!cfqq || task->flags & PF_MEMALLOC) - return ELV_MQUEUE_MAY; - if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { - if (cfq_cfqq_wait_request(cfqq)) - return ELV_MQUEUE_MUST; - - /* - * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we - * can quickly flood the queue with writes from a single task - */ - if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { - cfq_mark_cfqq_must_alloc_slice(cfqq); - return ELV_MQUEUE_MUST; - } - - return ELV_MQUEUE_MAY; - } - if (cfq_class_idle(cfqq)) - return ELV_MQUEUE_NO; - if (cfqq->allocated[rw] >= cfqd->max_queued) { - struct io_context *ioc = get_io_context(GFP_ATOMIC); - int ret = ELV_MQUEUE_NO; - - if (ioc && ioc->nr_batch_requests) - ret = ELV_MQUEUE_MAY; - - put_io_context(ioc); - return ret; - } - - return ELV_MQUEUE_MAY; -#endif -} - -static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_queue *cfqq; - - /* - * don't force setup of a queue from here, as a call to may_queue - * does not necessarily imply that a request actually will be queued. - * so just lookup a possibly existing queue, or return 'may queue' - * if that fails - */ - cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); - if (cfqq) { - cfq_init_prio_data(cfqq); - cfq_prio_boost(cfqq); - - return __cfq_may_queue(cfqd, cfqq, tsk, rw); - } - - return ELV_MQUEUE_MAY; -} - -static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request_list *rl = &q->rq; - - if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) { - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - } - - if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) { - smp_mb(); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } -} - -/* - * queue lock held here - */ -static void cfq_put_request(request_queue_t *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - - if (crq) { - struct cfq_queue *cfqq = crq->cfq_queue; - const int rw = rq_data_dir(rq); - - BUG_ON(!cfqq->allocated[rw]); - cfqq->allocated[rw]--; - - put_io_context(crq->io_context->ioc); - - mempool_free(crq, cfqd->crq_pool); - rq->elevator_private = NULL; - - cfq_check_waiters(q, cfqq); - cfq_put_queue(cfqq); - } -} - -/* - * Allocate cfq data structures associated with this request. - */ -static int -cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_io_context *cic; - const int rw = rq_data_dir(rq); - pid_t key = cfq_queue_pid(tsk, rw); - struct cfq_queue *cfqq; - struct cfq_rq *crq; - unsigned long flags; - - might_sleep_if(gfp_mask & __GFP_WAIT); - - cic = cfq_get_io_context(cfqd, key, gfp_mask); - - spin_lock_irqsave(q->queue_lock, flags); - - if (!cic) - goto queue_fail; - - if (!cic->cfqq) { - cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask); - if (!cfqq) - goto queue_fail; - - cic->cfqq = cfqq; - } else - cfqq = cic->cfqq; - - cfqq->allocated[rw]++; - cfq_clear_cfqq_must_alloc(cfqq); - cfqd->rq_starved = 0; - atomic_inc(&cfqq->ref); - spin_unlock_irqrestore(q->queue_lock, flags); - - crq = mempool_alloc(cfqd->crq_pool, gfp_mask); - if (crq) { - RB_CLEAR(&crq->rb_node); - crq->rb_key = 0; - crq->request = rq; - INIT_HLIST_NODE(&crq->hash); - crq->cfq_queue = cfqq; - crq->io_context = cic; - - if (rw == READ || process_sync(tsk)) - cfq_mark_crq_is_sync(crq); - else - cfq_clear_crq_is_sync(crq); - - rq->elevator_private = crq; - return 0; - } - - spin_lock_irqsave(q->queue_lock, flags); - cfqq->allocated[rw]--; - if (!(cfqq->allocated[0] + cfqq->allocated[1])) - cfq_mark_cfqq_must_alloc(cfqq); - cfq_put_queue(cfqq); -queue_fail: - if (cic) - put_io_context(cic->ioc); - /* - * mark us rq allocation starved. we need to kickstart the process - * ourselves if there are no pending requests that can do it for us. - * that would be an extremely rare OOM situation - */ - cfqd->rq_starved = 1; - cfq_schedule_dispatch(cfqd); - spin_unlock_irqrestore(q->queue_lock, flags); - return 1; -} - -static void cfq_kick_queue(void *data) -{ - request_queue_t *q = data; - struct cfq_data *cfqd = q->elevator->elevator_data; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - - if (cfqd->rq_starved) { - struct request_list *rl = &q->rq; - - /* - * we aren't guaranteed to get a request after this, but we - * have to be opportunistic - */ - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } - - blk_remove_plug(q); - q->request_fn(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} - -/* - * Timer running if the active_queue is currently idling inside its time slice - */ -static void cfq_idle_slice_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - struct cfq_queue *cfqq; - unsigned long flags; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - if ((cfqq = cfqd->active_queue) != NULL) { - unsigned long now = jiffies; - - /* - * expired - */ - if (time_after(now, cfqq->slice_end)) - goto expire; - - /* - * only expire and reinvoke request handler, if there are - * other queues with pending requests - */ - if (!cfqd->busy_queues) { - cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); - add_timer(&cfqd->idle_slice_timer); - goto out_cont; - } - - /* - * not expired and it has a request pending, let it dispatch - */ - if (!RB_EMPTY(&cfqq->sort_list)) { - cfq_mark_cfqq_must_dispatch(cfqq); - goto out_kick; - } - } -expire: - cfq_slice_expired(cfqd, 0); -out_kick: - cfq_schedule_dispatch(cfqd); -out_cont: - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - -/* - * Timer running if an idle class queue is waiting for service - */ -static void cfq_idle_class_timer(unsigned long data) -{ - struct cfq_data *cfqd = (struct cfq_data *) data; - unsigned long flags, end; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - /* - * race with a non-idle queue, reset timer - */ - end = cfqd->last_end_request + CFQ_IDLE_GRACE; - if (!time_after_eq(jiffies, end)) { - cfqd->idle_class_timer.expires = end; - add_timer(&cfqd->idle_class_timer); - } else - cfq_schedule_dispatch(cfqd); - - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); -} - -static void cfq_shutdown_timer_wq(struct cfq_data *cfqd) -{ - del_timer_sync(&cfqd->idle_slice_timer); - del_timer_sync(&cfqd->idle_class_timer); - blk_sync_queue(cfqd->queue); -} - -static void cfq_put_cfqd(struct cfq_data *cfqd) -{ - request_queue_t *q = cfqd->queue; - - if (!atomic_dec_and_test(&cfqd->ref)) - return; - - cfq_shutdown_timer_wq(cfqd); - blk_put_queue(q); - - mempool_destroy(cfqd->crq_pool); - kfree(cfqd->crq_hash); - kfree(cfqd->cfq_hash); - kfree(cfqd); -} - -static void cfq_exit_queue(elevator_t *e) -{ - struct cfq_data *cfqd = e->elevator_data; - - cfq_shutdown_timer_wq(cfqd); - cfq_put_cfqd(cfqd); -} - -static int cfq_init_queue(request_queue_t *q, elevator_t *e) -{ - struct cfq_data *cfqd; - int i; - - cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); - if (!cfqd) - return -ENOMEM; - - memset(cfqd, 0, sizeof(*cfqd)); - - for (i = 0; i < CFQ_PRIO_LISTS; i++) - INIT_LIST_HEAD(&cfqd->rr_list[i]); - - INIT_LIST_HEAD(&cfqd->busy_rr); - INIT_LIST_HEAD(&cfqd->cur_rr); - INIT_LIST_HEAD(&cfqd->idle_rr); - INIT_LIST_HEAD(&cfqd->empty_list); - - cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); - if (!cfqd->crq_hash) - goto out_crqhash; - - cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); - if (!cfqd->cfq_hash) - goto out_cfqhash; - - cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool); - if (!cfqd->crq_pool) - goto out_crqpool; - - for (i = 0; i < CFQ_MHASH_ENTRIES; i++) - INIT_HLIST_HEAD(&cfqd->crq_hash[i]); - for (i = 0; i < CFQ_QHASH_ENTRIES; i++) - INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); - - e->elevator_data = cfqd; - - cfqd->queue = q; - atomic_inc(&q->refcnt); - - cfqd->max_queued = q->nr_requests / 4; - q->nr_batching = cfq_queued; - - init_timer(&cfqd->idle_slice_timer); - cfqd->idle_slice_timer.function = cfq_idle_slice_timer; - cfqd->idle_slice_timer.data = (unsigned long) cfqd; - - init_timer(&cfqd->idle_class_timer); - cfqd->idle_class_timer.function = cfq_idle_class_timer; - cfqd->idle_class_timer.data = (unsigned long) cfqd; - - INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); - - atomic_set(&cfqd->ref, 1); - - cfqd->cfq_queued = cfq_queued; - cfqd->cfq_quantum = cfq_quantum; - cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; - cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; - cfqd->cfq_back_max = cfq_back_max; - cfqd->cfq_back_penalty = cfq_back_penalty; - cfqd->cfq_slice[0] = cfq_slice_async; - cfqd->cfq_slice[1] = cfq_slice_sync; - cfqd->cfq_slice_async_rq = cfq_slice_async_rq; - cfqd->cfq_slice_idle = cfq_slice_idle; - cfqd->cfq_max_depth = cfq_max_depth; - - return 0; -out_crqpool: - kfree(cfqd->cfq_hash); -out_cfqhash: - kfree(cfqd->crq_hash); -out_crqhash: - kfree(cfqd); - return -ENOMEM; -} - -static void cfq_slab_kill(void) -{ - if (crq_pool) - kmem_cache_destroy(crq_pool); - if (cfq_pool) - kmem_cache_destroy(cfq_pool); - if (cfq_ioc_pool) - kmem_cache_destroy(cfq_ioc_pool); -} - -static int __init cfq_slab_setup(void) -{ - crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, - NULL, NULL); - if (!crq_pool) - goto fail; - - cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, - NULL, NULL); - if (!cfq_pool) - goto fail; - - cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool", - sizeof(struct cfq_io_context), 0, 0, NULL, NULL); - if (!cfq_ioc_pool) - goto fail; - - return 0; -fail: - cfq_slab_kill(); - return -ENOMEM; -} - -/* - * sysfs parts below --> - */ -struct cfq_fs_entry { - struct attribute attr; - ssize_t (*show)(struct cfq_data *, char *); - ssize_t (*store)(struct cfq_data *, const char *, size_t); -}; - -static ssize_t -cfq_var_show(unsigned int var, char *page) -{ - return sprintf(page, "%d\n", var); -} - -static ssize_t -cfq_var_store(unsigned int *var, const char *page, size_t count) -{ - char *p = (char *) page; - - *var = simple_strtoul(p, &p, 10); - return count; -} - -#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \ -static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \ -{ \ - unsigned int __data = __VAR; \ - if (__CONV) \ - __data = jiffies_to_msecs(__data); \ - return cfq_var_show(__data, (page)); \ -} -SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); -SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); -SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); -SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); -SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); -SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); -SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1); -SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1); -SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1); -SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0); -SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0); -#undef SHOW_FUNCTION - -#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ -static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count) \ -{ \ - unsigned int __data; \ - int ret = cfq_var_store(&__data, (page), count); \ - if (__data < (MIN)) \ - __data = (MIN); \ - else if (__data > (MAX)) \ - __data = (MAX); \ - if (__CONV) \ - *(__PTR) = msecs_to_jiffies(__data); \ - else \ - *(__PTR) = __data; \ - return ret; \ -} -STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); -STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1); -STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0); -#undef STORE_FUNCTION - -static struct cfq_fs_entry cfq_quantum_entry = { - .attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_quantum_show, - .store = cfq_quantum_store, -}; -static struct cfq_fs_entry cfq_queued_entry = { - .attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_queued_show, - .store = cfq_queued_store, -}; -static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { - .attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_fifo_expire_sync_show, - .store = cfq_fifo_expire_sync_store, -}; -static struct cfq_fs_entry cfq_fifo_expire_async_entry = { - .attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_fifo_expire_async_show, - .store = cfq_fifo_expire_async_store, -}; -static struct cfq_fs_entry cfq_back_max_entry = { - .attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_back_max_show, - .store = cfq_back_max_store, -}; -static struct cfq_fs_entry cfq_back_penalty_entry = { - .attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_back_penalty_show, - .store = cfq_back_penalty_store, -}; -static struct cfq_fs_entry cfq_slice_sync_entry = { - .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_sync_show, - .store = cfq_slice_sync_store, -}; -static struct cfq_fs_entry cfq_slice_async_entry = { - .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_async_show, - .store = cfq_slice_async_store, -}; -static struct cfq_fs_entry cfq_slice_async_rq_entry = { - .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_async_rq_show, - .store = cfq_slice_async_rq_store, -}; -static struct cfq_fs_entry cfq_slice_idle_entry = { - .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_slice_idle_show, - .store = cfq_slice_idle_store, -}; -static struct cfq_fs_entry cfq_max_depth_entry = { - .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR }, - .show = cfq_max_depth_show, - .store = cfq_max_depth_store, -}; - -static struct attribute *default_attrs[] = { - &cfq_quantum_entry.attr, - &cfq_queued_entry.attr, - &cfq_fifo_expire_sync_entry.attr, - &cfq_fifo_expire_async_entry.attr, - &cfq_back_max_entry.attr, - &cfq_back_penalty_entry.attr, - &cfq_slice_sync_entry.attr, - &cfq_slice_async_entry.attr, - &cfq_slice_async_rq_entry.attr, - &cfq_slice_idle_entry.attr, - &cfq_max_depth_entry.attr, - NULL, -}; - -#define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr) - -static ssize_t -cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct cfq_fs_entry *entry = to_cfq(attr); - - if (!entry->show) - return -EIO; - - return entry->show(e->elevator_data, page); -} - -static ssize_t -cfq_attr_store(struct kobject *kobj, struct attribute *attr, - const char *page, size_t length) -{ - elevator_t *e = container_of(kobj, elevator_t, kobj); - struct cfq_fs_entry *entry = to_cfq(attr); - - if (!entry->store) - return -EIO; - - return entry->store(e->elevator_data, page, length); -} - -static struct sysfs_ops cfq_sysfs_ops = { - .show = cfq_attr_show, - .store = cfq_attr_store, -}; - -static struct kobj_type cfq_ktype = { - .sysfs_ops = &cfq_sysfs_ops, - .default_attrs = default_attrs, -}; - -static struct elevator_type iosched_cfq = { - .ops = { - .elevator_merge_fn = cfq_merge, - .elevator_merged_fn = cfq_merged_request, - .elevator_merge_req_fn = cfq_merged_requests, - .elevator_dispatch_fn = cfq_dispatch_requests, - .elevator_add_req_fn = cfq_insert_request, - .elevator_activate_req_fn = cfq_activate_request, - .elevator_deactivate_req_fn = cfq_deactivate_request, - .elevator_queue_empty_fn = cfq_queue_empty, - .elevator_completed_req_fn = cfq_completed_request, - .elevator_former_req_fn = cfq_former_request, - .elevator_latter_req_fn = cfq_latter_request, - .elevator_set_req_fn = cfq_set_request, - .elevator_put_req_fn = cfq_put_request, - .elevator_may_queue_fn = cfq_may_queue, - .elevator_init_fn = cfq_init_queue, - .elevator_exit_fn = cfq_exit_queue, - }, - .elevator_ktype = &cfq_ktype, - .elevator_name = "cfq", - .elevator_owner = THIS_MODULE, -}; - -static int __init cfq_init(void) -{ - int ret; - - /* - * could be 0 on HZ < 1000 setups - */ - if (!cfq_slice_async) - cfq_slice_async = 1; - if (!cfq_slice_idle) - cfq_slice_idle = 1; - - if (cfq_slab_setup()) - return -ENOMEM; - - ret = elv_register(&iosched_cfq); - if (ret) - cfq_slab_kill(); - - return ret; -} - -static void __exit cfq_exit(void) -{ - elv_unregister(&iosched_cfq); - cfq_slab_kill(); -} - -module_init(cfq_init); -module_exit(cfq_exit); - -MODULE_AUTHOR("Jens Axboe"); -MODULE_LICENSE("GPL"); -MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |