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block/cfq-iosched.c
58.2 KB
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/* |
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* 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> |
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#include <linux/ioprio.h> #include <linux/writeback.h> |
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/* * tunables */ |
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static const int cfq_quantum = 4; /* max queue in one round of service */ static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ |
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static const int cfq_slice_sync = HZ / 10; |
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static int cfq_slice_async = HZ / 25; |
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static const int cfq_slice_async_rq = 2; |
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static int cfq_slice_idle = HZ / 100; |
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#define CFQ_IDLE_GRACE (HZ / 10) #define CFQ_SLICE_SCALE (5) #define CFQ_KEY_ASYNC (0) |
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#define CFQ_KEY_ANY (0xffff) |
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/* * disable queueing at the driver/hardware level */ |
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static const int cfq_max_depth = 2; |
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/* * 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) |
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#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) |
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#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) |
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#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) #define rq_rb_key(rq) (rq)->sector |
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static kmem_cache_t *crq_pool; static kmem_cache_t *cfq_pool; static kmem_cache_t *cfq_ioc_pool; |
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#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) |
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#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]) |
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/* * Per block device queue structure */ |
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struct cfq_data { |
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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 */ |
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struct list_head empty_list; |
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/* * cfqq lookup hash */ |
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struct hlist_head *cfq_hash; |
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/* * global crq hash for all queues */ struct hlist_head *crq_hash; |
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unsigned int max_queued; |
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mempool_t *crq_pool; |
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int rq_in_driver; |
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/* * schedule slice state info */ /* * idle window management */ struct timer_list idle_slice_timer; struct work_struct unplug_work; |
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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; |
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sector_t last_sector; |
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unsigned long last_end_request; |
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unsigned int rq_starved; |
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/* * tunables, see top of file */ unsigned int cfq_quantum; unsigned int cfq_queued; |
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unsigned int cfq_fifo_expire[2]; |
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unsigned int cfq_back_penalty; unsigned int cfq_back_max; |
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unsigned int cfq_slice[2]; unsigned int cfq_slice_async_rq; unsigned int cfq_slice_idle; unsigned int cfq_max_depth; |
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}; |
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/* * Per process-grouping structure */ |
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struct cfq_queue { /* reference count */ atomic_t ref; /* parent cfq_data */ struct cfq_data *cfqd; |
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/* cfqq lookup hash */ |
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struct hlist_node cfq_hash; /* hash key */ |
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unsigned int key; |
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/* 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 */ |
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struct list_head fifo; |
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unsigned long slice_start; unsigned long slice_end; unsigned long slice_left; unsigned long service_last; |
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/* number of requests that are on the dispatch list */ int on_dispatch[2]; |
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/* io prio of this group */ unsigned short ioprio, org_ioprio; unsigned short ioprio_class, org_ioprio_class; |
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/* various state flags, see below */ unsigned int flags; |
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}; 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; |
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unsigned int crq_flags; |
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}; |
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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 { |
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CFQ_CRQ_FLAG_is_sync = 0, |
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}; #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; \ } |
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CFQ_CRQ_FNS(is_sync); |
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#undef CFQ_CRQ_FNS static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); |
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static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); |
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static void cfq_put_cfqd(struct cfq_data *cfqd); |
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#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) |
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/* * 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); } |
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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)); |
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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; |
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if (!rq_mergeable(__rq)) { cfq_del_crq_hash(crq); continue; } if (rq_hash_key(__rq) == offset) return __rq; } return NULL; } |
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/* * 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) { |
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if (!cfqd->rq_in_driver && cfqd->busy_queues) |
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kblockd_schedule_work(&cfqd->unplug_work); } static int cfq_queue_empty(request_queue_t *q) { struct cfq_data *cfqd = q->elevator->elevator_data; |
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return !cfqd->busy_queues; |
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} |
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/* * 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; |
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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)) |
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return crq2; |
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s1 = crq1->request->sector; s2 = crq2->request->sector; last = cfqd->last_sector; |
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/* * 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; |
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if (!(rbnext = rb_next(&last->rb_node))) { |
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rbnext = rb_first(&cfqq->sort_list); |
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if (rbnext == &last->rb_node) rbnext = NULL; } |
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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); } |
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static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
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{ |
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struct cfq_data *cfqd = cfqq->cfqd; struct list_head *list, *entry; |
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BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
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list_del(&cfqq->cfq_list); |
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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 */ |
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if (cfq_cfqq_dispatched(cfqq)) |
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list = &cfqd->busy_rr; else list = &cfqd->rr_list[cfqq->ioprio]; |
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} |
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/* * 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); |
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return; |
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} |
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/* |
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* sort by when queue was last serviced |
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*/ |
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entry = list; while ((entry = entry->prev) != list) { |
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struct cfq_queue *__cfqq = list_entry_cfqq(entry); |
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if (!__cfqq->service_last) break; if (time_before(__cfqq->service_last, cfqq->service_last)) |
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break; |
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} list_add(&cfqq->cfq_list, entry); } /* * add to busy list of queues for service, trying to be fair in ordering |
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* the pending list according to last request service |
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*/ static inline void |
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cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
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{ |
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BUG_ON(cfq_cfqq_on_rr(cfqq)); cfq_mark_cfqq_on_rr(cfqq); |
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cfqd->busy_queues++; |
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cfq_resort_rr_list(cfqq, 0); |
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} static inline void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) { |
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BUG_ON(!cfq_cfqq_on_rr(cfqq)); cfq_clear_cfqq_on_rr(cfqq); |
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list_move(&cfqq->cfq_list, &cfqd->empty_list); |
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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; |
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struct cfq_data *cfqd = cfqq->cfqd; const int sync = cfq_crq_is_sync(crq); |
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BUG_ON(!cfqq->queued[sync]); cfqq->queued[sync]--; |
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cfq_update_next_crq(crq); |
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rb_erase(&crq->rb_node, &cfqq->sort_list); RB_CLEAR_COLOR(&crq->rb_node); |
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if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) cfq_del_cfqq_rr(cfqd, cfqq); |
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} 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); |
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cfqq->queued[cfq_crq_is_sync(crq)]++; |
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/* * 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) |
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cfq_dispatch_insert(cfqd->queue, __alias); |
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rb_insert_color(&crq->rb_node, &cfqq->sort_list); |
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if (!cfq_cfqq_on_rr(cfqq)) |
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cfq_add_cfqq_rr(cfqd, cfqq); |
1da177e4c
|
579 580 581 582 583 584 585 586 587 588 |
/* * 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) { |
b4878f245
|
589 590 |
rb_erase(&crq->rb_node, &cfqq->sort_list); cfqq->queued[cfq_crq_is_sync(crq)]--; |
1da177e4c
|
591 592 593 |
cfq_add_crq_rb(crq); } |
22e2c507c
|
594 |
static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector) |
1da177e4c
|
595 |
{ |
3b18152c3
|
596 |
struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY); |
1da177e4c
|
597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 |
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; } |
b4878f245
|
617 |
static void cfq_activate_request(request_queue_t *q, struct request *rq) |
1da177e4c
|
618 |
{ |
22e2c507c
|
619 |
struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c3
|
620 |
|
b4878f245
|
621 |
cfqd->rq_in_driver++; |
1da177e4c
|
622 |
} |
b4878f245
|
623 |
static void cfq_deactivate_request(request_queue_t *q, struct request *rq) |
1da177e4c
|
624 |
{ |
b4878f245
|
625 626 627 628 |
struct cfq_data *cfqd = q->elevator->elevator_data; WARN_ON(!cfqd->rq_in_driver); cfqd->rq_in_driver--; |
1da177e4c
|
629 |
} |
b4878f245
|
630 |
static void cfq_remove_request(struct request *rq) |
1da177e4c
|
631 632 |
{ struct cfq_rq *crq = RQ_DATA(rq); |
b4878f245
|
633 634 |
list_del_init(&rq->queuelist); cfq_del_crq_rb(crq); |
98b11471d
|
635 |
cfq_del_crq_hash(crq); |
1da177e4c
|
636 637 638 639 640 641 642 643 |
} 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; |
1da177e4c
|
644 |
__rq = cfq_find_rq_hash(cfqd, bio->bi_sector); |
22e2c507c
|
645 646 647 |
if (__rq && elv_rq_merge_ok(__rq, bio)) { ret = ELEVATOR_BACK_MERGE; goto out; |
1da177e4c
|
648 649 650 |
} __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio)); |
22e2c507c
|
651 652 653 |
if (__rq && elv_rq_merge_ok(__rq, bio)) { ret = ELEVATOR_FRONT_MERGE; goto out; |
1da177e4c
|
654 655 656 657 |
} return ELEVATOR_NO_MERGE; out: |
1da177e4c
|
658 659 660 661 662 663 664 665 666 667 668 |
*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); |
b4878f245
|
669 |
if (rq_rb_key(req) != crq->rb_key) { |
1da177e4c
|
670 671 672 673 674 |
struct cfq_queue *cfqq = crq->cfq_queue; cfq_update_next_crq(crq); cfq_reposition_crq_rb(cfqq, crq); } |
1da177e4c
|
675 676 677 678 679 680 |
} static void cfq_merged_requests(request_queue_t *q, struct request *rq, struct request *next) { |
1da177e4c
|
681 |
cfq_merged_request(q, rq); |
22e2c507c
|
682 683 684 685 686 687 |
/* * 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); |
b4878f245
|
688 |
cfq_remove_request(next); |
22e2c507c
|
689 690 691 692 693 694 695 696 697 698 699 700 701 702 |
} 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; |
3b18152c3
|
703 704 705 |
cfq_clear_cfqq_must_alloc_slice(cfqq); cfq_clear_cfqq_fifo_expire(cfqq); cfq_clear_cfqq_expired(cfqq); |
22e2c507c
|
706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 |
} 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; |
1da177e4c
|
745 |
} |
22e2c507c
|
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 |
} 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; |
1da177e4c
|
763 |
} |
22e2c507c
|
764 765 |
return prio; } |
3b18152c3
|
766 |
static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) |
22e2c507c
|
767 |
{ |
3b18152c3
|
768 769 770 771 772 773 774 775 776 777 |
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; } |
22e2c507c
|
778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 |
/* * 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); |
3b18152c3
|
801 |
return cfqq; |
22e2c507c
|
802 803 804 805 806 |
} /* * current cfqq expired its slice (or was too idle), select new one */ |
3b18152c3
|
807 808 809 |
static void __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, int preempted) |
22e2c507c
|
810 |
{ |
3b18152c3
|
811 |
unsigned long now = jiffies; |
22e2c507c
|
812 |
|
3b18152c3
|
813 814 |
if (cfq_cfqq_wait_request(cfqq)) del_timer(&cfqd->idle_slice_timer); |
22e2c507c
|
815 |
|
3b18152c3
|
816 817 |
if (!preempted && !cfq_cfqq_dispatched(cfqq)) cfqq->service_last = now; |
22e2c507c
|
818 |
|
3b18152c3
|
819 820 |
cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_wait_request(cfqq); |
22e2c507c
|
821 |
|
3b18152c3
|
822 823 824 825 |
/* * store what was left of this slice, if the queue idled out * or was preempted */ |
b740d98f5
|
826 827 |
if (time_after(cfqq->slice_end, now)) cfqq->slice_left = cfqq->slice_end - now; |
3b18152c3
|
828 829 |
else cfqq->slice_left = 0; |
22e2c507c
|
830 |
|
3b18152c3
|
831 832 |
if (cfq_cfqq_on_rr(cfqq)) cfq_resort_rr_list(cfqq, preempted); |
22e2c507c
|
833 |
|
3b18152c3
|
834 |
if (cfqq == cfqd->active_queue) |
22e2c507c
|
835 |
cfqd->active_queue = NULL; |
3b18152c3
|
836 837 838 |
if (cfqd->active_cic) { put_io_context(cfqd->active_cic->ioc); cfqd->active_cic = NULL; |
22e2c507c
|
839 840 841 842 |
} cfqd->dispatch_slice = 0; } |
3b18152c3
|
843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 |
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); } } |
22e2c507c
|
858 859 860 861 862 863 864 865 866 867 868 |
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; |
3b18152c3
|
869 |
if (!cfq_cfqq_idle_window(cfqq)) |
22e2c507c
|
870 871 872 873 874 875 |
return 0; /* * task has exited, don't wait */ if (cfqd->active_cic && !cfqd->active_cic->ioc->task) return 0; |
3b18152c3
|
876 877 |
cfq_mark_cfqq_must_dispatch(cfqq); cfq_mark_cfqq_wait_request(cfqq); |
22e2c507c
|
878 879 |
if (!timer_pending(&cfqd->idle_slice_timer)) { |
3b18152c3
|
880 |
unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
22e2c507c
|
881 |
|
3b18152c3
|
882 |
cfqd->idle_slice_timer.expires = jiffies + slice_left; |
22e2c507c
|
883 884 885 886 |
add_timer(&cfqd->idle_slice_timer); } return 1; |
1da177e4c
|
887 |
} |
b4878f245
|
888 |
static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) |
1da177e4c
|
889 890 891 |
{ struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq = crq->cfq_queue; |
22e2c507c
|
892 893 |
cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); |
b4878f245
|
894 |
cfq_remove_request(crq->request); |
3b18152c3
|
895 |
cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; |
b4878f245
|
896 |
elv_dispatch_sort(q, crq->request); |
1da177e4c
|
897 898 899 900 901 902 903 904 |
} /* * 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; |
22e2c507c
|
905 |
struct request *rq; |
1da177e4c
|
906 |
struct cfq_rq *crq; |
3b18152c3
|
907 |
if (cfq_cfqq_fifo_expire(cfqq)) |
1da177e4c
|
908 |
return NULL; |
22e2c507c
|
909 |
if (!list_empty(&cfqq->fifo)) { |
3b18152c3
|
910 |
int fifo = cfq_cfqq_class_sync(cfqq); |
1da177e4c
|
911 |
|
22e2c507c
|
912 913 914 |
crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); rq = crq->request; if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { |
3b18152c3
|
915 |
cfq_mark_cfqq_fifo_expire(cfqq); |
22e2c507c
|
916 917 |
return crq; } |
1da177e4c
|
918 919 920 921 922 923 |
} return NULL; } /* |
3b18152c3
|
924 925 926 |
* 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. |
1da177e4c
|
927 |
*/ |
22e2c507c
|
928 929 930 931 932 933 934 935 936 |
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)); } |
1da177e4c
|
937 |
static inline void |
22e2c507c
|
938 |
cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
1da177e4c
|
939 |
{ |
22e2c507c
|
940 941 |
cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies; } |
1da177e4c
|
942 |
|
22e2c507c
|
943 944 945 946 |
static inline int cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq) { const int base_rq = cfqd->cfq_slice_async_rq; |
1da177e4c
|
947 |
|
22e2c507c
|
948 |
WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR); |
1da177e4c
|
949 |
|
22e2c507c
|
950 |
return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio)); |
1da177e4c
|
951 |
} |
22e2c507c
|
952 953 954 |
/* * get next queue for service */ |
1b5ed5e1f
|
955 |
static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) |
1da177e4c
|
956 |
{ |
22e2c507c
|
957 |
unsigned long now = jiffies; |
1da177e4c
|
958 |
struct cfq_queue *cfqq; |
1da177e4c
|
959 |
|
22e2c507c
|
960 961 962 |
cfqq = cfqd->active_queue; if (!cfqq) goto new_queue; |
1da177e4c
|
963 |
|
3b18152c3
|
964 965 |
if (cfq_cfqq_expired(cfqq)) goto new_queue; |
22e2c507c
|
966 967 968 |
/* * slice has expired */ |
3b18152c3
|
969 970 |
if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end)) goto expire; |
1da177e4c
|
971 |
|
22e2c507c
|
972 973 974 975 976 977 |
/* * 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; |
1b5ed5e1f
|
978 |
else if (cfq_cfqq_class_sync(cfqq) && |
22e2c507c
|
979 980 981 982 |
time_before(now, cfqq->slice_end)) { if (cfq_arm_slice_timer(cfqd, cfqq)) return NULL; } |
3b18152c3
|
983 |
expire: |
22e2c507c
|
984 |
cfq_slice_expired(cfqd, 0); |
3b18152c3
|
985 986 |
new_queue: cfqq = cfq_set_active_queue(cfqd); |
22e2c507c
|
987 |
keep_queue: |
3b18152c3
|
988 |
return cfqq; |
22e2c507c
|
989 990 991 992 993 994 995 996 997 998 999 1000 |
} 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; |
1da177e4c
|
1001 1002 |
/* |
22e2c507c
|
1003 |
* follow expired path, else get first next available |
1da177e4c
|
1004 |
*/ |
22e2c507c
|
1005 1006 1007 1008 1009 1010 |
if ((crq = cfq_check_fifo(cfqq)) == NULL) crq = cfqq->next_crq; /* * finally, insert request into driver dispatch list */ |
b4878f245
|
1011 |
cfq_dispatch_insert(cfqd->queue, crq); |
1da177e4c
|
1012 |
|
22e2c507c
|
1013 1014 |
cfqd->dispatch_slice++; dispatched++; |
1da177e4c
|
1015 |
|
22e2c507c
|
1016 1017 1018 1019 |
if (!cfqd->active_cic) { atomic_inc(&crq->io_context->ioc->refcount); cfqd->active_cic = crq->io_context; } |
1da177e4c
|
1020 |
|
22e2c507c
|
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 |
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 |
1b5ed5e1f
|
1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 |
cfq_forced_dispatch_cfqqs(struct list_head *list) { int dispatched = 0; struct cfq_queue *cfqq, *next; struct cfq_rq *crq; list_for_each_entry_safe(cfqq, next, list, cfq_list) { while ((crq = cfqq->next_crq)) { cfq_dispatch_insert(cfqq->cfqd->queue, crq); dispatched++; } BUG_ON(!list_empty(&cfqq->fifo)); } return dispatched; } static int cfq_forced_dispatch(struct cfq_data *cfqd) { int i, dispatched = 0; for (i = 0; i < CFQ_PRIO_LISTS; i++) dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]); dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr); dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr); cfq_slice_expired(cfqd, 0); BUG_ON(cfqd->busy_queues); return dispatched; } static int |
b4878f245
|
1082 |
cfq_dispatch_requests(request_queue_t *q, int force) |
22e2c507c
|
1083 1084 1085 1086 1087 1088 |
{ struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq; if (!cfqd->busy_queues) return 0; |
1b5ed5e1f
|
1089 1090 1091 1092 |
if (unlikely(force)) return cfq_forced_dispatch(cfqd); cfqq = cfq_select_queue(cfqd); |
22e2c507c
|
1093 |
if (cfqq) { |
b4878f245
|
1094 1095 1096 1097 1098 1099 1100 1101 |
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; |
3b18152c3
|
1102 1103 |
cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_wait_request(cfqq); |
22e2c507c
|
1104 |
del_timer(&cfqd->idle_slice_timer); |
1b5ed5e1f
|
1105 1106 1107 |
max_dispatch = cfqd->cfq_quantum; if (cfq_class_idle(cfqq)) max_dispatch = 1; |
1da177e4c
|
1108 |
|
22e2c507c
|
1109 |
return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
1da177e4c
|
1110 |
} |
22e2c507c
|
1111 |
return 0; |
1da177e4c
|
1112 |
} |
1da177e4c
|
1113 1114 1115 1116 1117 1118 1119 1120 |
/* * 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) { |
22e2c507c
|
1121 1122 1123 |
struct cfq_data *cfqd = cfqq->cfqd; BUG_ON(atomic_read(&cfqq->ref) <= 0); |
1da177e4c
|
1124 1125 1126 1127 1128 |
if (!atomic_dec_and_test(&cfqq->ref)) return; BUG_ON(rb_first(&cfqq->sort_list)); |
22e2c507c
|
1129 |
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); |
3b18152c3
|
1130 |
BUG_ON(cfq_cfqq_on_rr(cfqq)); |
1da177e4c
|
1131 |
|
22e2c507c
|
1132 |
if (unlikely(cfqd->active_queue == cfqq)) { |
3b18152c3
|
1133 1134 |
__cfq_slice_expired(cfqd, cfqq, 0); cfq_schedule_dispatch(cfqd); |
22e2c507c
|
1135 |
} |
1da177e4c
|
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 |
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 * |
3b18152c3
|
1147 1148 |
__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, const int hashval) |
1da177e4c
|
1149 1150 1151 1152 1153 1154 |
{ 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); |
3b18152c3
|
1155 |
const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio); |
1da177e4c
|
1156 |
|
3b18152c3
|
1157 |
if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY)) |
1da177e4c
|
1158 1159 1160 1161 1162 1163 1164 |
return __cfqq; } return NULL; } static struct cfq_queue * |
3b18152c3
|
1165 |
cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio) |
1da177e4c
|
1166 |
{ |
3b18152c3
|
1167 |
return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT)); |
1da177e4c
|
1168 |
} |
22e2c507c
|
1169 |
static void cfq_free_io_context(struct cfq_io_context *cic) |
1da177e4c
|
1170 |
{ |
22e2c507c
|
1171 1172 |
struct cfq_io_context *__cic; struct list_head *entry, *next; |
1da177e4c
|
1173 |
|
22e2c507c
|
1174 1175 1176 |
list_for_each_safe(entry, next, &cic->list) { __cic = list_entry(entry, struct cfq_io_context, list); kmem_cache_free(cfq_ioc_pool, __cic); |
1da177e4c
|
1177 |
} |
22e2c507c
|
1178 |
kmem_cache_free(cfq_ioc_pool, cic); |
1da177e4c
|
1179 |
} |
22e2c507c
|
1180 1181 1182 1183 |
/* * Called with interrupts disabled */ static void cfq_exit_single_io_context(struct cfq_io_context *cic) |
1da177e4c
|
1184 |
{ |
22e2c507c
|
1185 1186 1187 1188 1189 1190 1191 1192 |
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)) { |
3b18152c3
|
1193 1194 |
__cfq_slice_expired(cfqd, cic->cfqq, 0); cfq_schedule_dispatch(cfqd); |
22e2c507c
|
1195 1196 1197 1198 1199 |
} cfq_put_queue(cic->cfqq); cic->cfqq = NULL; spin_unlock(q->queue_lock); |
1da177e4c
|
1200 1201 1202 |
} /* |
22e2c507c
|
1203 1204 |
* 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 |
1da177e4c
|
1205 1206 1207 |
*/ static void cfq_exit_io_context(struct cfq_io_context *cic) { |
22e2c507c
|
1208 1209 |
struct cfq_io_context *__cic; struct list_head *entry; |
1da177e4c
|
1210 |
unsigned long flags; |
22e2c507c
|
1211 |
local_irq_save(flags); |
1da177e4c
|
1212 1213 1214 |
/* * put the reference this task is holding to the various queues */ |
22e2c507c
|
1215 |
list_for_each(entry, &cic->list) { |
1da177e4c
|
1216 |
__cic = list_entry(entry, struct cfq_io_context, list); |
22e2c507c
|
1217 |
cfq_exit_single_io_context(__cic); |
1da177e4c
|
1218 |
} |
22e2c507c
|
1219 1220 |
cfq_exit_single_io_context(cic); local_irq_restore(flags); |
1da177e4c
|
1221 |
} |
22e2c507c
|
1222 |
static struct cfq_io_context * |
8267e268e
|
1223 |
cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
1da177e4c
|
1224 |
{ |
22e2c507c
|
1225 |
struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); |
1da177e4c
|
1226 1227 |
if (cic) { |
1da177e4c
|
1228 1229 |
INIT_LIST_HEAD(&cic->list); cic->cfqq = NULL; |
22e2c507c
|
1230 1231 1232 1233 1234 1235 1236 |
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; |
1da177e4c
|
1237 1238 1239 1240 |
} return cic; } |
22e2c507c
|
1241 1242 1243 1244 |
static void cfq_init_prio_data(struct cfq_queue *cfqq) { struct task_struct *tsk = current; int ioprio_class; |
3b18152c3
|
1245 |
if (!cfq_cfqq_prio_changed(cfqq)) |
22e2c507c
|
1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 |
return; ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio); switch (ioprio_class) { default: printk(KERN_ERR "cfq: bad prio %x ", 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; |
3b18152c3
|
1271 |
cfq_clear_cfqq_idle_window(cfqq); |
22e2c507c
|
1272 1273 1274 1275 1276 1277 1278 1279 1280 |
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; |
3b18152c3
|
1281 |
if (cfq_cfqq_on_rr(cfqq)) |
22e2c507c
|
1282 |
cfq_resort_rr_list(cfqq, 0); |
3b18152c3
|
1283 |
cfq_clear_cfqq_prio_changed(cfqq); |
22e2c507c
|
1284 1285 1286 1287 1288 1289 1290 1291 |
} static inline void changed_ioprio(struct cfq_queue *cfqq) { if (cfqq) { struct cfq_data *cfqd = cfqq->cfqd; spin_lock(cfqd->queue->queue_lock); |
3b18152c3
|
1292 |
cfq_mark_cfqq_prio_changed(cfqq); |
22e2c507c
|
1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 |
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 * |
3b18152c3
|
1314 |
cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio, |
8267e268e
|
1315 |
gfp_t gfp_mask) |
22e2c507c
|
1316 1317 1318 1319 1320 |
{ const int hashval = hash_long(key, CFQ_QHASH_SHIFT); struct cfq_queue *cfqq, *new_cfqq = NULL; retry: |
3b18152c3
|
1321 |
cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval); |
22e2c507c
|
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 |
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; |
3b18152c3
|
1355 1356 1357 |
cfq_mark_cfqq_idle_window(cfqq); cfq_mark_cfqq_prio_changed(cfqq); cfq_init_prio_data(cfqq); |
22e2c507c
|
1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 |
} if (new_cfqq) kmem_cache_free(cfq_pool, new_cfqq); atomic_inc(&cfqq->ref); out: WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); return cfqq; } |
1da177e4c
|
1368 1369 1370 1371 1372 1373 1374 |
/* * 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 * |
8267e268e
|
1375 |
cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask) |
1da177e4c
|
1376 |
{ |
22e2c507c
|
1377 |
struct io_context *ioc = NULL; |
1da177e4c
|
1378 |
struct cfq_io_context *cic; |
1da177e4c
|
1379 |
|
22e2c507c
|
1380 |
might_sleep_if(gfp_mask & __GFP_WAIT); |
1da177e4c
|
1381 |
|
22e2c507c
|
1382 |
ioc = get_io_context(gfp_mask); |
1da177e4c
|
1383 1384 1385 1386 |
if (!ioc) return NULL; if ((cic = ioc->cic) == NULL) { |
22e2c507c
|
1387 |
cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4c
|
1388 1389 1390 |
if (cic == NULL) goto err; |
22e2c507c
|
1391 1392 1393 1394 |
/* * manually increment generic io_context usage count, it * cannot go away since we are already holding one ref to it */ |
1da177e4c
|
1395 |
ioc->cic = cic; |
22e2c507c
|
1396 |
ioc->set_ioprio = cfq_ioc_set_ioprio; |
1da177e4c
|
1397 |
cic->ioc = ioc; |
22e2c507c
|
1398 1399 |
cic->key = cfqd; atomic_inc(&cfqd->ref); |
1da177e4c
|
1400 1401 |
} else { struct cfq_io_context *__cic; |
1da177e4c
|
1402 1403 |
/* |
22e2c507c
|
1404 |
* the first cic on the list is actually the head itself |
1da177e4c
|
1405 |
*/ |
22e2c507c
|
1406 |
if (cic->key == cfqd) |
1da177e4c
|
1407 1408 1409 1410 1411 1412 1413 |
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 */ |
1da177e4c
|
1414 1415 1416 1417 1418 |
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 */ |
22e2c507c
|
1419 |
if (__cic->key == cfqd) { |
1da177e4c
|
1420 |
cic = __cic; |
1da177e4c
|
1421 1422 1423 |
goto out; } } |
1da177e4c
|
1424 1425 1426 1427 1428 |
/* * nope, process doesn't have a cic assoicated with this * cfqq yet. get a new one and add to list */ |
22e2c507c
|
1429 |
__cic = cfq_alloc_io_context(cfqd, gfp_mask); |
1da177e4c
|
1430 1431 1432 1433 |
if (__cic == NULL) goto err; __cic->ioc = ioc; |
22e2c507c
|
1434 1435 |
__cic->key = cfqd; atomic_inc(&cfqd->ref); |
1da177e4c
|
1436 |
list_add(&__cic->list, &cic->list); |
1da177e4c
|
1437 |
cic = __cic; |
1da177e4c
|
1438 1439 1440 |
} out: |
1da177e4c
|
1441 1442 1443 1444 1445 |
return cic; err: put_io_context(ioc); return NULL; } |
22e2c507c
|
1446 1447 |
static void cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) |
1da177e4c
|
1448 |
{ |
22e2c507c
|
1449 |
unsigned long elapsed, ttime; |
1da177e4c
|
1450 |
|
22e2c507c
|
1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 |
/* * 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 |
1da177e4c
|
1463 |
|
22e2c507c
|
1464 |
ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle); |
db3b5848e
|
1465 |
|
22e2c507c
|
1466 1467 1468 1469 |
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; } |
1da177e4c
|
1470 |
|
22e2c507c
|
1471 |
#define sample_valid(samples) ((samples) > 80) |
1da177e4c
|
1472 |
|
22e2c507c
|
1473 1474 1475 1476 1477 1478 1479 1480 |
/* * 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) { |
3b18152c3
|
1481 |
int enable_idle = cfq_cfqq_idle_window(cfqq); |
1da177e4c
|
1482 |
|
22e2c507c
|
1483 1484 1485 1486 1487 1488 1489 |
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; |
1da177e4c
|
1490 |
} |
3b18152c3
|
1491 1492 1493 1494 |
if (enable_idle) cfq_mark_cfqq_idle_window(cfqq); else cfq_clear_cfqq_idle_window(cfqq); |
22e2c507c
|
1495 |
} |
1da177e4c
|
1496 |
|
22e2c507c
|
1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 |
/* * 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; |
3b18152c3
|
1516 |
if (!cfq_cfqq_wait_request(new_cfqq)) |
22e2c507c
|
1517 1518 1519 1520 1521 1522 |
return 0; /* * if it doesn't have slice left, forget it */ if (new_cfqq->slice_left < cfqd->cfq_slice_idle) return 0; |
3b18152c3
|
1523 |
if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) |
22e2c507c
|
1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 |
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; |
3b18152c3
|
1544 |
__cfq_slice_expired(cfqd, cfqq, 1); |
22e2c507c
|
1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 |
__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) { |
9c2c38a12
|
1569 |
struct cfq_io_context *cic; |
22e2c507c
|
1570 1571 |
cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); |
9c2c38a12
|
1572 1573 1574 1575 1576 1577 |
/* * 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; |
22e2c507c
|
1578 |
|
9c2c38a12
|
1579 |
cic = crq->io_context; |
22e2c507c
|
1580 |
|
9c2c38a12
|
1581 1582 1583 1584 |
cfq_update_io_thinktime(cfqd, cic); cfq_update_idle_window(cfqd, cfqq, cic); cic->last_queue = jiffies; |
22e2c507c
|
1585 1586 1587 1588 1589 1590 1591 |
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 */ |
3b18152c3
|
1592 1593 |
if (cfq_cfqq_wait_request(cfqq)) { cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507c
|
1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 |
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); |
3b18152c3
|
1604 |
cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507c
|
1605 1606 |
cfq_start_queueing(cfqd, cfqq); } |
1da177e4c
|
1607 |
} |
b4878f245
|
1608 |
static void cfq_insert_request(request_queue_t *q, struct request *rq) |
1da177e4c
|
1609 |
{ |
b4878f245
|
1610 |
struct cfq_data *cfqd = q->elevator->elevator_data; |
22e2c507c
|
1611 1612 1613 1614 |
struct cfq_rq *crq = RQ_DATA(rq); struct cfq_queue *cfqq = crq->cfq_queue; cfq_init_prio_data(cfqq); |
1da177e4c
|
1615 1616 |
cfq_add_crq_rb(crq); |
1da177e4c
|
1617 |
|
22e2c507c
|
1618 |
list_add_tail(&rq->queuelist, &cfqq->fifo); |
98b11471d
|
1619 |
if (rq_mergeable(rq)) |
22e2c507c
|
1620 |
cfq_add_crq_hash(cfqd, crq); |
22e2c507c
|
1621 |
cfq_crq_enqueued(cfqd, cfqq, crq); |
1da177e4c
|
1622 |
} |
1da177e4c
|
1623 1624 1625 |
static void cfq_completed_request(request_queue_t *q, struct request *rq) { struct cfq_rq *crq = RQ_DATA(rq); |
b4878f245
|
1626 1627 1628 1629 |
struct cfq_queue *cfqq = crq->cfq_queue; struct cfq_data *cfqd = cfqq->cfqd; const int sync = cfq_crq_is_sync(crq); unsigned long now; |
1da177e4c
|
1630 |
|
b4878f245
|
1631 |
now = jiffies; |
1da177e4c
|
1632 |
|
b4878f245
|
1633 1634 1635 1636 |
WARN_ON(!cfqd->rq_in_driver); WARN_ON(!cfqq->on_dispatch[sync]); cfqd->rq_in_driver--; cfqq->on_dispatch[sync]--; |
1da177e4c
|
1637 |
|
b4878f245
|
1638 1639 |
if (!cfq_class_idle(cfqq)) cfqd->last_end_request = now; |
3b18152c3
|
1640 |
|
b4878f245
|
1641 1642 1643 1644 1645 1646 1647 1648 1649 |
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); } |
1da177e4c
|
1650 |
} |
b4878f245
|
1651 1652 |
if (cfq_crq_is_sync(crq)) crq->io_context->last_end_request = now; |
1da177e4c
|
1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 |
} 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; } |
22e2c507c
|
1678 1679 1680 1681 1682 |
/* * 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) |
1da177e4c
|
1683 |
{ |
22e2c507c
|
1684 1685 |
const int ioprio_class = cfqq->ioprio_class; const int ioprio = cfqq->ioprio; |
1da177e4c
|
1686 |
|
22e2c507c
|
1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 |
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; } |
1da177e4c
|
1705 |
|
22e2c507c
|
1706 1707 1708 1709 |
/* * refile between round-robin lists if we moved the priority class */ if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) && |
3b18152c3
|
1710 |
cfq_cfqq_on_rr(cfqq)) |
22e2c507c
|
1711 1712 |
cfq_resort_rr_list(cfqq, 0); } |
1da177e4c
|
1713 |
|
22e2c507c
|
1714 1715 1716 1717 |
static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) { if (rw == READ || process_sync(task)) return task->pid; |
1da177e4c
|
1718 |
|
22e2c507c
|
1719 1720 |
return CFQ_KEY_ASYNC; } |
1da177e4c
|
1721 |
|
22e2c507c
|
1722 1723 1724 1725 |
static inline int __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct task_struct *task, int rw) { |
3b18152c3
|
1726 1727 |
#if 1 if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) && |
99f95e528
|
1728 |
!cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c3
|
1729 |
cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507c
|
1730 |
return ELV_MQUEUE_MUST; |
3b18152c3
|
1731 |
} |
1da177e4c
|
1732 |
|
22e2c507c
|
1733 |
return ELV_MQUEUE_MAY; |
3b18152c3
|
1734 |
#else |
22e2c507c
|
1735 1736 |
if (!cfqq || task->flags & PF_MEMALLOC) return ELV_MQUEUE_MAY; |
3b18152c3
|
1737 1738 |
if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) { if (cfq_cfqq_wait_request(cfqq)) |
22e2c507c
|
1739 |
return ELV_MQUEUE_MUST; |
1da177e4c
|
1740 |
|
22e2c507c
|
1741 1742 1743 1744 |
/* * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we * can quickly flood the queue with writes from a single task */ |
99f95e528
|
1745 |
if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) { |
3b18152c3
|
1746 |
cfq_mark_cfqq_must_alloc_slice(cfqq); |
22e2c507c
|
1747 |
return ELV_MQUEUE_MUST; |
1da177e4c
|
1748 |
} |
22e2c507c
|
1749 1750 |
return ELV_MQUEUE_MAY; |
1da177e4c
|
1751 |
} |
22e2c507c
|
1752 1753 1754 1755 1756 |
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; |
1da177e4c
|
1757 |
|
22e2c507c
|
1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 |
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 */ |
3b18152c3
|
1781 |
cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio); |
22e2c507c
|
1782 1783 1784 1785 1786 1787 1788 1789 |
if (cfqq) { cfq_init_prio_data(cfqq); cfq_prio_boost(cfqq); return __cfq_may_queue(cfqd, cfqq, tsk, rw); } return ELV_MQUEUE_MAY; |
1da177e4c
|
1790 1791 1792 1793 |
} static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) { |
22e2c507c
|
1794 |
struct cfq_data *cfqd = q->elevator->elevator_data; |
1da177e4c
|
1795 |
struct request_list *rl = &q->rq; |
1da177e4c
|
1796 |
|
22e2c507c
|
1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 |
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]); } |
1da177e4c
|
1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 |
} /* * 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; |
22e2c507c
|
1820 |
const int rw = rq_data_dir(rq); |
1da177e4c
|
1821 |
|
22e2c507c
|
1822 1823 |
BUG_ON(!cfqq->allocated[rw]); cfqq->allocated[rw]--; |
1da177e4c
|
1824 |
|
22e2c507c
|
1825 |
put_io_context(crq->io_context->ioc); |
1da177e4c
|
1826 1827 1828 |
mempool_free(crq, cfqd->crq_pool); rq->elevator_private = NULL; |
1da177e4c
|
1829 1830 1831 1832 1833 1834 |
cfq_check_waiters(q, cfqq); cfq_put_queue(cfqq); } } /* |
22e2c507c
|
1835 |
* Allocate cfq data structures associated with this request. |
1da177e4c
|
1836 |
*/ |
22e2c507c
|
1837 1838 |
static int cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, |
8267e268e
|
1839 |
gfp_t gfp_mask) |
1da177e4c
|
1840 1841 |
{ struct cfq_data *cfqd = q->elevator->elevator_data; |
3b18152c3
|
1842 |
struct task_struct *tsk = current; |
1da177e4c
|
1843 1844 |
struct cfq_io_context *cic; const int rw = rq_data_dir(rq); |
3b18152c3
|
1845 |
pid_t key = cfq_queue_pid(tsk, rw); |
22e2c507c
|
1846 |
struct cfq_queue *cfqq; |
1da177e4c
|
1847 1848 1849 1850 |
struct cfq_rq *crq; unsigned long flags; might_sleep_if(gfp_mask & __GFP_WAIT); |
3b18152c3
|
1851 |
cic = cfq_get_io_context(cfqd, key, gfp_mask); |
22e2c507c
|
1852 |
|
1da177e4c
|
1853 |
spin_lock_irqsave(q->queue_lock, flags); |
22e2c507c
|
1854 1855 1856 1857 |
if (!cic) goto queue_fail; if (!cic->cfqq) { |
3b18152c3
|
1858 |
cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask); |
22e2c507c
|
1859 1860 |
if (!cfqq) goto queue_fail; |
1da177e4c
|
1861 |
|
22e2c507c
|
1862 1863 1864 |
cic->cfqq = cfqq; } else cfqq = cic->cfqq; |
1da177e4c
|
1865 1866 |
cfqq->allocated[rw]++; |
3b18152c3
|
1867 |
cfq_clear_cfqq_must_alloc(cfqq); |
22e2c507c
|
1868 1869 |
cfqd->rq_starved = 0; atomic_inc(&cfqq->ref); |
1da177e4c
|
1870 |
spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4c
|
1871 1872 1873 1874 1875 1876 1877 1878 |
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; |
3b18152c3
|
1879 1880 1881 1882 1883 |
if (rw == READ || process_sync(tsk)) cfq_mark_crq_is_sync(crq); else cfq_clear_crq_is_sync(crq); |
1da177e4c
|
1884 |
rq->elevator_private = crq; |
1da177e4c
|
1885 1886 |
return 0; } |
1da177e4c
|
1887 1888 |
spin_lock_irqsave(q->queue_lock, flags); cfqq->allocated[rw]--; |
22e2c507c
|
1889 |
if (!(cfqq->allocated[0] + cfqq->allocated[1])) |
3b18152c3
|
1890 |
cfq_mark_cfqq_must_alloc(cfqq); |
1da177e4c
|
1891 |
cfq_put_queue(cfqq); |
22e2c507c
|
1892 1893 1894 1895 1896 1897 1898 1899 1900 |
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; |
3b18152c3
|
1901 |
cfq_schedule_dispatch(cfqd); |
1da177e4c
|
1902 1903 1904 |
spin_unlock_irqrestore(q->queue_lock, flags); return 1; } |
22e2c507c
|
1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 |
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 */ |
b4878f245
|
1956 |
if (!cfqd->busy_queues) { |
22e2c507c
|
1957 1958 1959 1960 1961 1962 1963 1964 1965 |
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)) { |
3b18152c3
|
1966 |
cfq_mark_cfqq_must_dispatch(cfqq); |
22e2c507c
|
1967 1968 1969 1970 1971 1972 |
goto out_kick; } } expire: cfq_slice_expired(cfqd, 0); out_kick: |
3b18152c3
|
1973 |
cfq_schedule_dispatch(cfqd); |
22e2c507c
|
1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 |
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 |
3b18152c3
|
1996 |
cfq_schedule_dispatch(cfqd); |
22e2c507c
|
1997 1998 1999 |
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); } |
3b18152c3
|
2000 2001 2002 2003 2004 2005 |
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); } |
22e2c507c
|
2006 |
|
1da177e4c
|
2007 2008 2009 2010 2011 2012 |
static void cfq_put_cfqd(struct cfq_data *cfqd) { request_queue_t *q = cfqd->queue; if (!atomic_dec_and_test(&cfqd->ref)) return; |
96c51ce94
|
2013 |
cfq_shutdown_timer_wq(cfqd); |
4fc207419
|
2014 |
blk_put_queue(q); |
96c51ce94
|
2015 |
|
1da177e4c
|
2016 2017 2018 2019 2020 2021 2022 2023 |
mempool_destroy(cfqd->crq_pool); kfree(cfqd->crq_hash); kfree(cfqd->cfq_hash); kfree(cfqd); } static void cfq_exit_queue(elevator_t *e) { |
22e2c507c
|
2024 |
struct cfq_data *cfqd = e->elevator_data; |
3b18152c3
|
2025 |
cfq_shutdown_timer_wq(cfqd); |
22e2c507c
|
2026 |
cfq_put_cfqd(cfqd); |
1da177e4c
|
2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 |
} 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)); |
22e2c507c
|
2039 2040 2041 2042 2043 2044 2045 |
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); |
1da177e4c
|
2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 |
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; |
35797132b
|
2068 |
atomic_inc(&q->refcnt); |
1da177e4c
|
2069 |
|
22e2c507c
|
2070 |
cfqd->max_queued = q->nr_requests / 4; |
1da177e4c
|
2071 |
q->nr_batching = cfq_queued; |
22e2c507c
|
2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 |
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); |
1da177e4c
|
2082 2083 2084 2085 |
atomic_set(&cfqd->ref, 1); cfqd->cfq_queued = cfq_queued; cfqd->cfq_quantum = cfq_quantum; |
22e2c507c
|
2086 2087 |
cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; |
1da177e4c
|
2088 2089 |
cfqd->cfq_back_max = cfq_back_max; cfqd->cfq_back_penalty = cfq_back_penalty; |
22e2c507c
|
2090 2091 2092 2093 2094 |
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; |
3b18152c3
|
2095 |
|
1da177e4c
|
2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 |
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; } |
1da177e4c
|
2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 |
/* * 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 ", 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; } |
1da177e4c
|
2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 |
#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); |
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|
2172 2173 |
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); |
1da177e4c
|
2174 2175 |
SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0); SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0); |
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|
2176 2177 2178 2179 2180 |
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); |
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2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 |
#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); |
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|
2200 2201 |
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); |
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|
2202 2203 |
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); |
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|
2204 2205 2206 2207 2208 |
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); |
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2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 |
#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, }; |
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2221 |
static struct cfq_fs_entry cfq_fifo_expire_sync_entry = { |
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|
2222 |
.attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR }, |
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|
2223 2224 |
.show = cfq_fifo_expire_sync_show, .store = cfq_fifo_expire_sync_store, |
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|
2225 |
}; |
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2226 |
static struct cfq_fs_entry cfq_fifo_expire_async_entry = { |
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2227 |
.attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR }, |
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|
2228 2229 |
.show = cfq_fifo_expire_async_show, .store = cfq_fifo_expire_async_store, |
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2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 |
}; 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, }; |
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|
2241 2242 2243 2244 |
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, |
1da177e4c
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2245 |
}; |
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2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 |
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, |
1da177e4c
|
2265 |
}; |
3b18152c3
|
2266 |
|
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2267 2268 2269 |
static struct attribute *default_attrs[] = { &cfq_quantum_entry.attr, &cfq_queued_entry.attr, |
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2270 2271 |
&cfq_fifo_expire_sync_entry.attr, &cfq_fifo_expire_async_entry.attr, |
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|
2272 2273 |
&cfq_back_max_entry.attr, &cfq_back_penalty_entry.attr, |
22e2c507c
|
2274 2275 2276 2277 2278 |
&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, |
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|
2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 |
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) |
6c1852a08
|
2291 |
return -EIO; |
1da177e4c
|
2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 |
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) |
6c1852a08
|
2304 |
return -EIO; |
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|
2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 |
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, |
b4878f245
|
2324 |
.elevator_dispatch_fn = cfq_dispatch_requests, |
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|
2325 |
.elevator_add_req_fn = cfq_insert_request, |
b4878f245
|
2326 |
.elevator_activate_req_fn = cfq_activate_request, |
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|
2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 |
.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; |
22e2c507c
|
2346 2347 2348 2349 2350 2351 2352 |
/* * could be 0 on HZ < 1000 setups */ if (!cfq_slice_async) cfq_slice_async = 1; if (!cfq_slice_idle) cfq_slice_idle = 1; |
1da177e4c
|
2353 2354 2355 2356 |
if (cfq_slab_setup()) return -ENOMEM; ret = elv_register(&iosched_cfq); |
22e2c507c
|
2357 2358 |
if (ret) cfq_slab_kill(); |
1da177e4c
|
2359 |
|
1da177e4c
|
2360 2361 2362 2363 2364 |
return ret; } static void __exit cfq_exit(void) { |
1da177e4c
|
2365 |
elv_unregister(&iosched_cfq); |
83521d3eb
|
2366 |
cfq_slab_kill(); |
1da177e4c
|
2367 2368 2369 2370 2371 2372 2373 2374 |
} module_init(cfq_init); module_exit(cfq_exit); MODULE_AUTHOR("Jens Axboe"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler"); |