| /* |
| * 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/module.h> |
| #include <linux/blkdev.h> |
| #include <linux/elevator.h> |
| #include <linux/hash.h> |
| #include <linux/rbtree.h> |
| #include <linux/ioprio.h> |
| |
| /* |
| * tunables |
| */ |
| static const int cfq_quantum = 4; /* max queue in one round of service */ |
| 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 */ |
| |
| static const int cfq_slice_sync = HZ / 10; |
| static int cfq_slice_async = HZ / 25; |
| static const int cfq_slice_async_rq = 2; |
| static int cfq_slice_idle = HZ / 125; |
| |
| #define CFQ_IDLE_GRACE (HZ / 10) |
| #define CFQ_SLICE_SCALE (5) |
| |
| #define CFQ_KEY_ASYNC (0) |
| |
| /* |
| * 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) |
| |
| #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) |
| |
| #define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private) |
| #define RQ_CFQQ(rq) ((rq)->elevator_private2) |
| |
| static kmem_cache_t *cfq_pool; |
| static kmem_cache_t *cfq_ioc_pool; |
| |
| static DEFINE_PER_CPU(unsigned long, ioc_count); |
| static struct completion *ioc_gone; |
| |
| #define CFQ_PRIO_LISTS IOPRIO_BE_NR |
| #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE) |
| #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]) |
| |
| #define sample_valid(samples) ((samples) > 80) |
| |
| /* |
| * Per block device queue structure |
| */ |
| struct cfq_data { |
| 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; |
| |
| /* |
| * cfqq lookup hash |
| */ |
| struct hlist_head *cfq_hash; |
| |
| int rq_in_driver; |
| int hw_tag; |
| |
| /* |
| * 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; |
| |
| /* |
| * tunables, see top of file |
| */ |
| unsigned int cfq_quantum; |
| 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; |
| |
| struct list_head cic_list; |
| }; |
| |
| /* |
| * 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; |
| /* member of the rr/busy/cur/idle cfqd list */ |
| 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 request *next_rq; |
| /* requests queued in sort_list */ |
| int queued[2]; |
| /* currently allocated requests */ |
| int allocated[2]; |
| /* pending metadata requests */ |
| int meta_pending; |
| /* fifo list of requests in sort_list */ |
| struct list_head fifo; |
| |
| unsigned long slice_start; |
| unsigned long slice_end; |
| unsigned long slice_left; |
| |
| /* 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; |
| }; |
| |
| 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_queue_new, |
| }; |
| |
| #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(queue_new); |
| #undef CFQ_CFQQ_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 request *); |
| static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); |
| |
| /* |
| * 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->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; |
| } |
| |
| static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) |
| { |
| if (rw == READ || rw == WRITE_SYNC) |
| return task->pid; |
| |
| return CFQ_KEY_ASYNC; |
| } |
| |
| /* |
| * Lifted from AS - choose which of rq1 and rq2 that is best served now. |
| * We choose the request that is closest to the head right now. Distance |
| * behind the head is penalized and only allowed to a certain extent. |
| */ |
| static struct request * |
| cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2) |
| { |
| sector_t last, s1, s2, d1 = 0, d2 = 0; |
| unsigned long back_max; |
| #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */ |
| #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ |
| unsigned wrap = 0; /* bit mask: requests behind the disk head? */ |
| |
| if (rq1 == NULL || rq1 == rq2) |
| return rq2; |
| if (rq2 == NULL) |
| return rq1; |
| |
| if (rq_is_sync(rq1) && !rq_is_sync(rq2)) |
| return rq1; |
| else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) |
| return rq2; |
| if (rq_is_meta(rq1) && !rq_is_meta(rq2)) |
| return rq1; |
| else if (rq_is_meta(rq2) && !rq_is_meta(rq1)) |
| return rq2; |
| |
| s1 = rq1->sector; |
| s2 = rq2->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 |
| wrap |= CFQ_RQ1_WRAP; |
| |
| if (s2 >= last) |
| d2 = s2 - last; |
| else if (s2 + back_max >= last) |
| d2 = (last - s2) * cfqd->cfq_back_penalty; |
| else |
| wrap |= CFQ_RQ2_WRAP; |
| |
| /* Found required data */ |
| |
| /* |
| * By doing switch() on the bit mask "wrap" we avoid having to |
| * check two variables for all permutations: --> faster! |
| */ |
| switch (wrap) { |
| case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ |
| if (d1 < d2) |
| return rq1; |
| else if (d2 < d1) |
| return rq2; |
| else { |
| if (s1 >= s2) |
| return rq1; |
| else |
| return rq2; |
| } |
| |
| case CFQ_RQ2_WRAP: |
| return rq1; |
| case CFQ_RQ1_WRAP: |
| return rq2; |
| case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ |
| default: |
| /* |
| * Since both rqs are wrapped, |
| * start with the one that's further behind head |
| * (--> only *one* back seek required), |
| * since back seek takes more time than forward. |
| */ |
| if (s1 <= s2) |
| return rq1; |
| else |
| return rq2; |
| } |
| } |
| |
| /* |
| * would be nice to take fifo expire time into account as well |
| */ |
| static struct request * |
| cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| struct request *last) |
| { |
| struct rb_node *rbnext = rb_next(&last->rb_node); |
| struct rb_node *rbprev = rb_prev(&last->rb_node); |
| struct request *next = NULL, *prev = NULL; |
| |
| BUG_ON(RB_EMPTY_NODE(&last->rb_node)); |
| |
| if (rbprev) |
| prev = rb_entry_rq(rbprev); |
| |
| if (rbnext) |
| next = rb_entry_rq(rbnext); |
| else { |
| rbnext = rb_first(&cfqq->sort_list); |
| if (rbnext && rbnext != &last->rb_node) |
| next = rb_entry_rq(rbnext); |
| } |
| |
| return cfq_choose_req(cfqd, next, prev); |
| } |
| |
| static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) |
| { |
| struct cfq_data *cfqd = cfqq->cfqd; |
| struct list_head *list; |
| |
| 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 this queue was preempted or is new (never been serviced), let |
| * it be added first for fairness but beind other new queues. |
| * Otherwise, just add to the back of the list. |
| */ |
| if (preempted || cfq_cfqq_queue_new(cfqq)) { |
| struct list_head *n = list; |
| struct cfq_queue *__cfqq; |
| |
| while (n->next != list) { |
| __cfqq = list_entry_cfqq(n->next); |
| if (!cfq_cfqq_queue_new(__cfqq)) |
| break; |
| |
| n = n->next; |
| } |
| |
| list = n; |
| } |
| |
| list_add_tail(&cfqq->cfq_list, list); |
| } |
| |
| /* |
| * 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_del_init(&cfqq->cfq_list); |
| |
| BUG_ON(!cfqd->busy_queues); |
| cfqd->busy_queues--; |
| } |
| |
| /* |
| * rb tree support functions |
| */ |
| static inline void cfq_del_rq_rb(struct request *rq) |
| { |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| struct cfq_data *cfqd = cfqq->cfqd; |
| const int sync = rq_is_sync(rq); |
| |
| BUG_ON(!cfqq->queued[sync]); |
| cfqq->queued[sync]--; |
| |
| elv_rb_del(&cfqq->sort_list, rq); |
| |
| if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) |
| cfq_del_cfqq_rr(cfqd, cfqq); |
| } |
| |
| static void cfq_add_rq_rb(struct request *rq) |
| { |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| struct cfq_data *cfqd = cfqq->cfqd; |
| struct request *__alias; |
| |
| cfqq->queued[rq_is_sync(rq)]++; |
| |
| /* |
| * looks a little odd, but the first insert might return an alias. |
| * if that happens, put the alias on the dispatch list |
| */ |
| while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) |
| cfq_dispatch_insert(cfqd->queue, __alias); |
| } |
| |
| static inline void |
| cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) |
| { |
| elv_rb_del(&cfqq->sort_list, rq); |
| cfqq->queued[rq_is_sync(rq)]--; |
| cfq_add_rq_rb(rq); |
| } |
| |
| static struct request * |
| cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio) |
| { |
| struct task_struct *tsk = current; |
| pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio)); |
| struct cfq_queue *cfqq; |
| |
| cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); |
| if (cfqq) { |
| sector_t sector = bio->bi_sector + bio_sectors(bio); |
| |
| return elv_rb_find(&cfqq->sort_list, sector); |
| } |
| |
| 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++; |
| |
| /* |
| * If the depth is larger 1, it really could be queueing. But lets |
| * make the mark a little higher - idling could still be good for |
| * low queueing, and a low queueing number could also just indicate |
| * a SCSI mid layer like behaviour where limit+1 is often seen. |
| */ |
| if (!cfqd->hw_tag && cfqd->rq_in_driver > 4) |
| cfqd->hw_tag = 1; |
| } |
| |
| 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_queue *cfqq = RQ_CFQQ(rq); |
| |
| if (cfqq->next_rq == rq) |
| cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); |
| |
| list_del_init(&rq->queuelist); |
| cfq_del_rq_rb(rq); |
| |
| if (rq_is_meta(rq)) { |
| WARN_ON(!cfqq->meta_pending); |
| cfqq->meta_pending--; |
| } |
| } |
| |
| 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; |
| |
| __rq = cfq_find_rq_fmerge(cfqd, bio); |
| if (__rq && elv_rq_merge_ok(__rq, bio)) { |
| *req = __rq; |
| return ELEVATOR_FRONT_MERGE; |
| } |
| |
| return ELEVATOR_NO_MERGE; |
| } |
| |
| static void cfq_merged_request(request_queue_t *q, struct request *req, |
| int type) |
| { |
| if (type == ELEVATOR_FRONT_MERGE) { |
| struct cfq_queue *cfqq = RQ_CFQQ(req); |
| |
| cfq_reposition_rq_rb(cfqq, req); |
| } |
| } |
| |
| static void |
| cfq_merged_requests(request_queue_t *q, struct request *rq, |
| struct request *next) |
| { |
| /* |
| * 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); |
| } |
| |
| cfqd->active_queue = 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)) |
| cfq_schedule_dispatch(cfqd); |
| |
| cfq_clear_cfqq_must_dispatch(cfqq); |
| cfq_clear_cfqq_wait_request(cfqq); |
| cfq_clear_cfqq_queue_new(cfqq); |
| |
| /* |
| * store what was left of this slice, if the queue idled out |
| * or was preempted |
| */ |
| if (time_after(cfqq->slice_end, now)) |
| cfqq->slice_left = cfqq->slice_end - now; |
| 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) |
| __cfq_slice_expired(cfqd, cfqq, preempted); |
| } |
| |
| /* |
| * 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 = NULL; |
| |
| if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) { |
| /* |
| * 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 |
| */ |
| cfqq = list_entry_cfqq(cfqd->cur_rr.next); |
| } else if (!list_empty(&cfqd->busy_rr)) { |
| /* |
| * If no new queues are available, check if the busy list has |
| * some before falling back to idle io. |
| */ |
| cfqq = list_entry_cfqq(cfqd->busy_rr.next); |
| } else if (!list_empty(&cfqd->idle_rr)) { |
| /* |
| * 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 |
| */ |
| 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; |
| } |
| |
| #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024)) |
| |
| static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| |
| { |
| struct cfq_io_context *cic; |
| unsigned long sl; |
| |
| WARN_ON(!RB_EMPTY_ROOT(&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 |
| */ |
| cic = cfqd->active_cic; |
| if (!cic || !cic->ioc->task) |
| return 0; |
| |
| cfq_mark_cfqq_must_dispatch(cfqq); |
| cfq_mark_cfqq_wait_request(cfqq); |
| |
| sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle); |
| |
| /* |
| * we don't want to idle for seeks, but we do want to allow |
| * fair distribution of slice time for a process doing back-to-back |
| * seeks. so allow a little bit of time for him to submit a new rq |
| */ |
| if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) |
| sl = min(sl, msecs_to_jiffies(2)); |
| |
| mod_timer(&cfqd->idle_slice_timer, jiffies + sl); |
| return 1; |
| } |
| |
| static void cfq_dispatch_insert(request_queue_t *q, struct request *rq) |
| { |
| struct cfq_data *cfqd = q->elevator->elevator_data; |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| |
| cfq_remove_request(rq); |
| cfqq->on_dispatch[rq_is_sync(rq)]++; |
| elv_dispatch_sort(q, rq); |
| |
| rq = list_entry(q->queue_head.prev, struct request, queuelist); |
| cfqd->last_sector = rq->sector + rq->nr_sectors; |
| } |
| |
| /* |
| * return expired entry, or NULL to just start from scratch in rbtree |
| */ |
| static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq) |
| { |
| struct cfq_data *cfqd = cfqq->cfqd; |
| struct request *rq; |
| int fifo; |
| |
| if (cfq_cfqq_fifo_expire(cfqq)) |
| return NULL; |
| if (list_empty(&cfqq->fifo)) |
| return NULL; |
| |
| fifo = cfq_cfqq_class_sync(cfqq); |
| rq = rq_entry_fifo(cfqq->fifo.next); |
| |
| if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { |
| cfq_mark_cfqq_fifo_expire(cfqq); |
| return rq; |
| } |
| |
| 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) |
| { |
| unsigned long now = jiffies; |
| struct cfq_queue *cfqq; |
| |
| cfqq = cfqd->active_queue; |
| if (!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_ROOT(&cfqq->sort_list)) |
| goto keep_queue; |
| else if (cfq_cfqq_dispatched(cfqq)) { |
| cfqq = NULL; |
| goto keep_queue; |
| } else if (cfq_cfqq_class_sync(cfqq)) { |
| 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_ROOT(&cfqq->sort_list)); |
| |
| do { |
| struct request *rq; |
| |
| /* |
| * follow expired path, else get first next available |
| */ |
| if ((rq = cfq_check_fifo(cfqq)) == NULL) |
| rq = cfqq->next_rq; |
| |
| /* |
| * finally, insert request into driver dispatch list |
| */ |
| cfq_dispatch_insert(cfqd->queue, rq); |
| |
| cfqd->dispatch_slice++; |
| dispatched++; |
| |
| if (!cfqd->active_cic) { |
| atomic_inc(&RQ_CIC(rq)->ioc->refcount); |
| cfqd->active_cic = RQ_CIC(rq); |
| } |
| |
| if (RB_EMPTY_ROOT(&cfqq->sort_list)) |
| break; |
| |
| } while (dispatched < max_dispatch); |
| |
| /* |
| * if slice end isn't set yet, set it. |
| */ |
| 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_cfqq_idle_window(cfqq)) |
| cfq_slice_expired(cfqd, 0); |
| |
| return dispatched; |
| } |
| |
| static int |
| cfq_forced_dispatch_cfqqs(struct list_head *list) |
| { |
| struct cfq_queue *cfqq, *next; |
| int dispatched; |
| |
| dispatched = 0; |
| list_for_each_entry_safe(cfqq, next, list, cfq_list) { |
| while (cfqq->next_rq) { |
| cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); |
| 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 |
| cfq_dispatch_requests(request_queue_t *q, int force) |
| { |
| struct cfq_data *cfqd = q->elevator->elevator_data; |
| struct cfq_queue *cfqq, *prev_cfqq; |
| int dispatched; |
| |
| if (!cfqd->busy_queues) |
| return 0; |
| |
| if (unlikely(force)) |
| return cfq_forced_dispatch(cfqd); |
| |
| dispatched = 0; |
| prev_cfqq = NULL; |
| while ((cfqq = cfq_select_queue(cfqd)) != NULL) { |
| int max_dispatch; |
| |
| /* |
| * Don't repeat dispatch from the previous queue. |
| */ |
| if (prev_cfqq == cfqq) |
| break; |
| |
| cfq_clear_cfqq_must_dispatch(cfqq); |
| cfq_clear_cfqq_wait_request(cfqq); |
| del_timer(&cfqd->idle_slice_timer); |
| |
| max_dispatch = cfqd->cfq_quantum; |
| if (cfq_class_idle(cfqq)) |
| max_dispatch = 1; |
| |
| dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); |
| |
| /* |
| * If the dispatch cfqq has idling enabled and is still |
| * the active queue, break out. |
| */ |
| if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue) |
| break; |
| |
| prev_cfqq = cfqq; |
| } |
| |
| return dispatched; |
| } |
| |
| /* |
| * task holds one reference to the queue, dropped when task exits. each rq |
| * in-flight on this queue also holds a reference, dropped when rq 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); |
| |
| /* |
| * 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 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; |
| struct cfq_queue *__cfqq; |
| |
| hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) { |
| const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio); |
| |
| if (__cfqq->key == key && (__p == prio || !prio)) |
| 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 io_context *ioc) |
| { |
| struct cfq_io_context *__cic; |
| struct rb_node *n; |
| int freed = 0; |
| |
| while ((n = rb_first(&ioc->cic_root)) != NULL) { |
| __cic = rb_entry(n, struct cfq_io_context, rb_node); |
| rb_erase(&__cic->rb_node, &ioc->cic_root); |
| kmem_cache_free(cfq_ioc_pool, __cic); |
| freed++; |
| } |
| |
| elv_ioc_count_mod(ioc_count, -freed); |
| |
| if (ioc_gone && !elv_ioc_count_read(ioc_count)) |
| complete(ioc_gone); |
| } |
| |
| static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) |
| { |
| if (unlikely(cfqq == cfqd->active_queue)) |
| __cfq_slice_expired(cfqd, cfqq, 0); |
| |
| cfq_put_queue(cfqq); |
| } |
| |
| static void __cfq_exit_single_io_context(struct cfq_data *cfqd, |
| struct cfq_io_context *cic) |
| { |
| list_del_init(&cic->queue_list); |
| smp_wmb(); |
| cic->key = NULL; |
| |
| if (cic->cfqq[ASYNC]) { |
| cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); |
| cic->cfqq[ASYNC] = NULL; |
| } |
| |
| if (cic->cfqq[SYNC]) { |
| cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); |
| cic->cfqq[SYNC] = NULL; |
| } |
| } |
| |
| |
| /* |
| * Called with interrupts disabled |
| */ |
| static void cfq_exit_single_io_context(struct cfq_io_context *cic) |
| { |
| struct cfq_data *cfqd = cic->key; |
| |
| if (cfqd) { |
| request_queue_t *q = cfqd->queue; |
| |
| spin_lock_irq(q->queue_lock); |
| __cfq_exit_single_io_context(cfqd, cic); |
| spin_unlock_irq(q->queue_lock); |
| } |
| } |
| |
| static void cfq_exit_io_context(struct io_context *ioc) |
| { |
| struct cfq_io_context *__cic; |
| struct rb_node *n; |
| |
| /* |
| * put the reference this task is holding to the various queues |
| */ |
| |
| n = rb_first(&ioc->cic_root); |
| while (n != NULL) { |
| __cic = rb_entry(n, struct cfq_io_context, rb_node); |
| |
| cfq_exit_single_io_context(__cic); |
| n = rb_next(n); |
| } |
| } |
| |
| static struct cfq_io_context * |
| cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) |
| { |
| struct cfq_io_context *cic; |
| |
| cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node); |
| if (cic) { |
| memset(cic, 0, sizeof(*cic)); |
| cic->last_end_request = jiffies; |
| INIT_LIST_HEAD(&cic->queue_list); |
| cic->dtor = cfq_free_io_context; |
| cic->exit = cfq_exit_io_context; |
| elv_ioc_count_inc(ioc_count); |
| } |
| |
| 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_io_context *cic) |
| { |
| struct cfq_data *cfqd = cic->key; |
| struct cfq_queue *cfqq; |
| |
| if (unlikely(!cfqd)) |
| return; |
| |
| spin_lock(cfqd->queue->queue_lock); |
| |
| cfqq = cic->cfqq[ASYNC]; |
| if (cfqq) { |
| struct cfq_queue *new_cfqq; |
| new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task, |
| GFP_ATOMIC); |
| if (new_cfqq) { |
| cic->cfqq[ASYNC] = new_cfqq; |
| cfq_put_queue(cfqq); |
| } |
| } |
| |
| cfqq = cic->cfqq[SYNC]; |
| if (cfqq) |
| cfq_mark_cfqq_prio_changed(cfqq); |
| |
| spin_unlock(cfqd->queue->queue_lock); |
| } |
| |
| static void cfq_ioc_set_ioprio(struct io_context *ioc) |
| { |
| struct cfq_io_context *cic; |
| struct rb_node *n; |
| |
| ioc->ioprio_changed = 0; |
| |
| n = rb_first(&ioc->cic_root); |
| while (n != NULL) { |
| cic = rb_entry(n, struct cfq_io_context, rb_node); |
| |
| changed_ioprio(cic); |
| n = rb_next(n); |
| } |
| } |
| |
| static struct cfq_queue * |
| cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, |
| gfp_t gfp_mask) |
| { |
| const int hashval = hash_long(key, CFQ_QHASH_SHIFT); |
| struct cfq_queue *cfqq, *new_cfqq = NULL; |
| unsigned short ioprio; |
| |
| retry: |
| ioprio = tsk->ioprio; |
| 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) { |
| /* |
| * Inform the allocator of the fact that we will |
| * just repeat this allocation if it fails, to allow |
| * the allocator to do whatever it needs to attempt to |
| * free memory. |
| */ |
| spin_unlock_irq(cfqd->queue->queue_lock); |
| new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node); |
| spin_lock_irq(cfqd->queue->queue_lock); |
| goto retry; |
| } else { |
| cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node); |
| if (!cfqq) |
| goto out; |
| } |
| |
| memset(cfqq, 0, sizeof(*cfqq)); |
| |
| INIT_HLIST_NODE(&cfqq->cfq_hash); |
| INIT_LIST_HEAD(&cfqq->cfq_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; |
| /* |
| * 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_mark_cfqq_queue_new(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; |
| } |
| |
| static void |
| cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) |
| { |
| WARN_ON(!list_empty(&cic->queue_list)); |
| rb_erase(&cic->rb_node, &ioc->cic_root); |
| kmem_cache_free(cfq_ioc_pool, cic); |
| elv_ioc_count_dec(ioc_count); |
| } |
| |
| static struct cfq_io_context * |
| cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc) |
| { |
| struct rb_node *n; |
| struct cfq_io_context *cic; |
| void *k, *key = cfqd; |
| |
| restart: |
| n = ioc->cic_root.rb_node; |
| while (n) { |
| cic = rb_entry(n, struct cfq_io_context, rb_node); |
| /* ->key must be copied to avoid race with cfq_exit_queue() */ |
| k = cic->key; |
| if (unlikely(!k)) { |
| cfq_drop_dead_cic(ioc, cic); |
| goto restart; |
| } |
| |
| if (key < k) |
| n = n->rb_left; |
| else if (key > k) |
| n = n->rb_right; |
| else |
| return cic; |
| } |
| |
| return NULL; |
| } |
| |
| static inline void |
| cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, |
| struct cfq_io_context *cic) |
| { |
| struct rb_node **p; |
| struct rb_node *parent; |
| struct cfq_io_context *__cic; |
| void *k; |
| |
| cic->ioc = ioc; |
| cic->key = cfqd; |
| |
| restart: |
| parent = NULL; |
| p = &ioc->cic_root.rb_node; |
| while (*p) { |
| parent = *p; |
| __cic = rb_entry(parent, struct cfq_io_context, rb_node); |
| /* ->key must be copied to avoid race with cfq_exit_queue() */ |
| k = __cic->key; |
| if (unlikely(!k)) { |
| cfq_drop_dead_cic(ioc, __cic); |
| goto restart; |
| } |
| |
| if (cic->key < k) |
| p = &(*p)->rb_left; |
| else if (cic->key > k) |
| p = &(*p)->rb_right; |
| else |
| BUG(); |
| } |
| |
| rb_link_node(&cic->rb_node, parent, p); |
| rb_insert_color(&cic->rb_node, &ioc->cic_root); |
| |
| spin_lock_irq(cfqd->queue->queue_lock); |
| list_add(&cic->queue_list, &cfqd->cic_list); |
| spin_unlock_irq(cfqd->queue->queue_lock); |
| } |
| |
| /* |
| * 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. |
| */ |
| static struct cfq_io_context * |
| cfq_get_io_context(struct cfq_data *cfqd, 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, cfqd->queue->node); |
| if (!ioc) |
| return NULL; |
| |
| cic = cfq_cic_rb_lookup(cfqd, ioc); |
| if (cic) |
| goto out; |
| |
| cic = cfq_alloc_io_context(cfqd, gfp_mask); |
| if (cic == NULL) |
| goto err; |
| |
| cfq_cic_link(cfqd, ioc, cic); |
| out: |
| smp_read_barrier_depends(); |
| if (unlikely(ioc->ioprio_changed)) |
| cfq_ioc_set_ioprio(ioc); |
| |
| 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; |
| } |
| |
| static void |
| cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, |
| struct request *rq) |
| { |
| sector_t sdist; |
| u64 total; |
| |
| if (cic->last_request_pos < rq->sector) |
| sdist = rq->sector - cic->last_request_pos; |
| else |
| sdist = cic->last_request_pos - rq->sector; |
| |
| /* |
| * Don't allow the seek distance to get too large from the |
| * odd fragment, pagein, etc |
| */ |
| if (cic->seek_samples <= 60) /* second&third seek */ |
| sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024); |
| else |
| sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64); |
| |
| cic->seek_samples = (7*cic->seek_samples + 256) / 8; |
| cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8; |
| total = cic->seek_total + (cic->seek_samples/2); |
| do_div(total, cic->seek_samples); |
| cic->seek_mean = (sector_t)total; |
| } |
| |
| /* |
| * 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 || |
| (cfqd->hw_tag && CIC_SEEKY(cic))) |
| 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 request *rq) |
| { |
| struct cfq_queue *cfqq = cfqd->active_queue; |
| |
| if (cfq_class_idle(new_cfqq)) |
| return 0; |
| |
| if (!cfqq) |
| return 0; |
| |
| 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 the new request is sync, but the currently running queue is |
| * not, let the sync request have priority. |
| */ |
| if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) |
| return 1; |
| /* |
| * So both queues are sync. Let the new request get disk time if |
| * it's a metadata request and the current queue is doing regular IO. |
| */ |
| if (rq_is_meta(rq) && !cfqq->meta_pending) |
| 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) |
| { |
| cfq_slice_expired(cfqd, 1); |
| |
| if (!cfqq->slice_left) |
| cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2; |
| |
| /* |
| * Put the new queue at the front of the of the current list, |
| * so we know that it will be selected next. |
| */ |
| BUG_ON(!cfq_cfqq_on_rr(cfqq)); |
| list_move(&cfqq->cfq_list, &cfqd->cur_rr); |
| |
| cfqq->slice_end = cfqq->slice_left + jiffies; |
| } |
| |
| /* |
| * Called when a new fs request (rq) is added (to cfqq). Check if there's |
| * something we should do about it |
| */ |
| static void |
| cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, |
| struct request *rq) |
| { |
| struct cfq_io_context *cic = RQ_CIC(rq); |
| |
| if (rq_is_meta(rq)) |
| cfqq->meta_pending++; |
| |
| /* |
| * check if this request is a better next-serve candidate)) { |
| */ |
| cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq); |
| BUG_ON(!cfqq->next_rq); |
| |
| /* |
| * we never wait for an async request and we don't allow preemption |
| * of an async request. so just return early |
| */ |
| if (!rq_is_sync(rq)) { |
| /* |
| * sync process issued an async request, if it's waiting |
| * then expire it and kick rq handling. |
| */ |
| if (cic == cfqd->active_cic && |
| del_timer(&cfqd->idle_slice_timer)) { |
| cfq_slice_expired(cfqd, 0); |
| blk_start_queueing(cfqd->queue); |
| } |
| return; |
| } |
| |
| cfq_update_io_thinktime(cfqd, cic); |
| cfq_update_io_seektime(cfqd, cic, rq); |
| cfq_update_idle_window(cfqd, cfqq, cic); |
| |
| cic->last_queue = jiffies; |
| cic->last_request_pos = rq->sector + rq->nr_sectors; |
| |
| 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); |
| blk_start_queueing(cfqd->queue); |
| } |
| } else if (cfq_should_preempt(cfqd, cfqq, rq)) { |
| /* |
| * 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); |
| blk_start_queueing(cfqd->queue); |
| } |
| } |
| |
| static void cfq_insert_request(request_queue_t *q, struct request *rq) |
| { |
| struct cfq_data *cfqd = q->elevator->elevator_data; |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| |
| cfq_init_prio_data(cfqq); |
| |
| cfq_add_rq_rb(rq); |
| |
| if (!cfq_cfqq_on_rr(cfqq)) |
| cfq_add_cfqq_rr(cfqd, cfqq); |
| |
| list_add_tail(&rq->queuelist, &cfqq->fifo); |
| |
| cfq_rq_enqueued(cfqd, cfqq, rq); |
| } |
| |
| static void cfq_completed_request(request_queue_t *q, struct request *rq) |
| { |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| struct cfq_data *cfqd = cfqq->cfqd; |
| const int sync = rq_is_sync(rq); |
| 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) && cfq_cfqq_on_rr(cfqq)) |
| cfq_resort_rr_list(cfqq, 0); |
| |
| if (sync) |
| RQ_CIC(rq)->last_end_request = now; |
| |
| /* |
| * If this is the active queue, check if it needs to be expired, |
| * or if we want to idle in case it has no pending requests. |
| */ |
| if (cfqd->active_queue == cfqq) { |
| if (time_after(now, cfqq->slice_end)) |
| cfq_slice_expired(cfqd, 0); |
| else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) { |
| if (!cfq_arm_slice_timer(cfqd, cfqq)) |
| cfq_schedule_dispatch(cfqd); |
| } |
| } |
| } |
| |
| /* |
| * 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 int __cfq_may_queue(struct cfq_queue *cfqq) |
| { |
| 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; |
| } |
| |
| static int cfq_may_queue(request_queue_t *q, int rw) |
| { |
| 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(cfqq); |
| } |
| |
| return ELV_MQUEUE_MAY; |
| } |
| |
| /* |
| * queue lock held here |
| */ |
| static void cfq_put_request(request_queue_t *q, struct request *rq) |
| { |
| struct cfq_queue *cfqq = RQ_CFQQ(rq); |
| |
| if (cfqq) { |
| const int rw = rq_data_dir(rq); |
| |
| BUG_ON(!cfqq->allocated[rw]); |
| cfqq->allocated[rw]--; |
| |
| put_io_context(RQ_CIC(rq)->ioc); |
| |
| rq->elevator_private = NULL; |
| rq->elevator_private2 = NULL; |
| |
| cfq_put_queue(cfqq); |
| } |
| } |
| |
| /* |
| * Allocate cfq data structures associated with this request. |
| */ |
| static int |
| cfq_set_request(request_queue_t *q, struct request *rq, 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; |
| unsigned long flags; |
| int is_sync = key != CFQ_KEY_ASYNC; |
| |
| might_sleep_if(gfp_mask & __GFP_WAIT); |
| |
| cic = cfq_get_io_context(cfqd, gfp_mask); |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| |
| if (!cic) |
| goto queue_fail; |
| |
| if (!cic->cfqq[is_sync]) { |
| cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask); |
| if (!cfqq) |
| goto queue_fail; |
| |
| cic->cfqq[is_sync] = cfqq; |
| } else |
| cfqq = cic->cfqq[is_sync]; |
| |
| cfqq->allocated[rw]++; |
| cfq_clear_cfqq_must_alloc(cfqq); |
| atomic_inc(&cfqq->ref); |
| |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| rq->elevator_private = cic; |
| rq->elevator_private2 = cfqq; |
| return 0; |
| |
| queue_fail: |
| if (cic) |
| put_io_context(cic->ioc); |
| |
| 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; |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_start_queueing(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) |
| goto out_cont; |
| |
| /* |
| * not expired and it has a request pending, let it dispatch |
| */ |
| if (!RB_EMPTY_ROOT(&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)) |
| mod_timer(&cfqd->idle_class_timer, end); |
| 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_exit_queue(elevator_t *e) |
| { |
| struct cfq_data *cfqd = e->elevator_data; |
| request_queue_t *q = cfqd->queue; |
| |
| cfq_shutdown_timer_wq(cfqd); |
| |
| spin_lock_irq(q->queue_lock); |
| |
| if (cfqd->active_queue) |
| __cfq_slice_expired(cfqd, cfqd->active_queue, 0); |
| |
| while (!list_empty(&cfqd->cic_list)) { |
| struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, |
| struct cfq_io_context, |
| queue_list); |
| |
| __cfq_exit_single_io_context(cfqd, cic); |
| } |
| |
| spin_unlock_irq(q->queue_lock); |
| |
| cfq_shutdown_timer_wq(cfqd); |
| |
| kfree(cfqd->cfq_hash); |
| kfree(cfqd); |
| } |
| |
| static void *cfq_init_queue(request_queue_t *q, elevator_t *e) |
| { |
| struct cfq_data *cfqd; |
| int i; |
| |
| cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node); |
| if (!cfqd) |
| return NULL; |
| |
| 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->cic_list); |
| |
| cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); |
| if (!cfqd->cfq_hash) |
| goto out_free; |
| |
| for (i = 0; i < CFQ_QHASH_ENTRIES; i++) |
| INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); |
| |
| cfqd->queue = q; |
| |
| 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); |
| |
| 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; |
| |
| return cfqd; |
| out_free: |
| kfree(cfqd); |
| return NULL; |
| } |
| |
| static void cfq_slab_kill(void) |
| { |
| 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) |
| { |
| 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 --> |
| */ |
| |
| 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(elevator_t *e, char *page) \ |
| { \ |
| struct cfq_data *cfqd = e->elevator_data; \ |
| 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_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_seek_max_show, cfqd->cfq_back_max, 0); |
| SHOW_FUNCTION(cfq_back_seek_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); |
| #undef SHOW_FUNCTION |
| |
| #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \ |
| static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ |
| { \ |
| struct cfq_data *cfqd = e->elevator_data; \ |
| 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_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_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); |
| STORE_FUNCTION(cfq_back_seek_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); |
| #undef STORE_FUNCTION |
| |
| #define CFQ_ATTR(name) \ |
| __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store) |
| |
| static struct elv_fs_entry cfq_attrs[] = { |
| CFQ_ATTR(quantum), |
| CFQ_ATTR(fifo_expire_sync), |
| CFQ_ATTR(fifo_expire_async), |
| CFQ_ATTR(back_seek_max), |
| CFQ_ATTR(back_seek_penalty), |
| CFQ_ATTR(slice_sync), |
| CFQ_ATTR(slice_async), |
| CFQ_ATTR(slice_async_rq), |
| CFQ_ATTR(slice_idle), |
| __ATTR_NULL |
| }; |
| |
| 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 = elv_rb_former_request, |
| .elevator_latter_req_fn = elv_rb_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, |
| .trim = cfq_free_io_context, |
| }, |
| .elevator_attrs = cfq_attrs, |
| .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) |
| { |
| DECLARE_COMPLETION(all_gone); |
| elv_unregister(&iosched_cfq); |
| ioc_gone = &all_gone; |
| /* ioc_gone's update must be visible before reading ioc_count */ |
| smp_wmb(); |
| if (elv_ioc_count_read(ioc_count)) |
| wait_for_completion(ioc_gone); |
| synchronize_rcu(); |
| 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"); |