diff options
Diffstat (limited to 'libdde-linux26/libdde_linux26/contrib/block/cfq-iosched.c')
| -rw-r--r-- | libdde-linux26/libdde_linux26/contrib/block/cfq-iosched.c | 2465 |
1 files changed, 0 insertions, 2465 deletions
diff --git a/libdde-linux26/libdde_linux26/contrib/block/cfq-iosched.c b/libdde-linux26/libdde_linux26/contrib/block/cfq-iosched.c deleted file mode 100644 index 37c1fca9..00000000 --- a/libdde-linux26/libdde_linux26/contrib/block/cfq-iosched.c +++ /dev/null @@ -1,2465 +0,0 @@ -/* - * 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@kernel.dk> - */ -#include <linux/module.h> -#include <linux/blkdev.h> -#include <linux/elevator.h> -#include <linux/rbtree.h> -#include <linux/ioprio.h> -#include <linux/blktrace_api.h> -#include <ddekit/timer.h> - -/* - * tunables - */ -/* max queue in one round of service */ -static const int cfq_quantum = 4; -static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; -/* maximum backwards seek, in KiB */ -static const int cfq_back_max = 16 * 1024; -/* penalty of a backwards seek */ -static const int cfq_back_penalty = 2; -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; - -/* - * offset from end of service tree - */ -#define CFQ_IDLE_DELAY (HZ / 5) - -/* - * below this threshold, we consider thinktime immediate - */ -#define CFQ_MIN_TT (2) - -#define CFQ_SLICE_SCALE (5) -#define CFQ_HW_QUEUE_MIN (5) - -#define RQ_CIC(rq) \ - ((struct cfq_io_context *) (rq)->elevator_private) -#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2) - -static struct kmem_cache *cfq_pool; -static struct kmem_cache *cfq_ioc_pool; - -static DEFINE_PER_CPU(unsigned long, ioc_count); -static struct completion *ioc_gone; -static DEFINE_SPINLOCK(ioc_gone_lock); - -#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 sample_valid(samples) ((samples) > 80) - -/* - * Most of our rbtree usage is for sorting with min extraction, so - * if we cache the leftmost node we don't have to walk down the tree - * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should - * move this into the elevator for the rq sorting as well. - */ -struct cfq_rb_root { - struct rb_root rb; - struct rb_node *left; -}; -#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, } - -/* - * Per block device queue structure - */ -struct cfq_data { - struct request_queue *queue; - - /* - * rr list of queues with requests and the count of them - */ - struct cfq_rb_root service_tree; - unsigned int busy_queues; - /* - * Used to track any pending rt requests so we can pre-empt current - * non-RT cfqq in service when this value is non-zero. - */ - unsigned int busy_rt_queues; - - int rq_in_driver; - int sync_flight; - - /* - * queue-depth detection - */ - int rq_queued; - int hw_tag; - int hw_tag_samples; - int rq_in_driver_peak; - - /* - * 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; - - /* - * async queue for each priority case - */ - struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR]; - struct cfq_queue *async_idle_cfqq; - - sector_t last_position; - 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; - /* various state flags, see below */ - unsigned int flags; - /* parent cfq_data */ - struct cfq_data *cfqd; - /* service_tree member */ - struct rb_node rb_node; - /* service_tree key */ - unsigned long rb_key; - /* 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]; - /* fifo list of requests in sort_list */ - struct list_head fifo; - - unsigned long slice_end; - long slice_resid; - - /* pending metadata requests */ - int meta_pending; - /* number of requests that are on the dispatch list or inside driver */ - int dispatched; - - /* io prio of this group */ - unsigned short ioprio, org_ioprio; - unsigned short ioprio_class, org_ioprio_class; - - pid_t pid; -}; - -enum cfqq_state_flags { - CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */ - CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */ - CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */ - CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */ - CFQ_CFQQ_FLAG_must_dispatch, /* must dispatch, even if expired */ - CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */ - CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */ - CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */ - CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */ - CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */ - CFQ_CFQQ_FLAG_sync, /* synchronous queue */ -}; - -#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); -CFQ_CFQQ_FNS(slice_new); -CFQ_CFQQ_FNS(sync); -#undef CFQ_CFQQ_FNS - -#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \ - blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args) -#define cfq_log(cfqd, fmt, args...) \ - blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) - -static void cfq_dispatch_insert(struct request_queue *, struct request *); -static struct cfq_queue *cfq_get_queue(struct cfq_data *, int, - struct io_context *, gfp_t); -static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, - struct io_context *); - -static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, - int is_sync) -{ - return cic->cfqq[!!is_sync]; -} - -static inline void cic_set_cfqq(struct cfq_io_context *cic, - struct cfq_queue *cfqq, int is_sync) -{ - cic->cfqq[!!is_sync] = cfqq; -} - -/* - * We regard a request as SYNC, if it's either a read or has the SYNC bit - * set (in which case it could also be direct WRITE). - */ -static inline int cfq_bio_sync(struct bio *bio) -{ - if (bio_data_dir(bio) == READ || bio_sync(bio)) - return 1; - - return 0; -} - -/* - * 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) { - cfq_log(cfqd, "schedule dispatch"); - kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work); - } -} - -static int cfq_queue_empty(struct request_queue *q) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - return !cfqd->busy_queues; -} - -/* - * 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_slice(struct cfq_data *cfqd, int sync, - unsigned short prio) -{ - const int base_slice = cfqd->cfq_slice[sync]; - - WARN_ON(prio >= IOPRIO_BE_NR); - - return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio)); -} - -static inline int -cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), 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; - cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies); -} - -/* - * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end - * isn't valid until the first request from the dispatch is activated - * and the slice time set. - */ -static inline int cfq_slice_used(struct cfq_queue *cfqq) -{ - if (cfq_cfqq_slice_new(cfqq)) - return 0; - if (time_before(jiffies, cfqq->slice_end)) - return 0; - - return 1; -} - -/* - * 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_position; - - /* - * 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; - } -} - -/* - * The below is leftmost cache rbtree addon - */ -static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) -{ - if (!root->left) - root->left = rb_first(&root->rb); - - if (root->left) - return rb_entry(root->left, struct cfq_queue, rb_node); - - return NULL; -} - -static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root) -{ - if (root->left == n) - root->left = NULL; - - rb_erase(n, &root->rb); - RB_CLEAR_NODE(n); -} - -/* - * 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 unsigned long cfq_slice_offset(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - /* - * just an approximation, should be ok. - */ - return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) - - cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio)); -} - -/* - * The cfqd->service_tree holds all pending cfq_queue's that have - * requests waiting to be processed. It is sorted in the order that - * we will service the queues. - */ -static void cfq_service_tree_add(struct cfq_data *cfqd, - struct cfq_queue *cfqq, int add_front) -{ - struct rb_node **p, *parent; - struct cfq_queue *__cfqq; - unsigned long rb_key; - int left; - - if (cfq_class_idle(cfqq)) { - rb_key = CFQ_IDLE_DELAY; - parent = rb_last(&cfqd->service_tree.rb); - if (parent && parent != &cfqq->rb_node) { - __cfqq = rb_entry(parent, struct cfq_queue, rb_node); - rb_key += __cfqq->rb_key; - } else - rb_key += jiffies; - } else if (!add_front) { - rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; - rb_key += cfqq->slice_resid; - cfqq->slice_resid = 0; - } else - rb_key = 0; - - if (!RB_EMPTY_NODE(&cfqq->rb_node)) { - /* - * same position, nothing more to do - */ - if (rb_key == cfqq->rb_key) - return; - - cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); - } - - left = 1; - parent = NULL; - p = &cfqd->service_tree.rb.rb_node; - while (*p) { - struct rb_node **n; - - parent = *p; - __cfqq = rb_entry(parent, struct cfq_queue, rb_node); - - /* - * sort RT queues first, we always want to give - * preference to them. IDLE queues goes to the back. - * after that, sort on the next service time. - */ - if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq)) - n = &(*p)->rb_left; - else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq)) - n = &(*p)->rb_right; - else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq)) - n = &(*p)->rb_left; - else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq)) - n = &(*p)->rb_right; - else if (rb_key < __cfqq->rb_key) - n = &(*p)->rb_left; - else - n = &(*p)->rb_right; - - if (n == &(*p)->rb_right) - left = 0; - - p = n; - } - - if (left) - cfqd->service_tree.left = &cfqq->rb_node; - - cfqq->rb_key = rb_key; - rb_link_node(&cfqq->rb_node, parent, p); - rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb); -} - -/* - * Update cfqq's position in the service tree. - */ -static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - /* - * Resorting requires the cfqq to be on the RR list already. - */ - if (cfq_cfqq_on_rr(cfqq)) - cfq_service_tree_add(cfqd, cfqq, 0); -} - -/* - * add to busy list of queues for service, trying to be fair in ordering - * the pending list according to last request service - */ -static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfq_log_cfqq(cfqd, cfqq, "add_to_rr"); - BUG_ON(cfq_cfqq_on_rr(cfqq)); - cfq_mark_cfqq_on_rr(cfqq); - cfqd->busy_queues++; - if (cfq_class_rt(cfqq)) - cfqd->busy_rt_queues++; - - cfq_resort_rr_list(cfqd, cfqq); -} - -/* - * Called when the cfqq no longer has requests pending, remove it from - * the service tree. - */ -static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - cfq_log_cfqq(cfqd, cfqq, "del_from_rr"); - BUG_ON(!cfq_cfqq_on_rr(cfqq)); - cfq_clear_cfqq_on_rr(cfqq); - - if (!RB_EMPTY_NODE(&cfqq->rb_node)) - cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); - - BUG_ON(!cfqd->busy_queues); - cfqd->busy_queues--; - if (cfq_class_rt(cfqq)) - cfqd->busy_rt_queues--; -} - -/* - * rb tree support functions - */ -static 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); - - if (!cfq_cfqq_on_rr(cfqq)) - cfq_add_cfqq_rr(cfqd, cfqq); - - /* - * 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); -} - -static 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; - struct cfq_io_context *cic; - struct cfq_queue *cfqq; - - cic = cfq_cic_lookup(cfqd, tsk->io_context); - if (!cic) - return NULL; - - cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); - 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(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - cfqd->rq_in_driver++; - cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d", - cfqd->rq_in_driver); - - cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors; -} - -static void cfq_deactivate_request(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; - cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d", - 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); - - cfqq->cfqd->rq_queued--; - if (rq_is_meta(rq)) { - WARN_ON(!cfqq->meta_pending); - cfqq->meta_pending--; - } -} - -static int cfq_merge(struct request_queue *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(struct request_queue *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(struct request_queue *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 int cfq_allow_merge(struct request_queue *q, struct request *rq, - struct bio *bio) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_io_context *cic; - struct cfq_queue *cfqq; - - /* - * Disallow merge of a sync bio into an async request. - */ - if (cfq_bio_sync(bio) && !rq_is_sync(rq)) - return 0; - - /* - * Lookup the cfqq that this bio will be queued with. Allow - * merge only if rq is queued there. - */ - cic = cfq_cic_lookup(cfqd, current->io_context); - if (!cic) - return 0; - - cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); - if (cfqq == RQ_CFQQ(rq)) - return 1; - - return 0; -} - -static void __cfq_set_active_queue(struct cfq_data *cfqd, - struct cfq_queue *cfqq) -{ - if (cfqq) { - cfq_log_cfqq(cfqd, cfqq, "set_active"); - cfqq->slice_end = 0; - cfq_clear_cfqq_must_alloc_slice(cfqq); - cfq_clear_cfqq_fifo_expire(cfqq); - cfq_mark_cfqq_slice_new(cfqq); - cfq_clear_cfqq_queue_new(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 timed_out) -{ - cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); - - if (cfq_cfqq_wait_request(cfqq)) - del_timer(&cfqd->idle_slice_timer); - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - - /* - * store what was left of this slice, if the queue idled/timed out - */ - if (timed_out && !cfq_cfqq_slice_new(cfqq)) { - cfqq->slice_resid = cfqq->slice_end - jiffies; - cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid); - } - - cfq_resort_rr_list(cfqd, cfqq); - - if (cfqq == cfqd->active_queue) - cfqd->active_queue = NULL; - - if (cfqd->active_cic) { - put_io_context(cfqd->active_cic->ioc); - cfqd->active_cic = NULL; - } -} - -static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - - if (cfqq) - __cfq_slice_expired(cfqd, cfqq, timed_out); -} - -/* - * Get next queue for service. Unless we have a queue preemption, - * we'll simply select the first cfqq in the service tree. - */ -static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) -{ - if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) - return NULL; - - return cfq_rb_first(&cfqd->service_tree); -} - -/* - * Get and set a new active queue for service. - */ -static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - - cfqq = cfq_get_next_queue(cfqd); - __cfq_set_active_queue(cfqd, cfqq); - return cfqq; -} - -static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, - struct request *rq) -{ - if (rq->sector >= cfqd->last_position) - return rq->sector - cfqd->last_position; - else - return cfqd->last_position - rq->sector; -} - -static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq) -{ - struct cfq_io_context *cic = cfqd->active_cic; - - if (!sample_valid(cic->seek_samples)) - return 0; - - return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean; -} - -static int cfq_close_cooperator(struct cfq_data *cfq_data, - struct cfq_queue *cfqq) -{ - /* - * We should notice if some of the queues are cooperating, eg - * working closely on the same area of the disk. In that case, - * we can group them together and don't waste time idling. - */ - return 0; -} - -#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024)) - -static void cfq_arm_slice_timer(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq = cfqd->active_queue; - struct cfq_io_context *cic; - unsigned long sl; - - /* - * SSD device without seek penalty, disable idling. But only do so - * for devices that support queuing, otherwise we still have a problem - * with sync vs async workloads. - */ - if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag) - return; - - WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list)); - WARN_ON(cfq_cfqq_slice_new(cfqq)); - - /* - * idle is disabled, either manually or by past process history - */ - if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq)) - return; - - /* - * still requests with the driver, don't idle - */ - if (cfqd->rq_in_driver) - return; - - /* - * task has exited, don't wait - */ - cic = cfqd->active_cic; - if (!cic || !atomic_read(&cic->ioc->nr_tasks)) - return; - - /* - * See if this prio level has a good candidate - */ - if (cfq_close_cooperator(cfqd, cfqq) && - (sample_valid(cic->ttime_samples) && cic->ttime_mean > 2)) - return; - - cfq_mark_cfqq_must_dispatch(cfqq); - cfq_mark_cfqq_wait_request(cfqq); - - /* - * 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 - */ - sl = cfqd->cfq_slice_idle; - if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic)) - sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT)); - - mod_timer(&cfqd->idle_slice_timer, jiffies + sl); - cfq_log(cfqd, "arm_idle: %lu", sl); -} - -/* - * Move request from internal lists to the request queue dispatch list. - */ -static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - cfq_log_cfqq(cfqd, cfqq, "dispatch_insert"); - - cfq_remove_request(rq); - cfqq->dispatched++; - elv_dispatch_sort(q, rq); - - if (cfq_cfqq_sync(cfqq)) - cfqd->sync_flight++; -} - -/* - * return expired entry, or NULL to just start from scratch in rbtree - */ -static 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; - - cfq_mark_cfqq_fifo_expire(cfqq); - - if (list_empty(&cfqq->fifo)) - return NULL; - - fifo = cfq_cfqq_sync(cfqq); - rq = rq_entry_fifo(cfqq->fifo.next); - - if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) - rq = NULL; - - cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq); - return rq; -} - -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)); -} - -/* - * Select a queue for service. If we have a current active queue, - * check whether to continue servicing it, or retrieve and set a new one. - */ -static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - - cfqq = cfqd->active_queue; - if (!cfqq) - goto new_queue; - - /* - * The active queue has run out of time, expire it and select new. - */ - if (cfq_slice_used(cfqq)) - goto expire; - - /* - * If we have a RT cfqq waiting, then we pre-empt the current non-rt - * cfqq. - */ - if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) { - /* - * We simulate this as cfqq timed out so that it gets to bank - * the remaining of its time slice. - */ - cfq_log_cfqq(cfqd, cfqq, "preempt"); - cfq_slice_expired(cfqd, 1); - goto new_queue; - } - - /* - * The active queue has requests and isn't expired, allow it to - * dispatch. - */ - if (!RB_EMPTY_ROOT(&cfqq->sort_list)) - goto keep_queue; - - /* - * No requests pending. If the active queue still has requests in - * flight or is idling for a new request, allow either of these - * conditions to happen (or time out) before selecting a new queue. - */ - if (timer_pending(&cfqd->idle_slice_timer) || - (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) { - cfqq = NULL; - goto keep_queue; - } - -expire: - cfq_slice_expired(cfqd, 0); -new_queue: - cfqq = cfq_set_active_queue(cfqd); -keep_queue: - return cfqq; -} - -/* - * Dispatch some requests from cfqq, moving them to the request queue - * dispatch list. - */ -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 - */ - rq = cfq_check_fifo(cfqq); - if (rq == NULL) - rq = cfqq->next_rq; - - /* - * finally, insert request into driver dispatch list - */ - cfq_dispatch_insert(cfqd->queue, rq); - - 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; - - /* - * If there is a non-empty RT cfqq waiting for current - * cfqq's timeslice to complete, pre-empt this cfqq - */ - if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) - break; - - } while (dispatched < max_dispatch); - - /* - * expire an async queue immediately if it has used up its slice. idle - * queue always expire after 1 dispatch round. - */ - if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) && - dispatched >= cfq_prio_to_maxrq(cfqd, cfqq)) || - cfq_class_idle(cfqq))) { - cfqq->slice_end = jiffies + 1; - cfq_slice_expired(cfqd, 0); - } - - return dispatched; -} - -static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) -{ - int dispatched = 0; - - while (cfqq->next_rq) { - cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); - dispatched++; - } - - BUG_ON(!list_empty(&cfqq->fifo)); - return dispatched; -} - -/* - * Drain our current requests. Used for barriers and when switching - * io schedulers on-the-fly. - */ -static int cfq_forced_dispatch(struct cfq_data *cfqd) -{ - struct cfq_queue *cfqq; - int dispatched = 0; - - while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL) - dispatched += __cfq_forced_dispatch_cfqq(cfqq); - - cfq_slice_expired(cfqd, 0); - - BUG_ON(cfqd->busy_queues); - - cfq_log(cfqd, "forced_dispatch=%d\n", dispatched); - return dispatched; -} - -static int cfq_dispatch_requests(struct request_queue *q, int force) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq; - int dispatched; - - if (!cfqd->busy_queues) - return 0; - - if (unlikely(force)) - return cfq_forced_dispatch(cfqd); - - dispatched = 0; - while ((cfqq = cfq_select_queue(cfqd)) != NULL) { - int max_dispatch; - - max_dispatch = cfqd->cfq_quantum; - if (cfq_class_idle(cfqq)) - max_dispatch = 1; - - if (cfqq->dispatched >= max_dispatch && cfqd->busy_queues > 1) - break; - - if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) - break; - - cfq_clear_cfqq_must_dispatch(cfqq); - cfq_clear_cfqq_wait_request(cfqq); - del_timer(&cfqd->idle_slice_timer); - - dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); - } - - cfq_log(cfqd, "dispatched=%d", dispatched); - 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; - - cfq_log_cfqq(cfqd, cfqq, "put_queue"); - BUG_ON(rb_first(&cfqq->sort_list)); - BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]); - BUG_ON(cfq_cfqq_on_rr(cfqq)); - - if (unlikely(cfqd->active_queue == cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - - kmem_cache_free(cfq_pool, cfqq); -} - -/* - * Must always be called with the rcu_read_lock() held - */ -static void -__call_for_each_cic(struct io_context *ioc, - void (*func)(struct io_context *, struct cfq_io_context *)) -{ - struct cfq_io_context *cic; - struct hlist_node *n; - - hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list) - func(ioc, cic); -} - -/* - * Call func for each cic attached to this ioc. - */ -static void -call_for_each_cic(struct io_context *ioc, - void (*func)(struct io_context *, struct cfq_io_context *)) -{ - rcu_read_lock(); - __call_for_each_cic(ioc, func); - rcu_read_unlock(); -} - -static void cfq_cic_free_rcu(struct rcu_head *head) -{ - struct cfq_io_context *cic; - - cic = container_of(head, struct cfq_io_context, rcu_head); - - kmem_cache_free(cfq_ioc_pool, cic); - elv_ioc_count_dec(ioc_count); - - if (ioc_gone) { - /* - * CFQ scheduler is exiting, grab exit lock and check - * the pending io context count. If it hits zero, - * complete ioc_gone and set it back to NULL - */ - spin_lock(&ioc_gone_lock); - if (ioc_gone && !elv_ioc_count_read(ioc_count)) { - complete(ioc_gone); - ioc_gone = NULL; - } - spin_unlock(&ioc_gone_lock); - } -} - -static void cfq_cic_free(struct cfq_io_context *cic) -{ - call_rcu(&cic->rcu_head, cfq_cic_free_rcu); -} - -static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic) -{ - unsigned long flags; - - BUG_ON(!cic->dead_key); - - spin_lock_irqsave(&ioc->lock, flags); - radix_tree_delete(&ioc->radix_root, cic->dead_key); - hlist_del_rcu(&cic->cic_list); - spin_unlock_irqrestore(&ioc->lock, flags); - - cfq_cic_free(cic); -} - -/* - * Must be called with rcu_read_lock() held or preemption otherwise disabled. - * Only two callers of this - ->dtor() which is called with the rcu_read_lock(), - * and ->trim() which is called with the task lock held - */ -static void cfq_free_io_context(struct io_context *ioc) -{ - /* - * ioc->refcount is zero here, or we are called from elv_unregister(), - * so no more cic's are allowed to be linked into this ioc. So it - * should be ok to iterate over the known list, we will see all cic's - * since no new ones are added. - */ - __call_for_each_cic(ioc, cic_free_func); -} - -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_schedule_dispatch(cfqd); - } - - cfq_put_queue(cfqq); -} - -static void __cfq_exit_single_io_context(struct cfq_data *cfqd, - struct cfq_io_context *cic) -{ - struct io_context *ioc = cic->ioc; - - list_del_init(&cic->queue_list); - - /* - * Make sure key == NULL is seen for dead queues - */ - smp_wmb(); - cic->dead_key = (unsigned long) cic->key; - cic->key = NULL; - - if (ioc->ioc_data == cic) - rcu_assign_pointer(ioc->ioc_data, 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; - } -} - -static void cfq_exit_single_io_context(struct io_context *ioc, - struct cfq_io_context *cic) -{ - struct cfq_data *cfqd = cic->key; - - if (cfqd) { - struct request_queue *q = cfqd->queue; - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - - /* - * Ensure we get a fresh copy of the ->key to prevent - * race between exiting task and queue - */ - smp_read_barrier_depends(); - if (cic->key) - __cfq_exit_single_io_context(cfqd, cic); - - spin_unlock_irqrestore(q->queue_lock, flags); - } -} - -/* - * The process that ioc belongs to has exited, we need to clean up - * and put the internal structures we have that belongs to that process. - */ -static void cfq_exit_io_context(struct io_context *ioc) -{ - call_for_each_cic(ioc, cfq_exit_single_io_context); -} - -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 | __GFP_ZERO, - cfqd->queue->node); - if (cic) { - cic->last_end_request = jiffies; - INIT_LIST_HEAD(&cic->queue_list); - INIT_HLIST_NODE(&cic->cic_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 io_context *ioc) -{ - struct task_struct *tsk = current; - int ioprio_class; - - if (!cfq_cfqq_prio_changed(cfqq)) - return; - - ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio); - switch (ioprio_class) { - default: - printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); - case IOPRIO_CLASS_NONE: - /* - * no prio set, inherit CPU scheduling settings - */ - cfqq->ioprio = task_nice_ioprio(tsk); - cfqq->ioprio_class = task_nice_ioclass(tsk); - break; - case IOPRIO_CLASS_RT: - cfqq->ioprio = task_ioprio(ioc); - cfqq->ioprio_class = IOPRIO_CLASS_RT; - break; - case IOPRIO_CLASS_BE: - cfqq->ioprio = task_ioprio(ioc); - 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; - cfq_clear_cfqq_prio_changed(cfqq); -} - -static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic) -{ - struct cfq_data *cfqd = cic->key; - struct cfq_queue *cfqq; - unsigned long flags; - - if (unlikely(!cfqd)) - return; - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - cfqq = cic->cfqq[ASYNC]; - if (cfqq) { - struct cfq_queue *new_cfqq; - new_cfqq = cfq_get_queue(cfqd, ASYNC, cic->ioc, 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_irqrestore(cfqd->queue->queue_lock, flags); -} - -static void cfq_ioc_set_ioprio(struct io_context *ioc) -{ - call_for_each_cic(ioc, changed_ioprio); - ioc->ioprio_changed = 0; -} - -static struct cfq_queue * -cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync, - struct io_context *ioc, gfp_t gfp_mask) -{ - struct cfq_queue *cfqq, *new_cfqq = NULL; - struct cfq_io_context *cic; - -retry: - cic = cfq_cic_lookup(cfqd, ioc); - /* cic always exists here */ - cfqq = cic_to_cfqq(cic, is_sync); - - 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 | __GFP_ZERO, - cfqd->queue->node); - spin_lock_irq(cfqd->queue->queue_lock); - goto retry; - } else { - cfqq = kmem_cache_alloc_node(cfq_pool, - gfp_mask | __GFP_ZERO, - cfqd->queue->node); - if (!cfqq) - goto out; - } - - RB_CLEAR_NODE(&cfqq->rb_node); - INIT_LIST_HEAD(&cfqq->fifo); - - atomic_set(&cfqq->ref, 0); - cfqq->cfqd = cfqd; - - cfq_mark_cfqq_prio_changed(cfqq); - cfq_mark_cfqq_queue_new(cfqq); - - cfq_init_prio_data(cfqq, ioc); - - if (is_sync) { - if (!cfq_class_idle(cfqq)) - cfq_mark_cfqq_idle_window(cfqq); - cfq_mark_cfqq_sync(cfqq); - } - cfqq->pid = current->pid; - cfq_log_cfqq(cfqd, cfqq, "alloced"); - } - - if (new_cfqq) - kmem_cache_free(cfq_pool, new_cfqq); - -out: - WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq); - return cfqq; -} - -static struct cfq_queue ** -cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio) -{ - switch (ioprio_class) { - case IOPRIO_CLASS_RT: - return &cfqd->async_cfqq[0][ioprio]; - case IOPRIO_CLASS_BE: - return &cfqd->async_cfqq[1][ioprio]; - case IOPRIO_CLASS_IDLE: - return &cfqd->async_idle_cfqq; - default: - BUG(); - } -} - -static struct cfq_queue * -cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc, - gfp_t gfp_mask) -{ - const int ioprio = task_ioprio(ioc); - const int ioprio_class = task_ioprio_class(ioc); - struct cfq_queue **async_cfqq = NULL; - struct cfq_queue *cfqq = NULL; - - if (!is_sync) { - async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); - cfqq = *async_cfqq; - } - - if (!cfqq) { - cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask); - if (!cfqq) - return NULL; - } - - /* - * pin the queue now that it's allocated, scheduler exit will prune it - */ - if (!is_sync && !(*async_cfqq)) { - atomic_inc(&cfqq->ref); - *async_cfqq = cfqq; - } - - atomic_inc(&cfqq->ref); - return cfqq; -} - -/* - * We drop cfq io contexts lazily, so we may find a dead one. - */ -static void -cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc, - struct cfq_io_context *cic) -{ - unsigned long flags; - - WARN_ON(!list_empty(&cic->queue_list)); - - spin_lock_irqsave(&ioc->lock, flags); - - BUG_ON(ioc->ioc_data == cic); - - radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd); - hlist_del_rcu(&cic->cic_list); - spin_unlock_irqrestore(&ioc->lock, flags); - - cfq_cic_free(cic); -} - -static struct cfq_io_context * -cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc) -{ - struct cfq_io_context *cic; - unsigned long flags; - void *k; - - if (unlikely(!ioc)) - return NULL; - - rcu_read_lock(); - - /* - * we maintain a last-hit cache, to avoid browsing over the tree - */ - cic = rcu_dereference(ioc->ioc_data); - if (cic && cic->key == cfqd) { - rcu_read_unlock(); - return cic; - } - - do { - cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd); - rcu_read_unlock(); - if (!cic) - break; - /* ->key must be copied to avoid race with cfq_exit_queue() */ - k = cic->key; - if (unlikely(!k)) { - cfq_drop_dead_cic(cfqd, ioc, cic); - rcu_read_lock(); - continue; - } - - spin_lock_irqsave(&ioc->lock, flags); - rcu_assign_pointer(ioc->ioc_data, cic); - spin_unlock_irqrestore(&ioc->lock, flags); - break; - } while (1); - - return cic; -} - -/* - * Add cic into ioc, using cfqd as the search key. This enables us to lookup - * the process specific cfq io context when entered from the block layer. - * Also adds the cic to a per-cfqd list, used when this queue is removed. - */ -static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, - struct cfq_io_context *cic, gfp_t gfp_mask) -{ - unsigned long flags; - int ret; - - ret = radix_tree_preload(gfp_mask); - if (!ret) { - cic->ioc = ioc; - cic->key = cfqd; - - spin_lock_irqsave(&ioc->lock, flags); - ret = radix_tree_insert(&ioc->radix_root, - (unsigned long) cfqd, cic); - if (!ret) - hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list); - spin_unlock_irqrestore(&ioc->lock, flags); - - radix_tree_preload_end(); - - if (!ret) { - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - list_add(&cic->queue_list, &cfqd->cic_list); - spin_unlock_irqrestore(cfqd->queue->queue_lock, flags); - } - } - - if (ret) - printk(KERN_ERR "cfq: cic link failed!\n"); - - return ret; -} - -/* - * 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_lookup(cfqd, ioc); - if (cic) - goto out; - - cic = cfq_alloc_io_context(cfqd, gfp_mask); - if (cic == NULL) - goto err; - - if (cfq_cic_link(cfqd, ioc, cic, gfp_mask)) - goto err_free; - -out: - smp_read_barrier_depends(); - if (unlikely(ioc->ioprio_changed)) - cfq_ioc_set_ioprio(ioc); - - return cic; -err_free: - cfq_cic_free(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 = jiffies - cic->last_end_request; - unsigned long 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 old_idle, enable_idle; - - /* - * Don't idle for async or idle io prio class - */ - if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq)) - return; - - enable_idle = old_idle = cfq_cfqq_idle_window(cfqq); - - if (!atomic_read(&cic->ioc->nr_tasks) || !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 (old_idle != enable_idle) { - cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle); - 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; - - cfqq = cfqd->active_queue; - if (!cfqq) - return 0; - - if (cfq_slice_used(cfqq)) - return 1; - - if (cfq_class_idle(new_cfqq)) - return 0; - - if (cfq_class_idle(cfqq)) - return 1; - - /* - * 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; - - /* - * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice. - */ - if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq)) - return 1; - - if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq)) - return 0; - - /* - * if this request is as-good as one we would expect from the - * current cfqq, let it preempt - */ - if (cfq_rq_close(cfqd, rq)) - 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_log_cfqq(cfqd, cfqq, "preempt"); - cfq_slice_expired(cfqd, 1); - - /* - * 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)); - - cfq_service_tree_add(cfqd, cfqq, 1); - - cfqq->slice_end = 0; - cfq_mark_cfqq_slice_new(cfqq); -} - -/* - * 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); - - cfqd->rq_queued++; - if (rq_is_meta(rq)) - cfqq->meta_pending++; - - cfq_update_io_thinktime(cfqd, cic); - cfq_update_io_seektime(cfqd, cic, rq); - cfq_update_idle_window(cfqd, cfqq, cic); - - 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 or - * this new queue is RT and the current one is BE - */ - cfq_preempt_queue(cfqd, cfqq); - cfq_mark_cfqq_must_dispatch(cfqq); - blk_start_queueing(cfqd->queue); - } -} - -static void cfq_insert_request(struct request_queue *q, struct request *rq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = RQ_CFQQ(rq); - - cfq_log_cfqq(cfqd, cfqq, "insert_request"); - cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc); - - cfq_add_rq_rb(rq); - - list_add_tail(&rq->queuelist, &cfqq->fifo); - - cfq_rq_enqueued(cfqd, cfqq, rq); -} - -/* - * Update hw_tag based on peak queue depth over 50 samples under - * sufficient load. - */ -static void cfq_update_hw_tag(struct cfq_data *cfqd) -{ - if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak) - cfqd->rq_in_driver_peak = cfqd->rq_in_driver; - - if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN && - cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN) - return; - - if (cfqd->hw_tag_samples++ < 50) - return; - - if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN) - cfqd->hw_tag = 1; - else - cfqd->hw_tag = 0; - - cfqd->hw_tag_samples = 0; - cfqd->rq_in_driver_peak = 0; -} - -static void cfq_completed_request(struct request_queue *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; - cfq_log_cfqq(cfqd, cfqq, "complete"); - - cfq_update_hw_tag(cfqd); - - WARN_ON(!cfqd->rq_in_driver); - WARN_ON(!cfqq->dispatched); - cfqd->rq_in_driver--; - cfqq->dispatched--; - - if (cfq_cfqq_sync(cfqq)) - cfqd->sync_flight--; - - if (!cfq_class_idle(cfqq)) - cfqd->last_end_request = now; - - 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 (cfq_cfqq_slice_new(cfqq)) { - cfq_set_prio_slice(cfqd, cfqq); - cfq_clear_cfqq_slice_new(cfqq); - } - if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq)) - cfq_slice_expired(cfqd, 1); - else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) - cfq_arm_slice_timer(cfqd); - } - - if (!cfqd->rq_in_driver) - 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) -{ - 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; - } -} - -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(struct request_queue *q, int rw) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct task_struct *tsk = current; - struct cfq_io_context *cic; - 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 - */ - cic = cfq_cic_lookup(cfqd, tsk->io_context); - if (!cic) - return ELV_MQUEUE_MAY; - - cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC); - if (cfqq) { - cfq_init_prio_data(cfqq, cic->ioc); - cfq_prio_boost(cfqq); - - return __cfq_may_queue(cfqq); - } - - return ELV_MQUEUE_MAY; -} - -/* - * queue lock held here - */ -static void cfq_put_request(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(struct request_queue *q, struct request *rq, gfp_t gfp_mask) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_io_context *cic; - const int rw = rq_data_dir(rq); - const int is_sync = rq_is_sync(rq); - struct cfq_queue *cfqq; - unsigned long flags; - - 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; - - cfqq = cic_to_cfqq(cic, is_sync); - if (!cfqq) { - cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask); - - if (!cfqq) - goto queue_fail; - - cic_set_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); - cfq_log(cfqd, "set_request fail"); - return 1; -} - -static void cfq_kick_queue(struct work_struct *work) -{ - struct cfq_data *cfqd = - container_of(work, struct cfq_data, unplug_work); - struct request_queue *q = cfqd->queue; - 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; - int timed_out = 1; - - cfq_log(cfqd, "idle timer fired"); - - spin_lock_irqsave(cfqd->queue->queue_lock, flags); - - cfqq = cfqd->active_queue; - if (cfqq) { - timed_out = 0; - - /* - * expired - */ - if (cfq_slice_used(cfqq)) - 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, timed_out); -out_kick: - cfq_schedule_dispatch(cfqd); -out_cont: - 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); - cancel_work_sync(&cfqd->unplug_work); -} - -static void cfq_put_async_queues(struct cfq_data *cfqd) -{ - int i; - - for (i = 0; i < IOPRIO_BE_NR; i++) { - if (cfqd->async_cfqq[0][i]) - cfq_put_queue(cfqd->async_cfqq[0][i]); - if (cfqd->async_cfqq[1][i]) - cfq_put_queue(cfqd->async_cfqq[1][i]); - } - - if (cfqd->async_idle_cfqq) - cfq_put_queue(cfqd->async_idle_cfqq); -} - -static void cfq_exit_queue(struct elevator_queue *e) -{ - struct cfq_data *cfqd = e->elevator_data; - struct request_queue *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); - } - - cfq_put_async_queues(cfqd); - - spin_unlock_irq(q->queue_lock); - - cfq_shutdown_timer_wq(cfqd); - - kfree(cfqd); -} - -static void *cfq_init_queue(struct request_queue *q) -{ - struct cfq_data *cfqd; - - cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node); - if (!cfqd) - return NULL; - - cfqd->service_tree = CFQ_RB_ROOT; - INIT_LIST_HEAD(&cfqd->cic_list); - - 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_WORK(&cfqd->unplug_work, cfq_kick_queue); - - cfqd->last_end_request = jiffies; - cfqd->cfq_quantum = cfq_quantum; - cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; - cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; - cfqd->cfq_back_max = cfq_back_max; - cfqd->cfq_back_penalty = cfq_back_penalty; - cfqd->cfq_slice[0] = cfq_slice_async; - cfqd->cfq_slice[1] = cfq_slice_sync; - cfqd->cfq_slice_async_rq = cfq_slice_async_rq; - cfqd->cfq_slice_idle = cfq_slice_idle; - cfqd->hw_tag = 1; - - return cfqd; -} - -static void cfq_slab_kill(void) -{ - /* - * Caller already ensured that pending RCU callbacks are completed, - * so we should have no busy allocations at this point. - */ - 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(cfq_queue, 0); - if (!cfq_pool) - goto fail; - - cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0); - 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(struct elevator_queue *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(struct elevator_queue *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_allow_merge_fn = cfq_allow_merge, - .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) -{ - /* - * 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; - - elv_register(&iosched_cfq); - - return 0; -} - -static void __exit cfq_exit(void) -{ - DECLARE_COMPLETION_ONSTACK(all_gone); - elv_unregister(&iosched_cfq); - ioc_gone = &all_gone; - /* ioc_gone's update must be visible before reading ioc_count */ - smp_wmb(); - - /* - * this also protects us from entering cfq_slab_kill() with - * pending RCU callbacks - */ - if (elv_ioc_count_read(ioc_count)) - wait_for_completion(&all_gone); - 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"); |