From 9817064b68fef7e4580c6df1ea597e106b9ff88b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 28 Jul 2006 09:23:08 +0200 Subject: [PATCH] elevator: move the backmerging logic into the elevator core Right now, every IO scheduler implements its own backmerging (except for noop, which does no merging). That results in duplicated code for essentially the same operation, which is never a good thing. This patch moves the backmerging out of the io schedulers and into the elevator core. We save 1.6kb of text and as a bonus get backmerging for noop as well. Win-win! Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 86 ++--------------------------------------------------- 1 file changed, 3 insertions(+), 83 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 3a3aee08ec5..1b803c0c90f 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -41,16 +41,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock); #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) -/* - * for the hash of crq inside the cfqq - */ -#define CFQ_MHASH_SHIFT 6 -#define CFQ_MHASH_BLOCK(sec) ((sec) >> 3) -#define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT) -#define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT) -#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors) -#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash) - #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) #define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) @@ -112,11 +102,6 @@ struct cfq_data { */ struct hlist_head *cfq_hash; - /* - * global crq hash for all queues - */ - struct hlist_head *crq_hash; - mempool_t *crq_pool; int rq_in_driver; @@ -203,7 +188,6 @@ struct cfq_rq { struct rb_node rb_node; sector_t rb_key; struct request *request; - struct hlist_node hash; struct cfq_queue *cfq_queue; struct cfq_io_context *io_context; @@ -271,42 +255,6 @@ static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsi static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); -/* - * lots of deadline iosched dupes, can be abstracted later... - */ -static inline void cfq_del_crq_hash(struct cfq_rq *crq) -{ - hlist_del_init(&crq->hash); -} - -static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq) -{ - const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request)); - - hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]); -} - -static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) -{ - struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)]; - struct hlist_node *entry, *next; - - hlist_for_each_safe(entry, next, hash_list) { - struct cfq_rq *crq = list_entry_hash(entry); - struct request *__rq = crq->request; - - if (!rq_mergeable(__rq)) { - cfq_del_crq_hash(crq); - continue; - } - - if (rq_hash_key(__rq) == offset) - return __rq; - } - - return NULL; -} - /* * scheduler run of queue, if there are requests pending and no one in the * driver that will restart queueing @@ -677,7 +625,6 @@ static void cfq_remove_request(struct request *rq) list_del_init(&rq->queuelist); cfq_del_crq_rb(crq); - cfq_del_crq_hash(crq); } static int @@ -685,34 +632,20 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) { struct cfq_data *cfqd = q->elevator->elevator_data; struct request *__rq; - int ret; - - __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); - if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_BACK_MERGE; - goto out; - } __rq = cfq_find_rq_fmerge(cfqd, bio); if (__rq && elv_rq_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; + *req = __rq; + return ELEVATOR_FRONT_MERGE; } return ELEVATOR_NO_MERGE; -out: - *req = __rq; - return ret; } static void cfq_merged_request(request_queue_t *q, struct request *req) { - struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_rq *crq = RQ_DATA(req); - cfq_del_crq_hash(crq); - cfq_add_crq_hash(cfqd, crq); - if (rq_rb_key(req) != crq->rb_key) { struct cfq_queue *cfqq = crq->cfq_queue; @@ -1825,9 +1758,6 @@ static void cfq_insert_request(request_queue_t *q, struct request *rq) list_add_tail(&rq->queuelist, &cfqq->fifo); - if (rq_mergeable(rq)) - cfq_add_crq_hash(cfqd, crq); - cfq_crq_enqueued(cfqd, cfqq, crq); } @@ -2055,7 +1985,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, RB_CLEAR_NODE(&crq->rb_node); crq->rb_key = 0; crq->request = rq; - INIT_HLIST_NODE(&crq->hash); crq->cfq_queue = cfqq; crq->io_context = cic; @@ -2221,7 +2150,6 @@ static void cfq_exit_queue(elevator_t *e) cfq_shutdown_timer_wq(cfqd); mempool_destroy(cfqd->crq_pool); - kfree(cfqd->crq_hash); kfree(cfqd->cfq_hash); kfree(cfqd); } @@ -2246,20 +2174,14 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) INIT_LIST_HEAD(&cfqd->empty_list); INIT_LIST_HEAD(&cfqd->cic_list); - cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL); - if (!cfqd->crq_hash) - goto out_crqhash; - cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); if (!cfqd->cfq_hash) - goto out_cfqhash; + goto out_crqhash; cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool); if (!cfqd->crq_pool) goto out_crqpool; - for (i = 0; i < CFQ_MHASH_ENTRIES; i++) - INIT_HLIST_HEAD(&cfqd->crq_hash[i]); for (i = 0; i < CFQ_QHASH_ENTRIES; i++) INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); @@ -2289,8 +2211,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) return cfqd; out_crqpool: kfree(cfqd->cfq_hash); -out_cfqhash: - kfree(cfqd->crq_hash); out_crqhash: kfree(cfqd); return NULL; -- cgit v1.2.3 From 21183b07ee4be405362af8454f3647781c77df1b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 13 Jul 2006 12:33:14 +0200 Subject: [PATCH] cfq-iosched: migrate to using the elevator rb functions This removes the rbtree handling from CFQ. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 164 +++++++++++++--------------------------------------- 1 file changed, 41 insertions(+), 123 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 1b803c0c90f..b2fd8cac214 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -46,12 +46,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock); #define RQ_DATA(rq) (rq)->elevator_private -/* - * rb-tree defines - */ -#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) -#define rq_rb_key(rq) (rq)->sector - static kmem_cache_t *crq_pool; static kmem_cache_t *cfq_pool; static kmem_cache_t *cfq_ioc_pool; @@ -185,8 +179,6 @@ struct cfq_queue { }; struct cfq_rq { - struct rb_node rb_node; - sector_t rb_key; struct request *request; struct cfq_queue *cfq_queue; @@ -376,33 +368,27 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) */ static struct cfq_rq * cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *last) + struct cfq_rq *last_crq) { - struct cfq_rq *crq_next = NULL, *crq_prev = NULL; - struct rb_node *rbnext, *rbprev; - - if (!(rbnext = rb_next(&last->rb_node))) { - rbnext = rb_first(&cfqq->sort_list); - if (rbnext == &last->rb_node) - rbnext = NULL; - } + struct request *last = last_crq->request; + struct rb_node *rbnext = rb_next(&last->rb_node); + struct rb_node *rbprev = rb_prev(&last->rb_node); + struct cfq_rq *next = NULL, *prev = NULL; - rbprev = rb_prev(&last->rb_node); + BUG_ON(RB_EMPTY_NODE(&last->rb_node)); if (rbprev) - crq_prev = rb_entry_crq(rbprev); - if (rbnext) - crq_next = rb_entry_crq(rbnext); - - return cfq_choose_req(cfqd, crq_next, crq_prev); -} + prev = RQ_DATA(rb_entry_rq(rbprev)); -static void cfq_update_next_crq(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; + if (rbnext) + next = RQ_DATA(rb_entry_rq(rbnext)); + else { + rbnext = rb_first(&cfqq->sort_list); + if (rbnext && rbnext != &last->rb_node) + next = RQ_DATA(rb_entry_rq(rbnext)); + } - if (cfqq->next_crq == crq) - cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); + return cfq_choose_req(cfqd, next, prev); } static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) @@ -497,71 +483,34 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq) BUG_ON(!cfqq->queued[sync]); cfqq->queued[sync]--; - cfq_update_next_crq(crq); - - rb_erase(&crq->rb_node, &cfqq->sort_list); + elv_rb_del(&cfqq->sort_list, crq->request); if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) cfq_del_cfqq_rr(cfqd, cfqq); } -static struct cfq_rq * -__cfq_add_crq_rb(struct cfq_rq *crq) -{ - struct rb_node **p = &crq->cfq_queue->sort_list.rb_node; - struct rb_node *parent = NULL; - struct cfq_rq *__crq; - - while (*p) { - parent = *p; - __crq = rb_entry_crq(parent); - - if (crq->rb_key < __crq->rb_key) - p = &(*p)->rb_left; - else if (crq->rb_key > __crq->rb_key) - p = &(*p)->rb_right; - else - return __crq; - } - - rb_link_node(&crq->rb_node, parent, p); - return NULL; -} - static void cfq_add_crq_rb(struct cfq_rq *crq) { struct cfq_queue *cfqq = crq->cfq_queue; struct cfq_data *cfqd = cfqq->cfqd; struct request *rq = crq->request; - struct cfq_rq *__alias; + struct request *__alias; - crq->rb_key = rq_rb_key(rq); cfqq->queued[cfq_crq_is_sync(crq)]++; /* * looks a little odd, but the first insert might return an alias. * if that happens, put the alias on the dispatch list */ - while ((__alias = __cfq_add_crq_rb(crq)) != NULL) - cfq_dispatch_insert(cfqd->queue, __alias); - - rb_insert_color(&crq->rb_node, &cfqq->sort_list); - - if (!cfq_cfqq_on_rr(cfqq)) - cfq_add_cfqq_rr(cfqd, cfqq); - - /* - * check if this request is a better next-serve candidate - */ - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); + while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL) + cfq_dispatch_insert(cfqd->queue, RQ_DATA(__alias)); } static inline void cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) { - rb_erase(&crq->rb_node, &cfqq->sort_list); + elv_rb_del(&cfqq->sort_list, crq->request); cfqq->queued[cfq_crq_is_sync(crq)]--; - cfq_add_crq_rb(crq); } @@ -570,28 +519,13 @@ 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)); + sector_t sector = bio->bi_sector + bio_sectors(bio); struct cfq_queue *cfqq; - struct rb_node *n; - sector_t sector; cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); - if (!cfqq) - goto out; - - sector = bio->bi_sector + bio_sectors(bio); - n = cfqq->sort_list.rb_node; - while (n) { - struct cfq_rq *crq = rb_entry_crq(n); - - if (sector < crq->rb_key) - n = n->rb_left; - else if (sector > crq->rb_key) - n = n->rb_right; - else - return crq->request; - } + if (cfqq) + return elv_rb_find(&cfqq->sort_list, sector); -out: return NULL; } @@ -622,6 +556,10 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq) static void cfq_remove_request(struct request *rq) { struct cfq_rq *crq = RQ_DATA(rq); + struct cfq_queue *cfqq = crq->cfq_queue; + + if (cfqq->next_crq == crq) + cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); list_del_init(&rq->queuelist); cfq_del_crq_rb(crq); @@ -642,14 +580,14 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; } -static void cfq_merged_request(request_queue_t *q, struct request *req) +static void cfq_merged_request(request_queue_t *q, struct request *req, + int type) { struct cfq_rq *crq = RQ_DATA(req); - if (rq_rb_key(req) != crq->rb_key) { + if (type == ELEVATOR_FRONT_MERGE) { struct cfq_queue *cfqq = crq->cfq_queue; - cfq_update_next_crq(crq); cfq_reposition_crq_rb(cfqq, crq); } } @@ -658,8 +596,6 @@ static void cfq_merged_requests(request_queue_t *q, struct request *rq, struct request *next) { - cfq_merged_request(q, rq); - /* * reposition in fifo if next is older than rq */ @@ -881,7 +817,6 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) struct cfq_queue *cfqq = crq->cfq_queue; struct request *rq; - cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); cfq_remove_request(crq->request); cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; elv_dispatch_sort(q, crq->request); @@ -1699,6 +1634,12 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, { struct cfq_io_context *cic = crq->io_context; + /* + * check if this request is a better next-serve candidate + */ + cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); + BUG_ON(!cfqq->next_crq); + /* * we never wait for an async request and we don't allow preemption * of an async request. so just return early @@ -1756,6 +1697,9 @@ static void cfq_insert_request(request_queue_t *q, struct request *rq) cfq_add_crq_rb(crq); + if (!cfq_cfqq_on_rr(cfqq)) + cfq_add_cfqq_rr(cfqd, cfqq); + list_add_tail(&rq->queuelist, &cfqq->fifo); cfq_crq_enqueued(cfqd, cfqq, crq); @@ -1803,30 +1747,6 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq) } } -static struct request * -cfq_former_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbprev = rb_prev(&crq->rb_node); - - if (rbprev) - return rb_entry_crq(rbprev)->request; - - return NULL; -} - -static struct request * -cfq_latter_request(request_queue_t *q, struct request *rq) -{ - struct cfq_rq *crq = RQ_DATA(rq); - struct rb_node *rbnext = rb_next(&crq->rb_node); - - if (rbnext) - return rb_entry_crq(rbnext)->request; - - return NULL; -} - /* * we temporarily boost lower priority queues if they are holding fs exclusive * resources. they are boosted to normal prio (CLASS_BE/4) @@ -1982,8 +1902,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, crq = mempool_alloc(cfqd->crq_pool, gfp_mask); if (crq) { - RB_CLEAR_NODE(&crq->rb_node); - crq->rb_key = 0; crq->request = rq; crq->cfq_queue = cfqq; crq->io_context = cic; @@ -2345,8 +2263,8 @@ static struct elevator_type iosched_cfq = { .elevator_deactivate_req_fn = cfq_deactivate_request, .elevator_queue_empty_fn = cfq_queue_empty, .elevator_completed_req_fn = cfq_completed_request, - .elevator_former_req_fn = cfq_former_request, - .elevator_latter_req_fn = cfq_latter_request, + .elevator_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, -- cgit v1.2.3 From 95e8810b283cfac50789126de4207f9909299de9 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 11 Jul 2006 21:30:31 +0200 Subject: [PATCH] cfq-iosched: convert to using the FIFO elevator defines Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index b2fd8cac214..5e4bae7f415 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -42,7 +42,6 @@ static DEFINE_SPINLOCK(cfq_exit_lock); #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 list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist) #define RQ_DATA(rq) (rq)->elevator_private @@ -840,7 +839,7 @@ static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) if (!list_empty(&cfqq->fifo)) { int fifo = cfq_cfqq_class_sync(cfqq); - crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next)); + crq = RQ_DATA(rq_entry_fifo(cfqq->fifo.next)); rq = crq->request; if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { cfq_mark_cfqq_fifo_expire(cfqq); -- cgit v1.2.3 From 5380a101d33d1d3a32c6b6bd2e17e5dd835842b0 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 13 Jul 2006 12:37:56 +0200 Subject: [PATCH] cfq-iosched: remove the crq flag functions/variable There's just one flag currently (SYNC), and that one can be grabbed from the request. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 58 +++++++++++++++-------------------------------------- 1 file changed, 16 insertions(+), 42 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 5e4bae7f415..86f0f4796fd 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -182,8 +182,6 @@ struct cfq_rq { struct cfq_queue *cfq_queue; struct cfq_io_context *io_context; - - unsigned int crq_flags; }; enum cfqq_state_flags { @@ -221,27 +219,6 @@ CFQ_CFQQ_FNS(idle_window); CFQ_CFQQ_FNS(prio_changed); #undef CFQ_CFQQ_FNS -enum cfq_rq_state_flags { - CFQ_CRQ_FLAG_is_sync = 0, -}; - -#define CFQ_CRQ_FNS(name) \ -static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \ -{ \ - crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \ -} \ -static inline int cfq_crq_##name(const struct cfq_rq *crq) \ -{ \ - return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ -} - -CFQ_CRQ_FNS(is_sync); -#undef CFQ_CRQ_FNS - static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask); @@ -290,9 +267,9 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) if (crq2 == NULL) return crq1; - if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) + if (rq_is_sync(crq1->request) && !rq_is_sync(crq2->request)) return crq1; - else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) + else if (rq_is_sync(crq2->request) && !rq_is_sync(crq1->request)) return crq2; s1 = crq1->request->sector; @@ -477,7 +454,7 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq) { struct cfq_queue *cfqq = crq->cfq_queue; struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); + const int sync = rq_is_sync(crq->request); BUG_ON(!cfqq->queued[sync]); cfqq->queued[sync]--; @@ -495,7 +472,7 @@ static void cfq_add_crq_rb(struct cfq_rq *crq) struct request *rq = crq->request; struct request *__alias; - cfqq->queued[cfq_crq_is_sync(crq)]++; + cfqq->queued[rq_is_sync(rq)]++; /* * looks a little odd, but the first insert might return an alias. @@ -508,8 +485,10 @@ static void cfq_add_crq_rb(struct cfq_rq *crq) static inline void cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) { - elv_rb_del(&cfqq->sort_list, crq->request); - cfqq->queued[cfq_crq_is_sync(crq)]--; + struct request *rq = crq->request; + + elv_rb_del(&cfqq->sort_list, rq); + cfqq->queued[rq_is_sync(rq)]--; cfq_add_crq_rb(crq); } @@ -814,11 +793,11 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) { struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq = crq->cfq_queue; - struct request *rq; + struct request *rq = crq->request; - cfq_remove_request(crq->request); - cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; - elv_dispatch_sort(q, crq->request); + 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; @@ -1585,7 +1564,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, */ if (new_cfqq->slice_left < cfqd->cfq_slice_idle) return 0; - if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq)) + if (rq_is_sync(crq->request) && !cfq_cfqq_sync(cfqq)) return 1; return 0; @@ -1634,7 +1613,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct cfq_io_context *cic = crq->io_context; /* - * check if this request is a better next-serve candidate + * check if this request is a better next-serve candidate)) { */ cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); BUG_ON(!cfqq->next_crq); @@ -1643,7 +1622,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, * we never wait for an async request and we don't allow preemption * of an async request. so just return early */ - if (!cfq_crq_is_sync(crq)) { + if (!rq_is_sync(crq->request)) { /* * sync process issued an async request, if it's waiting * then expire it and kick rq handling. @@ -1709,7 +1688,7 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq) struct cfq_rq *crq = RQ_DATA(rq); struct cfq_queue *cfqq = crq->cfq_queue; struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); + const int sync = rq_is_sync(rq); unsigned long now; now = jiffies; @@ -1905,11 +1884,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, crq->cfq_queue = cfqq; crq->io_context = cic; - if (is_sync) - cfq_mark_crq_is_sync(crq); - else - cfq_clear_crq_is_sync(crq); - rq->elevator_private = crq; return 0; } -- cgit v1.2.3 From 5e705374796e72b36e7bb9c59c8d46d2dc5db36a Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 13 Jul 2006 12:39:25 +0200 Subject: [PATCH] cfq-iosched: kill crq Get rid of the cfq_rq request type. With the added elevator_private2, we have enough room in struct request to get rid of any crq allocation/free for each request. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 239 +++++++++++++++++++++------------------------------- 1 file changed, 95 insertions(+), 144 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 86f0f4796fd..3c5fd9c2c20 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -43,9 +43,9 @@ static DEFINE_SPINLOCK(cfq_exit_lock); #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) -#define RQ_DATA(rq) (rq)->elevator_private +#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private) +#define RQ_CFQQ(rq) ((rq)->elevator_private2) -static kmem_cache_t *crq_pool; static kmem_cache_t *cfq_pool; static kmem_cache_t *cfq_ioc_pool; @@ -95,8 +95,6 @@ struct cfq_data { */ struct hlist_head *cfq_hash; - mempool_t *crq_pool; - int rq_in_driver; int hw_tag; @@ -153,7 +151,7 @@ struct cfq_queue { /* sorted list of pending requests */ struct rb_root sort_list; /* if fifo isn't expired, next request to serve */ - struct cfq_rq *next_crq; + struct request *next_rq; /* requests queued in sort_list */ int queued[2]; /* currently allocated requests */ @@ -177,13 +175,6 @@ struct cfq_queue { unsigned int flags; }; -struct cfq_rq { - struct request *request; - - struct cfq_queue *cfq_queue; - struct cfq_io_context *io_context; -}; - enum cfqq_state_flags { CFQ_CFQQ_FLAG_on_rr = 0, CFQ_CFQQ_FLAG_wait_request, @@ -220,7 +211,7 @@ CFQ_CFQQ_FNS(prio_changed); #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 cfq_rq *); +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); /* @@ -249,12 +240,12 @@ static inline pid_t cfq_queue_pid(struct task_struct *task, int rw) } /* - * Lifted from AS - choose which of crq1 and crq2 that is best served now. + * 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 cfq_rq * -cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) +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; @@ -262,18 +253,18 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */ unsigned wrap = 0; /* bit mask: requests behind the disk head? */ - if (crq1 == NULL || crq1 == crq2) - return crq2; - if (crq2 == NULL) - return crq1; + if (rq1 == NULL || rq1 == rq2) + return rq2; + if (rq2 == NULL) + return rq1; - if (rq_is_sync(crq1->request) && !rq_is_sync(crq2->request)) - return crq1; - else if (rq_is_sync(crq2->request) && !rq_is_sync(crq1->request)) - return crq2; + if (rq_is_sync(rq1) && !rq_is_sync(rq2)) + return rq1; + else if (rq_is_sync(rq2) && !rq_is_sync(rq1)) + return rq2; - s1 = crq1->request->sector; - s2 = crq2->request->sector; + s1 = rq1->sector; + s2 = rq2->sector; last = cfqd->last_sector; @@ -308,23 +299,23 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) * check two variables for all permutations: --> faster! */ switch (wrap) { - case 0: /* common case for CFQ: crq1 and crq2 not wrapped */ + case 0: /* common case for CFQ: rq1 and rq2 not wrapped */ if (d1 < d2) - return crq1; + return rq1; else if (d2 < d1) - return crq2; + return rq2; else { if (s1 >= s2) - return crq1; + return rq1; else - return crq2; + return rq2; } case CFQ_RQ2_WRAP: - return crq1; + return rq1; case CFQ_RQ1_WRAP: - return crq2; - case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */ + return rq2; + case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */ default: /* * Since both rqs are wrapped, @@ -333,35 +324,34 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) * since back seek takes more time than forward. */ if (s1 <= s2) - return crq1; + return rq1; else - return crq2; + return rq2; } } /* * would be nice to take fifo expire time into account as well */ -static struct cfq_rq * -cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *last_crq) +static struct request * +cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, + struct request *last) { - struct request *last = last_crq->request; struct rb_node *rbnext = rb_next(&last->rb_node); struct rb_node *rbprev = rb_prev(&last->rb_node); - struct cfq_rq *next = NULL, *prev = NULL; + struct request *next = NULL, *prev = NULL; BUG_ON(RB_EMPTY_NODE(&last->rb_node)); if (rbprev) - prev = RQ_DATA(rb_entry_rq(rbprev)); + prev = rb_entry_rq(rbprev); if (rbnext) - next = RQ_DATA(rb_entry_rq(rbnext)); + next = rb_entry_rq(rbnext); else { rbnext = rb_first(&cfqq->sort_list); if (rbnext && rbnext != &last->rb_node) - next = RQ_DATA(rb_entry_rq(rbnext)); + next = rb_entry_rq(rbnext); } return cfq_choose_req(cfqd, next, prev); @@ -450,26 +440,25 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) /* * rb tree support functions */ -static inline void cfq_del_crq_rb(struct cfq_rq *crq) +static inline void cfq_del_rq_rb(struct request *rq) { - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(rq); struct cfq_data *cfqd = cfqq->cfqd; - const int sync = rq_is_sync(crq->request); + const int sync = rq_is_sync(rq); BUG_ON(!cfqq->queued[sync]); cfqq->queued[sync]--; - elv_rb_del(&cfqq->sort_list, crq->request); + 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_crq_rb(struct cfq_rq *crq) +static void cfq_add_rq_rb(struct request *rq) { - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(rq); struct cfq_data *cfqd = cfqq->cfqd; - struct request *rq = crq->request; struct request *__alias; cfqq->queued[rq_is_sync(rq)]++; @@ -479,17 +468,15 @@ static void cfq_add_crq_rb(struct cfq_rq *crq) * 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, RQ_DATA(__alias)); + cfq_dispatch_insert(cfqd->queue, __alias); } static inline void -cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq) +cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq) { - struct request *rq = crq->request; - elv_rb_del(&cfqq->sort_list, rq); cfqq->queued[rq_is_sync(rq)]--; - cfq_add_crq_rb(crq); + cfq_add_rq_rb(rq); } static struct request * @@ -533,14 +520,13 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq) static void cfq_remove_request(struct request *rq) { - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(rq); - if (cfqq->next_crq == crq) - cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq); + if (cfqq->next_rq == rq) + cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq); list_del_init(&rq->queuelist); - cfq_del_crq_rb(crq); + cfq_del_rq_rb(rq); } static int @@ -561,12 +547,10 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) static void cfq_merged_request(request_queue_t *q, struct request *req, int type) { - struct cfq_rq *crq = RQ_DATA(req); - if (type == ELEVATOR_FRONT_MERGE) { - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(req); - cfq_reposition_crq_rb(cfqq, crq); + cfq_reposition_rq_rb(cfqq, req); } } @@ -789,11 +773,10 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) return 1; } -static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) +static void cfq_dispatch_insert(request_queue_t *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_queue *cfqq = crq->cfq_queue; - struct request *rq = crq->request; + struct cfq_queue *cfqq = RQ_CFQQ(rq); cfq_remove_request(rq); cfqq->on_dispatch[rq_is_sync(rq)]++; @@ -806,11 +789,10 @@ static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq) /* * return expired entry, or NULL to just start from scratch in rbtree */ -static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) +static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq) { struct cfq_data *cfqd = cfqq->cfqd; struct request *rq; - struct cfq_rq *crq; if (cfq_cfqq_fifo_expire(cfqq)) return NULL; @@ -818,11 +800,10 @@ static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq) if (!list_empty(&cfqq->fifo)) { int fifo = cfq_cfqq_class_sync(cfqq); - crq = RQ_DATA(rq_entry_fifo(cfqq->fifo.next)); - rq = crq->request; + 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 crq; + return rq; } } @@ -909,25 +890,25 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list)); do { - struct cfq_rq *crq; + struct request *rq; /* * follow expired path, else get first next available */ - if ((crq = cfq_check_fifo(cfqq)) == NULL) - crq = cfqq->next_crq; + if ((rq = cfq_check_fifo(cfqq)) == NULL) + rq = cfqq->next_rq; /* * finally, insert request into driver dispatch list */ - cfq_dispatch_insert(cfqd->queue, crq); + cfq_dispatch_insert(cfqd->queue, rq); cfqd->dispatch_slice++; dispatched++; if (!cfqd->active_cic) { - atomic_inc(&crq->io_context->ioc->refcount); - cfqd->active_cic = crq->io_context; + atomic_inc(&RQ_CIC(rq)->ioc->refcount); + cfqd->active_cic = RQ_CIC(rq); } if (RB_EMPTY_ROOT(&cfqq->sort_list)) @@ -958,13 +939,12 @@ static int cfq_forced_dispatch_cfqqs(struct list_head *list) { struct cfq_queue *cfqq, *next; - struct cfq_rq *crq; int dispatched; dispatched = 0; list_for_each_entry_safe(cfqq, next, list, cfq_list) { - while ((crq = cfqq->next_crq)) { - cfq_dispatch_insert(cfqq->cfqd->queue, crq); + while (cfqq->next_rq) { + cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq); dispatched++; } BUG_ON(!list_empty(&cfqq->fifo)); @@ -1040,8 +1020,8 @@ cfq_dispatch_requests(request_queue_t *q, int force) } /* - * task holds one reference to the queue, dropped when task exits. each crq - * in-flight on this queue also holds a reference, dropped when crq is freed. + * 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. */ @@ -1486,15 +1466,15 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) static void cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic, - struct cfq_rq *crq) + struct request *rq) { sector_t sdist; u64 total; - if (cic->last_request_pos < crq->request->sector) - sdist = crq->request->sector - cic->last_request_pos; + if (cic->last_request_pos < rq->sector) + sdist = rq->sector - cic->last_request_pos; else - sdist = cic->last_request_pos - crq->request->sector; + sdist = cic->last_request_pos - rq->sector; /* * Don't allow the seek distance to get too large from the @@ -1545,7 +1525,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, */ static int cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, - struct cfq_rq *crq) + struct request *rq) { struct cfq_queue *cfqq = cfqd->active_queue; @@ -1564,7 +1544,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, */ if (new_cfqq->slice_left < cfqd->cfq_slice_idle) return 0; - if (rq_is_sync(crq->request) && !cfq_cfqq_sync(cfqq)) + if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq)) return 1; return 0; @@ -1603,26 +1583,26 @@ static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) } /* - * Called when a new fs request (crq) is added (to cfqq). Check if there's + * Called when a new fs request (rq) is added (to cfqq). Check if there's * something we should do about it */ static void -cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct cfq_rq *crq) +cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, + struct request *rq) { - struct cfq_io_context *cic = crq->io_context; + struct cfq_io_context *cic = RQ_CIC(rq); /* * check if this request is a better next-serve candidate)) { */ - cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq); - BUG_ON(!cfqq->next_crq); + 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(crq->request)) { + if (!rq_is_sync(rq)) { /* * sync process issued an async request, if it's waiting * then expire it and kick rq handling. @@ -1636,11 +1616,11 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, } cfq_update_io_thinktime(cfqd, cic); - cfq_update_io_seektime(cfqd, cic, crq); + cfq_update_io_seektime(cfqd, cic, rq); cfq_update_idle_window(cfqd, cfqq, cic); cic->last_queue = jiffies; - cic->last_request_pos = crq->request->sector + crq->request->nr_sectors; + cic->last_request_pos = rq->sector + rq->nr_sectors; if (cfqq == cfqd->active_queue) { /* @@ -1653,7 +1633,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, del_timer(&cfqd->idle_slice_timer); cfq_start_queueing(cfqd, cfqq); } - } else if (cfq_should_preempt(cfqd, cfqq, crq)) { + } 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 @@ -1668,25 +1648,23 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, static void cfq_insert_request(request_queue_t *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(rq); cfq_init_prio_data(cfqq); - cfq_add_crq_rb(crq); + 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_crq_enqueued(cfqd, cfqq, crq); + cfq_rq_enqueued(cfqd, cfqq, rq); } static void cfq_completed_request(request_queue_t *q, struct request *rq) { - struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_queue *cfqq = RQ_CFQQ(rq); struct cfq_data *cfqd = cfqq->cfqd; const int sync = rq_is_sync(rq); unsigned long now; @@ -1709,7 +1687,7 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq) } if (sync) - crq->io_context->last_end_request = now; + RQ_CIC(rq)->last_end_request = now; /* * If this is the active queue, check if it needs to be expired, @@ -1817,20 +1795,18 @@ static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) */ static void cfq_put_request(request_queue_t *q, struct request *rq) { - struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); + struct cfq_queue *cfqq = RQ_CFQQ(rq); - if (crq) { - struct cfq_queue *cfqq = crq->cfq_queue; + if (cfqq) { const int rw = rq_data_dir(rq); BUG_ON(!cfqq->allocated[rw]); cfqq->allocated[rw]--; - put_io_context(crq->io_context->ioc); + put_io_context(RQ_CIC(rq)->ioc); - mempool_free(crq, cfqd->crq_pool); rq->elevator_private = NULL; + rq->elevator_private2 = NULL; cfq_check_waiters(q, cfqq); cfq_put_queue(cfqq); @@ -1850,7 +1826,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, const int rw = rq_data_dir(rq); pid_t key = cfq_queue_pid(tsk, rw); struct cfq_queue *cfqq; - struct cfq_rq *crq; unsigned long flags; int is_sync = key != CFQ_KEY_ASYNC; @@ -1876,23 +1851,13 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, cfq_clear_cfqq_must_alloc(cfqq); cfqd->rq_starved = 0; atomic_inc(&cfqq->ref); - spin_unlock_irqrestore(q->queue_lock, flags); - crq = mempool_alloc(cfqd->crq_pool, gfp_mask); - if (crq) { - crq->request = rq; - crq->cfq_queue = cfqq; - crq->io_context = cic; + spin_unlock_irqrestore(q->queue_lock, flags); - rq->elevator_private = crq; - return 0; - } + rq->elevator_private = cic; + rq->elevator_private2 = cfqq; + return 0; - spin_lock_irqsave(q->queue_lock, flags); - cfqq->allocated[rw]--; - if (!(cfqq->allocated[0] + cfqq->allocated[1])) - cfq_mark_cfqq_must_alloc(cfqq); - cfq_put_queue(cfqq); queue_fail: if (cic) put_io_context(cic->ioc); @@ -2040,7 +2005,6 @@ static void cfq_exit_queue(elevator_t *e) cfq_shutdown_timer_wq(cfqd); - mempool_destroy(cfqd->crq_pool); kfree(cfqd->cfq_hash); kfree(cfqd); } @@ -2067,11 +2031,7 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); if (!cfqd->cfq_hash) - goto out_crqhash; - - cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool); - if (!cfqd->crq_pool) - goto out_crqpool; + goto out_free; for (i = 0; i < CFQ_QHASH_ENTRIES; i++) INIT_HLIST_HEAD(&cfqd->cfq_hash[i]); @@ -2100,17 +2060,13 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) cfqd->cfq_slice_idle = cfq_slice_idle; return cfqd; -out_crqpool: - kfree(cfqd->cfq_hash); -out_crqhash: +out_free: kfree(cfqd); return NULL; } static void cfq_slab_kill(void) { - if (crq_pool) - kmem_cache_destroy(crq_pool); if (cfq_pool) kmem_cache_destroy(cfq_pool); if (cfq_ioc_pool) @@ -2119,11 +2075,6 @@ static void cfq_slab_kill(void) static int __init cfq_slab_setup(void) { - crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0, - NULL, NULL); - if (!crq_pool) - goto fail; - cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0, NULL, NULL); if (!cfq_pool) -- cgit v1.2.3 From cb78b285c8f9d59b0d4e4f6a54c2977ce1d9b880 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 28 Jul 2006 09:32:57 +0200 Subject: [PATCH] Drop useless bio passing in may_queue/set_request API It's not needed for anything, so kill the bio passing. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 3c5fd9c2c20..2ac35aacbbf 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1752,7 +1752,7 @@ __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, return ELV_MQUEUE_MAY; } -static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio) +static int cfq_may_queue(request_queue_t *q, int rw) { struct cfq_data *cfqd = q->elevator->elevator_data; struct task_struct *tsk = current; @@ -1817,8 +1817,7 @@ static void cfq_put_request(request_queue_t *q, struct request *rq) * Allocate cfq data structures associated with this request. */ static int -cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, - gfp_t gfp_mask) +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; -- cgit v1.2.3 From 89850f7ee905410c89f9295e89dc4c33502a34ac Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 22 Jul 2006 16:48:31 +0200 Subject: [PATCH] cfq-iosched: cleanups, fixes, dead code removal A collection of little fixes and cleanups: - We don't use the 'queued' sysfs exported attribute, since the may_queue() logic was rewritten. So kill it. - Remove dead defines. - cfq_set_active_queue() can be rewritten cleaner with else if conditions. - Several places had cfq_exit_cfqq() like logic, abstract that out and use that. - Annotate the cfqq kmem_cache_alloc() so the allocator knows that this is a repeat allocation if it fails with __GFP_WAIT set. Allows the allocator to start freeing some memory, if needed. CFQ already loops for this condition, so might as well pass the hint down. - Remove cfqd->rq_starved logic. It's not needed anymore after we dropped the crq allocation in cfq_set_request(). - Remove uneeded parameter passing. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 184 ++++++++++++++++++++-------------------------------- 1 file changed, 70 insertions(+), 114 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 2ac35aacbbf..ec24284e9d3 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -17,7 +17,6 @@ * tunables */ static const int cfq_quantum = 4; /* max queue in one round of service */ -static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 }; static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */ static const int cfq_back_penalty = 2; /* penalty of a backwards seek */ @@ -54,7 +53,6 @@ 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_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) #define ASYNC (0) @@ -98,9 +96,6 @@ struct cfq_data { int rq_in_driver; int hw_tag; - /* - * schedule slice state info - */ /* * idle window management */ @@ -117,13 +112,10 @@ struct cfq_data { sector_t last_sector; unsigned long last_end_request; - unsigned int rq_starved; - /* * tunables, see top of file */ unsigned int cfq_quantum; - unsigned int cfq_queued; unsigned int cfq_fifo_expire[2]; unsigned int cfq_back_penalty; unsigned int cfq_back_max; @@ -484,12 +476,14 @@ 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)); - sector_t sector = bio->bi_sector + bio_sectors(bio); struct cfq_queue *cfqq; cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); - if (cfqq) + if (cfqq) { + sector_t sector = bio->bi_sector + bio_sectors(bio); + return elv_rb_find(&cfqq->sort_list, sector); + } return NULL; } @@ -699,26 +693,25 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) { struct cfq_queue *cfqq = NULL; - /* - * if current list is non-empty, grab first entry. if it is empty, - * get next prio level and grab first entry then if any are spliced - */ - if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) + 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); - - /* - * If no new queues are available, check if the busy list has some - * before falling back to idle io. - */ - if (!cfqq && !list_empty(&cfqd->busy_rr)) + } 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); - - /* - * if we have idle queues and no rt or be queues had pending - * requests, either allow immediate service if the grace period - * has passed or arm the idle grace timer - */ - if (!cfqq && !list_empty(&cfqd->idle_rr)) { + } 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)) @@ -793,18 +786,19 @@ 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; - if (!list_empty(&cfqq->fifo)) { - int fifo = cfq_cfqq_class_sync(cfqq); + fifo = cfq_cfqq_class_sync(cfqq); + rq = rq_entry_fifo(cfqq->fifo.next); - 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; - } + if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { + cfq_mark_cfqq_fifo_expire(cfqq); + return rq; } return NULL; @@ -1096,40 +1090,48 @@ static void cfq_trim(struct io_context *ioc) cfq_free_io_context(ioc); } -/* - * Called with interrupts disabled - */ -static void cfq_exit_single_io_context(struct cfq_io_context *cic) +static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) { - struct cfq_data *cfqd = cic->key; - request_queue_t *q; - - if (!cfqd) - return; - - q = cfqd->queue; - - WARN_ON(!irqs_disabled()); + if (unlikely(cfqq == cfqd->active_queue)) + __cfq_slice_expired(cfqd, cfqq, 0); - spin_lock(q->queue_lock); + cfq_put_queue(cfqq); +} +static void __cfq_exit_single_io_context(struct cfq_data *cfqd, + struct cfq_io_context *cic) +{ if (cic->cfqq[ASYNC]) { - if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) - __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); - cfq_put_queue(cic->cfqq[ASYNC]); + cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); cic->cfqq[ASYNC] = NULL; } if (cic->cfqq[SYNC]) { - if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) - __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); - cfq_put_queue(cic->cfqq[SYNC]); + cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); cic->cfqq[SYNC] = NULL; } cic->key = NULL; list_del_init(&cic->queue_list); - spin_unlock(q->queue_lock); +} + + +/* + * Called with interrupts disabled + */ +static void cfq_exit_single_io_context(struct cfq_io_context *cic) +{ + struct cfq_data *cfqd = cic->key; + + WARN_ON(!irqs_disabled()); + + if (cfqd) { + request_queue_t *q = cfqd->queue; + + spin_lock(q->queue_lock); + __cfq_exit_single_io_context(cfqd, cic); + spin_unlock(q->queue_lock); + } } static void cfq_exit_io_context(struct io_context *ioc) @@ -1286,8 +1288,14 @@ retry: 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(cfq_pool, gfp_mask); + new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask|__GFP_NOFAIL); spin_lock_irq(cfqd->queue->queue_lock); goto retry; } else { @@ -1739,9 +1747,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq) cfq_resort_rr_list(cfqq, 0); } -static inline int -__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct task_struct *task, int rw) +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)) { @@ -1769,27 +1775,12 @@ static int cfq_may_queue(request_queue_t *q, int rw) cfq_init_prio_data(cfqq); cfq_prio_boost(cfqq); - return __cfq_may_queue(cfqd, cfqq, tsk, rw); + return __cfq_may_queue(cfqq); } return ELV_MQUEUE_MAY; } -static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - if (unlikely(cfqd->rq_starved)) { - struct request_list *rl = &q->rq; - - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } -} - /* * queue lock held here */ @@ -1808,7 +1799,6 @@ static void cfq_put_request(request_queue_t *q, struct request *rq) rq->elevator_private = NULL; rq->elevator_private2 = NULL; - cfq_check_waiters(q, cfqq); cfq_put_queue(cfqq); } } @@ -1848,7 +1838,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) cfqq->allocated[rw]++; cfq_clear_cfqq_must_alloc(cfqq); - cfqd->rq_starved = 0; atomic_inc(&cfqq->ref); spin_unlock_irqrestore(q->queue_lock, flags); @@ -1860,12 +1849,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) queue_fail: if (cic) put_io_context(cic->ioc); - /* - * mark us rq allocation starved. we need to kickstart the process - * ourselves if there are no pending requests that can do it for us. - * that would be an extremely rare OOM situation - */ - cfqd->rq_starved = 1; + cfq_schedule_dispatch(cfqd); spin_unlock_irqrestore(q->queue_lock, flags); return 1; @@ -1874,25 +1858,9 @@ queue_fail: static void cfq_kick_queue(void *data) { request_queue_t *q = data; - struct cfq_data *cfqd = q->elevator->elevator_data; unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - - if (cfqd->rq_starved) { - struct request_list *rl = &q->rq; - - /* - * we aren't guaranteed to get a request after this, but we - * have to be opportunistic - */ - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } - blk_remove_plug(q); q->request_fn(q); spin_unlock_irqrestore(q->queue_lock, flags); @@ -1987,16 +1955,8 @@ static void cfq_exit_queue(elevator_t *e) struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, struct cfq_io_context, queue_list); - if (cic->cfqq[ASYNC]) { - cfq_put_queue(cic->cfqq[ASYNC]); - cic->cfqq[ASYNC] = NULL; - } - if (cic->cfqq[SYNC]) { - cfq_put_queue(cic->cfqq[SYNC]); - cic->cfqq[SYNC] = NULL; - } - cic->key = NULL; - list_del_init(&cic->queue_list); + + __cfq_exit_single_io_context(cfqd, cic); } spin_unlock_irq(q->queue_lock); @@ -2047,7 +2007,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); - cfqd->cfq_queued = cfq_queued; cfqd->cfq_quantum = cfq_quantum; cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; @@ -2119,7 +2078,6 @@ static ssize_t __FUNC(elevator_t *e, char *page) \ return cfq_var_show(__data, (page)); \ } SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); -SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0); SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1); SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1); SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0); @@ -2147,7 +2105,6 @@ static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ return ret; \ } STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0); STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1); STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1); STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0); @@ -2163,7 +2120,6 @@ STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, static struct elv_fs_entry cfq_attrs[] = { CFQ_ATTR(quantum), - CFQ_ATTR(queued), CFQ_ATTR(fifo_expire_sync), CFQ_ATTR(fifo_expire_async), CFQ_ATTR(back_seek_max), -- cgit v1.2.3 From fc46379daf90dce57bf765c81d3b39f55150aac2 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 29 Aug 2006 09:05:44 +0200 Subject: [PATCH] cfq-iosched: kill cfq_exit_lock cfq_exit_lock is protecting two things now: - The per-ioc rbtree of cfq_io_contexts - The per-cfqd linked list of cfq_io_contexts The per-cfqd linked list can be protected by the queue lock, as it is (by definition) per cfqd as the queue lock is. The per-ioc rbtree is mainly used and updated by the process itself only. The only outside use is the io priority changing. If we move the priority changing to not browsing the rbtree, we can remove any locking from the rbtree updates and lookup completely. Let the sys_ioprio syscall just mark processes as having the iopriority changed and lazily update the private cfq io contexts the next time io is queued, and we can remove this locking as well. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 54 +++++++++++++++++------------------------------------ 1 file changed, 17 insertions(+), 37 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index ec24284e9d3..33e0b0c5e31 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -31,8 +31,6 @@ static int cfq_slice_idle = HZ / 125; #define CFQ_KEY_ASYNC (0) -static DEFINE_SPINLOCK(cfq_exit_lock); - /* * for the hash of cfqq inside the cfqd */ @@ -1084,12 +1082,6 @@ static void cfq_free_io_context(struct io_context *ioc) complete(ioc_gone); } -static void cfq_trim(struct io_context *ioc) -{ - ioc->set_ioprio = NULL; - cfq_free_io_context(ioc); -} - static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) { if (unlikely(cfqq == cfqd->active_queue)) @@ -1101,6 +1093,10 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_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; @@ -1110,9 +1106,6 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd, cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); cic->cfqq[SYNC] = NULL; } - - cic->key = NULL; - list_del_init(&cic->queue_list); } @@ -1123,27 +1116,23 @@ static void cfq_exit_single_io_context(struct cfq_io_context *cic) { struct cfq_data *cfqd = cic->key; - WARN_ON(!irqs_disabled()); - if (cfqd) { request_queue_t *q = cfqd->queue; - spin_lock(q->queue_lock); + spin_lock_irq(q->queue_lock); __cfq_exit_single_io_context(cfqd, cic); - spin_unlock(q->queue_lock); + spin_unlock_irq(q->queue_lock); } } static void cfq_exit_io_context(struct io_context *ioc) { struct cfq_io_context *__cic; - unsigned long flags; struct rb_node *n; /* * put the reference this task is holding to the various queues */ - spin_lock_irqsave(&cfq_exit_lock, flags); n = rb_first(&ioc->cic_root); while (n != NULL) { @@ -1152,8 +1141,6 @@ static void cfq_exit_io_context(struct io_context *ioc) cfq_exit_single_io_context(__cic); n = rb_next(n); } - - spin_unlock_irqrestore(&cfq_exit_lock, flags); } static struct cfq_io_context * @@ -1248,15 +1235,12 @@ static inline void changed_ioprio(struct cfq_io_context *cic) spin_unlock(cfqd->queue->queue_lock); } -/* - * callback from sys_ioprio_set, irqs are disabled - */ -static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) +static void cfq_ioc_set_ioprio(struct io_context *ioc) { struct cfq_io_context *cic; struct rb_node *n; - spin_lock(&cfq_exit_lock); + ioc->ioprio_changed = 0; n = rb_first(&ioc->cic_root); while (n != NULL) { @@ -1265,10 +1249,6 @@ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) changed_ioprio(cic); n = rb_next(n); } - - spin_unlock(&cfq_exit_lock); - - return 0; } static struct cfq_queue * @@ -1336,10 +1316,8 @@ out: static void cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic) { - spin_lock(&cfq_exit_lock); + WARN_ON(!list_empty(&cic->queue_list)); rb_erase(&cic->rb_node, &ioc->cic_root); - list_del_init(&cic->queue_list); - spin_unlock(&cfq_exit_lock); kmem_cache_free(cfq_ioc_pool, cic); atomic_dec(&ioc_count); } @@ -1385,7 +1363,6 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc, cic->ioc = ioc; cic->key = cfqd; - ioc->set_ioprio = cfq_ioc_set_ioprio; restart: parent = NULL; p = &ioc->cic_root.rb_node; @@ -1407,11 +1384,12 @@ restart: BUG(); } - spin_lock(&cfq_exit_lock); 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(&cfq_exit_lock); + spin_unlock_irq(cfqd->queue->queue_lock); } /* @@ -1441,6 +1419,10 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) 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); @@ -1945,7 +1927,6 @@ static void cfq_exit_queue(elevator_t *e) cfq_shutdown_timer_wq(cfqd); - spin_lock(&cfq_exit_lock); spin_lock_irq(q->queue_lock); if (cfqd->active_queue) @@ -1960,7 +1941,6 @@ static void cfq_exit_queue(elevator_t *e) } spin_unlock_irq(q->queue_lock); - spin_unlock(&cfq_exit_lock); cfq_shutdown_timer_wq(cfqd); @@ -2149,7 +2129,7 @@ static struct elevator_type iosched_cfq = { .elevator_may_queue_fn = cfq_may_queue, .elevator_init_fn = cfq_init_queue, .elevator_exit_fn = cfq_exit_queue, - .trim = cfq_trim, + .trim = cfq_free_io_context, }, .elevator_attrs = cfq_attrs, .elevator_name = "cfq", -- cgit v1.2.3 From 4050cf1674c632c73801a561689543d4887df2ef Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 19 Jul 2006 05:07:12 +0200 Subject: [PATCH] cfq-iosched: use new io context counting mechanism It's ok if the read path is a lot more costly, as long as inc/dec is really cheap. The inc/dec will happen for each created/freed io context, while the reading only happens when a disk queue exits. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 33e0b0c5e31..c988aa75dd5 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -46,7 +46,7 @@ static int cfq_slice_idle = HZ / 125; static kmem_cache_t *cfq_pool; static kmem_cache_t *cfq_ioc_pool; -static atomic_t ioc_count = ATOMIC_INIT(0); +static DEFINE_PER_CPU(unsigned long, ioc_count); static struct completion *ioc_gone; #define CFQ_PRIO_LISTS IOPRIO_BE_NR @@ -1078,7 +1078,9 @@ static void cfq_free_io_context(struct io_context *ioc) freed++; } - if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone) + elv_ioc_count_mod(ioc_count, -freed); + + if (ioc_gone && !elv_ioc_count_read(ioc_count)) complete(ioc_gone); } @@ -1154,7 +1156,7 @@ cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) INIT_LIST_HEAD(&cic->queue_list); cic->dtor = cfq_free_io_context; cic->exit = cfq_exit_io_context; - atomic_inc(&ioc_count); + elv_ioc_count_inc(ioc_count); } return cic; @@ -1319,7 +1321,7 @@ 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); - atomic_dec(&ioc_count); + elv_ioc_count_dec(ioc_count); } static struct cfq_io_context * @@ -2165,7 +2167,7 @@ static void __exit cfq_exit(void) ioc_gone = &all_gone; /* ioc_gone's update must be visible before reading ioc_count */ smp_wmb(); - if (atomic_read(&ioc_count)) + if (elv_ioc_count_read(ioc_count)) wait_for_completion(ioc_gone); synchronize_rcu(); cfq_slab_kill(); -- cgit v1.2.3 From 1ea25ecb7256978947c258f08a30c878eebe9edb Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 18 Jul 2006 22:24:11 +0200 Subject: [PATCH] Audit block layer inlines Kill a few inlines that bring in too much code to more than one location Shrinks kernel text by about 300 bytes on 32-bit x86. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index c988aa75dd5..85f1d87e86d 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1041,7 +1041,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq) kmem_cache_free(cfq_pool, cfqq); } -static inline struct cfq_queue * +static struct cfq_queue * __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio, const int hashval) { -- cgit v1.2.3 From b5deef901282628d88c784f4c9d2f0583ec3b355 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 19 Jul 2006 23:39:40 +0200 Subject: [PATCH] Make sure all block/io scheduler setups are node aware Some were kmalloc_node(), some were still kmalloc(). Change them all to kmalloc_node(). Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 85f1d87e86d..0452108a932 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1148,8 +1148,9 @@ static void cfq_exit_io_context(struct io_context *ioc) static struct cfq_io_context * cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) { - struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask); + 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; @@ -1277,11 +1278,11 @@ retry: * free memory. */ spin_unlock_irq(cfqd->queue->queue_lock); - new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask|__GFP_NOFAIL); + 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(cfq_pool, gfp_mask); + cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node); if (!cfqq) goto out; } @@ -1407,7 +1408,7 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask) might_sleep_if(gfp_mask & __GFP_WAIT); - ioc = get_io_context(gfp_mask); + ioc = get_io_context(gfp_mask, cfqd->queue->node); if (!ioc) return NULL; @@ -1955,7 +1956,7 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) struct cfq_data *cfqd; int i; - cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL); + cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node); if (!cfqd) return NULL; @@ -1970,7 +1971,7 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) INIT_LIST_HEAD(&cfqd->empty_list); INIT_LIST_HEAD(&cfqd->cic_list); - cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL); + cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); if (!cfqd->cfq_hash) goto out_free; -- cgit v1.2.3 From 53b03744e5699832e6c5b04f2ec506d8b0c50c38 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Fri, 28 Jul 2006 09:48:51 +0200 Subject: [PATCH] cfq-iosched: Kill O(N) runtime of cfq_resort_rr_list() Currently it scales with number of processes in that priority group, which is potentially not very nice as it's called quite often. Basically we always need to do tail inserts, except for the case of a new process. So just mark/detect a queue as such. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 53 ++++++++++++++++++++++------------------------------- 1 file changed, 22 insertions(+), 31 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 0452108a932..c6e649f3cae 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -152,7 +152,6 @@ struct cfq_queue { unsigned long slice_start; unsigned long slice_end; unsigned long slice_left; - unsigned long service_last; /* number of requests that are on the dispatch list */ int on_dispatch[2]; @@ -174,6 +173,7 @@ enum cfqq_state_flags { 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) \ @@ -198,6 +198,7 @@ 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); @@ -350,7 +351,7 @@ cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq, static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) { struct cfq_data *cfqd = cfqq->cfqd; - struct list_head *list, *entry; + struct list_head *list; BUG_ON(!cfq_cfqq_on_rr(cfqq)); @@ -375,31 +376,26 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) } /* - * if queue was preempted, just add to front to be fair. busy_rr - * isn't sorted, but insert at the back for fairness. + * 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 || list == &cfqd->busy_rr) { - if (preempted) - list = list->prev; + if (preempted || cfq_cfqq_queue_new(cfqq)) { + struct list_head *n = list; + struct cfq_queue *__cfqq; - list_add_tail(&cfqq->cfq_list, list); - return; - } + while (n->next != list) { + __cfqq = list_entry_cfqq(n->next); + if (!cfq_cfqq_queue_new(__cfqq)) + break; - /* - * sort by when queue was last serviced - */ - entry = list; - while ((entry = entry->prev) != list) { - struct cfq_queue *__cfqq = list_entry_cfqq(entry); + n = n->next; + } - if (!__cfqq->service_last) - break; - if (time_before(__cfqq->service_last, cfqq->service_last)) - break; + list = n; } - list_add(&cfqq->cfq_list, entry); + list_add_tail(&cfqq->cfq_list, list); } /* @@ -591,13 +587,12 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfq_cfqq_wait_request(cfqq)) del_timer(&cfqd->idle_slice_timer); - if (!preempted && !cfq_cfqq_dispatched(cfqq)) { - cfqq->service_last = now; + 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 @@ -1297,13 +1292,13 @@ retry: hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]); atomic_set(&cfqq->ref, 0); cfqq->cfqd = cfqd; - cfqq->service_last = 0; /* * set ->slice_left to allow preemption for a new process */ cfqq->slice_left = 2 * cfqd->cfq_slice_idle; cfq_mark_cfqq_idle_window(cfqq); cfq_mark_cfqq_prio_changed(cfqq); + cfq_mark_cfqq_queue_new(cfqq); cfq_init_prio_data(cfqq); } @@ -1672,12 +1667,8 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq) if (!cfq_class_idle(cfqq)) cfqd->last_end_request = now; - if (!cfq_cfqq_dispatched(cfqq)) { - if (cfq_cfqq_on_rr(cfqq)) { - cfqq->service_last = now; - cfq_resort_rr_list(cfqq, 0); - } - } + if (!cfq_cfqq_dispatched(cfqq) && cfq_cfqq_on_rr(cfqq)) + cfq_resort_rr_list(cfqq, 0); if (sync) RQ_CIC(rq)->last_end_request = now; -- cgit v1.2.3 From 981a79730d586335ef8f942c83bdf2b1de6d4e3d Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 19 Jul 2006 14:56:28 +0200 Subject: [PATCH] cfq-iosched: kill the empty_list No point in having a place holder list just for empty queues, so remove it. It's not used for anything other than to keep ->cfq_list busy. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index c6e649f3cae..6fb1613d44d 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -81,11 +81,6 @@ struct cfq_data { struct list_head idle_rr; unsigned int busy_queues; - /* - * non-ordered list of empty cfqq's - */ - struct list_head empty_list; - /* * cfqq lookup hash */ @@ -136,7 +131,7 @@ struct cfq_queue { struct hlist_node cfq_hash; /* hash key */ unsigned int key; - /* on either rr or empty list of cfqd */ + /* member of the rr/busy/cur/idle cfqd list */ struct list_head cfq_list; /* sorted list of pending requests */ struct rb_root sort_list; @@ -417,7 +412,7 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) { BUG_ON(!cfq_cfqq_on_rr(cfqq)); cfq_clear_cfqq_on_rr(cfqq); - list_move(&cfqq->cfq_list, &cfqd->empty_list); + list_del_init(&cfqq->cfq_list); BUG_ON(!cfqd->busy_queues); cfqd->busy_queues--; @@ -1959,7 +1954,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) INIT_LIST_HEAD(&cfqd->busy_rr); INIT_LIST_HEAD(&cfqd->cur_rr); INIT_LIST_HEAD(&cfqd->idle_rr); - INIT_LIST_HEAD(&cfqd->empty_list); INIT_LIST_HEAD(&cfqd->cic_list); cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); -- cgit v1.2.3 From dc72ef4ae35c2016fb594bcc85ce871376682174 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 20 Jul 2006 14:54:05 +0200 Subject: [PATCH] Add blk_start_queueing() helper CFQ implements this on its own now, but it's really block layer knowledge. Tells a device queue to start dispatching requests to the driver, taking care to unplug if needed. Also fixes the issue where as/cfq will invoke a stopped queue, which we really don't want. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 22 ++++------------------ 1 file changed, 4 insertions(+), 18 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 6fb1613d44d..9f684cc66bd 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1552,19 +1552,6 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) __cfq_set_active_queue(cfqd, cfqq); } -/* - * should really be a ll_rw_blk.c helper - */ -static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq) -{ - request_queue_t *q = cfqd->queue; - - if (!blk_queue_plugged(q)) - q->request_fn(q); - else - __generic_unplug_device(q); -} - /* * Called when a new fs request (rq) is added (to cfqq). Check if there's * something we should do about it @@ -1593,7 +1580,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cic == cfqd->active_cic && del_timer(&cfqd->idle_slice_timer)) { cfq_slice_expired(cfqd, 0); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } return; } @@ -1614,7 +1601,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (cfq_cfqq_wait_request(cfqq)) { cfq_mark_cfqq_must_dispatch(cfqq); del_timer(&cfqd->idle_slice_timer); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } } else if (cfq_should_preempt(cfqd, cfqq, rq)) { /* @@ -1624,7 +1611,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, */ cfq_preempt_queue(cfqd, cfqq); cfq_mark_cfqq_must_dispatch(cfqq); - cfq_start_queueing(cfqd, cfqq); + blk_start_queueing(cfqd->queue); } } @@ -1832,8 +1819,7 @@ static void cfq_kick_queue(void *data) unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - blk_remove_plug(q); - q->request_fn(q); + blk_start_queueing(q); spin_unlock_irqrestore(q->queue_lock, flags); } -- cgit v1.2.3 From bf57225670bcbeb357182d800736b4782cde7295 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 19 Jul 2006 20:29:12 +0200 Subject: [PATCH] cfq-iosched: improve queue preemption Don't touch the current queues, just make sure that the wanted queue is selected next. Simplifies the logic. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 9f684cc66bd..14110483595 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1539,17 +1539,19 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, */ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) { - struct cfq_queue *__cfqq, *next; - - list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list) - cfq_resort_rr_list(__cfqq, 1); + 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; - cfq_slice_expired(cfqd, 1); - __cfq_set_active_queue(cfqd, cfqq); } /* -- cgit v1.2.3 From 374f84ac39ec7829a57a66efd5125d3561ff0e00 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 23 Jul 2006 01:42:19 +0200 Subject: [PATCH] cfq-iosched: use metadata read flag Give meta data reads preference over regular reads, as the process often needs to get that out of the way to do the io it was actually interested in. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 14110483595..6dbee46240c 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -141,6 +141,8 @@ struct cfq_queue { 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; @@ -248,6 +250,10 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *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; @@ -510,6 +516,11 @@ static void cfq_remove_request(struct request *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 @@ -1527,8 +1538,18 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, */ 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; } @@ -1564,6 +1585,9 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, { 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)) { */ -- cgit v1.2.3 From 0fe23479577124bd2687e6783e39fa0fa4c28005 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 4 Sep 2006 15:41:16 +0200 Subject: [PATCH] Update axboe@suse.de email address As people often look for the copyright in files to see who to mail, update the link to a neutral one. Signed-off-by: Jens Axboe --- block/cfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 6dbee46240c..99116e2a310 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -4,7 +4,7 @@ * Based on ideas from a previously unfinished io * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli. * - * Copyright (C) 2003 Jens Axboe + * Copyright (C) 2003 Jens Axboe */ #include #include -- cgit v1.2.3 From 6e9a4738c9fadb7cbdcabc1e3b415159f3741ed9 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 30 Sep 2006 23:28:10 -0700 Subject: [PATCH] completions: lockdep annotate on stack completions All on stack DECLARE_COMPLETIONs should be replaced by: DECLARE_COMPLETION_ONSTACK Signed-off-by: Peter Zijlstra Acked-by: Ingo Molnar Acked-by: Benjamin Herrenschmidt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- block/cfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/cfq-iosched.c') diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 99116e2a310..d3d76136f53 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2160,7 +2160,7 @@ static int __init cfq_init(void) static void __exit cfq_exit(void) { - DECLARE_COMPLETION(all_gone); + DECLARE_COMPLETION_ONSTACK(all_gone); elv_unregister(&iosched_cfq); ioc_gone = &all_gone; /* ioc_gone's update must be visible before reading ioc_count */ -- cgit v1.2.3