diff options
| -rw-r--r-- | Documentation/block/biodoc.txt | 113 | ||||
| -rw-r--r-- | drivers/block/as-iosched.c | 325 | ||||
| -rw-r--r-- | drivers/block/cfq-iosched.c | 364 | ||||
| -rw-r--r-- | drivers/block/deadline-iosched.c | 123 | ||||
| -rw-r--r-- | drivers/block/elevator.c | 266 | ||||
| -rw-r--r-- | drivers/block/ll_rw_blk.c | 23 | ||||
| -rw-r--r-- | drivers/block/noop-iosched.c | 48 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 26 | ||||
| -rw-r--r-- | include/linux/elevator.h | 18 |
9 files changed, 459 insertions, 847 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt index 6dd274d7e1cf..2d65c2182161 100644 --- a/Documentation/block/biodoc.txt +++ b/Documentation/block/biodoc.txt @@ -906,9 +906,20 @@ Aside: 4. The I/O scheduler -I/O schedulers are now per queue. They should be runtime switchable and modular -but aren't yet. Jens has most bits to do this, but the sysfs implementation is -missing. +I/O scheduler, a.k.a. elevator, is implemented in two layers. Generic dispatch +queue and specific I/O schedulers. Unless stated otherwise, elevator is used +to refer to both parts and I/O scheduler to specific I/O schedulers. + +Block layer implements generic dispatch queue in ll_rw_blk.c and elevator.c. +The generic dispatch queue is responsible for properly ordering barrier +requests, requeueing, handling non-fs requests and all other subtleties. + +Specific I/O schedulers are responsible for ordering normal filesystem +requests. They can also choose to delay certain requests to improve +throughput or whatever purpose. As the plural form indicates, there are +multiple I/O schedulers. They can be built as modules but at least one should +be built inside the kernel. Each queue can choose different one and can also +change to another one dynamically. A block layer call to the i/o scheduler follows the convention elv_xxx(). This calls elevator_xxx_fn in the elevator switch (drivers/block/elevator.c). Oh, @@ -921,44 +932,36 @@ keeping work. The functions an elevator may implement are: (* are mandatory) elevator_merge_fn called to query requests for merge with a bio -elevator_merge_req_fn " " " with another request +elevator_merge_req_fn called when two requests get merged. the one + which gets merged into the other one will be + never seen by I/O scheduler again. IOW, after + being merged, the request is gone. elevator_merged_fn called when a request in the scheduler has been involved in a merge. It is used in the deadline scheduler for example, to reposition the request if its sorting order has changed. -*elevator_next_req_fn returns the next scheduled request, or NULL - if there are none (or none are ready). +elevator_dispatch_fn fills the dispatch queue with ready requests. + I/O schedulers are free to postpone requests by + not filling the dispatch queue unless @force + is non-zero. Once dispatched, I/O schedulers + are not allowed to manipulate the requests - + they belong to generic dispatch queue. -*elevator_add_req_fn called to add a new request into the scheduler +elevator_add_req_fn called to add a new request into the scheduler elevator_queue_empty_fn returns true if the merge queue is empty. Drivers shouldn't use this, but rather check if elv_next_request is NULL (without losing the request if one exists!) -elevator_remove_req_fn This is called when a driver claims ownership of - the target request - it now belongs to the - driver. It must not be modified or merged. - Drivers must not lose the request! A subsequent - call of elevator_next_req_fn must return the - _next_ request. - -elevator_requeue_req_fn called to add a request to the scheduler. This - is used when the request has alrnadebeen - returned by elv_next_request, but hasn't - completed. If this is not implemented then - elevator_add_req_fn is called instead. - elevator_former_req_fn elevator_latter_req_fn These return the request before or after the one specified in disk sort order. Used by the block layer to find merge possibilities. -elevator_completed_req_fn called when a request is completed. This might - come about due to being merged with another or - when the device completes the request. +elevator_completed_req_fn called when a request is completed. elevator_may_queue_fn returns true if the scheduler wants to allow the current context to queue a new request even if @@ -967,13 +970,33 @@ elevator_may_queue_fn returns true if the scheduler wants to allow the elevator_set_req_fn elevator_put_req_fn Must be used to allocate and free any elevator - specific storate for a request. + specific storage for a request. + +elevator_activate_req_fn Called when device driver first sees a request. + I/O schedulers can use this callback to + determine when actual execution of a request + starts. +elevator_deactivate_req_fn Called when device driver decides to delay + a request by requeueing it. elevator_init_fn elevator_exit_fn Allocate and free any elevator specific storage for a queue. -4.2 I/O scheduler implementation +4.2 Request flows seen by I/O schedulers +All requests seens by I/O schedulers strictly follow one of the following three +flows. + + set_req_fn -> + + i. add_req_fn -> (merged_fn ->)* -> dispatch_fn -> activate_req_fn -> + (deactivate_req_fn -> activate_req_fn ->)* -> completed_req_fn + ii. add_req_fn -> (merged_fn ->)* -> merge_req_fn + iii. [none] + + -> put_req_fn + +4.3 I/O scheduler implementation The generic i/o scheduler algorithm attempts to sort/merge/batch requests for optimal disk scan and request servicing performance (based on generic principles and device capabilities), optimized for: @@ -993,18 +1016,7 @@ request in sort order to prevent binary tree lookups. This arrangement is not a generic block layer characteristic however, so elevators may implement queues as they please. -ii. Last merge hint -The last merge hint is part of the generic queue layer. I/O schedulers must do -some management on it. For the most part, the most important thing is to make -sure q->last_merge is cleared (set to NULL) when the request on it is no longer -a candidate for merging (for example if it has been sent to the driver). - -The last merge performed is cached as a hint for the subsequent request. If -sequential data is being submitted, the hint is used to perform merges without -any scanning. This is not sufficient when there are multiple processes doing -I/O though, so a "merge hash" is used by some schedulers. - -iii. Merge hash +ii. Merge hash AS and deadline use a hash table indexed by the last sector of a request. This enables merging code to quickly look up "back merge" candidates, even when multiple I/O streams are being performed at once on one disk. @@ -1013,29 +1025,8 @@ multiple I/O streams are being performed at once on one disk. are far less common than "back merges" due to the nature of most I/O patterns. Front merges are handled by the binary trees in AS and deadline schedulers. -iv. Handling barrier cases -A request with flags REQ_HARDBARRIER or REQ_SOFTBARRIER must not be ordered -around. That is, they must be processed after all older requests, and before -any newer ones. This includes merges! - -In AS and deadline schedulers, barriers have the effect of flushing the reorder -queue. The performance cost of this will vary from nothing to a lot depending -on i/o patterns and device characteristics. Obviously they won't improve -performance, so their use should be kept to a minimum. - -v. Handling insertion position directives -A request may be inserted with a position directive. The directives are one of -ELEVATOR_INSERT_BACK, ELEVATOR_INSERT_FRONT, ELEVATOR_INSERT_SORT. - -ELEVATOR_INSERT_SORT is a general directive for non-barrier requests. -ELEVATOR_INSERT_BACK is used to insert a barrier to the back of the queue. -ELEVATOR_INSERT_FRONT is used to insert a barrier to the front of the queue, and -overrides the ordering requested by any previous barriers. In practice this is -harmless and required, because it is used for SCSI requeueing. This does not -require flushing the reorder queue, so does not impose a performance penalty. - -vi. Plugging the queue to batch requests in anticipation of opportunities for - merge/sort optimizations +iii. Plugging the queue to batch requests in anticipation of opportunities for + merge/sort optimizations This is just the same as in 2.4 so far, though per-device unplugging support is anticipated for 2.5. Also with a priority-based i/o scheduler, @@ -1069,7 +1060,7 @@ Aside: blk_kick_queue() to unplug a specific queue (right away ?) or optionally, all queues, is in the plan. -4.3 I/O contexts +4.4 I/O contexts I/O contexts provide a dynamically allocated per process data area. They may be used in I/O schedulers, and in the block layer (could be used for IO statis, priorities for example). See *io_context in drivers/block/ll_rw_blk.c, and diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c index 1f08e14697e9..4081c36c8c19 100644 --- a/drivers/block/as-iosched.c +++ b/drivers/block/as-iosched.c @@ -98,7 +98,6 @@ struct as_data { struct as_rq *next_arq[2]; /* next in sort order */ sector_t last_sector[2]; /* last REQ_SYNC & REQ_ASYNC sectors */ - struct list_head *dispatch; /* driver dispatch queue */ struct list_head *hash; /* request hash */ unsigned long exit_prob; /* probability a task will exit while @@ -239,6 +238,25 @@ static struct io_context *as_get_io_context(void) return ioc; } +static void as_put_io_context(struct as_rq *arq) +{ + struct as_io_context *aic; + + if (unlikely(!arq->io_context)) + return; + + aic = arq->io_context->aic; + + if (arq->is_sync == REQ_SYNC && aic) { + spin_lock(&aic->lock); + set_bit(AS_TASK_IORUNNING, &aic->state); + aic->last_end_request = jiffies; + spin_unlock(&aic->lock); + } + + put_io_context(arq->io_context); +} + /* * the back merge hash support functions */ @@ -261,14 +279,6 @@ static inline void as_del_arq_hash(struct as_rq *arq) __as_del_arq_hash(arq); } -static void as_remove_merge_hints(request_queue_t *q, struct as_rq *arq) -{ - as_del_arq_hash(arq); - - if (q->last_merge == arq->request) - q->last_merge = NULL; -} - static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq) { struct request *rq = arq->request; @@ -312,7 +322,7 @@ static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset) BUG_ON(!arq->on_hash); if (!rq_mergeable(__rq)) { - as_remove_merge_hints(ad->q, arq); + as_del_arq_hash(arq); continue; } @@ -950,23 +960,12 @@ static void as_completed_request(request_queue_t *q, struct request *rq) WARN_ON(!list_empty(&rq->queuelist)); - if (arq->state == AS_RQ_PRESCHED) { - WARN_ON(arq->io_context); - goto out; - } - - if (arq->state == AS_RQ_MERGED) - goto out_ioc; - if (arq->state != AS_RQ_REMOVED) { printk("arq->state %d\n", arq->state); WARN_ON(1); goto out; } - if (!blk_fs_request(rq)) - goto out; - if (ad->changed_batch && ad->nr_dispatched == 1) { kblockd_schedule_work(&ad->antic_work); ad->changed_batch = 0; @@ -1001,21 +1000,7 @@ static void as_completed_request(request_queue_t *q, struct request *rq) } } -out_ioc: - if (!arq->io_context) - goto out; - - if (arq->is_sync == REQ_SYNC) { - struct as_io_context *aic = arq->io_context->aic; - if (aic) { - spin_lock(&aic->lock); - set_bit(AS_TASK_IORUNNING, &aic->state); - aic->last_end_request = jiffies; - spin_unlock(&aic->lock); - } - } - - put_io_context(arq->io_context); + as_put_io_context(arq); out: arq->state = AS_RQ_POSTSCHED; } @@ -1047,73 +1032,11 @@ static void as_remove_queued_request(request_queue_t *q, struct request *rq) ad->next_arq[data_dir] = as_find_next_arq(ad, arq); list_del_init(&arq->fifo); - as_remove_merge_hints(q, arq); + as_del_arq_hash(arq); as_del_arq_rb(ad, arq); } /* - * as_remove_dispatched_request is called to remove a request which has gone - * to the dispatch list. - */ -static void as_remove_dispatched_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - struct as_io_context *aic; - - if (!arq) { - WARN_ON(1); - return; - } - - WARN_ON(arq->state != AS_RQ_DISPATCHED); - WARN_ON(ON_RB(&arq->rb_node)); - if (arq->io_context && arq->io_context->aic) { - aic = arq->io_context->aic; - if (aic) { - WARN_ON(!atomic_read(&aic->nr_dispatched)); - atomic_dec(&aic->nr_dispatched); - } - } -} - -/* - * as_remove_request is called when a driver has finished with a request. - * This should be only called for dispatched requests, but for some reason - * a POWER4 box running hwscan it does not. - */ -static void as_remove_request(request_queue_t *q, struct request *rq) -{ - struct as_rq *arq = RQ_DATA(rq); - - if (unlikely(arq->state == AS_RQ_NEW)) - goto out; - - if (ON_RB(&arq->rb_node)) { - if (arq->state != AS_RQ_QUEUED) { - printk("arq->state %d\n", arq->state); - WARN_ON(1); - goto out; - } - /* - * We'll lose the aliased request(s) here. I don't think this - * will ever happen, but if it does, hopefully someone will - * report it. - */ - WARN_ON(!list_empty(&rq->queuelist)); - as_remove_queued_request(q, rq); - } else { - if (arq->state != AS_RQ_DISPATCHED) { - printk("arq->state %d\n", arq->state); - WARN_ON(1); - goto out; - } - as_remove_dispatched_request(q, rq); - } -out: - arq->state = AS_RQ_REMOVED; -} - -/* * as_fifo_expired returns 0 if there are no expired reads on the fifo, * 1 otherwise. It is ratelimited so that we only perform the check once per * `fifo_expire' interval. Otherwise a large number of expired requests @@ -1165,7 +1088,6 @@ static inline int as_batch_expired(struct as_data *ad) static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq) { struct request *rq = arq->request; - struct list_head *insert; const int data_dir = arq->is_sync; BUG_ON(!ON_RB(&arq->rb_node)); @@ -1198,13 +1120,13 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq) /* * take it off the sort and fifo list, add to dispatch queue */ - insert = ad->dispatch->prev; - while (!list_empty(&rq->queuelist)) { struct request *__rq = list_entry_rq(rq->queuelist.next); struct as_rq *__arq = RQ_DATA(__rq); - list_move_tail(&__rq->queuelist, ad->dispatch); + list_del(&__rq->queuelist); + + elv_dispatch_add_tail(ad->q, __rq); if (__arq->io_context && __arq->io_context->aic) atomic_inc(&__arq->io_context->aic->nr_dispatched); @@ -1218,7 +1140,8 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq) as_remove_queued_request(ad->q, rq); WARN_ON(arq->state != AS_RQ_QUEUED); - list_add(&rq->queuelist, insert); + elv_dispatch_sort(ad->q, rq); + arq->state = AS_RQ_DISPATCHED; if (arq->io_context && arq->io_context->aic) atomic_inc(&arq->io_context->aic->nr_dispatched); @@ -1230,12 +1153,42 @@ static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq) * read/write expire, batch expire, etc, and moves it to the dispatch * queue. Returns 1 if a request was found, 0 otherwise. */ -static int as_dispatch_request(struct as_data *ad) +static int as_dispatch_request(request_queue_t *q, int force) { + struct as_data *ad = q->elevator->elevator_data; struct as_rq *arq; const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]); const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]); + if (unlikely(force)) { + /* + * Forced dispatch, accounting is useless. Reset + * accounting states and dump fifo_lists. Note that + * batch_data_dir is reset to REQ_SYNC to avoid + * screwing write batch accounting as write batch + * accounting occurs on W->R transition. + */ + int dispatched = 0; + + ad->batch_data_dir = REQ_SYNC; + ad->changed_batch = 0; + ad->new_batch = 0; + + while (ad->next_arq[REQ_SYNC]) { + as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]); + dispatched++; + } + ad->last_check_fifo[REQ_SYNC] = jiffies; + + while (ad->next_arq[REQ_ASYNC]) { + as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]); + dispatched++; + } + ad->last_check_fifo[REQ_ASYNC] = jiffies; + + return dispatched; + } + /* Signal that the write batch was uncontended, so we can't time it */ if (ad->batch_data_dir == REQ_ASYNC && !reads) { if (ad->current_write_count == 0 || !writes) @@ -1359,20 +1312,6 @@ fifo_expired: return 1; } -static struct request *as_next_request(request_queue_t *q) -{ - struct as_data *ad = q->elevator->elevator_data; - struct request *rq = NULL; - - /* - * if there are still requests on the dispatch queue, grab the first - */ - if (!list_empty(ad->dispatch) || as_dispatch_request(ad)) - rq = list_entry_rq(ad->dispatch->next); - - return rq; -} - /* * Add arq to a list behind alias */ @@ -1404,17 +1343,25 @@ as_add_aliased_request(struct as_data *ad, struct as_rq *arq, struct as_rq *alia /* * Don't want to have to handle merges. */ - as_remove_merge_hints(ad->q, arq); + as_del_arq_hash(arq); } /* * add arq to rbtree and fifo */ -static void as_add_request(struct as_data *ad, struct as_rq *arq) +static void as_add_request(request_queue_t *q, struct request *rq) { + struct as_data *ad = q->elevator->elevator_data; + struct as_rq *arq = RQ_DATA(rq); struct as_rq *alias; int data_dir; + if (arq->state != AS_RQ_PRESCHED) { + printk("arq->state: %d\n", arq->state); + WARN_ON(1); + } + arq->state = AS_RQ_NEW; + if (rq_data_dir(arq->request) == READ || current->flags&PF_SYNCWRITE) arq->is_sync = 1; @@ -1437,12 +1384,8 @@ static void as_add_request(struct as_data *ad, struct as_rq *arq) arq->expires = jiffies + ad->fifo_expire[data_dir]; list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]); - if (rq_mergeable(arq->request)) { + if (rq_mergeable(arq->request)) as_add_arq_hash(ad, arq); - - if (!ad->q->last_merge) - ad->q->last_merge = arq->request; - } as_update_arq(ad, arq); /* keep state machine up to date */ } else { @@ -1463,96 +1406,24 @@ static void as_add_request(struct as_data *ad, struct as_rq *arq) arq->state = AS_RQ_QUEUED; } -static void as_deactivate_request(request_queue_t *q, struct request *rq) +static void as_activate_request(request_queue_t *q, struct request *rq) { - struct as_data *ad = q->elevator->elevator_data; struct as_rq *arq = RQ_DATA(rq); - if (arq) { - if (arq->state == AS_RQ_REMOVED) { - arq->state = AS_RQ_DISPATCHED; - if (arq->io_context && arq->io_context->aic) - atomic_inc(&arq->io_context->aic->nr_dispatched); - } - } else - WARN_ON(blk_fs_request(rq) - && (!(rq->flags & (REQ_HARDBARRIER|REQ_SOFTBARRIER))) ); - - /* Stop anticipating - let this request get through */ - as_antic_stop(ad); -} - -/* - * requeue the request. The request has not been completed, nor is it a - * new request, so don't touch accounting. - */ -static void as_requeue_request(request_queue_t *q, struct request *rq) -{ - as_deactivate_request(q, rq); - list_add(&rq->queuelist, &q->queue_head); -} - -/* - * Account a request that is inserted directly onto the dispatch queue. - * arq->io_context->aic->nr_dispatched should not need to be incremented - * because only new requests should come through here: requeues go through - * our explicit requeue handler. - */ -static void as_account_queued_request(struct as_data *ad, struct request *rq) -{ - if (blk_fs_request(rq)) { - struct as_rq *arq = RQ_DATA(rq); - arq->state = AS_RQ_DISPATCHED; - ad->nr_dispatched++; - } + WARN_ON(arq->state != AS_RQ_DISPATCHED); + arq->state = AS_RQ_REMOVED; + if (arq->io_context && arq->io_context->aic) + atomic_dec(&arq->io_context->aic->nr_dispatched); } -static void -as_insert_request(request_queue_t *q, struct request *rq, int where) +static void as_deactivate_request(request_queue_t *q, struct request *rq) { - struct as_data *ad = q->elevator->elevator_data; struct as_rq *arq = RQ_DATA(rq); - if (arq) { - if (arq->state != AS_RQ_PRESCHED) { - printk("arq->state: %d\n", arq->state); - WARN_ON(1); - } - arq->state = AS_RQ_NEW; - } - - /* barriers must flush the reorder queue */ - if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER) - && where == ELEVATOR_INSERT_SORT)) { - WARN_ON(1); - where = ELEVATOR_INSERT_BACK; - } - - switch (where) { - case ELEVATOR_INSERT_BACK: - while (ad->next_arq[REQ_SYNC]) - as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]); - - while (ad->next_arq[REQ_ASYNC]) - as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]); - - list_add_tail(&rq->queuelist, ad->dispatch); - as_account_queued_request(ad, rq); - as_antic_stop(ad); - break; - case ELEVATOR_INSERT_FRONT: - list_add(&rq->queuelist, ad->dispatch); - as_account_queued_request(ad, rq); - as_antic_stop(ad); - break; - case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq)); - as_add_request(ad, arq); - break; - default: - BUG(); - return; - } + WARN_ON(arq->state != AS_RQ_REMOVED); + arq->state = AS_RQ_DISPATCHED; + if (arq->io_context && arq->io_context->aic) + atomic_inc(&arq->io_context->aic->nr_dispatched); } /* @@ -1565,12 +1436,8 @@ static int as_queue_empty(request_queue_t *q) { struct as_data *ad = q->elevator->elevator_data; - if (!list_empty(&ad->fifo_list[REQ_ASYNC]) - || !list_empty(&ad->fifo_list[REQ_SYNC]) - || !list_empty(ad->dispatch)) - return 0; - - return 1; + return list_empty(&ad->fifo_list[REQ_ASYNC]) + && list_empty(&ad->fifo_list[REQ_SYNC]); } static struct request * @@ -1608,15 +1475,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio) int ret; /* - * try last_merge to avoid going to hash - */ - ret = elv_try_last_merge(q, bio); - if (ret != ELEVATOR_NO_MERGE) { - __rq = q->last_merge; - goto out_insert; - } - - /* * see if the merge hash can satisfy a back merge */ __rq = as_find_arq_hash(ad, bio->bi_sector); @@ -1644,9 +1502,6 @@ as_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; out: - if (rq_mergeable(__rq)) - q->last_merge = __rq; -out_insert: if (ret) { if (rq_mergeable(__rq)) as_hot_arq_hash(ad, RQ_DATA(__rq)); @@ -1693,9 +1548,6 @@ static void as_merged_request(request_queue_t *q, struct request *req) * behind the disk head. We currently don't bother adjusting. */ } - - if (arq->on_hash) - q->last_merge = req; } static void @@ -1763,6 +1615,7 @@ as_merged_requests(request_queue_t *q, struct request *req, * kill knowledge of next, this one is a goner */ as_remove_queued_request(q, next); + as_put_io_context(anext); anext->state = AS_RQ_MERGED; } @@ -1782,7 +1635,7 @@ static void as_work_handler(void *data) unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - if (as_next_request(q)) + if (!as_queue_empty(q)) q->request_fn(q); spin_unlock_irqrestore(q->queue_lock, flags); } @@ -1797,7 +1650,9 @@ static void as_put_request(request_queue_t *q, struct request *rq) return; } - if (arq->state != AS_RQ_POSTSCHED && arq->state != AS_RQ_PRESCHED) { + if (unlikely(arq->state != AS_RQ_POSTSCHED && + arq->state != AS_RQ_PRESCHED && + arq->state != AS_RQ_MERGED)) { printk("arq->state %d\n", arq->state); WARN_ON(1); } @@ -1907,7 +1762,6 @@ static int as_init_queue(request_queue_t *q, elevator_t *e) INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]); ad->sort_list[REQ_SYNC] = RB_ROOT; ad->sort_list[REQ_ASYNC] = RB_ROOT; - ad->dispatch = &q->queue_head; ad->fifo_expire[REQ_SYNC] = default_read_expire; ad->fifo_expire[REQ_ASYNC] = default_write_expire; ad->antic_expire = default_antic_expire; @@ -2072,10 +1926,9 @@ static struct elevator_type iosched_as = { .elevator_merge_fn = as_merge, .elevator_merged_fn = as_merged_request, .elevator_merge_req_fn = as_merged_requests, - .elevator_next_req_fn = as_next_request, - .elevator_add_req_fn = as_insert_request, - .elevator_remove_req_fn = as_remove_request, - .elevator_requeue_req_fn = as_requeue_request, + .elevator_dispatch_fn = as_dispatch_request, + .elevator_add_req_fn = as_add_request, + .elevator_activate_req_fn = as_activate_request, .elevator_deactivate_req_fn = as_deactivate_request, .elevator_queue_empty_fn = as_queue_empty, .elevator_completed_req_fn = as_completed_request, diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c index d3bfe8cfb039..94690e4d41e0 100644 --- a/drivers/block/cfq-iosched.c +++ b/drivers/block/cfq-iosched.c @@ -84,7 +84,6 @@ static int cfq_max_depth = 2; (node)->rb_left = NULL; \ } while (0) #define RB_CLEAR_ROOT(root) ((root)->rb_node = NULL) -#define ON_RB(node) ((node)->rb_color != RB_NONE) #define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node) #define rq_rb_key(rq) (rq)->sector @@ -271,10 +270,7 @@ CFQ_CFQQ_FNS(expired); #undef CFQ_CFQQ_FNS enum cfq_rq_state_flags { - CFQ_CRQ_FLAG_in_flight = 0, - CFQ_CRQ_FLAG_in_driver, - CFQ_CRQ_FLAG_is_sync, - CFQ_CRQ_FLAG_requeued, + CFQ_CRQ_FLAG_is_sync = 0, }; #define CFQ_CRQ_FNS(name) \ @@ -291,14 +287,11 @@ static inline int cfq_crq_##name(const struct cfq_rq *crq) \ return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \ } -CFQ_CRQ_FNS(in_flight); -CFQ_CRQ_FNS(in_driver); CFQ_CRQ_FNS(is_sync); -CFQ_CRQ_FNS(requeued); #undef CFQ_CRQ_FNS static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short); -static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *); +static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *); static void cfq_put_cfqd(struct cfq_data *cfqd); #define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE) @@ -311,14 +304,6 @@ static inline void cfq_del_crq_hash(struct cfq_rq *crq) hlist_del_init(&crq->hash); } -static void cfq_remove_merge_hints(request_queue_t *q, struct cfq_rq *crq) -{ - cfq_del_crq_hash(crq); - - if (q->last_merge == crq->request) - q->last_merge = NULL; -} - 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)); @@ -347,18 +332,13 @@ static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset) return NULL; } -static inline int cfq_pending_requests(struct cfq_data *cfqd) -{ - return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues; -} - /* * scheduler run of queue, if there are requests pending and no one in the * driver that will restart queueing */ static inline void cfq_schedule_dispatch(struct cfq_data *cfqd) { - if (!cfqd->rq_in_driver && cfq_pending_requests(cfqd)) + if (!cfqd->rq_in_driver && cfqd->busy_queues) kblockd_schedule_work(&cfqd->unplug_work); } @@ -366,7 +346,7 @@ static int cfq_queue_empty(request_queue_t *q) { struct cfq_data *cfqd = q->elevator->elevator_data; - return !cfq_pending_requests(cfqd); + return !cfqd->busy_queues; } /* @@ -386,11 +366,6 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2) if (crq2 == NULL) return crq1; - if (cfq_crq_requeued(crq1) && !cfq_crq_requeued(crq2)) - return crq1; - else if (cfq_crq_requeued(crq2) && !cfq_crq_requeued(crq1)) - return crq2; - if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2)) return crq1; else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1)) @@ -461,10 +436,7 @@ cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct cfq_rq *crq_next = NULL, *crq_prev = NULL; struct rb_node *rbnext, *rbprev; - rbnext = NULL; - if (ON_RB(&last->rb_node)) - rbnext = rb_next(&last->rb_node); - if (!rbnext) { + if (!(rbnext = rb_next(&last->rb_node))) { rbnext = rb_first(&cfqq->sort_list); if (rbnext == &last->rb_node) rbnext = NULL; @@ -545,13 +517,13 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) * the pending list according to last request service */ static inline void -cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue) +cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) { BUG_ON(cfq_cfqq_on_rr(cfqq)); cfq_mark_cfqq_on_rr(cfqq); cfqd->busy_queues++; - cfq_resort_rr_list(cfqq, requeue); + cfq_resort_rr_list(cfqq, 0); } static inline void @@ -571,22 +543,19 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) 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); - if (ON_RB(&crq->rb_node)) { - struct cfq_data *cfqd = cfqq->cfqd; - const int sync = cfq_crq_is_sync(crq); + BUG_ON(!cfqq->queued[sync]); + cfqq->queued[sync]--; - BUG_ON(!cfqq->queued[sync]); - cfqq->queued[sync]--; + cfq_update_next_crq(crq); - cfq_update_next_crq(crq); + rb_erase(&crq->rb_node, &cfqq->sort_list); + RB_CLEAR_COLOR(&crq->rb_node); - rb_erase(&crq->rb_node, &cfqq->sort_list); - RB_CLEAR_COLOR(&crq->rb_node); - - if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) - cfq_del_cfqq_rr(cfqd, cfqq); - } + if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list)) + cfq_del_cfqq_rr(cfqd, cfqq); } static struct cfq_rq * @@ -627,12 +596,12 @@ static void cfq_add_crq_rb(struct cfq_rq *crq) * if that happens, put the alias on the dispatch list */ while ((__alias = __cfq_add_crq_rb(crq)) != NULL) - cfq_dispatch_sort(cfqd->queue, __alias); + 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, cfq_crq_requeued(crq)); + cfq_add_cfqq_rr(cfqd, cfqq); /* * check if this request is a better next-serve candidate @@ -643,10 +612,8 @@ 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) { - if (ON_RB(&crq->rb_node)) { - rb_erase(&crq->rb_node, &cfqq->sort_list); - cfqq->queued[cfq_crq_is_sync(crq)]--; - } + rb_erase(&crq->rb_node, &cfqq->sort_list); + cfqq->queued[cfq_crq_is_sync(crq)]--; cfq_add_crq_rb(crq); } @@ -676,49 +643,28 @@ out: return NULL; } -static void cfq_deactivate_request(request_queue_t *q, struct request *rq) +static void cfq_activate_request(request_queue_t *q, struct request *rq) { struct cfq_data *cfqd = q->elevator->elevator_data; - struct cfq_rq *crq = RQ_DATA(rq); - - if (crq) { - struct cfq_queue *cfqq = crq->cfq_queue; - - if (cfq_crq_in_driver(crq)) { - cfq_clear_crq_in_driver(crq); - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; - } - if (cfq_crq_in_flight(crq)) { - const int sync = cfq_crq_is_sync(crq); - cfq_clear_crq_in_flight(crq); - WARN_ON(!cfqq->on_dispatch[sync]); - cfqq->on_dispatch[sync]--; - } - cfq_mark_crq_requeued(crq); - } + cfqd->rq_in_driver++; } -/* - * make sure the service time gets corrected on reissue of this request - */ -static void cfq_requeue_request(request_queue_t *q, struct request *rq) +static void cfq_deactivate_request(request_queue_t *q, struct request *rq) { - cfq_deactivate_request(q, rq); - list_add(&rq->queuelist, &q->queue_head); + struct cfq_data *cfqd = q->elevator->elevator_data; + + WARN_ON(!cfqd->rq_in_driver); + cfqd->rq_in_driver--; } -static void cfq_remove_request(request_queue_t *q, struct request *rq) +static void cfq_remove_request(struct request *rq) { struct cfq_rq *crq = RQ_DATA(rq); - if (crq) { - list_del_init(&rq->queuelist); - cfq_del_crq_rb(crq); - cfq_remove_merge_hints(q, crq); - - } + list_del_init(&rq->queuelist); + cfq_del_crq_rb(crq); + cfq_del_crq_hash(crq); } static int @@ -728,12 +674,6 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) struct request *__rq; int ret; - ret = elv_try_last_merge(q, bio); - if (ret != ELEVATOR_NO_MERGE) { - __rq = q->last_merge; - goto out_insert; - } - __rq = cfq_find_rq_hash(cfqd, bio->bi_sector); if (__rq && elv_rq_merge_ok(__rq, bio)) { ret = ELEVATOR_BACK_MERGE; @@ -748,8 +688,6 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; out: - q->last_merge = __rq; -out_insert: *req = __rq; return ret; } @@ -762,14 +700,12 @@ static void cfq_merged_request(request_queue_t *q, struct request *req) cfq_del_crq_hash(crq); cfq_add_crq_hash(cfqd, crq); - if (ON_RB(&crq->rb_node) && (rq_rb_key(req) != crq->rb_key)) { + if (rq_rb_key(req) != crq->rb_key) { struct cfq_queue *cfqq = crq->cfq_queue; cfq_update_next_crq(crq); cfq_reposition_crq_rb(cfqq, crq); } - - q->last_merge = req; } static void @@ -785,7 +721,7 @@ cfq_merged_requests(request_queue_t *q, struct request *rq, time_before(next->start_time, rq->start_time)) list_move(&rq->queuelist, &next->queuelist); - cfq_remove_request(q, next); + cfq_remove_request(next); } static inline void @@ -992,53 +928,15 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq) return 1; } -/* - * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues, - * this function sector sorts the selected request to minimize seeks. we start - * at cfqd->last_sector, not 0. - */ -static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq) +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 list_head *head = &q->queue_head, *entry = head; - struct request *__rq; - sector_t last; - - list_del(&crq->request->queuelist); - - last = cfqd->last_sector; - list_for_each_entry_reverse(__rq, head, queuelist) { - struct cfq_rq *__crq = RQ_DATA(__rq); - - if (blk_barrier_rq(__rq)) - break; - if (!blk_fs_request(__rq)) - break; - if (cfq_crq_requeued(__crq)) - break; - - if (__rq->sector <= crq->request->sector) - break; - if (__rq->sector > last && crq->request->sector < last) { - last = crq->request->sector + crq->request->nr_sectors; - break; - } - entry = &__rq->queuelist; - } - - cfqd->last_sector = last; cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq); - - cfq_del_crq_rb(crq); - cfq_remove_merge_hints(q, crq); - - cfq_mark_crq_in_flight(crq); - cfq_clear_crq_requeued(crq); - + cfq_remove_request(crq->request); cfqq->on_dispatch[cfq_crq_is_sync(crq)]++; - list_add_tail(&crq->request->queuelist, entry); + elv_dispatch_sort(q, crq->request); } /* @@ -1159,7 +1057,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, /* * finally, insert request into driver dispatch list */ - cfq_dispatch_sort(cfqd->queue, crq); + cfq_dispatch_insert(cfqd->queue, crq); cfqd->dispatch_slice++; dispatched++; @@ -1194,7 +1092,7 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq, } static int -cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force) +cfq_dispatch_requests(request_queue_t *q, int force) { struct cfq_data *cfqd = q->elevator->elevator_data; struct cfq_queue *cfqq; @@ -1204,12 +1102,25 @@ cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force) cfqq = cfq_select_queue(cfqd, force); if (cfqq) { + int max_dispatch; + + /* + * if idle window is disabled, allow queue buildup + */ + if (!cfq_cfqq_idle_window(cfqq) && + cfqd->rq_in_driver >= cfqd->cfq_max_depth) + return 0; + cfq_clear_cfqq_must_dispatch(cfqq); cfq_clear_cfqq_wait_request(cfqq); del_timer(&cfqd->idle_slice_timer); - if (cfq_class_idle(cfqq)) - max_dispatch = 1; + if (!force) { + max_dispatch = cfqd->cfq_quantum; + if (cfq_class_idle(cfqq)) + max_dispatch = 1; + } else + max_dispatch = INT_MAX; return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); } @@ -1217,93 +1128,6 @@ cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force) return 0; } -static inline void cfq_account_dispatch(struct cfq_rq *crq) -{ - struct cfq_queue *cfqq = crq->cfq_queue; - struct cfq_data *cfqd = cfqq->cfqd; - - if (unlikely(!blk_fs_request(crq->request))) - return; - - /* - * accounted bit is necessary since some drivers will call - * elv_next_request() many times for the same request (eg ide) - */ - if (cfq_crq_in_driver(crq)) - return; - - cfq_mark_crq_in_driver(crq); - cfqd->rq_in_driver++; -} - -static inline void -cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq) -{ - struct cfq_data *cfqd = cfqq->cfqd; - unsigned long now; - - if (!cfq_crq_in_driver(crq)) - return; - - now = jiffies; - - WARN_ON(!cfqd->rq_in_driver); - cfqd->rq_in_driver--; - - if (!cfq_class_idle(cfqq)) - cfqd->last_end_request = now; - - if (!cfq_cfqq_dispatched(cfqq)) { - if (cfq_cfqq_on_rr(cfqq)) { - cfqq->service_last = now; - cfq_resort_rr_list(cfqq, 0); - } - if (cfq_cfqq_expired(cfqq)) { - __cfq_slice_expired(cfqd, cfqq, 0); - cfq_schedule_dispatch(cfqd); - } - } - - if (cfq_crq_is_sync(crq)) - crq->io_context->last_end_request = now; -} - -static struct request *cfq_next_request(request_queue_t *q) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - struct request *rq; - - if (!list_empty(&q->queue_head)) { - struct cfq_rq *crq; -dispatch: - rq = list_entry_rq(q->queue_head.next); - - crq = RQ_DATA(rq); - if (crq) { - struct cfq_queue *cfqq = crq->cfq_queue; - - /* - * if idle window is disabled, allow queue buildup - */ - if (!cfq_crq_in_driver(crq) && - !cfq_cfqq_idle_window(cfqq) && - !blk_barrier_rq(rq) && - cfqd->rq_in_driver >= cfqd->cfq_max_depth) - return NULL; - - cfq_remove_merge_hints(q, crq); - cfq_account_dispatch(crq); - } - - return rq; - } - - if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0)) - goto dispatch; - - return NULL; -} - /* * 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. @@ -1816,8 +1640,9 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, } } -static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq) +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; @@ -1827,66 +1652,43 @@ static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq) list_add_tail(&rq->queuelist, &cfqq->fifo); - if (rq_mergeable(rq)) { + if (rq_mergeable(rq)) cfq_add_crq_hash(cfqd, crq); - if (!cfqd->queue->last_merge) - cfqd->queue->last_merge = rq; - } - cfq_crq_enqueued(cfqd, cfqq, crq); } -static void -cfq_insert_request(request_queue_t *q, struct request *rq, int where) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - switch (where) { - case ELEVATOR_INSERT_BACK: - while (cfq_dispatch_requests(q, INT_MAX, 1)) - ; - list_add_tail(&rq->queuelist, &q->queue_head); - /* - * If we were idling with pending requests on - * inactive cfqqs, force dispatching will - * remove the idle timer and the queue won't - * be kicked by __make_request() afterward. - * Kick it here. - */ - cfq_schedule_dispatch(cfqd); - break; - case ELEVATOR_INSERT_FRONT: - list_add(&rq->queuelist, &q->queue_head); - break; - case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq)); - cfq_enqueue(cfqd, rq); - break; - default: - printk("%s: bad insert point %d\n", __FUNCTION__,where); - return; - } -} - static void cfq_completed_request(request_queue_t *q, struct request *rq) { struct cfq_rq *crq = RQ_DATA(rq); - struct cfq_queue *cfqq; + struct cfq_queue *cfqq = crq->cfq_queue; + struct cfq_data *cfqd = cfqq->cfqd; + const int sync = cfq_crq_is_sync(crq); + unsigned long now; - if (unlikely(!blk_fs_request(rq))) - return; + now = jiffies; - cfqq = crq->cfq_queue; + WARN_ON(!cfqd->rq_in_driver); + WARN_ON(!cfqq->on_dispatch[sync]); + cfqd->rq_in_driver--; + cfqq->on_dispatch[sync]--; - if (cfq_crq_in_flight(crq)) { - const int sync = cfq_crq_is_sync(crq); + if (!cfq_class_idle(cfqq)) + cfqd->last_end_request = now; - WARN_ON(!cfqq->on_dispatch[sync]); - cfqq->on_dispatch[sync]--; + if (!cfq_cfqq_dispatched(cfqq)) { + if (cfq_cfqq_on_rr(cfqq)) { + cfqq->service_last = now; + cfq_resort_rr_list(cfqq, 0); + } + if (cfq_cfqq_expired(cfqq)) { + __cfq_slice_expired(cfqd, cfqq, 0); + cfq_schedule_dispatch(cfqd); + } } - cfq_account_completion(cfqq, crq); + if (cfq_crq_is_sync(crq)) + crq->io_context->last_end_request = now; } static struct request * @@ -2118,9 +1920,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, INIT_HLIST_NODE(&crq->hash); crq->cfq_queue = cfqq; crq->io_context = cic; - cfq_clear_crq_in_flight(crq); - cfq_clear_crq_in_driver(crq); - cfq_clear_crq_requeued(crq); if (rw == READ || process_sync(tsk)) cfq_mark_crq_is_sync(crq); @@ -2201,7 +2000,7 @@ static void cfq_idle_slice_timer(unsigned long data) * only expire and reinvoke request handler, if there are * other queues with pending requests */ - if (!cfq_pending_requests(cfqd)) { + if (!cfqd->busy_queues) { cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end); add_timer(&cfqd->idle_slice_timer); goto out_cont; @@ -2576,10 +2375,9 @@ static struct elevator_type iosched_cfq = { .elevator_merge_fn = cfq_merge, .elevator_merged_fn = cfq_merged_request, .elevator_merge_req_fn = cfq_merged_requests, - .elevator_next_req_fn = cfq_next_request, + .elevator_dispatch_fn = cfq_dispatch_requests, .elevator_add_req_fn = cfq_insert_request, - .elevator_remove_req_fn = cfq_remove_request, - .elevator_requeue_req_fn = cfq_requeue_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, diff --git a/drivers/block/deadline-iosched.c b/drivers/block/deadline-iosched.c index 753546ba2262..7929471d7df7 100644 --- a/drivers/block/deadline-iosched.c +++ b/drivers/block/deadline-iosched.c @@ -50,7 +50,6 @@ struct deadline_data { * next in sort order. read, write or both are NULL */ struct deadline_rq *next_drq[2]; - struct list_head *dispatch; /* driver dispatch queue */ struct list_head *hash; /* request hash */ unsigned int batching; /* number of sequential requests made */ sector_t last_sector; /* head position */ @@ -113,15 +112,6 @@ static inline void deadline_del_drq_hash(struct deadline_rq *drq) __deadline_del_drq_hash(drq); } -static void -deadline_remove_merge_hints(request_queue_t *q, struct deadline_rq *drq) -{ - deadline_del_drq_hash(drq); - - if (q->last_merge == drq->request) - q->last_merge = NULL; -} - static inline void deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq) { @@ -239,10 +229,9 @@ deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq) dd->next_drq[data_dir] = rb_entry_drq(rbnext); } - if (ON_RB(&drq->rb_node)) { - rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); - RB_CLEAR(&drq->rb_node); - } + BUG_ON(!ON_RB(&drq->rb_node)); + rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq)); + RB_CLEAR(&drq->rb_node); } static struct request * @@ -286,7 +275,7 @@ deadline_find_first_drq(struct deadline_data *dd, int data_dir) /* * add drq to rbtree and fifo */ -static inline void +static void deadline_add_request(struct request_queue *q, struct request *rq) { struct deadline_data *dd = q->elevator->elevator_data; @@ -301,12 +290,8 @@ deadline_add_request(struct request_queue *q, struct request *rq) drq->expires = jiffies + dd->fifo_expire[data_dir]; list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]); - if (rq_mergeable(rq)) { + if (rq_mergeable(rq)) deadline_add_drq_hash(dd, drq); - - if (!q->last_merge) - q->last_merge = rq; - } } /* @@ -315,14 +300,11 @@ deadline_add_request(struct request_queue *q, struct request *rq) static void deadline_remove_request(request_queue_t *q, struct request *rq) { struct deadline_rq *drq = RQ_DATA(rq); + struct deadline_data *dd = q->elevator->elevator_data; - if (drq) { - struct deadline_data *dd = q->elevator->elevator_data; - - list_del_init(&drq->fifo); - deadline_remove_merge_hints(q, drq); - deadline_del_drq_rb(dd, drq); - } + list_del_init(&drq->fifo); + deadline_del_drq_rb(dd, drq); + deadline_del_drq_hash(drq); } static int @@ -333,15 +315,6 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) int ret; /* - * try last_merge to avoid going to hash - */ - ret = elv_try_last_merge(q, bio); - if (ret != ELEVATOR_NO_MERGE) { - __rq = q->last_merge; - goto out_insert; - } - - /* * see if the merge hash can satisfy a back merge */ __rq = deadline_find_drq_hash(dd, bio->bi_sector); @@ -373,8 +346,6 @@ deadline_merge(request_queue_t *q, struct request **req, struct bio *bio) return ELEVATOR_NO_MERGE; out: - q->last_merge = __rq; -out_insert: if (ret) deadline_hot_drq_hash(dd, RQ_DATA(__rq)); *req = __rq; @@ -399,8 +370,6 @@ static void deadline_merged_request(request_queue_t *q, struct request *req) deadline_del_drq_rb(dd, drq); deadline_add_drq_rb(dd, drq); } - - q->last_merge = req; } static void @@ -452,7 +421,7 @@ deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq) request_queue_t *q = drq->request->q; deadline_remove_request(q, drq->request); - list_add_tail(&drq->request->queuelist, dd->dispatch); + elv_dispatch_add_tail(q, drq->request); } /* @@ -502,8 +471,9 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir) * deadline_dispatch_requests selects the best request according to * read/write expire, fifo_batch, etc */ -static int deadline_dispatch_requests(struct deadline_data *dd) +static int deadline_dispatch_requests(request_queue_t *q, int force) { + struct deadline_data *dd = q->elevator->elevator_data; const int reads = !list_empty(&dd->fifo_list[READ]); const int writes = !list_empty(&dd->fifo_list[WRITE]); struct deadline_rq *drq; @@ -597,65 +567,12 @@ dispatch_request: return 1; } -static struct request *deadline_next_request(request_queue_t *q) -{ - struct deadline_data *dd = q->elevator->elevator_data; - struct request *rq; - - /* - * if there are still requests on the dispatch queue, grab the first one - */ - if (!list_empty(dd->dispatch)) { -dispatch: - rq = list_entry_rq(dd->dispatch->next); - return rq; - } - - if (deadline_dispatch_requests(dd)) - goto dispatch; - - return NULL; -} - -static void -deadline_insert_request(request_queue_t *q, struct request *rq, int where) -{ - struct deadline_data *dd = q->elevator->elevator_data; - - /* barriers must flush the reorder queue */ - if (unlikely(rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER) - && where == ELEVATOR_INSERT_SORT)) - where = ELEVATOR_INSERT_BACK; - - switch (where) { - case ELEVATOR_INSERT_BACK: - while (deadline_dispatch_requests(dd)) - ; - list_add_tail(&rq->queuelist, dd->dispatch); - break; - case ELEVATOR_INSERT_FRONT: - list_add(&rq->queuelist, dd->dispatch); - break; - case ELEVATOR_INSERT_SORT: - BUG_ON(!blk_fs_request(rq)); - deadline_add_request(q, rq); - break; - default: - printk("%s: bad insert point %d\n", __FUNCTION__,where); - return; - } -} - static int deadline_queue_empty(request_queue_t *q) { struct deadline_data *dd = q->elevator->elevator_data; - if (!list_empty(&dd->fifo_list[WRITE]) - || !list_empty(&dd->fifo_list[READ]) - || !list_empty(dd->dispatch)) - return 0; - - return 1; + return list_empty(&dd->fifo_list[WRITE]) + && list_empty(&dd->fifo_list[READ]); } static struct request * @@ -733,7 +650,6 @@ static int deadline_init_queue(request_queue_t *q, elevator_t *e) INIT_LIST_HEAD(&dd->fifo_list[WRITE]); dd->sort_list[READ] = RB_ROOT; dd->sort_list[WRITE] = RB_ROOT; - dd->dispatch = &q->queue_head; dd->fifo_expire[READ] = read_expire; dd->fifo_expire[WRITE] = write_expire; dd->writes_starved = writes_starved; @@ -748,10 +664,8 @@ static void deadline_put_request(request_queue_t *q, struct request *rq) struct deadline_data *dd = q->elevator->elevator_data; struct deadline_rq *drq = RQ_DATA(rq); - if (drq) { - mempool_free(drq, dd->drq_pool); - rq->elevator_private = NULL; - } + mempool_free(drq, dd->drq_pool); + rq->elevator_private = NULL; } static int @@ -917,9 +831,8 @@ static struct elevator_type iosched_deadline = { .elevator_merge_fn = deadline_merge, .elevator_merged_fn = deadline_merged_request, .elevator_merge_req_fn = deadline_merged_requests, - .elevator_next_req_fn = deadline_next_request, - .elevator_add_req_fn = deadline_insert_request, - .elevator_remove_req_fn = deadline_remove_request, + .elevator_dispatch_fn = deadline_dispatch_requests, + .elevator_add_req_fn = deadline_add_request, .elevator_queue_empty_fn = deadline_queue_empty, .elevator_former_req_fn = deadline_former_request, .elevator_latter_req_fn = deadline_latter_request, diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c index 4f69d222b183..3b8099ccedff 100644 --- a/drivers/block/elevator.c +++ b/drivers/block/elevator.c @@ -83,15 +83,6 @@ inline int elv_try_merge(struct request *__rq, struct bio *bio) } EXPORT_SYMBOL(elv_try_merge); -inline int elv_try_last_merge(request_queue_t *q, struct bio *bio) -{ - if (q->last_merge) - return elv_try_merge(q->last_merge, bio); - - return ELEVATOR_NO_MERGE; -} -EXPORT_SYMBOL(elv_try_last_merge); - static struct elevator_type *elevator_find(const char *name) { struct elevator_type *e = NULL; @@ -143,6 +134,8 @@ static int elevator_attach(request_queue_t *q, struct elevator_type *e, INIT_LIST_HEAD(&q->queue_head); q->last_merge = NULL; q->elevator = eq; + q->end_sector = 0; + q->boundary_rq = NULL; if (eq->ops->elevator_init_fn) ret = eq->ops->elevator_init_fn(q, eq); @@ -225,9 +218,52 @@ void elevator_exit(elevator_t *e) kfree(e); } +/* + * Insert rq into dispatch queue of q. Queue lock must be held on + * entry. If sort != 0, rq is sort-inserted; otherwise, rq will be + * appended to the dispatch queue. To be used by specific elevators. + */ +void elv_dispatch_sort(request_queue_t *q, struct request *rq) +{ + sector_t boundary; + struct list_head *entry; + + if (q->last_merge == rq) + q->last_merge = NULL; + + boundary = q->end_sector; + + list_for_each_prev(entry, &q->queue_head) { + struct request *pos = list_entry_rq(entry); + + if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED)) + break; + if (rq->sector >= boundary) { + if (pos->sector < boundary) + continue; + } else { + if (pos->sector >= boundary) + break; + } + if (rq->sector >= pos->sector) + break; + } + + list_add(&rq->queuelist, entry); +} + int elv_merge(request_queue_t *q, struct request **req, struct bio *bio) { elevator_t *e = q->elevator; + int ret; + + if (q->last_merge) { + ret = elv_try_merge(q->last_merge, bio); + if (ret != ELEVATOR_NO_MERGE) { + *req = q->last_merge; + return ret; + } + } if (e->ops->elevator_merge_fn) return e->ops->elevator_merge_fn(q, req, bio); @@ -241,6 +277,8 @@ void elv_merged_request(request_queue_t *q, struct request *rq) if (e->ops->elevator_merged_fn) e->ops->elevator_merged_fn(q, rq); + + q->last_merge = rq; } void elv_merge_requests(request_queue_t *q, struct request *rq, @@ -248,20 +286,13 @@ void elv_merge_requests(request_queue_t *q, struct request *rq, { elevator_t *e = q->elevator; - if (q->last_merge == next) - q->last_merge = NULL; - if (e->ops->elevator_merge_req_fn) e->ops->elevator_merge_req_fn(q, rq, next); + + q->last_merge = rq; } -/* - * For careful internal use by the block layer. Essentially the same as - * a requeue in that it tells the io scheduler that this request is not - * active in the driver or hardware anymore, but we don't want the request - * added back to the scheduler. Function is not exported. - */ -void elv_deactivate_request(request_queue_t *q, struct request *rq) +void elv_requeue_request(request_queue_t *q, struct request *rq) { elevator_t *e = q->elevator; @@ -269,19 +300,14 @@ void elv_deactivate_request(request_queue_t *q, struct request *rq) * it already went through dequeue, we need to decrement the * in_flight count again */ - if (blk_account_rq(rq)) + if (blk_account_rq(rq)) { q->in_flight--; + if (blk_sorted_rq(rq) && e->ops->elevator_deactivate_req_fn) + e->ops->elevator_deactivate_req_fn(q, rq); + } rq->flags &= ~REQ_STARTED; - if (e->ops->elevator_deactivate_req_fn) - e->ops->elevator_deactivate_req_fn(q, rq); -} - -void elv_requeue_request(request_queue_t *q, struct request *rq) -{ - elv_deactivate_request(q, rq); - /* * if this is the flush, requeue the original instead and drop the flush */ @@ -290,55 +316,91 @@ void elv_requeue_request(request_queue_t *q, struct request *rq) rq = rq->end_io_data; } - /* - * the request is prepped and may have some resources allocated. - * allowing unprepped requests to pass this one may cause resource - * deadlock. turn on softbarrier. - */ - rq->flags |= REQ_SOFTBARRIER; - - /* - * if iosched has an explicit requeue hook, then use that. otherwise - * just put the request at the front of the queue - */ - if (q->elevator->ops->elevator_requeue_req_fn) - q->elevator->ops->elevator_requeue_req_fn(q, rq); - else - __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); + __elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0); } void __elv_add_request(request_queue_t *q, struct request *rq, int where, int plug) { - /* - * barriers implicitly indicate back insertion - */ - if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER) && - where == ELEVATOR_INSERT_SORT) - where = ELEVATOR_INSERT_BACK; + if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) { + /* + * barriers implicitly indicate back insertion + */ + if (where == ELEVATOR_INSERT_SORT) + where = ELEVATOR_INSERT_BACK; + + /* + * this request is scheduling boundary, update end_sector + */ + if (blk_fs_request(rq)) { + q->end_sector = rq_end_sector(rq); + q->boundary_rq = rq; + } + } if (plug) blk_plug_device(q); rq->q = q; - if (!test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags)) { - q->elevator->ops->elevator_add_req_fn(q, rq, where); - - if (blk_queue_plugged(q)) { - int nrq = q->rq.count[READ] + q->rq.count[WRITE] - - q->in_flight; - - if (nrq >= q->unplug_thresh) - __generic_unplug_device(q); - } - } else + if (unlikely(test_bit(QUEUE_FLAG_DRAIN, &q->queue_flags))) { /* * if drain is set, store the request "locally". when the drain * is finished, the requests will be handed ordered to the io * scheduler */ list_add_tail(&rq->queuelist, &q->drain_list); + return; + } + + switch (where) { + case ELEVATOR_INSERT_FRONT: + rq->flags |= REQ_SOFTBARRIER; + + list_add(&rq->queuelist, &q->queue_head); + break; + + case ELEVATOR_INSERT_BACK: + rq->flags |= REQ_SOFTBARRIER; + + while (q->elevator->ops->elevator_dispatch_fn(q, 1)) + ; + list_add_tail(&rq->queuelist, &q->queue_head); + /* + * We kick the queue here for the following reasons. + * - The elevator might have returned NULL previously + * to delay requests and returned them now. As the + * queue wasn't empty before this request, ll_rw_blk + * won't run the queue on return, resulting in hang. + * - Usually, back inserted requests won't be merged + * with anything. There's no point in delaying queue + * processing. + */ + blk_remove_plug(q); + q->request_fn(q); + break; + + case ELEVATOR_INSERT_SORT: + BUG_ON(!blk_fs_request(rq)); + rq->flags |= REQ_SORTED; + q->elevator->ops->elevator_add_req_fn(q, rq); + if (q->last_merge == NULL && rq_mergeable(rq)) + q->last_merge = rq; + break; + + default: + printk(KERN_ERR "%s: bad insertion point %d\n", + __FUNCTION__, where); + BUG(); + } + + if (blk_queue_plugged(q)) { + int nrq = q->rq.count[READ] + q->rq.count[WRITE] + - q->in_flight; + + if (nrq >= q->unplug_thresh) + __generic_unplug_device(q); + } } void elv_add_request(request_queue_t *q, struct request *rq, int where, @@ -353,13 +415,19 @@ void elv_add_request(request_queue_t *q, struct request *rq, int where, static inline struct request *__elv_next_request(request_queue_t *q) { - struct request *rq = q->elevator->ops->elevator_next_req_fn(q); + struct request *rq; + + if (unlikely(list_empty(&q->queue_head) && + !q->elevator->ops->elevator_dispatch_fn(q, 0))) + return NULL; + + rq = list_entry_rq(q->queue_head.next); /* * if this is a barrier write and the device has to issue a * flush sequence to support it, check how far we are */ - if (rq && blk_fs_request(rq) && blk_barrier_rq(rq)) { + if (blk_fs_request(rq) && blk_barrier_rq(rq)) { BUG_ON(q->ordered == QUEUE_ORDERED_NONE); if (q->ordered == QUEUE_ORDERED_FLUSH && @@ -376,15 +444,30 @@ struct request *elv_next_request(request_queue_t *q) int ret; while ((rq = __elv_next_request(q)) != NULL) { - /* - * just mark as started even if we don't start it, a request - * that has been delayed should not be passed by new incoming - * requests - */ - rq->flags |= REQ_STARTED; + if (!(rq->flags & REQ_STARTED)) { + elevator_t *e = q->elevator; + + /* + * This is the first time the device driver + * sees this request (possibly after + * requeueing). Notify IO scheduler. + */ + if (blk_sorted_rq(rq) && + e->ops->elevator_activate_req_fn) + e->ops->elevator_activate_req_fn(q, rq); - if (rq == q->last_merge) - q->last_merge = NULL; + /* + * just mark as started even if we don't start + * it, a request that has been delayed should + * not be passed by new incoming requests + */ + rq->flags |= REQ_STARTED; + } + + if (!q->boundary_rq || q->boundary_rq == rq) { + q->end_sector = rq_end_sector(rq); + q->boundary_rq = NULL; + } if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn) break; @@ -396,9 +479,9 @@ struct request *elv_next_request(request_queue_t *q) /* * the request may have been (partially) prepped. * we need to keep this request in the front to - * avoid resource deadlock. turn on softbarrier. + * avoid resource deadlock. REQ_STARTED will + * prevent other fs requests from passing this one. */ - rq->flags |= REQ_SOFTBARRIER; rq = NULL; break; } else if (ret == BLKPREP_KILL) { @@ -421,42 +504,32 @@ struct request *elv_next_request(request_queue_t *q) return rq; } -void elv_remove_request(request_queue_t *q, struct request *rq) +void elv_dequeue_request(request_queue_t *q, struct request *rq) { - elevator_t *e = q->elevator; + BUG_ON(list_empty(&rq->queuelist)); + + list_del_init(&rq->queuelist); /* * the time frame between a request being removed from the lists * and to it is freed is accounted as io that is in progress at - * the driver side. note that we only account requests that the - * driver has seen (REQ_STARTED set), to avoid false accounting - * for request-request merges + * the driver side. */ if (blk_account_rq(rq)) q->in_flight++; - - /* - * the main clearing point for q->last_merge is on retrieval of - * request by driver (it calls elv_next_request()), but it _can_ - * also happen here if a request is added to the queue but later - * deleted without ever being given to driver (merged with another - * request). - */ - if (rq == q->last_merge) - q->last_merge = NULL; - - if (e->ops->elevator_remove_req_fn) - e->ops->elevator_remove_req_fn(q, rq); } int elv_queue_empty(request_queue_t *q) { elevator_t *e = q->elevator; + if (!list_empty(&q->queue_head)) + return 0; + if (e->ops->elevator_queue_empty_fn) return e->ops->elevator_queue_empty_fn(q); - return list_empty(&q->queue_head); + return 1; } struct request *elv_latter_request(request_queue_t *q, struct request *rq) @@ -528,11 +601,11 @@ void elv_completed_request(request_queue_t *q, struct request *rq) /* * request is released from the driver, io must be done */ - if (blk_account_rq(rq)) + if (blk_account_rq(rq)) { q->in_flight--; - - if (e->ops->elevator_completed_req_fn) - e->ops->elevator_completed_req_fn(q, rq); + if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn) + e->ops->elevator_completed_req_fn(q, rq); + } } int elv_register_queue(struct request_queue *q) @@ -705,11 +778,12 @@ ssize_t elv_iosched_show(request_queue_t *q, char *name) return len; } +EXPORT_SYMBOL(elv_dispatch_sort); EXPORT_SYMBOL(elv_add_request); EXPORT_SYMBOL(__elv_add_request); EXPORT_SYMBOL(elv_requeue_request); EXPORT_SYMBOL(elv_next_request); -EXPORT_SYMBOL(elv_remove_request); +EXPORT_SYMBOL(elv_dequeue_request); EXPORT_SYMBOL(elv_queue_empty); EXPORT_SYMBOL(elv_completed_request); EXPORT_SYMBOL(elevator_exit); diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c index ac31ea170058..c4f186223bc5 100644 --- a/drivers/block/ll_rw_blk.c +++ b/drivers/block/ll_rw_blk.c @@ -353,6 +353,8 @@ static void blk_pre_flush_end_io(struct request *flush_rq) struct request *rq = flush_rq->end_io_data; request_queue_t *q = rq->q; + elv_completed_request(q, flush_rq); + rq->flags |= REQ_BAR_PREFLUSH; if (!flush_rq->errors) @@ -369,6 +371,8 @@ static void blk_post_flush_end_io(struct request *flush_rq) struct request *rq = flush_rq->end_io_data; request_queue_t *q = rq->q; + elv_completed_request(q, flush_rq); + rq->flags |= REQ_BAR_POSTFLUSH; q->end_flush_fn(q, flush_rq); @@ -408,8 +412,6 @@ struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq) if (!list_empty(&rq->queuelist)) blkdev_dequeue_request(rq); - elv_deactivate_request(q, rq); - flush_rq->end_io_data = rq; flush_rq->end_io = blk_pre_flush_end_io; @@ -1040,6 +1042,7 @@ EXPORT_SYMBOL(blk_queue_invalidate_tags); static char *rq_flags[] = { "REQ_RW", "REQ_FAILFAST", + "REQ_SORTED", "REQ_SOFTBARRIER", "REQ_HARDBARRIER", "REQ_CMD", @@ -2456,6 +2459,8 @@ static void __blk_put_request(request_queue_t *q, struct request *req) if (unlikely(--req->ref_count)) return; + elv_completed_request(q, req); + req->rq_status = RQ_INACTIVE; req->rl = NULL; @@ -2466,8 +2471,6 @@ static void __blk_put_request(request_queue_t *q, struct request *req) if (rl) { int rw = rq_data_dir(req); - elv_completed_request(q, req); - BUG_ON(!list_empty(&req->queuelist)); blk_free_request(q, req); @@ -2477,14 +2480,14 @@ static void __blk_put_request(request_queue_t *q, struct request *req) void blk_put_request(struct request *req) { + unsigned long flags; + request_queue_t *q = req->q; + /* - * if req->rl isn't set, this request didnt originate from the - * block layer, so it's safe to just disregard it + * Gee, IDE calls in w/ NULL q. Fix IDE and remove the + * following if (q) test. */ - if (req->rl) { - unsigned long flags; - request_queue_t *q = req->q; - + if (q) { spin_lock_irqsave(q->queue_lock, flags); __blk_put_request(q, req); spin_unlock_irqrestore(q->queue_lock, flags); diff --git a/drivers/block/noop-iosched.c b/drivers/block/noop-iosched.c index b1730b62c37e..f56b8edb06e4 100644 --- a/drivers/block/noop-iosched.c +++ b/drivers/block/noop-iosched.c @@ -7,57 +7,19 @@ #include <linux/module.h> #include <linux/init.h> -/* - * See if we can find a request that this buffer can be coalesced with. - */ -static int elevator_noop_merge(request_queue_t *q, struct request **req, - struct bio *bio) -{ - int ret; - - ret = elv_try_last_merge(q, bio); - if (ret != ELEVATOR_NO_MERGE) - *req = q->last_merge; - - return ret; -} - -static void elevator_noop_merge_requests(request_queue_t *q, struct request *req, - struct request *next) -{ - list_del_init(&next->queuelist); -} - -static void elevator_noop_add_request(request_queue_t *q, struct request *rq, - int where) +static void elevator_noop_add_request(request_queue_t *q, struct request *rq) { - if (where == ELEVATOR_INSERT_FRONT) - list_add(&rq->queuelist, &q->queue_head); - else - list_add_tail(&rq->queuelist, &q->queue_head); - - /* - * new merges must not precede this barrier - */ - if (rq->flags & REQ_HARDBARRIER) - q->last_merge = NULL; - else if (!q->last_merge) - q->last_merge = rq; + elv_dispatch_add_tail(q, rq); } -static struct request *elevator_noop_next_request(request_queue_t *q) +static int elevator_noop_dispatch(request_queue_t *q, int force) { - if (!list_empty(&q->queue_head)) - return list_entry_rq(q->queue_head.next); - - return NULL; + return 0; } static struct elevator_type elevator_noop = { .ops = { - .elevator_merge_fn = elevator_noop_merge, - .elevator_merge_req_fn = elevator_noop_merge_requests, - .elevator_next_req_fn = elevator_noop_next_request, + .elevator_dispatch_fn = elevator_noop_dispatch, .elevator_add_req_fn = elevator_noop_add_request, }, .elevator_name = "noop", diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1afbdb2d752c..fffe163316aa 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -203,6 +203,7 @@ struct request { enum rq_flag_bits { __REQ_RW, /* not set, read. set, write */ __REQ_FAILFAST, /* no low level driver retries */ + __REQ_SORTED, /* elevator knows about this request */ __REQ_SOFTBARRIER, /* may not be passed by ioscheduler */ __REQ_HARDBARRIER, /* may not be passed by drive either */ __REQ_CMD, /* is a regular fs rw request */ @@ -235,6 +236,7 @@ enum rq_flag_bits { #define REQ_RW (1 << __REQ_RW) #define REQ_FAILFAST (1 << __REQ_FAILFAST) +#define REQ_SORTED (1 << __REQ_SORTED) #define REQ_SOFTBARRIER (1 << __REQ_SOFTBARRIER) #define REQ_HARDBARRIER (1 << __REQ_HARDBARRIER) #define REQ_CMD (1 << __REQ_CMD) @@ -333,6 +335,12 @@ struct request_queue end_flush_fn *end_flush_fn; /* + * Dispatch queue sorting + */ + sector_t end_sector; + struct request *boundary_rq; + + /* * Auto-unplugging state */ struct timer_list unplug_timer; @@ -454,6 +462,7 @@ enum { #define blk_pm_request(rq) \ ((rq)->flags & (REQ_PM_SUSPEND | REQ_PM_RESUME)) +#define blk_sorted_rq(rq) ((rq)->flags & REQ_SORTED) #define blk_barrier_rq(rq) ((rq)->flags & REQ_HARDBARRIER) #define blk_barrier_preflush(rq) ((rq)->flags & REQ_BAR_PREFLUSH) #define blk_barrier_postflush(rq) ((rq)->flags & REQ_BAR_POSTFLUSH) @@ -611,12 +620,21 @@ extern void end_request(struct request *req, int uptodate); static inline void blkdev_dequeue_request(struct request *req) { - BUG_ON(list_empty(&req->queuelist)); + elv_dequeue_request(req->q, req); +} - list_del_init(&req->queuelist); +/* + * This should be in elevator.h, but that requires pulling in rq and q + */ +static inline void elv_dispatch_add_tail(struct request_queue *q, + struct request *rq) +{ + if (q->last_merge == rq) + q->last_merge = NULL; - if (req->rl) - elv_remove_request(req->q, req); + q->end_sector = rq_end_sector(rq); + q->boundary_rq = rq; + list_add_tail(&rq->queuelist, &q->queue_head); } /* diff --git a/include/linux/elevator.h b/include/linux/elevator.h index ed93125c1db5..a74c27e460ba 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -8,18 +8,17 @@ typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struc typedef void (elevator_merged_fn) (request_queue_t *, struct request *); -typedef struct request *(elevator_next_req_fn) (request_queue_t *); +typedef int (elevator_dispatch_fn) (request_queue_t *, int); -typedef void (elevator_add_req_fn) (request_queue_t *, struct request *, int); +typedef void (elevator_add_req_fn) (request_queue_t *, struct request *); typedef int (elevator_queue_empty_fn) (request_queue_t *); -typedef void (elevator_remove_req_fn) (request_queue_t *, struct request *); -typedef void (elevator_requeue_req_fn) (request_queue_t *, struct request *); typedef struct request *(elevator_request_list_fn) (request_queue_t *, struct request *); typedef void (elevator_completed_req_fn) (request_queue_t *, struct request *); typedef int (elevator_may_queue_fn) (request_queue_t *, int, struct bio *); typedef int (elevator_set_req_fn) (request_queue_t *, struct request *, struct bio *, gfp_t); typedef void (elevator_put_req_fn) (request_queue_t *, struct request *); +typedef void (elevator_activate_req_fn) (request_queue_t *, struct request *); typedef void (elevator_deactivate_req_fn) (request_queue_t *, struct request *); typedef int (elevator_init_fn) (request_queue_t *, elevator_t *); @@ -31,10 +30,9 @@ struct elevator_ops elevator_merged_fn *elevator_merged_fn; elevator_merge_req_fn *elevator_merge_req_fn; - elevator_next_req_fn *elevator_next_req_fn; + elevator_dispatch_fn *elevator_dispatch_fn; elevator_add_req_fn *elevator_add_req_fn; - elevator_remove_req_fn *elevator_remove_req_fn; - elevator_requeue_req_fn *elevator_requeue_req_fn; + elevator_activate_req_fn *elevator_activate_req_fn; elevator_deactivate_req_fn *elevator_deactivate_req_fn; elevator_queue_empty_fn *elevator_queue_empty_fn; @@ -81,15 +79,15 @@ struct elevator_queue /* * block elevator interface */ +extern void elv_dispatch_sort(request_queue_t *, struct request *); extern void elv_add_request(request_queue_t *, struct request *, int, int); extern void __elv_add_request(request_queue_t *, struct request *, int, int); extern int elv_merge(request_queue_t *, struct request **, struct bio *); extern void elv_merge_requests(request_queue_t *, struct request *, struct request *); extern void elv_merged_request(request_queue_t *, struct request *); -extern void elv_remove_request(request_queue_t *, struct request *); +extern void elv_dequeue_request(request_queue_t *, struct request *); extern void elv_requeue_request(request_queue_t *, struct request *); -extern void elv_deactivate_request(request_queue_t *, struct request *); extern int elv_queue_empty(request_queue_t *); extern struct request *elv_next_request(struct request_queue *q); extern struct request *elv_former_request(request_queue_t *, struct request *); @@ -142,4 +140,6 @@ enum { ELV_MQUEUE_MUST, }; +#define rq_end_sector(rq) ((rq)->sector + (rq)->nr_sectors) + #endif |