diff options
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-cgroup.c | 16 | ||||
-rw-r--r-- | block/blk-cgroup.h | 14 | ||||
-rw-r--r-- | block/blk-core.c | 646 | ||||
-rw-r--r-- | block/blk-exec.c | 4 | ||||
-rw-r--r-- | block/blk-flush.c | 439 | ||||
-rw-r--r-- | block/blk-lib.c | 2 | ||||
-rw-r--r-- | block/blk-merge.c | 6 | ||||
-rw-r--r-- | block/blk-settings.c | 15 | ||||
-rw-r--r-- | block/blk-sysfs.c | 2 | ||||
-rw-r--r-- | block/blk-throttle.c | 139 | ||||
-rw-r--r-- | block/blk.h | 16 | ||||
-rw-r--r-- | block/cfq-iosched.c | 163 | ||||
-rw-r--r-- | block/cfq.h | 6 | ||||
-rw-r--r-- | block/deadline-iosched.c | 9 | ||||
-rw-r--r-- | block/elevator.c | 108 | ||||
-rw-r--r-- | block/genhd.c | 18 | ||||
-rw-r--r-- | block/noop-iosched.c | 8 |
17 files changed, 955 insertions, 656 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 455768a3eb9e..2bef5705ce24 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -371,12 +371,14 @@ void blkiocg_update_io_remove_stats(struct blkio_group *blkg, } EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats); -void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time) +void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time, + unsigned long unaccounted_time) { unsigned long flags; spin_lock_irqsave(&blkg->stats_lock, flags); blkg->stats.time += time; + blkg->stats.unaccounted_time += unaccounted_time; spin_unlock_irqrestore(&blkg->stats_lock, flags); } EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used); @@ -604,6 +606,9 @@ static uint64_t blkio_get_stat(struct blkio_group *blkg, return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, blkg->stats.sectors, cb, dev); #ifdef CONFIG_DEBUG_BLK_CGROUP + if (type == BLKIO_STAT_UNACCOUNTED_TIME) + return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, + blkg->stats.unaccounted_time, cb, dev); if (type == BLKIO_STAT_AVG_QUEUE_SIZE) { uint64_t sum = blkg->stats.avg_queue_size_sum; uint64_t samples = blkg->stats.avg_queue_size_samples; @@ -1125,6 +1130,9 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft, return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_QUEUED, 1); #ifdef CONFIG_DEBUG_BLK_CGROUP + case BLKIO_PROP_unaccounted_time: + return blkio_read_blkg_stats(blkcg, cft, cb, + BLKIO_STAT_UNACCOUNTED_TIME, 0); case BLKIO_PROP_dequeue: return blkio_read_blkg_stats(blkcg, cft, cb, BLKIO_STAT_DEQUEUE, 0); @@ -1382,6 +1390,12 @@ struct cftype blkio_files[] = { BLKIO_PROP_dequeue), .read_map = blkiocg_file_read_map, }, + { + .name = "unaccounted_time", + .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP, + BLKIO_PROP_unaccounted_time), + .read_map = blkiocg_file_read_map, + }, #endif }; diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index ea4861bdd549..10919fae2d3a 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -49,6 +49,8 @@ enum stat_type { /* All the single valued stats go below this */ BLKIO_STAT_TIME, BLKIO_STAT_SECTORS, + /* Time not charged to this cgroup */ + BLKIO_STAT_UNACCOUNTED_TIME, #ifdef CONFIG_DEBUG_BLK_CGROUP BLKIO_STAT_AVG_QUEUE_SIZE, BLKIO_STAT_IDLE_TIME, @@ -81,6 +83,7 @@ enum blkcg_file_name_prop { BLKIO_PROP_io_serviced, BLKIO_PROP_time, BLKIO_PROP_sectors, + BLKIO_PROP_unaccounted_time, BLKIO_PROP_io_service_time, BLKIO_PROP_io_wait_time, BLKIO_PROP_io_merged, @@ -114,6 +117,8 @@ struct blkio_group_stats { /* total disk time and nr sectors dispatched by this group */ uint64_t time; uint64_t sectors; + /* Time not charged to this cgroup */ + uint64_t unaccounted_time; uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL]; #ifdef CONFIG_DEBUG_BLK_CGROUP /* Sum of number of IOs queued across all samples */ @@ -240,7 +245,7 @@ static inline char *blkg_path(struct blkio_group *blkg) { return NULL; } #endif -#define BLKIO_WEIGHT_MIN 100 +#define BLKIO_WEIGHT_MIN 10 #define BLKIO_WEIGHT_MAX 1000 #define BLKIO_WEIGHT_DEFAULT 500 @@ -293,7 +298,8 @@ extern int blkiocg_del_blkio_group(struct blkio_group *blkg); extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key); void blkiocg_update_timeslice_used(struct blkio_group *blkg, - unsigned long time); + unsigned long time, + unsigned long unaccounted_time); void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes, bool direction, bool sync); void blkiocg_update_completion_stats(struct blkio_group *blkg, @@ -319,7 +325,9 @@ blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; } static inline struct blkio_group * blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; } static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg, - unsigned long time) {} + unsigned long time, + unsigned long unaccounted_time) +{} static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes, bool direction, bool sync) {} static inline void blkiocg_update_completion_stats(struct blkio_group *blkg, diff --git a/block/blk-core.c b/block/blk-core.c index a63336d49f30..59b5c00c0126 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -27,6 +27,7 @@ #include <linux/writeback.h> #include <linux/task_io_accounting_ops.h> #include <linux/fault-inject.h> +#include <linux/list_sort.h> #define CREATE_TRACE_POINTS #include <trace/events/block.h> @@ -149,39 +150,29 @@ EXPORT_SYMBOL(blk_rq_init); static void req_bio_endio(struct request *rq, struct bio *bio, unsigned int nbytes, int error) { - struct request_queue *q = rq->q; - - if (&q->flush_rq != rq) { - if (error) - clear_bit(BIO_UPTODATE, &bio->bi_flags); - else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) - error = -EIO; + if (error) + clear_bit(BIO_UPTODATE, &bio->bi_flags); + else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) + error = -EIO; - if (unlikely(nbytes > bio->bi_size)) { - printk(KERN_ERR "%s: want %u bytes done, %u left\n", - __func__, nbytes, bio->bi_size); - nbytes = bio->bi_size; - } + if (unlikely(nbytes > bio->bi_size)) { + printk(KERN_ERR "%s: want %u bytes done, %u left\n", + __func__, nbytes, bio->bi_size); + nbytes = bio->bi_size; + } - if (unlikely(rq->cmd_flags & REQ_QUIET)) - set_bit(BIO_QUIET, &bio->bi_flags); + if (unlikely(rq->cmd_flags & REQ_QUIET)) + set_bit(BIO_QUIET, &bio->bi_flags); - bio->bi_size -= nbytes; - bio->bi_sector += (nbytes >> 9); + bio->bi_size -= nbytes; + bio->bi_sector += (nbytes >> 9); - if (bio_integrity(bio)) - bio_integrity_advance(bio, nbytes); + if (bio_integrity(bio)) + bio_integrity_advance(bio, nbytes); - if (bio->bi_size == 0) - bio_endio(bio, error); - } else { - /* - * Okay, this is the sequenced flush request in - * progress, just record the error; - */ - if (error && !q->flush_err) - q->flush_err = error; - } + /* don't actually finish bio if it's part of flush sequence */ + if (bio->bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) + bio_endio(bio, error); } void blk_dump_rq_flags(struct request *rq, char *msg) @@ -208,135 +199,43 @@ void blk_dump_rq_flags(struct request *rq, char *msg) EXPORT_SYMBOL(blk_dump_rq_flags); /* - * "plug" the device if there are no outstanding requests: this will - * force the transfer to start only after we have put all the requests - * on the list. - * - * This is called with interrupts off and no requests on the queue and - * with the queue lock held. - */ -void blk_plug_device(struct request_queue *q) + * Make sure that plugs that were pending when this function was entered, + * are now complete and requests pushed to the queue. +*/ +static inline void queue_sync_plugs(struct request_queue *q) { - WARN_ON(!irqs_disabled()); - /* - * don't plug a stopped queue, it must be paired with blk_start_queue() - * which will restart the queueing + * If the current process is plugged and has barriers submitted, + * we will livelock if we don't unplug first. */ - if (blk_queue_stopped(q)) - return; - - if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) { - mod_timer(&q->unplug_timer, jiffies + q->unplug_delay); - trace_block_plug(q); - } -} -EXPORT_SYMBOL(blk_plug_device); - -/** - * blk_plug_device_unlocked - plug a device without queue lock held - * @q: The &struct request_queue to plug - * - * Description: - * Like @blk_plug_device(), but grabs the queue lock and disables - * interrupts. - **/ -void blk_plug_device_unlocked(struct request_queue *q) -{ - unsigned long flags; - - spin_lock_irqsave(q->queue_lock, flags); - blk_plug_device(q); - spin_unlock_irqrestore(q->queue_lock, flags); -} -EXPORT_SYMBOL(blk_plug_device_unlocked); - -/* - * remove the queue from the plugged list, if present. called with - * queue lock held and interrupts disabled. - */ -int blk_remove_plug(struct request_queue *q) -{ - WARN_ON(!irqs_disabled()); - - if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q)) - return 0; - - del_timer(&q->unplug_timer); - return 1; + blk_flush_plug(current); } -EXPORT_SYMBOL(blk_remove_plug); -/* - * remove the plug and let it rip.. - */ -void __generic_unplug_device(struct request_queue *q) +static void blk_delay_work(struct work_struct *work) { - if (unlikely(blk_queue_stopped(q))) - return; - if (!blk_remove_plug(q) && !blk_queue_nonrot(q)) - return; + struct request_queue *q; - q->request_fn(q); + q = container_of(work, struct request_queue, delay_work.work); + spin_lock_irq(q->queue_lock); + __blk_run_queue(q, false); + spin_unlock_irq(q->queue_lock); } /** - * generic_unplug_device - fire a request queue - * @q: The &struct request_queue in question + * blk_delay_queue - restart queueing after defined interval + * @q: The &struct request_queue in question + * @msecs: Delay in msecs * * Description: - * Linux uses plugging to build bigger requests queues before letting - * the device have at them. If a queue is plugged, the I/O scheduler - * is still adding and merging requests on the queue. Once the queue - * gets unplugged, the request_fn defined for the queue is invoked and - * transfers started. - **/ -void generic_unplug_device(struct request_queue *q) -{ - if (blk_queue_plugged(q)) { - spin_lock_irq(q->queue_lock); - __generic_unplug_device(q); - spin_unlock_irq(q->queue_lock); - } -} -EXPORT_SYMBOL(generic_unplug_device); - -static void blk_backing_dev_unplug(struct backing_dev_info *bdi, - struct page *page) -{ - struct request_queue *q = bdi->unplug_io_data; - - blk_unplug(q); -} - -void blk_unplug_work(struct work_struct *work) -{ - struct request_queue *q = - container_of(work, struct request_queue, unplug_work); - - trace_block_unplug_io(q); - q->unplug_fn(q); -} - -void blk_unplug_timeout(unsigned long data) -{ - struct request_queue *q = (struct request_queue *)data; - - trace_block_unplug_timer(q); - kblockd_schedule_work(q, &q->unplug_work); -} - -void blk_unplug(struct request_queue *q) + * Sometimes queueing needs to be postponed for a little while, to allow + * resources to come back. This function will make sure that queueing is + * restarted around the specified time. + */ +void blk_delay_queue(struct request_queue *q, unsigned long msecs) { - /* - * devices don't necessarily have an ->unplug_fn defined - */ - if (q->unplug_fn) { - trace_block_unplug_io(q); - q->unplug_fn(q); - } + schedule_delayed_work(&q->delay_work, msecs_to_jiffies(msecs)); } -EXPORT_SYMBOL(blk_unplug); +EXPORT_SYMBOL(blk_delay_queue); /** * blk_start_queue - restart a previously stopped queue @@ -372,7 +271,7 @@ EXPORT_SYMBOL(blk_start_queue); **/ void blk_stop_queue(struct request_queue *q) { - blk_remove_plug(q); + cancel_delayed_work(&q->delay_work); queue_flag_set(QUEUE_FLAG_STOPPED, q); } EXPORT_SYMBOL(blk_stop_queue); @@ -390,13 +289,16 @@ EXPORT_SYMBOL(blk_stop_queue); * that its ->make_request_fn will not re-add plugging prior to calling * this function. * + * This function does not cancel any asynchronous activity arising + * out of elevator or throttling code. That would require elevaotor_exit() + * and blk_throtl_exit() to be called with queue lock initialized. + * */ void blk_sync_queue(struct request_queue *q) { - del_timer_sync(&q->unplug_timer); del_timer_sync(&q->timeout); - cancel_work_sync(&q->unplug_work); - throtl_shutdown_timer_wq(q); + cancel_delayed_work_sync(&q->delay_work); + queue_sync_plugs(q); } EXPORT_SYMBOL(blk_sync_queue); @@ -412,14 +314,9 @@ EXPORT_SYMBOL(blk_sync_queue); */ void __blk_run_queue(struct request_queue *q, bool force_kblockd) { - blk_remove_plug(q); - if (unlikely(blk_queue_stopped(q))) return; - if (elv_queue_empty(q)) - return; - /* * Only recurse once to avoid overrunning the stack, let the unplug * handling reinvoke the handler shortly if we already got there. @@ -427,10 +324,8 @@ void __blk_run_queue(struct request_queue *q, bool force_kblockd) if (!force_kblockd && !queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { q->request_fn(q); queue_flag_clear(QUEUE_FLAG_REENTER, q); - } else { - queue_flag_set(QUEUE_FLAG_PLUGGED, q); - kblockd_schedule_work(q, &q->unplug_work); - } + } else + queue_delayed_work(kblockd_workqueue, &q->delay_work, 0); } EXPORT_SYMBOL(__blk_run_queue); @@ -457,6 +352,11 @@ void blk_put_queue(struct request_queue *q) kobject_put(&q->kobj); } +/* + * Note: If a driver supplied the queue lock, it should not zap that lock + * unexpectedly as some queue cleanup components like elevator_exit() and + * blk_throtl_exit() need queue lock. + */ void blk_cleanup_queue(struct request_queue *q) { /* @@ -475,6 +375,8 @@ void blk_cleanup_queue(struct request_queue *q) if (q->elevator) elevator_exit(q->elevator); + blk_throtl_exit(q); + blk_put_queue(q); } EXPORT_SYMBOL(blk_cleanup_queue); @@ -517,8 +419,6 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) if (!q) return NULL; - q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug; - q->backing_dev_info.unplug_io_data = q; q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; q->backing_dev_info.state = 0; @@ -538,17 +438,24 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, laptop_mode_timer_fn, (unsigned long) q); - init_timer(&q->unplug_timer); setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); INIT_LIST_HEAD(&q->timeout_list); - INIT_LIST_HEAD(&q->pending_flushes); - INIT_WORK(&q->unplug_work, blk_unplug_work); + INIT_LIST_HEAD(&q->flush_queue[0]); + INIT_LIST_HEAD(&q->flush_queue[1]); + INIT_LIST_HEAD(&q->flush_data_in_flight); + INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); kobject_init(&q->kobj, &blk_queue_ktype); mutex_init(&q->sysfs_lock); spin_lock_init(&q->__queue_lock); + /* + * By default initialize queue_lock to internal lock and driver can + * override it later if need be. + */ + q->queue_lock = &q->__queue_lock; + return q; } EXPORT_SYMBOL(blk_alloc_queue_node); @@ -631,9 +538,11 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn, q->request_fn = rfn; q->prep_rq_fn = NULL; q->unprep_rq_fn = NULL; - q->unplug_fn = generic_unplug_device; q->queue_flags = QUEUE_FLAG_DEFAULT; - q->queue_lock = lock; + + /* Override internal queue lock with supplied lock pointer */ + if (lock) + q->queue_lock = lock; /* * This also sets hw/phys segments, boundary and size @@ -666,6 +575,8 @@ int blk_get_queue(struct request_queue *q) static inline void blk_free_request(struct request_queue *q, struct request *rq) { + BUG_ON(rq->cmd_flags & REQ_ON_PLUG); + if (rq->cmd_flags & REQ_ELVPRIV) elv_put_request(q, rq); mempool_free(rq, q->rq.rq_pool); @@ -762,6 +673,25 @@ static void freed_request(struct request_queue *q, int sync, int priv) } /* + * Determine if elevator data should be initialized when allocating the + * request associated with @bio. + */ +static bool blk_rq_should_init_elevator(struct bio *bio) +{ + if (!bio) + return true; + + /* + * Flush requests do not use the elevator so skip initialization. + * This allows a request to share the flush and elevator data. + */ + if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) + return false; + + return true; +} + +/* * Get a free request, queue_lock must be held. * Returns NULL on failure, with queue_lock held. * Returns !NULL on success, with queue_lock *not held*. @@ -773,7 +703,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags, struct request_list *rl = &q->rq; struct io_context *ioc = NULL; const bool is_sync = rw_is_sync(rw_flags) != 0; - int may_queue, priv; + int may_queue, priv = 0; may_queue = elv_may_queue(q, rw_flags); if (may_queue == ELV_MQUEUE_NO) @@ -817,9 +747,11 @@ static struct request *get_request(struct request_queue *q, int rw_flags, rl->count[is_sync]++; rl->starved[is_sync] = 0; - priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); - if (priv) - rl->elvpriv++; + if (blk_rq_should_init_elevator(bio)) { + priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags); + if (priv) + rl->elvpriv++; + } if (blk_queue_io_stat(q)) rw_flags |= REQ_IO_STAT; @@ -866,8 +798,8 @@ out: } /* - * No available requests for this queue, unplug the device and wait for some - * requests to become available. + * No available requests for this queue, wait for some requests to become + * available. * * Called with q->queue_lock held, and returns with it unlocked. */ @@ -888,7 +820,6 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags, trace_block_sleeprq(q, bio, rw_flags & 1); - __generic_unplug_device(q); spin_unlock_irq(q->queue_lock); io_schedule(); @@ -1010,6 +941,13 @@ void blk_requeue_request(struct request_queue *q, struct request *rq) } EXPORT_SYMBOL(blk_requeue_request); +static void add_acct_request(struct request_queue *q, struct request *rq, + int where) +{ + drive_stat_acct(rq, 1); + __elv_add_request(q, rq, where); +} + /** * blk_insert_request - insert a special request into a request queue * @q: request queue where request should be inserted @@ -1052,8 +990,7 @@ void blk_insert_request(struct request_queue *q, struct request *rq, if (blk_rq_tagged(rq)) blk_queue_end_tag(q, rq); - drive_stat_acct(rq, 1); - __elv_add_request(q, rq, where, 0); + add_acct_request(q, rq, where); __blk_run_queue(q, false); spin_unlock_irqrestore(q->queue_lock, flags); } @@ -1174,6 +1111,113 @@ void blk_add_request_payload(struct request *rq, struct page *page, } EXPORT_SYMBOL_GPL(blk_add_request_payload); +static bool bio_attempt_back_merge(struct request_queue *q, struct request *req, + struct bio *bio) +{ + const int ff = bio->bi_rw & REQ_FAILFAST_MASK; + + /* + * Debug stuff, kill later + */ + if (!rq_mergeable(req)) { + blk_dump_rq_flags(req, "back"); + return false; + } + + if (!ll_back_merge_fn(q, req, bio)) + return false; + + trace_block_bio_backmerge(q, bio); + + if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) + blk_rq_set_mixed_merge(req); + + req->biotail->bi_next = bio; + req->biotail = bio; + req->__data_len += bio->bi_size; + req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); + + drive_stat_acct(req, 0); + return true; +} + +static bool bio_attempt_front_merge(struct request_queue *q, + struct request *req, struct bio *bio) +{ + const int ff = bio->bi_rw & REQ_FAILFAST_MASK; + sector_t sector; + + /* + * Debug stuff, kill later + */ + if (!rq_mergeable(req)) { + blk_dump_rq_flags(req, "front"); + return false; + } + + if (!ll_front_merge_fn(q, req, bio)) + return false; + + trace_block_bio_frontmerge(q, bio); + + if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) + blk_rq_set_mixed_merge(req); + + sector = bio->bi_sector; + + bio->bi_next = req->bio; + req->bio = bio; + + /* + * may not be valid. if the low level driver said + * it didn't need a bounce buffer then it better + * not touch req->buffer either... + */ + req->buffer = bio_data(bio); + req->__sector = bio->bi_sector; + req->__data_len += bio->bi_size; + req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); + + drive_stat_acct(req, 0); + return true; +} + +/* + * Attempts to merge with the plugged list in the current process. Returns + * true if merge was succesful, otherwise false. + */ +static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q, + struct bio *bio) +{ + struct blk_plug *plug; + struct request *rq; + bool ret = false; + + plug = tsk->plug; + if (!plug) + goto out; + + list_for_each_entry_reverse(rq, &plug->list, queuelist) { + int el_ret; + + if (rq->q != q) + continue; + + el_ret = elv_try_merge(rq, bio); + if (el_ret == ELEVATOR_BACK_MERGE) { + ret = bio_attempt_back_merge(q, rq, bio); + if (ret) + break; + } else if (el_ret == ELEVATOR_FRONT_MERGE) { + ret = bio_attempt_front_merge(q, rq, bio); + if (ret) + break; + } + } +out: + return ret; +} + void init_request_from_bio(struct request *req, struct bio *bio) { req->cpu = bio->bi_comp_cpu; @@ -1189,26 +1233,12 @@ void init_request_from_bio(struct request *req, struct bio *bio) blk_rq_bio_prep(req->q, req, bio); } -/* - * Only disabling plugging for non-rotational devices if it does tagging - * as well, otherwise we do need the proper merging - */ -static inline bool queue_should_plug(struct request_queue *q) -{ - return !(blk_queue_nonrot(q) && blk_queue_tagged(q)); -} - static int __make_request(struct request_queue *q, struct bio *bio) { - struct request *req; - int el_ret; - unsigned int bytes = bio->bi_size; - const unsigned short prio = bio_prio(bio); const bool sync = !!(bio->bi_rw & REQ_SYNC); - const bool unplug = !!(bio->bi_rw & REQ_UNPLUG); - const unsigned long ff = bio->bi_rw & REQ_FAILFAST_MASK; - int where = ELEVATOR_INSERT_SORT; - int rw_flags; + struct blk_plug *plug; + int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; + struct request *req; /* * low level driver can indicate that it wants pages above a @@ -1217,78 +1247,36 @@ static int __make_request(struct request_queue *q, struct bio *bio) */ blk_queue_bounce(q, &bio); - spin_lock_irq(q->queue_lock); - if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { - where = ELEVATOR_INSERT_FRONT; + spin_lock_irq(q->queue_lock); + where = ELEVATOR_INSERT_FLUSH; goto get_rq; } - if (elv_queue_empty(q)) - goto get_rq; - - el_ret = elv_merge(q, &req, bio); - switch (el_ret) { - case ELEVATOR_BACK_MERGE: - BUG_ON(!rq_mergeable(req)); - - if (!ll_back_merge_fn(q, req, bio)) - break; - - trace_block_bio_backmerge(q, bio); - - if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) - blk_rq_set_mixed_merge(req); - - req->biotail->bi_next = bio; - req->biotail = bio; - req->__data_len += bytes; - req->ioprio = ioprio_best(req->ioprio, prio); - if (!blk_rq_cpu_valid(req)) - req->cpu = bio->bi_comp_cpu; - drive_stat_acct(req, 0); - elv_bio_merged(q, req, bio); - if (!attempt_back_merge(q, req)) - elv_merged_request(q, req, el_ret); + /* + * Check if we can merge with the plugged list before grabbing + * any locks. + */ + if (attempt_plug_merge(current, q, bio)) goto out; - case ELEVATOR_FRONT_MERGE: - BUG_ON(!rq_mergeable(req)); - - if (!ll_front_merge_fn(q, req, bio)) - break; - - trace_block_bio_frontmerge(q, bio); + spin_lock_irq(q->queue_lock); - if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) { - blk_rq_set_mixed_merge(req); - req->cmd_flags &= ~REQ_FAILFAST_MASK; - req->cmd_flags |= ff; + el_ret = elv_merge(q, &req, bio); + if (el_ret == ELEVATOR_BACK_MERGE) { + BUG_ON(req->cmd_flags & REQ_ON_PLUG); + if (bio_attempt_back_merge(q, req, bio)) { + if (!attempt_back_merge(q, req)) + elv_merged_request(q, req, el_ret); + goto out_unlock; + } + } else if (el_ret == ELEVATOR_FRONT_MERGE) { + BUG_ON(req->cmd_flags & REQ_ON_PLUG); + if (bio_attempt_front_merge(q, req, bio)) { + if (!attempt_front_merge(q, req)) + elv_merged_request(q, req, el_ret); + goto out_unlock; } - - bio->bi_next = req->bio; - req->bio = bio; - - /* - * may not be valid. if the low level driver said - * it didn't need a bounce buffer then it better - * not touch req->buffer either... - */ - req->buffer = bio_data(bio); - req->__sector = bio->bi_sector; - req->__data_len += bytes; - req->ioprio = ioprio_best(req->ioprio, prio); - if (!blk_rq_cpu_valid(req)) - req->cpu = bio->bi_comp_cpu; - drive_stat_acct(req, 0); - elv_bio_merged(q, req, bio); - if (!attempt_front_merge(q, req)) - elv_merged_request(q, req, el_ret); - goto out; - - /* ELV_NO_MERGE: elevator says don't/can't merge. */ - default: - ; } get_rq: @@ -1315,20 +1303,35 @@ get_rq: */ init_request_from_bio(req, bio); - spin_lock_irq(q->queue_lock); if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) || - bio_flagged(bio, BIO_CPU_AFFINE)) - req->cpu = blk_cpu_to_group(smp_processor_id()); - if (queue_should_plug(q) && elv_queue_empty(q)) - blk_plug_device(q); - - /* insert the request into the elevator */ - drive_stat_acct(req, 1); - __elv_add_request(q, req, where, 0); + bio_flagged(bio, BIO_CPU_AFFINE)) { + req->cpu = blk_cpu_to_group(get_cpu()); + put_cpu(); + } + + plug = current->plug; + if (plug) { + if (!plug->should_sort && !list_empty(&plug->list)) { + struct request *__rq; + + __rq = list_entry_rq(plug->list.prev); + if (__rq->q != q) + plug->should_sort = 1; + } + /* + * Debug flag, kill later + */ + req->cmd_flags |= REQ_ON_PLUG; + list_add_tail(&req->queuelist, &plug->list); + drive_stat_acct(req, 1); + } else { + spin_lock_irq(q->queue_lock); + add_acct_request(q, req, where); + __blk_run_queue(q, false); +out_unlock: + spin_unlock_irq(q->queue_lock); + } out: - if (unplug || !queue_should_plug(q)) - __generic_unplug_device(q); - spin_unlock_irq(q->queue_lock); return 0; } @@ -1731,9 +1734,7 @@ int blk_insert_cloned_request(struct request_queue *q, struct request *rq) */ BUG_ON(blk_queued_rq(rq)); - drive_stat_acct(rq, 1); - __elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0); - + add_acct_request(q, rq, ELEVATOR_INSERT_BACK); spin_unlock_irqrestore(q->queue_lock, flags); return 0; @@ -1805,7 +1806,7 @@ static void blk_account_io_done(struct request *req) * normal IO on queueing nor completion. Accounting the * containing request is enough. */ - if (blk_do_io_stat(req) && req != &req->q->flush_rq) { + if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) { unsigned long duration = jiffies - req->start_time; const int rw = rq_data_dir(req); struct hd_struct *part; @@ -2628,6 +2629,113 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) } EXPORT_SYMBOL(kblockd_schedule_work); +int kblockd_schedule_delayed_work(struct request_queue *q, + struct delayed_work *dwork, unsigned long delay) +{ + return queue_delayed_work(kblockd_workqueue, dwork, delay); +} +EXPORT_SYMBOL(kblockd_schedule_delayed_work); + +#define PLUG_MAGIC 0x91827364 + +void blk_start_plug(struct blk_plug *plug) +{ + struct task_struct *tsk = current; + + plug->magic = PLUG_MAGIC; + INIT_LIST_HEAD(&plug->list); + plug->should_sort = 0; + + /* + * If this is a nested plug, don't actually assign it. It will be + * flushed on its own. + */ + if (!tsk->plug) { + /* + * Store ordering should not be needed here, since a potential + * preempt will imply a full memory barrier + */ + tsk->plug = plug; + } +} +EXPORT_SYMBOL(blk_start_plug); + +static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) +{ + struct request *rqa = container_of(a, struct request, queuelist); + struct request *rqb = container_of(b, struct request, queuelist); + + return !(rqa->q == rqb->q); +} + +static void flush_plug_list(struct blk_plug *plug) +{ + struct request_queue *q; + unsigned long flags; + struct request *rq; + + BUG_ON(plug->magic != PLUG_MAGIC); + + if (list_empty(&plug->list)) + return; + + if (plug->should_sort) + list_sort(NULL, &plug->list, plug_rq_cmp); + + q = NULL; + local_irq_save(flags); + while (!list_empty(&plug->list)) { + rq = list_entry_rq(plug->list.next); + list_del_init(&rq->queuelist); + BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG)); + BUG_ON(!rq->q); + if (rq->q != q) { + if (q) { + __blk_run_queue(q, false); + spin_unlock(q->queue_lock); + } + q = rq->q; + spin_lock(q->queue_lock); + } + rq->cmd_flags &= ~REQ_ON_PLUG; + + /* + * rq is already accounted, so use raw insert + */ + __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); + } + + if (q) { + __blk_run_queue(q, false); + spin_unlock(q->queue_lock); + } + + BUG_ON(!list_empty(&plug->list)); + local_irq_restore(flags); +} + +static void __blk_finish_plug(struct task_struct *tsk, struct blk_plug *plug) +{ + flush_plug_list(plug); + + if (plug == tsk->plug) + tsk->plug = NULL; +} + +void blk_finish_plug(struct blk_plug *plug) +{ + if (plug) + __blk_finish_plug(current, plug); +} +EXPORT_SYMBOL(blk_finish_plug); + +void __blk_flush_plug(struct task_struct *tsk, struct blk_plug *plug) +{ + __blk_finish_plug(tsk, plug); + tsk->plug = plug; +} +EXPORT_SYMBOL(__blk_flush_plug); + int __init blk_dev_init(void) { BUILD_BUG_ON(__REQ_NR_BITS > 8 * diff --git a/block/blk-exec.c b/block/blk-exec.c index cf1456a02acd..7482b7fa863b 100644 --- a/block/blk-exec.c +++ b/block/blk-exec.c @@ -54,8 +54,8 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, rq->end_io = done; WARN_ON(irqs_disabled()); spin_lock_irq(q->queue_lock); - __elv_add_request(q, rq, where, 1); - __generic_unplug_device(q); + __elv_add_request(q, rq, where); + __blk_run_queue(q, false); /* the queue is stopped so it won't be plugged+unplugged */ if (rq->cmd_type == REQ_TYPE_PM_RESUME) q->request_fn(q); diff --git a/block/blk-flush.c b/block/blk-flush.c index b27d0208611b..93d5fd8e51eb 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -1,6 +1,69 @@ /* * Functions to sequence FLUSH and FUA writes. + * + * Copyright (C) 2011 Max Planck Institute for Gravitational Physics + * Copyright (C) 2011 Tejun Heo <tj@kernel.org> + * + * This file is released under the GPLv2. + * + * REQ_{FLUSH|FUA} requests are decomposed to sequences consisted of three + * optional steps - PREFLUSH, DATA and POSTFLUSH - according to the request + * properties and hardware capability. + * + * If a request doesn't have data, only REQ_FLUSH makes sense, which |