diff options
| -rw-r--r-- | Documentation/block/queue-sysfs.txt | 7 | ||||
| -rw-r--r-- | block/Kconfig | 26 | ||||
| -rw-r--r-- | block/blk-core.c | 17 | ||||
| -rw-r--r-- | block/blk-mq.c | 26 | ||||
| -rw-r--r-- | block/blk-settings.c | 4 | ||||
| -rw-r--r-- | block/blk-sysfs.c | 88 | ||||
| -rw-r--r-- | block/cfq-iosched.c | 14 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 3 |
8 files changed, 181 insertions, 4 deletions
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt index 2a3904030dea..87abf1ac2939 100644 --- a/Documentation/block/queue-sysfs.txt +++ b/Documentation/block/queue-sysfs.txt @@ -169,5 +169,12 @@ This is the number of bytes the device can write in a single write-same command. A value of '0' means write-same is not supported by this device. +wb_lat_usec (RW) +---------------- +If the device is registered for writeback throttling, then this file shows +the target minimum read latency. If this latency is exceeded in a given +window of time (see wb_window_usec), then the writeback throttling will start +scaling back writes. + Jens Axboe <jens.axboe@oracle.com>, February 2009 diff --git a/block/Kconfig b/block/Kconfig index 3a024440a669..8bf114a3858a 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -121,6 +121,32 @@ config BLK_CMDLINE_PARSER See Documentation/block/cmdline-partition.txt for more information. +config BLK_WBT + bool "Enable support for block device writeback throttling" + default n + ---help--- + Enabling this option enables the block layer to throttle buffered + background writeback from the VM, making it more smooth and having + less impact on foreground operations. The throttling is done + dynamically on an algorithm loosely based on CoDel, factoring in + the realtime performance of the disk. + +config BLK_WBT_SQ + bool "Single queue writeback throttling" + default n + depends on BLK_WBT + ---help--- + Enable writeback throttling by default on legacy single queue devices + +config BLK_WBT_MQ + bool "Multiqueue writeback throttling" + default y + depends on BLK_WBT + ---help--- + Enable writeback throttling by default on multiqueue devices. + Multiqueue currently doesn't have support for IO scheduling, + enabling this option is recommended. + menu "Partition Types" source "block/partitions/Kconfig" diff --git a/block/blk-core.c b/block/blk-core.c index 216372b01624..59f8129a4295 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -39,6 +39,7 @@ #include "blk.h" #include "blk-mq.h" +#include "blk-wbt.h" EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); @@ -882,6 +883,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, fail: blk_free_flush_queue(q->fq); + wbt_exit(q); return NULL; } EXPORT_SYMBOL(blk_init_allocated_queue); @@ -1344,6 +1346,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq) blk_delete_timer(rq); blk_clear_rq_complete(rq); trace_block_rq_requeue(q, rq); + wbt_requeue(q->rq_wb, &rq->issue_stat); if (rq->rq_flags & RQF_QUEUED) blk_queue_end_tag(q, rq); @@ -1436,6 +1439,8 @@ void __blk_put_request(struct request_queue *q, struct request *req) /* this is a bio leak */ WARN_ON(req->bio != NULL); + wbt_done(q->rq_wb, &req->issue_stat); + /* * Request may not have originated from ll_rw_blk. if not, * it didn't come out of our reserved rq pools @@ -1663,6 +1668,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) int el_ret, where = ELEVATOR_INSERT_SORT; struct request *req; unsigned int request_count = 0; + unsigned int wb_acct; /* * low level driver can indicate that it wants pages above a @@ -1715,17 +1721,22 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) } get_rq: + wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock); + /* * Grab a free request. This is might sleep but can not fail. * Returns with the queue unlocked. */ req = get_request(q, bio->bi_opf, bio, GFP_NOIO); if (IS_ERR(req)) { + __wbt_done(q->rq_wb, wb_acct); bio->bi_error = PTR_ERR(req); bio_endio(bio); goto out_unlock; } + wbt_track(&req->issue_stat, wb_acct); + /* * After dropping the lock and possibly sleeping here, our request * may now be mergeable after it had proven unmergeable (above). @@ -2467,6 +2478,7 @@ void blk_start_request(struct request *req) if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) { blk_stat_set_issue_time(&req->issue_stat); req->rq_flags |= RQF_STATS; + wbt_issue(req->q->rq_wb, &req->issue_stat); } /* @@ -2708,9 +2720,10 @@ void blk_finish_request(struct request *req, int error) blk_account_io_done(req); - if (req->end_io) + if (req->end_io) { + wbt_done(req->q->rq_wb, &req->issue_stat); req->end_io(req, error); - else { + } else { if (blk_bidi_rq(req)) __blk_put_request(req->next_rq->q, req->next_rq); diff --git a/block/blk-mq.c b/block/blk-mq.c index 19795886d46e..d180c989a0e5 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -31,6 +31,7 @@ #include "blk-mq.h" #include "blk-mq-tag.h" #include "blk-stat.h" +#include "blk-wbt.h" static DEFINE_MUTEX(all_q_mutex); static LIST_HEAD(all_q_list); @@ -326,6 +327,8 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, if (rq->rq_flags & RQF_MQ_INFLIGHT) atomic_dec(&hctx->nr_active); + + wbt_done(q->rq_wb, &rq->issue_stat); rq->rq_flags = 0; clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); @@ -354,6 +357,7 @@ inline void __blk_mq_end_request(struct request *rq, int error) blk_account_io_done(rq); if (rq->end_io) { + wbt_done(rq->q->rq_wb, &rq->issue_stat); rq->end_io(rq, error); } else { if (unlikely(blk_bidi_rq(rq))) @@ -471,6 +475,7 @@ void blk_mq_start_request(struct request *rq) if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) { blk_stat_set_issue_time(&rq->issue_stat); rq->rq_flags |= RQF_STATS; + wbt_issue(q->rq_wb, &rq->issue_stat); } blk_add_timer(rq); @@ -508,6 +513,7 @@ static void __blk_mq_requeue_request(struct request *rq) struct request_queue *q = rq->q; trace_block_rq_requeue(q, rq); + wbt_requeue(q->rq_wb, &rq->issue_stat); if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { if (q->dma_drain_size && blk_rq_bytes(rq)) @@ -1339,6 +1345,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) struct blk_plug *plug; struct request *same_queue_rq = NULL; blk_qc_t cookie; + unsigned int wb_acct; blk_queue_bounce(q, &bio); @@ -1353,9 +1360,15 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq)) return BLK_QC_T_NONE; + wb_acct = wbt_wait(q->rq_wb, bio, NULL); + rq = blk_mq_map_request(q, bio, &data); - if (unlikely(!rq)) + if (unlikely(!rq)) { + __wbt_done(q->rq_wb, wb_acct); return BLK_QC_T_NONE; + } + + wbt_track(&rq->issue_stat, wb_acct); cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num); @@ -1439,6 +1452,7 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) struct blk_mq_alloc_data data; struct request *rq; blk_qc_t cookie; + unsigned int wb_acct; blk_queue_bounce(q, &bio); @@ -1455,9 +1469,15 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) } else request_count = blk_plug_queued_count(q); + wb_acct = wbt_wait(q->rq_wb, bio, NULL); + rq = blk_mq_map_request(q, bio, &data); - if (unlikely(!rq)) + if (unlikely(!rq)) { + __wbt_done(q->rq_wb, wb_acct); return BLK_QC_T_NONE; + } + + wbt_track(&rq->issue_stat, wb_acct); cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num); @@ -2139,6 +2159,8 @@ void blk_mq_free_queue(struct request_queue *q) list_del_init(&q->all_q_node); mutex_unlock(&all_q_mutex); + wbt_exit(q); + blk_mq_del_queue_tag_set(q); blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); diff --git a/block/blk-settings.c b/block/blk-settings.c index 9cf053759363..c7ccabc0ec3e 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -13,6 +13,7 @@ #include <linux/gfp.h> #include "blk.h" +#include "blk-wbt.h" unsigned long blk_max_low_pfn; EXPORT_SYMBOL(blk_max_low_pfn); @@ -845,6 +846,7 @@ EXPORT_SYMBOL_GPL(blk_queue_flush_queueable); void blk_set_queue_depth(struct request_queue *q, unsigned int depth) { q->queue_depth = depth; + wbt_set_queue_depth(q->rq_wb, depth); } EXPORT_SYMBOL(blk_set_queue_depth); @@ -868,6 +870,8 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua) else queue_flag_clear(QUEUE_FLAG_FUA, q); spin_unlock_irq(q->queue_lock); + + wbt_set_write_cache(q->rq_wb, test_bit(QUEUE_FLAG_WC, &q->queue_flags)); } EXPORT_SYMBOL_GPL(blk_queue_write_cache); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 9cdb7247727a..9262d2d60a09 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -13,6 +13,7 @@ #include "blk.h" #include "blk-mq.h" +#include "blk-wbt.h" struct queue_sysfs_entry { struct attribute attr; @@ -41,6 +42,19 @@ queue_var_store(unsigned long *var, const char *page, size_t count) return count; } +static ssize_t queue_var_store64(u64 *var, const char *page) +{ + int err; + u64 v; + + err = kstrtou64(page, 10, &v); + if (err < 0) + return err; + + *var = v; + return 0; +} + static ssize_t queue_requests_show(struct request_queue *q, char *page) { return queue_var_show(q->nr_requests, (page)); @@ -364,6 +378,32 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, return ret; } +static ssize_t queue_wb_lat_show(struct request_queue *q, char *page) +{ + if (!q->rq_wb) + return -EINVAL; + + return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000)); +} + +static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page, + size_t count) +{ + ssize_t ret; + u64 val; + + if (!q->rq_wb) + return -EINVAL; + + ret = queue_var_store64(&val, page); + if (ret < 0) + return ret; + + q->rq_wb->min_lat_nsec = val * 1000ULL; + wbt_update_limits(q->rq_wb); + return count; +} + static ssize_t queue_wc_show(struct request_queue *q, char *page) { if (test_bit(QUEUE_FLAG_WC, &q->queue_flags)) @@ -578,6 +618,12 @@ static struct queue_sysfs_entry queue_stats_entry = { .show = queue_stats_show, }; +static struct queue_sysfs_entry queue_wb_lat_entry = { + .attr = {.name = "wbt_lat_usec", .mode = S_IRUGO | S_IWUSR }, + .show = queue_wb_lat_show, + .store = queue_wb_lat_store, +}; + static struct attribute *default_attrs[] = { &queue_requests_entry.attr, &queue_ra_entry.attr, @@ -608,6 +654,7 @@ static struct attribute *default_attrs[] = { &queue_wc_entry.attr, &queue_dax_entry.attr, &queue_stats_entry.attr, + &queue_wb_lat_entry.attr, NULL, }; @@ -682,6 +729,7 @@ static void blk_release_queue(struct kobject *kobj) struct request_queue *q = container_of(kobj, struct request_queue, kobj); + wbt_exit(q); bdi_exit(&q->backing_dev_info); blkcg_exit_queue(q); @@ -722,6 +770,44 @@ struct kobj_type blk_queue_ktype = { .release = blk_release_queue, }; +static void blk_wb_stat_get(void *data, struct blk_rq_stat *stat) +{ + blk_queue_stat_get(data, stat); +} + +static void blk_wb_stat_clear(void *data) +{ + blk_stat_clear(data); +} + +static bool blk_wb_stat_is_current(struct blk_rq_stat *stat) +{ + return blk_stat_is_current(stat); +} + +static struct wb_stat_ops wb_stat_ops = { + .get = blk_wb_stat_get, + .is_current = blk_wb_stat_is_current, + .clear = blk_wb_stat_clear, +}; + +static void blk_wb_init(struct request_queue *q) +{ +#ifndef CONFIG_BLK_WBT_MQ + if (q->mq_ops) + return; +#endif +#ifndef CONFIG_BLK_WBT_SQ + if (q->request_fn) + return; +#endif + + /* + * If this fails, we don't get throttling + */ + wbt_init(q, &wb_stat_ops); +} + int blk_register_queue(struct gendisk *disk) { int ret; @@ -761,6 +847,8 @@ int blk_register_queue(struct gendisk *disk) if (q->mq_ops) blk_mq_register_dev(dev, q); + blk_wb_init(q); + if (!q->request_fn) return 0; diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 61010511c5a0..e280d08ef6d7 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -16,6 +16,7 @@ #include <linux/blktrace_api.h> #include <linux/blk-cgroup.h> #include "blk.h" +#include "blk-wbt.h" /* * tunables @@ -3762,9 +3763,11 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) struct cfq_data *cfqd = cic_to_cfqd(cic); struct cfq_queue *cfqq; uint64_t serial_nr; + bool nonroot_cg; rcu_read_lock(); serial_nr = bio_blkcg(bio)->css.serial_nr; + nonroot_cg = bio_blkcg(bio) != &blkcg_root; rcu_read_unlock(); /* @@ -3775,6 +3778,17 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) return; /* + * If we have a non-root cgroup, we can depend on that to + * do proper throttling of writes. Turn off wbt for that + * case. + */ + if (nonroot_cg) { + struct request_queue *q = cfqd->queue; + + wbt_disable(q->rq_wb); + } + + /* * Drop reference to queues. New queues will be assigned in new * group upon arrival of fresh requests. */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 303723a2e5b8..15da9e430f90 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -38,6 +38,7 @@ struct bsg_job; struct blkcg_gq; struct blk_flush_queue; struct pr_ops; +struct rq_wb; #define BLKDEV_MIN_RQ 4 #define BLKDEV_MAX_RQ 128 /* Default maximum */ @@ -383,6 +384,8 @@ struct request_queue { int nr_rqs[2]; /* # allocated [a]sync rqs */ int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */ + struct rq_wb *rq_wb; + /* * If blkcg is not used, @q->root_rl serves all requests. If blkcg * is used, root blkg allocates from @q->root_rl and all other |