From 522a777566f5669606a1227bf13f3fb40963780b Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Wed, 9 May 2018 02:08:53 -0700 Subject: [PATCH] block: consolidate struct request timestamp fields Currently, struct request has four timestamp fields: - A start time, set at get_request time, in jiffies, used for iostats - An I/O start time, set at start_request time, in ktime nanoseconds, used for blk-stats (i.e., wbt, kyber, hybrid polling) - Another start time and another I/O start time, used for cfq and bfq These can all be consolidated into one start time and one I/O start time, both in ktime nanoseconds, shaving off up to 16 bytes from struct request depending on the kernel config. Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 4 ++-- block/blk-core.c | 17 ++++++++--------- block/blk-merge.c | 11 +++++------ block/blk-mq.c | 10 +++++----- block/blk-stat.c | 5 ++--- block/blk-stat.h | 2 +- block/blk.h | 2 +- block/cfq-iosched.c | 15 +++------------ drivers/md/dm-rq.c | 2 +- include/linux/blkdev.h | 38 ++------------------------------------ 10 files changed, 30 insertions(+), 76 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 771ae9730ac6..ebc264c87a09 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -4778,8 +4778,8 @@ static void bfq_finish_requeue_request(struct request *rq) if (rq->rq_flags & RQF_STARTED) bfqg_stats_update_completion(bfqq_group(bfqq), - rq_start_time_ns(rq), - rq_io_start_time_ns(rq), + rq->start_time_ns, + rq->io_start_time_ns, rq->cmd_flags); if (likely(rq->rq_flags & RQF_STARTED)) { diff --git a/block/blk-core.c b/block/blk-core.c index 33d5c7d85da1..1418a1ccd80d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -196,8 +196,7 @@ void blk_rq_init(struct request_queue *q, struct request *rq) RB_CLEAR_NODE(&rq->rb_node); rq->tag = -1; rq->internal_tag = -1; - rq->start_time = jiffies; - set_start_time_ns(rq); + rq->start_time_ns = ktime_get_ns(); rq->part = NULL; seqcount_init(&rq->gstate_seq); u64_stats_init(&rq->aborted_gstate_sync); @@ -2726,7 +2725,7 @@ void blk_account_io_completion(struct request *req, unsigned int bytes) } } -void blk_account_io_done(struct request *req) +void blk_account_io_done(struct request *req, u64 now) { /* * Account IO completion. flush_rq isn't accounted as a @@ -2734,11 +2733,12 @@ void blk_account_io_done(struct request *req) * containing request is enough. */ if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) { - unsigned long duration = jiffies - req->start_time; + unsigned long duration; const int rw = rq_data_dir(req); struct hd_struct *part; int cpu; + duration = nsecs_to_jiffies(now - req->start_time_ns); cpu = part_stat_lock(); part = req->part; @@ -2969,10 +2969,8 @@ static void blk_dequeue_request(struct request *rq) * and to it is freed is accounted as io that is in progress at * the driver side. */ - if (blk_account_rq(rq)) { + if (blk_account_rq(rq)) q->in_flight[rq_is_sync(rq)]++; - set_io_start_time_ns(rq); - } } /** @@ -3192,12 +3190,13 @@ EXPORT_SYMBOL_GPL(blk_unprep_request); void blk_finish_request(struct request *req, blk_status_t error) { struct request_queue *q = req->q; + u64 now = ktime_get_ns(); lockdep_assert_held(req->q->queue_lock); WARN_ON_ONCE(q->mq_ops); if (req->rq_flags & RQF_STATS) - blk_stat_add(req); + blk_stat_add(req, now); if (req->rq_flags & RQF_QUEUED) blk_queue_end_tag(q, req); @@ -3212,7 +3211,7 @@ void blk_finish_request(struct request *req, blk_status_t error) if (req->rq_flags & RQF_DONTPREP) blk_unprep_request(req); - blk_account_io_done(req); + blk_account_io_done(req, now); if (req->end_io) { wbt_done(req->q->rq_wb, req); diff --git a/block/blk-merge.c b/block/blk-merge.c index 782940c65d8a..5573d0fbec53 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -724,13 +724,12 @@ static struct request *attempt_merge(struct request_queue *q, } /* - * At this point we have either done a back merge - * or front merge. We need the smaller start_time of - * the merged requests to be the current request - * for accounting purposes. + * At this point we have either done a back merge or front merge. We + * need the smaller start_time_ns of the merged requests to be the + * current request for accounting purposes. */ - if (time_after(req->start_time, next->start_time)) - req->start_time = next->start_time; + if (next->start_time_ns < req->start_time_ns) + req->start_time_ns = next->start_time_ns; req->biotail->bi_next = next->bio; req->biotail = next->biotail; diff --git a/block/blk-mq.c b/block/blk-mq.c index 39b4e9834d82..4e9d83594cca 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -309,7 +309,7 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, RB_CLEAR_NODE(&rq->rb_node); rq->rq_disk = NULL; rq->part = NULL; - rq->start_time = jiffies; + rq->start_time_ns = ktime_get_ns(); rq->io_start_time_ns = 0; rq->nr_phys_segments = 0; #if defined(CONFIG_BLK_DEV_INTEGRITY) @@ -329,8 +329,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, #ifdef CONFIG_BLK_CGROUP rq->rl = NULL; - set_start_time_ns(rq); - rq->cgroup_io_start_time_ns = 0; #endif data->ctx->rq_dispatched[op_is_sync(op)]++; @@ -506,12 +504,14 @@ EXPORT_SYMBOL_GPL(blk_mq_free_request); inline void __blk_mq_end_request(struct request *rq, blk_status_t error) { + u64 now = ktime_get_ns(); + if (rq->rq_flags & RQF_STATS) { blk_mq_poll_stats_start(rq->q); - blk_stat_add(rq); + blk_stat_add(rq, now); } - blk_account_io_done(rq); + blk_account_io_done(rq, now); if (rq->end_io) { wbt_done(rq->q->rq_wb, rq); diff --git a/block/blk-stat.c b/block/blk-stat.c index 725a881723b0..175c143ac5b9 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -47,15 +47,14 @@ static void __blk_stat_add(struct blk_rq_stat *stat, u64 value) stat->nr_samples++; } -void blk_stat_add(struct request *rq) +void blk_stat_add(struct request *rq, u64 now) { struct request_queue *q = rq->q; struct blk_stat_callback *cb; struct blk_rq_stat *stat; int bucket; - u64 now, value; + u64 value; - now = ktime_get_ns(); value = (now >= rq->io_start_time_ns) ? now - rq->io_start_time_ns : 0; blk_throtl_stat_add(rq, value); diff --git a/block/blk-stat.h b/block/blk-stat.h index 17c812db0aca..78399cdde9c9 100644 --- a/block/blk-stat.h +++ b/block/blk-stat.h @@ -65,7 +65,7 @@ struct blk_stat_callback { struct blk_queue_stats *blk_alloc_queue_stats(void); void blk_free_queue_stats(struct blk_queue_stats *); -void blk_stat_add(struct request *); +void blk_stat_add(struct request *rq, u64 now); /* record time/size info in request but not add a callback */ void blk_stat_enable_accounting(struct request_queue *q); diff --git a/block/blk.h b/block/blk.h index b034fd2460c4..eaf1a8e87d11 100644 --- a/block/blk.h +++ b/block/blk.h @@ -186,7 +186,7 @@ unsigned int blk_plug_queued_count(struct request_queue *q); void blk_account_io_start(struct request *req, bool new_io); void blk_account_io_completion(struct request *req, unsigned int bytes); -void blk_account_io_done(struct request *req); +void blk_account_io_done(struct request *req, u64 now); /* * EH timer and IO completion will both attempt to 'grab' the request, make diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 652ca064de20..6b9f6b1cd33b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -4228,8 +4228,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfqd->rq_in_driver--; cfqq->dispatched--; (RQ_CFQG(rq))->dispatched--; - cfqg_stats_update_completion(cfqq->cfqg, rq_start_time_ns(rq), - rq_io_start_time_ns(rq), rq->cmd_flags); + cfqg_stats_update_completion(cfqq->cfqg, rq->start_time_ns, + rq->io_start_time_ns, rq->cmd_flags); cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--; @@ -4245,16 +4245,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) cfqq_type(cfqq)); st->ttime.last_end_request = now; - /* - * We have to do this check in jiffies since start_time is in - * jiffies and it is not trivial to convert to ns. If - * cfq_fifo_expire[1] ever comes close to 1 jiffie, this test - * will become problematic but so far we are fine (the default - * is 128 ms). - */ - if (!time_after(rq->start_time + - nsecs_to_jiffies(cfqd->cfq_fifo_expire[1]), - jiffies)) + if (rq->start_time_ns + cfqd->cfq_fifo_expire[1] <= now) cfqd->last_delayed_sync = now; } diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index bf0b840645cc..1c18f335da04 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -406,7 +406,7 @@ static blk_status_t dm_dispatch_clone_request(struct request *clone, struct requ if (blk_queue_io_stat(clone->q)) clone->rq_flags |= RQF_IO_STAT; - clone->start_time = jiffies; + clone->start_time_ns = ktime_get_ns(); r = blk_insert_cloned_request(clone->q, clone); if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE) /* must complete clone in terms of original request */ diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9ef412666df1..e42d510daf3c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -205,7 +205,8 @@ struct request { struct gendisk *rq_disk; struct hd_struct *part; - unsigned long start_time; + /* Time that I/O was submitted to the kernel. */ + u64 start_time_ns; /* Time that I/O was submitted to the device. */ u64 io_start_time_ns; @@ -277,8 +278,6 @@ struct request { #ifdef CONFIG_BLK_CGROUP struct request_list *rl; /* rl this rq is alloced from */ - unsigned long long cgroup_start_time_ns; - unsigned long long cgroup_io_start_time_ns; /* when passed to hardware */ #endif }; @@ -1798,39 +1797,6 @@ int kblockd_schedule_work(struct work_struct *work); int kblockd_schedule_work_on(int cpu, struct work_struct *work); int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay); -#ifdef CONFIG_BLK_CGROUP -static inline void set_start_time_ns(struct request *req) -{ - req->cgroup_start_time_ns = ktime_get_ns(); -} - -static inline void set_io_start_time_ns(struct request *req) -{ - req->cgroup_io_start_time_ns = ktime_get_ns(); -} - -static inline u64 rq_start_time_ns(struct request *req) -{ - return req->cgroup_start_time_ns; -} - -static inline u64 rq_io_start_time_ns(struct request *req) -{ - return req->cgroup_io_start_time_ns; -} -#else -static inline void set_start_time_ns(struct request *req) {} -static inline void set_io_start_time_ns(struct request *req) {} -static inline u64 rq_start_time_ns(struct request *req) -{ - return 0; -} -static inline u64 rq_io_start_time_ns(struct request *req) -{ - return 0; -} -#endif - #define MODULE_ALIAS_BLOCKDEV(major,minor) \ MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor)) #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \ -- 2.30.2