From 42dad7647aec49b3ad20dd0cb832b232a6ae514f Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Wed, 22 Apr 2009 14:01:49 +0200 Subject: block: simplify I/O stat accounting This simplifies I/O stat accounting switching code and separates it completely from I/O scheduler switch code. Requests are accounted according to the state of their request queue at the time of the request allocation. There is no need anymore to flush the request queue when switching I/O accounting state. Signed-off-by: Jerome Marchand Signed-off-by: Jens Axboe --- block/blk-core.c | 6 ++++-- block/blk-merge.c | 5 ++++- block/blk-sysfs.c | 4 ---- block/blk.h | 7 +------ 4 files changed, 9 insertions(+), 13 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 07ab75403e1..2998fe3a237 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -643,7 +643,7 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq) } static struct request * -blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) +blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask) { struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask); @@ -652,7 +652,7 @@ blk_alloc_request(struct request_queue *q, int rw, int priv, gfp_t gfp_mask) blk_rq_init(q, rq); - rq->cmd_flags = rw | REQ_ALLOCED; + rq->cmd_flags = flags | REQ_ALLOCED; if (priv) { if (unlikely(elv_set_request(q, rq, gfp_mask))) { @@ -792,6 +792,8 @@ static struct request *get_request(struct request_queue *q, int rw_flags, if (priv) rl->elvpriv++; + if (blk_queue_io_stat(q)) + rw_flags |= REQ_IO_STAT; spin_unlock_irq(q->queue_lock); rq = blk_alloc_request(q, rw_flags, priv, gfp_mask); diff --git a/block/blk-merge.c b/block/blk-merge.c index 63760ca3da0..23d2a6fe34a 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -402,7 +402,10 @@ static int attempt_merge(struct request_queue *q, struct request *req, elv_merge_requests(q, req, next); - blk_account_io_merge(req); + /* + * 'next' is going away, so update stats accordingly + */ + blk_account_io_merge(next); req->ioprio = ioprio_best(req->ioprio, next->ioprio); if (blk_rq_cpu_valid(next)) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index cac4e9febe6..3ff9bba3379 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -209,14 +209,10 @@ static ssize_t queue_iostats_store(struct request_queue *q, const char *page, ssize_t ret = queue_var_store(&stats, page, count); spin_lock_irq(q->queue_lock); - elv_quiesce_start(q); - if (stats) queue_flag_set(QUEUE_FLAG_IO_STAT, q); else queue_flag_clear(QUEUE_FLAG_IO_STAT, q); - - elv_quiesce_end(q); spin_unlock_irq(q->queue_lock); return ret; diff --git a/block/blk.h b/block/blk.h index 5dfc41267a0..79c85f7c9ff 100644 --- a/block/blk.h +++ b/block/blk.h @@ -114,12 +114,7 @@ static inline int blk_cpu_to_group(int cpu) static inline int blk_do_io_stat(struct request *rq) { - struct gendisk *disk = rq->rq_disk; - - if (!disk || !disk->queue) - return 0; - - return blk_queue_io_stat(disk->queue) && (rq->cmd_flags & REQ_ELVPRIV); + return rq->rq_disk && blk_rq_io_stat(rq); } #endif -- cgit v1.2.3