From 28f13702f03e527fcb979747a882cf366c489c50 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 7 May 2008 10:15:46 +0200 Subject: block: avoid duplicate calls to get_part() in disk stat code get_part() is fairly expensive, as it O(N) loops over partitions to find the right one. In lots of normal IO paths we end up looking up the partition twice, to make matters even worse. Change the stat add code to accept a passed in partition instead. Signed-off-by: Jens Axboe --- block/blk-core.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 1b7dddf94f4f..2987fe47b5ee 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -54,15 +54,16 @@ static DEFINE_PER_CPU(struct list_head, blk_cpu_done); static void drive_stat_acct(struct request *rq, int new_io) { + struct hd_struct *part; int rw = rq_data_dir(rq); if (!blk_fs_request(rq) || !rq->rq_disk) return; - if (!new_io) { - __all_stat_inc(rq->rq_disk, merges[rw], rq->sector); - } else { - struct hd_struct *part = get_part(rq->rq_disk, rq->sector); + part = get_part(rq->rq_disk, rq->sector); + if (!new_io) + __all_stat_inc(rq->rq_disk, part, merges[rw], rq->sector); + else { disk_round_stats(rq->rq_disk); rq->rq_disk->in_flight++; if (part) { @@ -1538,10 +1539,11 @@ static int __end_that_request_first(struct request *req, int error, } if (blk_fs_request(req) && req->rq_disk) { + struct hd_struct *part = get_part(req->rq_disk, req->sector); const int rw = rq_data_dir(req); - all_stat_add(req->rq_disk, sectors[rw], - nr_bytes >> 9, req->sector); + all_stat_add(req->rq_disk, part, sectors[rw], + nr_bytes >> 9, req->sector); } total_bytes = bio_nbytes = 0; @@ -1727,8 +1729,8 @@ static void end_that_request_last(struct request *req, int error) const int rw = rq_data_dir(req); struct hd_struct *part = get_part(disk, req->sector); - __all_stat_inc(disk, ios[rw], req->sector); - __all_stat_add(disk, ticks[rw], duration, req->sector); + __all_stat_inc(disk, part, ios[rw], req->sector); + __all_stat_add(disk, part, ticks[rw], duration, req->sector); disk_round_stats(disk); disk->in_flight--; if (part) { -- cgit v1.2.3