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Commit d72d904a5367ad4ca3f2c9a2ce8c3a68f0b28bf0

Authored by Jens Axboe
1 parent d83c671fb7
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

[BLOCK] Update read/write block io statistics at completion time 

Right now we do it at queueing time, which works alright for reads
(since they are usually sync), but not for async writes since we can
queue io a lot faster than we can complete it. This makes the vmstat
output look extremely bursty.

Signed-off-by: Jens Axboe <axboe@suse.de>

Showing 1 changed file with 11 additions and 8 deletions Side-by-side Diff

drivers/block/ll_rw_blk.c
Diff comments   View file @ d72d904
... ... @@ -2387,16 +2387,12 @@
2387 2387 if (!blk_fs_request(rq) || !rq->rq_disk)
2388 2388 return;
2389 2389  
2390   - if (rw == READ) {
2391   - __disk_stat_add(rq->rq_disk, read_sectors, nr_sectors);
2392   - if (!new_io)
  2390 + if (!new_io) {
  2391 + if (rw == READ)
2393 2392 __disk_stat_inc(rq->rq_disk, read_merges);
2394   - } else if (rw == WRITE) {
2395   - __disk_stat_add(rq->rq_disk, write_sectors, nr_sectors);
2396   - if (!new_io)
  2393 + else
2397 2394 __disk_stat_inc(rq->rq_disk, write_merges);
2398   - }
2399   - if (new_io) {
  2395 + } else {
2400 2396 disk_round_stats(rq->rq_disk);
2401 2397 rq->rq_disk->in_flight++;
2402 2398 }
... ... @@ -3046,6 +3042,13 @@
3046 3042 printk("end_request: I/O error, dev %s, sector %llu\n",
3047 3043 req->rq_disk ? req->rq_disk->disk_name : "?",
3048 3044 (unsigned long long)req->sector);
  3045 + }
  3046 +
  3047 + if (blk_fs_request(req) && req->rq_disk) {
  3048 + if (rq_data_dir(req) == READ)
  3049 + __disk_stat_add(req->rq_disk, read_sectors, nr_bytes >> 9);
  3050 + else
  3051 + __disk_stat_add(req->rq_disk, write_sectors, nr_bytes >> 9);
3049 3052 }
3050 3053  
3051 3054 total_bytes = bio_nbytes = 0;