diff options
| author | Vladimir Davydov <vdavydov@parallels.com> | 2013-02-14 18:19:59 +0400 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2013-02-15 16:45:07 +0100 |
| commit | 5577022f4ed8973762450ebe7fe7ebfd953817db (patch) | |
| tree | c6c965101e32bf2b36155da0fc0ad94c696d4606 /block/blk-exec.c | |
| parent | 686855f5d833178e518d79e7912cdb3268a9fa69 (diff) | |
| download | lwn-5577022f4ed8973762450ebe7fe7ebfd953817db.tar.gz lwn-5577022f4ed8973762450ebe7fe7ebfd953817db.zip | |
block: account iowait time when waiting for completion of IO request
Using wait_for_completion() for waiting for a IO request to be executed
results in wrong iowait time accounting. For example, a system having
the only task doing write() and fdatasync() on a block device can be
reported being idle instead of iowaiting as it should because
blkdev_issue_flush() calls wait_for_completion() which in turn calls
schedule() that does not increment the iowait proc counter and thus does
not turn on iowait time accounting.
The patch makes block layer use wait_for_completion_io() instead of
wait_for_completion() where appropriate to account iowait time
correctly.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-exec.c')
| -rw-r--r-- | block/blk-exec.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/block/blk-exec.c b/block/blk-exec.c index 74638ec234c8..f634de772b0c 100644 --- a/block/blk-exec.c +++ b/block/blk-exec.c @@ -120,9 +120,9 @@ int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk, /* Prevent hang_check timer from firing at us during very long I/O */ hang_check = sysctl_hung_task_timeout_secs; if (hang_check) - while (!wait_for_completion_timeout(&wait, hang_check * (HZ/2))); + while (!wait_for_completion_io_timeout(&wait, hang_check * (HZ/2))); else - wait_for_completion(&wait); + wait_for_completion_io(&wait); if (rq->errors) err = -EIO; |