Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

[PATCH] cfq-iosched: check busy queues before deciding we are idle

Browse source 
For just one busy queue (like async write out), we often overlooked
that we could queue more io and decided we were idle instead. This causes
us quite a bit of performance loss.

Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
Jens Axboe 2006-06-01 10:07:26 +02:00
parent ba8f5baba7
commit e0de0206a2
1 changed files with 7 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
block/cfq-iosched.c
View file

@ -878,6 +878,13 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
cfqq = list_entry_cfqq(cfqd->cur_rr.next);
/*
* If no new queues are available, check if the busy list has some
* before falling back to idle io.
*/
if (!cfqq && !list_empty(&cfqd->busy_rr))
cfqq = list_entry_cfqq(cfqd->busy_rr.next);
/*
* if we have idle queues and no rt or be queues had pending
* requests, either allow immediate service if the grace period