2009-10-07 09:00:52

by Corrado Zoccolo

Subject: [PATCH] cfq-iosched: fix think time allowed for seekers

CFQ enables idle only for processes that think less than the allowed
idle time. Since idle time is lower for seeky queues, we should use the
correct value in the comparison.

Signed-off-by: Corrado Zoccolo <[email protected]>
---
block/cfq-iosched.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 55bb8ca..4c795a2 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1997,7 +1997,10 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
(!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
- if (cic->ttime_mean > cfqd->cfq_slice_idle)
+ unsigned int slice_idle = cfqd->cfq_slice_idle;
+ if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
+ slice_idle = msecs_to_jiffies(CFQ_MIN_TT);
+ if (cic->ttime_mean > slice_idle)
enable_idle = 0;
else
enable_idle = 1;
--
1.6.2.5

2009-10-07 17:49:30

by Jens Axboe

Subject: Re: [PATCH] cfq-iosched: fix think time allowed for seekers

On Wed, Oct 07 2009, Corrado Zoccolo wrote:
> CFQ enables idle only for processes that think less than the allowed
> idle time. Since idle time is lower for seeky queues, we should use the
> correct value in the comparison.

Looks good, applied. Thanks!

--
Jens Axboe