Re: kernel building regression on 32-rc5 kernel

From: Jens Axboe
Date: Tue Nov 03 2009 - 13:32:41 EST


On Tue, Nov 03 2009, Shi, Alex wrote:
> I found the kernel building will have about 20%~ 30% regressions on
> our NHM machines. My kernel build do the following things 15 times:
>
> make mrproper; echo \"3\">/proc/sys/vm/drop_caches; make defconfig;
> make -j${2timescpunumbers}
>
>
>
> Bisect found it is due to the commitment:
>
> commit a6151c3a5c8e1ff5a28450bc8d6a99a2a0add0a7

I looked over that commit and found one typo, can you check with this
patch applied?

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 069a610..5802e32 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2051,7 +2051,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
* it's a metadata request and the current queue is doing regular IO.
*/
if (rq_is_meta(rq) && !cfqq->meta_pending)
- return false;
+ return true;

/*
* Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.

--
Jens Axboe

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