On Wed, 2 Mar 2011 08:10:35 +0900
Minchan Kim [off-list ref] wrote:

On Wed, Mar 2, 2011 at 7:39 AM, Andrea Arcangeli [off-list ref] wrote:

quoted

On Wed, Mar 02, 2011 at 07:33:13AM +0900, Minchan Kim wrote:

quoted

Sorry for bothering you but I think you get the data.
It helps someone in future very much to know why we determined to
remove the feature at that time and they should do what kinds of
experiment to prove it has a benefit to add compaction in kswapd
again.

This is a benchmark I'm unsure if it's ok to publish results but it
should be possible to simulate it with a device driver.

Arthur provided kswapd load usage data too, so I hope that's enough.

My other patch (compaction-kswapd-3) is way better than current logic
and retains compaction in kswapd. That shows slightly higher
kswapd utilization with Arthur's multimedia workload, and a bit worse
performance on the network benchmark. So I thought it was better to go
with the fastest potion as long as we don't have a logic that uses
compaction and shows improved performance and lower latency than with
no compaction at all in kswapd.

I didn't notice Arthur's problem.
The patch seems to fix a real problem so I think it's enough.
I wished you wrote down the link url about Arthur on LKML.

You can remove compact_mode of compact_control.
Otherwise, looks good to me.

I'd be pretty worried about jamming this into 2.6.38 at this late
stage.  And some vague talk about something Arthur did really doesn't
help a lot!  It would be better to have some good, solid quantitative
justification for what is really an emergency patch.  

Bear in mind that we always have a middle option: merge a patch into
2.6.39-rc1 and tag it for backporting into 2.6.38.x.  That gives us
more time to test it and to generally give it a shakedown.  But to make
decisions like that and to commend a patch to the -stable maintainers,
we need to provide better information please.

Also, "This goes on top of the two lowlatency fixes for compaction"
isn't particularly helpful.  I need to verify that the referred-to
patches are already in mainline but I don't have a clue what this
description refers to.  More specificity, please - it helps avoid
mistakes.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>