Re: [00/17] Large Blocksize Support V3

Nick Piggin
2007-04-26T07:22:24Z

Christoph Lameter wrote:
> On Thu, 26 Apr 2007, Nick Piggin wrote:
>
>
>>>Right and we need to create series of other approaches that we then label
>>>"non-hack" to replace it.
>>
>>I don't understand? We're talking about several utterly different designs
>>to approach these problems. You don't agree that one might be better than
>>another?
>
>
> What I seeing is a series of approaches being put into the kernel to
> address this issue. We already have the lumpy reclaim there. Then we talk
> about other fixed to basic page handling in the kernel to make it better.
> Now you want yet another fs layer. All of that could be taken care of by

No I don't want to add another fs layer.

> a defrag approach with larger pages. This has been done a number of times
> before and actually the large page approach is a textbook example on how
> to improve performance. It goes waaaay back.

I still don't think anti fragmentation or defragmentation are a good
approach, when you consider the alternatives.

It is like Linus on the page colouring issue. That goes back a looong
way too, but that doesn't mean it is the right way to do it.

>>>The code paths can stay the same. You can switch CONFIG_LARGE pages off
>>>if you do not want it and it is as it was.
>>
>>That isn't a good reason to merge something. If you don't have numbers then
>>that just seems incredible.
>
>
> Dont worry you will get numbers... Just did not have time to fix the bug
> in this one since I had to take care of something else.

OK, I would like to see them. And also discussions of things like why
we shouldn't increase PAGE_SIZE instead.

--
SUSE Labs, Novell Inc.