Re: [RFC][PATCH] Remove cgroup member from struct page

From: KAMEZAWA Hiroyuki
Date: Sun Aug 31 2008 - 22:34:38 EST


On Sun, 31 Aug 2008 23:17:56 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

>
> This is a rewrite of a patch I had written long back to remove struct page
> (I shared the patches with Kamezawa, but never posted them anywhere else).
> I spent the weekend, cleaning them up for 2.6.27-rc5-mmotm (29 Aug 2008).
>
> I've tested the patches on an x86_64 box, I've run a simple test running
> under the memory control group and the same test running concurrently under
> two different groups (and creating pressure within their groups). I've also
> compiled the patch with CGROUP_MEM_RES_CTLR turned off.
>
> Advantages of the patch
>
> 1. It removes the extra pointer in struct page
>
> Disadvantages
>
> 1. It adds an additional lock structure to struct page_cgroup
> 2. Radix tree lookup is not an O(1) operation, once the page is known
> getting to the page_cgroup (pc) is a little more expensive now.
>
> This is an initial RFC for comments
>
> TODOs
>
> 1. Test the page migration changes
> 2. Test the performance impact of the patch/approach
>
> Comments/Reviews?
>
BTW, how deep this radix-tree on 4GB/32GB/64GB/256GB machine ?

Thanks,
-Kame

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