Re: Re: [PATCH 9/13] memcg: lookup page cgroup (and remove pointer from struct page)

Peter Zijlstra
2008-09-22T16:06:31Z

On Tue, 2008-09-23 at 01:04 +0900, kamezawa.hiroyu@jp.fujitsu.com wrote:
> ----- Original Message -----
> >On Mon, 2008-09-22 at 20:12 +0900, KAMEZAWA Hiroyuki wrote:
> >
> >> - all page_cgroup struct is maintained by hash.
> >> I think we have 2 ways to handle sparse index in general
> >> ...radix-tree and hash. This uses hash because radix-tree's layout is
> >> affected by memory map's layout.
> >
> >Could you provide further detail? That is, is this solely because our
> >radix tree implementation is sucky for large indexes?
> >
> no, sparse-large index.
>
> >If so, I did most of the work of fixing that, just need to spend a
> >little more time to stabalize the code.
> >
>
> IIUC, radix tree's height is determined by how sparse the space is.

Right, so Yes. Its that which I fixed.

> Then, steps to reach entries is tend to be larger than hash.
> I'm sorry if I misunderstood.

No problems,. I'll try and brush up that radix tree code and post
sometime soon.