Re: [ckrm-tech] [RFC][PATCH 5/7] UBC: kernel memory accounting (core)

From: Kirill Korotaev
Date: Fri Aug 18 2006 - 06:49:30 EST

Andi Kleen wrote:
I don't see any good way around that. For the page struct it is a
material issue, for the others its not a big deal providing we avoid
accounting dumb stuff like dentries.

At the VM summit Linus suggested one option for user page allocation
tracking would be to track not per page but by block of pages (say the
2MB chunks) and hand those out per container. That would really need the
defrag work though.

One could always use a second set of arrays, mirroring mem_map
which one do you prefer:
- having a pointer on the struct page?
kernels without resource accounting won't have this.

- having a mirroring mem_map?
on i686 it is easy, but not sure about sparse mem
or numa configurations.
advantage: run-time configurable on boot time.
disadvantage: much lower performance with accounting.

- address_space/anon_vma can be replaced with some kind of proxy object
with 2 pointers - address_space and ub. however I don't see how it is
better then a single ptr on page.


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