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Date: Fri, 18 Aug 2006 14:54:29 +0400
From: Kirill Korotaev <dev@sw.ru>
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To: Andi Kleen <ak@suse.de>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>, Dave Hansen <haveblue@us.ibm.com>,
       rohitseth@google.com, Rik van Riel <riel@redhat.com>,
       ckrm-tech@lists.sourceforge.net,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Christoph Hellwig <hch@infradead.org>, Andrey Savochkin <saw@sw.ru>,
       devel@openvz.org, hugh@veritas.com, Ingo Molnar <mingo@elte.hu>,
       Pavel Emelianov <xemul@openvz.org>
Subject: Re: [ckrm-tech] [RFC][PATCH 5/7] UBC: kernel memory accounting (core)
References: <44E33893.6020700@sw.ru> <1155824788.9274.32.camel@localhost.localdomain> <1155826917.15195.101.camel@localhost.localdomain> <200608171804.41433.ak@suse.de>
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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.

Thanks,
Kirill