Subject: Re: [RFC][2/3] Account and control virtual address space
	allocations
From: Dave Hansen <haveblue@us.ibm.com>
To: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: linux-mm@kvack.org, Hugh Dickins <hugh@veritas.com>,
       Sudhir Kumar <skumar@linux.vnet.ibm.com>,
       YAMAMOTO Takashi <yamamoto@valinux.co.jp>,
       Paul Menage <menage@google.com>, lizf@cn.fujitsu.com,
       linux-kernel@vger.kernel.org, taka@valinux.co.jp,
       David Rientjes <rientjes@google.com>,
       Pavel Emelianov <xemul@openvz.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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Date: Mon, 17 Mar 2008 09:53:10 -0700
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On Sun, 2008-03-16 at 23:00 +0530, Balbir Singh wrote:
> @@ -787,6 +788,8 @@ static int ptrace_bts_realloc(struct tas
>         current->mm->total_vm  -= old_size;
>         current->mm->locked_vm -= old_size;
>  
> +       mem_cgroup_update_as(current->mm, -old_size);
> +
>         if (size == 0)
>                 goto out;

I think splattering these things all over is probably a bad idea.

If you're going to do this, I think you need a couple of phases.  

1. update the vm_(un)acct_memory() functions to take an mm
2. start using them (or some other abstracted functions in place)
3. update the new functions for cgroups

It's a bit non-obvious why you do the mem_cgroup_update_as() calls in
the places that you do from context.

Having some other vm-abstracted functions will also keep you from
splattering mem_cgroup_update_as() across the tree.  That's a pretty bad
name. :)  ...update_mapped() or ...update_vm() might be a wee bit
better. 

-- Dave

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