[Devel] Re: [PATCH 9/13] BC: locked pages (charge hooks)

[Pavel Emelianov]

Nick Piggin wrote:
> Kirill Korotaev wrote:
>
>> Introduce calls to BC core over the kernel to charge locked memory.
>>
>> Normaly new locked piece of memory may appear in insert_vm_struct,
>> but there are places (do_mmap_pgoff, dup_mmap etc) when new vma
>> is not inserted by insert_vm_struct(), but either link_vma-ed or
>> merged with some other - these places call BC code explicitly.
>>
>> Plus sys_mlock[all] itself has to be patched to charge/uncharge
>> needed amount of pages.
>
>
> I still haven't heard your good reasons why such a complex scheme is
> required when my really simple proposal of unconditionally charging
> the page to the container it was allocated by.
Charging the page to the container it was allocated in is a possible and
correct way, we agree, but how does this comment refer to locked pages
accounting?
>
> That has the benefit of not being full of user explotable holes and
> also not putting such a huge burden on mm/ and the wider kernel in
> general.