Re: [PATCH 1/12] memcg avoid accounting special mappings not on LRU

[Balbir Singh]

KAMEZAWA Hiroyuki wrote:
> On Fri, 26 Sep 2008 13:55:54 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
> 
>> KAMEZAWA Hiroyuki wrote:
>>> There are not-on-LRU pages which can be mapped and they are not worth to
>>> be accounted. (becasue we can't shrink them and need dirty codes to handle
>>> specical case) We'd like to make use of usual objrmap/radix-tree's protcol
>>> and don't want to account out-of-vm's control pages.
>>>
>>> When special_mapping_fault() is called, page->mapping is tend to be NULL 
>>> and it's charged as Anonymous page.
>>> insert_page() also handles some special pages from drivers.
>>>
>>> This patch is for avoiding to account special pages.
>>>
>> Hmm... I am a little concerned that with these changes actual usage will much
>> more than what we report in memory.usage_in_bytes. Why not move them to
>> non-reclaimable LRU list as unevictable pages (once those patches go in, we can
>> push this as well). 
> 
> Because they are not on LRU ...i.e. !PageLRU(page)
> 

I understand.. Thanks for clarifying.. my concern is w.r.t accounting, we
account it in RSS (file RSS).

-- 
	Balbir
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