Re: [patch 7/8] vmscan: memcg-aware unevictable page rescue scanner

Hiroyuki Kamezawa
2011-06-02T22:01:37Z

2011/6/3 Ying Han <yinghan@google.com>:
> On Thu, Jun 2, 2011 at 6:27 AM, Hiroyuki Kamezawa
> <kamezawa.hiroyuki@gmail.com> wrote:
>> 2011/6/1 Johannes Weiner <hannes@cmpxchg.org>:
>>> Once the per-memcg lru lists are exclusive, the unevictable page
>>> rescue scanner can no longer work on the global zone lru lists.
>>>
>>> This converts it to go through all memcgs and scan their respective
>>> unevictable lists instead.
>>>
>>> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
>>
>> Hm, isn't it better to have only one GLOBAL LRU for unevictable pages ?
>> memcg only needs counter for unevictable pages and LRU is not necessary
>> to be per memcg because we don't reclaim it...
>
> Hmm. Are we suggesting to keep one un-evictable LRU list for all
> memcgs? So we will have
> exclusive lru only for file and anon. If so, we are not done to make
> all the lru list being exclusive
> which is critical later to improve the zone->lru_lock contention
> across the memcgs
>
considering lrulock, yes, maybe you're right.

> Sorry If i misinterpret the suggestion here
>

My concern is I don't know for what purpose this function is used ..

Thanks,
-Kame