Date: Fri, 14 Oct 2016 15:53:34 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Ming Ling <ming.ling@spreadtrum.com>, akpm@linux-foundation.org,
        mgorman@techsingularity.net, vbabka@suse.cz, hannes@cmpxchg.org,
        baiyaowei@cmss.chinamobile.com, iamjoonsoo.kim@lge.com,
        rientjes@google.com, hughd@google.com, kirill.shutemov@linux.intel.com,
        riel@redhat.com, mgorman@suse.de, aquini@redhat.com, corbet@lwn.net,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        orson.zhai@spreadtrum.com, geng.ren@spreadtrum.com,
        chunyan.zhang@spreadtrum.com, zhizhou.tian@spreadtrum.com,
        yuming.han@spreadtrum.com, xiajing@spreadst.com
Subject: Re: [PATCH v2] mm: exclude isolated non-lru pages from
 NR_ISOLATED_ANON or NR_ISOLATED_FILE.
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On Fri 14-10-16 22:46:04, Minchan Kim wrote:
[...]
> > > > Why don't you simply mimic what shrink_inactive_list does? Aka count the
> > > > number of isolated pages and then account them when appropriate?
> > > >
> > > I think i am correcting clearly wrong part. So, there is no need to
> > > describe it too detailed. It's a misunderstanding, and i will add
> > > more comments as you suggest.
> > 
> > OK, so could you explain why you prefer to relyon __PageMovable rather
> > than do a trivial counting during the isolation?
> 
> I don't get it. Could you elaborate it a bit more?

It is really simple. You can count the number of file and anonymous
pages while they are isolated and then account them to NR_ISOLATED_*
later. Basically the same thing we do during the reclaim. We absolutely
do not have to rely on __PageMovable and make this code more complex
than necessary.
-- 
Michal Hocko
SUSE Labs