Re: [PATCH v2] mm: exclude isolated non-lru pages from NR_ISOLATED_ANON or NR_ISOLATED_FILE.

From: Michal Hocko
Date: Fri Oct 14 2016 - 09:53:54 EST

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