Re: [PATCH 16/27] mm: Move page mapped accounting to the node

[Andrew Morton]

On Tue, 21 Jun 2016 15:15:55 +0100 Mel Gorman <mgor...@techsingularity.net> 
wrote:

> Reclaim makes decisions based on the number of pages that are mapped
> but it's mixing node and zone information. Account NR_FILE_MAPPED and
> NR_ANON_PAGES pages on the node.

<wading through rejects>

Boy, the difference between

        __mod_zone_page_state(page_zone(page), ...

and

        __mod_node_page_state(page_pgdat(page), ...

is looking subtle.  When and why to use one versus the other.  I'm not
seeing any explanation of this in there but haven't yet looked hard.