Re: [PATCH 2/2] mm/memcontrol.c: introduce helper mem_cgroup_zoneinfo_zone()

On Fri, 2 May 2014 19:29:08 -0400 Johannes Weiner [off-list ref] wrote:

Memcg zoneinfo lookup sites have either the page, the zone, or the
node id and zone index, but sites that only have the zone have to look
up the node id and zone index themselves, whereas sites that already
have those two integers use a function for a simple pointer chase.

Provide mem_cgroup_zone_zoneinfo() that takes a zone pointer and let
sites that already have node id and zone index - all for each node,
for each zone iterators - use &memcg->nodeinfo[nid]->zoneinfo[zid].

Rename page_cgroup_zoneinfo() to mem_cgroup_page_zoneinfo() to match.

Patch shrinks my mm/memcontrol.o nicely:

   text    data     bss     dec     hex filename
  55702   15681   24560   95943   176c7 mm/memcontrol.o-before
  55489   15681   24464   95634   17592 mm/memcontrol.o-after

The bss size changes are weird - the patch doesn't touch bss afaict. 
This often happens.  One day I'll get in there and work out why.