global_page_state() was renamed to global_zone_page_state() by commit
c41f012ade0b ("mm: rename global_page_state to global_zone_page_state").
However, some more changes are needed (and were in fact needed even with
kernels older than 4.14.
Since commit 385386cff4c6 ("mm: vmstat: move slab statistics from zone to
node counters") in v4.13-rc1, NR_SLAB_UNRECLAIMABLE needs to be used with
global_node_page_state(), in-tree callers were fixed by commit d507e2ebd2c7
("mm: fix global NR_SLAB_.*CLAIMABLE counter reads").
Since commit 599d0c954f91 ("mm, vmscan: move LRU lists to node") in
v4.8-rc1, NR_UNEVICTABLE needs global_node_page_state() rather than
global_page_state().
Since commit 50658e2e04c1 ("mm: move page mapped accounting to the node")
in v4.8-rc1, NR_ANON_PAGES needs global_node_page_state() as well. This was
shortly before it was renamed to NR_ANON_MAPPED but as both got into
mainline in v4.8-rc1, we can do with one #ifdef.
To keep HostIF_EstimateLockedPageLimit() readable, extract the version
dependent calls into inline helpers.
Michal Kubecek