mm: rename global_page_state to global_zone_page_state

global_page_state is error prone as a recent bug report pointed out [1].
It only returns proper values for zone based counters as the enum it
gets suggests.  We already have global_node_page_state so let's rename
global_page_state to global_zone_page_state to be more explicit here.
All existing users seems to be correct:

$ git grep "global_page_state(NR_" | sed 's@.*(\(NR_[A-Z_]*\)).*@\1@' | sort | uniq -c
      2 NR_BOUNCE
      2 NR_FREE_CMA_PAGES
     11 NR_FREE_PAGES
      1 NR_KERNEL_STACK_KB
      1 NR_MLOCK
      2 NR_PAGETABLE

This patch shouldn't introduce any functional change.

[1] http://lkml.kernel.org/r/201707260628.v6Q6SmaS030814@www262.sakura.ne.jp

Link: http://lkml.kernel.org/r/20170801134256.5400-2-hannes@cmpxchg.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/mm/vmstat.c b/mm/vmstat.c
index e131b51654c7..ba9b202e8500 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1502,7 +1502,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
         if (!v)
                 return ERR_PTR(-ENOMEM);
         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-                v[i] = global_page_state(i);
+                v[i] = global_zone_page_state(i);
         v += NR_VM_ZONE_STAT_ITEMS;
 
         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
@@ -1591,7 +1591,7 @@ int vmstat_refresh(struct ctl_table *table, int write,
          * which can equally be echo'ed to or cat'ted from (by root),
          * can be used to update the stats just before reading them.
          *
-         * Oh, and since global_page_state() etc. are so careful to hide
+         * Oh, and since global_zone_page_state() etc. are so careful to hide
          * transiently negative values, report an error here if any of
          * the stats is negative, so we know to go looking for imbalance.
          */