[PATCH] mm/page_alloc: Split per cpu page lists and zone stats -fix

[Mel Gorman <mgorman@techsingularity.net>]

mm/ is not W=1 clean for allnoconfig but the patch "mm/page_alloc: Split
per cpu page lists and zone stats" makes it worse with the following
warning

  mm/vmstat.c: In function ‘zoneinfo_show_print’:
  mm/vmstat.c:1698:28: warning: variable ‘pzstats’ set but not used [-Wunused-but-set-variable]
     struct per_cpu_zonestat *pzstats;
                              ^~~~~~~

This is a fix to the mmotm patch
mm-page_alloc-split-per-cpu-page-lists-and-zone-stats.patch.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
 mm/vmstat.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index e3bcd317ea55..a2c3f58253be 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1695,10 +1695,9 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 	seq_printf(m, "\n  pagesets");
 	for_each_online_cpu(i) {
 		struct per_cpu_pages *pcp;
-		struct per_cpu_zonestat *pzstats;
+		struct per_cpu_zonestat __maybe_unused *pzstats;
 
 		pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
-		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
 		seq_printf(m,
 			   "\n    cpu: %i"
 			   "\n              count: %i"
@@ -1709,6 +1708,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 			   pcp->high,
 			   pcp->batch);
 #ifdef CONFIG_SMP
+		pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
 		seq_printf(m, "\n  vm stats threshold: %d",
 				pzstats->stat_threshold);
 #endif