[PATCH] mm/vmstat: avoid taking zone lock in /proc/buddyinfo reads

[Imran Khan]

frag_show_print() just reads zone->free_area[order].nr_free, so
it can safely do this without needing the zone->lock.

Pass nolock=true from frag_show(), so that walk_zones_in_node()
can skip the zone->lock acquisition.

Signed-off-by: Imran Khan <imran.f.khan@xxxxxxxxxx>
---
 mm/vmstat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmstat.c b/mm/vmstat.c
index f534972f517de..7b93fbf9af092 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1568,7 +1568,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 static int frag_show(struct seq_file *m, void *arg)
 {
 	pg_data_t *pgdat = (pg_data_t *)arg;
-	walk_zones_in_node(m, pgdat, true, false, frag_show_print);
+	walk_zones_in_node(m, pgdat, true, true, frag_show_print);
 	return 0;
 }
 

base-commit: e43ffb69e0438cddd72aaa30898b4dc446f664f8
-- 
2.34.1