[PATCH v3 2/7] mm/lruvec: add irqsave flags into lruvec struct

[Alex Shi]

We need a irqflags vaiable to save state when do irqsave action, declare
it here would make code more clear/clean.

Rong Chen <rong.a.chen@xxxxxxxxx> reported the 'irqflags' variable need
move to the tail of lruvec struct otherwise it causes 18% regressions of
vm-scalability testing on his machine. So add the flags and lru_lock to
both near struct tail, even I have no clue of this perf losing.

Originally-from: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Arun KS <arunks@xxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
CC: Rong Chen <rong.a.chen@xxxxxxxxx>
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 include/linux/mmzone.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a13b8a602ee5..9b8b8daf4e03 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -269,6 +269,8 @@ struct lruvec {
 	unsigned long			flags;
 	/* per lruvec lru_lock for memcg */
 	spinlock_t			lru_lock;
+	/* flags for irqsave */
+	unsigned long			irqflags;
 #ifdef CONFIG_MEMCG
 	struct pglist_data *pgdat;
 #endif
-- 
1.8.3.1