[PATCH] fixup: vmscan: Fix build on !CONFIG_MEMCG from nr_deactivate changes

[Chris Down]

"mm: move nr_deactivate accounting to shrink_active_list()" uses the
non-irqsaved version of count_memcg_events (__count_memcg_events), but
we've only exported the irqsaving version of it to userspace, so the
build breaks:

    mm/vmscan.c: In function âshrink_active_listâ:
    mm/vmscan.c:2101:2: error: implicit declaration of function â__count_memcg_eventsâ; did you mean âcount_memcg_eventsâ? [-Werror=implicit-function-declaration]

This fixup makes it build with !CONFIG_MEMCG.

Signed-off-by: Chris Down <chris@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: cgroups@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: kernel-team@xxxxxx
---
 include/linux/memcontrol.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 534267947664..b226c4bafc93 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1147,6 +1147,12 @@ static inline void count_memcg_events(struct mem_cgroup *memcg,
 {
 }
 
+static inline void __count_memcg_events(struct mem_cgroup *memcg,
+					enum vm_event_item idx,
+					unsigned long count)
+{
+}
+
 static inline void count_memcg_page_event(struct page *page,
 					  int idx)
 {
-- 
2.21.0