memcg: Revert "memcg: add memory.vmscan_stat"

Revert the post-3.0 commit 82f9d486e59f5 ("memcg: add
memory.vmscan_stat").

The implementation of per-memcg reclaim statistics violates how memcg
hierarchies usually behave: hierarchically.

The reclaim statistics are accounted to child memcgs and the parent
hitting the limit, but not to hierarchy levels in between.  Usually,
hierarchical statistics are perfectly recursive, with each level
representing the sum of itself and all its children.

Since this exports statistics to userspace, this may lead to confusion
and problems with changing things after the release, so revert it now,
we can try again later.

Signed-off-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 14d62490922e..c71f84bb62ec 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -252,6 +252,12 @@ static inline void lru_cache_add_file(struct page *page)
 extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
                                         gfp_t gfp_mask, nodemask_t *mask);
 extern int __isolate_lru_page(struct page *page, int mode, int file);
+extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
+                                                  gfp_t gfp_mask, bool noswap);
+extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+                                                gfp_t gfp_mask, bool noswap,
+                                                struct zone *zone,
+                                                unsigned long *nr_scanned);
 extern unsigned long shrink_all_memory(unsigned long nr_pages);
 extern int vm_swappiness;
 extern int remove_mapping(struct address_space *mapping, struct page *page);