[PATCH 4.9 61/72] mm: rmap: fix huge file mmap accounting in the memcg stats

Greg Kroah-Hartman
2017-04-06T09:14:19Z

From: Johannes Weiner <hannes@cmpxchg.org>

commit 553af430e7c981e6e8fa5007c5b7b5773acc63dd upstream.

Huge pages are accounted as single units in the memcg's "file_mapped"
counter. Account the correct number of base pages, like we do in the
corresponding node counter.

Link: http://lkml.kernel.org/r/20170322005111.3156-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/memcontrol.h | 6 ++++++
mm/rmap.c | 4 ++--
2 files changed, 8 insertions(+), 2 deletions(-)

--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -739,6 +739,12 @@ static inline bool mem_cgroup_oom_synchr
return false;
}

+static inline void mem_cgroup_update_page_stat(struct page *page,
+ enum mem_cgroup_stat_index idx,
+ int nr)
+{
+}
+
static inline void mem_cgroup_inc_page_stat(struct page *page,
enum mem_cgroup_stat_index idx)
{
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1295,7 +1295,7 @@ void page_add_file_rmap(struct page *pag
goto out;
}
__mod_node_page_state(page_pgdat(page), NR_FILE_MAPPED, nr);
- mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
+ mem_cgroup_update_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, nr);
out:
unlock_page_memcg(page);
}
@@ -1335,7 +1335,7 @@ static void page_remove_file_rmap(struct
* pte lock(a spinlock) is held, which implies preemption disabled.
*/
__mod_node_page_state(page_pgdat(page), NR_FILE_MAPPED, -nr);
- mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED);
+ mem_cgroup_update_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, -nr);

if (unlikely(PageMlocked(page)))
clear_page_mlock(page);