3 files changed, 20 insertions, 25 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a9e3b76aa884..25b9ca93d232 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -56,7 +56,7 @@ extern void mem_cgroup_move_lists(struct page *page,
                                   enum lru_list from, enum lru_list to);
 extern void mem_cgroup_uncharge_page(struct page *page);
 extern void mem_cgroup_uncharge_cache_page(struct page *page);
-extern int mem_cgroup_shrink_usage(struct page *page,
+extern int mem_cgroup_shmem_charge_fallback(struct page *page,
                         struct mm_struct *mm, gfp_t gfp_mask);
 
 extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
@@ -155,7 +155,7 @@ static inline void mem_cgroup_uncharge_cache_page(struct page *page)
 {
 }
 
-static inline int mem_cgroup_shrink_usage(struct page *page,
+static inline int mem_cgroup_shmem_charge_fallback(struct page *page,
                         struct mm_struct *mm, gfp_t gfp_mask)
 {
         return 0;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 575203ae2109..01c2d8f14685 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1617,37 +1617,28 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem,
 }
 
 /*
- * A call to try to shrink memory usage under specified resource controller.
- * This is typically used for page reclaiming for shmem for reducing side
- * effect of page allocation from shmem, which is used by some mem_cgroup.
+ * A call to try to shrink memory usage on charge failure at shmem's swapin.
+ * Calling hierarchical_reclaim is not enough because we should update
+ * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
+ * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
+ * not from the memcg which this page would be charged to.
+ * try_charge_swapin does all of these works properly.
  */
-int mem_cgroup_shrink_usage(struct page *page,
+int mem_cgroup_shmem_charge_fallback(struct page *page,
                             struct mm_struct *mm,
                             gfp_t gfp_mask)
 {
         struct mem_cgroup *mem = NULL;
-        int progress = 0;
-        int retry = MEM_CGROUP_RECLAIM_RETRIES;
+        int ret;
 
         if (mem_cgroup_disabled())
                 return 0;
-        if (page)
-                mem = try_get_mem_cgroup_from_swapcache(page);
-        if (!mem && mm)
-                mem = try_get_mem_cgroup_from_mm(mm);
-        if (unlikely(!mem))
-                return 0;
 
-        do {
-                progress = mem_cgroup_hierarchical_reclaim(mem,
-                                        gfp_mask, true, false);
-                progress += mem_cgroup_check_under_limit(mem);
-        } while (!progress && --retry);
+        ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+        if (!ret)
+                mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
 
-        css_put(&mem->css);
-        if (!retry)
-                return -ENOMEM;
-        return 0;
+        return ret;
 }
 
 static DEFINE_MUTEX(set_limit_mutex);
diff --git a/mm/shmem.c b/mm/shmem.c
index f9cb20ebb990..b25f95ce3db7 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1340,8 +1340,12 @@ repeat:
                         shmem_swp_unmap(entry);
                         spin_unlock(&info->lock);
                         if (error == -ENOMEM) {
-                                /* allow reclaim from this memory cgroup */
-                                error = mem_cgroup_shrink_usage(swappage,
+                                /*
+                                 * reclaim from proper memory cgroup and
+                                 * call memcg's OOM if needed.
+                                 */
+                                error = mem_cgroup_shmem_charge_fallback(
+                                                                swappage,
                                                                 current->mm,
                                                                 gfp);
                                 if (error) {