From 6f74e5402d4c7f1073f6f18f5d46939f01f3d0a3 Mon Sep 17 00:00:00 2001
From: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Date: Thu, 30 Apr 2009 15:08:19 -0700
Subject: [PATCH] --- yaml --- r: 144364 b: refs/heads/master c:
 ae3abae64f177586be55b04a7fb7047a34b21a3e h: refs/heads/master v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/memcontrol.h |  4 ++--
 trunk/mm/memcontrol.c            | 33 ++++++++++++--------------------
 trunk/mm/shmem.c                 |  8 ++++++--
 4 files changed, 21 insertions(+), 26 deletions(-)

diff --git a/[refs] b/[refs]
index 85dd52c3f664..e7bc6e717e5e 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0816178638c15ce5472d39d771a96860dff4141a
+refs/heads/master: ae3abae64f177586be55b04a7fb7047a34b21a3e
diff --git a/trunk/include/linux/memcontrol.h b/trunk/include/linux/memcontrol.h
index a9e3b76aa884..25b9ca93d232 100644
--- a/trunk/include/linux/memcontrol.h
+++ b/trunk/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/trunk/mm/memcontrol.c b/trunk/mm/memcontrol.c
index 575203ae2109..01c2d8f14685 100644
--- a/trunk/mm/memcontrol.c
+++ b/trunk/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/trunk/mm/shmem.c b/trunk/mm/shmem.c
index f9cb20ebb990..b25f95ce3db7 100644
--- a/trunk/mm/shmem.c
+++ b/trunk/mm/shmem.c
@@ -1340,8 +1340,12 @@ static int shmem_getpage(struct inode *inode, unsigned long idx,
 			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) {