[PATCH 3/9] mm: list_lru: rename memcg_drain_all_list_lrus to memcg_reparent_list_lrus

[Muchun Song <songmuchun@xxxxxxxxxxxxx>]

Since we do not change memcg->kmemcg_id before calling
memcg_drain_all_list_lrus(), so we do not need to take kmemcg_id as
parameter. The two parameters of memcg_drain_all_list_lrus() seems
odd, one is kmemcg_id, another is memcg. Now we can change the
kmemcg_id to the memcg. It is more consistent. Since the purpose of
the memcg_drain_all_list_lrus() is list_lru reparenting. So also
rename it to memcg_reparent_list_lrus(). The name is also consistent
with memcg_reparent_objcgs().

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
 include/linux/list_lru.h |  2 +-
 mm/list_lru.c            | 23 ++++++++++++-----------
 mm/memcontrol.c          |  2 +-
 3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index 9dcaa3e582c9..e8a5e3a2c0dd 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -70,7 +70,7 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware,
 	__list_lru_init((lru), true, NULL, shrinker)
 
 int memcg_update_all_list_lrus(int num_memcgs);
-void memcg_drain_all_list_lrus(int src_idx, struct mem_cgroup *dst_memcg);
+void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent);
 
 /**
  * list_lru_add: add an element to the lru list's tail
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 4962d48d4410..d78dba5a6dab 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -523,11 +523,11 @@ int memcg_update_all_list_lrus(int new_size)
 	goto out;
 }
 
-static void memcg_drain_list_lru_node(struct list_lru *lru, int nid,
-				      int src_idx, struct mem_cgroup *dst_memcg)
+static void memcg_reparent_list_lru_node(struct list_lru *lru, int nid,
+					 struct mem_cgroup *memcg,
+					 struct mem_cgroup *parent)
 {
 	struct list_lru_node *nlru = &lru->node[nid];
-	int dst_idx = dst_memcg->kmemcg_id;
 	struct list_lru_one *src, *dst;
 
 	/*
@@ -536,22 +536,23 @@ static void memcg_drain_list_lru_node(struct list_lru *lru, int nid,
 	 */
 	spin_lock_irq(&nlru->lock);
 
-	src = list_lru_from_memcg_idx(nlru, src_idx);
-	dst = list_lru_from_memcg_idx(nlru, dst_idx);
+	src = list_lru_from_memcg_idx(nlru, memcg->kmemcg_id);
+	dst = list_lru_from_memcg_idx(nlru, parent->kmemcg_id);
 
 	list_splice_init(&src->list, &dst->list);
 
 	if (src->nr_items) {
 		dst->nr_items += src->nr_items;
-		set_shrinker_bit(dst_memcg, nid, lru_shrinker_id(lru));
+		set_shrinker_bit(parent, nid, lru_shrinker_id(lru));
 		src->nr_items = 0;
 	}
 
 	spin_unlock_irq(&nlru->lock);
 }
 
-static void memcg_drain_list_lru(struct list_lru *lru,
-				 int src_idx, struct mem_cgroup *dst_memcg)
+static void memcg_reparent_list_lru(struct list_lru *lru,
+				    struct mem_cgroup *memcg,
+				    struct mem_cgroup *parent)
 {
 	int i;
 
@@ -559,16 +560,16 @@ static void memcg_drain_list_lru(struct list_lru *lru,
 		return;
 
 	for_each_node(i)
-		memcg_drain_list_lru_node(lru, i, src_idx, dst_memcg);
+		memcg_reparent_list_lru_node(lru, i, memcg, parent);
 }
 
-void memcg_drain_all_list_lrus(int src_idx, struct mem_cgroup *dst_memcg)
+void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent)
 {
 	struct list_lru *lru;
 
 	mutex_lock(&list_lrus_mutex);
 	list_for_each_entry(lru, &list_lrus, list)
-		memcg_drain_list_lru(lru, src_idx, dst_memcg);
+		memcg_reparent_list_lru(lru, memcg, parent);
 	mutex_unlock(&list_lrus_mutex);
 }
 #else
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 21e12312509c..c1ce4fdba028 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3503,7 +3503,7 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
 	BUG_ON(kmemcg_id < 0);
 
 	/* memcg_reparent_objcgs() must be called before this. */
-	memcg_drain_all_list_lrus(kmemcg_id, parent);
+	memcg_reparent_list_lrus(memcg, parent);
 
 	memcg_free_cache_id(kmemcg_id);
 }
-- 
2.11.0