mm: list_lru: rename memcg_drain_all_list_lrus to memcg_reparent_list_lrus

The purpose of the memcg_drain_all_list_lrus() is list_lrus reparenting.
It is very similar to memcg_reparent_objcgs(). Rename it to
memcg_reparent_list_lrus() so that the name can more consistent with
memcg_reparent_objcgs().

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Muchun Song <[e-mail]>
Cc: Alex Shi <[e-mail]>
Cc: Anna Schumaker <[e-mail]>
Cc: Chao Yu <[e-mail]>
Cc: Dave Chinner <[e-mail]>
Cc: Fam Zheng <[e-mail]>
Cc: Jaegeuk Kim <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Kari Argillander <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Qi Zheng <[e-mail]>
Cc: Roman Gushchin <[e-mail]>
Cc: Shakeel Butt <[e-mail]>
Cc: Theodore Ts'o <[e-mail]>
Cc: Trond Myklebust <[e-mail]>
Cc: Vladimir Davydov <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Wei Yang <[e-mail]>
Cc: Xiongchun Duan <[e-mail]>
Cc: Yang Shi <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/list_lru.h

···
 int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru,
 			 gfp_t gfp);
 int memcg_update_all_list_lrus(int num_memcgs);
-void memcg_drain_all_list_lrus(struct mem_cgroup *src, struct mem_cgroup *dst);
+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

mm/list_lru.c

···
 	return ret;
 }
 
-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,
+					 int src_idx, struct mem_cgroup *dst_memcg)
 {
 	struct list_lru_node *nlru = &lru->node[nid];
 	int dst_idx = dst_memcg->kmemcg_id;
···
 	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,
+				    int src_idx, struct mem_cgroup *dst_memcg)
 {
 	int i;
 
 	for_each_node(i)
-		memcg_drain_list_lru_node(lru, i, src_idx, dst_memcg);
+		memcg_reparent_list_lru_node(lru, i, src_idx, dst_memcg);
 
 	memcg_list_lru_free(lru, src_idx);
 }
 
-void memcg_drain_all_list_lrus(struct mem_cgroup *src, struct mem_cgroup *dst)
+void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent)
 {
 	struct cgroup_subsys_state *css;
 	struct list_lru *lru;
-	int src_idx = src->kmemcg_id;
+	int src_idx = memcg->kmemcg_id;
 
 	/*
 	 * Change kmemcg_id of this cgroup and all its descendants to the
···
 	 * call.
 	 */
 	rcu_read_lock();
-	css_for_each_descendant_pre(css, &src->css) {
-		struct mem_cgroup *memcg;
+	css_for_each_descendant_pre(css, &memcg->css) {
+		struct mem_cgroup *child;
 
-		memcg = mem_cgroup_from_css(css);
-		memcg->kmemcg_id = dst->kmemcg_id;
+		child = mem_cgroup_from_css(css);
+		child->kmemcg_id = parent->kmemcg_id;
 	}
 	rcu_read_unlock();
 
 	mutex_lock(&list_lrus_mutex);
 	list_for_each_entry(lru, &memcg_list_lrus, list)
-		memcg_drain_list_lru(lru, src_idx, dst);
+		memcg_reparent_list_lru(lru, src_idx, parent);
 	mutex_unlock(&list_lrus_mutex);
 }
 

mm/memcontrol.c

···
 	memcg_reparent_objcgs(memcg, parent);
 
 	/*
-	 * memcg_drain_all_list_lrus() can change memcg->kmemcg_id.
+	 * memcg_reparent_list_lrus() can change memcg->kmemcg_id.
 	 * Cache it to local @kmemcg_id.
 	 */
 	kmemcg_id = memcg->kmemcg_id;
···
 	 * After we have finished memcg_reparent_objcgs(), all list_lrus
 	 * corresponding to this cgroup are guaranteed to remain empty.
 	 * The ordering is imposed by list_lru_node->lock taken by
-	 * memcg_drain_all_list_lrus().
+	 * memcg_reparent_list_lrus().
 	 */
-	memcg_drain_all_list_lrus(memcg, parent);
+	memcg_reparent_list_lrus(memcg, parent);
 
 	memcg_free_cache_id(kmemcg_id);
 }