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From:   Muchun Song <songmuchun@bytedance.com>
To:     willy@infradead.org, akpm@linux-foundation.org, hannes@cmpxchg.org,
        mhocko@kernel.org, vdavydov.dev@gmail.com, shakeelb@google.com,
        guro@fb.com, shy828301@gmail.com, alexs@kernel.org,
        richard.weiyang@gmail.com, david@fromorbit.com,
        trond.myklebust@hammerspace.com, anna.schumaker@netapp.com
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-nfs@vger.kernel.org,
        zhengqi.arch@bytedance.com, duanxiongchun@bytedance.com,
        fam.zheng@bytedance.com, Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH 06/17] mm: list_lru: only add the memcg aware lrus to the list
Date:   Tue, 11 May 2021 18:46:36 +0800
Message-Id: <20210511104647.604-7-songmuchun@bytedance.com>
In-Reply-To: <20210511104647.604-1-songmuchun@bytedance.com>
References: <20210511104647.604-1-songmuchun@bytedance.com>
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Precedence: bulk

We need to traverse every lru in the list_lrus in some routines, but skip
the non memcg aware lru. Actually, we can only add the memcg aware lrus to
the list. This can be efficient.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/list_lru.c | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/mm/list_lru.c b/mm/list_lru.c
index e86d4d055d3c..bed699edabe5 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -18,8 +18,16 @@
 static LIST_HEAD(list_lrus);
 static DEFINE_MUTEX(list_lrus_mutex);
 
+static inline bool list_lru_memcg_aware(struct list_lru *lru)
+{
+	return lru->memcg_aware;
+}
+
 static void list_lru_register(struct list_lru *lru)
 {
+	if (!list_lru_memcg_aware(lru))
+		return;
+
 	mutex_lock(&list_lrus_mutex);
 	list_add(&lru->list, &list_lrus);
 	mutex_unlock(&list_lrus_mutex);
@@ -27,6 +35,9 @@ static void list_lru_register(struct list_lru *lru)
 
 static void list_lru_unregister(struct list_lru *lru)
 {
+	if (!list_lru_memcg_aware(lru))
+		return;
+
 	mutex_lock(&list_lrus_mutex);
 	list_del(&lru->list);
 	mutex_unlock(&list_lrus_mutex);
@@ -37,11 +48,6 @@ static int lru_shrinker_id(struct list_lru *lru)
 	return lru->shrinker_id;
 }
 
-static inline bool list_lru_memcg_aware(struct list_lru *lru)
-{
-	return lru->memcg_aware;
-}
-
 static inline struct list_lru_one *
 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
 {
@@ -460,9 +466,6 @@ static int memcg_update_list_lru(struct list_lru *lru,
 {
 	int i;
 
-	if (!list_lru_memcg_aware(lru))
-		return 0;
-
 	for_each_node(i) {
 		if (memcg_update_list_lru_node(&lru->node[i],
 					       old_size, new_size))
@@ -485,9 +488,6 @@ static void memcg_cancel_update_list_lru(struct list_lru *lru,
 {
 	int i;
 
-	if (!list_lru_memcg_aware(lru))
-		return;
-
 	for_each_node(i)
 		memcg_cancel_update_list_lru_node(&lru->node[i],
 						  old_size, new_size);
@@ -546,9 +546,6 @@ static void memcg_drain_list_lru(struct list_lru *lru,
 {
 	int i;
 
-	if (!list_lru_memcg_aware(lru))
-		return;
-
 	for_each_node(i)
 		memcg_drain_list_lru_node(lru, i, src_idx, dst_memcg);
 }
-- 
2.11.0