linux-kernel - [PATCH v2 08/21] mm: list_lru: remove memcg_aware field from struct list

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Message-Id: <20210527062148.9361-9-songmuchun@bytedance.com>
Date:   Thu, 27 May 2021 14:21:35 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     willy@...radead.org, akpm@...ux-foundation.org, hannes@...xchg.org,
        mhocko@...nel.org, vdavydov.dev@...il.com, shakeelb@...gle.com,
        guro@...com, shy828301@...il.com, alexs@...nel.org,
        richard.weiyang@...il.com, david@...morbit.com,
        trond.myklebust@...merspace.com, anna.schumaker@...app.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-nfs@...r.kernel.org,
        zhengqi.arch@...edance.com, duanxiongchun@...edance.com,
        fam.zheng@...edance.com, Muchun Song <songmuchun@...edance.com>
Subject: [PATCH v2 08/21] mm: list_lru: remove memcg_aware field from struct list_lru

We can use ->memcg_lrus to indicate if the list_lru is memcg aware.
So ->memcg_aware is redundant and just remove it.

Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 include/linux/list_lru.h | 1 -
 mm/list_lru.c            | 9 +++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index 20a43904001d..4a9e4aaecc69 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -55,7 +55,6 @@ struct list_lru {
 #ifdef CONFIG_MEMCG_KMEM
 	struct list_head	list;
 	int			shrinker_id;
-	bool			memcg_aware;
 	/* for cgroup aware lrus points to per cgroup lists, otherwise NULL */
 	struct list_lru_memcg	__rcu *memcg_lrus;
 #endif
diff --git a/mm/list_lru.c b/mm/list_lru.c
index e52f5a91fa0f..8006c0fcc506 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -20,7 +20,7 @@ static DEFINE_MUTEX(list_lrus_mutex);
 
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
 {
-	return lru->memcg_aware;
+	return !!rcu_access_pointer(lru->memcg_lrus);
 }
 
 static void list_lru_register(struct list_lru *lru)
@@ -73,7 +73,7 @@ list_lru_from_kmem(struct list_lru *lru, int nid, void *ptr,
 	struct list_lru_one *l = &nlru->lru;
 	struct mem_cgroup *memcg = NULL;
 
-	if (!lru->memcg_lrus)
+	if (!list_lru_memcg_aware(lru))
 		goto out;
 
 	memcg = mem_cgroup_from_obj(ptr);
@@ -367,9 +367,10 @@ static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 	struct list_lru_memcg *memcg_lrus;
 	int size = memcg_nr_cache_ids;
 
-	lru->memcg_aware = memcg_aware;
-	if (!memcg_aware)
+	if (!memcg_aware) {
+		lru->memcg_lrus = NULL;
 		return 0;
+	}
 
 	memcg_lrus = kvmalloc(sizeof(*memcg_lrus) +
 			      size * sizeof(memcg_lrus->lrus[0]), GFP_KERNEL);
-- 
2.11.0