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From: Wei Yang <richard.weiyang@gmail.com>
To: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
	akpm@linux-foundation.org
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
	Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH 2/3] mm/memcg: set pos to prev unconditionally
Date: Fri, 25 Feb 2022 00:34:36 +0000	[thread overview]
Message-ID: <20220225003437.12620-3-richard.weiyang@gmail.com> (raw)
In-Reply-To: <20220225003437.12620-1-richard.weiyang@gmail.com>

Current code set pos to prev based on condition (prev && !reclaim),
while we can do this unconditionally.

Since:

  * If !reclaim, pos is the same as prev no matter it is NULL or not.
  * If reclaim, pos would be set properly from iter->position.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
 mm/memcontrol.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9464fe2aa329..03399146168f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -980,7 +980,7 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 	struct mem_cgroup_reclaim_iter *iter;
 	struct cgroup_subsys_state *css = NULL;
 	struct mem_cgroup *memcg = NULL;
-	struct mem_cgroup *pos = NULL;
+	struct mem_cgroup *pos = prev;
 
 	if (mem_cgroup_disabled())
 		return NULL;
@@ -988,9 +988,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 	if (!root)
 		root = root_mem_cgroup;
 
-	if (prev && !reclaim)
-		pos = prev;
-
 	rcu_read_lock();
 
 	if (reclaim) {
-- 
2.33.1



  parent reply	other threads:[~2022-02-25  0:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-25  0:34 [PATCH 0/3] mm/memcg: some cleanup for mem_cgroup_iter() Wei Yang
2022-02-25  0:34 ` [PATCH 1/3] mm/memcg: set memcg after css verified and got reference Wei Yang
2022-03-29 18:44   ` Johannes Weiner
2022-02-25  0:34 ` Wei Yang [this message]
2022-03-29 18:48   ` [PATCH 2/3] mm/memcg: set pos to prev unconditionally Johannes Weiner
2022-03-30  0:47     ` Wei Yang
2022-03-30 12:08       ` Johannes Weiner
2022-03-30 14:22         ` Wei Yang
2022-02-25  0:34 ` [PATCH 3/3] mm/memcg: move generation assignment and comparison together Wei Yang
2022-03-30 15:57   ` Johannes Weiner
2022-03-30 23:04     ` Wei Yang
2022-02-25  8:13 ` [PATCH 0/3] mm/memcg: some cleanup for mem_cgroup_iter() Michal Hocko

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