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From:   Waiman Long <longman@redhat.com>
To:     Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>
Cc:     linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        linux-mm@kvack.org, Shakeel Butt <shakeelb@google.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Waiman Long <longman@redhat.com>
Subject: [PATCH 2/3] mm, memcg: Remove obsolete memcg_free_kmem()
Date:   Fri,  1 Oct 2021 15:09:37 -0400
Message-Id: <20211001190938.14050-3-longman@redhat.com>
In-Reply-To: <20211001190938.14050-1-longman@redhat.com>
References: <20211001190938.14050-1-longman@redhat.com>
Precedence: bulk

Since commit d648bcc7fe65 ("mm: kmem: make memcg_kmem_enabled()
irreversible"), the only thing memcg_free_kmem() does is to call
memcg_offline_kmem() when the memcg is still online. However,
memcg_offline_kmem() is only called from mem_cgroup_css_free() which
cannot be reached if the memcg hasn't been offlined first. As this
function now serves no purpose, we should just remove it.

Signed-off-by: Waiman Long <longman@redhat.com>
---
 mm/memcontrol.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4568363062c1..8177f253a127 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3673,13 +3673,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg)
 
 	memcg_free_cache_id(kmemcg_id);
 }
-
-static void memcg_free_kmem(struct mem_cgroup *memcg)
-{
-	/* css_alloc() failed, offlining didn't happen */
-	if (unlikely(memcg->kmem_state == KMEM_ONLINE))
-		memcg_offline_kmem(memcg);
-}
 #else
 static int memcg_online_kmem(struct mem_cgroup *memcg)
 {
@@ -3688,9 +3681,6 @@ static int memcg_online_kmem(struct mem_cgroup *memcg)
 static void memcg_offline_kmem(struct mem_cgroup *memcg)
 {
 }
-static void memcg_free_kmem(struct mem_cgroup *memcg)
-{
-}
 #endif /* CONFIG_MEMCG_KMEM */
 
 static int memcg_update_kmem_max(struct mem_cgroup *memcg,
@@ -5325,7 +5315,6 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
 	cancel_work_sync(&memcg->high_work);
 	mem_cgroup_remove_from_trees(memcg);
 	free_shrinker_info(memcg);
-	memcg_free_kmem(memcg);
 	mem_cgroup_free(memcg);
 }
 
-- 
2.18.1