[patch 057/262] mm/memcg: remove obsolete memcg_free_kmem()

Andrew Morton
2021-11-05T20:37:40Z

From: Waiman Long <longman@redhat.com>
Subject: mm/memcg: remove obsolete memcg_free_kmem()

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 which can happen when
online_css() fails due to -ENOMEM. However, the name memcg_free_kmem() is
confusing and it is more clear and straight forward to call
memcg_offline_kmem() directly from mem_cgroup_css_free().

Link: https://lkml.kernel.org/r/20211005202450.11775-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Suggested-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

mm/memcontrol.c | 14 +++-----------
1 file changed, 3 insertions(+), 11 deletions(-)

--- a/mm/memcontrol.c~mm-memcg-remove-obsolete-memcg_free_kmem
+++ a/mm/memcontrol.c
@@ -3704,13 +3704,6 @@ static void memcg_offline_kmem(struct me

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)
{
@@ -3719,9 +3712,6 @@ static int memcg_online_kmem(struct mem_
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,
@@ -5356,7 +5346,9 @@ static void mem_cgroup_css_free(struct c
cancel_work_sync(&memcg->high_work);
mem_cgroup_remove_from_trees(memcg);
free_shrinker_info(memcg);
- memcg_free_kmem(memcg);
+
+ /* Need to offline kmem if online_css() fails */
+ memcg_offline_kmem(memcg);
mem_cgroup_free(memcg);
}

_