diff options
| author | Muchun Song <songmuchun@bytedance.com> | 2021-11-05 23:37:53 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-06 23:30:35 +0300 |
| commit | 642688681133a501d149349ba1a824204f3540e1 (patch) | |
| tree | 76e6ddbc4d7bc20f84c0c26679208694963ed858 /mm/memcontrol.c | |
| parent | 41d17431df4aa7c57761e04f81c94fb3c3beedf4 (diff) | |
| download | linux-642688681133a501d149349ba1a824204f3540e1.tar.xz | |
mm: memcontrol: remove kmemcg_id reparenting
Since slab objects and kmem pages are charged to object cgroup instead
of memory cgroup, memcg_reparent_objcgs() will reparent this cgroup and
all its descendants to its parent cgroup. This already makes further
list_lru_add()'s add elements to the parent's list. So it is
unnecessary to change kmemcg_id of an offline cgroup to its parent's id.
It just wastes CPU cycles. Just remove the redundant code.
Link: https://lkml.kernel.org/r/20211025125102.56533-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 19 |
1 files changed, 4 insertions, 15 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e4fcb6e55f75..1e2d3f378edd 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3650,8 +3650,7 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) static void memcg_offline_kmem(struct mem_cgroup *memcg) { - struct cgroup_subsys_state *css; - struct mem_cgroup *parent, *child; + struct mem_cgroup *parent; int kmemcg_id; if (memcg->kmem_state != KMEM_ONLINE) @@ -3669,21 +3668,11 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) BUG_ON(kmemcg_id < 0); /* - * Change kmemcg_id of this cgroup and all its descendants to the - * parent's id, and then move all entries from this cgroup's list_lrus - * to ones of the parent. After we have finished, all list_lrus - * corresponding to this cgroup are guaranteed to remain empty. The - * ordering is imposed by list_lru_node->lock taken by + * After we have finished memcg_reparent_objcgs(), all list_lrus + * corresponding to this cgroup are guaranteed to remain empty. + * The ordering is imposed by list_lru_node->lock taken by * memcg_drain_all_list_lrus(). */ - rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */ - css_for_each_descendant_pre(css, &memcg->css) { - child = mem_cgroup_from_css(css); - BUG_ON(child->kmemcg_id != kmemcg_id); - child->kmemcg_id = parent->kmemcg_id; - } - rcu_read_unlock(); - memcg_drain_all_list_lrus(kmemcg_id, parent); memcg_free_cache_id(kmemcg_id); |