| Message ID | 20250415024532.26632-2-songmuchun@bytedance.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Eliminate Dying Memory Cgroup | expand |
On Tue, Apr 15, 2025 at 10:45:05AM +0800, Muchun Song wrote: > Since the no-hierarchy mode has been deprecated after the commit: > > commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical mode"). > > As a result, parent_mem_cgroup() will not return NULL except when passing > the root memcg, and the root memcg cannot be offline. Hence, it's safe to > remove the check on the returned value of parent_mem_cgroup(). Remove the > corresponding dead code. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 421740f1bcdc..61488e45cab2 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3196,9 +3196,6 @@ static void memcg_offline_kmem(struct mem_cgroup *memcg) return; parent = parent_mem_cgroup(memcg); - if (!parent) - parent = root_mem_cgroup; - memcg_reparent_list_lrus(memcg, parent); /* @@ -3489,8 +3486,6 @@ struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) break; } memcg = parent_mem_cgroup(memcg); - if (!memcg) - memcg = root_mem_cgroup; } return memcg; } diff --git a/mm/shrinker.c b/mm/shrinker.c index 4a93fd433689..e8e092a2f7f4 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -286,14 +286,10 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) { int nid, index, offset; long nr; - struct mem_cgroup *parent; + struct mem_cgroup *parent = parent_mem_cgroup(memcg); struct shrinker_info *child_info, *parent_info; struct shrinker_info_unit *child_unit, *parent_unit; - parent = parent_mem_cgroup(memcg); - if (!parent) - parent = root_mem_cgroup; - /* Prevent from concurrent shrinker_info expand */ mutex_lock(&shrinker_mutex); for_each_node(nid) {
Since the no-hierarchy mode has been deprecated after the commit: commit bef8620cd8e0 ("mm: memcg: deprecate the non-hierarchical mode"). As a result, parent_mem_cgroup() will not return NULL except when passing the root memcg, and the root memcg cannot be offline. Hence, it's safe to remove the check on the returned value of parent_mem_cgroup(). Remove the corresponding dead code. Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> --- mm/memcontrol.c | 5 ----- mm/shrinker.c | 6 +----- 2 files changed, 1 insertion(+), 10 deletions(-)