From 675d6c9b59e313ca2573c93e8fd87011a99bb8ce Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 19 Oct 2023 15:53:43 -0700 Subject: mm: kmem: make memcg keep a reference to the original objcg Keep a reference to the original objcg object for the entire life of a memcg structure. This allows to simplify the synchronization on the kernel memory allocation paths: pinning a (live) memcg will also pin the corresponding objcg. The memory overhead of this change is minimal because object cgroups usually outlive their corresponding memory cgroups even without this change, so it's only an additional pointer per memcg. Link: https://lkml.kernel.org/r/20231019225346.1822282-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) Tested-by: Naresh Kamboju Acked-by: Shakeel Butt Reviewed-by: Vlastimil Babka Cc: David Rientjes Cc: Dennis Zhou Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/memcontrol.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 96f4c319f025..ff036d5d339d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3899,6 +3899,8 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) objcg->memcg = memcg; rcu_assign_pointer(memcg->objcg, objcg); + obj_cgroup_get(objcg); + memcg->orig_objcg = objcg; static_branch_enable(&memcg_kmem_online_key); @@ -5406,6 +5408,9 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; + if (memcg->orig_objcg) + obj_cgroup_put(memcg->orig_objcg); + for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); kfree(memcg->vmstats); -- cgit