On Mon, Dec 20, 2021 at 04:56:46PM +0800, Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote: > There are two idrs being used by memory cgroup, one is for kmem ID, > another is for memory cgroup ID. The maximum ID of both is 64Ki. > Both of them can limit the total number of memory cgroups. > Actually, we can reuse memory cgroup ID for kmem ID to simplify the > code. An interesting improvement. I'm a bit dense -- what's the purpose the MEM_CGROUP_ID_DIFF offset? Couldn't this deduplication be extended to only use mem_cgroup.id.id instead of mem_cgroup.kmemcg_id? (With a boolean telling whether kmem accounting is active.) Thanks, Michal