MEMCG_DATA_KMEM
return folio->memcg_data & MEMCG_DATA_KMEM;
VM_BUG_ON_PAGE((memcg_data & OBJEXTS_FLAGS_MASK) != MEMCG_DATA_KMEM,
return (struct obj_cgroup *)(memcg_data - MEMCG_DATA_KMEM);
page->memcg_data = (unsigned long)objcg | MEMCG_DATA_KMEM;
VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab));