On Fri, Aug 30, 2019 at 05:40:23PM +0200, Jan Kara wrote: > Are the page dereferences above safe? I suppose lock_page_memcg() protects > the page->mem_cgroup->css.cgroup->kn->id dereference? But page->mapping > does not seem to be protected by page lock? Forgot to respond to the mem_cgroup part. The page to memcg association never changes on cgroup2 as long as the page has ref, so I think that one should be safe. Thanks. -- tejun
