On Tue, Mar 28, 2023 at 08:18:11AM -0700, Shakeel Butt wrote: > > @@ -406,6 +406,8 @@ void workingset_refault(struct folio *folio, void *shadow) > > unpack_shadow(shadow, &memcgid, &pgdat, &eviction, &workingset); > > eviction <<= bucket_order; > > > > + /* Flush stats (and potentially sleep) before holding RCU read lock */ > > I think the only reason we use rcu lock is due to > mem_cgroup_from_id(). Maybe we should add mem_cgroup_tryget_from_id(). > The other caller of mem_cgroup_from_id() in vmscan is already doing > the same and could use mem_cgroup_tryget_from_id(). Good catch. Nothing else in there is protected by RCU. We can just hold the ref instead. > Though this can be done separately to this series (if we decide to do > it at all). Agreed
