On Wed, Nov 29, 2023 at 10:04:05AM -0500, Johannes Weiner wrote: > On Mon, Nov 27, 2023 at 03:45:56PM -0800, Nhat Pham wrote: > > The new zswap writeback scheme requires an online-only memcg hierarchy > > traversal. Add this functionality via the new mem_cgroup_iter_online() > > function - the old mem_cgroup_iter() is a special case of this new > > function. > > > > Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx> > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> I saw Michal's reply on the other thread only after I sent this. I agree with him it would be better to just check mem_cgroup_online() in the shinker callsite and leave mem_cgroup_iter() as-is. If it's offline, just continue to the next mem_cgroup_iter() invocation.