On Sat, May 09, 2020 at 06:11:57PM -0700, Matthew Wilcox wrote: > Iterating an XArray (whether the entire thing > or with marks) is RCU-safe and faster than iterating a linked list, > so this should solve the problem? It can hardly be faster if you want all elements -- which is I think the case here. We only call into this if we change an entry, and then we need to propagate that change to all.