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The first time around the loop, we haven't walked the > tree, so we start from the top as you'd expect. The only other reason to > go around the loop again is that memory allocation failed for a node, and > in that case we call xas_nomem() and that (effectively) calls xas_reset(). > > So in terms of the expected API for xa_state users, it would be consistent > for xas_split_alloc() to call xas_reset(). > > You might argue that this API is too subtle, but it was intended to > be easy to use. The problem was that xas_split_alloc() got added much > later and I forgot to maintain the invariant that makes it work as well > as be easy to use. > Ok, missing xas_reset() makes a ton of sense as the root cause, and it also explains why tmpfs hasn't seen the problem. We'll start validating 6.11 and make noise if the large folios cause problems again. Thanks everyone! -chris