On Wed, Sep 27, 2023 at 03:29:35PM +0200, David Hildenbrand wrote:
+ if (!pte_same(*src_pte, orig_src_pte) ||
+ !pte_same(*dst_pte, orig_dst_pte) ||
+ folio_test_large(src_folio) ||
+ folio_estimated_sharers(src_folio) != 1) {
^ here you should check PageAnonExclusive. Please get rid of any implicit
explicit/implcit mapcount checks.
David, is PageAnon 100% accurate now in the current tree?
IOW, can it be possible that the page has total_mapcount==1 but missing
AnonExclusive bit in any possible way?