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(and not just inherit it fr= om a >>>> previous allocation that didn't clear it?). >>> >>> We ran into that check in the past, when folio->X overlayed page->priva= te in a tail, and would actually have to be zeroed out. >> >> Currently, _mm_id (_mm_ids) overlaps with page->private. At split time, >> it should be MM_ID_DUMMY (0), so page->private should be 0 all time. > > Yes, it's designed like that; because that check here caught it during de= velopment :) > >> >>> >>> So it should be part of this splitting code I think. >> >> It is still better to have the check and fix in place. Why do we want to >> skip device private folio? > > I don't understand the question, can you elaborate? You said, =E2=80=9CBTW, I wonder whether we should bring that check back for non-devi= ce folios.=E2=80=9D I thought you know why device folio needs to keep ->private not cleared dur= ing split. > I asked Balbir why the check was dropped in the first place. Best Regards, Yan, Zi