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> On Tue, Oct 15, 2024 at 4:40=E2=80=AFPM David Hildenbrand wrote: >> On 15.10.24 16:32, Kirill A. Shutemov wrote: >>> On Tue, Oct 15, 2024 at 01:12:36PM +0200, David Hildenbrand wrote: >>>> pmd_leaf()/pud_leaf() only implies a pmd_present()/pud_present() che= ck on >>>> some architectures. >>> >>> Should we clarify what behaviour we actually want from arch code? >> >> We probably should document somewhere that things like pmd_special(), >> pmd_leaf() ... should only be used when we know that the PMD is presen= t. >> >> I wonder if we should even add ways to detect mis-use >> >> Jann also raised that recently in a private message, that it is rather= >> unclear (well, and repeatedly leads to issues) when pmd_leaf() is vali= d >> to be called. > > I think one place where that should probably be addressed is in > Documentation/mm/arch_pgtable_helpers.rst - that is supposed to be an > overview of these helper functions and what they mean, but the only > thing it currently says about pmd_leaf() is "Tests a leaf mapped PMD", > which doesn't really tell you much more than the function name. It > would be nice if that table contained information about the conditions > under which these helpers may be used. I find the related documentation in include/linux/pgtable.h [1], but it i= s not an easy find. [1] https://elixir.bootlin.com/linux/v6.11.3/source/include/linux/pgtable= =2Eh#L1865 Best Regards, Yan, Zi --=_MailMate_6684DAA8-7A91-48F9-B0DF-B037AC4119CF_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAmcOjgoPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqKv7gP/RADZ2mzmdP5fOtk/n0lzNkG8fixRcKH4TKI dxJGrI+V+tR0SYSxVQwHk3uGPdoRiFzWfFyDtmsAP3O3s0mqAfFgz6EHh8uGBrEV wQNs3tUc3dHcXz9XbuO4CmsQZjeOzxM4uoekR1wFNnxiGaNYCwzYDnPGi2LXH/Dw co+Zy5T10WEKUaXnUxzJki6fTaL5467eEz3fU4YAHFAaV1WcrpF8JkfaHVSH3wIg N/Lm5SSTTNZENzYwALZCyF2E3F3nDpIFo1YNOXdeZuli0uLwIRyFWoywsBl9D4lX eE99AGqeSUVhsdPJ+wCCbHycutQekrtcg4bddu66szWY0N2gUyVa/ErqGgdLEnbu MRFXLS9HFEHY9jlBwuFs1j2k4LKRM8TTTvt17S3Iyl0ukPqyD9yG06VK78uclaLW 2qPyDOCrekk97y30Op1VM6lvL4cTHS9nxYcHpgUkKTrCGIZPfvsCAQiJTHkjwqFs m9WSRQkReRgZz6gDDxKm8BFqMIFEvMJCCoXew08BqaYLKiRQNfPP1YHo2MqyQMBU Ll6HX8X+RsSuB5+rEnAlMRssHPFVPDHwSlf8MIQfsVFK2EKN1C1MhnJsAs1Cgsgb y4p69Y3bDx+xFaB4w4ndroPCXKSFDhP2JOuedVk+i7XLIuFpg+rsQQXII7HEnPXA SjE9xKjK =jRAB -----END PGP SIGNATURE----- --=_MailMate_6684DAA8-7A91-48F9-B0DF-B037AC4119CF_=--