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U2FsdGVkX1/+8qJnBbTxtQHOjnkYdqAHVgi1Dl/nyljNuqrhz/dy3WhOjp2wGdz4qmceJ/uFedbAR4GZF6VmTQpeaYo5lPAnmnbNeJf+8WaWpat/pwodc0UBdX3RQfdzBn3tAm920Q9bIMpc+g+kpafov1qBqYx5xN9drTylKd66UxLjAMQtNlS2j+XKLTsIMqgosusSal4huMQPUUu4iiEYzRrhHGdNRRS6lOhFhAn1gTG9aVQlmLdcvEPbmUuWCc1KiPtGgJUKlQ8kOTMP0agFgyu7kjqtss1o13y84OscKt57NOkR066Bf6LKTRWjTHav+4Af+3b4O5B9UJ8z8c7wFU/eNejQEKOlF0poN29ONN/Kym28YsHNASJcE703O4BMJ+/sZBSHMQX4hsa20Vgc0tR6E20g0asVzhkonHOr1NFsWTVLr7FtU3wGDtKnsGKi3Dimu1LsnKxQBSN+wxQJogQz0eaJncRVTMQklNjYySU/6fjGvaqpTB/Gv83eUn4tE8m8z1ulq3lGmMKtEqbKKaJxmYk6J9D+oKyor+PjnsTdtPqN2BPF06QiHqCy7E215OI92ODT52TFcFu2Wac212/0+OpnVAKQEqrdXuDiIrdCN3QN1Lei98Kfr3peGqG/7vSHvPb99MOINvfYGbS8OiRMpbPwhgHdhayBdDYhSoveK4QQ4zVUXGptZy00QGce5+Z0oij6RZ7WRs7r5HXGHVjUT7YRRsLDy5nffaRL/fhTSyNZaKv6GUMcBqQVwO4im2UsycrSXNimJJEIdw0F+1+WrW+rtkNrVJXsTJhLGryC6gCqXc3H189aXHcQB7dkKvmL2EW6h+sou030ByNx6VUHODisr2h8nSAzzERHNtgADu06dDJS4Smt2y4s8zCFwy0p0qUa+9JY5p37rVLZYomb9lIM3Wrzs5t0im2HsoiurFmwfTjfsl1vvTBudw6j1tednvtfYOVg0p1 UmJ63vlP 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kernel is unclear. We have two > groups that think differently on swap entries: > > - x86/sparc: Allow pXd_huge() to accept swap entries > - all the rest: Doesn't allow pXd_huge() to accept swap entries > > This is so confusing. Since the sparc helpers seem to be added in 2016, > which is after x86's (2015), so sparc could have followed a trend. x86 > proposed such swap handling in 2015 to resolve hugetlb swap entries hit in > GUP, but now GUP guards swap entries with !pXd_present() in all layers so > we should be safe. > > We should define this API properly, one way or another, rather than keep > them defined differently across archs. > > Gut feeling tells me that pXd_huge() shouldn't include swap entries, and it > turns out that I am not the only one thinking so, the question was raised > when the current pmd_huge() for x86 was proposed by Ville Syrjälä: > > https://lore.kernel.org/all/Y2WQ7I4LXh8iUIRd@intel.com/ > > I might also be missing something obvious, but why is it even necessary > to treat PRESENT==0+PSE==0 as a huge entry? > > It is also questioned when Jason Gunthorpe reviewed the other patchset on > swap entry handlings: > > https://lore.kernel.org/all/20240221125753.GQ13330@nvidia.com/ > > Revert its meaning back to original. It shouldn't have any functional > change as we should be ready with guards on !pXd_present() explicitly > everywhere. > > Note that I also dropped the "#if CONFIG_PGTABLE_LEVELS > 2", it was there > probably because it was breaking things when 3a194f3f8ad0 was proposed, > according to the report here: > > https://lore.kernel.org/all/Y2LYXItKQyaJTv8j@intel.com/ > > Now we shouldn't need that. > > Instead of reverting to _PAGE_PSE raw check, leverage pXd_leaf(). > > Cc: Naoya Horiguchi > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: Dave Hansen > Cc: x86@kernel.org > Signed-off-by: Peter Xu > --- > arch/x86/mm/hugetlbpage.c | 18 ++++-------------- > 1 file changed, 4 insertions(+), 14 deletions(-) I think this is the right thing to do, callers should be more directly sensitive to swap entries not back into it indirectly from a helper like this. Jason