Messages in this thread | | | Date | Tue, 3 Oct 2023 09:42:00 +0200 | From | Andrew Jones <> | Subject | Re: [PATCH -fixes 2/2] riscv: Fix set_huge_pte_at() for NAPOT mappings when a swap entry is set |
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On Thu, Sep 28, 2023 at 05:18:46PM +0200, Alexandre Ghiti wrote: > We used to determine the number of page table entries to set for a NAPOT > hugepage by using the pte value which actually fails when the pte to set is > a swap entry. > > So take advantage of a recent fix for arm64 reported in [1] which > introduces the size of the mapping as an argument of set_huge_pte_at(): we > can then use this size to compute the number of page table entries to set > for a NAPOT region. > > Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page") > Reported-by: Ryan Roberts <ryan.roberts@arm.com> > Closes: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@arm.com/ [1] > Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> > --- > arch/riscv/mm/hugetlbpage.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c > index e4a2ace92dbe..b52f0210481f 100644 > --- a/arch/riscv/mm/hugetlbpage.c > +++ b/arch/riscv/mm/hugetlbpage.c > @@ -183,15 +183,22 @@ void set_huge_pte_at(struct mm_struct *mm, > pte_t pte, > unsigned long sz) > { > + unsigned long hugepage_shift; > int i, pte_num; > > - if (!pte_napot(pte)) { > - set_pte_at(mm, addr, ptep, pte); > - return; > - } > + if (sz >= PGDIR_SIZE) > + hugepage_shift = PGDIR_SHIFT; > + else if (sz >= P4D_SIZE) > + hugepage_shift = P4D_SHIFT; > + else if (sz >= PUD_SIZE) > + hugepage_shift = PUD_SHIFT; > + else if (sz >= PMD_SIZE) > + hugepage_shift = PMD_SHIFT; > + else > + hugepage_shift = PAGE_SHIFT; > > - pte_num = napot_pte_num(napot_cont_order(pte)); > - for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE) > + pte_num = sz >> hugepage_shift; > + for (i = 0; i < pte_num; i++, ptep++, addr += (1 << hugepage_shift)) > set_pte_at(mm, addr, ptep, pte); > } >
So a 64k napot, for example, will fall into the PAGE_SHIFT arm, but then we'll calculate 16 for pte_num. Looks good to me.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Thanks, drew
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