| Message ID | 20241029044529.2624785-1-anshuman.khandual@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64/mm: Re-organize arch_make_huge_pte() | expand |
On Tue, 29 Oct 2024 10:15:29 +0530, Anshuman Khandual wrote: > Core HugeTLB defines a fallback definition for arch_make_huge_pte(), which > calls platform provided pte_mkhuge(). But if any platform already provides > an override for arch_make_huge_pte(), then it does not need to provide the > helper pte_mkhuge(). > > arm64 override for arch_make_huge_pte() calls pte_mkhuge() internally, thus > creating an impression, that both of these callbacks are being used in core > HugeTLB and hence required to be defined. This drops off pte_mkhuge() which > was never required to begin with as there could not be any section mappings > at the PTE level. Re-organize arch_make_huge_pte() based on requested page > size and create the entry for the applicable page table level as needed. It > also removes a redundancy of clearing PTE_TABLE_BIT bit followed by setting > both PTE_TABLE_BIT and PTE_VALID bits (via PTE_TYPE_MASK) in the pte, while > creating CONT_PTE_SIZE size entries. > > [...] Applied to arm64 (for-next/misc), thanks! [1/1] arm64/mm: Re-organize arch_make_huge_pte() https://git.kernel.org/arm64/c/f8192813dcbe I think we can now get pte_mkcont() to only set PTE_CONT without touching PTE_TYPE_PAGE. Previously it wasn't possible because pte_mkhuge() was clearing the PTE_TABLE_BIT and we added it back via pte_mkcont(). Give it a try and send an additional patch cleaning up pte_mkcont() if this works. Thanks.
On 11/1/24 23:05, Catalin Marinas wrote: > On Tue, 29 Oct 2024 10:15:29 +0530, Anshuman Khandual wrote: >> Core HugeTLB defines a fallback definition for arch_make_huge_pte(), which >> calls platform provided pte_mkhuge(). But if any platform already provides >> an override for arch_make_huge_pte(), then it does not need to provide the >> helper pte_mkhuge(). >> >> arm64 override for arch_make_huge_pte() calls pte_mkhuge() internally, thus >> creating an impression, that both of these callbacks are being used in core >> HugeTLB and hence required to be defined. This drops off pte_mkhuge() which >> was never required to begin with as there could not be any section mappings >> at the PTE level. Re-organize arch_make_huge_pte() based on requested page >> size and create the entry for the applicable page table level as needed. It >> also removes a redundancy of clearing PTE_TABLE_BIT bit followed by setting >> both PTE_TABLE_BIT and PTE_VALID bits (via PTE_TYPE_MASK) in the pte, while >> creating CONT_PTE_SIZE size entries. >> >> [...] > > Applied to arm64 (for-next/misc), thanks! > > [1/1] arm64/mm: Re-organize arch_make_huge_pte() > https://git.kernel.org/arm64/c/f8192813dcbe > > I think we can now get pte_mkcont() to only set PTE_CONT without > touching PTE_TYPE_PAGE. Previously it wasn't possible because > pte_mkhuge() was clearing the PTE_TABLE_BIT and we added it back via > pte_mkcont(). Give it a try and send an additional patch cleaning up > pte_mkcont() if this works. Thanks. Yes, it does indeed work. Sent the following patch for the same. https://lore.kernel.org/all/20241104041617.3804617-1-anshuman.khandual@arm.com/
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index c329ea061dc9..fa4c32a9f572 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -438,11 +438,6 @@ static inline void __set_ptes(struct mm_struct *mm, } } -/* - * Huge pte definitions. - */ -#define pte_mkhuge(pte) (__pte(pte_val(pte) & ~PTE_TABLE_BIT)) - /* * Hugetlb definitions. */ diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 5f1e2103888b..3215adf48a1b 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -361,14 +361,25 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags) { size_t pagesize = 1UL << shift; - entry = pte_mkhuge(entry); - if (pagesize == CONT_PTE_SIZE) { - entry = pte_mkcont(entry); - } else if (pagesize == CONT_PMD_SIZE) { + switch (pagesize) { +#ifndef __PAGETABLE_PMD_FOLDED + case PUD_SIZE: + entry = pud_pte(pud_mkhuge(pte_pud(entry))); + break; +#endif + case CONT_PMD_SIZE: entry = pmd_pte(pmd_mkcont(pte_pmd(entry))); - } else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) { + fallthrough; + case PMD_SIZE: + entry = pmd_pte(pmd_mkhuge(pte_pmd(entry))); + break; + case CONT_PTE_SIZE: + entry = pte_mkcont(entry); + break; + default: pr_warn("%s: unrecognized huge page size 0x%lx\n", __func__, pagesize); + break; } return entry; }
Core HugeTLB defines a fallback definition for arch_make_huge_pte(), which calls platform provided pte_mkhuge(). But if any platform already provides an override for arch_make_huge_pte(), then it does not need to provide the helper pte_mkhuge(). arm64 override for arch_make_huge_pte() calls pte_mkhuge() internally, thus creating an impression, that both of these callbacks are being used in core HugeTLB and hence required to be defined. This drops off pte_mkhuge() which was never required to begin with as there could not be any section mappings at the PTE level. Re-organize arch_make_huge_pte() based on requested page size and create the entry for the applicable page table level as needed. It also removes a redundancy of clearing PTE_TABLE_BIT bit followed by setting both PTE_TABLE_BIT and PTE_VALID bits (via PTE_TYPE_MASK) in the pte, while creating CONT_PTE_SIZE size entries. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> --- This applies on v6.12-rc5 arch/arm64/include/asm/pgtable.h | 5 ----- arch/arm64/mm/hugetlbpage.c | 21 ++++++++++++++++----- 2 files changed, 16 insertions(+), 10 deletions(-)