On 06/16/22 at 11:34am, Baolin Wang wrote: > The HugeTLB address ranges are linearly scanned during fork, unmap and > remap operations, and the linear scan can skip to the end of range mapped > by the page table page if hitting a non-present entry, which can help > to speed linear scanning of the HugeTLB address ranges. > > So hugetlb_mask_last_hp() is introduced to help to update the address in > the loop of HugeTLB linear scanning with getting the last huge page mapped > by the associated page table page[1], when a non-present entry is encountered. > > Considering ARM64 specific cont-pte/pmd size HugeTLB, this patch implemented > an ARM64 specific hugetlb_mask_last_hp() to help this case. > > [1] https://lore.kernel.org/linux-mm/20220527225849.284839-1-mike.kravetz@xxxxxxxxxx/ > > Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> > --- > Note: this patch is based on the series: "hugetlb: speed up linear > address scanning" from Mike. Mike, please fold it into your series. > Thanks. > --- > arch/arm64/mm/hugetlbpage.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c > index e2a5ec9..958935c 100644 > --- a/arch/arm64/mm/hugetlbpage.c > +++ b/arch/arm64/mm/hugetlbpage.c > @@ -368,6 +368,26 @@ pte_t *huge_pte_offset(struct mm_struct *mm, > return NULL; > } > > +unsigned long hugetlb_mask_last_hp(struct hstate *h) > +{ > + unsigned long hp_size = huge_page_size(h); hp_size may not be a good name, it reminds me of hotplug. I would name it hpage_size even though a little more characters are added. > + > + switch (hp_size) { > + case PUD_SIZE: > + return PGDIR_SIZE - PUD_SIZE; > + case CONT_PMD_SIZE: > + return PUD_SIZE - CONT_PMD_SIZE; > + case PMD_SIZE: > + return PUD_SIZE - PMD_SIZE; > + case CONT_PTE_SIZE: > + return PMD_SIZE - CONT_PTE_SIZE; > + default: > + break; > + } > + > + return ~0UL; > +} > + > pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags) > { > size_t pagesize = 1UL << shift; > -- > 1.8.3.1 > >
