On Thu, Jun 16, 2022 at 02:05:15PM -0700, Mike Kravetz wrote: > HugeTLB address ranges are linearly scanned during fork, unmap and > remap operations. If a non-present entry is encountered, the code > currently continues to the next huge page aligned address. However, > a non-present entry implies that the page table page for that entry > is not present. Therefore, the linear scan can skip to the end of > range mapped by the page table page. This can speed operations on > large sparsely populated hugetlb mappings. > > Create a new routine hugetlb_mask_last_page() that will return an > address mask. When the mask is ORed with an address, the result > will be the address of the last huge page mapped by the associated > page table page. Use this mask to update addresses in routines which > linearly scan hugetlb address ranges when a non-present pte is > encountered. > > hugetlb_mask_last_page is related to the implementation of > huge_pte_offset as hugetlb_mask_last_page is called when huge_pte_offset > returns NULL. This patch only provides a complete hugetlb_mask_last_page > implementation when CONFIG_ARCH_WANT_GENERAL_HUGETLB is defined. > Architectures which provide their own versions of huge_pte_offset can also > provide their own version of hugetlb_mask_last_page. > > Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > Tested-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> > Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> It'll be more efficient, Thanks. Acked-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
