At unmap, fork and remap time hugetlb address ranges are linearly scanned. We can optimize these scans if the ranges are sparsely populated. Also, enable page table "Lazy copy" for hugetlb at fork. NOTE: Architectures not defining CONFIG_ARCH_WANT_GENERAL_HUGETLB need to add an arch specific version hugetlb_mask_last_page() to take advantage of sparse address scanning improvements. Baolin Wang added the routine for arm64. Other architectures which could be optimized are: ia64, mips, parisc, powerpc, s390, sh and sparc. Baolin Wang (1): arm64/hugetlb: Implement arm64 specific hugetlb_mask_last_page Mike Kravetz (3): hugetlb: skip to end of PT page mapping when pte not present hugetlb: do not update address in huge_pmd_unshare hugetlb: Lazy page table copies in fork() arch/arm64/mm/hugetlbpage.c | 20 +++++++ include/linux/hugetlb.h | 5 +- mm/hugetlb.c | 109 +++++++++++++++++++++++++----------- mm/memory.c | 2 +- mm/rmap.c | 4 +- 5 files changed, 103 insertions(+), 37 deletions(-) -- 2.35.3
