Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") tried to optimize the loop in memmap_init_zone(). But there is still some room for improvement. Patch 1 introduce new config to make codes more generic Patch 2 remain the memblock_next_valid_pfn on arm and arm64 Patch 3 optimizes the memblock_next_valid_pfn() Patch 4~6 optimizes the early_pfn_valid() As for the performance improvement, after this set, I can see the time overhead of memmap_init() is reduced from 27956us to 13537us in my armv8a server(QDF2400 with 96G memory, pagesize 64k). Attached the memblock region information in my server. [ 0.000000] Zone ranges: [ 0.000000] DMA32 [mem 0x0000000000200000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x00000017ffffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000000200000-0x000000000021ffff] [ 0.000000] node 0: [mem 0x0000000000820000-0x000000000307ffff] [ 0.000000] node 0: [mem 0x0000000003080000-0x000000000308ffff] [ 0.000000] node 0: [mem 0x0000000003090000-0x00000000031fffff] [ 0.000000] node 0: [mem 0x0000000003200000-0x00000000033fffff] [ 0.000000] node 0: [mem 0x0000000003410000-0x00000000034fffff] [ 0.000000] node 0: [mem 0x0000000003500000-0x000000000351ffff] [ 0.000000] node 0: [mem 0x0000000003520000-0x000000000353ffff] [ 0.000000] node 0: [mem 0x0000000003540000-0x0000000003e3ffff] [ 0.000000] node 0: [mem 0x0000000003e40000-0x0000000003e7ffff] [ 0.000000] node 0: [mem 0x0000000003e80000-0x0000000003ecffff] [ 0.000000] node 0: [mem 0x0000000003ed0000-0x0000000003ed5fff] [ 0.000000] node 0: [mem 0x0000000003ed6000-0x0000000006eeafff] [ 0.000000] node 0: [mem 0x0000000006eeb000-0x000000000710ffff] [ 0.000000] node 0: [mem 0x0000000007110000-0x0000000007f0ffff] [ 0.000000] node 0: [mem 0x0000000007f10000-0x0000000007faffff] [ 0.000000] node 0: [mem 0x0000000007fb0000-0x000000000806ffff] [ 0.000000] node 0: [mem 0x0000000008070000-0x00000000080affff] [ 0.000000] node 0: [mem 0x00000000080b0000-0x000000000832ffff] [ 0.000000] node 0: [mem 0x0000000008330000-0x000000000836ffff] [ 0.000000] node 0: [mem 0x0000000008370000-0x000000000838ffff] [ 0.000000] node 0: [mem 0x0000000008390000-0x00000000083a9fff] [ 0.000000] node 0: [mem 0x00000000083aa000-0x00000000083bbfff] [ 0.000000] node 0: [mem 0x00000000083bc000-0x00000000083fffff] [ 0.000000] node 0: [mem 0x0000000008400000-0x000000000841ffff] [ 0.000000] node 0: [mem 0x0000000008420000-0x000000000843ffff] [ 0.000000] node 0: [mem 0x0000000008440000-0x000000000865ffff] [ 0.000000] node 0: [mem 0x0000000008660000-0x000000000869ffff] [ 0.000000] node 0: [mem 0x00000000086a0000-0x00000000086affff] [ 0.000000] node 0: [mem 0x00000000086b0000-0x00000000086effff] [ 0.000000] node 0: [mem 0x00000000086f0000-0x0000000008b6ffff] [ 0.000000] node 0: [mem 0x0000000008b70000-0x0000000008bbffff] [ 0.000000] node 0: [mem 0x0000000008bc0000-0x0000000008edffff] [ 0.000000] node 0: [mem 0x0000000008ee0000-0x0000000008ee0fff] [ 0.000000] node 0: [mem 0x0000000008ee1000-0x0000000008ee2fff] [ 0.000000] node 0: [mem 0x0000000008ee3000-0x000000000decffff] [ 0.000000] node 0: [mem 0x000000000ded0000-0x000000000defffff] [ 0.000000] node 0: [mem 0x000000000df00000-0x000000000fffffff] [ 0.000000] node 0: [mem 0x0000000010800000-0x0000000017feffff] [ 0.000000] node 0: [mem 0x000000001c000000-0x000000001c00ffff] [ 0.000000] node 0: [mem 0x000000001c010000-0x000000001c7fffff] [ 0.000000] node 0: [mem 0x000000001c810000-0x000000007efbffff] [ 0.000000] node 0: [mem 0x000000007efc0000-0x000000007efdffff] [ 0.000000] node 0: [mem 0x000000007efe0000-0x000000007efeffff] [ 0.000000] node 0: [mem 0x000000007eff0000-0x000000007effffff] [ 0.000000] node 0: [mem 0x000000007f000000-0x00000017ffffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000000200000-0x00000017ffffffff] [ 0.000000] On node 0 totalpages: 25145296 [ 0.000000] DMA32 zone: 16376 pages used for memmap [ 0.000000] DMA32 zone: 0 pages reserved [ 0.000000] DMA32 zone: 1028048 pages, LIFO batch:31 [ 0.000000] Normal zone: 376832 pages used for memmap [ 0.000000] Normal zone: 24117248 pages, LIFO batch:31 Changelog: V9: - rebase to mmotm master, refine the log description. No major changes V8: - introduce new config and move generic code to early_pfn.h - optimize memblock_next_valid_pfn as suggested by Matthew Wilcox V7: - fix i386 compilation error. refine the commit description V6: - simplify the codes, move arm/arm64 common codes to one file. - refine patches as suggested by Danial Vacek and Ard Biesheuvel V5: - further refining as suggested by Danial Vacek. Make codes arm/arm64 more arch specific V4: - refine patches as suggested by Danial Vacek and Wei Yang - optimized on arm besides arm64 V3: - fix 2 issues reported by kbuild test robot V2: - rebase to mmotm latest - remain memblock_next_valid_pfn on arm64 - refine memblock_search_pfn_regions and pfn_valid_region Jia He (6): arm: arm64: introduce CONFIG_HAVE_MEMBLOCK_PFN_VALID mm: page_alloc: remain memblock_next_valid_pfn() on arm/arm64 arm: arm64: page_alloc: reduce unnecessary binary search in memblock_next_valid_pfn() mm/memblock: introduce memblock_search_pfn_regions() arm: arm64: introduce pfn_valid_region() mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() arch/arm/Kconfig | 4 +++ arch/arm/mm/init.c | 1 + arch/arm64/Kconfig | 4 +++ arch/arm64/mm/init.c | 1 + include/linux/early_pfn.h | 79 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/memblock.h | 2 ++ include/linux/mmzone.h | 18 ++++++++++- mm/Kconfig | 3 ++ mm/memblock.c | 9 ++++++ mm/page_alloc.c | 5 ++- 10 files changed, 124 insertions(+), 2 deletions(-) create mode 100644 include/linux/early_pfn.h -- 1.8.3.1