Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
where possible") optimized the loop in memmap_init_zone(). But there is
still some room for improvement.E.g. if pfn and pfn+1 are in the same memblock region, we can simply pfn++ instead of doing the binary search in memblock_next_valid_pfn. Furthermore, if the pfn is in a gap of two memory region, skip to next region directly if possible. 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 Signed-off-by: Jia He <[email protected]> Reviewed-by: Pavel Tatashin <[email protected]> --- mm/memblock.c | 33 +++++++++++++++++++++++++++------ 1 file changed, 27 insertions(+), 6 deletions(-) diff --git a/mm/memblock.c b/mm/memblock.c index 077ca62..46cb6be 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1144,28 +1144,49 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size, unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn) { struct memblock_type *type = &memblock.memory; + struct memblock_region *regions = type->regions; unsigned int right = type->cnt; unsigned int mid, left = 0; + unsigned long start_pfn, end_pfn, next_start_pfn; phys_addr_t addr = PFN_PHYS(++pfn); + static int early_region_idx __initdata_memblock = -1; + /* fast path, return pfn+1 if next pfn is in the same region */ + if (early_region_idx != -1) { + start_pfn = PFN_DOWN(regions[early_region_idx].base); + end_pfn = PFN_DOWN(regions[early_region_idx].base + + regions[early_region_idx].size); + + if (pfn >= start_pfn && pfn < end_pfn) + return pfn; + + early_region_idx++; + next_start_pfn = PFN_DOWN(regions[early_region_idx].base); + + if (pfn >= end_pfn && pfn <= next_start_pfn) + return next_start_pfn; + } + + /* slow path, do the binary searching */ do { mid = (right + left) / 2; - if (addr < type->regions[mid].base) + if (addr < regions[mid].base) right = mid; - else if (addr >= (type->regions[mid].base + - type->regions[mid].size)) + else if (addr >= (regions[mid].base + regions[mid].size)) left = mid + 1; else { - /* addr is within the region, so pfn is valid */ + early_region_idx = mid; return pfn; } } while (left < right); if (right == type->cnt) return -1UL; - else - return PHYS_PFN(type->regions[right].base); + + early_region_idx = right; + + return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/ -- 1.8.3.1
