From: Jia He <[email protected]> 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. in early_pfn_valid(), we can record the last returned memblock region. If current pfn and last pfn are in the same memory region, we needn't do the unnecessary binary searches because memblock_is_nomap is the same result for whole memory region.
Signed-off-by: Jia He <[email protected]> --- mm/memblock.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/mm/memblock.c b/mm/memblock.c index c783b1a..274bd9f 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1188,6 +1188,30 @@ ulong __init_memblock memblock_next_valid_pfn(ulong pfn) return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); + +int pfn_valid_region(ulong pfn) +{ + ulong start_pfn, end_pfn; + struct memblock_type *type = &memblock.memory; + struct memblock_region *regions = type->regions; + + 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 !memblock_is_nomap( + ®ions[early_region_idx]); + } + + early_region_idx = memblock_search_pfn_regions(pfn); + if (early_region_idx == -1) + return false; + + return !memblock_is_nomap(®ions[early_region_idx]); +} +EXPORT_SYMBOL(pfn_valid_region); #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, -- 1.8.3.1
