[PATCH v9 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid()

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(), if pfn and pfn+1 are in the same memblock region, we can record the last returned memblock

[PATCH v9 6/6] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid()

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(), if pfn and pfn+1 are in the same memblock region, we can record the last returned memblock