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.Signed-off-by: Jia He <[email protected]> --- include/linux/memblock.h | 3 +-- mm/memblock.c | 23 +++++++++++++++++++---- mm/page_alloc.c | 3 ++- 3 files changed, 22 insertions(+), 7 deletions(-) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index b7aa3ff..9471db4 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -203,8 +203,7 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn, i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid)) #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ -unsigned long memblock_next_valid_pfn(unsigned long pfn); - +unsigned long memblock_next_valid_pfn(unsigned long pfn, int *last_idx); /** * for_each_free_mem_range - iterate through free memblock areas * @i: u64 used as loop variable diff --git a/mm/memblock.c b/mm/memblock.c index c87924d..a9e8da4 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1133,13 +1133,26 @@ int __init_memblock memblock_set_node(phys_addr_t base, phys_addr_t size, } #endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ -unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn) +unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn, + int *last_idx) { struct memblock_type *type = &memblock.memory; unsigned int right = type->cnt; unsigned int mid, left = 0; + unsigned long start_pfn, end_pfn; phys_addr_t addr = PFN_PHYS(++pfn); + /* fast path, return pfh+1 if next pfn is in the same region */ + if (*last_idx != -1) { + start_pfn = PFN_DOWN(type->regions[*last_idx].base); + end_pfn = PFN_DOWN(type->regions[*last_idx].base + + type->regions[*last_idx].size); + + if (pfn < end_pfn && pfn > start_pfn) + return pfn; + } + + /* slow path, do the binary searching */ do { mid = (right + left) / 2; @@ -1149,15 +1162,17 @@ unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn) type->regions[mid].size)) left = mid + 1; else { - /* addr is within the region, so pfn is valid */ + *last_idx = mid; return pfn; } } while (left < right); if (right == type->cnt) return -1UL; - else - return PHYS_PFN(type->regions[right].base); + + *last_idx = right; + + return PHYS_PFN(type->regions[*last_idx].base); } static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size, diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 3899209..f28c62c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5456,6 +5456,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, unsigned long end_pfn = start_pfn + size; pg_data_t *pgdat = NODE_DATA(nid); unsigned long pfn; + int idx = -1; unsigned long nr_initialised = 0; struct page *page; #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP @@ -5487,7 +5488,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, * end_pfn), such that we hit a valid pfn (or end_pfn) * on our next iteration of the loop. */ - pfn = memblock_next_valid_pfn(pfn) - 1; + pfn = memblock_next_valid_pfn(pfn, &idx) - 1; #endif continue; } -- 2.7.4
