From ec393a0f014eaf688a3dbe8c8a4cbb52d7f535f9 Mon Sep 17 00:00:00 2001 From: Pavel Tatashin Date: Fri, 26 Oct 2018 15:10:21 -0700 Subject: mm: return zero_resv_unavail optimization When checking for valid pfns in zero_resv_unavail(), it is not necessary to verify that pfns within pageblock_nr_pages ranges are valid, only the first one needs to be checked. This is because memory for pages are allocated in contiguous chunks that contain pageblock_nr_pages struct pages. Link: http://lkml.kernel.org/r/20181002143821.5112-3-msys.mizuma@gmail.com Signed-off-by: Pavel Tatashin Signed-off-by: Masayoshi Mizuma Reviewed-by: Masayoshi Mizuma Acked-by: Naoya Horiguchi Reviewed-by: Oscar Salvador Cc: Ingo Molnar Cc: Michal Hocko Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 46 ++++++++++++++++++++++++++-------------------- 1 file changed, 26 insertions(+), 20 deletions(-) (limited to 'mm/page_alloc.c') diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6d863c5afa08..863d46da6586 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6509,6 +6509,29 @@ void __init free_area_init_node(int nid, unsigned long *zones_size, } #if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP) + +/* + * Zero all valid struct pages in range [spfn, epfn), return number of struct + * pages zeroed + */ +static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn) +{ + unsigned long pfn; + u64 pgcnt = 0; + + for (pfn = spfn; pfn < epfn; pfn++) { + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) { + pfn = ALIGN_DOWN(pfn, pageblock_nr_pages) + + pageblock_nr_pages - 1; + continue; + } + mm_zero_struct_page(pfn_to_page(pfn)); + pgcnt++; + } + + return pgcnt; +} + /* * Only struct pages that are backed by physical memory are zeroed and * initialized by going through __init_single_page(). But, there are some @@ -6524,7 +6547,6 @@ void __init free_area_init_node(int nid, unsigned long *zones_size, void __init zero_resv_unavail(void) { phys_addr_t start, end; - unsigned long pfn; u64 i, pgcnt; phys_addr_t next = 0; @@ -6534,34 +6556,18 @@ void __init zero_resv_unavail(void) pgcnt = 0; for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) { - if (next < start) { - for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) { - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) - continue; - mm_zero_struct_page(pfn_to_page(pfn)); - pgcnt++; - } - } + if (next < start) + pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start)); next = end; } - for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) { - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) - continue; - mm_zero_struct_page(pfn_to_page(pfn)); - pgcnt++; - } - + pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn); /* * Struct pages that do not have backing memory. This could be because * firmware is using some of this memory, or for some other reasons. - * Once memblock is changed so such behaviour is not allowed: i.e. - * list of "reserved" memory must be a subset of list of "memory", then - * this code can be removed. */ if (pgcnt) pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt); - } #endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */ -- cgit v1.2.3