| From 7f9e116273aa43e0be7574380a03b9606aba9660 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 26 Oct 2018 15:10:21 -0700 |
| Subject: mm: return zero_resv_unavail optimization |
| |
| From: Pavel Tatashin <pavel.tatashin@microsoft.com> |
| |
| [ Upstream commit ec393a0f014eaf688a3dbe8c8a4cbb52d7f535f9 ] |
| |
| 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 <pavel.tatashin@microsoft.com> |
| Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> |
| Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> |
| Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> |
| Reviewed-by: Oscar Salvador <osalvador@suse.de> |
| Cc: Ingo Molnar <mingo@kernel.org> |
| Cc: Michal Hocko <mhocko@kernel.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| mm/page_alloc.c | 46 ++++++++++++++++++++++++++-------------------- |
| 1 file changed, 26 insertions(+), 20 deletions(-) |
| |
| diff --git a/mm/page_alloc.c b/mm/page_alloc.c |
| index 19f2e77d1c50b..8a00c32191263 100644 |
| --- a/mm/page_alloc.c |
| +++ b/mm/page_alloc.c |
| @@ -6456,6 +6456,29 @@ 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 |
| @@ -6471,7 +6494,6 @@ 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; |
| |
| @@ -6481,34 +6503,18 @@ 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 */ |
| |
| -- |
| 2.20.1 |
| |