[PATCH] mm/page_alloc:Check pfn valid once in every page blocks

[skseofh <skseofh@gmail.com>]

Hi, all

Please check the patch below.
Thanks:)


No need to check validity for every pfn in [spfn, epfn).
---
 mm/page_alloc.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 174c849ba9f2..212460c9fe0f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6936,11 +6936,19 @@ void __init free_area_init_memoryless_node(int nid)
  */
 static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
 {
-	unsigned long pfn;
+	unsigned long pfn, block_pfn;
 	u64 pgcnt = 0;
+	bool in_block = 0;
+
+	block_pfn = ALIGN_DOWN(spfn, pageblock_nr_pages);
 
 	for (pfn = spfn; pfn < epfn; pfn++) {
-		if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
+		if (block_pfn != ALIGN_DOWN(pfn, pageblock_nr_pages)) {
+			block_pfn = ALIGN_DOWN(pfn, pageblock_nr_pages);
+			in_block = 0;
+		}
+
+		if (!in_block && !pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
 			pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
 				+ pageblock_nr_pages - 1;
 			continue;
@@ -6953,6 +6961,7 @@ static u64 __init init_unavailable_range(unsigned long spfn, unsigned long epfn)
 		__init_single_page(pfn_to_page(pfn), pfn, 0, 0);
 		__SetPageReserved(pfn_to_page(pfn));
 		pgcnt++;
+		in_block = 1;
 	}
 
 	return pgcnt;
-- 
2.17.1