From 85a450f9802c17cffbc2e1f32462b9cb64944ce4 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= Date: Wed, 18 Mar 2009 17:27:31 -0700 Subject: [PATCH] mm: Check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE This fixes a problem where the first pageblock got marked MIGRATE_RESERVE even though it only had a few free pages. This in turn caused no contiguous memory to be reserved and frequent kswapd wakeups that emptied the caches to get more contiguous memory. --- mm/page_alloc.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 17ce3faeecca..d0e56c880154 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3159,6 +3159,20 @@ static inline unsigned long wait_table_bits(unsigned long size) #define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1)) +/* + * Check if a pageblock contains reserved pages + */ +static int pageblock_is_reserved(unsigned long start_pfn) +{ + unsigned long end_pfn = start_pfn + pageblock_nr_pages; + unsigned long pfn; + + for (pfn = start_pfn; pfn < end_pfn; pfn++) + if (PageReserved(pfn_to_page(pfn))) + return 1; + return 0; +} + /* * Mark a number of pageblocks as MIGRATE_RESERVE. The number * of blocks reserved is based on min_wmark_pages(zone). The memory within @@ -3198,7 +3212,7 @@ static void setup_zone_migrate_reserve(struct zone *zone) continue; /* Blocks with reserved pages will never free, skip them. */ - if (PageReserved(page)) + if (pageblock_is_reserved(pfn)) continue; block_migratetype = get_pageblock_migratetype(page); -- 2.34.1