diff options
| author | Wu Fengguang <fengguang.wu@intel.com> | 2009-12-16 12:19:58 +0100 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2009-12-16 12:19:58 +0100 |
| commit | 8d22ba1b74aa9420b6032d856446564fb21f8090 (patch) | |
| tree | 6c2e2d27e81d784faa0481500f1cecc613ff1167 /mm/page_alloc.c | |
| parent | 95d01fc664b9476e0d18e3d745bb209a42a33588 (diff) | |
| download | lwn-8d22ba1b74aa9420b6032d856446564fb21f8090.tar.gz lwn-8d22ba1b74aa9420b6032d856446564fb21f8090.zip | |
HWPOISON: detect free buddy pages explicitly
Most free pages in the buddy system have no PG_buddy set.
Introduce is_free_buddy_page() for detecting them reliably.
CC: Nick Piggin <npiggin@suse.de>
CC: Mel Gorman <mel@linux.vnet.ibm.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 59d2e88fb47c..6867b4d391fd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5081,3 +5081,24 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) spin_unlock_irqrestore(&zone->lock, flags); } #endif + +#ifdef CONFIG_MEMORY_FAILURE +bool is_free_buddy_page(struct page *page) +{ + struct zone *zone = page_zone(page); + unsigned long pfn = page_to_pfn(page); + unsigned long flags; + int order; + + spin_lock_irqsave(&zone->lock, flags); + for (order = 0; order < MAX_ORDER; order++) { + struct page *page_head = page - (pfn & ((1 << order) - 1)); + + if (PageBuddy(page_head) && page_order(page_head) >= order) + break; + } + spin_unlock_irqrestore(&zone->lock, flags); + + return order < MAX_ORDER; +} +#endif |