Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [13/31] HWPOISON: detect free buddy pages explicitly | Date | Tue, 8 Dec 2009 22:16:29 +0100 (CET) |
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From: Wu Fengguang <fengguang.wu@intel.com>
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>
--- mm/internal.h | 3 +++ mm/memory-failure.c | 9 +++++++-- mm/page_alloc.c | 21 +++++++++++++++++++++ 3 files changed, 31 insertions(+), 2 deletions(-)
Index: linux/mm/memory-failure.c =================================================================== --- linux.orig/mm/memory-failure.c +++ linux/mm/memory-failure.c @@ -809,8 +809,13 @@ int __memory_failure(unsigned long pfn, */ if (!(flags & MF_COUNT_INCREASED) && !get_page_unless_zero(compound_head(p))) { - action_result(pfn, "free or high order kernel", IGNORED); - return PageBuddy(compound_head(p)) ? 0 : -EBUSY; + if (is_free_buddy_page(p)) { + action_result(pfn, "free buddy", DELAYED); + return 0; + } else { + action_result(pfn, "high order kernel", IGNORED); + return -EBUSY; + } } /* Index: linux/mm/internal.h =================================================================== --- linux.orig/mm/internal.h +++ linux/mm/internal.h @@ -50,6 +50,9 @@ extern void putback_lru_page(struct page */ extern void __free_pages_bootmem(struct page *page, unsigned int order); extern void prep_compound_page(struct page *page, unsigned long order); +#ifdef CONFIG_MEMORY_FAILURE +extern bool is_free_buddy_page(struct page *page); +#endif /* Index: linux/mm/page_alloc.c =================================================================== --- linux.orig/mm/page_alloc.c +++ linux/mm/page_alloc.c @@ -5085,3 +5085,24 @@ __offline_isolated_pages(unsigned long s 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
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