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HWPOISON: detect free buddy pages explicitly

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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>
This commit is contained in:
Wu Fengguang 2009-12-16 12:19:58 +01:00 committed by Andi Kleen
parent 95d01fc664
commit 8d22ba1b74
3 changed files with 31 additions and 2 deletions
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3
mm/internal.h
View file

@ -50,6 +50,9 @@ extern void putback_lru_page(struct page *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
/*

9
mm/memory-failure.c
View file

@ -807,8 +807,13 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
*/
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;
}
}
/*

21
mm/page_alloc.c
View file

@ -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