From 8d22ba1b74aa9420b6032d856446564fb21f8090 Mon Sep 17 00:00:00 2001
From: Wu Fengguang <fengguang.wu@intel.com>
Date: Wed, 16 Dec 2009 12:19:58 +0100
Subject: 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>
---
 mm/memory-failure.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

(limited to 'mm/memory-failure.c')

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 676ab394200..5055b940df5 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -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;
+		}
 	}
 
 	/*
-- 
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