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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2015-05-05 16:23:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-05-05 17:10:10 -0700
commit602498f9aa43d4951eece3fd6ad95a6d0a78d537 (patch)
tree0cf960b93d33ac4f3d27c6dd5b5af3856f7eadae /mm/memory-failure.c
parent4d61ff6b9960cb00cf2c12abd5769aa2dd475415 (diff)
downloadlinux-602498f9aa43d4951eece3fd6ad95a6d0a78d537.tar.gz
mm: soft-offline: fix num_poisoned_pages counting on concurrent events
If multiple soft offline events hit one free page/hugepage concurrently,
soft_offline_page() can handle the free page/hugepage multiple times,
which makes num_poisoned_pages counter increased more than once.  This
patch fixes this wrong counting by checking TestSetPageHWPoison for normal
papes and by checking the return value of dequeue_hwpoisoned_huge_page()
for hugepages.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Dean Nelson <dnelson@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: <stable@vger.kernel.org>	[3.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 22e0f270e4f7..501820c815b3 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1777,12 +1777,12 @@ int soft_offline_page(struct page *page, int flags)
 	} else if (ret == 0) { /* for free pages */
 		if (PageHuge(page)) {
 			set_page_hwpoison_huge_page(hpage);
-			dequeue_hwpoisoned_huge_page(hpage);
-			atomic_long_add(1 << compound_order(hpage),
+			if (!dequeue_hwpoisoned_huge_page(hpage))
+				atomic_long_add(1 << compound_order(hpage),
 					&num_poisoned_pages);
 		} else {
-			SetPageHWPoison(page);
-			atomic_long_inc(&num_poisoned_pages);
+			if (!TestSetPageHWPoison(page))
+				atomic_long_inc(&num_poisoned_pages);
 		}
 	}
 	unset_migratetype_isolate(page, MIGRATE_MOVABLE);