From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxx>
Acked-by: Dean Nelson <dnelson@xxxxxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [3.14+]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory-failure.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff -puN mm/memory-failure.c~mm-soft-offline-fix-num_poisoned_pages-counting-on-concurrent-events mm/memory-failure.c
--- a/mm/memory-failure.c~mm-soft-offline-fix-num_poisoned_pages-counting-on-concurrent-events
+++ a/mm/memory-failure.c
@@ -1777,12 +1777,12 @@ int soft_offline_page(struct page *page,
} 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);
_
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