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>
This commit is contained in:
Naoya Horiguchi 2015-05-05 16:23:46 -07:00 committed by Linus Torvalds
parent 4d61ff6b99
commit 602498f9aa

View File

@ -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);