From 4db0e950c5b78586bea9e1b027be849631f89a17 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Fri, 22 Feb 2013 16:34:05 -0800 Subject: [PATCH] mm/memory-failure.c: fix wrong num_poisoned_pages in handling memory error on thp num_poisoned_pages counts up the number of pages isolated by memory errors. But for thp, only one subpage is isolated because memory error handler splits it, so it's wrong to add (1 << compound_trans_order). [akpm@linux-foundation.org: tweak comment] Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Cc: Tony Luck Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 9cab165fd668..1a56d63adf9c 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1039,7 +1039,17 @@ int memory_failure(unsigned long pfn, int trapno, int flags) return 0; } - nr_pages = 1 << compound_trans_order(hpage); + /* + * Currently errors on hugetlbfs pages are measured in hugepage units, + * so nr_pages should be 1 << compound_order. OTOH when errors are on + * transparent hugepages, they are supposed to be split and error + * measurement is done in normal page units. So nr_pages should be one + * in this case. + */ + if (PageHuge(p)) + nr_pages = 1 << compound_order(hpage); + else /* normal page or thp */ + nr_pages = 1; atomic_long_add(nr_pages, &num_poisoned_pages); /* -- 2.30.2