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). [[email protected]: tweak comment] Signed-off-by: Naoya Horiguchi <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Tony Luck <[email protected]> Cc: Wu Fengguang <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
progmanos · Feb 24, 2013 · 4db0e95 · 4db0e95
1 parent af8fae7
commit 4db0e95
Showing 1 changed file with 11 additions and 1 deletion.
diff --git 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);
 
 	/*