mm: introduce dump_page() and print symbolic flag names

- introduce dump_page() to print the page info for debugging some error
  condition.

- convert three mm users: bad_page(), print_bad_pte() and memory offline
  failure.

- print an extra field: the symbolic names of page->flags

Example dump_page() output:

[  157.521694] page:ffffea0000a7cba8 count:2 mapcount:1 mapping:ffff88001c901791 index:0x147
[  157.525570] page flags: 0x100000000100068(uptodate|lru|active|swapbacked)

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alex Chiang <achiang@hp.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mel Gorman <mel@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 3d9130bd95d0..5b7f2002e54b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -509,12 +509,8 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
                 "BUG: Bad page map in process %s  pte:%08llx pmd:%08llx\n",
                 current->comm,
                 (long long)pte_val(pte), (long long)pmd_val(*pmd));
-        if (page) {
-                printk(KERN_ALERT
-                "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
-                page, (void *)page->flags, page_count(page),
-                page_mapcount(page), page->mapping, page->index);
-        }
+        if (page)
+                dump_page(page);
         printk(KERN_ALERT
                 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
                 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);