mm: print more details for bad_page()

bad_page() is cool in that it prints out a bunch of data about the page.
But, I can never remember which page flags are good and which are bad,
or whether ->index or ->mapping is required to be NULL.

This patch allows bad/dump_page() callers to specify a string about why
they are dumping the page and adds explanation strings to a number of
places.  It also adds a 'bad_flags' argument to bad_page(), which it
then dumps out separately from the flags which are actually set.

This way, the messages will show specifically why the page was bad,
*specifically* which flags it is complaining about, if it was a page
flag combination which was the problem.

[akpm@linux-foundation.org: switch to pr_alert]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 86487df..71d70c0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -671,7 +671,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
 		current->comm,
 		(long long)pte_val(pte), (long long)pmd_val(*pmd));
 	if (page)
-		dump_page(page);
+		dump_page(page, "bad pte");
 	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);