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_hotplug.c b/mm/memory_hotplug.c
index cc2ab37220b7..a512a47241a4 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1309,7 +1309,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 #ifdef CONFIG_DEBUG_VM
                         printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
                                pfn);
-                        dump_page(page);
+                        dump_page(page, "failed to remove from LRU");
 #endif
                         put_page(page);
                         /* Because we don't have big zone->lock. we should