PM/Hibernate: do not count debug pages as savable

When debugging with CONFIG_DEBUG_PAGEALLOC and debug_guardpage_minorder >
0, we have lot of free pages that are not marked so.  Snapshot code
account them as savable, what cause hibernate memory preallocation
failure.

It is pretty hard to make hibernate allocation succeed with
debug_guardpage_minorder=1.  This change at least make it possible when
system has relatively big amount of RAM.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 8018450517a9b1f3a33763be9341fadfae25c259..383c637aa25ac03aee64e6cb8413918754aba055 100644 (file)
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -858,6 +858,9 @@ static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
            PageReserved(page))
                return NULL;
 
+       if (page_is_guard(page))
+               return NULL;
+
        return page;
 }
 
@@ -920,6 +923,9 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn)
            && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
                return NULL;
 
+       if (page_is_guard(page))
+               return NULL;
+
        return page;
 }