[PATCH] swsusp: take lowmem reserves into account

swsusp allocates memory from the normal zone, so it cannot use lowmem
reserve pages from the lower zones.  Therefore it should not count these
pages as available to it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/power/swsusp.c

@@ -188,8 +188,10 @@ int swsusp_shrink_memory(void)
 			PAGES_FOR_IO;
 		tmp = size;
 		for_each_zone (zone)
-			if (!is_highmem(zone))
+			if (!is_highmem(zone) && populated_zone(zone)) {
 				tmp -= zone->free_pages;
+				tmp += zone->lowmem_reserve[ZONE_NORMAL];
+			}
 		if (tmp > 0) {
 			tmp = __shrink_memory(tmp);
 			if (!tmp)