+
+/**
+ * calc_order - Determine the order of allocation needed for pagedir_save.
+ *
+ * This looks tricky, but is just subtle. Please fix it some time.
+ * Since there are %nr_copy_pages worth of pages in the snapshot, we need
+ * to allocate enough contiguous space to hold
+ * (%nr_copy_pages * sizeof(struct pbe)),
+ * which has the saved/orig locations of the page..
+ *
+ * SUSPEND_PD_PAGES() tells us how many pages we need to hold those
+ * structures, then we call get_bitmask_order(), which will tell us the
+ * last bit set in the number, starting with 1. (If we need 30 pages, that
+ * is 0x0000001e in hex. The last bit is the 5th, which is the order we
+ * would use to allocate 32 contiguous pages).
+ *
+ * Since we also need to save those pages, we add the number of pages that
+ * we need to nr_copy_pages, and in case of an overflow, do the
+ * calculation again to update the number of pages needed.
+ *
+ * With this model, we will tend to waste a lot of memory if we just cross
+ * an order boundary. Plus, the higher the order of allocation that we try
+ * to do, the more likely we are to fail in a low-memory situtation
+ * (though we're unlikely to get this far in such a case, since swsusp
+ * requires half of memory to be free anyway).
+ */
+
+
+static void calc_order(void)