mm/mm_init.c: remove unneeded calc_memmap_size()

Nobody calls calc_memmap_size() now.

Link: https://lkml.kernel.org/r/20240325145646.1044760-6-bhe@redhat.comSigned-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mm_init.c

@@ -1332,26 +1332,6 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
 	pr_debug("On node %d totalpages: %lu\n", pgdat->node_id, realtotalpages);
 }
 
-static unsigned long __init calc_memmap_size(unsigned long spanned_pages,
-						unsigned long present_pages)
-{
-	unsigned long pages = spanned_pages;
-
-	/*
-	 * Provide a more accurate estimation if there are holes within
-	 * the zone and SPARSEMEM is in use. If there are holes within the
-	 * zone, each populated memory region may cost us one or two extra
-	 * memmap pages due to alignment because memmap pages for each
-	 * populated regions may not be naturally aligned on page boundary.
-	 * So the (present_pages >> 4) heuristic is a tradeoff for that.
-	 */
-	if (spanned_pages > present_pages + (present_pages >> 4) &&
-	    IS_ENABLED(CONFIG_SPARSEMEM))
-		pages = present_pages;
-
-	return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
-}
-
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 static void pgdat_init_split_queue(struct pglist_data *pgdat)
 {