[PATCH] do_no_page() rss accounting fix

From: Jaroslav Kysela <perex@suse.cz>

The do_no_page() function in mm/memory.c does accounting for reserved pages
(++mm->rss), but in zap_pte_range() we don't decrement rss if the page was
reserved.

So don't account for PageReserved pages in the rss.  (Maybe it would be
better to fix zap_pte_range in the opposite direction..)

mm/memory.c

@@ -1459,7 +1459,8 @@ do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	 */
 	/* Only go through if we didn't race with anybody else... */
 	if (pte_none(*page_table)) {
-		++mm->rss;
+		if (!PageReserved(new_page))
+			++mm->rss;
 		flush_icache_page(vma, new_page);
 		entry = mk_pte(new_page, vma->vm_page_prot);
 		if (write_access)