mm/debug: print hashed address of struct page

The actual address of the struct page isn't particularly helpful, while
the hashed address helps match with other messages elsewhere.  Add the PFN
that the page refers to in order to help diagnose problems where the page
is improperly aligned for the purpose.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Link: http://lkml.kernel.org/r/20200709202117.7216-7-willy@infradead.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/debug.c

@@ -95,17 +95,17 @@ void __dump_page(struct page *page, const char *reason)
 	 */
 	mapcount = PageSlab(head) ? 0 : page_mapcount(page);
 
-	pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
+	pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
 			page, page_ref_count(head), mapcount, mapping,
-			page_to_pgoff(page));
+			page_to_pgoff(page), page_to_pfn(page));
 	if (compound) {
 		if (hpage_pincount_available(page)) {
-			pr_warn("head:%px order:%u compound_mapcount:%d compound_pincount:%d\n",
+			pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
 					head, compound_order(head),
 					compound_mapcount(head),
 					compound_pincount(head));
 		} else {
-			pr_warn("head:%px order:%u compound_mapcount:%d\n",
+			pr_warn("head:%p order:%u compound_mapcount:%d\n",
 					head, compound_order(head),
 					compound_mapcount(head));
 		}