diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index be65843..f3ddbb0 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1528,8 +1528,9 @@
 		    "list of cpus to monitor"),
 	OPT_BOOLEAN(0, "no-inherit", &trace.opts.no_inherit,
 		    "child tasks do not inherit counters"),
-	OPT_UINTEGER('m', "mmap-pages", &trace.opts.mmap_pages,
-		     "number of mmap data pages"),
+	OPT_CALLBACK('m', "mmap-pages", &trace.opts.mmap_pages, "pages",
+		     "number of mmap data pages",
+		     perf_evlist__parse_mmap_pages),
 	OPT_STRING('u', "uid", &trace.opts.target.uid_str, "user",
 		   "user to profile"),
 	OPT_CALLBACK(0, "duration", &trace, "float",