Add support for reserved keywords

Currently $pagesize, $mb_memory, and $ncpus are supported.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fio.c b/fio.c
index 7ad1b57..dfd15e0 100644
--- a/fio.c
+++ b/fio.c
@@ -1618,12 +1618,6 @@
 	if (!getenv("LC_NUMERIC"))
 		setlocale(LC_NUMERIC, "en_US");
 
-	if (parse_options(argc, argv))
-		return 1;
-
-	if (!thread_number)
-		return 0;
-
 	ps = sysconf(_SC_PAGESIZE);
 	if (ps < 0) {
 		log_err("Failed to get page size\n");
@@ -1633,6 +1627,14 @@
 	page_size = ps;
 	page_mask = ps - 1;
 
+	fio_keywords_init();
+
+	if (parse_options(argc, argv))
+		return 1;
+
+	if (!thread_number)
+		return 0;
+
 	if (write_bw_log) {
 		setup_log(&agg_io_log[DDIR_READ]);
 		setup_log(&agg_io_log[DDIR_WRITE]);