xpmem: support large page

1. try to use as large page as possible on attach
2. pre-map resident remote pages on attach

Change-Id: I5580682a4199e94085a9bad9ce3958a0f14cdcea

test/issues/1259/mc_run.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+test -e /tmp/xpmem.share && rm -f /tmp/xpmem.share
+test -e /tmp/xpmem.lock && rm -f /tmp/xpmem.lock
+
+# create TMP_SHARE_SIZE bytes defined in xpmem_test.h
+for i in `seq 0 31` ; do
+	echo -n 0 >> /tmp/xpmem.share
+done
+echo 0 > /tmp/xpmem.lock
+
+# Run the main test app
+${MCEXEC} $PWD/xpmem_master
+exit 0
+