selftests/vm: run_vmtests.sh: update and clean up gup_test invocation

Run benchmarks on the _fast variants of gup and pup, as originally
intended.

Run the new gup_test sub-test: dump pages. In addition to exercising the
dump_page() call, it also demonstrates the various options you can use to
specify which pages to dump, and how.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: John Hubbard <[e-mail]>
Cc: Jérôme Glisse <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Ralph Campbell <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

tools/testing/selftests/vm/run_vmtests

···
 	echo "[PASS]"
 fi
 
-echo "--------------------------------------------"
-echo "running 'gup_test -U' (normal/slow gup)"
-echo "--------------------------------------------"
-./gup_test -U
+echo "------------------------------------------------------"
+echo "running: gup_test -u # get_user_pages_fast() benchmark"
+echo "------------------------------------------------------"
+./gup_test -u
 if [ $? -ne 0 ]; then
 	echo "[FAIL]"
 	exitcode=1
···
 	echo "[PASS]"
 fi
 
-echo "------------------------------------------"
-echo "running gup_test -b (pin_user_pages)"
-echo "------------------------------------------"
-./gup_test -b
+echo "------------------------------------------------------"
+echo "running: gup_test -a # pin_user_pages_fast() benchmark"
+echo "------------------------------------------------------"
+./gup_test -a
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+	exitcode=1
+else
+	echo "[PASS]"
+fi
+
+echo "------------------------------------------------------------"
+echo "# Dump pages 0, 19, and 4096, using pin_user_pages:"
+echo "running: gup_test -ct -F 0x1 0 19 0x1000 # dump_page() test"
+echo "------------------------------------------------------------"
+./gup_test -ct -F 0x1 0 19 0x1000
 if [ $? -ne 0 ]; then
 	echo "[FAIL]"
 	exitcode=1