[PATCH v2 6/7] selftests/mm: Skip thuge-gen if shmmax is too small or no 1G huge pages

[Aboorva Devarajan <aboorvad@linux.ibm.com>]

Make thuge-gen skip instead of fail when it can't run due to system
settings. If shmmax is too small or no 1G huge pages are available,
the test now prints a warning and is marked as skipped.

-------------------
Before Patch:
-------------------
~ running ./thuge-gen
~ Bail out! Please do echo 262144 > /proc/sys/kernel/shmmax
~ Totals: pass:0 fail:0 xfail:0 xpass:0 skip:0 error:0
~ [FAIL]
not ok 28 thuge-gen ~ exit=1

-------------------
After Patch:
-------------------
~ running ./thuge-gen
~ ~ WARNING: shmmax is too small to run this test.
~ ~ Please run the following command to increase shmmax:
~ ~ echo 262144 > /proc/sys/kernel/shmmax
~ 1..0 ~ SKIP Test skipped due to insufficient shmmax value.
~ [SKIP]
ok 29 thuge-gen ~ SKIP

Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
---
 tools/testing/selftests/mm/thuge-gen.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/thuge-gen.c b/tools/testing/selftests/mm/thuge-gen.c
index 8e2b08dc5762..4f5e290ff1a6 100644
--- a/tools/testing/selftests/mm/thuge-gen.c
+++ b/tools/testing/selftests/mm/thuge-gen.c
@@ -177,13 +177,16 @@ void find_pagesizes(void)
 	globfree(&g);
 
 	read_sysfs("/proc/sys/kernel/shmmax", &shmmax_val);
-	if (shmmax_val < NUM_PAGES * largest)
-		ksft_exit_fail_msg("Please do echo %lu > /proc/sys/kernel/shmmax",
-				   largest * NUM_PAGES);
+	if (shmmax_val < NUM_PAGES * largest) {
+		ksft_print_msg("WARNING: shmmax is too small to run this test.\n");
+		ksft_print_msg("Please run the following command to increase shmmax:\n");
+		ksft_print_msg("echo %lu > /proc/sys/kernel/shmmax\n", largest * NUM_PAGES);
+		ksft_exit_skip("Test skipped due to insufficient shmmax value.\n");
+	}
 
 #if defined(__x86_64__)
 	if (largest != 1U<<30) {
-		ksft_exit_fail_msg("No GB pages available on x86-64\n"
+		ksft_exit_skip("No GB pages available on x86-64\n"
 				   "Please boot with hugepagesz=1G hugepages=%d\n", NUM_PAGES);
 	}
 #endif
-- 
2.43.5