selftests/mm: allow tests to run with no huge pages support

Currently the mm selftests refuse to run if huge pages are not available
in the current system but this is an optional feature and not all the
tests actually require them.  Change the test during startup to be
non-fatal and skip or omit tests which actually rely on having huge pages,
allowing the other tests to be run.

The gup_test does support using madvise() to configure huge pages but it
ignores the error code so we just let it run.

Link: https://lkml.kernel.org/r/20250212-kselftest-mm-no-hugepages-v1-2-44702f538522@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nico Pache <npache@redhat.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 42 insertions, 24 deletions

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 7cc71d942f83b..93a606198751b 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -187,9 +187,10 @@ if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then
 		printf "Not enough huge pages available (%d < %d)\n" \
 		       "$freepgs" "$needpgs"
 	fi
+	HAVE_HUGEPAGES=1
 else
 	echo "no hugetlbfs support in kernel?"
-	exit 1
+	HAVE_HUGEPAGES=0
 fi
 
 # filter 64bit architectures
@@ -218,13 +219,20 @@ pretty_name() {
 # Usage: run_test [test binary] [arbitrary test arguments...]
 run_test() {
 	if test_selected ${CATEGORY}; then
+		local skip=0
+
 		# On memory constrainted systems some tests can fail to allocate hugepages.
 		# perform some cleanup before the test for a higher success rate.
 		if [ ${CATEGORY} == "thp" -o ${CATEGORY} == "hugetlb" ]; then
-			echo 3 > /proc/sys/vm/drop_caches
-			sleep 2
-			echo 1 > /proc/sys/vm/compact_memory
-			sleep 2
+			if [ "${HAVE_HUGEPAGES}" = "1" ]; then
+				echo 3 > /proc/sys/vm/drop_caches
+				sleep 2
+				echo 1 > /proc/sys/vm/compact_memory
+				sleep 2
+			else
+				echo "hugepages not supported" | tap_prefix
+				skip=1
+			fi
 		fi
 
 		local test=$(pretty_name "$*")
@@ -232,8 +240,12 @@ run_test() {
 		local sep=$(echo -n "$title" | tr "[:graph:][:space:]" -)
 		printf "%s\n%s\n%s\n" "$sep" "$title" "$sep" | tap_prefix
 
-		("$@" 2>&1) | tap_prefix
-		local ret=${PIPESTATUS[0]}
+		if [ "${skip}" != "1" ]; then
+			("$@" 2>&1) | tap_prefix
+			local ret=${PIPESTATUS[0]}
+		else
+			local ret=$ksft_skip
+		fi
 		count_total=$(( count_total + 1 ))
 		if [ $ret -eq 0 ]; then
 			count_pass=$(( count_pass + 1 ))
@@ -271,13 +283,15 @@ CATEGORY="hugetlb" run_test ./hugepage-vmemmap
 CATEGORY="hugetlb" run_test ./hugetlb-madvise
 CATEGORY="hugetlb" run_test ./hugetlb_dio
 
-nr_hugepages_tmp=$(cat /proc/sys/vm/nr_hugepages)
-# For this test, we need one and just one huge page
-echo 1 > /proc/sys/vm/nr_hugepages
-CATEGORY="hugetlb" run_test ./hugetlb_fault_after_madv
-CATEGORY="hugetlb" run_test ./hugetlb_madv_vs_map
-# Restore the previous number of huge pages, since further tests rely on it
-echo "$nr_hugepages_tmp" > /proc/sys/vm/nr_hugepages
+if [ "${HAVE_HUGEPAGES}" = "1" ]; then
+	nr_hugepages_tmp=$(cat /proc/sys/vm/nr_hugepages)
+	# For this test, we need one and just one huge page
+	echo 1 > /proc/sys/vm/nr_hugepages
+	CATEGORY="hugetlb" run_test ./hugetlb_fault_after_madv
+	CATEGORY="hugetlb" run_test ./hugetlb_madv_vs_map
+	# Restore the previous number of huge pages, since further tests rely on it
+	echo "$nr_hugepages_tmp" > /proc/sys/vm/nr_hugepages
+fi
 
 if test_selected "hugetlb"; then
 	echo "NOTE: These hugetlb tests provide minimal coverage.  Use"	  | tap_prefix
@@ -393,7 +407,9 @@ CATEGORY="memfd_secret" run_test ./memfd_secret
 fi
 
 # KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
-CATEGORY="ksm" run_test ./ksm_tests -H -s 100
+if [ "${HAVE_HUGEPAGES}" = "1" ]; then
+	CATEGORY="ksm" run_test ./ksm_tests -H -s 100
+fi
 # KSM KSM_MERGE_TIME test with size of 100
 CATEGORY="ksm" run_test ./ksm_tests -P -s 100
 # KSM MADV_MERGEABLE test with 10 identical pages
@@ -442,15 +458,17 @@ CATEGORY="thp" run_test ./transhuge-stress -d 20
 
 # Try to create XFS if not provided
 if [ -z "${SPLIT_HUGE_PAGE_TEST_XFS_PATH}" ]; then
-    if test_selected "thp"; then
-        if grep xfs /proc/filesystems &>/dev/null; then
-            XFS_IMG=$(mktemp /tmp/xfs_img_XXXXXX)
-            SPLIT_HUGE_PAGE_TEST_XFS_PATH=$(mktemp -d /tmp/xfs_dir_XXXXXX)
-            truncate -s 314572800 ${XFS_IMG}
-            mkfs.xfs -q ${XFS_IMG}
-            mount -o loop ${XFS_IMG} ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
-            MOUNTED_XFS=1
-        fi
+    if [ "${HAVE_HUGEPAGES}" = "1" ]; then
+	if test_selected "thp"; then
+	    if grep xfs /proc/filesystems &>/dev/null; then
+		XFS_IMG=$(mktemp /tmp/xfs_img_XXXXXX)
+		SPLIT_HUGE_PAGE_TEST_XFS_PATH=$(mktemp -d /tmp/xfs_dir_XXXXXX)
+		truncate -s 314572800 ${XFS_IMG}
+		mkfs.xfs -q ${XFS_IMG}
+		mount -o loop ${XFS_IMG} ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
+		MOUNTED_XFS=1
+	    fi
+	fi
     fi
 fi