[PATCH 0/2] selftests/mm: Allow execution on systems without huge pages

[PATCH 0/2] selftests/mm: Allow execution on systems without huge pages

[Mark Brown]

Currently the mm selftests refuse to run if we don't have huge page
support but there are plenty of tests that don't depend on this feature,
relax this requirement to allow coverage on relevant systems (eg, most
32 bit arm ones).

While doing this I noticed a bug with an existing check if we're running
THP tests, the fix overlaps with the above change so is sent as part of
a series.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
Mark Brown (2):
      selftests/mm: Fix check for running THP tests
      selftests/mm: Allow tests to run with no huge pages support

 tools/testing/selftests/mm/run_vmtests.sh | 68 +++++++++++++++++++------------
 1 file changed, 43 insertions(+), 25 deletions(-)
---
base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3
change-id: 20250211-kselftest-mm-no-hugepages-ee5917a170eb

Best regards,
-- 
Mark Brown <broonie@kernel.org>

[PATCH 1/2] selftests/mm: Fix check for running THP tests

[Mark Brown]

When testing if we should try to compact memory or drop caches before we
run the THP or HugeTLB tests we use | as an or operator. This doesn't work
since run_vmtests.sh is written in shell where this is used to pipe the
output of the first argument into the second. Instead use the shell's -o
operator.

Fixes: b433ffa8dbac ("selftests: mm: perform some system cleanup before using hugepages")
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/mm/run_vmtests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 333c468c26991421cd8f9ce6d995f9b64b0643c7..da7e266681031d2772fb0c4139648904a18e0bf9 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -220,7 +220,7 @@ run_test() {
 	if test_selected ${CATEGORY}; then
 		# 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" ] | [ ${CATEGORY} == "hugetlb" ]; then
+		if [ ${CATEGORY} == "thp" -o ${CATEGORY} == "hugetlb" ]; then
 			echo 3 > /proc/sys/vm/drop_caches
 			sleep 2
 			echo 1 > /proc/sys/vm/compact_memory

-- 
2.39.5

[PATCH 2/2] selftests/mm: Allow tests to run with no huge pages support

[Mark Brown]

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.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/mm/run_vmtests.sh | 66 ++++++++++++++++++++-----------
 1 file changed, 42 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index da7e266681031d2772fb0c4139648904a18e0bf9..d3866b50a6e16a9ba08b6cf33d131edf2a9226be 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
@@ -391,7 +405,9 @@ 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
@@ -440,15 +456,17 @@ 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
 

-- 
2.39.5

Re: [PATCH 1/2] selftests/mm: Fix check for running THP tests

[Nico Pache]

On Wed, Feb 12, 2025 at 10:52 AM Mark Brown <broonie@kernel.org> wrote:
>
> When testing if we should try to compact memory or drop caches before we
> run the THP or HugeTLB tests we use | as an or operator. This doesn't work
> since run_vmtests.sh is written in shell where this is used to pipe the
> output of the first argument into the second. Instead use the shell's -o
> operator.
>
> Fixes: b433ffa8dbac ("selftests: mm: perform some system cleanup before using hugepages")
> Signed-off-by: Mark Brown <broonie@kernel.org>

Ah I meant to use || which i believe also works in shell. Thanks for the fix!

Reviewed-by: Nico Pache <npache@redhat.com>
> ---
>  tools/testing/selftests/mm/run_vmtests.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index 333c468c26991421cd8f9ce6d995f9b64b0643c7..da7e266681031d2772fb0c4139648904a18e0bf9 100755
> --- a/tools/testing/selftests/mm/run_vmtests.sh
> +++ b/tools/testing/selftests/mm/run_vmtests.sh
> @@ -220,7 +220,7 @@ run_test() {
>         if test_selected ${CATEGORY}; then
>                 # 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" ] | [ ${CATEGORY} == "hugetlb" ]; then
> +               if [ ${CATEGORY} == "thp" -o ${CATEGORY} == "hugetlb" ]; then
>                         echo 3 > /proc/sys/vm/drop_caches
>                         sleep 2
>                         echo 1 > /proc/sys/vm/compact_memory
>
> --
> 2.39.5
>

Re: [PATCH 2/2] selftests/mm: Allow tests to run with no huge pages support

[Nico Pache]

On Wed, Feb 12, 2025 at 10:52 AM Mark Brown <broonie@kernel.org> wrote:
>
> 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.
>
> Signed-off-by: Mark Brown <broonie@kernel.org>

We currently deal with the same issue when running selftests on
smaller machines or 64k kernels. This is a nice addition.

Reviewed-by: Nico Pache <npache@redhat.com>

> ---
>  tools/testing/selftests/mm/run_vmtests.sh | 66 ++++++++++++++++++++-----------
>  1 file changed, 42 insertions(+), 24 deletions(-)
>
> diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
> index da7e266681031d2772fb0c4139648904a18e0bf9..d3866b50a6e16a9ba08b6cf33d131edf2a9226be 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 "$nr_hugepages_tmp" > /proc/sys/vm/nr_hugepages
> +fi
>
>  if test_selected "hugetlb"; then
>         echo "NOTE: These hugetlb tests provide minimal coverage.  Use"   | tap_prefix
> @@ -391,7 +405,9 @@ CATEGORY="memfd_secret" run_test ./memfd_secret
>  fi
>
>  # KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100
> -CATEGORY="ksm" run_test ./ksm_tests -H -s 100
> +if [ "${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
> @@ -440,15 +456,17 @@ 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
>
>
> --
> 2.39.5
>