There was a memory leak bug in DAMOS sysfs memcg_path file. Add a selftest to ensure the bug never comes back.

Signed-off-by: SeongJae Park sj@kernel.org --- tools/testing/selftests/damon/Makefile | 1 + .../selftests/damon/sysfs_memcg_path_leak.sh | 43 +++++++++++++++++++ 2 files changed, 44 insertions(+) create mode 100755 tools/testing/selftests/damon/sysfs_memcg_path_leak.sh

diff --git a/tools/testing/selftests/damon/Makefile b/tools/testing/selftests/damon/Makefile index ff21524be458..e888455e3cf8 100644 --- a/tools/testing/selftests/damon/Makefile +++ b/tools/testing/selftests/damon/Makefile @@ -15,6 +15,7 @@ TEST_PROGS += reclaim.sh lru_sort.sh # regression tests (reproducers of previously found bugs) TEST_PROGS += sysfs_update_removed_scheme_dir.sh TEST_PROGS += sysfs_update_schemes_tried_regions_hang.py +TEST_PROGS += sysfs_memcg_path_leak.sh

EXTRA_CLEAN = __pycache__

diff --git a/tools/testing/selftests/damon/sysfs_memcg_path_leak.sh b/tools/testing/selftests/damon/sysfs_memcg_path_leak.sh new file mode 100755 index 000000000000..64c5d8c518a4 --- /dev/null +++ b/tools/testing/selftests/damon/sysfs_memcg_path_leak.sh @@ -0,0 +1,43 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +if [ $EUID -ne 0 ] +then + echo "Run as root" + exit $ksft_skip +fi + +damon_sysfs="/sys/kernel/mm/damon/admin" +if [ ! -d "$damon_sysfs" ] +then + echo "damon sysfs not found" + exit $ksft_skip +fi + +# ensure filter directory +echo 1 > "$damon_sysfs/kdamonds/nr_kdamonds" +echo 1 > "$damon_sysfs/kdamonds/0/contexts/nr_contexts" +echo 1 > "$damon_sysfs/kdamonds/0/contexts/0/schemes/nr_schemes" +echo 1 > "$damon_sysfs/kdamonds/0/contexts/0/schemes/0/filters/nr_filters" + +filter_dir="$damon_sysfs/kdamonds/0/contexts/0/schemes/0/filters/0" + +before_kb=$(grep Slab /proc/meminfo | awk '{print $2}') + +# try to leak 3000 KiB +for i in {1..102400}; +do + echo "012345678901234567890123456789" > "$filter_dir/memcg_path" +done + +after_kb=$(grep Slab /proc/meminfo | awk '{print $2}') +# expect up to 1500 KiB free from other tasks memory +expected_after_kb_max=$((before_kb + 1500)) + +if [ "$after_kb" -gt "$expected_after_kb_max" ] +then + echo "maybe memcg_path are leaking: $before_kb -> $after_kb" + exit 1 +else + exit 0 +fi