[PATCH-next v3 8/9] selftests/cgroup: Add tests for nohz_full housekeeping check

[Waiman Long]

When a boot time nohz_full CPUs are present and they cover CPUs 0-7,
some of the test cases may fail.  So the test run will be skipped with
a warning message in this case. On the other hand, if the boot time
nohz_full CPUs cover all the CPUs except 0-7, a special set of nohz_full
specific housekeeping check related tests could be run to make sure the
housekeeping check are behaving properly. The test_cpuset_prs.sh test
script is now updated to do exactly that.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
 .../selftests/cgroup/test_cpuset_prs.sh       | 34 +++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 5aac0df86593..ea0ebbdf4bb3 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -84,6 +84,29 @@ echo member > test/cpuset.cpus.partition
 echo "" > test/cpuset.cpus
 [[ $RESULT -eq 0 ]] && skip_test "Child cgroups are using cpuset!"
 
+#
+# If nohz_full CPUs have been reserved at boot time, they should not include
+# CPUs 0-7 as that may fail some of the test cases. On the other hand if the
+# set of nohz_full CPUs includes all the CPUs except 0-7, we can run a special
+# set of housekeeping CPUs exhaustion tests to see if the cpuset code will
+# reject them.
+#
+NOHZ_FULL_CPUS=$(cat /sys/devices/system/cpu/nohz_full)
+FIRST_NOHZ_FULL_CPU=
+LAST_NOHZ_FULL_CPU=
+RUN_NOHZ_FULL_TESTS=
+LAST_PRESENT_CPU=$(cat /sys/devices/system/cpu/present | sed -e "s/.*[,-]//")
+[[ -n "$NOHZ_FULL_CPUS" ]] && {
+	FIRST_NOHZ_FULL_CPU=$(echo $NOHZ_FULL_CPUS | sed -e "s/[,-].*//")
+	LAST_NOHZ_FULL_CPU=$(echo $NOHZ_FULL_CPUS | sed -e "s/.*[,-]//")
+	echo "Boot nohz_full CPUs: $NOHZ_FULL_CPUS"
+}
+[[ -n "$FIRST_NOHZ_FULL_CPU" && "$FIRST_NOHZ_FULL_CPU" -le 7 ]] &&
+	skip_test "Boot NOHZ_FULL CPUs overlap CPUs to be tested!"
+
+[[ -n "$FIRST_NOHZ_FULL_CPU" && "$FIRST_NOHZ_FULL_CPU" = 8 &&
+   "$LAST_NOHZ_FULL_CPU" = $LAST_PRESENT_CPU ]] && RUN_NOHZ_FULL_TESTS=1
+
 #
 # If isolated CPUs have been reserved at boot time (as shown in
 # /sys/devices/system/cpu/isolated), these isolated CPUs should be outside of
@@ -497,6 +520,16 @@ ISOLCPUS_TEST_MATRIX=(
 	" CX1-2,I:X1,I:P1 . .      .     X1,2,I  .      .      .     0 A1:1-2,I|XA1:1-2,I A1:P-1 ."
 )
 
+# Test matrix to be run when boot time nohz_full CPUs cover all CPUs except CPUs 0-7
+NOHZ_FULL_TEST_MATRIX=(
+	#  old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate ISOLCPUS
+	#  ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------ --------
+	# Using all the nohz_full HK CPUs 0-7 in isolated partition is not allowed
+	" C0-7       .      .      .      P2     .      .      .     0 A1:0-7 A1:P-2 ."
+	" C1-7:P2 C5-7:P2   .      .       .     .      .    C0:P2   0 A1:1-4|A2:5-7|B1:0
+								       A1:P2|A2:P2|B1:P-2 1-7"
+)
+
 #
 # Cpuset controller remote partition test matrix.
 #
@@ -1362,6 +1395,7 @@ trap cleanup 0 2 3 6
 run_state_test TEST_MATRIX
 run_remote_state_test REMOTE_TEST_MATRIX
 TEST_ISOLCPUS=1 run_state_test ISOLCPUS_TEST_MATRIX
+[[ -n "$RUN_NOHZ_FULL_TESTS" ]] && run_state_test NOHZ_FULL_TEST_MATRIX
 test_isolated
 test_boot_isolated
 test_inotify
-- 
2.55.0