[PATCH-next v2 6/6] selftests/cgroup: Skip test_cpuset_prs.sh test if some required CPUs are offline

[Waiman Long]

The test_cpuset_prs.sh test assumes that all the relevant CPUs being
tested are online. If some of them are offline, some of the test cases
may fail. So skip the test if the required CPUs are either offline or
not present.

Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
 .../selftests/cgroup/test_cpuset_prs.sh       | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index 3d392e8c66aa..f57971ebb90e 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -118,6 +118,26 @@ TEST_ISOLCPUS=
 		skip_test "Current isolated CPUs ($CURRENT_ISOLCPUS) don't match boot isolated CPUs!"
 }
 
+#
+# This test assumes that all the relevant CPUs being tested are online.
+# If some of them are offline, some of the tests may fail. So we are going to
+# skip running this test script if some of the required CPUs may be offline.
+# The required CPUs include CPUs 0-7 and the first boot time isolated CPU if
+# present. However the check below is not exhaustive and can be a false
+# positive, but users should not run this test if some CPUs are offline.
+#
+ONLINE_CPUS=$(cat /sys/devices/system/cpu/online | sed -e "s/,.*//")
+ONLINE_FIRST=$(echo $ONLINE_CPUS | sed -e "s/-.*//")
+ONLINE_LAST=$(echo $ONLINE_CPUS | sed -e "s/.*-//")
+if [[ -n "$FIRST_ISOLCPUS" ]]
+then
+	LAST_REQUIRED_CPU=$FIRST_ISOLCPUS
+else
+	LAST_REQUIRED_CPU=7
+fi
+[[ $ONLINE_FIRST != 0 || $ONLINE_LAST -lt $LAST_REQUIRED_CPU ]] &&
+	skip_test "Some of the required CPUs are offline or not present!"
+
 cleanup()
 {
 	online_cpus
-- 
2.55.0