[PATCH v2 1/3] selftests/cgroup: Drop invalid boot isolation comparison

[Guopeng Zhang <guopeng.zhang@linux.dev>]

From: Guopeng Zhang <zhangguopeng@kylinos.cn>

check_isolcpus() clears ISOLCPUS before rebuilding it from sched domain
data. Comparing that empty value with
/sys/devices/system/cpu/isolated makes the test fail whenever
isolcpus=domain is present.

That sysfs file is generated from HK_TYPE_DOMAIN_BOOT and does not change
when cpuset updates HK_TYPE_DOMAIN. Re-reading it cannot validate dynamic
housekeeping updates. The cpuset.cpus.isolated and sched domain checks
already cover the two dynamic interfaces, so remove the invalid comparison.

This can be reproduced on a kernel booted with isolcpus=domain,15:

    # tools/testing/selftests/cgroup/test_cpuset_prs.sh

The test fails its first state-matrix isolation check before the change and
continues past that check afterward.

Fixes: 6df415aa46ec ("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue")
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
---
 tools/testing/selftests/cgroup/test_cpuset_prs.sh | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
index da8f7b920178..fdb3185570d4 100755
--- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -797,7 +797,6 @@ check_isolcpus()
 	EXPECTED_ISOLCPUS=$1
 	ISCPUS=${CGROUP2}/cpuset.cpus.isolated
 	ISOLCPUS=$(cat $ISCPUS)
-	HKICPUS=$(cat /sys/devices/system/cpu/isolated)
 	LASTISOLCPU=
 	SCHED_DOMAINS=/sys/kernel/debug/sched/domains
 	if [[ $EXPECTED_ISOLCPUS = . ]]
@@ -835,11 +834,6 @@ check_isolcpus()
 	ISOLCPUS=
 	EXPECTED_ISOLCPUS=$EXPECTED_SDOMAIN
 
-	#
-	# The inverse of HK_TYPE_DOMAIN cpumask in $HKICPUS should match $ISOLCPUS
-	#
-	[[ "$ISOLCPUS" != "$HKICPUS" ]] && return 1
-
 	#
 	# Use the sched domain in debugfs to check isolated CPUs, if available
 	#
-- 
2.43.0