Re: [PATCH v2 3/3] selftests/cgroup: Add test for preserving boot-isolated CPUs

[Waiman Long <longman@redhat.com>]

On 8/23/26 10:01 PM, Guopeng Zhang wrote:
> From: Guopeng Zhang <zhangguopeng@kylinos.cn>
>
> Put a CPU isolated at boot into an isolated partition, change the
> partition back to member and check that the CPU remains isolated.
>
> Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
> ---
>   .../selftests/cgroup/test_cpuset_prs.sh       | 58 +++++++++++++++++++
>   1 file changed, 58 insertions(+)
>
> diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> index fdb3185570d4..131d8b4551ef 100755
> --- a/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> +++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
> @@ -1155,6 +1155,63 @@ test_isolated()
>   	pause 0.05
>   }
>   
> +#
> +# Select an online CPU isolated from scheduler domains at boot.
> +# $1: test name used in the skip message
> +#
> +get_boot_isolated_cpu()
> +{
> +	TEST_NAME=$1
> +	BOOT_ISOLATED_FILE=/sys/devices/system/cpu/isolated
> +
> +	[[ -r $BOOT_ISOLATED_FILE ]] || {
> +		echo "$TEST_NAME test SKIPPED: boot isolation state unavailable"
> +		return 1
> +	}
> +	BOOT_CPUS=$(cat $BOOT_ISOLATED_FILE)
> +	[[ -n "$BOOT_CPUS" ]] || {
> +		echo "$TEST_NAME test SKIPPED: no boot-isolated CPU"
> +		return 1
> +	}
> +
> +	BOOT_CPU=$(echo "$BOOT_CPUS" | sed -e 's/[,-].*//')
> +	CPU_ONLINE=/sys/devices/system/cpu/cpu${BOOT_CPU}/online
> +	[[ ! -e $CPU_ONLINE || $(cat $CPU_ONLINE) -eq 1 ]] || {
> +		echo "$TEST_NAME test SKIPPED: CPU $BOOT_CPU is offline"
> +		return 1
> +	}
> +}
> +
> +#
> +# A CPU isolated at boot must stay isolated after it is released by a dynamic
> +# isolated partition.
> +#
> +test_boot_isolated()
> +{
> +	TEST_NAME="Boot-isolated CPU partition release"
> +	get_boot_isolated_cpu "$TEST_NAME" || return 0
> +	echo "Running $TEST_NAME test ..."
> +
> +	cd $CGROUP2/test
> +	echo member > cpuset.cpus.partition
> +	echo $BOOT_CPU > cpuset.cpus
> +	[[ $(cat cpuset.cpus.effective) = "$BOOT_CPU" ]] || {
> +		echo "$TEST_NAME test SKIPPED: CPU $BOOT_CPU is unavailable"
> +		echo "" > cpuset.cpus
> +		cd $CGROUP2
> +		return 0
> +	}
> +	test_partition isolated
> +	test_partition member
> +	check_isolcpus "." || {
> +		echo "Boot-isolated CPU $BOOT_CPU was lost after partition release"
> +		exit 1
> +	}
> +	echo "" > cpuset.cpus
> +	cd $CGROUP2
> +	echo "$TEST_NAME test PASSED."
> +}
> +
>   #
>   # Wait for inotify event for the given file and read it
>   # $1: cgroup file to wait for
> @@ -1226,5 +1283,6 @@ trap cleanup 0 2 3 6
>   run_state_test TEST_MATRIX
>   run_remote_state_test REMOTE_TEST_MATRIX
>   test_isolated
> +test_boot_isolated
>   test_inotify
>   echo "All tests PASSED."
Reviewed-by: Waiman Long <longman@redhat.com>