From nobody Mon Sep 28 09:57:58 2026 Received: from mta1.migadu.com (out-12.mta1.migadu.com [95.215.58.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05008231832 for ; Mon, 24 Aug 2026 02:02:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.12 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536925; cv=none; b=C6hO2bNtt6g60fhRnRKxUbzwVCcoLnTlNJIa8kEZaiejrBT9fb0SYKOxR1t0di/twbuOecFjunnMxHi/ctRHon6gKUyfnHxYSaOkCCyzQCdB96tSnKmRfoLiDZO4GlC6ceiY3Qjm/66KZ9gRMUsBnYgudCDCRqG9lSJOcuqOmo8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536925; c=relaxed/simple; bh=oPU623iWilh9XaksB9VuYgRSYCtbcJaJP8c1AFVWnYY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hkpKyGdAaky21rSy7BY3w7mRSr4Bz0mgIsTzXCMES6MC1iSOtYfZyuUdZwVmgysQnCrF/3AAjYra8Ha2kgKbUYFfwwK23GN/CpBcyh+W13k7g/GFJiF34FdAAGEt4hcXqloYGs421Po/r6nkgYp7zj3smUM/ayB7XEs36lxAfWE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=m3WGmHuu; arc=none smtp.client-ip=95.215.58.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="m3WGmHuu" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=oPU623iWilh9XaksB9VuYgRSYCtbcJaJP8c1AFVWnYY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787536921; v=1; x=1788141721; b=m3WGmHuuFsqCKGrefPnLWg0hXhNte/Er7JNc9GhSux3ijWoDr8xitSu75HHfaqLbIlW9i+UP 4knGG2HBvVNyhAERSjeT/HViZV95U3tkNzk5ENp27HvcX7FzMboH5qQZPJT8hQjAt2fQl/Hc+Bt po85d0COwaWTPTbjFZsXzDgE= X-Envelope-To: linux-kernel@vger.kernel.org Received: from zgp.. (223.70.159.239) by smtp.migadu.com with ESMTPS id 5ca004a53aa70452; Mon, 24 Aug 2026 02:02:00 +0000 X-Mizu-Trace-ID: 5ca004a53aa70452 X-Migadu-Flow: FLOW_OUT From: Guopeng Zhang To: Waiman Long , Tejun Heo , Ridong Chen Cc: Johannes Weiner , Michal Koutny , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Guopeng Zhang Subject: [PATCH v2 1/3] selftests/cgroup: Drop invalid boot isolation comparison Date: Mon, 24 Aug 2026 10:01:38 +0800 Message-ID: <20260824020140.21130-2-guopeng.zhang@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260824020140.21130-1-guopeng.zhang@linux.dev> References: <20260824020140.21130-1-guopeng.zhang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Guopeng Zhang 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=3Ddomain 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=3Ddomain,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 Reviewed-by: Waiman Long --- 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/test= ing/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=3D$1 ISCPUS=3D${CGROUP2}/cpuset.cpus.isolated ISOLCPUS=3D$(cat $ISCPUS) - HKICPUS=3D$(cat /sys/devices/system/cpu/isolated) LASTISOLCPU=3D SCHED_DOMAINS=3D/sys/kernel/debug/sched/domains if [[ $EXPECTED_ISOLCPUS =3D . ]] @@ -835,11 +834,6 @@ check_isolcpus() ISOLCPUS=3D EXPECTED_ISOLCPUS=3D$EXPECTED_SDOMAIN =20 - # - # The inverse of HK_TYPE_DOMAIN cpumask in $HKICPUS should match $ISOLCPUS - # - [[ "$ISOLCPUS" !=3D "$HKICPUS" ]] && return 1 - # # Use the sched domain in debugfs to check isolated CPUs, if available # --=20 2.43.0 From nobody Mon Sep 28 09:57:58 2026 Received: from mta0.migadu.com (out-76.mta0.migadu.com [91.218.175.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF300231832 for ; Mon, 24 Aug 2026 02:02:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.76 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536931; cv=none; b=bLXTZsSrY2eQbB+4QMeXofO2BdKfoWzz6SEOpPUss+MjBhjSNMh8AVVFFiIgm+cnCKI502uHFDCI2qovd+iqDXCQ4OoknmkbTu/dEqF1TYN5Sn3/kd8jdH5rFynqCqpKKCHxOsQBNbVQqsrTLKa3I94F7UBoTgtmLJANiBH8FB4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536931; c=relaxed/simple; bh=zhkDTRg3fU16t0nSAOmBqRUjwq8Q7ubl21hlDlnXRhU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=A06nDVZ483rEO2lR3xQqL+0r+fjj1LAh4VmVzARKuVf5l/xX4Dr0VTPlores8hjknPb4w5+TuT8uhS/je7dLoecbDf9jzq1n9A2FY4s/C/4Hr27mUkWHCD+ACjMPsyrmgzZ2AF8eMJUUte2wlV+puX1LrozNE1bK2CVNtbmohb0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=wy9gk+6Z; arc=none smtp.client-ip=91.218.175.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="wy9gk+6Z" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=zhkDTRg3fU16t0nSAOmBqRUjwq8Q7ubl21hlDlnXRhU=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787536926; v=1; x=1788141726; b=wy9gk+6ZHCcfVIMQnIji/a3hDz83MdJIldwUsIqrn9qQyD2oTH2AWnwKJ8o6Ai+rRu/F8OWU DxWCuhgMxCUUQWA7kZR3CXg8rOlW8el7rT3jUsXfCIY7CM3gmmHH2j7JOK8EFeE55wpQqD1BLup dVrlyyonKsTXo+kJqamneB2M= X-Envelope-To: linux-kernel@vger.kernel.org Received: from zgp.. (223.70.159.239) by smtp.migadu.com with ESMTPS id e17b4879cbf4d495; Mon, 24 Aug 2026 02:02:06 +0000 X-Mizu-Trace-ID: e17b4879cbf4d495 X-Migadu-Flow: FLOW_OUT From: Guopeng Zhang To: Waiman Long , Tejun Heo , Ridong Chen Cc: Johannes Weiner , Michal Koutny , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Guopeng Zhang Subject: [PATCH v2 2/3] cgroup/cpuset: Preserve boot-isolated CPUs on partition release Date: Mon, 24 Aug 2026 10:01:39 +0800 Message-ID: <20260824020140.21130-3-guopeng.zhang@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260824020140.21130-1-guopeng.zhang@linux.dev> References: <20260824020140.21130-1-guopeng.zhang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Guopeng Zhang isolated_cpus tracks CPUs isolated with isolcpus=3D as well as CPUs in isolated cpuset partitions. When an isolated partition is released, isolated_cpus_update() removes its whole CPU mask. This also clears CPUs which were already isolated at boot. This can be reproduced on a cgroup v2 system booted with isolcpus=3Ddomain,15: cd /sys/fs/cgroup echo +cpuset > cgroup.subtree_control mkdir cpuset-repro echo 15 > cpuset-repro/cpuset.cpus echo isolated > cpuset-repro/cpuset.cpus.partition echo member > cpuset-repro/cpuset.cpus.partition cat cpuset.cpus.isolated CPU 15 is absent before the change. It must remain in cpuset.cpus.isolated after the partition is released. Update isolated_cpus one CPU at a time and keep CPUs outside the boot-time domain housekeeping mask isolated. Fixes: c188f33c864e ("cgroup/cpuset: Account for boot time isolated CPUs") Signed-off-by: Guopeng Zhang Acked-by: Waiman Long --- kernel/cgroup/cpuset.c | 39 +++++++++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 10 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index d100634fa12b..2538faac9aba 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1259,6 +1259,28 @@ static void reset_partition_data(struct cpuset *cs) cpumask_copy(cs->effective_cpus, parent->effective_cpus); } =20 +/* Return true if isolated_cpus changes. */ +static bool isolated_cpu_update(int new_prs, int cpu) +{ + lockdep_assert_held(&callback_lock); + lockdep_assert_held(&cpuset_mutex); + + if (new_prs =3D=3D PRS_ISOLATED) { + if (cpumask_test_cpu(cpu, isolated_cpus)) + return false; + cpumask_set_cpu(cpu, isolated_cpus); + return true; + } + + /* CPUs isolated at boot must remain isolated. */ + if (!cpumask_test_cpu(cpu, + housekeeping_cpumask(HK_TYPE_DOMAIN_BOOT)) || + !cpumask_test_cpu(cpu, isolated_cpus)) + return false; + cpumask_clear_cpu(cpu, isolated_cpus); + return true; +} + /* * isolated_cpus_update - Update the isolated_cpus mask * @old_prs: old partition_root_state @@ -1267,19 +1289,16 @@ static void reset_partition_data(struct cpuset *cs) */ static void isolated_cpus_update(int old_prs, int new_prs, struct cpumask = *xcpus) { + bool updated =3D false; + int cpu; + WARN_ON_ONCE(old_prs =3D=3D new_prs); lockdep_assert_held(&callback_lock); lockdep_assert_held(&cpuset_mutex); - if (new_prs =3D=3D PRS_ISOLATED) { - if (cpumask_subset(xcpus, isolated_cpus)) - return; - cpumask_or(isolated_cpus, isolated_cpus, xcpus); - } else { - if (!cpumask_intersects(xcpus, isolated_cpus)) - return; - cpumask_andnot(isolated_cpus, isolated_cpus, xcpus); - } - update_housekeeping =3D true; + for_each_cpu(cpu, xcpus) + updated |=3D isolated_cpu_update(new_prs, cpu); + if (updated) + update_housekeeping =3D true; } =20 /* --=20 2.43.0 From nobody Mon Sep 28 09:57:58 2026 Received: from mta1.migadu.com (out-17.mta1.migadu.com [95.215.58.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9215A30F7E8 for ; Mon, 24 Aug 2026 02:02:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536939; cv=none; b=l7WgQ0zSypg5YIMid1w/R+A4xTsB6waKmfIhyPFgYuj5vWPg3v+IBa9u+Ub4cpSRvtKXUrAkUIS2SSnfCsnjdF7nWE9oGM6XSWxZom5ehaBTAfEDduT2hysnzPQW7s6Wq3aOoxCWRnNNHqhcVzHEGJcKldynjrrB5XqjSRyBunU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787536939; c=relaxed/simple; bh=xzuiCyOQkUshOw/dQoqpJd4cRH9nvcLkQjfLEBLwDso=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=vAUOH8nRoNdfo8kzniAuvy8clNzfnPwr9PYuFCJLFjvYrnvgqFZ8QpFqtbiwvbz1Y+A21lD9kxlzOTAmOnK1dLJTuKdsp9wAOJROa4GdakNtDbC5g+afget7pkPViiKOZS4OHxk2KBSndEWqiTooBMJ4LvE4AfTbNSRpH/DQ+JU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ePUAeIbT; arc=none smtp.client-ip=95.215.58.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ePUAeIbT" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=xzuiCyOQkUshOw/dQoqpJd4cRH9nvcLkQjfLEBLwDso=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787536935; v=1; x=1788141735; b=ePUAeIbTsQ3Rv6zSNS/shGcqqDvT0PGk0+NwtpsC6xA/eciFnPFeVnvM+2Yc7uay5Ijn0Xoo dPzzR2mBYOFXYefTVixXiRpTCPF7mbwhvWOgjQxctm3f2wuSzSXbPD/TeMP7T5CUKj5XdFgtIs6 jC+HqdrZqNez2yVAbu0j0HMI= X-Envelope-To: linux-kernel@vger.kernel.org Received: from zgp.. (223.70.159.239) by smtp.migadu.com with ESMTPS id 0c116af405542692; Mon, 24 Aug 2026 02:02:15 +0000 X-Mizu-Trace-ID: 0c116af405542692 X-Migadu-Flow: FLOW_OUT From: Guopeng Zhang To: Waiman Long , Tejun Heo , Ridong Chen Cc: Johannes Weiner , Michal Koutny , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Guopeng Zhang Subject: [PATCH v2 3/3] selftests/cgroup: Add test for preserving boot-isolated CPUs Date: Mon, 24 Aug 2026 10:01:40 +0800 Message-ID: <20260824020140.21130-4-guopeng.zhang@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260824020140.21130-1-guopeng.zhang@linux.dev> References: <20260824020140.21130-1-guopeng.zhang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Guopeng Zhang 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 Reviewed-by: Waiman Long --- .../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/test= ing/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 } =20 +# +# Select an online CPU isolated from scheduler domains at boot. +# $1: test name used in the skip message +# +get_boot_isolated_cpu() +{ + TEST_NAME=3D$1 + BOOT_ISOLATED_FILE=3D/sys/devices/system/cpu/isolated + + [[ -r $BOOT_ISOLATED_FILE ]] || { + echo "$TEST_NAME test SKIPPED: boot isolation state unavailable" + return 1 + } + BOOT_CPUS=3D$(cat $BOOT_ISOLATED_FILE) + [[ -n "$BOOT_CPUS" ]] || { + echo "$TEST_NAME test SKIPPED: no boot-isolated CPU" + return 1 + } + + BOOT_CPU=3D$(echo "$BOOT_CPUS" | sed -e 's/[,-].*//') + CPU_ONLINE=3D/sys/devices/system/cpu/cpu${BOOT_CPU}/online + [[ ! -e $CPU_ONLINE || $(cat $CPU_ONLINE) -eq 1 ]] || { + echo "$TEST_NAME test SKIPPED: CPU $BOOT_CPU is offline" + return 1 + } +} + +# +# A CPU isolated at boot must stay isolated after it is released by a dyna= mic +# isolated partition. +# +test_boot_isolated() +{ + TEST_NAME=3D"Boot-isolated CPU partition release" + get_boot_isolated_cpu "$TEST_NAME" || return 0 + echo "Running $TEST_NAME test ..." + + cd $CGROUP2/test + echo member > cpuset.cpus.partition + echo $BOOT_CPU > cpuset.cpus + [[ $(cat cpuset.cpus.effective) =3D "$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." --=20 2.43.0