From: Waiman Long <longman@redhat.com> To: Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>, Johannes Weiner <hannes@cmpxchg.org>, Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org> Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, "Andrew Morton" <akpm@linux-foundation.org>, "Roman Gushchin" <guro@fb.com>, "Phil Auld" <pauld@redhat.com>, "Peter Zijlstra" <peterz@infradead.org>, "Juri Lelli" <juri.lelli@redhat.com>, "Frederic Weisbecker" <frederic@kernel.org>, "Marcelo Tosatti" <mtosatti@redhat.com>, "Michal Koutný" <mkoutny@suse.com>, "Waiman Long" <longman@redhat.com> Subject: [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug Date: Tue, 20 Jul 2021 10:18:27 -0400 [thread overview] Message-ID: <20210720141834.10624-3-longman@redhat.com> (raw) In-Reply-To: <20210720141834.10624-1-longman@redhat.com> In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long <longman@redhat.com> --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index f5fef5516d99..b00982e6f6d8 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3166,6 +3166,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); + /* + * In the rare case that hotplug removes just all the cpus in + * subparts_cpus, we assumed that cpus are updated. + */ + if (!cpus_updated && top_cpuset.nr_subparts_cpus) + cpus_updated = true; + /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock); -- 2.18.1
WARNING: multiple messages have this Message-ID (diff)
From: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>, Shuah Khan <shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Andrew Morton" <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, "Roman Gushchin" <guro-b10kYP2dOMg@public.gmane.org>, "Phil Auld" <pauld-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "Peter Zijlstra" <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, "Juri Lelli" <juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "Frederic Weisbecker" <frederic-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, "Marcelo Tosatti" <mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "Michal Koutný" <mkoutny-IBi9RG/b67k@public.gmane.org>, "Waiman Long" <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Subject: [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug Date: Tue, 20 Jul 2021 10:18:27 -0400 [thread overview] Message-ID: <20210720141834.10624-3-longman@redhat.com> (raw) In-Reply-To: <20210720141834.10624-1-longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case. Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index f5fef5516d99..b00982e6f6d8 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3166,6 +3166,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems); + /* + * In the rare case that hotplug removes just all the cpus in + * subparts_cpus, we assumed that cpus are updated. + */ + if (!cpus_updated && top_cpuset.nr_subparts_cpus) + cpus_updated = true; + /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock); -- 2.18.1
next prev parent reply other threads:[~2021-07-20 14:33 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-20 14:18 [PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long 2021-07-20 14:18 ` [PATCH v3 1/9] cgroup/cpuset: Miscellaneous code cleanup Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-26 22:56 ` Tejun Heo 2021-07-26 22:56 ` Tejun Heo 2021-07-20 14:18 ` Waiman Long [this message] 2021-07-20 14:18 ` [PATCH v3 2/9] cgroup/cpuset: Fix a partition bug with hotplug Waiman Long 2021-07-26 22:59 ` Tejun Heo 2021-07-26 22:59 ` Tejun Heo 2021-07-27 20:16 ` Waiman Long 2021-07-20 14:18 ` [PATCH v3 3/9] cgroup/cpuset: Fix violation of cpuset locking rule Waiman Long 2021-07-26 23:10 ` Tejun Heo 2021-07-20 14:18 ` [PATCH v3 4/9] cgroup/cpuset: Enable event notification when partition become invalid Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-26 23:14 ` Tejun Heo 2021-07-27 20:26 ` Waiman Long 2021-07-27 20:26 ` Waiman Long 2021-07-27 20:46 ` Waiman Long 2021-07-27 20:46 ` Waiman Long 2021-07-20 14:18 ` [PATCH v3 5/9] cgroup/cpuset: Clarify the use of invalid partition root Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-20 14:18 ` [PATCH v3 6/9] cgroup/cpuset: Add a new isolated cpus.partition type Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-27 11:42 ` Frederic Weisbecker 2021-07-27 15:56 ` Waiman Long 2021-07-27 15:56 ` Waiman Long 2021-07-29 11:03 ` Frederic Weisbecker 2021-07-28 16:09 ` Michal Koutný 2021-07-28 16:27 ` Waiman Long 2021-07-28 17:25 ` Michal Koutný 2021-07-28 17:25 ` Michal Koutný 2021-07-20 14:18 ` [PATCH v3 7/9] cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-20 14:18 ` [PATCH v3 8/9] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-20 14:18 ` [PATCH v3 9/9] kselftest/cgroup: Add cpuset v2 partition root state test Waiman Long 2021-07-20 14:18 ` Waiman Long 2021-07-26 23:17 ` [PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Tejun Heo 2021-07-26 23:17 ` Tejun Heo 2021-07-27 21:14 ` Waiman Long 2021-08-09 22:46 ` Tejun Heo 2021-08-10 1:12 ` Waiman Long 2021-08-10 1:12 ` Waiman Long
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