From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: [PATCH 2/5] cgroup/cpuset: Include offline CPUs when tasks' cpumasks in top_cpuset are updated Date: Mon, 6 Mar 2023 15:08:46 -0500 Message-ID: <20230306200849.376804-3-longman@redhat.com> References: <20230306200849.376804-1-longman@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678133370; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XMpGzFxDVrhKLpAq2mb4oo3DA00+S6OlDRBjGlenDeM=; b=P0Py6VEag06c8j/FtieA8fOuQ4IryLTGa0zjr61JFxCE0ZhHHSIozCYmlz1kHuO5zup+mx uw0bmEsw2UDeDrTVEuJi6aauzWcyCrGl8QcSHYd9SviDVK6eAeESY6s6BJysUNjkVA1kJy jSgNpFTFsblDnIPxE+WVyrgd/osIyzY= In-Reply-To: <20230306200849.376804-1-longman@redhat.com> List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Will Deacon , Peter Zijlstra , Waiman Long Similar to commit 3fb906e7fabb ("group/cpuset: Don't filter offline CPUs in cpuset_cpus_allowed() for top cpuset tasks"), the whole set of possible CPUs including offline ones should be used for setting cpumasks for tasks in the top cpuset when a cpuset partition is modified. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index a801abad3bac..bbf57dcb2f68 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1209,7 +1209,8 @@ void rebuild_sched_domains(void) * * Iterate through each task of @cs updating its cpus_allowed to the * effective cpuset's. As this function is called with cpuset_rwsem held, - * cpuset membership stays stable. + * cpuset membership stays stable. For top_cpuset, task_cpu_possible_mask() + * is used instead of effective_cpus. */ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) { @@ -1219,15 +1220,18 @@ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) { - /* - * Percpu kthreads in top_cpuset are ignored - */ - if (top_cs && (task->flags & PF_KTHREAD) && - kthread_is_per_cpu(task)) - continue; + const struct cpumask *possible_mask = task_cpu_possible_mask(task); - cpumask_and(new_cpus, cs->effective_cpus, - task_cpu_possible_mask(task)); + if (top_cs) { + /* + * Percpu kthreads in top_cpuset are ignored + */ + if ((task->flags & PF_KTHREAD) && kthread_is_per_cpu(task)) + continue; + cpumask_andnot(new_cpus, possible_mask, cs->subparts_cpus); + } else { + cpumask_and(new_cpus, cs->effective_cpus, possible_mask); + } set_cpus_allowed_ptr(task, new_cpus); } css_task_iter_end(&it); -- 2.31.1