From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2A5AEB64DD for ; Wed, 5 Jul 2023 03:14:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229951AbjGEDO4 (ORCPT ); Tue, 4 Jul 2023 23:14:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229744AbjGEDOx (ORCPT ); Tue, 4 Jul 2023 23:14:53 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 073CE1B6 for ; Tue, 4 Jul 2023 20:14:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688526846; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=nrkEIq6dhRR9ar//G8iVT0D1nMSlQSq+xiDuYGm9BDg=; b=hcZF4f+B+aGPV4zsvmbDuRpL2WQXvk/HdzXSiWpJQdUpFdRuiglLVimMtlOEkWMazizC9m 7ZaxaHiBlVfE2jWKeqjgIu2ZdBtJDdOthrBAOI3evvdsL/jQn9I82oUNIgbh4H8zBhIhZB UdBv1ZV8BSuKNO6ZVWXTynINoh1XqxI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-111-67tYLv16ODq-ae5T52CHXA-1; Tue, 04 Jul 2023 23:14:02 -0400 X-MC-Unique: 67tYLv16ODq-ae5T52CHXA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 95B3D3806060; Wed, 5 Jul 2023 03:14:01 +0000 (UTC) Received: from [10.22.16.39] (unknown [10.22.16.39]) by smtp.corp.redhat.com (Postfix) with ESMTP id 51F374087C6A; Wed, 5 Jul 2023 03:14:01 +0000 (UTC) Message-ID: Date: Tue, 4 Jul 2023 23:14:01 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.7.1 Subject: Re: [PATCH] cgroup/cpuset: simplify the percpu kthreads check in update_tasks_cpumask() Content-Language: en-US To: Miaohe Lin , tj@kernel.org, hannes@cmpxchg.org, lizefan.x@bytedance.com Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230704113049.1019118-1-linmiaohe@huawei.com> From: Waiman Long In-Reply-To: <20230704113049.1019118-1-linmiaohe@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/4/23 07:30, Miaohe Lin wrote: > kthread_is_per_cpu() can be called directly without checking whether > PF_KTHREAD is set in task->flags. So remove PF_KTHREAD check to make > code more concise. > > Signed-off-by: Miaohe Lin > --- > kernel/cgroup/cpuset.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 58e6f18f01c1..601c40da8e03 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -1230,7 +1230,7 @@ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) > /* > * Percpu kthreads in top_cpuset are ignored > */ > - if ((task->flags & PF_KTHREAD) && kthread_is_per_cpu(task)) > + if (kthread_is_per_cpu(task)) > continue; > cpumask_andnot(new_cpus, possible_mask, cs->subparts_cpus); > } else { The initial intention was to ignore only percpu kthreads. The current code likely ignore all the kthreads. Removing the PF_KTHREAD flag, however, may introduce unexpected regression at this point. I would like to hold off for now until more investigation are done. Thanks, Longman