From nobody Sun Feb 8 18:32:56 2026 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 24584EB64D8 for ; Thu, 22 Jun 2023 03:34:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229865AbjFVDeb (ORCPT ); Wed, 21 Jun 2023 23:34:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229513AbjFVDe2 (ORCPT ); Wed, 21 Jun 2023 23:34:28 -0400 Received: from mx5.didiglobal.com (mx5.didiglobal.com [111.202.70.122]) by lindbergh.monkeyblade.net (Postfix) with SMTP id 599D41BD4 for ; Wed, 21 Jun 2023 20:34:26 -0700 (PDT) Received: from mail.didiglobal.com (unknown [10.79.65.12]) by mx5.didiglobal.com (Maildata Gateway V2.8) with ESMTPS id 9A257B007D639; Thu, 22 Jun 2023 11:34:24 +0800 (CST) Received: from didi-ThinkCentre-M930t-N000 (10.79.64.101) by ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Thu, 22 Jun 2023 11:34:24 +0800 Date: Thu, 22 Jun 2023 11:34:09 +0800 X-MD-Sfrom: tiozhang@didiglobal.com X-MD-SrcIP: 10.79.65.12 From: tiozhang To: CC: , , , , , Subject: [PATCH] workqueue: add cmdline parameter `unbound_workqueue_cpus` to further constrain wq_unbound_cpumask at boot time Message-ID: <20230622033353.GA29115@didi-ThinkCentre-M930t-N000> Mail-Followup-To: tj@kernel.org, jiangshanlai@gmail.com, linux-kernel@vger.kernel.org, zyhtheonly@yeah.net, zwp10758@gmail.com, zyhtheonly@gmail.com MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Originating-IP: [10.79.64.101] X-ClientProxiedBy: ZJY01-PUBMBX-01.didichuxing.com (10.79.64.32) To ZJY02-ACTMBX-02.didichuxing.com (10.79.65.12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Motivation of doing this is to better improve boot times for devices when we want to prevent our workqueue works from running on some specific CPUs, e,g, some CPUs are busy with interrupts. Signed-off-by: tiozhang --- kernel/workqueue.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 7cd5f5e7e0a1..47e7b29df5fe 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -329,6 +329,9 @@ static bool workqueue_freezing; /* PL: have wqs starte= d freezing? */ /* PL: allowable cpus for unbound wqs and work items */ static cpumask_var_t wq_unbound_cpumask; =20 +/* for further constrain wq_unbound_cpumask by cmdline parameter*/ +static cpumask_var_t wq_cmdline_cpumask; + /* CPU where unbound work was last round robin scheduled from this CPU */ static DEFINE_PER_CPU(int, wq_rr_cpu_last); =20 @@ -6006,6 +6009,10 @@ void __init workqueue_init_early(void) cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ)); cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(= HK_TYPE_DOMAIN)); =20 + if (!cpumask_empty(wq_cmdline_cpumask)) + cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, wq_cmdline_cpumask); + free_bootmem_cpumask_var(wq_cmdline_cpumask); + pwq_cache =3D KMEM_CACHE(pool_workqueue, SLAB_PANIC); =20 /* initialize CPU pools */ @@ -6129,3 +6136,21 @@ void __init workqueue_init(void) */ void __warn_flushing_systemwide_wq(void) { } EXPORT_SYMBOL(__warn_flushing_systemwide_wq); + + +static int __init unbound_workqueue_cpus_setup(char *str) +{ + cpumask_var_t cpumask; + + alloc_bootmem_cpumask_var(&wq_cmdline_cpumask); + alloc_bootmem_cpumask_var(&cpumask); + if (cpulist_parse(str, cpumask) < 0) + pr_warn("unbound_workqueue_cpus: incorrect CPU range\n"); + else + cpumask_copy(wq_cmdline_cpumask, cpumask); + + free_bootmem_cpumask_var(cpumask); + + return 0; +} +__setup("unbound_workqueue_cpus=3D", unbound_workqueue_cpus_setup); --=20 2.17.1