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 3852CC43217 for ; Wed, 24 Nov 2021 12:59:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346475AbhKXNCZ (ORCPT ); Wed, 24 Nov 2021 08:02:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:41112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346754AbhKXNAU (ORCPT ); Wed, 24 Nov 2021 08:00:20 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3A68661175; Wed, 24 Nov 2021 12:34:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637757270; bh=ufrqD5GM6BCWE6ozeSLbaaPWgc65jOD7AnWNkV4ajrQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cMtOLrc2JOj6/Durfdp9WeD2JHjE9CP3yKepjlcHx4N68W2CqDdPSw89a9nT0ABNA X5xfqYGJiCjVTRY/BwtfyNgcnhhWTGtc/BiMs5N5Ah4GLNr1TiQTyjLYw6dQHVsckI LTXnOW9wpZWBmlQlwzG6OI5AkNXsqu7tX3oib3z0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mengen Sun , Menglong Dong , Tejun Heo , Sasha Levin Subject: [PATCH 4.19 112/323] workqueue: make sysfs of unbound kworker cpumask more clever Date: Wed, 24 Nov 2021 12:55:02 +0100 Message-Id: <20211124115722.737647454@linuxfoundation.org> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124115718.822024889@linuxfoundation.org> References: <20211124115718.822024889@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Menglong Dong [ Upstream commit d25302e46592c97d29f70ccb1be558df31a9a360 ] Some unfriendly component, such as dpdk, write the same mask to unbound kworker cpumask again and again. Every time it write to this interface some work is queue to cpu, even though the mask is same with the original mask. So, fix it by return success and do nothing if the cpumask is equal with the old one. Signed-off-by: Mengen Sun Signed-off-by: Menglong Dong Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- kernel/workqueue.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1573d1bf63007..b1bb6cb5802ec 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5125,9 +5125,6 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) int ret = -EINVAL; cpumask_var_t saved_cpumask; - if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) - return -ENOMEM; - /* * Not excluding isolated cpus on purpose. * If the user wishes to include them, we allow that. @@ -5135,6 +5132,15 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) cpumask_and(cpumask, cpumask, cpu_possible_mask); if (!cpumask_empty(cpumask)) { apply_wqattrs_lock(); + if (cpumask_equal(cpumask, wq_unbound_cpumask)) { + ret = 0; + goto out_unlock; + } + + if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) { + ret = -ENOMEM; + goto out_unlock; + } /* save the old wq_unbound_cpumask. */ cpumask_copy(saved_cpumask, wq_unbound_cpumask); @@ -5147,10 +5153,11 @@ int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) if (ret < 0) cpumask_copy(wq_unbound_cpumask, saved_cpumask); + free_cpumask_var(saved_cpumask); +out_unlock: apply_wqattrs_unlock(); } - free_cpumask_var(saved_cpumask); return ret; } -- 2.33.0