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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A24C0C4332F for ; Mon, 15 Nov 2021 18:42:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EE8963359 for ; Mon, 15 Nov 2021 18:42:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237861AbhKOSpH (ORCPT ); Mon, 15 Nov 2021 13:45:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:50338 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241816AbhKOSmq (ORCPT ); Mon, 15 Nov 2021 13:42:46 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B42B6632FE; Mon, 15 Nov 2021 18:05:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636999507; bh=6WjB2gY4tJ6GW3v1v03c1A1FQks9wvcVsAJiyjCtFBU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gS0mzc8r5xIqAsXL8Btczodu3GojVTu5gAA70ShCS6jtLh9y2vxx1tuZJlf/ki5Ix MG8RhNw8uyrHeaz1nMJj0Kv4xCji3teZKD9zu+MgjhuFrYBpBXckI67Bhg5rtcFKqf JLFYTS9lAdCzB4COnzgc0ojawCs22HlRd7uQ/bcM= 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 5.14 289/849] workqueue: make sysfs of unbound kworker cpumask more clever Date: Mon, 15 Nov 2021 17:56:12 +0100 Message-Id: <20211115165430.049243897@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165419.961798833@linuxfoundation.org> References: <20211115165419.961798833@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: stable@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 542c2d03dab65..ccad28bf21e26 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5340,9 +5340,6 @@ 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. @@ -5350,6 +5347,15 @@ 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); @@ -5362,10 +5368,11 @@ 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