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 BE9FCC433F5 for ; Tue, 16 Nov 2021 02:08:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B9D161360 for ; Tue, 16 Nov 2021 02:08:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349409AbhKPCLp (ORCPT ); Mon, 15 Nov 2021 21:11:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:40774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238908AbhKOR7Q (ORCPT ); Mon, 15 Nov 2021 12:59:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E8642632CD; Mon, 15 Nov 2021 17:35:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636997737; bh=wtnOxFHU44filqddQzw5KkDsIsaeifUehuCZof6zjOU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wm0tPbUV/fUXP6YwmUxtEHBnAoGKJf33VbnR//bVjFUeC5i+d/pmcctiW56HEpJsF Tt/jYnGXdC40lxac5Rlo8lDKMQ4HOHkFDutmoyR6BKRseIXvcduy59N32lunNEKalz 1qDRJ8e3ZAtGf+GhryGO+wIEi08rUYXxleCqIVLE= 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 5.10 224/575] workqueue: make sysfs of unbound kworker cpumask more clever Date: Mon, 15 Nov 2021 17:59:09 +0100 Message-Id: <20211115165351.459731622@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165343.579890274@linuxfoundation.org> References: <20211115165343.579890274@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 4cb622b2661b5..d02073b9d56e2 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5326,9 +5326,6 @@ 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. @@ -5336,6 +5333,15 @@ 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); @@ -5348,10 +5354,11 @@ 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