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 34AE2C433F5 for ; Tue, 16 Nov 2021 00:53:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18EF661B3B for ; Tue, 16 Nov 2021 00:53:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358784AbhKPA4R (ORCPT ); Mon, 15 Nov 2021 19:56:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:44626 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343540AbhKOTVS (ORCPT ); Mon, 15 Nov 2021 14:21:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 11E4A635AD; Mon, 15 Nov 2021 18:41:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1637001700; bh=aA7zCIUHOIkNJvWKO3490jiM+is53Y1ocJJDwBGLFgY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mBbaI/BjwhMo442da9ppwNxR2+jbLcNYoVwKJNRnr9OsLKQaKjTY7Psda30yjN09P 6tifQ1qgMErWE7KsZAh5zvTI2NYdJtSbSgeZFNEMXWC2vJ6LzD9cbT3JZhNizELV8K Hl6cU8LNNO4LA/sNiieasOAnMykEfvWHDQBAVTJo= 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 5.15 270/917] workqueue: make sysfs of unbound kworker cpumask more clever Date: Mon, 15 Nov 2021 17:56:05 +0100 Message-Id: <20211115165437.931344761@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165428.722074685@linuxfoundation.org> References: <20211115165428.722074685@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 1b3eb1e9531f4..76988f39ed5ac 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -5384,9 +5384,6 @@ 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. @@ -5394,6 +5391,15 @@ 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); @@ -5406,10 +5412,11 @@ 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