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 0F08BC433EF for ; Tue, 28 Dec 2021 08:05:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232115AbhL1IFE (ORCPT ); Tue, 28 Dec 2021 03:05:04 -0500 Received: from mga02.intel.com ([134.134.136.20]:21737 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230489AbhL1IFB (ORCPT ); Tue, 28 Dec 2021 03:05:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1640678701; x=1672214701; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=VXX/GSUjwDrw6yMUS3z5rSKLlRpeGlqj+gglNGqtlnI=; b=QMMC7qqI0ZyjW+L36i4vj63y5OlqOL7V0vzmQWeok8OHdVf/P+T/MpXk GOkZk3tYkgs5SMBgsp69EwFvKqHlXsW/INXM3kRn/2JN37mUCr0JpxvtU DPoi88IlH2zNZSgb40h8hWP/LEGESaYrWczenYnLKW4jbYIGM7fMNQrCL gOxXGT0hhNiExlXDMnoFTFn3ZdkwWZSkt7Hs/kByuCZLeg34fbIy7yqT8 vBCNg6PwpdbBN69JV5Vo964OqsGE4QmjPEGaIWS8uz0d4uT5d7xYIXMbF AruuIw8LunBn9F8FyAofGlLkIK0frPYPBAGPwcGnQkgRmPEPd7qmlpJ0R Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10210"; a="228634844" X-IronPort-AV: E=Sophos;i="5.88,241,1635231600"; d="scan'208";a="228634844" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Dec 2021 00:05:01 -0800 X-IronPort-AV: E=Sophos;i="5.88,241,1635231600"; d="scan'208";a="686525921" Received: from unknown (HELO zq-OptiPlex-7090.bj.intel.com) ([10.238.156.125]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Dec 2021 00:04:59 -0800 From: Zqiang To: paulmck@kernel.org, frederic@kernel.org Cc: linux-kernel@vger.kernel.org, qiang1.zhang@intel.com Subject: [PATCH] rcu: per-cpu rcuc kthread are created only when rcutree.use_softirq=0 Date: Wed, 29 Dec 2021 00:05:10 +0800 Message-Id: <20211228160510.2893362-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In non-RT kernel, if the RCU_BOOST is enabled, the per-cpu rcuc kthread will be created, however under the rcutree.use_softirq=1, the RCU core processing only in softirq context, the rcuc kthread doesn't do anything, so remove RCU_BOOST interference. Signed-off-by: Zqiang --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 9b58bae0527a..ed64b4fcb8a0 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2902,7 +2902,7 @@ static int __init rcu_spawn_core_kthreads(void) for_each_possible_cpu(cpu) per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0; - if (!IS_ENABLED(CONFIG_RCU_BOOST) && use_softirq) + if (use_softirq) return 0; WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec), "%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__); -- 2.25.1