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 442C6C433EF for ; Wed, 17 Nov 2021 15:57:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BF4860EE4 for ; Wed, 17 Nov 2021 15:57:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238876AbhKQQAA (ORCPT ); Wed, 17 Nov 2021 11:00:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:48408 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238859AbhKQP7y (ORCPT ); Wed, 17 Nov 2021 10:59:54 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1D7A761BFE; Wed, 17 Nov 2021 15:56:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1637164616; bh=z2E/+DyJF3ciNAiPoM8UMXFcWTkcpj8thvKrwqg0K6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=E8pMWFr3bFhS9blhvM9g+P9pcoqN5NMWkz/OmVg5dBdkgrmwe+htybTgdnWTVEB6k yC7kl2gqkkp2zWEDFi8omMT31o7K02H5fkiVQExd/WSZAa83O+1j2q6hGDM8OHvd4H lMxXe0+DudsPAzLBnz7LKM9mwdWbUF/W9n5pOuZk5WnTb3p0H1SE5EBWg4fpLVn9WL xjU+f3+FqaO+lF3CuqlqzvyLsK9R0P2EEmqmYonbPxZQt8TulkcHQ9geI0oF9qGMEa zkKDTcwUOWfi1H+l1tNO1/wnuD1wvRtdGZVTRIEOKn08Kp4CsKalDxzHYJU29p6PUb VW07LWGxynpLQ== From: Frederic Weisbecker To: "Paul E . McKenney" Cc: LKML , Frederic Weisbecker , Uladzislau Rezki , Neeraj Upadhyay , Boqun Feng , Josh Triplett , Joel Fernandes , rcu@vger.kernel.org Subject: [PATCH 5/6] rcu/nocb: Allow empty "rcu_nocbs" kernel parameter Date: Wed, 17 Nov 2021 16:56:36 +0100 Message-Id: <20211117155637.363706-6-frederic@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211117155637.363706-1-frederic@kernel.org> References: <20211117155637.363706-1-frederic@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If a user wants to boot without any CPU in offloaded mode initially but with the possibility to offload them later using cpusets, provide a way to simply pass an empty "rcu_nocbs" kernel parameter which will enforce the creation of dormant nocb kthreads. Signed-off-by: Frederic Weisbecker Cc: Neeraj Upadhyay Cc: Boqun Feng Cc: Uladzislau Rezki Cc: Josh Triplett Cc: Joel Fernandes --- kernel/rcu/tree_nocb.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index 1871f15b8472..3845f1885ffc 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -66,14 +66,16 @@ static bool rcu_nocb_is_setup; static int __init rcu_nocb_setup(char *str) { alloc_bootmem_cpumask_var(&rcu_nocb_mask); - if (cpulist_parse(str, rcu_nocb_mask)) { - pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n"); - cpumask_setall(rcu_nocb_mask); + if (*str == '=') { + if (cpulist_parse(++str, rcu_nocb_mask)) { + pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n"); + cpumask_setall(rcu_nocb_mask); + } } rcu_nocb_is_setup = true; return 1; } -__setup("rcu_nocbs=", rcu_nocb_setup); +__setup("rcu_nocbs", rcu_nocb_setup); static int __init parse_rcu_nocb_poll(char *arg) { -- 2.25.1