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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3AC22C83F26 for ; Thu, 24 Jul 2025 18:36:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ZCg+1QoRbgtlHKqHHRGHpdwt2kaPrsylpaRAX7tlZ98=; b=IYXxWia8ijl92jiLY+FfTKIB5i W1w/0aAKQg6NcAITeuX9YpFCi1XdUfRphXoPo3oYKoQ9Dhu6yy63SBr6HLaANn6omjEiyZJdoz/KN D/q7akjy3XXQX5OtEWuwxOgoDUbDgDjLPu/smFymWgvjjgA6d5+OGpif+cWf8uR4PR8m2RkXSDC5m i3x8s2vMSGvfIoSGzG8PXXvoRHFlLQV7EY6R4B6j4veFT1VCELRhFpzSKfKkW62DLj4iqKnkj2S/J HtRi6+DjMAlor8VFRnwfgKhmaGOINMb0brjMBOnMXvhqukMpZstbyuI77if3W/qpuqU6XRREXd7/I +jAmz64g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uf0o6-00000008Dmf-1PUQ; Thu, 24 Jul 2025 18:36:42 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uf03L-000000089a4-10U9 for linux-arm-kernel@lists.infradead.org; Thu, 24 Jul 2025 17:48:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ZCg+1QoRbgtlHKqHHRGHpdwt2kaPrsylpaRAX7tlZ98=; b=kSRcuRqp2hSV2mCRQ5JKkdZmnI rChDz5dy7d9lgGVJ8iIjVuUvhVEi6Fj+1IhO1mNpVSnTSKrVDMuJBo5TxayvowmGemNxdNuWfx0GV 3Cgf65hQMP8zGV5ajpGa6GN/K9sJS1XqkQyEQQfPTOw8g09CWvnc+duS64f33U8AklDHI1SlKXz4H 4UOybKFir40fJsuqS68elFYqRNl5t4UDm0RRr2LMvzFwWtS0qtl2Xqtw2W6u08WH2SncRLmJ/Gz3e rVwf2vEn32V13KSb2CqvK5TAbTuZ1zW89R/mg9y2a/XCNj/65vE/jNeMXkGlpOj3Gozm+wfbJgCo6 vP4mgNRg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:40504) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uf014-0003co-15; Thu, 24 Jul 2025 18:46:02 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1uf00z-0000v7-0L; Thu, 24 Jul 2025 18:45:57 +0100 Date: Thu, 24 Jul 2025 18:45:56 +0100 From: "Russell King (Oracle)" To: Suchit Karunakaran Cc: ardb@kernel.org, linus.walleij@linaro.org, ebiggers@google.com, nathan@kernel.org, lumag@kernel.org, dave@vasilevsky.ca, ruanjinjie@huawei.com, kees@kernel.org, liuyuntao12@huawei.com, linux-arm-kernel@lists.infradead.org, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm: allow single CPU configuration by adjusting NR_CPUS range and defaults Message-ID: References: <20250724172603.18701-1-suchitkarunakaran@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250724172603.18701-1-suchitkarunakaran@gmail.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250724_104823_280519_F30BC6AE X-CRM114-Status: GOOD ( 10.86 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Jul 24, 2025 at 10:56:03PM +0530, Suchit Karunakaran wrote: > Previously, the NR_CPUS config for ARM required a minimum of 2 CPUs. > This patch changes the minimum NR_CPUS to 1 when SMP is not enabled, > sets range to exactly 1 if !SMP, allowing only a single CPU setting and > adds conditional defaults: > - default to 1 if SMP is disabled (uniprocessor) > - default to 4 if SMP is enabled (multiprocessor) > > Signed-off-by: Suchit Karunakaran This hasn't been tested. NR_CPUS depends on SMP, so if SMP is not enabled, then NR_CPUS doesn't exist in the configuration. Therefore, providing a default for !SMP is meaningless. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!