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[209.132.180.67]) by mx.google.com with ESMTP id e129si2761194pfe.87.2018.03.21.02.09.54; Wed, 21 Mar 2018 02:10:08 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=merlin.20170209 header.b=a86tu4xZ; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751920AbeCUJIr (ORCPT + 99 others); Wed, 21 Mar 2018 05:08:47 -0400 Received: from merlin.infradead.org ([205.233.59.134]:44634 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751879AbeCUJIp (ORCPT ); Wed, 21 Mar 2018 05:08:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender: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=1jxnvD4a+l9wEc3POvF0++9liQLWiHPIP8cGKPt8kL8=; b=a86tu4xZAjG1ffkDu8HWUIAfy 4lBPGAfXY1tcTSCugX+AAJlS/v0b7or+pBid2ZT+SGnMuMbA2SV8Qzom1GSBCNPa8iyGguMfcY/Pz XjWh8EN2WNau3kmpXkoumM03srYeGRFM0INsIkat0fWw88BKS4O22T6tQHM9pR/R0TnW7zeVJirCN 3KimwQ1ZeJfmDRcv3Jv2L0C+PlGqA5kZJI4+D7C6xklTU61C/s5L+xaJC18Xk8hhdrMUCqKtawLsg eSTlsE3d8yxzSZucfXjNTla0Nw0iokfuveSpNL0UPJrrDyD3DI31Cz1YYo/wDlrIFM8oMBlwX8vwH j5U0Fy9Rw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1eyZjQ-0006Mf-0U; Wed, 21 Mar 2018 09:08:28 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7D0C6202A29FD; Wed, 21 Mar 2018 10:08:26 +0100 (CET) Date: Wed, 21 Mar 2018 10:08:26 +0100 From: Peter Zijlstra To: Dou Liyang Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-acpi@vger.kernel.org, linux-doc@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, corbet@lwn.net, rjw@rjwysocki.net, lenb@kernel.org, hpa@zytor.com Subject: Re: [PATCH 1/5] x86/smpboot: Add the missing description of possible_cpus Message-ID: <20180321090826.GW4043@hirez.programming.kicks-ass.net> References: <20180320110432.28127-1-douly.fnst@cn.fujitsu.com> <20180320110432.28127-2-douly.fnst@cn.fujitsu.com> <20180320123712.GR4043@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 21, 2018 at 01:33:24PM +0800, Dou Liyang wrote: > How about: > > possible_cpus= [s390,x86_64] Set the number of possible CPUs which > are determined by the ACPI tables MADT or mptables by > default. possible_cpus=n : n >= 1 enforces the possible > number to be 'n'. > While nr_cpus is also be set: nr_cpus=m, choice the > minimum one for the number of possible CPUs. So what is the exact difference between possible_cpus and nr_cpus ? I konw maxcpus= limits the number of CPUs we bring up, and possible_cpus limits the possible_map, but I'm not entirely sure what nr_cpus does here.