Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759701Ab2FAM4u (ORCPT ); Fri, 1 Jun 2012 08:56:50 -0400 Received: from e28smtp01.in.ibm.com ([122.248.162.1]:49433 "EHLO e28smtp01.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759671Ab2FAM4t (ORCPT ); Fri, 1 Jun 2012 08:56:49 -0400 Message-ID: <4FC8BBBF.6090701@linux.vnet.ibm.com> Date: Fri, 01 Jun 2012 18:25:27 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120424 Thunderbird/12.0 MIME-Version: 1.0 To: Russell King - ARM Linux CC: "linux-kernel@vger.kernel.org" , Hirokazu Takata , Richard Kuo , David Howells , Bob Liu , "David S. Miller" , Richard Weinberger , Jesper Nilsson , "James E.J. Bottomley" , Martin Schwidefsky , Matt Turner , nikunj@linux.vnet.ibm.com Subject: Re: [PATCH 03/27] smpboot: Define and use cpu_state per-cpu variable in generic code References: <20120601090952.31979.24799.stgit@srivatsabhat.in.ibm.com> <20120601091038.31979.67878.stgit@srivatsabhat.in.ibm.com> <4FC8B342.9070309@linux.vnet.ibm.com> <20120601122554.GA25595@n2100.arm.linux.org.uk> In-Reply-To: <20120601122554.GA25595@n2100.arm.linux.org.uk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 12060112-4790-0000-0000-0000030A579A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1417 Lines: 40 On 06/01/2012 05:55 PM, Russell King - ARM Linux wrote: > On Fri, Jun 01, 2012 at 05:49:14PM +0530, Srivatsa S. Bhat wrote: >> Adding arch maintainers to Cc, which I had missed earlier. No changes to the >> patch. > > Could someone explain what this variable does - afaics this patch adds > this per-cpu variable to all SMP architectures where its required or > not, and (so far) the generic code just writes one value to it. > Several architectures use this per-cpu variable to track the state of the cpu (like CPU_DEAD), particularly to deal with cpu offline. (At this point, we have just tried to generalize code without any major functional changes.) > Are there plans to make use of this in other generic code? > The idea of this patchset is to make smp booting and cpu hotplug code as generic as possible and eventually have _one_ implementation in the generic code which can be reused by all architectures that want it. And this patchset generalizes only the booting of secondary cpus. But in future, we can use this as a base and implement cpu hotplug handling in generic code, where this variable will become more useful. Regards, Srivatsa S. Bhat -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/