Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422839AbWBIQ7e (ORCPT ); Thu, 9 Feb 2006 11:59:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422891AbWBIQ7e (ORCPT ); Thu, 9 Feb 2006 11:59:34 -0500 Received: from proof.pobox.com ([207.106.133.28]:56793 "EHLO proof.pobox.com") by vger.kernel.org with ESMTP id S1422872AbWBIQ7d (ORCPT ); Thu, 9 Feb 2006 11:59:33 -0500 Date: Thu, 9 Feb 2006 10:59:22 -0600 From: Nathan Lynch To: Heiko Carstens Cc: Andrew Morton , Eric Dumazet , riel@redhat.com, linux-kernel@vger.kernel.org, torvalds@osdl.org, mingo@elte.hu, ak@muc.de, 76306.1226@compuserve.com, wli@holomorphy.com, Paul Jackson Subject: Re: [PATCH] percpu data: only iterate over possible CPUs Message-ID: <20060209165922.GM18730@localhost.localdomain> References: <200602051959.k15JxoHK001630@hera.kernel.org> <20060208190512.5ebcdfbe.akpm@osdl.org> <20060208190839.63c57a96.akpm@osdl.org> <43EAC6BE.2060807@cosmosbay.com> <20060208204502.12513ae5.akpm@osdl.org> <20060209160808.GL18730@localhost.localdomain> <20060209161331.GE20554@osiris.boeblingen.de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060209161331.GE20554@osiris.boeblingen.de.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 983 Lines: 19 Heiko Carstens wrote: > > > Presumably not all architectures are doing that. > > powerpc/ppc64, for instance, determines the number of possible cpus > > from information exported by firmware (and I'm mystified as to why > > other platforms don't do this). So it's typical to have a kernel an a > > pSeries partition with NR_CPUS=128, but cpu_possible_map = 0xff. > > Simply because there is no such interface on s390. The only thing we know > for sure is that if we are running under z/VM the user is free to > configure up to 63 additional virtual cpus on the fly... My "mystified" parenthetical was not meant as a criticism of arch/!powerpc, but of the platform implementations themselves, for not making such an interface available. - 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/