Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755562AbYGKRRr (ORCPT ); Fri, 11 Jul 2008 13:17:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754131AbYGKRRi (ORCPT ); Fri, 11 Jul 2008 13:17:38 -0400 Received: from terminus.zytor.com ([198.137.202.10]:53264 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753554AbYGKRRi (ORCPT ); Fri, 11 Jul 2008 13:17:38 -0400 Message-ID: <48779411.1080909@zytor.com> Date: Fri, 11 Jul 2008 13:10:41 -0400 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: "Eric W. Biederman" CC: Christoph Lameter , Mike Travis , Jeremy Fitzhardinge , Arjan van de Ven , Ingo Molnar , Andrew Morton , Jack Steiner , linux-kernel@vger.kernel.org, Rusty Russell Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses References: <20080709165129.292635000@polaris-admin.engr.sgi.com> <20080709200757.GD14009@elte.hu> <48751B57.8030605@goop.org> <20080709133958.612635f0@infradead.org> <4875231F.1020506@zytor.com> <487524A0.6020304@goop.org> <487529AE.3060505@zytor.com> <48753A71.2030006@zytor.com> <48763732.7020805@sgi.com> <487641D6.5060206@goop.org> <487649B2.3000405@sgi.com> <48764E8A.5010400@zytor.com> <4876766F.4030605@linux-foundation.org> <48767804.8080007@zytor.com> <48767A28.7070900@linux-foundation.org> <48767AF5.7030205@zytor.com> <48777D15.6040107@linux-foundation.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 710 Lines: 19 Eric W. Biederman wrote: >> x86_64 are small systems? For 64 bit use one would expect 4GB of memory. > > Anything over 1G where 32bit runs out of lowmem starts to be a win. > Plus sometimes it just doesn't make sense to use a 32bit kernel. > > Expecting 4GB of real memory seems silly. Especially since people set up VM instances small and then grow them. They can have *weird* CPU-to-RAM ratios; I have heard of 8 VCPUs and 24 MB of RAM in production. -hpa -- 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/