Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932722Ab2JKOl4 (ORCPT ); Thu, 11 Oct 2012 10:41:56 -0400 Received: from mail-qa0-f53.google.com ([209.85.216.53]:60079 "EHLO mail-qa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751069Ab2JKOlq (ORCPT ); Thu, 11 Oct 2012 10:41:46 -0400 Date: Thu, 11 Oct 2012 10:41:32 -0400 From: Konrad Rzeszutek Wilk To: Yinghai Lu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jacob Shin , Tejun Heo , Stefano Stabellini , linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/10] x86, mm: get early page table from BRK Message-ID: <20121011144130.GB2408@localhost.localdomain> References: <1349757558-10856-1-git-send-email-yinghai@kernel.org> <1349757558-10856-4-git-send-email-yinghai@kernel.org> <20121009160133.GF7639@phenom.dumpdata.com> <20121010141707.GH4005@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1071 Lines: 28 On Wed, Oct 10, 2012 at 08:49:05AM -0700, Yinghai Lu wrote: > On Wed, Oct 10, 2012 at 7:17 AM, Konrad Rzeszutek Wilk > wrote: > > On Tue, Oct 09, 2012 at 06:03:33PM -0700, Yinghai Lu wrote: > > >> good point, i add one line comment to the revised patch. > >> > >> +/* need 3 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */ > > > > Can you explain the math please? It sounds like this is based on > > the assumption that this you are using huge pages. But what if you > > are not? What if you can only do 4KB pages? > > yes that is some extreme case: > assume that 2M range is [2T-2M, 2T), What is T in here? Terabyte? Is the '[' vs ')' a significance in your explanation? Should it be '[2T-2M, 2T]' ? > one page for PGD-[2T-512g, 2T), one for PUD - [2T-1G, 2T), and one for > PMD -: [2T-2M, 2T) -- 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/