From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-gx0-f21.google.com (mail-gx0-f21.google.com [209.85.217.21]) by ozlabs.org (Postfix) with ESMTP id B2857DDF44 for ; Thu, 25 Sep 2008 02:08:46 +1000 (EST) Received: by gxk14 with SMTP id 14so5657224gxk.9 for ; Wed, 24 Sep 2008 09:08:44 -0700 (PDT) Message-ID: Date: Wed, 24 Sep 2008 11:08:44 -0500 From: "Timur Tabi" Sender: timur.tabi@gmail.com To: "Johannes Berg" Subject: Re: [PATCH v2] powerpc: enforce sane MAX_ORDER In-Reply-To: <1222266548.4257.26.camel@johannes.berg> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 References: <1222262654.4257.4.camel@johannes.berg> <1222265583.4257.21.camel@johannes.berg> <61059ECE-2B42-46B3-B5B3-E5CFA3A5EFC9@kernel.crashing.org> <1222266548.4257.26.camel@johannes.berg> Cc: linuxppc-dev list , Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Sep 24, 2008 at 9:29 AM, Johannes Berg wrote: > Indeed, it makes little sense to allow you to set more than the address > space, so here's a version with max 64. Acked-by: Timur Tabi However, the max is actually less than 64. Assuming a 64-bit address space, the maximum number of pages in one allocation can be 2^(64-PAGE_SHIFT). For 4KB pages, the max value for FORCE_MAX_ZONEORDER is 53. For 64KB pages, the max is 49. -- Timur Tabi Linux kernel developer at Freescale