From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760054Ab1D0VmX (ORCPT ); Wed, 27 Apr 2011 17:42:23 -0400 Received: from am1ehsobe002.messaging.microsoft.com ([213.199.154.205]:57220 "EHLO AM1EHSOBE002.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759270Ab1D0VmW (ORCPT ); Wed, 27 Apr 2011 17:42:22 -0400 X-SpamScore: -9 X-BigFish: VS-9(zz1432N98dKzz1202hzzz2dh2a8h668h839h61h) X-Spam-TCS-SCL: 0:0 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPVD:NLI;H:mail.freescale.net;RD:none;EFVD:NLI Message-ID: <4DB88DAF.2010504@freescale.com> Date: Wed, 27 Apr 2011 16:42:07 -0500 From: Timur Tabi Organization: Freescale User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.18) Gecko/20110410 Fedora/2.0.13-1.fc13 SeaMonkey/2.0.13 MIME-Version: 1.0 To: Dave Hansen CC: , , Andi Kleen , Mel Gorman , Andrew Morton , Michal Nazarewicz , David Rientjes Subject: Re: [PATCH 2/3] make new alloc_pages_exact() References: <20110414200139.ABD98551@kernel> <20110414200140.CDE09A20@kernel> <4DB88AF0.1050501@freescale.com> <1303940249.9516.366.camel@nimitz> In-Reply-To: <1303940249.9516.366.camel@nimitz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Hansen wrote: >> Is there an easy way to verify that alloc_pages_exact(5MB) really does allocate >> > only 5MB and not 8MB? > I'm not sure why you're asking. How do we know that the _normal_ > allocator only gives us 4k when we ask for 4k? Well, that's just how it > works. If alloc_pages_exact() returns success, you know it's got the > amount of memory that you asked for, and only that plus a bit of masking > for page alignment. > > Have you seen alloc_pages_exact() behaving in some other way? I've never tested this part of alloc_pages_exact(), even when I wrote (the first version of) it. I just took it on faith that it actually did what it was supposed to do. -- Timur Tabi Linux kernel developer at Freescale From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id 360436B0011 for ; Wed, 27 Apr 2011 17:42:24 -0400 (EDT) Message-ID: <4DB88DAF.2010504@freescale.com> Date: Wed, 27 Apr 2011 16:42:07 -0500 From: Timur Tabi MIME-Version: 1.0 Subject: Re: [PATCH 2/3] make new alloc_pages_exact() References: <20110414200139.ABD98551@kernel> <20110414200140.CDE09A20@kernel> <4DB88AF0.1050501@freescale.com> <1303940249.9516.366.camel@nimitz> In-Reply-To: <1303940249.9516.366.camel@nimitz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andi Kleen , Mel Gorman , Andrew Morton , Michal Nazarewicz , David Rientjes Dave Hansen wrote: >> Is there an easy way to verify that alloc_pages_exact(5MB) really does allocate >> > only 5MB and not 8MB? > I'm not sure why you're asking. How do we know that the _normal_ > allocator only gives us 4k when we ask for 4k? Well, that's just how it > works. If alloc_pages_exact() returns success, you know it's got the > amount of memory that you asked for, and only that plus a bit of masking > for page alignment. > > Have you seen alloc_pages_exact() behaving in some other way? I've never tested this part of alloc_pages_exact(), even when I wrote (the first version of) it. I just took it on faith that it actually did what it was supposed to do. -- Timur Tabi Linux kernel developer at Freescale -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org