From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e3.ny.us.ibm.com (e3.ny.us.ibm.com [32.97.182.143]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e3.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 2C0F0B709C for ; Sat, 17 Jul 2010 04:33:35 +1000 (EST) Received: from d01relay07.pok.ibm.com (d01relay07.pok.ibm.com [9.56.227.147]) by e3.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id o6GIJBMr025308 for ; Fri, 16 Jul 2010 14:19:11 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay07.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o6GIXXJX1929348 for ; Fri, 16 Jul 2010 14:33:33 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o6GIXWqU004375 for ; Fri, 16 Jul 2010 15:33:32 -0300 Subject: Re: [PATCH 1/5] v2 Split the memory_block structure From: Dave Hansen To: Nathan Fontenot In-Reply-To: <4C40A3BC.3060504@austin.ibm.com> References: <4C3F53D1.3090001@austin.ibm.com> <4C3F557F.3000304@austin.ibm.com> <1279300521.9207.222.camel@nimitz> <4C40A3BC.3060504@austin.ibm.com> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Fri, 16 Jul 2010 11:33:30 -0700 Message-ID: <1279305210.9207.250.camel@nimitz> Mime-Version: 1.0 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki , linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2010-07-16 at 13:23 -0500, Nathan Fontenot wrote: > > If the memory_block's state was inferred to be the same as each > > memory_block_section, couldn't we just keep a start and end phys_index > > in the memory_block, and get away from having memory_block_sections at > > all? > > Oooohhh... I like. Looking at the code it appears this is possible. I'll > try this out and include it in the next version of the patch. > > Do you think we need to add an additional file to each memory block directory > to indicate the number of memory sections in the memory block that are actually > present? I think it's easiest to just say that each 'memory_block' can only hold contiguous 'memory_block_sections', and we give either the start/end or start/length pairs. It gets a lot more complicated if we have to deal with lots of holes. I can just see the hardware designers reading this thread, with their Dr. Evil laughs trying to come up with a reason to give us a couple of terabytes of RAM with only every-other 16MB area populated. :) -- Dave From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758896Ab0GPSdg (ORCPT ); Fri, 16 Jul 2010 14:33:36 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:55453 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758774Ab0GPSdd (ORCPT ); Fri, 16 Jul 2010 14:33:33 -0400 Subject: Re: [PATCH 1/5] v2 Split the memory_block structure From: Dave Hansen To: Nathan Fontenot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org, KAMEZAWA Hiroyuki In-Reply-To: <4C40A3BC.3060504@austin.ibm.com> References: <4C3F53D1.3090001@austin.ibm.com> <4C3F557F.3000304@austin.ibm.com> <1279300521.9207.222.camel@nimitz> <4C40A3BC.3060504@austin.ibm.com> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Fri, 16 Jul 2010 11:33:30 -0700 Message-ID: <1279305210.9207.250.camel@nimitz> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2010-07-16 at 13:23 -0500, Nathan Fontenot wrote: > > If the memory_block's state was inferred to be the same as each > > memory_block_section, couldn't we just keep a start and end phys_index > > in the memory_block, and get away from having memory_block_sections at > > all? > > Oooohhh... I like. Looking at the code it appears this is possible. I'll > try this out and include it in the next version of the patch. > > Do you think we need to add an additional file to each memory block directory > to indicate the number of memory sections in the memory block that are actually > present? I think it's easiest to just say that each 'memory_block' can only hold contiguous 'memory_block_sections', and we give either the start/end or start/length pairs. It gets a lot more complicated if we have to deal with lots of holes. I can just see the hardware designers reading this thread, with their Dr. Evil laughs trying to come up with a reason to give us a couple of terabytes of RAM with only every-other 16MB area populated. :) -- Dave From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 22BCB6B02A3 for ; Fri, 16 Jul 2010 14:33:38 -0400 (EDT) Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by e7.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id o6GIL1a7012657 for ; Fri, 16 Jul 2010 14:21:01 -0400 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o6GIXW3i1716346 for ; Fri, 16 Jul 2010 14:33:32 -0400 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o6GIXWqS004375 for ; Fri, 16 Jul 2010 15:33:32 -0300 Subject: Re: [PATCH 1/5] v2 Split the memory_block structure From: Dave Hansen In-Reply-To: <4C40A3BC.3060504@austin.ibm.com> References: <4C3F53D1.3090001@austin.ibm.com> <4C3F557F.3000304@austin.ibm.com> <1279300521.9207.222.camel@nimitz> <4C40A3BC.3060504@austin.ibm.com> Content-Type: text/plain; charset="ANSI_X3.4-1968" Date: Fri, 16 Jul 2010 11:33:30 -0700 Message-ID: <1279305210.9207.250.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Nathan Fontenot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@ozlabs.org, KAMEZAWA Hiroyuki List-ID: On Fri, 2010-07-16 at 13:23 -0500, Nathan Fontenot wrote: > > If the memory_block's state was inferred to be the same as each > > memory_block_section, couldn't we just keep a start and end phys_index > > in the memory_block, and get away from having memory_block_sections at > > all? > > Oooohhh... I like. Looking at the code it appears this is possible. I'll > try this out and include it in the next version of the patch. > > Do you think we need to add an additional file to each memory block directory > to indicate the number of memory sections in the memory block that are actually > present? I think it's easiest to just say that each 'memory_block' can only hold contiguous 'memory_block_sections', and we give either the start/end or start/length pairs. It gets a lot more complicated if we have to deal with lots of holes. I can just see the hardware designers reading this thread, with their Dr. Evil laughs trying to come up with a reason to give us a couple of terabytes of RAM with only every-other 16MB area populated. :) -- Dave -- 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/ . Don't email: email@kvack.org