From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754083Ab1FOIg7 (ORCPT ); Wed, 15 Jun 2011 04:36:59 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:25354 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754002Ab1FOIgx (ORCPT ); Wed, 15 Jun 2011 04:36:53 -0400 Date: Wed, 15 Jun 2011 10:36:18 +0200 From: Marek Szyprowski Subject: RE: [Linaro-mm-sig] [PATCH 08/10] mm: cma: Contiguous Memory Allocator added In-reply-to: <201106142242.25157.arnd@arndb.de> To: "'Arnd Bergmann'" , "'Zach Pfeffer'" Cc: linux-arm-kernel@lists.infradead.org, "'Daniel Walker'" , "'Daniel Stone'" , linux-mm@kvack.org, "'Mel Gorman'" , linux-kernel@vger.kernel.org, "'Michal Nazarewicz'" , linaro-mm-sig@lists.linaro.org, "'Jesse Barker'" , "'Kyungmin Park'" , "'Ankita Garg'" , "'Andrew Morton'" , "'KAMEZAWA Hiroyuki'" , linux-media@vger.kernel.org, Marek Szyprowski Message-id: <000901cc2b37$4c21f030$e465d090$%szyprowski@samsung.com> Organization: SPRC MIME-version: 1.0 X-Mailer: Microsoft Office Outlook 12.0 Content-type: text/plain; charset=us-ascii Content-language: pl Content-transfer-encoding: 7BIT Thread-index: Acwq08w+hLuENvqsQ6WxCs8SVZBnZAAV+1Dg References: <1307699698-29369-1-git-send-email-m.szyprowski@samsung.com> <20110614170158.GU2419@fooishbar.org> <201106142242.25157.arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tuesday, June 14, 2011 10:42 PM Arnd Bergmann wrote: > On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote: > > I've seen this split bank allocation in Qualcomm and TI SoCs, with > > Samsung, that makes 3 major SoC vendors (I would be surprised if > > Nvidia didn't also need to do this) - so I think some configurable > > method to control allocations is necessarily. The chips can't do > > decode without it (and by can't do I mean 1080P and higher decode is > > not functionally useful). Far from special, this would appear to be > > the default. > > Thanks for the insight, that's a much better argument than 'something > may need it'. Are those all chips without an IOMMU or do we also > need to solve the IOMMU case with split bank allocation? > > I think I'd still prefer to see the support for multiple regions split > out into one of the later patches, especially since that would defer > the question of how to do the initialization for this case and make > sure we first get a generic way. > > You've convinced me that we need to solve the problem of allocating > memory from a specific bank eventually, but separating it from the > one at hand (contiguous allocation) should help getting the important > groundwork in at first. > > The possible conflict that I still see with per-bank CMA regions are: > > * It completely destroys memory power management in cases where that > is based on powering down entire memory banks. I don't think that per-bank CMA regions destroys memory power management more than the global CMA pool. Please note that the contiguous buffers (or in general dma-buffers) right now are unmovable so they don't fit well into memory power management. Best regards -- Marek Szyprowski Samsung Poland R&D Center From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id BE2766B0012 for ; Wed, 15 Jun 2011 04:36:53 -0400 (EDT) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Received: from eu_spt1 ([210.118.77.14]) by mailout4.w1.samsung.com (Sun Java(tm) System Messaging Server 6.3-8.04 (built Jul 29 2009; 32bit)) with ESMTP id <0LMT005SRP9EMY40@mailout4.w1.samsung.com> for linux-mm@kvack.org; Wed, 15 Jun 2011 09:36:51 +0100 (BST) Received: from linux.samsung.com ([106.116.38.10]) by spt1.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0LMT00DQMP9DM1@spt1.w1.samsung.com> for linux-mm@kvack.org; Wed, 15 Jun 2011 09:36:50 +0100 (BST) Date: Wed, 15 Jun 2011 10:36:18 +0200 From: Marek Szyprowski Subject: RE: [Linaro-mm-sig] [PATCH 08/10] mm: cma: Contiguous Memory Allocator added In-reply-to: <201106142242.25157.arnd@arndb.de> Message-id: <000901cc2b37$4c21f030$e465d090$%szyprowski@samsung.com> Content-language: pl References: <1307699698-29369-1-git-send-email-m.szyprowski@samsung.com> <20110614170158.GU2419@fooishbar.org> <201106142242.25157.arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: 'Arnd Bergmann' , 'Zach Pfeffer' Cc: linux-arm-kernel@lists.infradead.org, 'Daniel Walker' , 'Daniel Stone' , linux-mm@kvack.org, 'Mel Gorman' , linux-kernel@vger.kernel.org, 'Michal Nazarewicz' , linaro-mm-sig@lists.linaro.org, 'Jesse Barker' , 'Kyungmin Park' , 'Ankita Garg' , 'Andrew Morton' , 'KAMEZAWA Hiroyuki' , linux-media@vger.kernel.org, Marek Szyprowski Hello, On Tuesday, June 14, 2011 10:42 PM Arnd Bergmann wrote: > On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote: > > I've seen this split bank allocation in Qualcomm and TI SoCs, with > > Samsung, that makes 3 major SoC vendors (I would be surprised if > > Nvidia didn't also need to do this) - so I think some configurable > > method to control allocations is necessarily. The chips can't do > > decode without it (and by can't do I mean 1080P and higher decode is > > not functionally useful). Far from special, this would appear to be > > the default. > > Thanks for the insight, that's a much better argument than 'something > may need it'. Are those all chips without an IOMMU or do we also > need to solve the IOMMU case with split bank allocation? > > I think I'd still prefer to see the support for multiple regions split > out into one of the later patches, especially since that would defer > the question of how to do the initialization for this case and make > sure we first get a generic way. > > You've convinced me that we need to solve the problem of allocating > memory from a specific bank eventually, but separating it from the > one at hand (contiguous allocation) should help getting the important > groundwork in at first. > > The possible conflict that I still see with per-bank CMA regions are: > > * It completely destroys memory power management in cases where that > is based on powering down entire memory banks. I don't think that per-bank CMA regions destroys memory power management more than the global CMA pool. Please note that the contiguous buffers (or in general dma-buffers) right now are unmovable so they don't fit well into memory power management. Best regards -- Marek Szyprowski Samsung Poland R&D Center -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Wed, 15 Jun 2011 10:36:18 +0200 Subject: [Linaro-mm-sig] [PATCH 08/10] mm: cma: Contiguous Memory Allocator added In-Reply-To: <201106142242.25157.arnd@arndb.de> References: <1307699698-29369-1-git-send-email-m.szyprowski@samsung.com> <20110614170158.GU2419@fooishbar.org> <201106142242.25157.arnd@arndb.de> Message-ID: <000901cc2b37$4c21f030$e465d090$%szyprowski@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hello, On Tuesday, June 14, 2011 10:42 PM Arnd Bergmann wrote: > On Tuesday 14 June 2011 20:58:25 Zach Pfeffer wrote: > > I've seen this split bank allocation in Qualcomm and TI SoCs, with > > Samsung, that makes 3 major SoC vendors (I would be surprised if > > Nvidia didn't also need to do this) - so I think some configurable > > method to control allocations is necessarily. The chips can't do > > decode without it (and by can't do I mean 1080P and higher decode is > > not functionally useful). Far from special, this would appear to be > > the default. > > Thanks for the insight, that's a much better argument than 'something > may need it'. Are those all chips without an IOMMU or do we also > need to solve the IOMMU case with split bank allocation? > > I think I'd still prefer to see the support for multiple regions split > out into one of the later patches, especially since that would defer > the question of how to do the initialization for this case and make > sure we first get a generic way. > > You've convinced me that we need to solve the problem of allocating > memory from a specific bank eventually, but separating it from the > one at hand (contiguous allocation) should help getting the important > groundwork in at first. > > The possible conflict that I still see with per-bank CMA regions are: > > * It completely destroys memory power management in cases where that > is based on powering down entire memory banks. I don't think that per-bank CMA regions destroys memory power management more than the global CMA pool. Please note that the contiguous buffers (or in general dma-buffers) right now are unmovable so they don't fit well into memory power management. Best regards -- Marek Szyprowski Samsung Poland R&D Center