From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0584C31E4B for ; Fri, 14 Jun 2019 14:17:03 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BCA5621537 for ; Fri, 14 Jun 2019 14:17:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BCA5621537 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 94C80117E; Fri, 14 Jun 2019 14:17:03 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 16FE31153 for ; Fri, 14 Jun 2019 14:17:03 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [207.82.80.151]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 473EBE5 for ; Fri, 14 Jun 2019 14:17:02 +0000 (UTC) Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-171-6ZL5OlDfPHWG6RvRpXiEQg-1; Fri, 14 Jun 2019 15:15:45 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 14 Jun 2019 15:15:44 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 14 Jun 2019 15:15:44 +0100 From: David Laight To: 'Christoph Hellwig' , Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Daniel Vetter , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , "Ian Abbott" , H Hartley Sweeten Subject: RE: [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous Thread-Topic: [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous Thread-Index: AQHVIrfpTFjppS25RkWUhwqPPyqZ4qabLzdw Date: Fri, 14 Jun 2019 14:15:44 +0000 Message-ID: References: <20190614134726.3827-1-hch@lst.de> <20190614134726.3827-17-hch@lst.de> In-Reply-To: <20190614134726.3827-17-hch@lst.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: 6ZL5OlDfPHWG6RvRpXiEQg-1 X-Mimecast-Spam-Score: 0 Cc: "devel@driverdev.osuosl.org" , "linux-s390@vger.kernel.org" , Intel Linux Wireless , "linux-rdma@vger.kernel.org" , "netdev@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , "linux-wireless@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-mm@kvack.org" , "iommu@lists.linux-foundation.org" , "moderated list:ARM PORT" , "linux-media@vger.kernel.org" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org From: Christoph Hellwig > Sent: 14 June 2019 14:47 > > Many architectures (e.g. arm, m68 and sh) have always used exact > allocation in their dma coherent allocator, which avoids a lot of > memory waste especially for larger allocations. Lift this behavior > into the generic allocator so that dma-direct and the generic IOMMU > code benefit from this behavior as well. > > Signed-off-by: Christoph Hellwig > --- > include/linux/dma-contiguous.h | 8 +++++--- > kernel/dma/contiguous.c | 17 +++++++++++------ > 2 files changed, 16 insertions(+), 9 deletions(-) > > diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h > index c05d4e661489..2e542e314acf 100644 > --- a/include/linux/dma-contiguous.h > +++ b/include/linux/dma-contiguous.h > @@ -161,15 +161,17 @@ static inline struct page *dma_alloc_contiguous(struct device *dev, size_t size, > gfp_t gfp) > { > int node = dev ? dev_to_node(dev) : NUMA_NO_NODE; > - size_t align = get_order(PAGE_ALIGN(size)); > + void *cpu_addr = alloc_pages_exact_node(node, size, gfp); > > - return alloc_pages_node(node, gfp, align); > + if (!cpu_addr) > + return NULL; > + return virt_to_page(p); > } Does this still guarantee that requests for 16k will not cross a 16k boundary? It looks like you are losing the alignment parameter. There may be drivers and hardware that also require 12k allocates to not cross 16k boundaries (etc). David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu