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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 18173C41517 for ; Wed, 24 Jul 2019 13:57:03 +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 ECF9C21BF6 for ; Wed, 24 Jul 2019 13:57:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECF9C21BF6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de 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 BDDACE18; Wed, 24 Jul 2019 13:57:02 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 89FD6DC9 for ; Wed, 24 Jul 2019 13:57:01 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 644E4224 for ; Wed, 24 Jul 2019 13:57:00 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 4D0A368B20; Wed, 24 Jul 2019 15:56:57 +0200 (CEST) Date: Wed, 24 Jul 2019 15:56:57 +0200 From: Christoph Hellwig To: Catalin Marinas Subject: Re: [RFC 3/4] dma-direct: add dma_direct_min_mask Message-ID: <20190724135657.GA9075@lst.de> References: <20190717153135.15507-1-nsaenzjulienne@suse.de> <20190717153135.15507-4-nsaenzjulienne@suse.de> <20190718091526.GA25321@lst.de> <13dd1a4f33fcf814545f0d93f18429e853de9eaf.camel@suse.de> <58753252bd7964e3b9e9558b633bd325c4a898a1.camel@suse.de> <20190724135124.GA44864@arrakis.emea.arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190724135124.GA44864@arrakis.emea.arm.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: stefan.wahren@i2se.com, f.fainelli@gmail.com, Robin Murphy , phil@raspberrypi.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jisheng.Zhang@synaptics.com, mbrugger@suse.com, Nicolas Saenz Julienne , will@kernel.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.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 On Wed, Jul 24, 2019 at 02:51:24PM +0100, Catalin Marinas wrote: > I think it may be better if we have both ZONE_DMA and ZONE_DMA32 on > arm64. ZONE_DMA would be based on the smallest dma-ranges as described > in the DT while DMA32 covers the first naturally aligned 4GB of RAM > (unchanged). When a smaller ZONE_DMA is not needed, it could be expanded > to cover what would normally be ZONE_DMA32 (or could we have ZONE_DMA as > 0-bytes? I don't think GFP_DMA can still allocate memory in this case). > > We'd probably have to define ARCH_ZONE_DMA_BITS for arm64 to something > smaller than 32-bit but sufficient to cover the known platforms like > RPi4 (the current 24 is too small, so maybe 30). AFAICT, > __dma_direct_optimal_gfp_mask() figures out whether GFP_DMA or GFP_DMA32 > should be passed. ARCH_ZONE_DMA_BITS should probably become a variable. That way we can just initialize it to the default 24 bits in kernel/dma/direct.c and allow architectures to override it in their early boot code. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu