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=-5.3 required=3.0 tests=BAYES_00, 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 36FF8C4727E for ; Sat, 26 Sep 2020 14:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F3312184D for ; Sat, 26 Sep 2020 14:14:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729356AbgIZOOh (ORCPT ); Sat, 26 Sep 2020 10:14:37 -0400 Received: from verein.lst.de ([213.95.11.211]:59292 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726210AbgIZOOh (ORCPT ); Sat, 26 Sep 2020 10:14:37 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 6B5EE68B05; Sat, 26 Sep 2020 16:14:29 +0200 (CEST) Date: Sat, 26 Sep 2020 16:14:28 +0200 From: Christoph Hellwig To: Tomasz Figa Cc: Christoph Hellwig , Mauro Carvalho Chehab , Thomas Bogendoerfer , "James E.J. Bottomley" , Joonyoung Shim , Seung-Woo Kim , Ben Skeggs , Marek Szyprowski , Matt Porter , iommu@lists.linux-foundation.org, Stefan Richter , linux1394-devel@lists.sourceforge.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-samsung-soc@vger.kernel.org, nouveau@lists.freedesktop.org, netdev@vger.kernel.org, linux-scsi@vger.kernel.org, linux-mm@kvack.org, alsa-devel@alsa-project.org Subject: Re: [PATCH 17/18] dma-iommu: implement ->alloc_noncoherent Message-ID: <20200926141428.GB10379@lst.de> References: <20200915155122.1768241-1-hch@lst.de> <20200915155122.1768241-18-hch@lst.de> <20200925184622.GB3607091@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200925184622.GB3607091@chromium.org> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Fri, Sep 25, 2020 at 06:46:22PM +0000, Tomasz Figa wrote: > > +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, > > + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) > > +{ > > + if (!gfpflags_allow_blocking(gfp)) { > > + struct page *page; > > + > > + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); > > + if (!page) > > + return NULL; > > + return page_address(page); > > + } > > + > > + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, > > + PAGE_KERNEL, 0); > > iommu_dma_alloc_remap() makes use of the DMA_ATTR_ALLOC_SINGLE_PAGES attribute > to optimize the allocations for devices which don't care about how contiguous > the backing memory is. Do you think we could add an attrs argument to this > function and pass it there? > > As ARM is being moved to the common iommu-dma layer as well, we'll probably > make use of the argument to support the DMA_ATTR_NO_KERNEL_MAPPING attribute to > conserve the vmalloc area. We could probably at it. However I wonder why this is something the drivers should care about. Isn't this really something that should be a kernel-wide policy for a given system? 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=-5.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_NONE,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 F1476C2D0A8 for ; Sat, 26 Sep 2020 14:15:33 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (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 6CF302075A for ; Sat, 26 Sep 2020 14:15:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="tYopDxeO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6CF302075A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 723A71944; Sat, 26 Sep 2020 16:14:40 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 723A71944 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1601129730; bh=m/pWUM2bMReEv8jncKYWTiA7rHF48rneBW1KwjAdpvo=; h=Date:From:To:Subject:References:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=tYopDxeOyvhEx0BxoawCx87O+OWSpx4XhwzKpE9TtLkdEXvkpOs2sRJOvtMBv7SJb nfRhfPFFkXI4tglBHrPzhyhjVjjOyv8Lk9QRY+Gtd+D/D8lxLidgESgtN80K/HD9+F IjOYjMXshM00pjQkibgwXFM/slkINQ04qucoBzAs= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 055DDF80229; Sat, 26 Sep 2020 16:14:40 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 2C9E2F80232; Sat, 26 Sep 2020 16:14:38 +0200 (CEST) Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id BD76BF800FD for ; Sat, 26 Sep 2020 16:14:32 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz BD76BF800FD Received: by verein.lst.de (Postfix, from userid 2407) id 6B5EE68B05; Sat, 26 Sep 2020 16:14:29 +0200 (CEST) Date: Sat, 26 Sep 2020 16:14:28 +0200 From: Christoph Hellwig To: Tomasz Figa Subject: Re: [PATCH 17/18] dma-iommu: implement ->alloc_noncoherent Message-ID: <20200926141428.GB10379@lst.de> References: <20200915155122.1768241-1-hch@lst.de> <20200915155122.1768241-18-hch@lst.de> <20200925184622.GB3607091@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200925184622.GB3607091@chromium.org> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: alsa-devel@alsa-project.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, linux1394-devel@lists.sourceforge.net, Christoph Hellwig , Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, Thomas Bogendoerfer , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Stefan Richter X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Fri, Sep 25, 2020 at 06:46:22PM +0000, Tomasz Figa wrote: > > +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, > > + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) > > +{ > > + if (!gfpflags_allow_blocking(gfp)) { > > + struct page *page; > > + > > + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); > > + if (!page) > > + return NULL; > > + return page_address(page); > > + } > > + > > + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, > > + PAGE_KERNEL, 0); > > iommu_dma_alloc_remap() makes use of the DMA_ATTR_ALLOC_SINGLE_PAGES attribute > to optimize the allocations for devices which don't care about how contiguous > the backing memory is. Do you think we could add an attrs argument to this > function and pass it there? > > As ARM is being moved to the common iommu-dma layer as well, we'll probably > make use of the argument to support the DMA_ATTR_NO_KERNEL_MAPPING attribute to > conserve the vmalloc area. We could probably at it. However I wonder why this is something the drivers should care about. Isn't this really something that should be a kernel-wide policy for a given system? From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 17/18] dma-iommu: implement ->alloc_noncoherent Date: Sat, 26 Sep 2020 16:14:28 +0200 Message-ID: <20200926141428.GB10379@lst.de> References: <20200915155122.1768241-1-hch@lst.de> <20200915155122.1768241-18-hch@lst.de> <20200925184622.GB3607091@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20200925184622.GB3607091@chromium.org> To: Tomasz Figa Cc: Christoph Hellwig , Mauro Carvalho Chehab , Thomas Bogendoerfer , "James E.J. Bottomley" , Joonyoung Shim , Seung-Woo Kim , Ben Skeggs , Marek Szyprowski , Matt Porter , iommu@lists.linux-foundation.org, Stefan Richter , linux1394-devel@lists.sourceforge.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-samsung-soc@vger.kernel.org, nouveau@lists.freedesktop.org, netdev@vger.kernel. List-Id: nouveau.vger.kernel.org On Fri, Sep 25, 2020 at 06:46:22PM +0000, Tomasz Figa wrote: > > +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, > > + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) > > +{ > > + if (!gfpflags_allow_blocking(gfp)) { > > + struct page *page; > > + > > + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); > > + if (!page) > > + return NULL; > > + return page_address(page); > > + } > > + > > + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, > > + PAGE_KERNEL, 0); > > iommu_dma_alloc_remap() makes use of the DMA_ATTR_ALLOC_SINGLE_PAGES attribute > to optimize the allocations for devices which don't care about how contiguous > the backing memory is. Do you think we could add an attrs argument to this > function and pass it there? > > As ARM is being moved to the common iommu-dma layer as well, we'll probably > make use of the argument to support the DMA_ATTR_NO_KERNEL_MAPPING attribute to > conserve the vmalloc area. We could probably at it. However I wonder why this is something the drivers should care about. Isn't this really something that should be a kernel-wide policy for a given system? 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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 AF504C2D0A8 for ; Sat, 26 Sep 2020 14:14:41 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 33A4D2168B for ; Sat, 26 Sep 2020 14:14:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33A4D2168B 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 localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id DFBB68693F; Sat, 26 Sep 2020 14:14:40 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cfGw2yS4mWwv; Sat, 26 Sep 2020 14:14:40 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 066E3868B5; Sat, 26 Sep 2020 14:14:40 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id DE235C0859; Sat, 26 Sep 2020 14:14:39 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 605C5C0051 for ; Sat, 26 Sep 2020 14:14:38 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 46FBF2037B for ; Sat, 26 Sep 2020 14:14:38 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id yHauDbbpDEmU for ; Sat, 26 Sep 2020 14:14:36 +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 silver.osuosl.org (Postfix) with ESMTPS id B2CAF203B2 for ; Sat, 26 Sep 2020 14:14:36 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 6B5EE68B05; Sat, 26 Sep 2020 16:14:29 +0200 (CEST) Date: Sat, 26 Sep 2020 16:14:28 +0200 From: Christoph Hellwig To: Tomasz Figa Subject: Re: [PATCH 17/18] dma-iommu: implement ->alloc_noncoherent Message-ID: <20200926141428.GB10379@lst.de> References: <20200915155122.1768241-1-hch@lst.de> <20200915155122.1768241-18-hch@lst.de> <20200925184622.GB3607091@chromium.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200925184622.GB3607091@chromium.org> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: alsa-devel@alsa-project.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, linux1394-devel@lists.sourceforge.net, Christoph Hellwig , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, Thomas Bogendoerfer , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Stefan Richter X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Fri, Sep 25, 2020 at 06:46:22PM +0000, Tomasz Figa wrote: > > +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, > > + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) > > +{ > > + if (!gfpflags_allow_blocking(gfp)) { > > + struct page *page; > > + > > + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); > > + if (!page) > > + return NULL; > > + return page_address(page); > > + } > > + > > + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, > > + PAGE_KERNEL, 0); > > iommu_dma_alloc_remap() makes use of the DMA_ATTR_ALLOC_SINGLE_PAGES attribute > to optimize the allocations for devices which don't care about how contiguous > the backing memory is. Do you think we could add an attrs argument to this > function and pass it there? > > As ARM is being moved to the common iommu-dma layer as well, we'll probably > make use of the argument to support the DMA_ATTR_NO_KERNEL_MAPPING attribute to > conserve the vmalloc area. We could probably at it. However I wonder why this is something the drivers should care about. Isn't this really something that should be a kernel-wide policy for a given system? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-6.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 8D12AC2D0A8 for ; Sat, 26 Sep 2020 14:16:27 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 1173B208A9 for ; Sat, 26 Sep 2020 14:16:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="IOKPyf2c" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1173B208A9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XdBIUBKT6TO5s5wLIqAjrttJU3/LMRERMG0PI7ZShfc=; b=IOKPyf2c9Ry3LzRmsAYCTh0Jx 57K2nmB+Q/V6/nheE8dj0hvAu8r6M3KDPZ0oDXeouAys83Is9wLgYMAxX3ZvDt9KzBmvRvxMJ9KCg PSII5IDP7mq9mnCv5o+0klkO6CFRh4VlqWYneAfQCo2uYxGbJpchweDtfnd0ojOLmRzEd+YuHXj5M J5nvTHLkpKoNOYx7GyMxbr9omynrWOd3unGg8TF/02L2amylkcR/0x5rjOcIFl0Pg9i5izOjDfyMr +bNFM78vLRejSyU3kPZ8yK7jAviDUXwu1TNsR4SZw0B9gLEfLoDVXDCymzJhRLr98SGw+aDAE9O0k Ku8YlxbaQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kMAyC-0000VF-Tm; Sat, 26 Sep 2020 14:14:36 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kMAyB-0000Up-7c for linux-arm-kernel@lists.infradead.org; Sat, 26 Sep 2020 14:14:36 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 6B5EE68B05; Sat, 26 Sep 2020 16:14:29 +0200 (CEST) Date: Sat, 26 Sep 2020 16:14:28 +0200 From: Christoph Hellwig To: Tomasz Figa Subject: Re: [PATCH 17/18] dma-iommu: implement ->alloc_noncoherent Message-ID: <20200926141428.GB10379@lst.de> References: <20200915155122.1768241-1-hch@lst.de> <20200915155122.1768241-18-hch@lst.de> <20200925184622.GB3607091@chromium.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200925184622.GB3607091@chromium.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200926_101435_396064_1B99AE13 X-CRM114-Status: GOOD ( 16.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alsa-devel@alsa-project.org, linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, linux1394-devel@lists.sourceforge.net, Christoph Hellwig , Marek Szyprowski , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , linux-scsi@vger.kernel.org, Ben Skeggs , Matt Porter , linux-media@vger.kernel.org, Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, Thomas Bogendoerfer , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Stefan Richter Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Sep 25, 2020 at 06:46:22PM +0000, Tomasz Figa wrote: > > +static void *iommu_dma_alloc_noncoherent(struct device *dev, size_t size, > > + dma_addr_t *handle, enum dma_data_direction dir, gfp_t gfp) > > +{ > > + if (!gfpflags_allow_blocking(gfp)) { > > + struct page *page; > > + > > + page = dma_common_alloc_pages(dev, size, handle, dir, gfp); > > + if (!page) > > + return NULL; > > + return page_address(page); > > + } > > + > > + return iommu_dma_alloc_remap(dev, size, handle, gfp | __GFP_ZERO, > > + PAGE_KERNEL, 0); > > iommu_dma_alloc_remap() makes use of the DMA_ATTR_ALLOC_SINGLE_PAGES attribute > to optimize the allocations for devices which don't care about how contiguous > the backing memory is. Do you think we could add an attrs argument to this > function and pass it there? > > As ARM is being moved to the common iommu-dma layer as well, we'll probably > make use of the argument to support the DMA_ATTR_NO_KERNEL_MAPPING attribute to > conserve the vmalloc area. We could probably at it. However I wonder why this is something the drivers should care about. Isn't this really something that should be a kernel-wide policy for a given system? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel