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 2FE89C433E0 for ; Tue, 16 Feb 2021 08:49:59 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 9B75C64DF0 for ; Tue, 16 Feb 2021 08:49:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B75C64DF0 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 smtp3.osuosl.org (Postfix) with ESMTP id 2ED9F6F573 for ; Tue, 16 Feb 2021 08:49:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id L8B8ATGZjWtM for ; Tue, 16 Feb 2021 08:49:57 +0000 (UTC) Received: by smtp3.osuosl.org (Postfix, from userid 1001) id EDC6A6F51C; Tue, 16 Feb 2021 08:49:56 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTP id 788796ECA6; Tue, 16 Feb 2021 08:49:54 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4F55FC0174; Tue, 16 Feb 2021 08:49:54 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id DE42CC013A for ; Tue, 16 Feb 2021 08:49:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id C326E87031 for ; Tue, 16 Feb 2021 08:49:52 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id bkSr5t8sXCKZ for ; Tue, 16 Feb 2021 08:49:51 +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 hemlock.osuosl.org (Postfix) with ESMTPS id 3425E8701D for ; Tue, 16 Feb 2021 08:49:51 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 7CF7D6736F; Tue, 16 Feb 2021 09:49:47 +0100 (CET) Date: Tue, 16 Feb 2021 09:49:47 +0100 From: Christoph Hellwig To: Tomasz Figa Subject: Re: [PATCH 6/7] dma-iommu: implement ->alloc_noncontiguous Message-ID: <20210216084947.GA23897@lst.de> References: <20210202095110.1215346-1-hch@lst.de> <20210202095110.1215346-7-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Mauro Carvalho Chehab , Linux Media Mailing List , Linux Doc Mailing List , Linux Kernel Mailing List , "open list:IOMMU DRIVERS" , Ricardo Ribalda , Sergey Senozhatsky , Robin Murphy , Christoph Hellwig 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 Tue, Feb 16, 2021 at 05:14:55PM +0900, Tomasz Figa wrote: > When working on the videobuf2 integration with Sergey I noticed that > we always pass 0 as DMA attrs here, which removes the ability for > drivers to use DMA_ATTR_ALLOC_SINGLE_PAGES. > > It's quite important from a system stability point of view, because by > default the iommu_dma allocator would prefer big order allocations for > TLB locality reasons. For many devices, though, it doesn't really > affect the performance, because of random access patterns, so single > pages are good enough and reduce the risk of allocation failures or > latency due to fragmentation. > > Do you think we could add the attrs parameter to the > dma_alloc_noncontiguous() API? Yes, we could probably do that. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu