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 33BA3C3A589 for ; Thu, 15 Aug 2019 13:50:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 10A4A206C1 for ; Thu, 15 Aug 2019 13:50:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732576AbfHONu4 (ORCPT ); Thu, 15 Aug 2019 09:50:56 -0400 Received: from foss.arm.com ([217.140.110.172]:44456 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732426AbfHONu4 (ORCPT ); Thu, 15 Aug 2019 09:50:56 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 25C6D344; Thu, 15 Aug 2019 06:50:56 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 068C83F694; Thu, 15 Aug 2019 06:50:54 -0700 (PDT) Subject: Re: DMA-API: cacheline tracking ENOMEM, dma-debug disabled due to nouveau ? To: Christoph Hellwig , Corentin Labbe , bskeggs@redhat.com, airlied@linux.ie, m.szyprowski@samsung.com, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org References: <20190814145033.GA11190@Red> <20190814174927.GT7444@phenom.ffwll.local> <20190815133554.GE12036@lst.de> From: Robin Murphy Message-ID: Date: Thu, 15 Aug 2019 14:50:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190815133554.GE12036@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/08/2019 14:35, Christoph Hellwig wrote: > On Wed, Aug 14, 2019 at 07:49:27PM +0200, Daniel Vetter wrote: >> On Wed, Aug 14, 2019 at 04:50:33PM +0200, Corentin Labbe wrote: >>> Hello >>> >>> Since lot of release (at least since 4.19), I hit the following error message: >>> DMA-API: cacheline tracking ENOMEM, dma-debug disabled >>> >>> After hitting that, I try to check who is creating so many DMA mapping and see: >>> cat /sys/kernel/debug/dma-api/dump | cut -d' ' -f2 | sort | uniq -c >>> 6 ahci >>> 257 e1000e >>> 6 ehci-pci >>> 5891 nouveau >>> 24 uhci_hcd >>> >>> Does nouveau having this high number of DMA mapping is normal ? >> >> Yeah seems perfectly fine for a gpu. > > That is a lot and apparently overwhelm the dma-debug tracking. Robin > rewrote this code in Linux 4.21 to work a little better, so I'm curious > why this might have changes in 4.19, as dma-debug did not change at > all there. FWIW, the cacheline tracking entries are a separate thing from the dma-debug entries that I rejigged - judging by those numbers there should still be plenty of free dma-debug entries, but for some reason it has failed to extend the radix tree :/ Robin.