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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 13737C433DF for ; Tue, 16 Jun 2020 14:53:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E68AD20679 for ; Tue, 16 Jun 2020 14:53:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="cDN3DzBN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729053AbgFPOxP (ORCPT ); Tue, 16 Jun 2020 10:53:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727804AbgFPOxO (ORCPT ); Tue, 16 Jun 2020 10:53:14 -0400 Received: from mail-qv1-xf43.google.com (mail-qv1-xf43.google.com [IPv6:2607:f8b0:4864:20::f43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CAF0C061573 for ; Tue, 16 Jun 2020 07:53:14 -0700 (PDT) Received: by mail-qv1-xf43.google.com with SMTP id e2so9591074qvw.7 for ; Tue, 16 Jun 2020 07:53:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=H9Q21GJcnralnv81ky+DYZCuyhzGkXe+xlvLrhcRUVI=; b=cDN3DzBNq5d3CrdALYsiOTFh73YRcI8lQ7uTSznJPv8dAJPnHjJPQR57lcTVwcL/Fu tV3NTbV5GNoBVgT5Y9FK7M+PwBjksAzlKvZZnxf+Qkd/PqTbrIdNSIbQI4xY6GgG5IkN 2i29pdJFycDxjY2QVTv0QiEB95VIbTnGIGt0UTkJ1Csd3R+WgZXFN5sle6nrM8u0InPD 03ylAeGN5+aJZmvaChOTyf6V/AGcN+wyw9nUErW3py9ORSzNIR2Kd+m+VbjIZ7U5Y8CF +bk0T6Aw1wPbeMExKzclzBgPz36VephSSjSjX1HFVeLmX9lSoGuhN4yVL+U6sHPpHMa8 lzug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=H9Q21GJcnralnv81ky+DYZCuyhzGkXe+xlvLrhcRUVI=; b=iyx4/rZ1ZG7576B5RMbDo2Nml2JRxkR0hZDvNrpRkcNvA1hl570giZuPStORqus6v3 7dvogefcKfpm1A4fib15Wht/ye474K7mpMlwfYpWpkPmPyvvXoXREtYfj3TlAF9eFRBt sU7hxL/aNPYCbwUMuEbzVDB7rRtaM3nWhww5WP43p2YNCUn/ehkXOLuR+HGg16dmEI/K Q6tum1Tgn4EBhhgyVi9ZPxvMcL+CNCbKi3oXgDLNr3YrxF/JPLyzOyB82Ita9e410ndu D7Z/ULRfcgzuZW0Hz/AkDssZbX54F9NOHMAh4WAipUTs45/DzkRtWceaPYTiST1/+c2Y 3lqA== X-Gm-Message-State: AOAM5313hbpnQ34MrTW4ZnQQaOJAiQXTiI67mKrNJ9NIBD0yZvGhk9Kv /AJ8yczXzb8hRozKgRG5YF9cOg== X-Google-Smtp-Source: ABdhPJzP5DGSQb5Sh+luEoCiwZvsmX+7FP3MYwRCXpBsltvvGKDh3l1qc0mmf+FYXhbSQFkMBoXxZQ== X-Received: by 2002:a0c:e9cd:: with SMTP id q13mr2731630qvo.23.1592319193724; Tue, 16 Jun 2020 07:53:13 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-156-34-48-30.dhcp-dynamic.fibreop.ns.bellaliant.net. [156.34.48.30]) by smtp.gmail.com with ESMTPSA id g9sm14433034qtq.66.2020.06.16.07.53.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 16 Jun 2020 07:53:13 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.93) (envelope-from ) id 1jlCxc-0096j7-MB; Tue, 16 Jun 2020 11:53:12 -0300 Date: Tue, 16 Jun 2020 11:53:12 -0300 From: Jason Gunthorpe To: Thomas =?utf-8?B?SGVsbHN0csO2bSAoSW50ZWwp?= , DRI Development , linux-rdma@vger.kernel.org, Intel Graphics Development , Maarten Lankhorst , LKML , amd-gfx@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Thomas Hellstrom , Daniel Vetter , linux-media@vger.kernel.org, Christian =?utf-8?B?S8O2bmln?= , Mika Kuoppala Subject: Re: [Linaro-mm-sig] [PATCH 04/18] dma-fence: prime lockdep annotations Message-ID: <20200616145312.GC6578@ziepe.ca> References: <20200604081224.863494-1-daniel.vetter@ffwll.ch> <20200604081224.863494-5-daniel.vetter@ffwll.ch> <20200611083430.GD20149@phenom.ffwll.local> <20200611141515.GW6578@ziepe.ca> <20200616120719.GL20149@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200616120719.GL20149@phenom.ffwll.local> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Jun 16, 2020 at 02:07:19PM +0200, Daniel Vetter wrote: > > > I've pinged a bunch of armsoc gpu driver people and ask them how much this > > > hurts, so that we have a clear answer. On x86 I don't think we have much > > > of a choice on this, with userptr in amd and i915 and hmm work in nouveau > > > (but nouveau I think doesn't use dma_fence in there). > > > > Right, nor will RDMA ODP. > > Hm, what's the context here? I thought RDMA side you really don't want > dma_fence in mmu_notifiers, so not clear to me what you're agreeing on > here. rdma does not use dma_fence at all, and though it is hard to tell, I didn't notice a dma_fence in the nouveau invalidation call path. At the very least I think there should be some big warning that dma_fence in notifiers should be avoided. Ie it is strange that the new totally-not-a-gpu drivers use dma_fence, they surely don't have the same constraints as the existing GPU world, and it would be annoying to see dma_fence notifiers spring up in them Jason