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 D09B0C433E0 for ; Fri, 19 Jun 2020 19:51:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8A9C20C09 for ; Fri, 19 Jun 2020 19:51:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="MMmRJ8t4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390739AbgFSTvr (ORCPT ); Fri, 19 Jun 2020 15:51:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44470 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390635AbgFSTvp (ORCPT ); Fri, 19 Jun 2020 15:51:45 -0400 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80570C0613EF for ; Fri, 19 Jun 2020 12:51:45 -0700 (PDT) Received: by mail-qk1-x744.google.com with SMTP id w1so10117255qkw.5 for ; Fri, 19 Jun 2020 12:51:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=zP3mPfj8fYVGpA7X3i9lQw/wDhwl6Nv+h6HgzhW86WQ=; b=MMmRJ8t4j4VSr9X/gdvrRhfckKKnEPttgsjRqD7r42N3dR4TTyyqhwnzRR2Zmqw9vU /eO8RZr/A4nHSOyE8HOfUMCXLr5V4yKzT96SAI89H9oM6ivtb11eu4o1b5IwFl/nQYDG BnpCLEibfwPpM+qQe2fTwD8TqkotDnif2MXx2+W5OqJhUu02J9GSkKwpu8Dh9btmlQsW HfPeSb4neRXQnhdWbAQBoeJfQU5yXw4BH7QCQBZFfTz7zBx/ENEemRvnCmMQHQcSOvEj 0arcTcBmJyDOK1t36aFed0to462HbPkMSNhWvaHJO5I28iu9xV3xW3atg8lfxqqFsEQb IKQg== 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:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=zP3mPfj8fYVGpA7X3i9lQw/wDhwl6Nv+h6HgzhW86WQ=; b=J6cnIzC+OppquRUF4gJ5c7ItZKjbjRb4zuiKkWvGRXsDSPvDdM99Nm+CiEZCZaH7v1 23ul0juHzYs/ijrtKTQaGPTC/S/BcaEkZO4ts4Nkuw6nBD6kK9FXUtKTg9N5eA0tbpgT uGKgWGOHJ/jAinKeLaZtOJG+dgjZ8INOFNddtmLXTGl42TUt57NL9AiB8kndRyf2pNQ7 TszmBc55dDHA3s9Zq5q+KbgfDFY9pH0bwNlX6kNlmCvN4+ndu5M8X/DGjNlFe9Zo60Ua VsgQRuxO6TDbCDj9hm5xdmP40H/9ohbBCgrfs6Ux4JbikdCKWRZUrC85DRoYYLgX0spa CZog== X-Gm-Message-State: AOAM533edfFJPlIlFHd/JlZ9VHz6V/tFrpukCCrATuESzOZYna3H0VrE PB2GatsgN3yr+ZDFNjTqtkVh88kmzCvM5Q== X-Google-Smtp-Source: ABdhPJyeNbiGf5pDE6/nVlB6izIza9irK+wIFfmkUW9Wq6/rfhl4M8xllFEi5LwJ5619wnq0QRE14Q== X-Received: by 2002:a37:b401:: with SMTP id d1mr5401845qkf.206.1592596304691; Fri, 19 Jun 2020 12:51:44 -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 a81sm7609057qkb.24.2020.06.19.12.51.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jun 2020 12:51:44 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.93) (envelope-from ) id 1jmN39-00B0gQ-Jd; Fri, 19 Jun 2020 16:51:43 -0300 Date: Fri, 19 Jun 2020 16:51:43 -0300 From: Jason Gunthorpe To: Felix Kuehling Cc: Alex Deucher , Jerome Glisse , linux-rdma , Thomas =?utf-8?B?SGVsbHN0csO2bSAoSW50ZWwp?= , Maarten Lankhorst , LKML , DRI Development , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Thomas Hellstrom , amd-gfx list , Daniel Vetter , Daniel Vetter , "open list:DMA BUFFER SHARING FRAMEWORK" , Intel Graphics Development , Christian =?utf-8?B?S8O2bmln?= , Mika Kuoppala Subject: Re: [Linaro-mm-sig] [PATCH 04/18] dma-fence: prime lockdep annotations Message-ID: <20200619195143.GS6578@ziepe.ca> References: <20200618172338.GM6578@ziepe.ca> <20200619113934.GN6578@ziepe.ca> <20200619151551.GP6578@ziepe.ca> <20200619172308.GQ6578@ziepe.ca> <20200619180935.GA10009@redhat.com> <86f7f5e5-81a0-5429-5a6e-0d3b0860cfae@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <86f7f5e5-81a0-5429-5a6e-0d3b0860cfae@amd.com> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Jun 19, 2020 at 03:30:32PM -0400, Felix Kuehling wrote: > We have a potential problem with CPU updating page tables while the GPU > is retrying on page table entries because 64 bit CPU transactions don't > arrive in device memory atomically. Except for 32 bit platforms atomicity is guarenteed if you use uncached writeq() to aligned addresses.. The linux driver model breaks of the writeX() stuff is not atomic. Jason