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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65192CA0EC3 for ; Mon, 11 Sep 2023 21:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344043AbjIKVNH (ORCPT ); Mon, 11 Sep 2023 17:13:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243557AbjIKRTU (ORCPT ); Mon, 11 Sep 2023 13:19:20 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 177331AD for ; Mon, 11 Sep 2023 10:19:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1694452756; x=1725988756; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ovfcmpc5bfHVVimrVWvGkjkz+gms3X4ouh+AmvWcn/k=; b=cX8BnQb+E0jn18kqx2kvsQ+CR4zdfRRmAWxR/EBenJnZX4t6wc+5pTIh yx7wTuZ3JwQ78h44S3qz/A0dDRpp3mwSe6l7DIJykMIQFhNa46bafRTmL VZpc1jVMq0e7Yc4/YpaYIZA727aPeOFnNUfZTeCu9sfXAbIdxXlF+/iaS ki+teq1Xx0Mi3ztYZC/K8+AO3ABxpwiSfx0/HDDU+B5RHG9wjs+M+5CPt 5cuOxpvv0ZH7lgXqxQcUJkU1ERPKYMebWv61XR7E8Ma4AIHhy9J/kuoyQ mEec9p2Jp0X+KXX2MYli78G5E3LAvyj/kDPWUI9HmbHOqHwwfBwNunVvC g==; X-IronPort-AV: E=McAfee;i="6600,9927,10830"; a="358436284" X-IronPort-AV: E=Sophos;i="6.02,244,1688454000"; d="scan'208";a="358436284" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Sep 2023 10:19:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10830"; a="813472649" X-IronPort-AV: E=Sophos;i="6.02,244,1688454000"; d="scan'208";a="813472649" Received: from lbinmo2x-mobl1.gar.corp.intel.com (HELO [10.249.254.187]) ([10.249.254.187]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Sep 2023 10:19:12 -0700 Message-ID: <0a8799c3-1d4c-8d87-ebca-013f6541fbc4@linux.intel.com> Date: Mon, 11 Sep 2023 19:19:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH drm-misc-next v3 5/7] drm/gpuvm: add an abstraction for a VM / BO combination Content-Language: en-US To: Danilo Krummrich , airlied@gmail.com, daniel@ffwll.ch, matthew.brost@intel.com, sarah.walker@imgtec.com, donald.robson@imgtec.com, boris.brezillon@collabora.com, christian.koenig@amd.com, faith.ekstrand@collabora.com Cc: dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20230909153125.30032-1-dakr@redhat.com> <20230909153125.30032-6-dakr@redhat.com> From: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= In-Reply-To: <20230909153125.30032-6-dakr@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Danilo On 9/9/23 17:31, Danilo Krummrich wrote: > This patch adds an abstraction layer between the drm_gpuva mappings of > a particular drm_gem_object and this GEM object itself. The abstraction > represents a combination of a drm_gem_object and drm_gpuvm. The > drm_gem_object holds a list of drm_gpuvm_bo structures (the structure > representing this abstraction), while each drm_gpuvm_bo contains list of > mappings of this GEM object. > > This has multiple advantages: > > 1) We can use the drm_gpuvm_bo structure to attach it to various lists > of the drm_gpuvm. This is useful for tracking external and evicted > objects per VM, which is introduced in subsequent patches. > > 2) Finding mappings of a certain drm_gem_object mapped in a certain > drm_gpuvm becomes much cheaper. > > 3) Drivers can derive and extend the structure to easily represent > driver specific states of a BO for a certain GPUVM. > > The idea of this abstraction was taken from amdgpu, hence the credit for > this idea goes to the developers of amdgpu. > > Cc: Christian König > Signed-off-by: Danilo Krummrich Did you consider having the drivers embed the struct drm_gpuvm_bo in their own bo definition? I figure that would mean using the gem bo's refcounting and providing a helper to call from the driver's bo release. Looks like that could potentially save a lot of code? Or is there something that won't work with that approach? Thanks, Thomas