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=-1.4 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 21487C43381 for ; Tue, 19 Mar 2019 22:19:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E642C2175B for ; Tue, 19 Mar 2019 22:19:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727359AbfCSWTr (ORCPT ); Tue, 19 Mar 2019 18:19:47 -0400 Received: from mga11.intel.com ([192.55.52.93]:58372 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726686AbfCSWTr (ORCPT ); Tue, 19 Mar 2019 18:19:47 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Mar 2019 15:19:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,246,1549958400"; d="scan'208";a="308616822" Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga005.jf.intel.com with ESMTP; 19 Mar 2019 15:19:46 -0700 Date: Tue, 19 Mar 2019 07:18:26 -0700 From: Ira Weiny To: Dan Williams Cc: Jerome Glisse , Andrew Morton , Linux MM , Linux Kernel Mailing List , Felix Kuehling , Christian =?iso-8859-1?Q?K=F6nig?= , Ralph Campbell , John Hubbard , Jason Gunthorpe , Alex Deucher Subject: Re: [PATCH 00/10] HMM updates for 5.1 Message-ID: <20190319141826.GJ7485@iweiny-DESK2.sc.intel.com> References: <20190318170404.GA6786@redhat.com> <20190319094007.a47ce9222b5faacec3e96da4@linux-foundation.org> <20190319165802.GA3656@redhat.com> <20190319101249.d2076f4bacbef948055ae758@linux-foundation.org> <20190319171847.GC3656@redhat.com> <20190319174552.GA3769@redhat.com> <20190319190528.GA4012@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.1 (2018-12-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 19, 2019 at 12:13:40PM -0700, Dan Williams wrote: > On Tue, Mar 19, 2019 at 12:05 PM Jerome Glisse wrote: > > > > On Tue, Mar 19, 2019 at 11:42:00AM -0700, Dan Williams wrote: > > > On Tue, Mar 19, 2019 at 10:45 AM Jerome Glisse wrote: > > > > > > > > On Tue, Mar 19, 2019 at 10:33:57AM -0700, Dan Williams wrote: > > > > > On Tue, Mar 19, 2019 at 10:19 AM Jerome Glisse wrote: > > > > > > > > > > > > On Tue, Mar 19, 2019 at 10:12:49AM -0700, Andrew Morton wrote: > > > > > > > On Tue, 19 Mar 2019 12:58:02 -0400 Jerome Glisse wrote: [snip] > > > > Right now i am trying to unify driver for device that have can support > > the mmu notifier approach through HMM. Unify to a superset of driver > > that can not abide by mmu notifier is on my todo list like i said but > > it comes after. I do not want to make the big jump in just one go. So > > i doing thing under HMM and thus in HMM namespace, but once i tackle > > the larger set i will move to generic namespace what make sense. > > > > This exact approach did happen several time already in the kernel. In > > the GPU sub-system we did it several time. First do something for couple > > devices that are very similar then grow to a bigger set of devices and > > generalise along the way. > > > > So i do not see what is the problem of me repeating that same pattern > > here again. Do something for a smaller set before tackling it on for > > a bigger set. > > All of that is fine, but when I asked about the ultimate trajectory > that replaces hmm_range_dma_map() with an updated / HMM-aware GUP > implementation, the response was that hmm_range_dma_map() is here to > stay. The issue is not with forking off a small side effort, it's the > plan to absorb that capability into a common implementation across > non-HMM drivers where possible. Just to get on the record in this thread. +1 I think having an interface which handles the MMU notifier stuff for drivers is awesome but we need to agree that the trajectory is to help more drivers if possible. Ira