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=-5.3 required=3.0 tests=BAYES_00, 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 F037BC433E0 for ; Mon, 1 Mar 2021 08:46:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9FC1464DF2 for ; Mon, 1 Mar 2021 08:46:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FC1464DF2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 378868D005D; Mon, 1 Mar 2021 03:46:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2FFBC8D0019; Mon, 1 Mar 2021 03:46:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1EFAD8D005D; Mon, 1 Mar 2021 03:46:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0127.hostedemail.com [216.40.44.127]) by kanga.kvack.org (Postfix) with ESMTP id 05B9C8D0019 for ; Mon, 1 Mar 2021 03:46:04 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C8430180ACF76 for ; Mon, 1 Mar 2021 08:46:03 +0000 (UTC) X-FDA: 77870673006.29.11568EE Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf14.hostedemail.com (Postfix) with ESMTP id F05BEC0007C8 for ; Mon, 1 Mar 2021 08:45:53 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id E262D68BEB; Mon, 1 Mar 2021 09:45:59 +0100 (CET) Date: Mon, 1 Mar 2021 09:45:59 +0100 From: Christoph Hellwig To: Christoph Hellwig , Andrew Morton , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Chris Wilson , Peter Zijlstra , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org Subject: Re: add remap_pfn_range_notrack instead of reinventing it in i915 Message-ID: <20210301084559.GA29133@lst.de> References: <20210301083320.943079-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: F05BEC0007C8 X-Stat-Signature: 5kwqkwimix1fcechao1txmrxnszrat6q Received-SPF: none (lst.de>: No applicable sender policy available) receiver=imf14; identity=mailfrom; envelope-from=""; helo=verein.lst.de; client-ip=213.95.11.211 X-HE-DKIM-Result: none/none X-HE-Tag: 1614588353-209457 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Mar 01, 2021 at 09:44:13AM +0100, Daniel Vetter wrote: > On Mon, Mar 01, 2021 at 09:33:18AM +0100, Christoph Hellwig wrote: > > Hi all, > > > > i915 has some reason to want to avoid the track_pfn_remap overhead in > > remap_pfn_range. Add a function to the core VM to do just that rather > > than reinventing the functionality poorly in the driver. > > It's not _notrack it's "rely on the tracking established by the struct > io_mapping". Exporting a _notrack version to drivers sounds like not > something we want to ever do. So I think you want a helper which takes the > io_mapping, and not something that encourages drivers to go full stupid. As far as I can tell there is no struct io_mapping anywhere near remap_io_sg.