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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 19D24C76188 for ; Mon, 22 Jul 2019 12:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E193E20449 for ; Mon, 22 Jul 2019 12:01:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="UCILmwMh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730166AbfGVMBk (ORCPT ); Mon, 22 Jul 2019 08:01:40 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:48300 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729347AbfGVMBk (ORCPT ); Mon, 22 Jul 2019 08:01:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=9TwEeiv3tAVyHgkzTpEKGutIGiR1ezQhfTVqiOL+Sb0=; b=UCILmwMh4QosYLRTNnXrods3F 4KxY+e4JGnpRThW5geoeGaInPL7r1BXuS44bNjBBemcEa9ZgxZaHOE2oJQmNVQyO2WhH/943vstsT w20+k6OAS4AjohS8FWHKG3aBodnj/zud/jY8BKK+ZsOGilYtq7YvghVnKnCIfiHm5VEhxTvaeebFP 0PuKLNenX5rDBPcOmj5B95w47dd5BwlcWN+uAQCA7islpDVX4F2cG38rTkqdvx8vnhGBYz7dcui53 7hEJbp2L3mZ2cJomjlLAH6VT6ZV2c9rQYdIjQBGDvlxrMIbVARj5DueGfxUtGnE9XEs1E8yyeD9JU lsrmDoM5A==; Received: from hch by bombadil.infradead.org with local (Exim 4.92 #3 (Red Hat Linux)) id 1hpX0U-0005w8-Q0; Mon, 22 Jul 2019 12:01:30 +0000 Date: Mon, 22 Jul 2019 05:01:30 -0700 From: Christoph Hellwig To: Jason Gunthorpe Cc: John Hubbard , Pavel Machek , Christoph Hellwig , john.hubbard@gmail.com, SCheung@nvidia.com, akpm@linux-foundation.org, aneesh.kumar@linux.vnet.ibm.com, benh@kernel.crashing.org, bsingharora@gmail.com, dan.j.williams@intel.com, dnellans@nvidia.com, ebaskakov@nvidia.com, hannes@cmpxchg.org, jglisse@redhat.com, kirill.shutemov@linux.intel.com, linux-kernel@vger.kernel.org, liubo95@huawei.com, mhairgrove@nvidia.com, mhocko@kernel.org, paulmck@linux.vnet.ibm.com, ross.zwisler@linux.intel.com, sgutti@nvidia.com, torvalds@linux-foundation.org, vdavydov.dev@gmail.com Subject: Re: [PATCH] mm/Kconfig: additional help text for HMM_MIRROR option Message-ID: <20190722120130.GA17178@infradead.org> References: <20190717074124.GA21617@amd> <20190719013253.17642-1-jhubbard@nvidia.com> <20190719055748.GA29082@infradead.org> <20190719105239.GA10627@amd> <20190719114853.GB15816@ziepe.ca> <20190719120043.GA15320@infradead.org> <20190719120432.GC11224@amd> <20190722115804.GB7607@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722115804.GB7607@ziepe.ca> User-Agent: Mutt/1.11.4 (2019-03-13) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 22, 2019 at 08:58:04AM -0300, Jason Gunthorpe wrote: > No one has given me a satisfactory answer about the restriction > either. > > The only thing this kconfig controls that could possibly be arch > specific is the page walking code in hmm_range_snapshot and > related. > > Maybe there is/was some arch entanglement there? The page walking code is supposed to be platform independent. I did push a branch to the buildbot a few days ago to catch issues, and the only one found so far is an abuse of pte_index() that can be trivially fixed. The other thing I noticed is that the use of some of the p??_none/protnone/present checks seems inconsistent, but I did not have time to audit that yet.