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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 4D159C43381 for ; Mon, 25 Feb 2019 16:51:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2723B20842 for ; Mon, 25 Feb 2019 16:51:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728565AbfBYQvL (ORCPT ); Mon, 25 Feb 2019 11:51:11 -0500 Received: from mga06.intel.com ([134.134.136.31]:4302 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728138AbfBYQvK (ORCPT ); Mon, 25 Feb 2019 11:51:10 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Feb 2019 08:51:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,411,1544515200"; d="scan'208";a="323239250" Received: from unknown (HELO localhost.localdomain) ([10.232.112.69]) by fmsmga005.fm.intel.com with ESMTP; 25 Feb 2019 08:51:08 -0800 Date: Mon, 25 Feb 2019 09:51:18 -0700 From: Keith Busch To: "Rafael J. Wysocki" Cc: Linux Kernel Mailing List , ACPI Devel Maling List , Linux Memory Management List , Linux API , Greg Kroah-Hartman , Dave Hansen , Dan Williams Subject: Re: [PATCHv6 07/10] acpi/hmat: Register processor domain to its memory Message-ID: <20190225165118.GK10237@localhost.localdomain> References: <20190214171017.9362-1-keith.busch@intel.com> <20190214171017.9362-8-keith.busch@intel.com> <20190222184831.GF10237@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 24, 2019 at 08:59:45PM +0100, Rafael J. Wysocki wrote: > On Fri, Feb 22, 2019 at 7:48 PM Keith Busch wrote: > > If I do it the other way around, that's going to make HMEM_REPORTING > > complicated if a non-ACPI implementation wants to report HMEM > > properties. > > But the mitigations that Dave was talking about get in the way, don't they? > > Say there is another Kconfig option,CACHE_MITIGATIONS, to enable them. > Then you want ACPI_HMAT to be set when that it set and you also want > ACPI_HMAT to be set when HMEM_REPORTING and ACPI_NUMA are both set. > > OTOH, you may not want HMEM_REPORTING to be set when CACHE_MITIGATIONS > is set, but that causes ACPI_HMAT to be set and which means that > ACPI_HMAT alone will not be sufficient to determine the > HMEM_REPORTING value. I can't think of when we'd want to suppress reporting these attributes to user space, but I can split HMAT enabling so it doesn't depend on HMEM_REPORTING just in case there really is an in-kernel user that definitely does not want the same attributes exported. > Now, if you prompt for HMEM_REPORTING and make it depend on ACPI_NUMA, > then ACPI_HMAT can be selected by that (regardless of the > CACHE_MITIGATIONS value). > > And if someone wants to use HMEM_REPORTING without ACPI_NUMA, it can > be made depend on whatever new option is there for that non-ACPI > mechanism. > > There might be a problem if someone wanted to enable the alternative > way of HMEM_REPORTING if ACPI_NUMA was set (in which case HMAT would > have to be ignored even if it was present), but in that case there > would need to be an explicit way to choose between HMAT and non-HMAT > anyway. > > In any case, I prefer providers to be selected by consumers and not > the other way around, in case there are multiple consumers for one > provider. Well, the HMEM_REPORTING fundamentally has no dependency on any of these things and I've put some effort into making this part provider agnostic. I will change it if this concern is gating acceptance, but I don't think it's as intuitive for generic interfaces to be the selector for implementation specific providers.