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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 3EAF0C433F5 for ; Fri, 31 Aug 2018 13:51:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4F4420837 for ; Fri, 31 Aug 2018 13:51:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E4F4420837 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727711AbeHaR7X (ORCPT ); Fri, 31 Aug 2018 13:59:23 -0400 Received: from mga04.intel.com ([192.55.52.120]:19895 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727344AbeHaR7X (ORCPT ); Fri, 31 Aug 2018 13:59:23 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Aug 2018 06:51:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,311,1531810800"; d="scan'208";a="69607600" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.157]) by orsmga008.jf.intel.com with SMTP; 31 Aug 2018 06:51:36 -0700 Received: by lahna (sSMTP sendmail emulation); Fri, 31 Aug 2018 16:51:35 +0300 Date: Fri, 31 Aug 2018 16:51:35 +0300 From: Mika Westerberg To: Jon Derrick Cc: Bjorn Helgaas , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Lorenzo Pieralisi , Keith Busch , Greg Kroah-Hartman , Sinan Kaya , Christoph Hellwig , Matthew Wilcox , Logan Gunthorpe , Stephen Bates Subject: Re: [PATCH v2] PCI: Equalize hotplug memory for non/occupied slots Message-ID: <20180831135135.GO2283@lahna.fi.intel.com> References: <1535667120-3002-1-git-send-email-jonathan.derrick@intel.com> <1535667120-3002-2-git-send-email-jonathan.derrick@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535667120-3002-2-git-send-email-jonathan.derrick@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 30, 2018 at 04:12:00PM -0600, Jon Derrick wrote: > Currently, a hotplug bridge will be given hpmemsize additional memory if > available, in order to satisfy any future hotplug allocation > requirements. > > These calculations don't consider the current memory size of the hotplug > bridge/slot, so hotplug bridges/slots which have downstream devices will > get their current allocation in addition to the hpmemsize value. > > This makes for possibly undesirable results with a mix of unoccupied and > occupied slots (ex, with hpmemsize=2M): > > 02:03.0 PCI bridge: <-- Occupied > Memory behind bridge: d6200000-d64fffff [size=3M] > 02:04.0 PCI bridge: <-- Unoccupied > Memory behind bridge: d6500000-d66fffff [size=2M] > > This change considers the current allocation size when using the > hpmemsize parameter to make the reservations predictable for the mix of > unoccupied and occupied slots: > > 02:03.0 PCI bridge: <-- Occupied > Memory behind bridge: d6200000-d63fffff [size=2M] > 02:04.0 PCI bridge: <-- Unoccupied > Memory behind bridge: d6400000-d65fffff [size=2M] > > The calculation for IO (hpiosize) should be similar, but platform > firmwares I've encountered (including QEMU) provide strict allocations > for IO and would not provide free IO resources for hotplug buses > in order to prove this calculation. > > Signed-off-by: Jon Derrick Reviewed-by: Mika Westerberg