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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,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 4D7A8C43613 for ; Thu, 20 Jun 2019 13:47:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 225C92083B for ; Thu, 20 Jun 2019 13:47:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561038436; bh=d5ofdz+9QjwZAj1YbfVJI70wV21UwnW5CSJhDjRuEXc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gLtGNuQVt8zymwj9aUPgHwXyJ3p1QI7stNBZag+vyvG6bS53LiG7QHFZHiS/BiPqR HACDHSBofZIy6LtY8psLpVjAwZbza1xIXLxXUfZmnqmGOfTr8E/VJ3F1KNKiVQn6NH ahCG6Ro81m2b3/OCMvwyWMsGrpo8HOUmCozYf8gw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726697AbfFTNrP (ORCPT ); Thu, 20 Jun 2019 09:47:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:47768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726391AbfFTNrP (ORCPT ); Thu, 20 Jun 2019 09:47:15 -0400 Received: from localhost (173-25-83-245.client.mchsi.com [173.25.83.245]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id DA0B4206E0; Thu, 20 Jun 2019 13:47:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561038434; bh=d5ofdz+9QjwZAj1YbfVJI70wV21UwnW5CSJhDjRuEXc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FMcdIzXtTql+jmwRd9fsBmgATm1jxJS4XlsVljsVlhic8uNE6y2bzFIFUx6gVOFfO ynOCsn0X/MLyEZLUuHFX+AgI7mgipWHJXODK0CEQtFL4C+A5+MOo08518R8HwXH0XP uSM34PN5Bcjis2vD482kqy/Uz+ZobWlibEwEW9n0= Date: Thu, 20 Jun 2019 08:47:12 -0500 From: Bjorn Helgaas To: Logan Gunthorpe Cc: Nicholas Johnson , "benh@kernel.crashing.org" , "linux-pci@vger.kernel.org" Subject: Re: [nicholas.johnson-opensource@outlook.com.au: [PATCH v6 4/4] PCI: Add pci=hpmemprefsize parameter to set MMIO_PREF size independently] Message-ID: <20190620134712.GI143205@google.com> References: <89c6a6ee-46cc-4047-0093-30f07992e7e5@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <89c6a6ee-46cc-4047-0093-30f07992e7e5@deltatee.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jun 19, 2019 at 07:35:21PM -0600, Logan Gunthorpe wrote: > On 2019-06-19 6:56 p.m., Nicholas Johnson wrote: > > On Wed, Jun 19, 2019 at 10:45:38AM -0600, Logan Gunthorpe wrote: > >> On 2019-06-19 8:01 a.m., Nicholas Johnson wrote: > >>> ----- Forwarded message from Nicholas Johnson ----- > >>> > >>> Date: Thu, 23 May 2019 06:29:28 +0800 > >>> From: Nicholas Johnson > >>> To: linux-kernel@vger.kernel.org > >>> Cc: linux-pci@vger.kernel.org, bhelgaas@google.com, mika.westerberg@linux.intel.com, corbet@lwn.net, Nicholas Johnson > >>> Subject: [PATCH v6 4/4] PCI: Add pci=hpmemprefsize parameter to set MMIO_PREF size independently > >>> X-Mailer: git-send-email 2.19.1 > >>> > >>> Add kernel parameter pci=hpmemprefsize=nn[KMG] to control > >>> MMIO_PREF size for PCI hotplug bridges. > >> > >> Makes sense. > >> > >>> Change behaviour of pci=hpmemsize=nn[KMG] to not set MMIO_PREF > >>> size if hpmempref has been specified, rather than controlling > >>> both MMIO and MMIO_PREF sizes unconditionally. > >> > >> I don't think I like that fact that hpmemsize behaves differently > >> if hpmempref size is specfied before it. I'd probably suggest > >> having three parameters: hpmemsize which sets both as it always > >> has, a pref one and a regular one which each set one of > >> parameters. > > > > It does not matter if hpmempref is specified before or after > > hpmemsize. I made sure of that. > > > Originally, I proposed to depreciate hpiosize, hpmemsize, and > > introduce: hp_io_size, hp_mmio_size, hp_mmio_pref_size, each > > controlling its own window exclusively. > > > > The patch had the old parameters work with a warning, and if the > > new ones were specified, they would override the old ones. Then, > > after a few kernel releases, the old ones could be removed. > > Well I don't like that either. No need to depreciate hpmemsize. > > > Bjorn insisted that there be nil changes which break the existing > > parameters, and the solution he requested was to leave hpmemsize > > to work exactly the same (controlling both MMIO and MMIO_PREF), > > unless hpmemprefsize is given, which will take control of > > MMIO_PREF from hpmemsize. > > I agree with Bjorn here too but my suggestion is to leave hpmemsize > alone and have it set both values as it has always done. And add two > new parameters to set one or the other. Then there's none of this > "sets one if the other one wasn't set". Also, if I only want to > change the non-preftechable version then your method leaves no way > to do so without setting the preftechable version. Adding two new parameters sounds like a good idea to me.