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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 503BAC47409 for ; Thu, 19 Dec 2019 07:36:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 251532467B for ; Thu, 19 Dec 2019 07:36:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="rn2yGjgw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726622AbfLSHg3 (ORCPT ); Thu, 19 Dec 2019 02:36:29 -0500 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:4230 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726340AbfLSHg3 (ORCPT ); Thu, 19 Dec 2019 02:36:29 -0500 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 18 Dec 2019 23:36:17 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 18 Dec 2019 23:36:27 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 18 Dec 2019 23:36:27 -0800 Received: from [10.2.165.11] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 19 Dec 2019 07:36:25 +0000 Subject: Re: [PATCH v11 04/25] mm: devmap: refactor 1-based refcounting for ZONE_DEVICE pages To: Dan Williams CC: Andrew Morton , Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , Christoph Hellwig , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Ira Weiny , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman , Michal Hocko , Mike Kravetz , Paul Mackerras , Shuah Khan , Vlastimil Babka , , Maling list - DRI developers , KVM list , , Linux Doc Mailing List , linux-fsdevel , , "Linux-media@vger.kernel.org" , linux-rdma , linuxppc-dev , Netdev , Linux MM , LKML , Christoph Hellwig References: <20191216222537.491123-1-jhubbard@nvidia.com> <20191216222537.491123-5-jhubbard@nvidia.com>

From: John Hubbard X-Nvconfidentiality: public Message-ID: Date: Wed, 18 Dec 2019 23:33:36 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1576740978; bh=AwGIHszd33R/kLZlUt1Z4JwwlD2NSoQAiltNw2UIah0=; h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=rn2yGjgwQ9+/2v2mcxWjrZFxdrk3/eEgjxRU1LJiuOVyjVOa62J0tvoTcmLOK6fXS xTiiEKdaSrRaYvKoHJFISdC+5xDr9wuGKGy6eL+p8mnXTv3WmxTBQ5uSD1vNUHW7Zv FL1u5zml1dT0aGOGbVIB8FGZRe/vZmwx0E0SfZqPp5XPLjqF6k+D7FwuHs+yKnEljh 6K2DgflrDdhvNm7j657NcorkWkt+15POYkE/QPPC6A7qk9vcVVLh/jftFFqBiaLSef +CbFHF0Oi6KJR9YDOdsjceXX460BQcgisIE59hm4mMu6iV3pT5dz1gvUWjcugiRrZC tT/WLbmWB9r/w== Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 12/18/19 10:52 PM, Dan Williams wrote: > On Wed, Dec 18, 2019 at 9:51 PM John Hubbard wrote: >> >> On 12/18/19 9:27 PM, Dan Williams wrote: >> ... >>>> @@ -461,5 +449,5 @@ void __put_devmap_managed_page(struct page *page) >>>> page->mapping = NULL; >>>> page->pgmap->ops->page_free(page); >>>> } >>>> -EXPORT_SYMBOL(__put_devmap_managed_page); >>>> +EXPORT_SYMBOL(free_devmap_managed_page); >>> >>> This patch does not have a module consumer for >>> free_devmap_managed_page(), so the export should move to the patch >>> that needs the new export. >> >> Hi Dan, >> >> OK, I know that's a policy--although it seems quite pointless here given >> that this is definitely going to need an EXPORT. >> >> At the moment, the series doesn't use it in any module at all, so I'll just >> delete the EXPORT for now. >> >>> >>> Also the only reason that put_devmap_managed_page() is EXPORT_SYMBOL >>> instead of EXPORT_SYMBOL_GPL is that there was no practical way to >>> hide the devmap details from evey module in the kernel that did >>> put_page(). I would expect free_devmap_managed_page() to >>> EXPORT_SYMBOL_GPL if it is not inlined into an existing exported >>> static inline api. >>> >> >> Sure, I'll change it to EXPORT_SYMBOL_GPL when the time comes. We do have >> to be careful that we don't shut out normal put_page() types of callers, >> but...glancing through the current callers, that doesn't look to be a problem. >> Good. So it should be OK to do EXPORT_SYMBOL_GPL here. >> >> Are you *sure* you don't want to just pre-emptively EXPORT now, and save >> looking at it again? > > I'm positive. There is enough history for "trust me the consumer is > coming" turning out not to be true to justify the hassle in my mind. I > do trust you, but things happen. > OK, it's deleted locally. Thanks for looking at the patch. I'll post a v12 series that includes the change, once it looks like reviews are slowing down. thanks, -- John Hubbard NVIDIA