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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 42B97C433EF for ; Thu, 25 Nov 2021 06:12:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A89586B0074; Thu, 25 Nov 2021 01:11:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A38886B0075; Thu, 25 Nov 2021 01:11:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 926DD6B007B; Thu, 25 Nov 2021 01:11:46 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id 819A16B0074 for ; Thu, 25 Nov 2021 01:11:46 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 3EA3A18540B8A for ; Thu, 25 Nov 2021 06:11:36 +0000 (UTC) X-FDA: 78846430992.22.D76B86C Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf06.hostedemail.com (Postfix) with ESMTP id 58B78801AB08 for ; Thu, 25 Nov 2021 06:11:34 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 0B8A268B05; Thu, 25 Nov 2021 07:11:31 +0100 (CET) Date: Thu, 25 Nov 2021 07:11:30 +0100 From: Christoph Hellwig To: Joao Martins Cc: linux-mm@kvack.org, Dan Williams , Vishal Verma , Dave Jiang , Naoya Horiguchi , Matthew Wilcox , Jason Gunthorpe , John Hubbard , Jane Chu , Muchun Song , Mike Kravetz , Andrew Morton , Jonathan Corbet , Christoph Hellwig , nvdimm@lists.linux.dev, linux-doc@vger.kernel.org Subject: Re: [PATCH v6 04/10] mm/memremap: add ZONE_DEVICE support for compound pages Message-ID: <20211125061130.GA682@lst.de> References: <20211124191005.20783-1-joao.m.martins@oracle.com> <20211124191005.20783-5-joao.m.martins@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211124191005.20783-5-joao.m.martins@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 58B78801AB08 X-Stat-Signature: fhks3qn3en4k3m3sr5pc3usqsekshhiz Authentication-Results: imf06.hostedemail.com; dkim=none; spf=none (imf06.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-HE-Tag: 1637820694-895100 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Nov 24, 2021 at 07:09:59PM +0000, Joao Martins wrote: > Add a new @vmemmap_shift property for struct dev_pagemap which specifies that a > devmap is composed of a set of compound pages of order @vmemmap_shift, instead of > base pages. When a compound page devmap is requested, all but the first > page are initialised as tail pages instead of order-0 pages. Please wrap commit log lines after 73 characters. > #define for_each_device_pfn(pfn, map, i) \ > - for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(pfn)) > + for (pfn = pfn_first(map, i); pfn < pfn_end(map, i); pfn = pfn_next(map, pfn)) It would be nice to fix up this long line while you're at it. > static void dev_pagemap_kill(struct dev_pagemap *pgmap) > { > @@ -315,8 +315,8 @@ static int pagemap_range(struct dev_pagemap *pgmap, struct mhp_params *params, > memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], > PHYS_PFN(range->start), > PHYS_PFN(range_len(range)), pgmap); > - percpu_ref_get_many(pgmap->ref, pfn_end(pgmap, range_id) > - - pfn_first(pgmap, range_id)); > + percpu_ref_get_many(pgmap->ref, (pfn_end(pgmap, range_id) > + - pfn_first(pgmap, range_id)) >> pgmap->vmemmap_shift); In the Linux coding style the - goes ointo the first line. But it would be really nice to clean this up with a helper ala pfn_len anyway: percpu_ref_get_many(pgmap->ref, pfn_len(pgmap, range_id) >> pgmap->vmemmap_shift);