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Mon, 9 Aug 2021 06:46:26 +0000 Received: from HQMAIL105.nvidia.com (172.20.187.12) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sun, 8 Aug 2021 23:46:25 -0700 Received: from [10.2.53.40] (172.20.187.5) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 9 Aug 2021 06:46:26 +0000 Subject: Re: [PATCH 1/3] mm/gup: documentation corrections for gup/pup To: Matthew Wilcox CC: Andrew Morton , LKML , References: <20210808235018.1924918-1-jhubbard@nvidia.com> <20210808235018.1924918-2-jhubbard@nvidia.com> From: John Hubbard Message-ID: Date: Sun, 8 Aug 2021 23:46:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.187.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL105.nvidia.com (172.20.187.12) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 695c84f3-dd83-4221-266f-08d95b016954 X-MS-TrafficTypeDiagnostic: CY4PR12MB1848: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:4714; 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X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Aug 2021 06:46:26.8194 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 695c84f3-dd83-4221-266f-08d95b016954 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.32];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BN8NAM11FT064.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR12MB1848 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/8/21 6:39 PM, Matthew Wilcox wrote: > On Sun, Aug 08, 2021 at 04:50:16PM -0700, John Hubbard wrote: >> @@ -103,8 +103,14 @@ static inline struct page *try_get_compound_head(struct page *page, int refs) >> * same time. (That's true throughout the get_user_pages*() and >> * pin_user_pages*() APIs.) Cases: >> * >> - * FOLL_GET: page's refcount will be incremented by 1. >> - * FOLL_PIN: page's refcount will be incremented by GUP_PIN_COUNTING_BIAS. >> + * FOLL_GET: page's refcount will be incremented by refs. > > I think this would read more clearly if it said @refs (throughout). OK, will change that for v2. > >> + * >> + * FOLL_PIN on compound pages that are > two pages long: page's refcount will >> + * be incremented by refs, and page[2].hpage_pinned_refcount will be >> + * incremented by refs * GUP_PIN_COUNTING_BIAS. >> + * >> + * FOLL_PIN on normal pages, or compound pages that are two pages long: >> + * page's refcount will be incremented by refs * GUP_PIN_COUNTING_BIAS. >> * >> * Return: head page (with refcount appropriately incremented) for success, or >> * NULL upon failure. If neither FOLL_GET nor FOLL_PIN was set, that's > > Did you run 'make htmldocs' and see how it renders? I haven't looked, > but this might work better as an rst list? > Hadn't occurred to me, due to my own incorrect mental separation between comment kernel docs, and rst formatting ("rst == Documentation/"). I'll give it a try. thanks, -- John Hubbard NVIDIA