From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Hubbard Subject: Re: [PATCH 2/2] mm: set PG_dma_pinned on get_user_pages*() Date: Mon, 18 Jun 2018 10:50:57 -0700 Message-ID: References: <20180617012510.20139-1-jhubbard@nvidia.com> <20180617012510.20139-3-jhubbard@nvidia.com> <20180617200432.krw36wrcwidb25cj@ziepe.ca> <311eba48-60f1-b6cc-d001-5cc3ed4d76a9@nvidia.com> <20180618081258.GB16991@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180618081258.GB16991@lst.de> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Christoph Hellwig Cc: Dan Williams , Jason Gunthorpe , john.hubbard@gmail.com, Matthew Wilcox , Michal Hocko , Christopher Lameter , Jan Kara , Linux MM , LKML , linux-rdma List-Id: linux-rdma@vger.kernel.org On 06/18/2018 01:12 AM, Christoph Hellwig wrote: > On Sun, Jun 17, 2018 at 01:28:18PM -0700, John Hubbard wrote: >> Yes. However, my thinking was: get_user_pages() can become a way to indicate that >> these pages are going to be treated specially. In particular, the caller >> does not really want or need to support certain file operations, while the >> page is flagged this way. >> >> If necessary, we could add a new API call. > > That API call is called get_user_pages_longterm. OK...I had the impression that this was just semi-temporary API for dax, but given that it's an exported symbol, I guess it really is here to stay. Anyway, are you thinking that we could set the new page flag here? Or just pointing out that the other get_user_pages* variants are the wrong place?