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[156.34.55.100]) by smtp.gmail.com with ESMTPSA id m10sm2903557qka.43.2019.08.16.09.31.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 16 Aug 2019 09:31:21 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1hyf8K-0007ns-SK; Fri, 16 Aug 2019 13:31:20 -0300 Date: Fri, 16 Aug 2019 13:31:20 -0300 From: Jason Gunthorpe To: Jan Kara Cc: Jerome Glisse , Vlastimil Babka , John Hubbard , Ira Weiny , Andrew Morton , Christoph Hellwig , Dan Williams , Dave Chinner , LKML , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [RFC PATCH 2/2] mm/gup: introduce vaddr_pin_pages_remote() Message-ID: <20190816163120.GF5398@ziepe.ca> References: <90e5cd11-fb34-6913-351b-a5cc6e24d85d@nvidia.com> <20190814234959.GA463@iweiny-DESK2.sc.intel.com> <2cbdf599-2226-99ae-b4d5-8909a0a1eadf@nvidia.com> <20190815132622.GG14313@quack2.suse.cz> <20190815133510.GA21302@quack2.suse.cz> <0d6797d8-1e04-1ebe-80a7-3d6895fe71b0@suse.cz> <20190816154404.GF3041@quack2.suse.cz> <20190816155220.GC3149@redhat.com> <20190816161355.GL3041@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190816161355.GL3041@quack2.suse.cz> User-Agent: Mutt/1.9.4 (2018-02-28) 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 Fri, Aug 16, 2019 at 06:13:55PM +0200, Jan Kara wrote: > > For 3 we do not need to take a reference at all :) So just forget about 3 > > it does not exist. For 3 the reference is the reference the CPU page table > > has on the page and that's it. GUP is no longer involve in ODP or anything > > like that. > > Yes, I understand. But the fact is that GUP calls are currently still there > e.g. in ODP code. If you can make the code work without taking a page > reference at all, I'm only happy :) We are working on it :) Jason