From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f69.google.com (mail-pg0-f69.google.com [74.125.83.69]) by kanga.kvack.org (Postfix) with ESMTP id D69CA6B0005 for ; Thu, 25 Jan 2018 11:47:29 -0500 (EST) Received: by mail-pg0-f69.google.com with SMTP id i1so5057403pgv.22 for ; Thu, 25 Jan 2018 08:47:29 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id p184si4832110pfg.371.2018.01.25.08.47.27 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 25 Jan 2018 08:47:27 -0800 (PST) Date: Thu, 25 Jan 2018 08:47:23 -0800 From: "hch@infradead.org" Subject: Re: [LSF/MM TOPIC] Filesystem-DAX, page-pinning, and RDMA Message-ID: <20180125164723.GA31752@infradead.org> References: <1516852902.3724.4.camel@wdc.com> <20180125160848.GE10706@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180125160848.GE10706@ziepe.ca> Sender: owner-linux-mm@kvack.org List-ID: To: Jason Gunthorpe Cc: Dan Williams , Bart Van Assche , "lsf-pc@lists.linux-foundation.org" , "hch@infradead.org" , "linux-mm@kvack.org" , "mhocko@kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvdimm@lists.01.org" On Thu, Jan 25, 2018 at 09:08:48AM -0700, Jason Gunthorpe wrote: > On Wed, Jan 24, 2018 at 11:02:16PM -0800, Dan Williams wrote: > > > No, in 3 dimensions since there is a need to support non-ODP RDMA > > hardware, hypervisors want to coordinate DMA for guests, and non-RDMA > > hardware also pins memory indefinitely like V4L2. So it's bigger than > > RDMA, but that will likely be the first consumer of this 'longterm > > pin' mechanism. > > BTW, did you look at VFIO? I think it should also have this problem > right? VFIO seems to have the same issue. In practice I don't think people use file system backed pages for vfio, so it's not as urgent. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org