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From: "hch@infradead.org" <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Bart Van Assche <Bart.VanAssche@wdc.com>,
	"lsf-pc@lists.linux-foundation.org"
	<lsf-pc@lists.linux-foundation.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"mhocko@kernel.org" <mhocko@kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>
Subject: Re: [LSF/MM TOPIC] Filesystem-DAX, page-pinning, and RDMA
Date: Thu, 25 Jan 2018 08:47:23 -0800	[thread overview]
Message-ID: <20180125164723.GA31752@infradead.org> (raw)
In-Reply-To: <20180125160848.GE10706@ziepe.ca>

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.

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  reply	other threads:[~2018-01-25 16:47 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-25  3:56 [LSF/MM TOPIC] Filesystem-DAX, page-pinning, and RDMA Dan Williams
2018-01-25  4:01 ` Bart Van Assche
2018-01-25  7:02   ` Dan Williams
2018-01-25 16:08     ` Jason Gunthorpe
2018-01-25 16:47       ` hch [this message]
2018-01-25  7:23 ` Christoph Hellwig
2018-01-25 16:08   ` Jason Gunthorpe
2018-01-25 16:47     ` Christoph Hellwig
2018-01-27  2:50       ` Dan Williams
2019-04-05 23:01         ` Jason Gunthorpe
2018-01-29 23:33 ` Jerome Glisse
2018-02-01 23:27   ` Jason Gunthorpe

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