From: Ira Weiny <ira.weiny@intel.com>
To: John Hubbard <jhubbard@nvidia.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Christoph Hellwig" <hch@infradead.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Dave Chinner" <david@fromorbit.com>, "Jan Kara" <jack@suse.cz>,
"Jason Gunthorpe" <jgg@ziepe.ca>,
"Jérôme Glisse" <jglisse@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
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()
Date: Wed, 14 Aug 2019 16:50:00 -0700 [thread overview]
Message-ID: <20190814234959.GA463@iweiny-DESK2.sc.intel.com> (raw)
In-Reply-To: <90e5cd11-fb34-6913-351b-a5cc6e24d85d@nvidia.com>
On Tue, Aug 13, 2019 at 05:56:31PM -0700, John Hubbard wrote:
> On 8/13/19 5:51 PM, John Hubbard wrote:
> > On 8/13/19 2:08 PM, Ira Weiny wrote:
> >> On Mon, Aug 12, 2019 at 05:07:32PM -0700, John Hubbard wrote:
> >>> On 8/12/19 4:49 PM, Ira Weiny wrote:
> >>>> On Sun, Aug 11, 2019 at 06:50:44PM -0700, john.hubbard@gmail.com wrote:
> >>>>> From: John Hubbard <jhubbard@nvidia.com>
> >>> ...
> >> Finally, I struggle with converting everyone to a new call. It is more
> >> overhead to use vaddr_pin in the call above because now the GUP code is going
> >> to associate a file pin object with that file when in ODP we don't need that
> >> because the pages can move around.
> >
> > What if the pages in ODP are file-backed?
> >
>
> oops, strike that, you're right: in that case, even the file system case is covered.
> Don't mind me. :)
Ok so are we agreed we will drop the patch to the ODP code? I'm going to keep
the FOLL_PIN flag and addition in the vaddr_pin_pages.
Ira
>
> >>
> >> This overhead may be fine, not sure in this case, but I don't see everyone
> >> wanting it.
>
> So now I see why you said that, but I will note that ODP hardware is rare,
> and will likely remain rare: replayable page faults require really special
> hardware, and after all this time, we still only have CPUs, GPUs, and the
> Mellanox cards that do it.
>
> That leaves a lot of other hardware to take care of.
>
> thanks,
> --
> John Hubbard
> NVIDIA
>
next prev parent reply other threads:[~2019-08-14 23:50 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-12 1:50 [RFC PATCH 0/2] mm/gup: introduce vaddr_pin_pages_remote(), FOLL_PIN john.hubbard
2019-08-12 1:50 ` [RFC PATCH 1/2] mm/gup: introduce FOLL_PIN flag for get_user_pages() john.hubbard
2019-08-12 1:50 ` [RFC PATCH 2/2] mm/gup: introduce vaddr_pin_pages_remote() john.hubbard
2019-08-12 22:03 ` Ira Weiny
2019-08-12 22:21 ` John Hubbard
2019-08-12 23:49 ` Ira Weiny
2019-08-13 0:07 ` John Hubbard
2019-08-13 21:08 ` Ira Weiny
2019-08-14 0:51 ` John Hubbard
2019-08-14 0:56 ` John Hubbard
2019-08-14 23:50 ` Ira Weiny [this message]
2019-08-15 0:02 ` John Hubbard
2019-08-15 3:01 ` John Hubbard
2019-08-15 13:26 ` Jan Kara
2019-08-15 13:35 ` Jan Kara
2019-08-15 14:51 ` Jason Gunthorpe
2019-08-15 17:32 ` Ira Weiny
2019-08-15 17:41 ` John Hubbard
2019-08-16 2:14 ` John Hubbard
2019-08-16 15:41 ` Jan Kara
2019-08-16 18:33 ` Ira Weiny
2019-08-16 18:50 ` John Hubbard
2019-08-16 21:59 ` Ira Weiny
2019-08-16 22:36 ` John Hubbard
2019-08-16 8:47 ` Vlastimil Babka
2019-08-16 15:44 ` Jan Kara
2019-08-16 15:52 ` Jerome Glisse
2019-08-16 16:13 ` Jan Kara
2019-08-16 16:31 ` Jason Gunthorpe
2019-08-16 16:54 ` Jerome Glisse
2019-08-16 17:04 ` Jason Gunthorpe
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