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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Dave Chinner <david@fromorbit.com>
Cc: Jerome Glisse <jglisse@redhat.com>,
	John Hubbard <jhubbard@nvidia.com>,
	john.hubbard@gmail.com, Matthew Wilcox <willy@infradead.org>,
	Michal Hocko <mhocko@kernel.org>,
	Christopher Lameter <cl@linux.com>,
	Dan Williams <dan.j.williams@intel.com>, Jan Kara <jack@suse.cz>,
	Al Viro <viro@zeniv.linux.org.uk>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org,
	Christian Benvenuti <benve@cisco.com>,
	Dennis Dalessandro <dennis.dalessandro@intel.com>,
	Doug Ledford <dledford@redhat.com>,
	Mike Marciniszyn <mike.marciniszyn@intel.com>
Subject: Re: [PATCH 0/4] get_user_pages*() and RDMA: first steps
Date: Mon, 1 Oct 2018 09:31:01 -0600
Message-ID: <20181001153101.GA23286@ziepe.ca> (raw)
In-Reply-To: <20181001061127.GQ31060@dastard>

On Mon, Oct 01, 2018 at 04:11:27PM +1000, Dave Chinner wrote:

> This reminds me so much of Linux mmap() in the mid-2000s - mmap()
> worked for ext3 without being aware of page faults, so most mm/
> developers at the time were of the opinion that all the other
> filesystems should work just fine without being aware of page
> faults.

This is probably because RDMA was introduced around that time, before
page_mkwrite was added.. It kind of sounds like page_mkwrite() broke
all the writing get_user_pages users and it wasn't realized at the
time.

BTW, we are hosting a session on this at Plumbers during the RDMA
track, hope everyone interested will be able to attend.

Jason

  parent reply index

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-28  5:39 john.hubbard
2018-09-28  5:39 ` [PATCH 1/4] mm: get_user_pages: consolidate error handling john.hubbard
2018-09-28  5:39 ` [PATCH 3/4] infiniband/mm: convert to the new put_user_page() call john.hubbard
2018-09-28 15:39   ` Jason Gunthorpe
2018-09-29  3:12     ` John Hubbard
2018-09-29 16:21       ` Matthew Wilcox
2018-09-29 19:19         ` Jason Gunthorpe
2018-10-01 12:50         ` Christoph Hellwig
2018-10-01 15:29           ` Matthew Wilcox
2018-10-01 15:51             ` Christoph Hellwig
2018-10-01 14:35       ` Dennis Dalessandro
2018-10-03  5:40         ` John Hubbard
2018-10-03 16:27       ` Jan Kara
2018-10-03 23:19         ` John Hubbard
2018-09-28  5:39 ` [PATCH 2/4] mm: introduce put_user_page(), placeholder version john.hubbard
2018-10-03 16:22   ` Jan Kara
2018-10-03 23:23     ` John Hubbard
2018-09-28  5:39 ` [PATCH 4/4] goldfish_pipe/mm: convert to the new release_user_pages() call john.hubbard
2018-09-28 15:29 ` [PATCH 0/4] get_user_pages*() and RDMA: first steps Jerome Glisse
2018-09-28 19:06   ` John Hubbard
2018-09-28 21:49     ` Jerome Glisse
2018-09-29  2:28       ` John Hubbard
2018-09-29  8:46         ` Jerome Glisse
2018-10-01  6:11           ` Dave Chinner
2018-10-01 12:47             ` Christoph Hellwig
2018-10-02  1:14               ` Dave Chinner
2018-10-03 16:21                 ` Jan Kara
2018-10-01 15:31             ` Jason Gunthorpe [this message]
2018-10-03 16:08           ` Jan Kara

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