From: Andrew Morton <akpm@linux-foundation.org>
To: "Jérôme Glisse" <jglisse@redhat.com>
Cc: <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, John Hubbard <jhubbard@nvidia.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
David Nellans <dnellans@nvidia.com>
Subject: Re: [HMM 00/16] HMM (Heterogeneous Memory Management) v18
Date: Thu, 16 Mar 2017 13:43:21 -0700 [thread overview]
Message-ID: <20170316134321.c5cf727c21abf89b7e6708a2@linux-foundation.org> (raw)
In-Reply-To: <1489680335-6594-1-git-send-email-jglisse@redhat.com>
On Thu, 16 Mar 2017 12:05:19 -0400 J__r__me Glisse <jglisse@redhat.com> wrote:
> Cliff note:
"Cliff's notes" isn't appropriate for a large feature such as this.
Where's the long-form description? One which permits readers to fully
understand the requirements, design, alternative designs, the
implementation, the interface(s), etc?
Have you ever spoken about HMM at a conference? If so, the supporting
presentation documents might help here. That's the level of detail
which should be presented here.
> HMM offers 2 things (each standing on its own). First
> it allows to use device memory transparently inside any process
> without any modifications to process program code.
Well. What is "device memory"? That's very vague. What are the
characteristics of this memory? Why is it a requirement that
userspace code be unaltered? What are the security implications - does
the process need particular permissions to access this memory? What is
the proposed interface to set up this access?
> Second it allows to mirror process address space on a device.
Why? Why is this a requirement, how will it be used, what are the
use cases, etc?
I spent a bit of time trying to locate a decent writeup of this feature
but wasn't able to locate one. I'm not seeing a Documentation/ update
in this patchset. Perhaps if you were to sit down and write a detailed
Documentation/vm/hmm.txt then that would be a good starting point.
This stuff is important - it's not really feasible to perform a decent
review of this proposal unless the reviewer has access to this
high-level conceptual stuff.
So I'll take a look at merging this code as-is for testing purposes but
I won't be attempting to review it at this stage.
next prev parent reply other threads:[~2017-03-16 20:43 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-16 16:05 Jérôme Glisse
2017-03-16 16:05 ` [HMM 01/16] mm/memory/hotplug: convert device bool to int to allow for more flags v3 Jérôme Glisse
2017-03-19 20:08 ` Mel Gorman
2017-03-16 16:05 ` [HMM 02/16] mm/put_page: move ref decrement to put_zone_device_page() Jérôme Glisse
2017-03-19 20:08 ` Mel Gorman
2017-03-16 16:05 ` [HMM 03/16] mm/ZONE_DEVICE/free-page: callback when page is freed v3 Jérôme Glisse
2017-03-19 20:08 ` Mel Gorman
2017-03-16 16:05 ` [HMM 04/16] mm/ZONE_DEVICE/unaddressable: add support for un-addressable device memory v3 Jérôme Glisse
2017-03-19 20:09 ` Mel Gorman
2017-03-16 16:05 ` [HMM 05/16] mm/ZONE_DEVICE/x86: add support for un-addressable device memory Jérôme Glisse
2017-03-16 16:05 ` [HMM 06/16] mm/migrate: add new boolean copy flag to migratepage() callback Jérôme Glisse
2017-03-19 20:09 ` Mel Gorman
2017-03-16 16:05 ` [HMM 07/16] mm/migrate: new memory migration helper for use with device memory v4 Jérôme Glisse
2017-03-16 16:24 ` Reza Arbab
2017-03-16 20:58 ` Balbir Singh
2017-03-16 23:05 ` Andrew Morton
2017-03-17 0:22 ` John Hubbard
2017-03-17 0:45 ` Balbir Singh
2017-03-17 0:57 ` John Hubbard
2017-03-17 1:52 ` Jerome Glisse
2017-03-17 3:32 ` Andrew Morton
2017-03-17 3:42 ` Balbir Singh
2017-03-17 4:51 ` Balbir Singh
2017-03-17 7:17 ` John Hubbard
2017-03-16 16:05 ` [HMM 08/16] mm/migrate: migrate_vma() unmap page from vma while collecting pages Jérôme Glisse
2017-03-16 16:05 ` [HMM 09/16] mm/hmm: heterogeneous memory management (HMM for short) Jérôme Glisse
2017-03-19 20:09 ` Mel Gorman
2017-03-16 16:05 ` [HMM 10/16] mm/hmm/mirror: mirror process address space on device with HMM helpers Jérôme Glisse
2017-03-19 20:09 ` Mel Gorman
2017-03-16 16:05 ` [HMM 11/16] mm/hmm/mirror: helper to snapshot CPU page table v2 Jérôme Glisse
2017-03-19 20:09 ` Mel Gorman
2017-03-16 16:05 ` [HMM 12/16] mm/hmm/mirror: device page fault handler Jérôme Glisse
2017-03-16 16:05 ` [HMM 13/16] mm/hmm/migrate: support un-addressable ZONE_DEVICE page in migration Jérôme Glisse
2017-03-16 16:05 ` [HMM 14/16] mm/migrate: allow migrate_vma() to alloc new page on empty entry Jérôme Glisse
2017-03-16 16:05 ` [HMM 15/16] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE Jérôme Glisse
2017-03-16 16:05 ` [HMM 16/16] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v2 Jérôme Glisse
2017-03-17 6:55 ` Bob Liu
2017-03-17 16:53 ` Jerome Glisse
2017-03-16 20:43 ` Andrew Morton [this message]
2017-03-16 23:49 ` [HMM 00/16] HMM (Heterogeneous Memory Management) v18 Jerome Glisse
2017-03-17 8:29 ` Bob Liu
2017-03-17 15:57 ` Jerome Glisse
2017-03-17 8:39 ` Bob Liu
2017-03-17 15:52 ` Jerome Glisse
2017-03-19 20:09 ` Mel Gorman
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