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From: David Hildenbrand <david@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
	Khalid Aziz <khalid.aziz@oracle.com>,
	akpm@linux-foundation.org, longpeng2@huawei.com, arnd@arndb.de,
	dave.hansen@linux.intel.com, rppt@kernel.org, surenb@google.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Peter Xu <peterx@redhat.com>
Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes
Date: Wed, 26 Jan 2022 14:55:10 +0100	[thread overview]
Message-ID: <2190b8e2-74f2-0e31-0a40-0401fbd9966e@redhat.com> (raw)
In-Reply-To: <YfFO6VyMTrW1bWuu@casper.infradead.org>

On 26.01.22 14:38, Matthew Wilcox wrote:
> On Wed, Jan 26, 2022 at 11:16:42AM +0100, David Hildenbrand wrote:
>> A while ago I talked with Peter about an extended uffd (here: WP)
>> mechanism that would work on fds instead of the process address space.
> 
> As far as I can tell, uffd is a grotesque hack that exists to work around
> the poor choice to use anonymous memory instead of file-backed memory
> in kvm.  Every time I see somebody mention it, I feel pain.
> 

I might be missing something important, because KVM can deal with
file-back memory just fine and uffd is used heavily outside of hypervisors.

I'd love to learn how to handle what ordinary uffd (handle
missing/unpopulated pages) and uffd-wp (handle write access to pages)
can do with files instead. Because if something like that already
exists, it would be precisely what I am talking about.

Maybe mentioning uffd was a bad choice ;)

-- 
Thanks,

David / dhildenb



  reply	other threads:[~2022-01-26 13:55 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-18 21:19 [RFC PATCH 0/6] Add support for shared PTEs across processes Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 1/6] mm: Add new system calls mshare, mshare_unlink Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 2/6] mm: Add msharefs filesystem Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 3/6] mm: Add read for msharefs Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 4/6] mm: implement mshare_unlink syscall Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 5/6] mm: Add locking to msharefs syscalls Khalid Aziz
2022-01-18 21:19 ` [RFC PATCH 6/6] mm: Add basic page table sharing using mshare Khalid Aziz
2022-01-18 21:41 ` [RFC PATCH 0/6] Add support for shared PTEs across processes Dave Hansen
2022-01-18 21:46   ` Matthew Wilcox
2022-01-18 22:47     ` Khalid Aziz
2022-01-18 22:06 ` Dave Hansen
2022-01-18 22:52   ` Khalid Aziz
2022-01-19 11:38 ` Mark Hemment
2022-01-19 17:02   ` Khalid Aziz
2022-01-20 12:49     ` Mark Hemment
2022-01-20 19:15       ` Khalid Aziz
2022-01-24 15:15         ` Mark Hemment
2022-01-24 15:27           ` Matthew Wilcox
2022-01-24 22:20           ` Khalid Aziz
2022-01-21  1:08 ` Barry Song
2022-01-21  2:13   ` Matthew Wilcox
2022-01-21  7:35     ` Barry Song
2022-01-21 14:47       ` Matthew Wilcox
2022-01-21 16:41         ` Khalid Aziz
2022-01-22  1:39           ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2022-01-22  1:41             ` Matthew Wilcox
2022-01-22 10:18               ` Thomas Schoebel-Theuer
2022-01-22 16:09                 ` Matthew Wilcox
2022-01-22 11:31 ` Mike Rapoport
2022-01-22 18:29   ` Andy Lutomirski
2022-01-24 18:48   ` Khalid Aziz
2022-01-24 19:45     ` Andy Lutomirski
2022-01-24 22:30       ` Khalid Aziz
2022-01-24 23:16         ` Andy Lutomirski
2022-01-24 23:44           ` Khalid Aziz
2022-01-25 11:42 ` Kirill A. Shutemov
2022-01-25 12:09   ` William Kucharski
2022-01-25 13:18     ` David Hildenbrand
2022-01-25 14:01       ` Kirill A. Shutemov
2022-01-25 13:23   ` Matthew Wilcox
2022-01-25 13:59     ` Kirill A. Shutemov
2022-01-25 14:09       ` Matthew Wilcox
2022-01-25 18:57         ` Kirill A. Shutemov
2022-01-25 18:59           ` Matthew Wilcox
2022-01-26  4:04             ` Matthew Wilcox
2022-01-26 10:16               ` David Hildenbrand
2022-01-26 13:38                 ` Matthew Wilcox
2022-01-26 13:55                   ` David Hildenbrand [this message]
2022-01-26 14:12                     ` Matthew Wilcox
2022-01-26 14:30                       ` David Hildenbrand
2022-01-26 14:12                   ` Mike Rapoport
2022-01-26 13:42               ` Kirill A. Shutemov
2022-01-26 14:18                 ` Mike Rapoport
2022-01-26 17:33                   ` Khalid Aziz

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