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From: Barry Song <21cnbao@gmail.com>
To: khalid.aziz@oracle.com
Cc: akpm@linux-foundation.org, arnd@arndb.de,
	dave.hansen@linux.intel.com, david@redhat.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	longpeng2@huawei.com, rppt@kernel.org, surenb@google.com,
	willy@infradead.org
Subject: Re: [RFC PATCH 0/6] Add support for shared PTEs across processes
Date: Fri, 21 Jan 2022 09:08:06 +0800	[thread overview]
Message-ID: <20220121010806.5607-1-21cnbao@gmail.com> (raw)
In-Reply-To: <cover.1642526745.git.khalid.aziz@oracle.com>

> A file under /sys/fs/mshare can be opened and read from. A read from
> this file returns two long values - (1) starting address, and (2)
> size of the mshare'd region.
> 
> --
> int mshare_unlink(char *name)
> 
> A shared address range created by mshare() can be destroyed using
> mshare_unlink() which removes the  shared named object. Once all
> processes have unmapped the shared object, the shared address range
> references are de-allocated and destroyed.

> mshare_unlink() returns 0 on success or -1 on error.

I am still struggling with the user scenarios of these new APIs. This patch
supposes multiple processes will have same virtual address for the shared
area? How can this be guaranteed while different processes can map different
stack, heap, libraries, files?

BTW, it seems you have different intention with the below?
Shared page tables during fork[1]
[1] https://lwn.net/Articles/861547/

Thanks
Barry



  parent reply	other threads:[~2022-01-21  1:08 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-18 21:19 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 [this message]
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
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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