From: Matthew Wilcox <willy@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: David Hildenbrand <david@redhat.com>,
Chih-En Lin <shiyn.lin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>,
William Kucharski <william.kucharski@oracle.com>,
John Hubbard <jhubbard@nvidia.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Arnd Bergmann <arnd@arndb.de>,
Suren Baghdasaryan <surenb@google.com>,
Colin Cross <ccross@google.com>, Feng Tang <feng.tang@intel.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Mike Rapoport <rppt@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Daniel Axtens <dja@axtens.net>,
Jonathan Marek <jonathan@marek.ca>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Peter Xu <peterx@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Fenghua Yu <fenghua.yu@intel.com>,
linux-kernel@vger.kernel.org, Kaiyang Zhao <zhao776@purdue.edu>,
Huichun Feng <foxhoundsk.tw@gmail.com>,
Jim Huang <jserv.tw@gmail.com>
Subject: Re: [RFC PATCH 0/6] Introduce Copy-On-Write to Page Table
Date: Sun, 22 May 2022 01:31:02 +0100 [thread overview]
Message-ID: <YomERsAM3gF7XxRZ@casper.infradead.org> (raw)
In-Reply-To: <64d0da08-6ffd-4bce-bc66-5097913937b4@kernel.org>
On Sat, May 21, 2022 at 03:19:24PM -0700, Andy Lutomirski wrote:
> I can see a rather different use for this type of shared-pagetable
> technology, though: monstrous MAP_SHARED mappings. For database and some VM
> users, multiple processes will map the same file. If there was a way to
> ensure appropriate alignment (or at least encourage it) and a way to handle
> mappings that don't cover the whole file, then having multiple mappings
> share the same page tables could be a decent efficiently gain. This doesn't
> even need COW -- it's "just" pagetable sharing.
The mshare proposal did not get a warm reception at LSFMM ;-(
The conceptual model doesn't seem to work for the MM developers who were
in the room. "Fear" was the most-used word. Not sure how we're going
to get to a model of sharing page tables that doesn't scare people.
next prev parent reply other threads:[~2022-05-22 0:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-19 18:31 [RFC PATCH 0/6] Introduce Copy-On-Write to Page Table Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 1/6] mm: Add a new mm flag for Copy-On-Write PTE table Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 2/6] mm: clone3: Add CLONE_COW_PGTABLE flag Chih-En Lin
2022-05-20 14:13 ` Christophe Leroy
2022-05-21 3:50 ` Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 3/6] mm, pgtable: Add ownership for the PTE table Chih-En Lin
2022-05-20 14:15 ` Christophe Leroy
2022-05-21 4:03 ` Chih-En Lin
2022-05-21 4:02 ` Matthew Wilcox
2022-05-21 5:01 ` Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 4/6] mm: Add COW PTE fallback function Chih-En Lin
2022-05-20 14:21 ` Christophe Leroy
2022-05-21 4:15 ` Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 5/6] mm, pgtable: Add the reference counter for COW PTE Chih-En Lin
2022-05-20 14:30 ` Christophe Leroy
2022-05-21 4:22 ` Chih-En Lin
2022-05-21 4:08 ` Matthew Wilcox
2022-05-21 5:10 ` Chih-En Lin
2022-05-19 18:31 ` [RFC PATCH 6/6] mm: Expand Copy-On-Write to PTE table Chih-En Lin
2022-05-20 14:49 ` Christophe Leroy
2022-05-21 4:38 ` Chih-En Lin
2022-05-21 8:59 ` [External] [RFC PATCH 0/6] Introduce Copy-On-Write to Page Table Qi Zheng
2022-05-21 19:08 ` Chih-En Lin
2022-05-21 16:07 ` David Hildenbrand
2022-05-21 18:50 ` Chih-En Lin
2022-05-21 20:28 ` David Hildenbrand
2022-05-21 20:12 ` Matthew Wilcox
2022-05-21 20:22 ` David Hildenbrand
2022-05-21 22:19 ` Andy Lutomirski
2022-05-22 0:31 ` Matthew Wilcox [this message]
2022-05-22 15:20 ` Andy Lutomirski
2022-05-22 19:40 ` Matthew Wilcox
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