From: "Paul E. McKenney" <paulmck@kernel.org> To: Nick Desaulniers <ndesaulniers@google.com> Cc: Boqun Feng <boqun.feng@gmail.com>, Peter Zijlstra <peterz@infradead.org>, ojeda@kernel.org, Linus Torvalds <torvalds@linux-foundation.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Alan Stern <stern@rowland.harvard.edu>, Andrea Parri <parri.andrea@gmail.com>, Will Deacon <will@kernel.org>, Nicholas Piggin <npiggin@gmail.com>, David Howells <dhowells@redhat.com>, Jade Alglave <j.alglave@ucl.ac.uk>, Luc Maranget <luc.maranget@inria.fr>, Akira Yokosawa <akiyks@gmail.com>, Daniel Lustig <dlustig@nvidia.com>, Joel Fernandes <joel@joelfernandes.org>, Josh Triplett <josh@joshtriplett.org>, Wedson Almeida Filho <wedsonaf@google.com> Subject: Re: [PATCH 00/13] [RFC] Rust support Date: Fri, 16 Apr 2021 11:47:13 -0700 [thread overview] Message-ID: <20210416184713.GI4212@paulmck-ThinkPad-P17-Gen-1> (raw) In-Reply-To: <CAKwvOdnRx+8LhOAnH24CeZz2a2-MwF03oB7Um_pKBq8WAoLNxw@mail.gmail.com> On Thu, Apr 15, 2021 at 11:04:37PM -0700, Nick Desaulniers wrote: > On Thu, Apr 15, 2021 at 9:27 PM Boqun Feng <boqun.feng@gmail.com> wrote: > > > > [Copy LKMM people, Josh, Nick and Wedson] > > > > On Thu, Apr 15, 2021 at 08:58:16PM +0200, Peter Zijlstra wrote: > > > On Wed, Apr 14, 2021 at 08:45:51PM +0200, ojeda@kernel.org wrote: > > > > > > > Rust is a systems programming language that brings several key > > > > advantages over C in the context of the Linux kernel: > > > > > > > > - No undefined behavior in the safe subset (when unsafe code is > > > > sound), including memory safety and the absence of data races. > > > > > > And yet I see not a single mention of the Rust Memory Model and how it > > > aligns (or not) with the LKMM. The C11 memory model for example is a > > > really poor fit for LKMM. > > > > > > > I think Rust currently uses C11 memory model as per: > > > > https://doc.rust-lang.org/nomicon/atomics.html > > > > , also I guess another reason that they pick C11 memory model is because > > LLVM has the support by default. > > > > But I think the Rust Community still wants to have a good memory model, > > and they are open to any kind of suggestion and input. I think we (LKMM > > people) should really get involved, because the recent discussion on > > RISC-V's atomics shows that if we didn't people might get a "broken" > > design because they thought C11 memory model is good enough: > > > > https://lore.kernel.org/lkml/YGyZPCxJYGOvqYZQ@boqun-archlinux/ > > > > And the benefits are mutual: a) Linux Kernel Memory Model (LKMM) is > > defined by combining the requirements of developers and the behavior of > > hardwares, it's pratical and can be a very good input for memory model > > designing in Rust; b) Once Rust has a better memory model, the compiler > > technologies whatever Rust compilers use to suppor the memory model can > > be adopted to C compilers and we can get that part for free. > > Yes, I agree; I think that's a very good approach. Avoiding the ISO > WG14 is interesting; at least the merits could be debated in the > public and not behind closed doors. WG14 (C) and WG21 (C++) are at least somewhat open. Here are some of the proposals a few of us have in flight: P2055R0 A Relaxed Guide to memory_order_relaxed http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p2055r0.pdf P0124R7 Linux-Kernel Memory Model (vs. that of C/C++) http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p0124r7.html P1726R4 Pointer lifetime-end zap http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1726r4.pdf https://docs.google.com/document/d/1MfagxTa6H0rTxtq9Oxyh4X53NzKqOt7y3hZBVzO_LMk/edit?usp=sharing P1121R2 Hazard Pointers: Proposed Interface and Wording for Concurrency TS 2 http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1121r2.pdf P1382R1 volatile_load<T> and volatile_store<T> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1382r1.pdf P1122R2 Proposed Wording for Concurrent Data Structures: Read-Copy-Update (RCU) http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1122r2.pdf https://docs.google.com/document/d/1MfagxTa6H0rTxtq9Oxyh4X53NzKqOt7y3hZBVzO_LMk/edit?usp=sharing P0190R4 Proposal for New memory order consume Definition http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0190r4.pdf P0750R1 Consume http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0750r1.html P1726R4 is of particular concern, along with consume. > > At least I personally is very intereted to help Rust on a complete and > > pratical memory model ;-) > > > > Josh, I think it's good if we can connect to the people working on Rust > > memoryg model, I think the right person is Ralf Jung and the right place > > is https://github.com/rust-lang/unsafe-code-guidelines, but you > > cerntainly know better than me ;-) Or maybe we can use Rust-for-Linux or > > linux-toolchains list to discuss. > > > > [...] > > > > - Boqun Feng is working hard on the different options for > > > > threading abstractions and has reviewed most of the `sync` PRs. > > > > > > Boqun, I know you're familiar with LKMM, can you please talk about how > > > Rust does things and how it interacts? > > > > As Wedson said in the other email, currently there is no code requiring > > synchronization between C side and Rust side, so we are currently fine. > > But in the longer term, we need to teach Rust memory model about the > > "design patterns" used in Linux kernel for parallel programming. > > > > What I have been doing so far is reviewing patches which have memory > > orderings in Rust-for-Linux project, try to make sure we don't include > > memory ordering bugs for the beginning. I believe that compatibility with both C/C++ and the Linux kernel are important. Thanx, Paul
next prev parent reply other threads:[~2021-04-16 18:47 UTC|newest] Thread overview: 189+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-14 18:45 ojeda 2021-04-14 18:45 ` [PATCH 01/13] kallsyms: Support "big" kernel symbols (2-byte lengths) ojeda 2021-04-14 19:44 ` Matthew Wilcox 2021-04-14 19:59 ` Miguel Ojeda 2021-04-14 18:45 ` [PATCH 02/13] kallsyms: Increase maximum kernel symbol length to 512 ojeda 2021-04-14 23:48 ` Nick Desaulniers 2021-04-14 18:45 ` [PATCH 03/13] Makefile: Generate CLANG_FLAGS even in GCC builds ojeda 2021-04-14 18:59 ` Nathan Chancellor 2021-04-15 10:18 ` Miguel Ojeda 2021-04-14 23:46 ` Nick Desaulniers 2021-04-15 0:47 ` Miguel Ojeda 2021-04-14 18:45 ` [PATCH 04/13] Kbuild: Rust support ojeda 2021-04-14 23:19 ` Nick Desaulniers 2021-04-15 0:43 ` Miguel Ojeda 2021-04-15 18:03 ` Nick Desaulniers 2021-04-16 12:23 ` Miguel Ojeda 2021-04-17 19:35 ` Masahiro Yamada 2021-04-16 13:38 ` Peter Zijlstra 2021-04-16 17:05 ` Linus Torvalds 2021-04-16 17:47 ` Miguel Ojeda 2021-04-16 18:09 ` Al Viro 2021-04-16 18:57 ` Miguel Ojeda 2021-04-16 20:22 ` Willy Tarreau 2021-04-16 20:34 ` Connor Kuehl 2021-04-16 20:58 ` Willy Tarreau 2021-04-16 21:39 ` Miguel Ojeda 2021-04-16 22:04 ` Willy Tarreau 2021-04-16 22:45 ` Al Viro 2021-04-16 23:46 ` Miguel Ojeda 2021-04-17 4:24 ` Willy Tarreau 2021-04-17 15:38 ` Miguel Ojeda 2021-04-16 21:19 ` Miguel Ojeda 2021-04-16 17:34 ` Miguel Ojeda 2021-04-19 19:58 ` David Sterba 2021-04-19 20:17 ` Matthew Wilcox 2021-04-19 21:03 ` Miguel Ojeda 2021-04-19 20:54 ` Miguel Ojeda 2021-04-14 18:45 ` [PATCH 05/13] Rust: Compiler builtins crate ojeda 2021-04-14 19:19 ` Linus Torvalds 2021-04-14 19:34 ` Miguel Ojeda 2021-04-14 18:45 ` [PATCH 06/13] Rust: Module crate ojeda 2021-04-14 18:45 ` [PATCH 07/13] Rust: Kernel crate ojeda 2021-04-14 19:31 ` Linus Torvalds 2021-04-14 19:50 ` Miguel Ojeda 2021-04-14 18:45 ` [PATCH 08/13] Rust: Export generated symbols ojeda 2021-04-14 18:46 ` [PATCH 09/13] Samples: Rust examples ojeda 2021-04-14 19:34 ` Linus Torvalds 2021-04-14 19:42 ` Miguel Ojeda 2021-04-14 19:49 ` Matthew Wilcox 2021-04-16 11:46 ` Andrej Shadura 2021-04-14 23:24 ` Nick Desaulniers 2021-04-15 7:10 ` Greg Kroah-Hartman 2021-04-15 7:39 ` Nick Desaulniers 2021-04-15 12:42 ` Miguel Ojeda 2021-04-16 13:07 ` Sven Van Asbroeck 2021-04-16 13:20 ` Greg Kroah-Hartman 2021-04-14 18:46 ` [PATCH 10/13] Documentation: Rust general information ojeda 2021-04-14 22:17 ` Nick Desaulniers 2021-04-14 23:34 ` Miguel Ojeda 2021-04-14 18:46 ` [PATCH 11/13] MAINTAINERS: Rust ojeda 2021-04-14 21:55 ` Nick Desaulniers 2021-04-14 22:02 ` Miguel Ojeda 2021-04-14 22:36 ` Nick Desaulniers 2021-04-14 18:46 ` [PATCH 12/13] Rust: add abstractions for Binder (WIP) ojeda 2021-04-14 18:46 ` [PATCH 13/13] Android: Binder IPC in Rust (WIP) ojeda 2021-04-14 19:44 ` [PATCH 00/13] [RFC] Rust support Linus Torvalds 2021-04-14 20:20 ` Miguel Ojeda 2021-04-15 1:38 ` Kees Cook 2021-04-15 8:26 ` David Laight 2021-04-15 18:08 ` Kees Cook 2021-04-15 12:39 ` Miguel Ojeda 2021-04-14 20:09 ` Matthew Wilcox 2021-04-14 20:21 ` Linus Torvalds 2021-04-14 20:35 ` Josh Triplett 2021-04-14 22:08 ` David Laight 2021-04-14 20:29 ` Miguel Ojeda 2021-04-18 15:31 ` Wedson Almeida Filho 2021-04-15 0:22 ` Nick Desaulniers 2021-04-15 10:05 ` Miguel Ojeda 2021-04-15 18:58 ` Peter Zijlstra 2021-04-16 2:22 ` Wedson Almeida Filho 2021-04-16 4:25 ` Al Viro 2021-04-16 5:02 ` Wedson Almeida Filho 2021-04-16 5:39 ` Paul Zimmerman 2021-04-16 7:46 ` Peter Zijlstra 2021-04-16 7:09 ` Peter Zijlstra 2021-04-17 5:23 ` comex 2021-04-17 12:46 ` David Laight 2021-04-17 14:51 ` Paolo Bonzini 2021-04-19 7:32 ` Peter Zijlstra 2021-04-19 7:53 ` Paolo Bonzini 2021-04-19 8:26 ` Peter Zijlstra 2021-04-19 8:35 ` Peter Zijlstra 2021-04-19 9:02 ` Paolo Bonzini 2021-04-19 9:36 ` Peter Zijlstra 2021-04-19 9:40 ` Paolo Bonzini 2021-04-19 11:01 ` Will Deacon 2021-04-19 17:14 ` Linus Torvalds 2021-04-19 18:38 ` Paolo Bonzini 2021-04-19 18:50 ` Linus Torvalds 2021-04-22 10:03 ` Linus Walleij 2021-04-22 14:09 ` David Laight 2021-04-22 15:24 ` Wedson Almeida Filho 2021-04-26 0:18 ` Linus Walleij 2021-04-26 14:26 ` Miguel Ojeda 2021-04-26 14:40 ` Wedson Almeida Filho 2021-04-26 16:03 ` Miguel Ojeda 2021-04-27 10:54 ` Linus Walleij 2021-04-27 11:13 ` Robin Randhawa 2021-04-29 1:52 ` Wedson Almeida Filho 2021-04-26 18:01 ` Miguel Ojeda 2021-04-22 21:28 ` Miguel Ojeda 2021-04-26 0:31 ` Linus Walleij 2021-04-26 18:18 ` Miguel Ojeda 2021-04-27 11:13 ` Linus Walleij 2021-04-28 2:51 ` Kyle Strand 2021-04-28 3:10 ` Miguel Ojeda 2021-05-04 21:21 ` Linus Walleij 2021-05-04 23:30 ` Miguel Ojeda 2021-05-05 11:34 ` Linus Walleij 2021-05-05 14:17 ` Miguel Ojeda 2021-05-05 15:13 ` Enrico Weigelt, metux IT consult 2021-05-06 12:47 ` Linus Walleij 2021-05-07 18:23 ` Miguel Ojeda 2021-04-16 4:27 ` Boqun Feng 2021-04-16 6:04 ` Nick Desaulniers 2021-04-16 18:47 ` Paul E. McKenney [this message] 2021-04-19 20:35 ` Nick Desaulniers 2021-04-19 21:37 ` Paul E. McKenney 2021-04-19 22:03 ` Miguel Ojeda 2021-04-16 20:48 ` Josh Triplett 2021-04-16 8:16 ` Michal Kubecek 2021-04-16 9:29 ` Willy Tarreau 2021-04-16 11:24 ` Peter Zijlstra 2021-04-16 13:07 ` Wedson Almeida Filho 2021-04-16 14:19 ` Peter Zijlstra 2021-04-16 15:04 ` Miguel Ojeda 2021-04-16 15:43 ` Peter Zijlstra 2021-04-16 16:21 ` Miguel Ojeda 2021-04-16 15:33 ` Wedson Almeida Filho 2021-04-16 16:14 ` Willy Tarreau 2021-04-16 17:10 ` Miguel Ojeda 2021-04-16 17:18 ` Peter Zijlstra 2021-04-16 18:08 ` Matthew Wilcox 2021-04-17 11:17 ` Peter Zijlstra 2021-04-17 11:46 ` Willy Tarreau 2021-04-17 14:24 ` Peter Zijlstra 2021-04-17 14:36 ` Willy Tarreau 2021-04-17 13:46 ` David Laight 2021-04-16 17:37 ` Willy Tarreau 2021-04-16 17:46 ` Connor Kuehl 2021-04-20 0:24 ` Nick Desaulniers 2021-04-20 3:47 ` Willy Tarreau 2021-04-20 5:56 ` Greg Kroah-Hartman 2021-04-20 6:16 ` Willy Tarreau 2021-04-29 15:38 ` peter enderborg 2021-04-17 13:53 ` Wedson Almeida Filho 2021-04-17 14:21 ` Willy Tarreau 2021-04-17 15:23 ` Miguel Ojeda 2021-04-18 15:51 ` Wedson Almeida Filho 2021-04-17 12:41 ` David Laight 2021-04-17 13:01 ` Wedson Almeida Filho 2021-04-16 15:03 ` Matthew Wilcox 2021-04-17 13:29 ` Wedson Almeida Filho 2021-04-16 15:58 ` Theodore Ts'o 2021-04-16 16:21 ` Wedson Almeida Filho 2021-04-17 15:11 ` Paolo Bonzini 2021-04-16 14:21 ` Miguel Ojeda 2021-04-17 20:42 ` Richard Weinberger 2021-04-28 18:34 ` Mariusz Ceier 2021-04-28 20:25 ` Nick Desaulniers 2021-04-28 21:21 ` David Laight 2021-04-29 11:14 ` Kajetan Puchalski 2021-04-29 11:25 ` Kajetan Puchalski 2021-04-29 14:06 ` Mariusz Ceier 2021-04-29 14:13 ` Sven Van Asbroeck 2021-04-29 14:26 ` Willy Tarreau 2021-04-29 15:06 ` Al Viro 2021-04-29 16:09 ` Mariusz Ceier 2021-04-30 6:39 ` Thomas Schoebel-Theuer 2021-04-30 8:30 ` David Laight 2021-05-05 13:58 ` Enrico Weigelt, metux IT consult 2021-05-05 14:41 ` Miguel Ojeda 2022-06-20 15:11 ` Olliver Schinagl 2022-06-27 17:44 ` Miguel Ojeda 2021-04-29 5:20 Mariusz Ceier 2021-04-29 5:21 Mariusz Ceier 2021-04-29 8:18 ` David Laight 2021-07-30 23:22 Dillan Jackson
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