From: Wedson Almeida Filho <wedsonaf@google.com> To: Willy Tarreau <w@1wt.eu> Cc: 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 Subject: Re: [PATCH 00/13] [RFC] Rust support Date: Sat, 17 Apr 2021 14:53:10 +0100 [thread overview] Message-ID: <YHroRuI7lYDABWJR@google.com> (raw) In-Reply-To: <20210416161444.GA10484@1wt.eu> On Fri, Apr 16, 2021 at 06:14:44PM +0200, Willy Tarreau wrote: > But will this remain syntactically readable/writable by mere humans ? I would certainly hope so. > > Note that this is > > another area where Rust offers advantages: read-only guards (in C, if you take a > > read lock, nothing prevents you from making changes to fields you should only be > > allowed to read); > > But I'm happily doing that when I know what I'm doing. What you call a > read lock usually is in fact a shared lock as opposed to an exclusive > lock (generally used for writes). For me it's perfectly valid to perform > atomic writes under a read lock instead of forcing everyone to wait by > taking a write lock. You may for example take a read lock on a structure > to make sure that a field you're accessing in it points to stable memory > that is only modified under the write lock, but the pointer itself is > atomically accessed and swapped under the read lock. Yes, this is a great example. Also easily expressible in Rust: they have this concept of interior mutability where certain types allow their contents to be modified even when shared immutably. Atomics offer such interior mutability, so the scenario you describe is fine. Rust in fact has an extra enforcement here that C doesn't: it requires interior mutability for this scenario to be allowed, so you can't do it with a plain naked type (say u64) -- you'd need to use something like an atomic64_t, where you're required to specify memory ordering when accessing them. In C we of course have atomics but the compiler never alerts us for when we need them. > > In fact, this is also an advantage of Rust. It would *force* developers to > > lock/unlock the RCU lock before they can access the protected data. > > I'm really afraid by languages which force developers to do this or that. When I say that Rust forces developers to do certain things, it's to provide the compile-time safety guarantees. Some of these requirements are imposed by our own abstractions -- we can always revisit and try to improve them. In cases when the abstractions cannot be further refined, developers always have the escape hatch of unsafety, where they're allowed to do pretty much everything as in C, but then they also give up the compile-time guarantees for those parts.
next prev parent reply other threads:[~2021-04-17 13:53 UTC|newest] Thread overview: 201+ 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 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 [this message] 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 2022-07-18 6:56 ` Olliver Schinagl 2022-07-20 19:23 ` Miguel Ojeda 2022-07-20 20:21 ` Nicolas Pitre 2022-07-27 7:47 ` Olliver Schinagl 2022-07-27 13:32 ` Nicolas Pitre 2022-07-27 8:05 ` Olliver Schinagl 2022-07-28 10:21 ` Gary Guo 2022-07-28 12:09 ` Greg Kroah-Hartman 2022-07-28 12:28 ` Gary Guo 2022-07-28 20:45 ` Olliver Schinagl 2022-07-29 8:04 ` Greg Kroah-Hartman 2022-07-28 20:43 ` Olliver Schinagl 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
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=YHroRuI7lYDABWJR@google.com \ --to=wedsonaf@google.com \ --cc=gregkh@linuxfoundation.org \ --cc=linux-doc@vger.kernel.org \ --cc=linux-kbuild@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=ojeda@kernel.org \ --cc=peterz@infradead.org \ --cc=rust-for-linux@vger.kernel.org \ --cc=torvalds@linux-foundation.org \ --cc=w@1wt.eu \ --subject='Re: [PATCH 00/13] [RFC] Rust support' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).