From: Peter Zijlstra <peterz@infradead.org>
To: Gary Guo <gary@garyguo.net>
Cc: "Alice Ryhl" <aliceryhl@google.com>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Lorenzo Stoakes" <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Benno Lossin" <lossin@kernel.org>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>,
"Will Deacon" <will@kernel.org>,
"Mark Rutland" <mark.rutland@arm.com>,
linux-mm@kvack.org, rust-for-linux@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] rust: page: add byte-wise atomic memory copy methods
Date: Wed, 18 Feb 2026 11:20:45 +0100 [thread overview]
Message-ID: <20260218102045.GD1282955@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <67aea464d25c8cafb3113eea62c8221b@garyguo.net>
On Tue, Feb 17, 2026 at 11:10:15PM +0000, Gary Guo wrote:
> If we have this in stable, I think it's sufficient for LKMM. However
> for Rust/C11 MM says that volatile ops are not atomic and use them for
> concurrency is UB.
>
> I recall in last Rust all hands the vibe at discussion is that it's
> desirable to define volatile as being byte-wise atomic, so if that
> actually happens, this would indeed be what we want (but I think
> semantics w.r.t. mixed-size atomics need to be figured out first).
I would strongly suggest for volatile to be single-copy 'atomic' for any
naturally aligned word sized access. This is what we have with
GCC/Clang.
If you pick anything else, you're explicitly creation interoperability
issues.
next prev parent reply other threads:[~2026-02-18 10:20 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-13 6:42 Andreas Hindborg
2026-02-13 11:28 ` Peter Zijlstra
2026-02-13 12:45 ` Andreas Hindborg
2026-02-13 14:35 ` Peter Zijlstra
2026-02-13 16:42 ` Boqun Feng
2026-02-14 8:18 ` Andreas Hindborg
2026-02-17 18:47 ` Boqun Feng
2026-02-13 17:44 ` Boqun Feng
2026-02-14 8:04 ` Andreas Hindborg
2026-02-17 8:55 ` Peter Zijlstra
2026-02-17 9:42 ` Gary Guo
2026-02-17 10:47 ` Will Deacon
2026-02-17 17:10 ` Boqun Feng
2026-02-18 8:53 ` Peter Zijlstra
2026-02-18 11:20 ` Peter Zijlstra
2026-02-17 12:03 ` Alice Ryhl
2026-02-17 17:32 ` Boqun Feng
2026-02-17 23:10 ` Gary Guo
2026-02-18 9:40 ` Alice Ryhl
2026-02-18 10:20 ` Peter Zijlstra [this message]
2026-02-18 11:36 ` Gary Guo
2026-02-18 12:12 ` Peter Zijlstra
2026-02-18 11:56 ` Miguel Ojeda
2026-02-18 12:00 ` Alice Ryhl
2026-02-18 12:07 ` Miguel Ojeda
2026-02-18 12:33 ` Andreas Hindborg
2026-02-18 14:42 ` Benno Lossin
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