From: Alice Ryhl <aliceryhl@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Lyude Paul" <lyude@redhat.com>,
linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org,
"Benno Lossin" <lossin@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@redhat.com>, "Will Deacon" <will@kernel.org>,
"Boqun Feng" <boqun.feng@gmail.com>,
"Waiman Long" <longman@redhat.com>,
"Miguel Ojeda" <ojeda@kernel.org>,
"Alex Gaynor" <alex.gaynor@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
"Andreas Hindborg" <a.hindborg@kernel.org>,
"Trevor Gross" <tmgross@umich.edu>,
"Danilo Krummrich" <dakr@kernel.org>
Subject: Re: [PATCH v4] rust: lock: Export Guard::do_unlocked()
Date: Fri, 31 Oct 2025 10:24:38 +0000 [thread overview]
Message-ID: <aQSOZu7nN56Uqj6V@google.com> (raw)
In-Reply-To: <288ba4d2-b7db-46cf-b979-341a58613fc0@redhat.com>
On Fri, Oct 31, 2025 at 10:38:32AM +0100, Paolo Bonzini wrote:
> On 10/31/25 10:31, Alice Ryhl wrote:
> > I do agree that this behavior has a lot of potential to surprise
> > users, but I don't think it's incorrect per se. It was done
> > intentionally for Condvar, and it's not unsound. Just surprising.
>
> Yes, I agree that it is not unsound.`
>
> For conditional variables, wait() is clearly going to release the mutex to
> wait for someone else so the surprise factor is much less. Having it return
> a new guard would be closer to std::sync::Condvar::wait, but it'd add churn
> and I'm not sure how much you all care about consistency with std. std has
> the extra constraint of poisoned locks so it doesn't really have a choice.
I mean, it's not that much different.
my_method(&mut guard);
might still call Condvar::wait internally, so it can release the lock
today.
Alice
next prev parent reply other threads:[~2025-10-31 10:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 18:35 [PATCH v4] rust: lock: Export Guard::do_unlocked() Lyude Paul
2025-10-30 10:43 ` Paolo Bonzini
2025-10-30 17:41 ` Lyude Paul
2025-10-31 9:31 ` Alice Ryhl
2025-10-31 9:38 ` Paolo Bonzini
2025-10-31 10:24 ` Alice Ryhl [this message]
2025-11-05 20:41 ` Lyude Paul
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