linux-kernel - Re: [PATCH v3 5/5] rust_binder: use bitmap for allocation of handles

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Message-ID: <aQ5s0Ajt26javMbH@google.com>
Date: Fri, 7 Nov 2025 22:04:00 +0000
From: Carlos Llamas <cmllamas@...gle.com>
To: Alice Ryhl <aliceryhl@...gle.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Yury Norov <yury.norov@...il.com>,
	Arve Hjønnevåg <arve@...roid.com>,
	Todd Kjos <tkjos@...roid.com>, Martijn Coenen <maco@...roid.com>,
	Joel Fernandes <joelagnelf@...dia.com>,
	Christian Brauner <brauner@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>, Burak Emir <bqe@...gle.com>,
	Miguel Ojeda <ojeda@...nel.org>, Boqun Feng <boqun.feng@...il.com>,
	Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <lossin@...nel.org>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	Trevor Gross <tmgross@...ch.edu>,
	Danilo Krummrich <dakr@...nel.org>, rust-for-linux@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 5/5] rust_binder: use bitmap for allocation of handles

On Tue, Oct 28, 2025 at 10:55:18AM +0000, Alice Ryhl wrote:
> To find an unused Binder handle, Rust Binder currently iterates the
> red/black tree from the beginning until it finds a gap in the keys. This
> is extremely slow.
> 
> To improve the performance, add a bitmap that keeps track of which
> indices are actually in use. This allows us to quickly find an unused
> key in the red/black tree.
> 
> This logic matches the approach used by C Binder. It was chosen
> partially because it's the most memory efficient solution.
> 
> Reviewed-by: Burak Emir <bqe@...gle.com>
> Signed-off-by: Alice Ryhl <aliceryhl@...gle.com>
> ---

LGTM,

Acked-by: Carlos Llamas <cmllamas@...gle.com>