Open Source Summit North America 2025

Data access monitoring and access-aware system operations based on it can be very useful and efficient when it is used wisely. Otherwise, it can be useless or even harmful. Hence, users are often required to do time-consuming and repetitive testing and tuning. It is not only data access monitoring's problem but a common issue at system-level operations.

DAMON is a Linux kernel subsystem for efficient data access monitoring and access-aware system operations. It mitigates the tuning problem by embedding a few automation mechanisms that allows users to run it in an automated for best outputs, but still safely controlled way.

This talk introduces the tuning problem and DAMON's automation mechanisms in detail, with usage guidelines and evaluation results. Audiences will be able to understand how they can use DAMON for more efficient system, and get some ideas about how to solve the tuning problems in general.

The latest RISC-V ISA specification allows for runtime configuration of the data endian between little and big. Since no one had done this before, we decided to investigate how difficult it would be to get a prototype Linux implementation running in big endian on an emulated RISC-V system such as under QEMU.

The talk goes from the description of the new ISA feature, our initial analysis and the modifications to software such as the Linux kernel, QEMU and OpenSBI and an overview of the issues that we found and how to fix them. This includes kvm and how that works with mixed endian kvm instances, and the modifications to kvmtool to make this work.

We conclude with how the project went, what we published and a call to arms to continue testing and fixing outstanding issues.

The volume of processing data is growing exponentially. AI/ML algorithms, financial transactions, social networks, cloud computing represent modern trends that latency, performance sensitive, and data hungry. File systems represent crucial and fundamental technology that builds foundation of data storage stack. However, pressure of data-centric and data-intensive nature of modern applications revealed significant overhead that file systems introduce in data storage stack. Moreover, massive amount of hardware accelerator and kernel bypassing technologies, dis-aggregated architecture, ultra-fast storage devices create “illusion” or “impression” that file systems could be a redundant item of data storage stack. Can file systems survive in data-centric world?

COSMIC DE is a new, full-featured desktop environment (like GNOME and KDE) written from scratch in the Rust programming language. It does not rely on GTK or Qt. Instead COSMIC uses a new Rust GUI toolkit called iced and the system76 developed libcosmic toolkit for building interfaces and applications with advanced theming and customization features.

COSMIC DE includes a suite of first-party applications including a file browser, text editor, application store, settings, and terminal. There is also a growing community of third-party apps. COSMIC includes a custom compositor that features variable refresh rate, Xwayland support, animations, fractional scaling, modern hybrid graphics features, window snapping and auto-tiling.

What makes COSMIC truly unique is that it's the first modular, composable desktop environment. For a user that means they can easily adapt COSMIC to their preferred workflow. Linux distributions can create wholly unique user experiences.
And companies can develop unique products using COSMIC.

Carl will discuss why system76 built COSMIC DE, show its features, and demonstrate how unique experiences can be composed with COSMIC DE.

Achieving end-to-end data integrity is essential for modern storage systems, yet Linux still faces challenges in providing full-stack protection. This session explores recent improvements in Linux’s data integrity framework. Specifically this presentation shares detail about:

1. A new io_uring interface that enables applications to attach metadata with I/O requests, ensuring robust data protection.

2. Optimizations to existing integrity mechanisms that improve performance, reduce overhead, and enhance flexibility, all of which have been merged into the mainline kernel.

3. Lastly, we highlight a novel mechanism that allows filesystems to fully utilize device integrity features and helps optimizing host and device resource utilization.

This presentation will deliver in-depth technical insights into these advancements and their role in strengthening Linux storage reliability.

The Linux ecosystem—spanning upstream mainline, stable and LTS branches, and downstream distributions like Ubuntu and Android—relies on patch porting to ensure stability and security. However, concerns persist about delayed or incomplete patch propagation. By mining software repositories across 28 Linux branches (e.g., Android,Ubuntu,Debian,OpenSLE and etc) and 584K patches., we uncover diverse patch porting strategies and their trade-offs, measured through patch delay, patch rate, and bug inheritance ratio. We also analyze the factors influcing the patch porting practices and offer actionable insights to enhance patch flow efficiency and strengthen the Linux ecosystem.

We present the Rex project (https://github.com/rex-rs/rex). Rex is a Linux kernel extension framework that allows extension programs to be written in safe Rust. Rex offers similar safety guarantees to eBPF. Unlike eBPF-based tools like Aya, Rex extensions are not compiled into eBPF bytecode. Rex eliminates the in-kernel verifier – the safety of Rex extensions is built atop language-based safety plus runtime protection. Specifically, the Rex compiler enforces Rex extensions to be written in a subset of safe Rust, and emits native code directly. Rex implements its kernel crate with a safe interface that wraps existing eBPF interface. Rex also employs a lightweight runtime that implements graceful Rust panic handling with resource cleanups, kernel stack checks, and program termination.

Rex provides a more usable and arguably safer alternative to eBPF. The usability advantage comes from the elimination of in-kernel verifiers that are known to reject safe extension programs with cryptic feedback. We also show that Rex’s runtime protection provides stronger safety than eBPF in a few aspects, e.g., protecting kernel stacks from overflowing.

More details: https://tinyurl.com/y8uj8ypp