Linux 6.19 Released

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"The first Linux kernel release of 2026"

Linux 6.19 Released

Linux 6.19 is the first release of 2026, shipping several contributions from Igalia among its more than 14 thousand commits — keeping up the consistent work from last year. Have a look at our 2025 retrospective! For an overview of this kernel release and features, check the KernelNewbies page.

Once again, our team delivered improvements, features, and bug fixes across different areas of the kernel — ranging from debugging and core infrastructure to filesystems, energy model, graphics drivers and APIs, and more; helping our clients in many domains and benefiting the wider Linux community.

Speaking of the Linux community, as previously announced, some of our contributions and related work were presented at the Linux Plumbers Conference 2025, discussing their context, challenges, and more details. In the sections below, we provide links to individual talk videos on Youtube.

The next section describes Igalia’s contributions to Linux 6.19.

Igalia Changelog

page_owner improvements

In the memory management subsystem, page_owner is a debug feature for memory allocations. It stores the stack trace of the memory allocation of every page, and can report which stack trace allocated a page and how many pages are allocated by a stack trace, among other things.

We have improved page_owner’s userspace interface in debugfs, providing options to reduce the amount of data produced by the kernel and consumed by userspace, which allows for more efficient continuous data collection.

This is helpful for use cases such as profiling and monitoring the memory allocation/usage in the system, which page_owner can do with page granularity plus stack trace insight.

More details are available in the presentation at the Linux Plumbers Conference 2025.

Futex improvements

Continuing the effort made in 6.18, we once again made improvements on the Futex selftests. This time we added the kernel seftests for the set/get_robust_list() syscalls. Despite this syscall being around for about 20 years, it never had a test in the kernel tree… until now! The new selftest provides a good coverage and should track regressions when modifying the robust_list internals, and also can be used as a documentation about how to use this uAPI.

These improvements on the futex system call are part of a big effort on adding a new interface for the set_robust_list(). You can learn more about this in the Linux Plumbers Conference 2025 presentation.

FUSE periodic dentries invalidation

Filesystem in Userspace (FUSE) caching is usually handled at the kernel level by the FUSE subsystem. Obviously, the data cached by the kernel needs to be maintained as it can either: 1) be explicitly marked as invalid by the FUSE user-space server, or 2) become too old, by means of having a timeout associated with it.

We have just added a new mechanism to periodically invalidate the FUSE cached data. This mechanism includes the infrastructure to keep all the dentries sorted by expiry time in a tree structure so that expired data can be efficiently invalidated. To enable this new feature, an extra FUSE module parameter was added. It can to be set to a value, in seconds, which will be the period for a workqueue that will take care of the invalidation of expired dentries.

Schedulers built on sched_ext, such as LAVD, must understand performance–power trade-offs to make informed, energy-aware scheduling decisions. The Linux kernel’s Energy Model (EM) provides this information, capturing details such as CPU cluster topology and the power cost associated with operating at specific CPU frequencies.

However, there is currently no suitable interface for accessing the Energy Model from either BPF programs or userspace. To address this limitation, we introduce a netlink interface that exposes Energy Model information for a given SoC. This interface allows userspace applications to query EM data and receive notifications when the model changes—for example, due to thermal condition updates.

With this patchset, sched_ext-based schedulers and related tooling can incorporate up-to-date energy characteristics into their decision-making process. More details on Energy Model–Aware Scheduling (EMAS) in LAVD are available in this presentation at the Linux Plumbers Conference 2025.

AMD GPU kernel driver improvements

We have added a capability to the common DRM TTM layer, where drivers are now able to hint above what allocation size it is not worth trying too hard to allocate contiguous memory. This allows for better worst case large buffer allocation latency under memory pressure, where the TTM layer will now not try to do direct memory reclaim above the configured threshold.

As kernel developers, we often need to load and unload modules multiple times for various reasons, one of the primary ones being to save time by avoiding system reboots. However, we encountered issues with the load/unload feature across multiple devices, including the Steam Deck. While we addressed problems for other devices, the APU, particularly in the Steam Deck, presented a unique challenge: the device must be reset during the unload/load sequence to ensure the firmware is in a proper state.

In this release, we implemented a fix that triggers a GPU reset on APUs at the time of unloading, effectively resolving the reload issue. Additionally, we observed that on Renoir devices, the reset was mistakenly applied during the loading phase, leading to increased latency during boot. Since the fix is applicable to all APUs, we can now remove the workaround for Renoir devices, which should improve boot speed on those systems.

New KMS Plane Color Management API

We actively participated in design, reviews and testing of the new KMS Plane Color Management API. With this new generic KMS API, kernel display drivers can expose their color capabilities before blending, allowing compositors to offload more color transformations to the display hardware (freeing the GPU for Graphics workload) for advanced color management and better HDR support. Moreover, most of the AMD support for this new API was based on our previous implementation of AMD driver-specific color management properties, a work we started with gamescope and got merged to the mainline kernel in 2023.

Other

We also contributed bug fixes to the amdgpu driver and a nfc driver, and an improvement in the sound subsystem, along with reviews, acks, and a maintainer sign-off.

Authored (42)

André Almeida

Changwoo Min

Luis Henriques

Mauricio Faria de Oliveira

Melissa Wen

Rodrigo Siqueira

Thadeu Lima de Souza Cascardo

Tvrtko Ursulin

Umang Jain

Reviewed (36)

Changwoo Min

André Almeida

Changwoo Min

Luis Henriques

Melissa Wen

Tvrtko Ursulin

Umang Jain

Acked (3)

Changwoo Min

Christian Gmeiner

Tvrtko Ursulin

Maintainer SoB (1)

Christian Gmeiner