The Linux Kernel's Long-Term Support Dilemma: Why 2 Years Isn't Enough for Everyone
The Linux 6.18 kernel, the latest long-term support (LTS) release, is here, but its arrival wasn't without a few bumps in the road. Linus Torvalds, the creator of the Linux kernel, expressed his dissatisfaction with the final days leading up to the release, wishing for fewer last-minute bug fixes. Despite this, he deemed it ready for prime time, stating, “While there’s a few more fixes than I would hope for, there was nothing that made me feel like this needs more time to cook.”
But here's where it gets controversial: the concept of “long-term support” for the Linux kernel has undergone a significant shift. Once boasting six years of support, LTS kernels now only receive two years of official maintenance. And this is the part most people miss: this reduction is directly linked to the burnout experienced by Linux code maintainers, who often work tirelessly without adequate compensation. As Josef Bacik, a Linux kernel file system developer, aptly put it, “Maintainers are burning out [because] maintainers don’t scale.”
The clock started ticking on December 3rd for Linux 6.18, with stable kernel maintainer Greg Kroah-Hartman officially designating it as the newest LTS version. This release also marks the end of support for Linux 5.4.
So, what does this mean for users? While two years of official LTS might seem insufficient for some, especially in enterprise environments, many top Linux distributors offer extended support options. Red Hat, for instance, provides over 10 years of support for its Red Hat Enterprise Linux (RHEL) kernels, ensuring stability and security for its paying customers. Similarly, SUSE offers a staggering 16 years of support for its SUSE Linux Enterprise Server (SLES) 16 and its Linux 6.12 kernel. Canonical, the company behind Ubuntu, extends support for its LTS kernels up to 15 years with add-on packages.
These commercially supported LTS kernels are crucial for developers and enterprises alike. As Kroah-Hartman emphasized, they provide a stable application binary interface (ABI) and a continuous stream of security patches, making them far safer than relying on outdated, non-LTS kernels or attempting to manually apply fixes.
Now, let's dive into what's new in Linux 6.18. At its core, this release features a significant upgrade to the slab memory allocator with the introduction of “sheaves,” a per-CPU cache mechanism that enhances memory allocation and freeing operations. It also boasts improved swapping behavior and virtual machine (VM) tweaks for better performance under memory pressure.
One of the most debated changes is the removal of the experimental Bcachefs file system from the mainline kernel. This decision stemmed from conflicts between its maintainer, Kent Overstreet, and kernel maintainers, including Torvalds, over patch timing and communication. Bcachefs is now available as a Dynamic Kernel Module Support (DKMS) module, requiring distributions to build and ship it separately if they wish to support it.
Linux 6.18 also brings advancements in networking, including support for Accurate Explicit Congestion Notification (AccECN) in TCP for improved throughput under load, and PSP-encrypted TCP connections as an alternative to traditional IPsec or TLS. Security is further strengthened with support for cryptographically signed BPF programs, enabling runtime-verified eBPF payloads.
Infrastructure improvements include the ability to manage process namespaces using file-handle-like objects, enhancing the robustness of container runtimes. Additionally, the integration of Rust into the kernel continues, with support for a Rust Binder driver, a Google-driven rewrite of the Android Binder driver.
As expected, Linux 6.18 includes a plethora of new and updated drivers across various architectures, improved GPU, SoC, and storage controller support, and enhancements for handheld gaming PCs and laptops. For end users, this translates to better out-of-the-box hardware compatibility in upcoming distributions.
But the question remains: is two years of official LTS enough? For desktop users, the benefits of Linux 6.18—faster memory allocation, improved network efficiency, and broader hardware support—are undeniable. However, server operators and cloud providers may find the extended support options from commercial distributors more appealing, especially with the focus on hybrid storage, TCP capabilities, and signed BPF infrastructure.
Linux 6.18 positions itself as a conservative yet foundational release, likely to become the standard for many distributions in the coming years. But as the debate over LTS duration continues, it raises a thought-provoking question: How can the open-source community better support its maintainers to ensure the longevity and sustainability of projects like the Linux kernel? We’d love to hear your thoughts in the comments below.
