Oracle Corporation

04/15/2025 | Press release | Distributed by Public on 04/15/2025 22:29

Oracle Linux Now Includes the Latest Linux Kernel with UEK 8

The latest release of Oracle's purpose-built Oracle Linux kernel, the Unbreakable Enterprise Kernel 8 (UEK 8), unveils cutting-edge innovations including advancements in memory management, enhanced file system support, networking optimizations, platform-specific improvements, and a wide range of other enhancements from Oracle and the upstream Linux community. UEK 8, based on the latest upstream long-term stable kernel, is developed, built, tested, and supported on the 64-bit Intel and AMD (x86-64) and 64-bit Arm (aarch64) architectures.

"This is our eighth release of UEK, and I think it's the best one yet," said Greg Marsden, senior vice president of Linux software development, Oracle. "In addition to bringing in significant improvements like memory folios, UEK 8 is built on the foundation of the UEK-next project. For the past year, UEK-next has allowed both Oracle and our customers to test out the latest upstream features that are now production- and enterprise-ready with UEK 8. UEK has been around nearly as long as upstream stable kernels, and it continues to push the boundaries of Linux innovation and deliver the performance and stability that businesses depend on-while keeping Linux open and free."

Engineered for the most demanding workloads, UEK 8 builds on the proven dynamic combination of Oracle Linux and UEK to help meet the growing needs of customers' large enterprise deployments across distributed environments, including Oracle Database, Oracle Exadata, and Oracle Cloud Infrastructure (OCI).
What's new in UEK 8

Select features, enhancements, and changes introduced in this release are highlighted below. For more detailed information, refer to the UEK 8 Release Notes.
Optimized memory management

UEK 8 features a variety of significant memory management optimizations. Notably, the folios data structure replaces the struct page data structure to provide improved abstraction for managing memory pages, helping reduce overhead and increase scalability. Additionally, to improve the management of virtual memory areas for faster lookups, inserts, and deletes, the Red-Black Trees data structure has been replaced with the Maple Tree data structure. Maple Tree is a lockless B-tree data structure designed to efficiently use CPU cache, lower contention on the memory management subsystem, and, in turn, boost application performance.

For OCI Ampere Arm-based compute shapes, in addition to the standard UEK for Arm build, which sets a 4K base page size, a 64K base page size can now be configured. In smaller environments where increasing physical system memory isn't feasible due to resource, power, and cost constraints, the 4K page size kernel is beneficial. However, for organizations running Arm platforms processing workloads with large, contiguous memory datasets, such as those in high-performance computing, configuring a 64K page size can enhance performance for certain types of CPU- and memory-intensive operations by reducing page faults and increasing overall memory efficiency.
Enhanced I/O security and file systems performance

With this UEK release, io_uring, a system call interface to manage storage device asynchronous I/O operations, includes a range of features and security updates. These include improvements in buffered writes in the XFS file system and optimizations that enable XFS and Ext4 to handle multiple direct I/O writes to a file in parallel, resulting in higher I/O performance and better scalability for high-throughput workloads.

For the Btrfs file system, UEK 8 delivers performance improvements such as the ability to send or receive compressed data without transformation and handle data chunks larger than 64K for writes. In addition, UEK 8 introduces the ability to mount a file system with a block size larger than the page size for XFS, which can improve write performance and I/O efficiency. Finally, to enhance the handling of sparse files in the NFS file system, the NFSv4.2 READ_PLUS feature is now enabled by default within the kernel.

XFS Online Repair, a significant advancement for XFS, is now available as a technology preview feature with UEK 8. Notably, it enables automatic validation of XFS corruptions without unmounting the filesystem and automatic online repairs, to help minimize downtime and strengthen system reliability.
Advances in BPF and greater networking efficiency

Berkeley Packet Filter (BPF) continues to be integral in enabling developers to observe and modify kernel behavior by running programs verified to be safe before being injected into the kernel. Among many other important updates to BPF, a dedicated BPF memory allocator is introduced in this release to improve the reliability of allocations within BPF programs.

To improve networking throughput and reduce latencies when sending large IPv6 TCP packets on data center networks, BIG TCP is included in this release, enabling more efficient data transfer. Furthermore, to enhance TCP performance in environments with many concurrent connections, several core networking data structures have been reorganized for better cache efficiency.
Platform updates for scalable and secure environments

Alongside general platform updates, UEK 8 includes Intel-specific security technologies, such as Intel Software Guard Extensions for Enclave Dynamic Memory Management (SGX2). SGX2 debuts features such as dynamic memory management, allowing private memory regions, known as enclaves, to resize and manage their memory during runtime. Designed for applications with dynamic workloads or large memory requirements, SGX2 can help protect data and code by isolating them in these dedicated memory regions, presenting robust confidentiality and integrity for sensitive workloads in both on-premises and cloud environments.
Upgrading to UEK 8

UEK 8 is available for installation starting with Oracle Linux 9 Update 5. For detailed instructions on upgrading a system to UEK 8, refer to the Release Notes.

Note that systems running Oracle Linux 8 must first be upgraded to Oracle Linux 9 to install UEK 8. For guidance on upgrading your systems using the Leapp utility, review the following documentation for Oracle Linux 9. Systems running Oracle Linux 9 must be updated to the latest available update release before installing UEK 8.