Oracle has shipped its Oracle Linux kernel, the Unbreakable Enterprise Kernel 8, bringing a ꩵnumber o🅺f improvements to memory management, file system support, and more.

Oracle is a major player in the enterprise Linux space, and ships its own “purpose-built Oracle Linux kernel” as part of it. The company has shipped its latest version, version 8, which the company is touting as its best yet.

“This is our eighth release of UEK, and I think it’s the best one yet,” , 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.”

Memory Improvements

One of the main new features in UEK 8 is improved memory m🅰anagement.

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 manage⭕ment 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.

UEK 8 also includes improvements to Ampere Arm-based memory🐼 management.

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.

File System Improvements

UEK 8 brings a numbღer of file system😼 improvements, including better I/O security and file system 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.

Btrfs also sees some performance improvements.

For the Btrfs file system, UEK 8 delivers performance improvements such as the ability to send or receive compressed data without transformation and haꦚn☂dle 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.

Btrfs is an advanced copy-on-write (COW) filesystem that offers compression, self-healing capabilities, and native snapshot integration. Unfortunately, because o🥂f its COW nature, Btrfs can be a bit slower than traditional alternatives, such as ✃EXT4.

For XFS filesystem users, UEK 8 also adds XFS 🔯Online Repair as a technology preview.

Misc Improvements

UEK 8 incl🌟udes additional improvement﷽s to improve the security of the Oracle Linux.

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 manyꦗ 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 sendꦛing 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.

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.

All-in-all, UEK 8 is a su💯bstantial upgrade, and one that system admins will likely want to install sooner rather than later.