Linux kernel 6.13 brings lazy preemption, enhanced virtualization & broader device support

Linux kernel 6.13 has been launched with several features including the lazy preemption, which simplifies preemption logic and configurations, potentially reducing scheduler-related calls and boosting performance. The new IORING_REGISTER_RING_RESIZE command optimizes memory usage in io_uring by allowing dynamic memory resizing based on I/O demands. Additionally, the workqueue concurrency limit has been significantly increased from 512 to 2048, enhancing stability and performance, especially in server environments. Architectural improvements include support for older iPhone and iPad chips (A7 to A11), expanding Linux's compatibility with a broader range of devices.

The release also brings notable advancements in virtualization and filesystems. A new virtual CPUfreq driver optimizes performance and power in virtual machines by coordinating vCPU frequencies, while ARM Confidential Compute Architecture (CCA) support is introduced for ARM64 systems. Filesystem updates include atomic write support for Ext4 and XFS, improving data integrity during power or hardware failures. Btrfs now features encoded reads via io_uring and improved subvolume management, though ReiserFS has been removed.

Other enhancements include a Broadcom V3D driver update for Raspberry Pi, expanding device support, and storage improvements such as support for SDUC memory cards up to 128TB and NVMe 2.1 specification. Rust integration is expanded, and hardware support is enhanced with features like AMD P-State support for EPYC 9005 processors, improved crypto performance, and better GPU configurations for AMD and Intel hardware.