Linus Torvalds has announced the release of Linux kernel 7.3, the latest stable version, following a development cycle that set new records for contributions and developer participation.
This release includes 18,765 non-merge commits from 3,021 developers, including 807 first-time contributors. All three figures are records, making Linux 7.3 one of the largest kernel releases to date in development activity.
One major change is a reworking of the kernel’s group scheduling mechanism to improve how CPU time is distributed among process groups. The changes reduce scheduling overhead and improve performance, especially on large systems running many workloads simultaneously.
The release also completes the subscheduler functionality in sched_ext, the framework that allows developers to implement custom CPU scheduling policies using BPF. This gives developers more flexibility when building schedulers for specialized workloads.
On the filesystem side, Linux 7.3 introduces FailFS, a small filesystem that deliberately fails file operations. Though unusual, it provides a useful way to restrict filesystem access when isolating processes. Another addition is the fchroot() system call, which lets a process change its root directory using a file descriptor instead of a pathname.
OverlayFS now supports id-mapped mounts, making it easier to manage file ownership in containerized environments. Btrfs drops its legacy free-space cache v1 implementation, while NTFS3 gains initial support for Windows alternative data streams.
The kernel’s built-in SMB server, ksmbd, also sees improvements, including support for Apple Time Machine backups, per-share SMB3 encryption, and encryption enhancements for SMB Direct connections. FUSE gains additional zero-copy I/O improvements through io_uring, reducing unnecessary data copying during filesystem operations.
Regarding memory management and virtualization, Linux 7.3 adds working-set tracking for virtual machines, offering better insight into which memory pages guests actively use. The DAMON subsystem gains additional monitoring capabilities, while the BPF infrastructure receives global per-CPU data support and other enhancements.
Hardware support expands with additional preparations for AMD Zen 6 processors, improvements for AMD graphics hardware, and further Intel graphics support, including work on upcoming Nova Lake GPUs. There are also updates for various Realtek wireless adapters, gaming handhelds, and ARM and RISC-V platforms.
For gamers, the release includes improvements to graphics memory management that help AMD GPUs with limited VRAM. Storage performance also sees optimizations, including work targeting ext4 I/O and high-speed NVMe devices.
Security-related changes include improvements to AppArmor policy loading, additional Landlock capabilities, and stricter handling of signed BPF programs. Rust support continues to grow as well, with new kernel abstractions and initial support for additional architectures, including PowerPC.
As for the final development week, Torvalds described it as uneventful, with fixes spread across different kernel subsystems and no particular problems standing out.
“It’s Sunday afternoon, and this week I somehow kept my wits together long enough to keep track of the day of the week, so the release isn’t randomly delayed. Will wonders never cease?”
With Linux 7.3 now available, the merge window for Linux 7.4 opens on October 19, although Torvalds warned that his annual family vacation could make his schedule somewhat unusual.
Linux kernel 7.3 is available for download from kernel.org. As usual, rolling-release distributions are expected to adopt it first, while other distributions will make it available according to their respective update schedules.
