Linux 7.3 is out: VRAM protection, scheduler tuning, Btrfs and SMB

Linux 7.3 has been out since Sunday 18 October 2026, and Torvalds described a quiet last week. linuxnews.de counts 18,765 commits from 3,021 developers, 807 of them new to the kernel. That is a record for participation, but for admins it is a footnote. Four changes matter more: they touch servers, GPU boxes and file servers.

Sources: linuxnews.de (19 October 2026) and heise online (20 October 2026). The heise report is partly behind the heise+ paywall; we only used the freely readable part. (Quelle: Simple Icons, file linux.svg (CC0))

Video memory with a protection level

The biggest change for graphics cards builds on Device Memory Control Groups (dmemcg). Applications can be given a preferred share of VRAM and count as protected. The protection is meant to keep a protected application from having to spill into system RAM when video memory is full. How the kernel redistributes memory for that is not in the freely readable part of the heise report. Before, an app that started late on a full card had to fall back to the slower system memory through the Graphics Translation Table (GTT).

Schematic, based on heise online's description. According to heise this is the first part of a larger overhaul. (Quelle: heise online, 20 October 2026)

heise names AMD GPUs and Intel Xe as beneficiaries and describes the target as systems with 8 GB of VRAM or less. On cards with plenty of memory you will notice little. linuxnews.de credits part of the work to Valve and talks about games that need more video memory than the card has. For NVIDIA, both reports only mention the open Nouveau driver (Blackwell, power management, Vulkan Video via NVK).

That matters for our own machines too. The four RTX 5090 cards on 192.168.180.3 run kernel 7.0.0-31 with a patched NVIDIA module for GPU-to-GPU P2P. 7.3 adds nothing to memory handling there, and a kernel change would silently revert the patch because DKMS rebuilds the stock module. Anyone running a similar setup should not treat this as a routine update.

Scheduler: sched_ext with subschedulers

For sched_ext, the eBPF-programmable scheduler, subscheduler support is now complete. The freely readable parts of the reports say no more; details on delegation sit behind heise's paywall.

The default EEVDF scheduler was also reworked for machines with many cores. linuxnews.de says overhead and latency drop, mainly on workstations and servers. Neither source gives measurements. If you run many containers on a large host, compare your own latencies before and after.

File systems: Btrfs, NTFS and SMB

Btrfs drops the first version of the free-space cache, long deprecated. Existing filesystems keep working but can get slower until they move to the newer cache version. This part goes beyond the reports: before switching kernels, run findmnt -t btrfs -o TARGET,OPTIONS to see which filesystems still use space_cache=v1, and practise the conversion on a test system first.

The NTFS3 driver gains basic support for Alternate Data Streams, which Windows uses, so file exchange gets easier. The in-kernel SMB server ksmbd now supports Apple Time Machine, and SMB3 encryption can be enabled per share. For an office NAS with mixed clients this is the change you are most likely to notice.

Security and hardware in brief

AppArmor can load compressed policies, and Landlock gets more options for restricting processes. On the hardware side there is Zen 6 support, a first driver base for Apple M3 Pro, Max and Ultra (linuxnews.de says no fully usable system yet) and the new Steam Controller. The Xe3P graphics of the upcoming Nova Lake processors are enabled by default.

What we take from it

Linux 7.3 is not an urgent update for production servers. Operators with Btrfs and ksmbd should run the test first. Owners of large NVIDIA video memory have little to gain. The next kernel, 7.4, is meant to be the last of the year and may have an unusual schedule because of Torvalds' vacation. Anyone who plans an update cycle anyway can start with 7.3 and wait for 7.4.