# Linux 7.3 extends dmem cgroup to nouveau, adds VRAM reclaim on limit reduction

> **Key takeaway:** Linux 7.3 adds nouveau driver support for the dmem cgroup controller and fixes silent failures when lowering VRAM limits by adding a blocking reclaim mechanism.

**Published:** 2026-10-20T17:19:57+00:00 
**Source:** Planet Debian (Developer Blogs) 
**Category:** distro-planet 
**Canonical URL:** https://fosswire.org/news/linux-73-extends-dmem-cgroup-to-nouveau-adds-vram-reclaim-on.html 

## Summary
The dmem cgroup controller, introduced in Linux 6.14 for restricting GPU VRAM usage per workload, gains nouveau support in Linux 7.3 following earlier Intel Xe and AMD amdgpu adoption. The release also adds dmem.peak for tracking peak VRAM usage, fixes allocation failures near min/low thresholds, and replaces silent failures with an explicit reclaim mechanism when lowering dmem.max below current usage.

## What's new in dmem for Linux 7.3
- **dmem.peak**: New read-only file exposing peak VRAM usage per region per cgroup
- **Allocation fix**: Cgroups can now allocate up to their min/low limits even when uncontrolled processes have consumed most VRAM
- **Atomic writes**: Single-region-per-write enforced; previous multi-region writes could partially fail silently
- **Reclaim on limit reduction**: Lowering dmem.max below current usage now triggers blocking reclaim (respects O_NONBLOCK); previously failed silently without reducing usage

## Why it matters
With all three major open-source GPU drivers now supporting dmem, container and desktop users can reliably cap browser, game, or AI workload VRAM usage to prevent compositor starvation or noisy-neighbor problems in shared GPU environments.