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Linux 7.3 released with GPU VRAM management, Btrfs/Ext4 gains, and sched_ext completion

Brief written by the FOSSWire AI editor from CNX Software How we write

1 min read

Key Takeaway

Linux 7.3 brings completed sched_ext BPF-based cgroup sub-schedulers, improved VRAM contention handling for low-end GPUs, and significant Btrfs and Ext4 filesystem performance improvements.

Summary

Linus Torvalds released Linux 7.3 on schedule, with the merge window for 7.4 opening immediately after. The release completes the sched_ext implementation for BPF-based per-cgroup task scheduling. Filesystem improvements include Btrfs Direct I/O performance recovery and up to 5x faster fsync with no-holes, plus Ext4 direct I/O parallel write and fallocate() gains. Low-end GPUs benefit from dmem cgroup-based VRAM eviction to reduce application ping-ponging. FUSE io_uring gains zero-copy and buffer pool support. Architecture work spans Allwinner A733, Rockchip RV1106 and RK3576/RK3588 boards, Amlogic A1/T7/A9, Samsung Exynos 8855/1580 and ExynosAuto v920, and Qualcomm's new 'Shikra' Cortex-A78C SoC.

What's in Linux 7.3 for developers and embedded

  • sched_ext completion: cgroup sub-schedulers now fully functional, allowing per-cgroup BPF-based task schedulers with different policies per cgroup
  • GPU VRAM: dmem cgroup enables eviction of unprotected buffers instead of immediate backoff when applications compete for limited VRAM
  • Btrfs: Direct I/O performance restored; 1 jiffy delay removed for non-SSD logging workloads yielding 5x throughput increase; fsync with no-holes (default since btrfs-progs 5.15) 5x faster
  • Ext4: direct I/O parallel writes and fallocate() improved; buffered-write regression fixed
  • FUSE io_uring: kernel buffer pools reduce memory requirements; zero-copy path added
  • Arm/RISC-V/MIPS: extensive SoC and board support additions including Rockchip RV1106, RK3576, RK3588 variants; Qualcomm 'Shikra'; Samsung Exynos 8855/1580, ExynosAuto v920; Allwinner A733

Why it matters

The completed sched_ext enables production use of programmable per-cgroup scheduling, potentially improving latency-critical workloads. Embedded and SBC users gain substantial new hardware support across Rockchip, Qualcomm, Samsung, and Allwinner platforms.

What to do

  • Update to Linux 7.3 to get completed sched_ext BPF-based cgroup sub-schedulers, improved VRAM management for low-end GPUs, and Btrfs/Ext4 performance improvements.
  • If you use Btrfs with non-SSD disks, ensure the no-holes feature is enabled (default since btrfs-progs 5.15) for up to 5x faster fsync performance.
  • If you run FUSE filesystems with io_uring, update to Linux 7.3 to benefit from kernel buffer pools and zero-copy support that reduce memory usage and improve performance.
  • Users of low-end GPUs should update to Linux 7.3 so the dmem cgroup can evict unprotected buffers instead of immediately backing off when applications compete for limited VRAM.

Original reference: www.cnx-software.com →