Daily update · Aug 20, 2026
Linux 7.3 merge window: sched_ext hierarchy, filesystem speedups, and io_uring zcrx updates
Highlights from the first batch of 7.3 pull requests.
In brief
The 7.3 merge window brings major scheduler extensibility, filesystem performance work, and I/O improvements. sched_ext now supports hierarchical sub-scheduling, while btrfs and ext4 land performance and safety changes. io_uring gains dynamic zero-copy RX provisioning.
Scheduler
sched_ext hierarchical sub-scheduling
The sched_ext pull request completes enqueue-path support for hierarchical sub-scheduling, letting a root BPF scheduler delegate cgroup subtrees to nested sub-schedulers with revocable CPU grants.
Why it matters: BPF scheduler authors can now build more flexible, multi-level CPU allocation policies.
Filesystems
Btrfs defaults to free space tree v2
Btrfs disables the old space cache v1 by default and requires read-only mounts for rescue=usebackuproot, while removing the standalone mount option.
Why it matters: Filesystems created with v1 may be slightly slower; recovery via backup root is now safer.
ext4 parallel direct I/O and prefetch improvements
ext4 allows parallel direct I/O writes when safe and optimizes fallocate prefetch, plus cleans up EA inode deallocation.
Why it matters: Better performance for concurrent DIO workloads and fallocate on ext4.
I/O and block
io_uring dynamic zero-copy RX provisioning
io_uring's zcrx work adds dynamic area provisioning, scales refilling with large pages, and fixes futex inflight accounting.
Why it matters: More flexible zero-copy receive buffers and fewer accounting bugs for futex waits.
NVMe/TCP memory disclosure fixes and rdma parallel setup
The block pull request includes fixes for nvme-tcp read path memory disclosure, parallelizes nvme-rdma queue allocation, and adds Clang context analysis.
Why it matters: Security fixes for NVMe over TCP and faster queue setup on RDMA.
Architecture
RISC-V ISA extension discovery and cache flushing
RISC-V adds initial definitions for many new ISA extensions and improves update_mmu_cache_range() using flush-by-ASID and Svinval.
Why it matters: Better performance and hardware support on RISC-V systems.
Source commits1180 entries +
Merge tag 'sysctl-7.03-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Linus Torvalds · Aug 20, 2026 · 25 files
Merge tag 'docs-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux
Linus Torvalds · Aug 20, 2026 · 85 files
Merge tag 'wq-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Linus Torvalds · Aug 20, 2026 · 4 files
Merge tag 'cgroup-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Linus Torvalds · Aug 20, 2026 · 18 files
Merge tag 'sched_ext-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Linus Torvalds · Aug 20, 2026 · 49 files
Merge tag 'kcsan-20260817-v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/melver/linux
Linus Torvalds · Aug 20, 2026 · 1 files
Merge tag 'bitmap-for-7.3' of https://github.com/norov/linux
Linus Torvalds · Aug 20, 2026 · 68 files
Merge tag 'execve-v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Linus Torvalds · Aug 20, 2026 · 1 files
Merge tag 'libnvdimm-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Linus Torvalds · Aug 20, 2026 · 10 files
Merge tag 'erofs-for-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Linus Torvalds · Aug 20, 2026 · 8 files
Merge tag 'ntfs3_for_7.3' of https://github.com/Paragon-Software-Group/linux-ntfs3
Linus Torvalds · Aug 20, 2026 · 17 files
Merge tag 'for-linus-7.3-ofs1' of git://git.kernel.org/pub/scm/linux/kernel/git/hubcap/linux
Linus Torvalds · Aug 20, 2026 · 4 files
Merge tag 'nfsd-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
Linus Torvalds · Aug 20, 2026 · 117 files
Merge tag 'fsnotify_for_v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Linus Torvalds · Aug 20, 2026 · 5 files
Merge tag 'fs_for_v7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Linus Torvalds · Aug 20, 2026 · 21 files
Merge tag 'for-7.3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Linus Torvalds · Aug 20, 2026 · 42 files
Merge tag 'ext4_for_linus-7.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Linus Torvalds · Aug 20, 2026 · 25 files
Merge tag 'for-7.3/io_uring-20260819' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Linus Torvalds · Aug 20, 2026 · 22 files
Merge tag 'for-7.3/block-20260819' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Linus Torvalds · Aug 20, 2026 · 136 files
Merge tag 'loongarch-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
Linus Torvalds · Aug 20, 2026 · 11 files
Merge tag 'm68k-for-v7.3-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
Linus Torvalds · Aug 20, 2026 · 15 files
Merge tag 'riscv-for-linus-7.3-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Linus Torvalds · Aug 20, 2026 · 50 files
Merge tag 'cxl-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl
Linus Torvalds · Aug 20, 2026 · 27 files
Merge tag 'probes-v7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Linus Torvalds · Aug 20, 2026 · 31 files
Merge tag 'printk-for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Linus Torvalds · Aug 20, 2026 · 3 files
Merge tag 'vfio-v7.3-rc1' of https://github.com/awilliam/linux-vfio
Linus Torvalds · Aug 20, 2026 · 33 files