chore: release v2.2.6

[github-actions]

🤖 New release

• rusty_alloc: 2.2.5 -> 2.2.6 (✓ API compatible changes)
• rusty_alloc-api: 2.2.5 -> 2.2.6 (✓ API compatible changes)

Changelog

rusty_alloc

2.2.6 - 2026-10-09

Other

• (init) keep init.rs's CRLF line endings
• vein census 3 -- nine deterministic wins from real-program profiles

Performance

Measured against 2.2.5 with callgrind, allocator instructions, outputs
identical: Endless Sky start-up -6.85 %, lua -2.23 %, perl -1.64 %, sqlite
-0.11 %; Rust GlobalAlloc workloads up to -4.24 % whole-program. Peak RSS
within +-0.4 %. Details: docs/opps.md, "Vein census 3".

• Pages carve in growing batches. A page's first extension is still one
  4 KiB OS page; each later one carves as many blocks as the page already
  holds. Each extension costs a slow-path trip, and those trips, not the
  linking, were the cost. Thread start-up is unchanged.
• A cross-thread free into a full page goes straight to its owner (the
  free/operator delete exports test the owner first). Rust's dealloc
  keeps the 2.2.5 order, which keeps __rust_dealloc inlinable into drop
  glue. Trade-off: a same-thread free of a large or huge block costs 2 more
  instructions (about 1.4 % of that path).
• The slow path looks up a small size's bin from a table.
• operator new's slow path has a smaller frame (malloc_or_with, a
  typed OOM handler).
• A moving realloc resolves the block's page once, not twice.
• Exited threads' heap boxes are reused, saving an mmap/munmap pair
  and a page fault per thread.
• Rust: the natural-alignment arm of GlobalAlloc::alloc is out of line,
  and usable_size is inlinable.
• MSVC builds with panic = "unwind" take back one of the three
  instructions per free that 2.2.5's fix cost them.

Added

• alloc::malloc_or_with and the alloc::OnOom trait: malloc_or with the
  OOM handler as a type.
• alloc::free_inline_flags_first: free_inline's body in the 2.2.5 test
  order, for Rust's GlobalAlloc::dealloc.

rusty_alloc-api

2.2.6 - 2026-10-09

Other

• vein census 3 -- nine deterministic wins from real-program profiles

Performance

• GlobalAlloc::alloc moves its natural-alignment arm out of line, so the
  inlined method carries one malloc fast path, not two (maps -0.33 %,
  overaligned -1.81 %); over-aligned realloc inlines its usable-size
  query (-2.06 %); dealloc uses free_inline_flags_first. The core's
  changelog has the rest.

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