perf(allocator): Allocator::used_bytes do not use chunk iterator#21771
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graphite-app[bot] merged 1 commit intomainfrom Apr 26, 2026
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Merging this PR will degrade performance by 3.23%
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Pull request overview
This PR improves allocator accounting performance by adding Arena::used_bytes() and switching Allocator::used_bytes() to delegate to it, avoiding the ChunkRawIter iterator overhead.
Changes:
- Add
Arena::used_bytes()that computes total used bytes by walking chunk footers directly. - Re-implement
Allocator::used_bytes()as a thin inline(always) delegate toArena::used_bytes(). - Extend unit/quickcheck tests to validate
used_bytes()behavior alongsideallocated_bytes().
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Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.
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| File | Description |
|---|---|
| crates/oxc_allocator/src/arena/chunks.rs | Adds Arena::used_bytes() implementation that sums per-chunk used bytes without iterators. |
| crates/oxc_allocator/src/allocator.rs | Replaces iterator-based Allocator::used_bytes() with a delegated call to Arena::used_bytes(). |
| crates/oxc_allocator/src/arena/mod.rs | Updates ChunkFooter::cursor_ptr comment to include the new used_bytes usage. |
| crates/oxc_allocator/src/arena/tests.rs | Updates existing arena byte-counting test to assert used_bytes() at key points. |
| crates/oxc_allocator/tests/arena/quickchecks.rs | Adds quickcheck property test to validate used_bytes() tracking/invariants. |
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…21771) Add a method `Arena::used_bytes` which `Allocator::used_bytes` utilizes. Re-implement it to avoid using `ChunkRawIter` iterator, which is slightly more performant.
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Base automatically changed from
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April 26, 2026 22:01
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### 💥 BREAKING CHANGES - 502e804 ast: [**BREAKING**] Reduce size of `TSTypePredicateName` (#21711) (overlookmotel) - 5651539 ast: [**BREAKING**] Reduce size of `JSXExpression` (#21710) (overlookmotel) - c44e280 ast: [**BREAKING**] Reduce size of `ArrayExpressionElement` (#21709) (overlookmotel) - c5b3deb syntax: [**BREAKING**] Remove `CommentNodeId` (#21679) (overlookmotel) ### 🚀 Features - b738a39 allocator: Add `Allocator::cursor_ptr` method (#21773) (overlookmotel) - 678767e ast: Generate node_id accessors for AST enum wrappers (#21653) (camc314) - f091d77 minifier: Inline constant spread elements into arrays (#21095) (Armano) ### 🐛 Bug Fixes - 0d608c2 minifier: Preserve raw CR in template literals (#21645) (Dunqing) - a889ea9 minifier: Track pure functions in DCE mode (#21722) (Dunqing) - 674dfac allocator: `Arena` retry allocation when chunk size approaches maximum (#21777) (overlookmotel) - f130cc0 allocator: Fix arithmetic overflow in `Arena::new_chunk_memory_details` (#21745) (overlookmotel) - b9bf239 allocator: Fix UB in `Arena::grow_zeroed` (#21739) (overlookmotel) - d2b9389 allocator: Clippy warning when building without `testing` feature (#21681) (camc314) - 503dc86 codegen: Map sourcemaps from visible output starts (#21662) (Dunqing) - c92bd3b transformer: Use SPAN for synthesized helper calls to prevent comment misattribution (#21578) (Dunqing) - 0d80441 codegen: Add mapping before printing `#` for private ident (#21619) (camc314) ### ⚡ Performance - 9fa362e napi/parser: Do not generate tokens except in tests (#21811) (overlookmotel) - 0044392 allocator: Reduce branches when allocating new chunk (#21776) (overlookmotel) - 7896bd0 allocator: `Allocator::used_bytes` do not use chunk iterator (#21771) (overlookmotel) - a5c562f allocator: Remove check in `Arena::new_chunk_memory_details` (#21750) (overlookmotel) - 35bbe1f allocator: `Arena` use unchecked size round up where guaranteed no overflow (#21743) (overlookmotel) - ffe229b allocator: Remove unnecessary check from `Arena::try_alloc_layout_slow_impl` (#21732) (overlookmotel) - 72fece5 allocator: Use `NonNull::offset_from_unsigned` in `Arena::chunk_capacity` (#21731) (overlookmotel) - cab32ae ast: Add `#[inline(always)]` to `node_id` methods on enums with all variants unboxed (#21707) (overlookmotel) - b179688 parser: Allocate `TriviaBuilder` comments in the arena (#21512) (Boshen) - 2290f31 lexer: Fix perf of `Token::set_*` methods on Rust 1.95.0 (#21659) (overlookmotel) - 1b58029 allocator: Move code into cold path in `Arena::alloc_layout` (#21622) (overlookmotel) - 3cf7cef allocator: Reduce instructions on allocation hot path (#21510) (overlookmotel) ### 📚 Documentation - ce65070 data_structures: Document why `as_ref` and `as_mut` on `NonNullConst` and `NonNullMut` take `self` (#21800) (overlookmotel) - 93b7dbd allocator: Improve doc comments for `ChunkFooter` (#21733) (overlookmotel) - 295db8d transformer: Fix comment (#21717) (overlookmotel) - 5c93af8 ast: Add comments explaining `#[inline(always)]` to `node_id` methods on enums (#21706) (overlookmotel) - e4cea25 transform: Use the `node:` namespace in the example (#19998) (루밀LuMir) ### 🛡️ Security - d8076c9 deps: Update rolldown (#21639) (renovate) Co-authored-by: Boshen <1430279+Boshen@users.noreply.github.com>
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Add a method
Arena::used_byteswhichAllocator::used_bytesutilizes. Re-implement it to avoid usingChunkRawIteriterator, which is slightly more performant.