Simple, Fast and Widely Applicable Concurrent Memory Reclamation via Neutralization
Bibliographic record
Abstract
Reclaiming memory in non-blocking dynamic data structures in unmanaged languages like C/C++ presents a unique challenge due to the risk of use-after-free errors caused by concurrent accesses. Existing safe memory reclamation (SMR) algorithms fall short of satisfying five key properties: high performance, bounded garbage, usability, consistency, and applicability. In particular, bounded garbage and high performance are quite difficult to achieve simultaneously. In this paper, we address this limitation by proposing a new, provably correct technique called neutralization based reclamation (NBR) that neutralizes threads using POSIX signals to provide the synchronization required for safe memory reclamation. NBR uses atomic reads and writes and achieves bounded garbage and high performance without imposing significant overhead on concurrent readers and writers. An extensive experimental evaluation serves to demonstrate the efficiency of our technique across various data structures, reclamation algorithms, and workloads. A detailed survey of popular concurrent data structures suggests NBR is applicable to a wide range of data structures, many of which could not be used with prior SMR algorithms that guarantee bounded garbage.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".