facebook/folly
Nov 2025 – May 2026
3 Months active
Languages Used
C++
Technical Skills
Linux kernel developmentmemory managementsystem programmingC++multithreadingC++ development
Devesh Agrawal
PROFILE
Devesh Agrawal
Worked on the facebook/folly repository, delivering core infrastructure for concurrent data structures and memory management in C++. Developed the ConcurrentBSkipList, introducing multi-key per-node storage and optimized hazard-pointer reclamation to improve throughput and cache locality under contention. Enhanced the hazptr API with a callable-source try_protect overload, simplifying safe memory reclamation. Addressed memory management by implementing Transparent Huge Page collapsing for efficient memory locking on Linux kernel 6.1+, reducing overhead in high-concurrency workloads. Fixed a shutdown crash in ThreadCachedArena by aligning memory allocation paths, improving stability during thread exit. Demonstrated expertise in C++, concurrency, Linux kernel development, and system programming.
Overall Statistics
Feature vs Bugs
67%Features
Repository Contributions
5Total
Bugs
1
Commits
5
Features
2
Lines of code
11,672
Activity Months3
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Work History
May 2026
3 Commits • 1 Features
May 1, 2026May 2026: Implemented ConcurrentBSkipList core with multi-key per-node storage, payload access optimizations, and hazard-pointer API enhancements; exposed RTIndex-focused payload hooks; introduced a callable-source hazptr try_protect overload. These efforts deliver a scalable, cache-friendly concurrent data structure with safer hazard-pointer reclamation and tighter integration with downstream indexing components, driving lower latency for scan-heavy workloads and higher insert/read throughput under contention.
3 Commits • 1 Features
May 1, 2026May 2026: Implemented ConcurrentBSkipList core with multi-key per-node storage, payload access optimizations, and hazard-pointer API enhancements; exposed RTIndex-focused payload hooks; introduced a callable-source hazptr try_protect overload. These efforts deliver a scalable, cache-friendly concurrent data structure with safer hazard-pointer reclamation and tighter integration with downstream indexing components, driving lower latency for scan-heavy workloads and higher insert/read throughput under contention.
May 2026
April 2026
1 Commits
Apr 1, 2026April 2026: Stabilized memory allocation paths in folly by delivering a ThreadCachedArena shutdown crash fix that aligns maxAlign across per-thread and zombies_ arenas. This prevents assertion failures during thread exit and reduces latent bug surface when non-default alignments are used (e.g., Unicorn’s NodeArena). Key work included code commit b6cf382dad1de1729c9e618d844332b5c39e5fd2 and differential D101491707, reviewed by luciang.
April 2026
1 Commits
Apr 1, 2026April 2026: Stabilized memory allocation paths in folly by delivering a ThreadCachedArena shutdown crash fix that aligns maxAlign across per-thread and zombies_ arenas. This prevents assertion failures during thread exit and reduces latent bug surface when non-default alignments are used (e.g., Unicorn’s NodeArena). Key work included code commit b6cf382dad1de1729c9e618d844332b5c39e5fd2 and differential D101491707, reviewed by luciang.
November 2025
1 Commits • 1 Features
Nov 1, 2025Month 2025-11: Key feature delivered: Efficient Memory Locking with THP Collapsing in folly, collapsing 4KB pages to a 2MB Transparent Huge Page (THP) before locking to optimize memory management and performance. Implemented via madvise with MADV_POPULATE_READ and MADV_COLLAPSE on Linux kernel 6.1+ and integrated with the existing chunked locking path in MemoryMapping. The change was landed with commit bec39c9eb3e9760f486e90e6a572a4047eb44218, reviewed by luciang, and tied to Differential Revision: D86993970. Major bugs fixed: none reported this month. This optimization reduces memory locking overhead and improves throughput under memory-intensive, high-concurrency workloads, demonstrating strong command of Linux memory management, performance tuning, and patch lifecycle.
1 Commits • 1 Features
Nov 1, 2025Month 2025-11: Key feature delivered: Efficient Memory Locking with THP Collapsing in folly, collapsing 4KB pages to a 2MB Transparent Huge Page (THP) before locking to optimize memory management and performance. Implemented via madvise with MADV_POPULATE_READ and MADV_COLLAPSE on Linux kernel 6.1+ and integrated with the existing chunked locking path in MemoryMapping. The change was landed with commit bec39c9eb3e9760f486e90e6a572a4047eb44218, reviewed by luciang, and tied to Differential Revision: D86993970. Major bugs fixed: none reported this month. This optimization reduces memory locking overhead and improves throughput under memory-intensive, high-concurrency workloads, demonstrating strong command of Linux memory management, performance tuning, and patch lifecycle.
November 2025
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Quality Metrics
Correctness96.0%
Maintainability80.0%
Architecture100.0%
Performance84.0%
AI Usage24.0%
Skills & Technologies
Programming Languages
C++
Technical Skills
C++C++ developmentConcurrencyLinux kernel developmentMemory managementalgorithm designconcurrent programmingdata structuresmemory managementmultithreadingsystem programming
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