Implementing Hazard Pointers in Rust
Channel: Jon Gjengset
Date: 2021-06-26

This time, we take a stab at implementing Hazard Pointers (https://erdani.org/publications/cuj-2004-12.pdf) in Rust. We follow along with the C++ implementation in Facebook's Folly library (https://github.com/facebook/folly/blob/master/folly/synchronization/Hazptr.h), as well as the C++ standardization proposal (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p1121r3.pdf).

0:00:00 Introduction
0:00:37 Rust for Rustaceans
0:01:00 Concurrent Memory Reclamation
0:10:32 Hazard Pointers
0:35:27 Folly's Hazard Pointer Interface
0:54:08 Delayed Reclamation
0:58:18 More Folly Interface
1:11:56 A Wild Entity Diagram Appears
1:16:40 Memory Use
1:21:12 More Folly Interface
1:27:50 Starting the Rust Code
1:35:24 Testing Out the Rust Interface
1:42:32 HazPtrHolder::load
2:02:15 HazPtrObject::retire
2:19:43 HazPtrHolder::reset
2:22:50 Unsafe Blocks in Unsafe Fns
2:25:04 Borrow Checker Prevents Misuse
2:27:45 Bad Drop Lint
2:34:15 Dropping in HazPtrDomain::retire
2:46:00 Intermission
2:47:57 Reading Folly's HazPtrDomain::retire
2:59:02 HazPtrDomain::acquire
3:17:32 HazPtrDomain::retire
3:45:57 Specifying a Deleter
4:32:26 Tests Pass?
4:36:12 Eager Reclaiming
4:37:32 Checking Reclamation Behavior
4:52:04 Final Thoughts

You can find the code for the implementation at https://github.com/jonhoo/haphazard.

Live version with chat: https://youtu.be/4PuE6oMYxeM