Hazard pointer

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In a multithreaded computing environment, a hazard pointer is an element used by a methodology that allows the memory allocated to the nodes of lock-free dynamic shared objects to be reclaimed. Using the methodology, each thread keeps a list of hazard pointers indicating which nodes the thread may later access. This list can only be written to by the particular thread but can be read by any thread. When a thread wishes to remove a node, it places it on a private list and periodically scans the lists of all other threads for pointers referencing that node. If no such pointers are found the memory occupied by the node can be safely freed.

[edit] Reference

• Maged Michael (2004). "Hazard Pointers: Safe Memory Reclamation for Lock-Free Objects". IEEE Transactions on Parallel and Distributed Systems 15 (6): 491–504.