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Busy-wait loop pattern

A Busy-wait loop pattern (often implemented as an infinite loop or spin loop) is a concurrency control mechanism where a thread repeatedly checks a condition within a loop, such as a for(;;) construct, until a specific state change or update is successfully processed^[600-developer-big-data-netty-netty-rotate.md].

Implementation

The pattern typically relies on a non-blocking structure where the thread continuously attempts to read and verify a shared variable (like a reference counter).^[600-developer-big-data-netty-netty-rotate.md]

In low-level or high-performance frameworks like [[Netty]], this is often implemented using atomic operations, such as AtomicIntegerFieldUpdater, to manage the state without locking the thread.^[600-developer-big-data-netty-netty-rotate.md] The loop continues to iterate—performing a read-calculate-check sequence—until an atomic conditional update (e.g., compareAndSet) succeeds, effectively handling the synchronization race condition.^[600-developer-big-data-netty-netty-rotate.md]

  • [[Atomic operations]]
  • [[Non-blocking algorithm]]
  • Spinlock

Sources

^[600-developer-big-data-netty-netty-rotate.md]