låsestruktur

Låsestruktur is a concept in computer science that refers to the design and organization of locking mechanisms used to control access to shared resources in concurrent systems. The purpose is to prevent data corruption, maintain isolation between operations, and coordinate access among competing processes or threads.

Key concepts include lock granularity, which ranges from coarse-grained locks that cover large resources to fine-grained locks that protect smaller items. Lock types commonly include shared (read) locks and exclusive (write) locks, with some systems also using intent locks to indicate planned modes at higher levels. Compatibility rules determine which locks can be held together, and many systems use protocols such as two-phase locking to ensure a degree of serializability, at the cost of potential deadlocks.

Deadlocks are a central concern in låsestruktur. Prevention and detection strategies include enforcing a global lock ordering, using timeouts, or employing deadlock detectors. Lock escalation, where many fine-grained locks are consolidated into a single coarse-grained lock, is another technique to balance performance and resource use.

Låsestruktur is implemented across various domains. In databases, locks can be at row, page, or table level to balance concurrency and overhead. In file systems and operating systems, mutexes, semaphores, and spinlocks protect critical sections. In programming languages, locking primitives such as mutexes or monitors provide higher-level synchronization.

Understanding låsestruktur involves balancing contention and overhead, choosing appropriate granularity, and designing for predictable performance in high-concurrency environments. See also concurrency control, transaction isolation, and deadlock management.