Definition
Thrashing
Thrashing occurs when a processor spends disproportionate time handling page faults versus executing instructions, causing drastic performance drops.
Mechanism
Feedback Loop
Occurs when sum of resident sets exceeds available RAM. The replacement policy swaps out pages needed almost immediately, creating a cycle: page swapped in → another fault → first page swapped out.
Causes
Insufficient RAM
Physical memory too small for current workload.
Poor Locality
Process accesses memory in scattered patterns unsuitable for paging.
Over-multiprogramming
Too many active processes squeezing resident sets below their working sets.
Prevention
Working Set Management
Monitor pages each process needs and ensure they remain resident.
Process Suspension
Temporarily suspend processes to free frames for remaining active ones.