If a process does not have access to a sufficient number of memory pages, a futile, repetitive swapping condition known as "thrashing" often arises, and the page fault rate typically becomes high.
In virtual memory systems, thrashing may be caused by programs or workloads that present insufficient locality of reference: if the working set of a program or a workload cannot be effectively held within physical memory, then constant data swapping, i.e., thrashing, may occur.