Thrashing

Consider that the maximum number of frames assigned to a process is fixed.

If this number is always greater or equal to the number of pages of the different working sets of the process:

• the process’s life will be a succession of periods with frequent page faults with periods almost without them.

If it is lower.

• the process will be continuously generating page faults.

• in such cases, it is said to be in thrashing.

Keeping the working set of a process always in memory is a page replacement design challenge.