Thrashing is a high paging activity.A process is thrashing
if it is spending more time with paging rather than execution.
Caused by:-
* global replacement algorithm.
* under allocation of the minimum 
  number of pages required by a process.
* very high degree of multiprogramming.
Eliminated by:-
*reducing level or degree of multiprogramming.
*use local replacement algorithm.
*while allocating check minimum sufficient frame required
for   a process.