The v_exempt_secs parameter

Each time a suspended process is reactivated, it is exempt from suspension for a period of v_exempt_secs elapsed seconds. This ensures that the high cost in disk I/O of paging in the pages of a suspended process results in a reasonable opportunity for progress.

The default value of v_exempt_secs is 2 seconds.

# schedo -o v_exempt_secs=1

Suppose thrashing is caused occasionally by an application that uses lots of memory but runs for about T seconds. The default system setting of 2 seconds for the v_exempt_secs parameter probably causes this application swapping in and out T/2 times on a busy system. In this case, resetting the v_exempt_secs parameter to a longer time helps this application progress. System performance improves when this offending application is pushed through quickly.