A simple tool/script to collect swap related information.

Example usage:
	./fiostat.sh -o xxx

Some options for fiostat.sh:
-l	lock memory. If swap is heavy, memory used by application can be
	reclaimed. This makes sure it will not happen in this tool. This
	option is disabled by default.
-d	interval between samplings. The unit is second. If this option isn't
	enabled, the sampling interval is 1 second.
-c	sampling duration. If this option isn't enabled, the tool will sampling
	forever until it's killed.
-o	output directory.