Fig. 7 illustrates the classification process where two tasks,
JOB1 and JOB2, works together in SysMon. JOB1 is responsible
for collecting the number of hot pages. Its sampling
time interval is 3 s in our system and the sampling duration
in each interval is 10 ms (at most). Our experiments show
that 10 ms is enough to collect sufficient information and
incurs a negligible overhead. During each sampling JOB1
first clears __access_bit by the pte_mkold() kernel function,
and then collects the number of hot pages (__access_bit set to
1) at the end of the sampling. Note that hot page numbers