気になること

Mac

ふと、sshでログインし、topしたら

Processes: 51 total, 3 running, 48 sleeping... 120 threads 07:52:33
Load Avg: 1.41, 1.39, 1.33 CPU usage: 86.6% user, 10.7% sys, 2.7% idle
SharedLibs: num = 98, resident = 23.9M code, 1.62M data, 7.67M LinkEdit
MemRegions: num = 3113, resident = 32.6M + 7.53M private, 61.9M shared
PhysMem: 117M wired, 163M active, 986M inactive, 1.24G used, 15.3M free
VM: 2.64G + 62.7M 9557(0) pageins, 938(0) pageouts

最後の、15.3M Free って、どういうこと？