The thing is, that `sar -r` and `htop` report different statistics
about
kbmemfree if I understand right. Who will help me out of confusion,
please?

$ sar -r

13:30:01 kbmemfree kbmemused %memused kbbuffers kbcached
kbswpfree kbswpused %swpused kbswpcad
[...]
20:40:01 2200 512216 99.57 81024 196440
1001668 50548 4.80 21356
Average: 46549 467867 90.95 84552 162335
1012115 40101 3.81 10295

$ htop


CPU[|||
2.0%] Tasks: 109 total, 3 running

Mem[|||||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||||||||||||||||
228/502MB] Load average: 0.00 0.00 0.00

Swp[|||||
49/1027MB] Uptime: 1 day, 20:46:53

sar says 512.216 kilobytes kbmemused which accounts for 99.57%.
htop reports 228 megabytes Mem which is just 45.4%.

Both report fairly the same amount of total memory:

htop: 502 MB
sar : 46549 KB + 467867 KB = 514416 KB / 1024 = 502 MB

Now? What is the difference between kbmemused and htop statistics?

Thanks in advance
Michael.