The memory usage is calculated using the following formula in CloudMonitor:

(mem_total - (mem_free + mem_buffer + mem_cache)) /mem_total

You can run the cat /proc/meminfo command to check the usage of "mem_free", "mem_buffer", and "mem_cache". For example:

[Root @ localhost ~] # Cat proc/meminfo memtotal: 8011936 kbmemfree: 227336 kbbuffers: 277872 kbcached: 1451828 KB

Calculation method: (8011936-(227336 + 277872 + 1451828)/8011936

About 75.