Memory usage monitor percentage issue

[CAQ]

3.5.1 version, legacy frontend memory usage monitor,
transferred data (browser F12):
{
"self": 122669016,
"server_avail": 126167092,
"server_total": 129780432,
"unit": "KB"
}

Displayed:
图数据库使用 116.87GB
可用 120.32GB
其他 -113.43GB
使用率 94.4%

should not be negative value.

// Another server, not repeated (0.11GB, 1.34GB, 0.5GB, 5.6% respectively)