It depends. The virtual memory would be normal, it would be better to provide vmstat values. The more important factor needs to monitor is Page-outs. It would be better to use vmstat to monitor your system and pay more attention to the "free", "si" and "so" values.
The free column shows the amount of free memory, si shows page-ins and so shows page-outs. In this example, the so column is zero consistently, indicating there are no page-outs.
BTW, there is something interesting on Linux, in terms of this case.
1. Linux uses a technique called "demand paging" where the virtual memory of a process is brought into physical memory only when a process attempts to use it. And it counts everyting, code, data and shared libs, in the virtual address space.
2. When the kernel detects that memory is running low, it attempts to free up memory by paging out. Though this may happen briefly from time to time, if page-outs are plentiful and constant, the kernel can reach a point where it's actually spending more time managing paging activity than running the applications, and system performance suffers. This woeful state is referred to as thrashing.
Correct me if I was wrong.
Thanks, KevinZ - NeoRouter team
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