Still confused why working set larger than virtual memory

[George2]

Hello everyone,


Sorry that this question is related to another question I posted some time before because I have some new findings and self-analysis.

My question is why sometimes from perfmon on Windows, working set larger than virtual memory? I think virtual memory is the total size of memory (committed, reserved, shared, private) and working set is just the RAM touched by current process currently. Virtual memory should always larger than working set...

But, I write a simple program to show working set is larger than virtual memory from perfmon. The program is simple, just open a couple of memory map files and read from beginning to the end.

The only reason I could think of why working set sometimes is larger than virtual memory is, the OS memory management component may not reclaim some RAM consumed by current process even if the current process does not use the RAM. And keeping such RAM could improve performance if the process will use it in the future. But this point makes me confused because I think if it is true, such RAM does not have related virtual memory address, how could the current process utilize or even address (re-use to avoid hard page fault) it in the future?


thanks in advance,
George