On Wed, Oct 10, 2018 at 5:09 AM Stephen J. Turnbull firstname.lastname@example.org wrote:
Chris Angelico writes:
Both processes are using the virtual memory. Either or both could be using physical memory. Assuming they haven't written to the pages (which is the case with executables - the system mmaps the binary into your memory space as read-only), and assuming that those pages are backed by physical memory, which process is using that memory?
One doesn't know. Clever side-channel attacks aside, I don't care, and I don't see how it could matter.
It matters a lot when you're trying to figure out what your system is doing.
Tell me, which process is responsible for libc being in memory? Other than, like, all of them?
Yes. Why would you want a different answer?
Because that would mean that I have way more *physical* memory in use than I actually have chips on the motherboard for.
No, that's like saying that because you have multiple links to a file on disk you're using more physical disk than you have.
Actually, that's exactly the same problem, with exactly the same consequences. How do you figure out why your disk is full? How do you enforce disk quotas? How can you get any sort of reasonable metrics about anything when the sum of everything vastly exceeds the actual usage?