Actually, the libc is dynamically linked here, as shown in the /proc/maps section of the article. So, to answer the GP: yes, resident memory from the libc ends

Actually, the libc is dynamically linked here, as shown in the /proc/maps section of the article. So, to answer the GP: yes, resident memory from the libc ends up being amortized between all the processes that use it. But it doesn't even matter much as there's a mere 5 MiB of resident memory involved here. The “hundreds of MiB” are only of virtual memory, and that shouldn't be of any concern (see my other comment in this thread).