Question

This answer to this question says that there’s no way to attach Valgrind to an already running process.
Are there any other tools for Linux that can report on memory usage but can attach to a process that’s already running?

Answer 1

You can use tools like pmap or ps_mem.py to get more details about the memory use of running processes than you get from top. You won’t get all the fancy features from Valgrind like detecting memory leaks and such.