C++。 如何在 linux 中跟踪 memory 分配给.so 模块

Question

We are in a situation that have a large application and now there is a situation that would need to know which.so module is allocating how much memory. I have no idea here, I was wondering a custom allocator overriding operator new, but that didn't help because I still cannot trace which module is doing to allocation. Replacing new by custom allocator would be terrible amount of work. Does anyone know how can I tell which module is doing how much allocations?

Answer 1

It's not easy.

You can hook malloc , free , realloc globally in the application. Corresponding articles on Stackoverflow: How to use __malloc_hook? , An alternative for the deprecated __malloc_hook functionality of glibc .

You can retrieve a caller address from that hooks using __builtin_return_address and compare it with addresses of shared libraries. Maybe you have to examine a deeper frame address to get a proper address in a library, not an address of libc++. Read this Stackoverflow article __builtin_return_address returns null for index >0? .

Answer 2

You could make use of the LD_PRELOAD trick to hook malloc , realloc , free etc. That, combined with the info gleaned from boost.stacktrace would get you most (if not all) of what you need. Not trivial though.