在Linux程序中跟踪活动使用的内存

I'd like to track how much memory various programs touch while in specific states. For instance, say I have a graphical program. It might use substantially less memory when it's minimized, since it won't redraw the window, which requires reading images and fonts and executing a large number of library functions. These objects are still accessible in memory, but they aren't actually being used. I'd like to track how much memory various progr