When I monitor my application using instruments and the instrument "allocations" I see a big amount of memory being marked as "dirty". What does that mean? I have no memory leaks in my application yet this pile of "dirty" memory keeps increasing.
Dirty is a computer term used to denote cached data that needs to be sync'ed with the main memory. Don't worry, since this is automatically done by the hardware.
"...I am trying to find out what is using up all my memory."
The WWDC 2010 Session 311 presentation, Advanced Memory Analysis with Instruments, includes a section on 'Responding to Memory Warnings' (at ~38:40 in the video) with a demo that illustrates how to find "resident, dirty memory" with the Instruments VM Tracker and one way to flush it.
来源：https://stackoverflow.com/questions/6443606/what-is-dirty-memory-in-instruments