Instrument vm tracker dirty

I am using instrument "Alloc开发者_StackOverflowations" to monitor the app's memory. The vm tracker statistics puzzled me. Why there is so much dirty memory(for my app, reach 32M), I googled about this and knew that the dirty memory should be clear first when app received memory warning in background mode.

Could you tell me about the meaning of vm checker statistics? And how can I handle the dirties:VM_ALLOCATE, Core Animation.

Thanks in advance!

There is often very little you can do about VM usage directly; much of that will be due to use of various system APIs, etc...

Your time will be far more productively spent by focusing on the objects in the Allocations instrument itself and work towards both eliminating any leaks (accretion, too, not just leaks) and reducing allocation bandwidth.