General :: Android Kernel Optimization

What sections of kernel code are changed for optimization of performance.

Like we can change
1) the minimum free memory that android need to keep free.
2) Rate of clearing cache
3)Advanced LMK- where we can kill more than one process at at time when memory scarcity occurs.
4) Reducing logging.
5) In framework we can change the oom_adj value of important processes.
6) Implement Zram for kernel.
7) change the minimum and maximum no of process for AMS.

I want to know all the changes that can be made into kernel or framework code to optimize performance. I also want to know how can we implement swapcache for android kernel. What changes do i need to make in the code.