One of the features google added to linux kernel is a general purpose allocator /dev/ion. The new allocator allows us to allocate memory from different heaps and devices, virtual and physical User space usage #include<stdio.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/mman.h> #include “/home/developer/kernel3.4/goldfish/include/linux/ion.h” void main() { int *p; struct ion_fd_data fd_data; […]
While configuring a Linux kernel, we can set some parameters that effect the system behavior. You can work with different priorities, scheduling classes and preemption models. It is very important to understand and choose the right parameters. In this post I will cover the different preemption models and how does each one effect the user and […]
On Android init phase we are running init application that uses its init scripts to start all the code system services. We can add a new daemon easily if we are building a ROM by add an empty folder, adding Android.mk file and C/C++ source file. In this way we can run C/C++ code but […]
Using cgroups you can limit resource usage of processes , for example if you have a web server and you want limit its memory usage to 1GB its very easy to do with cgroups. This is also a basic building block for containers First we need to install some tools (in my example im using […]
A network bridge helps you connect 2 different networks with the same characteristics (Ethernet for example). Its very easy to implement it in linux using some tools Example We run Qemu image with tap interface – we can connect from the qemu image to the linux host but we cant access the entire network (internet) […]