Hi,

I have to implement a patch on the kernel that will enable users to limit I/O rate (this is a homework assignment). Basically, for every process and device we want to be able to set maximum average read/write rates (e.g. 5 KB/s). We may also want to implement a scheduling policy.

I've never done any kernel programming before, so I'd be grateful if anyone could give me links to relevant resources (how I/O operations are implemented on the kernel level, where should I make changes in the kernel, general stuff on how to modify the kernel etc.).

Start by actually using your GNU/Linux system. Recompile some vanilla kernels. Add a patch cleanly like Openwall (if you run 2.4) Dazuko, Sysmask, TOMOYO, IP personality. Read the kernel source code. Have different physical disks, run 'stress' and bonnie and play with schedulers. Use your favourite searchengine and simply search for "linux scheduler" and read docs that reference the "Understanding the Linux Kernel" book, search for "scheduling algorithms" and about anything on schedulers on the LKML. Learn how to code. Read kernel source code some more. Learn how to add your own driver to the kernel without making it OOPS. Get on the LKML and ask if any schedulers need improvement. Read the docs again. Discuss things on the LKML some more. Understand kernel source code. Submit your patch, get flamed, improve and resubmit. Arduous task at it may seem, time flies when you're having fun! So don't be surprised (in three measly years) to find you've already completed your assignment! (OK, provided you don't shower, live on only coffee and your head didn't explode already.)

Good luck.