KernelMaintenance

Revision 12 as of 2013-01-04 15:40:30

Howto for maintaining the linux-lowlatency kernel

The plan for maintaining kernels 12.04 and 12.10 is to keep the source at github, and have apw at UTK pull from there.

The plan for 13.04 is to use a PPA at launchpad (owned by ubuntustudio-kernel team)

Prerequisites

If doing maintenance from a ubuntu machine

sudo apt-get install ubuntu-dev-tools debhelper build-essential kernel-wedge kernel-package fakeroot
sudo apt-get build-dep linux-lowlatency

Maintain multiple releases using Linus tree as reference

Get the Source

Clone Linus main linux tree into a bare git reporitory.

git clone --bare git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linus-linux.git

Clone generic trees using Linus tree as reference (using apw trees as examples)

git clone --reference linus-linux.git git://kernel.ubuntu.com/ubuntu/ubuntu-precise.git ubuntu-precise-lowlatency
git clone --reference linus-linux.git git://kernel.ubuntu.com/ubuntu/ubuntu-quantal.git ubuntu-quantal-lowlatency
git clone --reference linus-linux.git git://kernel.ubuntu.com/ubuntu/ubuntu-raring.git ubuntu-raring-lowlatency

In each repo, add the lowlatency remote, and create a new branch for it (when basing on apw trees):

git remote add lowlatency git://kernel.ubuntu.com/apw/ubuntu-<release>-lowlatency.git
git fetch lowlatency
git checkout -b lowlatency lowlatency/lowlatency

You'll now have the main linux vanilla tree that Linus maintains, and three much smaller Ubuntu linux-generic trees (precise, quantal, raring), which share objects with the tree they refer to (linus-linux.git), each containing a branch for lowlatency.

Update Process

When a tracker bug appears, like this one: LP: #1095799, it is good time to prepare the linux-lowlatency source tree. (In this case, we are updating linux-lowlatency-precise)

First, make sure Linus vanilla tree is up to date.

~/repos/linus-linux.git$ git fetch

Now head to the lowlatency tree, and begin with cleanup (make sure we are in the lowlatency branch):

~/repos/ubuntu-precise-lowlatency$ git checkout lowlatency
~/repos/ubuntu-precise-lowlatency$ fakeroot debian/rules clean

Now, were going to do much of the maintenance procedure automatically, by using a script. Basically, it does a rebase against the generic kernel source, and does some nice looking git commits, as well as prepares the debian package for a new release version.