Kernel Hacker Keith Owens On kbuild 2.5, XFS, More

Jeremy Andrews writes: "Kerneltrap interviews Keith Owens this week, an experienced kernel hacker who has long contributed to the Linux kernel. His contributions include updating ksymoops and modutils, both of which he maintains. He also works on kbuild 2.5. Earlier, he built the original Integrated Kernel Debugging patch. He's also working on kdb and XFS. Check out the interview." Lots of good information in here about things to expect in 2.5.

Comments

Global Makefile!

[swillden]

From the interview:

...kbuild 2.5 builds a global Makefile from Makefile.in fragments in each directory then compiles and links only the sections of code that absolutely need to be recompiled

This is excellent, and I hope more open source projects start to go this way. It's been known for a while that recursive make is a bad idea because it's inaccurate. Naive recursive makefile structures tend to miss stuff that needs to be built/installed and fixing that problem (usually with ugly hacks like make dep) generally results in building stuff that doesn't need to be built.

What Keith describes is a nice solution that provides the benefits of recursive make without the problems: Use per-directory makefile fragments which can be maintained locally, but automatically generate a complete, tree-wide makefile that is actually used for the build.

There are tools other than make that provide more elegant solutions, but given that they never seem to catch on, I'm happy to see that someone is applying the tool we have (make) correctly, for once.

I'm looking forward to this one.