Other articles

1. Linux module dependencies

   With the imminent release of kmod 33, I thought it’d be good to have a post about the different types of module dependencies that we have in the Linux kernel and kmod. The new version adds another type, weak dependency, and as the name implies, is the weakest of all. But let’s revisit what are the other types first.

   
   

   Hard (symbol) dependency

   This is the first dependency that every appeared in kmod (and module-init-tools). A hard (or as some call, “symbol”) dependency occurs when your module calls or uses an exported symbol of another module. The most common …

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2. Optimizing hash table with kmod as testbed

   One thing that caught my interest lately was the implementation of hash tables, particularly the algorithms we are currently using for calculating the hash value. In kmod we use Paul Hsieh’s hash function, self entitled superfast hash. I fell troubled with anything that entitles itself as super fast, especially given the benchmarks provided are from some years ago, with older CPUs.

   After some time spent on benchmarking and researching I realized there were much more things to look after than just the hash function. With this post I try to summarize my findings, showing some numbers. However do take …

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3. Back from Linux Plumbers

   I’m back from USA after one week attending Linux Plumbers Conference. This was my first time in LPC, in which I was part of the CoreOS, talking about “From libabc to libkmod: writing core libraries”.

   It was a very good experience and I’m glad to meet so many developers, both kernel and userspace hackers. Some of them I only knew from IRC, mailing-lists, etc and it was great time to share our experiences, discuss the current problems in Linux and even fix bugs :-). We seem finally to have reached a consensus on how module signing should be done …

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4. ANNOUNCE: kmod 3

   Hey, kmod 3 is out. Really nice to finish this release. I was hoping to have it between the holidays, but there were some major bugs pending. It’s nice to see udev from git already using it instead of calling modprobe for each module. Kay reported a hundred less forks on bootup after start using libkmod and libblkid.

   It’s nice too receive feedback about other architectures that we don’t have access, too. With kmod 3, sh4 joined the other architectures that were tested with kmod.

   Since I’m already doing the announcements to the mailing lists, I …

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5. ANNOUNCE: kmod 2

   I’m glad to announce the second version of kmod.  I’m sorry for not sending the first version to the mailing lists. Now I’m both writing it here and sending to the mailing list.

   I thank very much the feedback received for the first version and that now Jon Masters, the maintainer of module-init-tools, is helping us with kmod and already announced that kmod will replace module-init-tools in future.

   I’d like to especially thank Tom Gundersen, Dave Reisner, Marco d’Itri, Jon Masters, Luis Strano, Jan Engelhardt and Kay Sievers who have been extensively testing kmod and …

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