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-<title>The Linux kernel in Debian - Ben Hutchings - DebConf 11</title>
+<title>The Linux kernel in Debian - Mini-DebConf Paris 2012</title>
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- <object class="logo" data="debconf11.svg"></object>
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<div id="footer">
-<h1>DebConf 11</h1>
+<h1>Mini-DebConf Paris 2012</h1>
<h2>The Linux kernel in Debian</h2>
</div>
<div class="slide">
<h1>The Linux kernel in Debian</h1>
<object data="tux-debian.svg" width="35%" align="right"></object>
-<h3>Ben Hutchings</h3>
+<h3>Ben Hutchings and Max Attems</h3>
</div>
<div class="slide">
- <h1>The author</h1>
- <ul class="incremental">
+ <h1>Ben Hutchings</h1>
+ <ul>
<li>
Professional software developer since 1998
</li>
</li>
<li>
Debian kernel contributor since 2008; uploader since 2009
- <ul class="incremental">
+ <ul>
<li>
Initially trying to deal with the non-free firmware issue
</li>
</ul>
</div>
+<div class="slide">
+ <h1>Max Attems</h1>
+ <ul>
+ <li>TODO</li>
+ </ul>
+</div>
+
<div class="slide">
<h1>Linux kernel</h1>
<ul class="incremental">
</div>
<div class="slide">
- <h1>Linux release model (1)</h1>
+ <h1>Linux release model</h1>
<p>
- The old model:
+ Since ~2004:
</p>
<ul class="incremental">
<li>
- Each stable release had even second component. Bug fixes and
- minor features in stable releases with third component
- incremented (e.g. 2.4.27)
+ Development results in a new stable(-ish) release every 2-3
+ months
+ <ul class="incremental">
+ <li>
+ git (and previously BitKeeper) made distributed development
+ and testing a lot easier
+ </li>
+ </ul>
</li>
<li>
- Major development done separately, resulting in series of
- unstable releases with odd second component (e.g. 2.5.50)
+ Each 2.6.<var>x</var> and 3.<var>x</var> release has a stable
+ update branch; releases numbered 2.6.<var>x</var>.<var>y</var>
+ and 3.<var>x</var>.<var>y</var>
+ <ul class="incremental">
+ <li>
+ Usually closed shortly after next stable release, but may
+ continue as a 'longterm' branch (e.g. 2.6.32.<var>y</var>)
+ </li>
+ </ul>
</li>
+ </ul>
+</div>
+
+<div class="slide">
+ <h1>Debian kernel team (1)</h1>
+ <p>
+ Who are we?
+ </p>
+ <ul class="incremental">
<li>
- After a year or two, development resulted in a new stable
- release
+ Currently 5 general maintainers: Maximilian Attems, Bastian
+ Blank, dann frazier, Ben Hutchings, Moritz Muehlenhoff
</li>
<li>
- Problem: users waited years for new features, and then got many
- more changes all at once. Particularly bad in the 2.4-2.6
- transition.
+ Many more specialised contributors:
+ <ul>
+ <li>Specific architectures</li>
+ <li>Specific features (e.g. Xen)</li>
+ <li>Bug triage</li>
+ </ul>
+ </li>
+ <li>
+ Would appreciate more help, particularly with bug triage and
+ PowerPC
</li>
</ul>
</div>
<div class="slide">
- <h1>Linux release model (2)</h1>
+ <h1>Debian kernel team (2)</h1>
<p>
- The new model:
+ What do we do?
</p>
<ul class="incremental">
<li>
- Development results in a new stable(-ish) release every 2-3
- months
- <ul class="incremental">
- <li>
- git (and previously BitKeeper) made distributed development
- and testing a lot easier
- </li>
- </ul>
+ Bug triage - takes a huge amount of time
</li>
<li>
- Each 2.6.<var>x</var> release has stable update branch; releases
- numbered 2.6.<var>x</var>.<var>y</var>
+ Backport bug fixes and features - particularly new hardware
+ support for stable
<ul class="incremental">
- <li>
- Usually closed shortly after next stable release, but may
- continue as a 'longterm' branch (e.g. 2.6.32.<var>y</var>)
- </li>
+ <li>...while trying not to change kernel ABI in stable</li>
</ul>
</li>
<li>
- Linux 3.0 doesn't change this, except that <var>x</var> is now
- the second component and <var>y</var> is the third
+ Update build configurations for each new upstream release -
+ e.g. to enable new drivers
+ </li>
+ <li>
+ Try to ensure smooth upgrades when there are major
+ implementation changes - e.g. KMS, switch to libata drivers
+ </li>
+ <li>
+ Integrate <em>some</em> features not accepted upstream
</li>
</ul>
</div>
<div class="slide">
- <h1>Debian kernel team</h1>
+ <h1>Official Linux kernel packages (1)</h1>
+ <p>
+ Main source package is <span class="package">linux</span>. Most
+ binary package names change regularly.
+ </p>
+ <ul class="incremental">
+ <li>
+ <span class="package">linux-image-<var>upstream</var>-<var>abi</var>-<var>flavour</var></span>
+ - compiled kernel and modules
+ </li>
+ <li>
+ <span class="package">linux-headers-<var>upstream</var>-<var>abi</var>-<var>flavour</var></span>
+ (and others) - development package for OOT modules
+ </li>
+ <li>
+ <span class="package">linux-libc-dev</span> - headers for userland
+ </li>
+ <li>
+ <span class="package">linux-source-<var>upstream</var></span> -
+ for custom kernels
+ </li>
+ <li>
+ <span class="package">linux-doc-<var>upstream</var></span>,
+ <span class="package">linux-manual-<var>upstream</var></span>, etc.
+ </li>
+ <li>
+ <span class="package">linux-support-<var>upstream</var>-<var>abi</var></span> -
+ scripts and metadata to support linux-latest
+ </li>
+ </ul>
</div>
<div class="slide">
- <h1>Official Linux kernel packages</h1>
+ <h1>Official Linux kernel packages (2)</h1>
+ <p>
+ The <span class="package">linux-latest</span> source package builds meta-packages
+ to support automatic upgrades between binaries built
+ from <span class="package">linux</span>.
+ </p>
+ <ul class="incremental">
+ <li>
+ <span class="package">linux-image-<var>flavour</var></span>
+ </li>
+ <li>
+ <span class="package">linux-headers-<var>flavour</var></span>
+ </li>
+ <li>
+ <span class="package">linux-source</span>,
+ <span class="package">linux-doc</span>,
+ <span class="package">linux-tools</span>, etc.
+ </li>
+ </ul>
+ <p class="incremental">
+ The installer will normally install
+ <span class="package">linux-image-<var>flavour</var></span> (for
+ some appropriate <var>flavour</var>).
+ </p>
</div>
<div class="slide">
- <h1>Custom Linux kernel packages</h1>
+ <h1>Official Linux kernel packages (3)</h1>
+ <ul class="incremental">
+ <li>
+ <span class="package">firmware-free</span> - separate 'firmware'
+ compliant with DFSG
+ </li>
+ <li>
+ <span class="package">linux-base</span> - base package for
+ images and tools
+ </li>
+ <li>
+ <span class="package">linux-tools</span> builds
+ <ul>
+ <li>
+ <span class="package">linux-kbuild-<var>upstream</var></span> -
+ kernel build system and tools for building OOT modules
+ </li>
+ <li>
+ <span class="package">linux-tools-<var>upstream</var></span>
+ - perf tool
+ </li>
+ <li>
+ <span class="package">usbip</span> - usbip configuration
+ tools
+ </li>
+ </ul>
+ </li>
+ </ul>
+</div>
+
+<div class="slide">
+ <h1>Custom Linux kernel builds</h1>
+ <p>
+ The official packages work for most users, but not all:
+ </p>
+ <ul class="incremental">
+ <li>
+ Different ARM platforms need incompatible configurations,
+ and we cannot build them all
+ </li>
+ <li>
+ New features are not enabled immediately if we are worried
+ about potential regressions
+ </li>
+ </ul>
+ <p class="incremental">
+ Using either upstream source or Debian linux-source package:
+ </p>
+ <ul class="incremental">
+ <li>
+ <span class="package">make && make install</span>
+ </li>
+ <li>
+ <span class="package">make deb-pkg</span> - build packages
+ </li>
+ <li>
+ <span class="package">make-kpkg</span> - build packages with
+ more customisation; requires
+ <span class="package">kernel-package</span>
+ </li>
+ </ul>
+</div>
+
+<div class="slide">
+ <h1>Extra features</h1>
+ <p>
+ Always aim to get patches merged upstream. But many big features
+ that users want added are <em>not</em> merged upstream for a long
+ time. Kernel team expects features to be upstream first, then
+ backported.
+ </p>
+ <p class="incremental">
+ But there have been exceptions:
+ </p>
+ <ul class="incremental">
+ <li>
+ OpenVZ and VServer - mostly reimplemented with cgroups and
+ namespaces
+ </li>
+ <li>
+ Xen - now upstream; Linux 3.0 is a useful dom0 kernel!
+ </li>
+ <li>
+ aufs - needed for Debian Live
+ </li>
+ <li>
+ PREEMPT_RT - gradually being merged upstream; new option in
+ amd64 packages
+ </li>
+ </ul>
</div>
<div class="slide">
<h1>Out-of-tree modules</h1>
+ <p>
+ The kernel team does not encourage the use of out-of-tree modules.
+ However, we support them by providing development packages and by
+ avoiding ABI changes during a stable release.
+ </p>
+ <p class="incremental">
+ Debian has two packages to aid in building out-of-tree modules:
+ </p>
+ <ul class="incremental">
+ <li>
+ <span class="package">dkms</span> - builds and installs modules
+ automatically. Can build packages for installation on other
+ systems. Also supported by Ubuntu and SUSE.
+ </li>
+ <li>
+ <span class="package">module-assistant</span> - builds packages
+ as directed. Uses a separate package name for each kernel ABI.
+ </li>
+ </ul>
</div>
<div class="slide">
<h1>Firmware files</h1>
+ <ul class="incremental">
+ <li>
+ Most peripherals have microcontroller running non-free
+ firmware; some require host to load it
+ </li>
+ <li>
+ Several drivers used to include firmware, making kernel
+ non-free. Fudged with GRs for a while; finally fixed in squeeze
+ </li>
+ <li>
+ Users with these devices - almost any wifi card, some network
+ controllers and Radeon GPUs - will still need the firmware
+ files installed
+ </li>
+ <li>
+ Kernel team maintains
+ <span class="package">firmware-nonfree</span> source package
+ covering most firmware files that are clearly redistributable
+ </li>
+ <li>
+ Also collected in linux-firmware.git repository maintained by
+ David Woodhouse and Ben Hutchings
+ </li>
+ </ul>
</div>
<div class="slide">
<h1>Documentation</h1>
+ <ul class="incremental">
+ <li>
+ <span class="package">manpages-dev</span> - the system call API
+ </li>
+ <li>
+ <span class="package">linux-doc-</span><var>upstream</var> -
+ miscellaneous upstream documentation
+ </li>
+ <li>
+ <span class="package">linux-manual-</span><var>upstream</var> -
+ the internal API, based on structured comments
+ </li>
+ <li>
+ <span class="package">debian-kernel-handbook</span> -
+ Debian-specific information; currently also Linux-specific but
+ could cover other kernels
+ </li>
+ <li>
+ <a href="http://wiki.debian.org/DebianKernel">http://wiki.debian.org/DebianKernel</a>
+ - wiki index page
+ </li>
+ </ul>
</div>
<div class="slide">
Redistribution is free but has to include this notice.
-->
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- <li>Modified by me to add Debian open-ND logo</li>
+ <li>Modified by Ben to add Debian open-ND logo</li>
</ul>
</li>
<li>
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-->
</li>
- <li>
- DebConf 11 logo © Aurélio A. Heckert.
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- <li>Resized and coloured by me</li>
- </ul>
- </li>
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