diff options
Diffstat (limited to 'kernel-devel')
| -rw-r--r-- | kernel-devel/kernel-basics/pres_kernel-basics_de.tex | 263 | ||||
| -rw-r--r-- | kernel-devel/kernel-best-practices/handout_kernel-best-practices_en.tex | 498 |
2 files changed, 761 insertions, 0 deletions
diff --git a/kernel-devel/kernel-basics/pres_kernel-basics_de.tex b/kernel-devel/kernel-basics/pres_kernel-basics_de.tex index 372ada2..1cfb985 100644 --- a/kernel-devel/kernel-basics/pres_kernel-basics_de.tex +++ b/kernel-devel/kernel-basics/pres_kernel-basics_de.tex @@ -56,6 +56,61 @@ \end{itemize} \end{frame} +\begin{frame} +\includegraphics[height=7cm]{images/linus7.jpg} + +Maintains: THE REST + +Company: linuxfoundation +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/alan.png} + +Credits: NET2Debugged/NET3 author, Network layer debugging, Initial AX.25 and +IPX releases, Original Linux netatalk patches, Current 3c501 hacker, Watchdog +timer drivers, Linux/SMP + +Company: intel +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/morton.jpg} + +Maintains: EXT3, JOURNALLING LAYER FOR BLOCK DEVICES (JBD) + +Credits: Linux Quality Management + +Company: Google +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/greg.jpg} + +Maintains: SERIAL DRIVER, DRIVER CORE, KOBJECTS, DEBUGFS AND SYSFS, STABLE +BRANCH, STAGING SUBSYSTEM, TTY LAYER, USB SERIAL DRIVER, USB SUBSYSTEM, +USERSPACE I/O + +Company: SuSE +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/hch.jpg} + +Maintains: FREEVXFS FILESYSTEM, PERSONALITY HANDLING, SYSV FILESYSTEM, XFS +FILESYSTEM +Company: ?? +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/tglx.jpg} + +Maintains: HIGH-RESOLUTION TIMERS, CLOCKEVENTS, DYNTICKS, POSIX CLOCKS and +TIMERS, X86 ARCHITECTURE (32-BIT AND 64-BIT), PREEMPT RT + +Company: linutronix +\end{frame} + \subsubsection{Entwicklungsprozess} \begin{frame} \frametitle{Entwicklungsprozess} @@ -63,13 +118,221 @@ \item Änderungsvorschläge in Form von Patchen \pause \item Review und Diskussion auf Mailinglisten +\item z.B. Subsystem Mailinglisten und LKML \pause \item strenge Richtlinien für Coding Style +\item siehe Documentation/CodingStyle im Kernel Source Tree \pause \item strenge Richtlinien für Form und Weitergabe von Patchen +\item scripts/checkpatch.pl zur Kontrolle verwenden! \pause \item Nur technische Argumente zählen! +\pause +\item Dokumentation siehe MAINTAINER Datei im Kernel Source Tree +\end{itemize} +\end{frame} + +\subsubsection{Versionierung} +\begin{frame} +\frametitle{Versionierung} +\begin{itemize} +\item 2.6.38.1 oder 2.6.39-rc1 +\pause +\item 2.6 - historisch gegeben (aus altem Schema) +\pause +\item .38 - aktuelle Version +\pause +\item .1 - Security Fix +\pause +\item .rc1 - Release Candidate +\end{itemize} +\end{frame} + +\subsubsection{Entwicklungstempo} +\begin{frame} +\frametitle{Entwicklungstempo} +\begin{itemize} +\item 2 \dots 3 months release cycle +\item \dots about 10,000 patches each cycle +\item \dots from over 1000 developers +\item \dots about 200 companies +\end{itemize} +Quelle: http://www.linuxfoundation.org/docs/lf\_linux\_kernel\_development\_2010.pdf +\end{frame} + +\begin{frame} +\includegraphics[height=7cm]{images/linux-found-devel-cycle.png} + +Source: Linux Foundation +\end{frame} + +\begin{frame} +\includegraphics[height=6.5cm]{images/linux-found-changes-version.png} +\begin{tabular}{ l | l| } +2.6.25 & 12,243 \\ +2.6.26 & 9,941 \\ +2.6.27 & 10,628 \\ +2.6.28 & 9,048 \\ +2.6.29 & 11,678 \\ +2.6.30 & 11,989 \\ +2.6.31 & 10,883 \\ +2.6.32 & 10,989 \\ +2.6.33 & 10,871 \\ +2.6.34 & 9,443 \\ +2.6.35 & 9,801 \\ +\end{tabular} + +Source: Linux Foundation +\end{frame} + +\begin{frame} +\includegraphics[height=6.5cm]{images/linux-found-changes-hour.png} +\begin{tabular}{ l | l| } +2.6.25 & 6.15 \\ +2.6.26 & 4.71 \\ +2.6.27 & 5.03 \\ +2.6.28 & 4.96 \\ +2.6.29 & 5.47 \\ +2.6.30 & 6.40 \\ +2.6.31 & 4.93 \\ +2.6.32 & 5.46 \\ +2.6.33 & 5.39 \\ +2.6.34 & 4.86 \\ +2.6.35 & 5.30 \\ +\end{tabular} + +Source: Linux Foundation +\end{frame} + +\begin{frame} +\frametitle{Kernel size} +\begin{tabular}{ l | l | r } +Version & Files & Lines \\ +\hline +2.6.11 & 17,090 & 6,624,076 \\ +2.6.13 & 18,090 & 6,988,800 \\ +2.6.15 & 18,811 & 7,290,070 \\ +2.6.17 & 19,553 & 7,588,014 \\ +2.6.19 & 20,936 & 7,976,221 \\ +2.6.21 & 21,614 & 8,246,517 \\ +2.6.23 & 22,530 & 8,566,606 \\ +2.6.25 & 23,813 & 9,232,592 \\ +2.6.27 & 24,356 & 9,630,074 \\ +2.6.29 & 26,702 & 10,934,554 \\ +2.6.31 & 29,143 & 11,970,124 \\ +2.6.33 & 31,584 & 12,912,684 \\ +2.6.35 & 33,335 & 13,468,253 \\ +\end{tabular} + +Source: Linux Foundation +\end{frame} + +\begin{frame} +\frametitle{Kernel lines per day} +\begin{tabular}{ l | r | l | r } +Version & Added & Deleted & Modified \\ +\hline +2.6.11 & 3,224 & 1,360 & 1,290 \\ +2.6.13 & 4,443 & 1,553 & 1,711 \\ +2.6.15 & 5,614 & 3,454 & 2,219 \\ +2.6.17 & 3,635 & 2,469 & 1,329 \\ +2.6.19 & 6,013 & 2,900 & 1,862 \\ +2.6.21 & 3,256 & 1,479 & 982 \\ +2.6.23 & 3,747 & 3,034 & 1,343 \\ +2.6.25 & 7,980 & 3,488 & 2,430 \\ +2.6.27 & 12,270 & 9,791 & 2,102 \\ +2.6.29 & 14,678 & 5,516 & 2,454 \\ +2.6.31 & 9,408 & 4,962 & 1,635 \\ +2.6.33 & 8,925 & 4,379 & 2,841 \\ +2.6.35 & 7,896 & 5,037 & 1,802 \\ +\end{tabular} + +Source: Linux Foundation +\end{frame} + +\begin{frame} +\frametitle{Linux Companies} +contribution between 2.6.11 and 2.6.35 +\begin{tabular}{ l | r | r } +Company & Changes & Percent of Total \\ +\hline +None & 35,663 & 18.9 \\ +Red Hat & 23,356 & 12.4 \\ +Novell & 13,120 & 7.0 \\ +IBM & 13,026 & 6.9 \\ +Unknown & 12,060 & 6.4 \\ +Intel & 11,028 & 5.8 \\ +consultants & 4,817 & 2.6 \\ +Oracle & 4,367 & 2.3 \\ +Renesas Technology & 2,621 & 1.4 \\ +The Linux Foundation & 2,488 & 1.3 \\ +academics & 2,464 & 1.3 \\ +SGI & 2,450 & 1.3 \\ +Fujitsu & 2,293 & 1.2 \\ +Parallels & 2,226 & 1.2 \\ +Analog Devices & 1,955 & 1.0 \\ +Nokia & 1,896 & 1.0 \\ +\end{tabular} +\end{frame} + +\begin{frame} +\frametitle{Linux Companies (cont.)} +contribution between 2.6.11 and 2.6.35 +\begin{tabular}{ l | r | r } +Company & Changes & Percent of Total \\ +\hline +HP & 1,854 & 1.0 \\ +MontaVista & 1,821 & 1.0 \\ +Google & 1,565 & 0.8 \\ +AMD & 1,518 & 0.8 \\ +Freescale & 1,501 & 0.8 \\ +linutronix & 1,470 & 0.8 \\ +MIPS Technologies & 1,410 & 0.7 \\ +NetApp & 1,322 & 0.7 \\ +Marvell & 1,241 & 0.7 \\ +Atheros Communications & 1,234 & 0.7 \\ +Astaro & 1,222 & 0.6 \\ +Broadcom & 1,130 & 0.6 \\ +QLogic & 1,076 & 0.6 \\ +NTT & 1,068 & 0.6 \\ +\end{tabular} + +Source: Linux Foundation +\end{frame} + +\subsubsection{staging und next} +\begin{frame} +\frametitle{staging} +\begin{itemize} +\item Verzeichnis im Kernelsourcetree +\pause +\item erm\"oglicht Entwicklung im Mainline Tree +\pause +\item enth\"alt haupts\"achlich Treiber +\pause +\item Voraussetzung: aktive Weiterentwicklung im Code +\end{itemize} +\end{frame} + +\begin{frame}[fragile] +\frametitle{next} +\begin{itemize} +\item \"Anderungen welche vermutlich in die n\"achste Version aufgenommen +werden +\item tracked andere Trees und quilt queues \end{itemize} +\begin{lstlisting} +Feb-2008, Stephen Rothwell: +I hope to recreate this tree every day automatically. +In order to do this, any tree that has a conflict will +be dropped from that days tree. +The maintainer will be notified. I hope to provide some +clue as to what the conflict is with, but probably not +initially. I will attempt to build the tree between each +merge (and a failed build will again cause the offending +tree to be dropped). These builds will be necessarily +restricted to probably one architecture/config. +\end{lstlisting} \end{frame} \subsubsection{Konfiguration} diff --git a/kernel-devel/kernel-best-practices/handout_kernel-best-practices_en.tex b/kernel-devel/kernel-best-practices/handout_kernel-best-practices_en.tex new file mode 100644 index 0000000..bd1140b --- /dev/null +++ b/kernel-devel/kernel-best-practices/handout_kernel-best-practices_en.tex @@ -0,0 +1,498 @@ +\input{confighandout} + +\subsection{Kernel Best-Practices} + +Linux development is heavily distributed. There are many powerful tools, which +assist the distributed development. The most important and powerful ones, will +be presented in this chapter. + +\subsubsection{diff and patch - the basics} + +Linux kernel development is based on patches. A patch is a file which describes +the changes between an original version of a source tree and a modified one. + +For simplicity, a source tree with only one file will be used as example: + +orig/hello.c + +\begin{lstlisting} +int main (int argc, char **argv) +{ + return 0; +} +\end{lstlisting} + +This source tree will be copied: + +\begin{lstlisting} +cp -a orig new +\end{lstlisting} + +The new source tree be modified: + +new/hello.c + +\begin{lstlisting} +#include <stdio.h> + +int main (int argc, char **argv) +{ + printf ("Huhu World\n"); + return 0; +} +\end{lstlisting} + +The diff commands generates a patch file: + +\begin{lstlisting} +diff -Nur orig new > hello.patch +\end{lstlisting} + +The content of hello.patch is: + +\begin{lstlisting} +--- orig/hello.c 2011-03-22 22:38:40.796426752 +0100 ++++ new/hello.c 2011-03-22 22:39:02.472155769 +0100 +@@ -1,4 +1,7 @@ ++#include <stdio.h> ++ + int main (int argc, char **argv) + { ++ printf ("Huhu World\n"); + return 0; + } +\end{lstlisting} + +The newly added lines are prefixed with a '+', removed lines with a '-'. + +If the patch file is more complex, diffstat informs you about the content: + +\begin{lstlisting} +diffstat hello.patch + hello.c | 3 +++ + 1 file changed, 3 insertions(+) +\end{lstlisting} + +Anyone who has the original source version, can apply the generated patch. The +result is an updated version of the source tree: + +\begin{lstlisting} +cd orig +patch -p1 < ../hello.patch +\end{lstlisting} + +With the argument -pX the numbers of stripped directories (in our case new) can be defined. + +With the argument -R a patch can be 'reverse applied' aka removed. The result +will be the original source tree. + +Don't apply or remove the same patch more then once. If you have more than one +patch, apply and revert the patches in the right order. Else the resulting +source tree will be undefined. + +If the original source differs from the one, the patch was created. The patch +may apply with 'HUNKS'. This means, the changes can be applied, but the line +numbers, given after the @@@ tag don't fit exactly. + +If the original source differs from the one, the patch was created. It is +possible, that the patch won't apply anymore. Then all rejects are saved in a +file called <original file name>.rej + +\subsubsection{quilt} + +diff and patch work fine for one patch. But if you have to handle a queuqe of +patches it will be hard to keep the order of the patches, update a single patch,etc. quilt is a tool, for managing patch queques. + +The above example, using quilt: + +orig/hello.c + +\begin{lstlisting} +int main (int argc, char **argv) +{ + return 0; +} +\end{lstlisting} + +create a new patch: + +\begin{lstlisting} +cd orig +quilt new hello.patch +quilt edit hello.c +\end{lstlisting} + +your default editor will be opened, make your changes to the source: + +\begin{lstlisting} +#include <stdio.h> + +int main (int argc, char **argv) +{ + printf ("Huhu World\n"); + return 0; +} +\end{lstlisting} + +write the changes into the patch file: + +\begin{lstlisting} +quilt refresh +\end{lstlisting} + +two files will be generated: + +\begin{lstlisting} +ls patches/ +hello.patch series +\end{lstlisting} + +hello.patch is our well-known patch. series contains the name of our patch. + +The patch can be applied + +\begin{lstlisting} +quilt push +File series fully applied, ends at patch patches/hello.patch +\end{lstlisting} + +Then we create a new patch on top of our current queque: + +\begin{lstlisting} +quilt new seperate-print-in-own-function.patch +quilt edit hello.c +\end{lstlisting} + +\begin{lstlisting} +#include <stdio.h> + +void print () +{ + printf ("Huhu World\n"); +} + +int main (int argc, char **argv) +{ + print (); + return 0; +} +\end{lstlisting} + +both patches are now listed in the series file: + +\begin{lstlisting} +cat patches/series +hello.patch +seperate-print-in-own-function.patch +\end{lstlisting} + +All patches can be reverted at once: + +\begin{lstlisting} +quilt pop -a +Removing patch patches/seperate-print-in-own-function.patch +Restoring hello.c + +Removing patch patches/hello.patch +Restoring hello.c + +No patches applied +\end{lstlisting} + +You can zip the quilt queque and share it with other programmers. + +\subsubsection{git} + +But if they modify the quilt queque at the same time, as you. Merging the +queques by hand may be hard. In projects like the linux kernel, it is a no go. + +Currently Linus' (and many others) Kernel trees are managed by git. Git is a +very powerful version control system. The most important difference to other +systems, like subversion, is that the hole history of a project is held local. +Nobody should commit into your git tree. In git you pull the changes from other +people into your tree. + +Let's have a look at git: + +orig/hello.c + +\begin{lstlisting} +int main (int argc, char **argv) +{ + return 0; +} +\end{lstlisting} + +init git: + +\begin{lstlisting} +$cd orig +$git init . +Initialized empty Git repository in /home/manut/vorlesung.git/orig/.git/ +$git config user.email "manut@mecka.net" +$git config user.name "Manuel Traut" +\end{lstlisting} + +The configuration is saved at .git/config +If git config --global is used the configuration will be used by all +repositories which don't have a own configuration. Then it is saved at +~/.gitconfig + +Now add the files to version control and commit your initial code. + +\begin{lstlisting} +$git add hello.c +$git commit -sa +\end{lstlisting} + +The default editor will be opened, to enter a commit message: + +\begin{lstlisting} +initial import of the hello world source + +this projects is aimed to show the use of git. + +Signed-off-by: Manuel Traut <manut@mecka.net> + +# Please enter the commit message for your changes. Lines starting +# with '#' will be ignored, and an empty message aborts the commit. +# On branch master +# +# Initial commit +# +# Changes to be committed: +# (use "git rm --cached <file>..." to unstage) +# +# new file: hello.c +# + +[master (root-commit) 473cf10] initial import of the hello world source + 1 files changed, 4 insertions(+), 0 deletions(-) + create mode 100644 hello.c + +\end{lstlisting} + +Now edit the source tree and generate commit your changes: + +\begin{lstlisting} +$patch -p1 < ../hello.patch +$git commit -sa + +add stdio include, print hello world + +prints 'Huhu World' to stdout + +Signed-off-by: Manuel Traut <manut@mecka.net> + +# Please enter the commit message for your changes. Lines starting +# with '#' will be ignored, and an empty message aborts the commit. +# On branch master +# Changes to be committed: +# (use "git reset HEAD <file>..." to unstage) +# +# modified: hello.c + +[master 6ea27e6] add stdio include, print hello world + 1 files changed, 3 insertions(+), 0 deletions(-) + +\end{lstlisting} + +A hash will be generated that can be used to identify each patch. A history +and a single patch can be displayed with these commands: + +\begin{lstlisting} +$git log +commit 6ea27e6199aeac63055d845ef40fecd4b594f1d7 +Author: Manuel Traut <manut@mecka.net> +Date: Tue Mar 22 23:37:13 2011 +0100 + + add stdio include, print hello world + + prints 'Huhu World' to stdout + + Signed-off-by: Manuel Traut <manut@mecka.net> + +commit 473cf10e95778c54d49fc6ea368e196f1347ac8a +Author: Manuel Traut <manut@mecka.net> +Date: Tue Mar 22 23:31:50 2011 +0100 + + initial import of the hello world source + + this projects is aimed to show the use of git. + + Signed-off-by: Manuel Traut <manut@mecka.net> + + +$git shortlog +Manuel Traut (2): + initial import of the hello world source + add stdio include, print hello world + +$git show 473cf10e95778c54d49fc6ea368e196f1347ac8a +commit 473cf10e95778c54d49fc6ea368e196f1347ac8a +Author: Manuel Traut <manut@mecka.net> +Date: Tue Mar 22 23:31:50 2011 +0100 + + initial import of the hello world source + + this projects is aimed to show the use of git. + + Signed-off-by: Manuel Traut <manut@mecka.net> + +diff --git a/hello.c b/hello.c +new file mode 100644 +index 0000000..b891504 +--- /dev/null ++++ b/hello.c +@@ -0,0 +1,4 @@ ++int main (int argc, char **argv) ++{ ++ return 0; ++} + +\end{lstlisting} + +To add some new functionality it's a good idea to temporarily create a new +branch: + +\begin{lstlisting} +$git branch fancy-new-stuff +$git checkout fancy-new-stuff +Switched to branch 'fance-new-stuff' +\end{lstlisting} + +It's possible to go back in history: + +\begin{lstlisting} +git reset --hard 473cf10e95778c54d49fc6ea368e196f1347ac8a +HEAD is now at 473cf10 initial import of the hello world source +\end{lstlisting} + +Make changes: + +\begin{lstlisting} +#include <stdio.h> + +int main (int argc, char **argv) +{ + printf ("Hello World\n"); + return 0; +} +\end{lstlisting} + +and commit them: + +\begin{lstlisting} +$git commit -sa + +HELLO world + +..not huhu world + +Signed-off-by: Manuel Traut <manut@mecka.net> + +[fance-new-stuff 72e3346] HELLO world + 1 files changed, 3 insertions(+), 0 deletions(-) + +\end{lstlisting} + +You like the new version and want to merge it into your master tree: + +\begin{lstlisting} +$git checkout master +Switched to branch 'master' +$git merge fancy-new-stuff +Auto-merging hello.c +CONFLICT (content): Merge conflict in hello.c +Automatic merge failed; fix conflicts and then commit the result. +\end{lstlisting} + +Git reports an CONFLICT because an automatic merge is not possible. The same +line (printf) has different content in master and fancy-new-stuff. So the merge +conflict has to be resolved by hand. + +hello.c + +\begin{lstlisting} +#include <stdio.h> + +int main (int argc, char **argv) +{ +<<<<<<< HEAD + printf ("Huhu World\n"); +======= + printf ("Hello World\n"); +>>>>>>> fancy-new-stuff + return 0; +} +\end{lstlisting} + +All lines which shouldn't be there can be removed by hand. This result needs +to be commited: + +\begin{lstlisting} +$git commit -sa + +Merge branch 'fance-new-stuff' + +Conflicts: + hello.c + +Signed-off-by: Manuel Traut <manut@mecka.net> +# +# It looks like you may be committing a MERGE. +# If this is not correct, please remove the file +# .git/MERGE_HEAD +# and try again. +# + +# Please enter the commit message for your changes. Lines starting +# with '#' will be ignored, and an empty message aborts the commit. +# On branch master +# Changes to be committed: +# +# modified: hello.c +# + +[master 1815151] Merge branch 'fance-new-stuff' + +$git log + +commit 1815151a08537bd2403605f8adb22852cfdb2d23 +Merge: 6ea27e6 72e3346 +Author: Manuel Traut <manut@mecka.net> +Date: Tue Mar 22 23:57:19 2011 +0100 + + Merge branch 'fance-new-stuff' + + Conflicts: + hello.c + + Signed-off-by: Manuel Traut <manut@mecka.net> + +commit 72e3346872ec9298f2b582e2859b1dbf1304f77e +Author: Manuel Traut <manut@mecka.net> +Date: Tue Mar 22 23:49:58 2011 +0100 + + HELLO world + + ..not huhu world + + Signed-off-by: Manuel Traut <manut@mecka.net> + +... +\end{lstlisting} + +Further exercises: + +\begin{itemize} +\item pull from another repository +\item track a repository +\item what is a bare repository? +\item find bugs with git bisect +\item extract a patch queque from your git branch +\item send mails with git +\item build a svn - git bridge +\end{itemize} + +\input{tailhandout} |