en-US/Kernel.xml
Karsten Wade
quaid at fedoraproject.org
Thu Apr 2 19:42:29 UTC 2009
en-US/Kernel.xml | 174 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 169 insertions(+), 5 deletions(-)
New commits:
commit 659e23727a786d7a359f9372f97d50e2157eda4c
Author: Karsten Wade <kwade at calliope.phig.org>
Date: Thu Apr 2 12:40:49 2009 -0700
Conversion of content from wiki for Preview Release.
* Manual conversion to XML
* Inclusion of section ID content
* Content was edited in the wiki for clarity, etc. prior to conversion
diff --git a/en-US/Kernel.xml b/en-US/Kernel.xml
index 4691ebd..6bf93f3 100644
--- a/en-US/Kernel.xml
+++ b/en-US/Kernel.xml
@@ -2,8 +2,172 @@
<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
]>
-<section>
- <title>Linux Kernel</title>
- <remark>This beat is located here: <ulink type="http" url="https://fedoraproject.org/wiki/Documentation_Kernel_Beat">https://fedoraproject.org/wiki/Documentation_Kernel_Beat</ulink></remark>
- <para>TBD</para>
- </section>
+<section id="sn-Linux_Kernel">
+ <title>Linux Kernel</title>
+ <remark>This beat is located here: <ulink type="http" url="https://fedoraproject.org/wiki/Documentation_Kernel_Beat">https://fedoraproject.org/wiki/Documentation_Kernel_Beat</ulink></remark>
+
+ <para>This section covers changes and important information regarding the 2.6.29 based kernel in Fedora 11.</para>
+
+ <section id="sn-Improved_Performance_and_Reduced_Power_with_relatime">
+ <title>Improved Performance and Reduced Power with relatime</title>
+
+ <para>The <ulink
+ url="http://lwn.net/Articles/244829/">relatime</ulink> option is
+ now enabled by default in Fedora 11. It improves filesystem
+ performance and reduces power consumption.</para>
+
+ <para>The POSIX standard requires operating systems to keep track
+ of the last time each file was accessed by an application or the
+ user, and to store this timestamp as part of the filesystem
+ data. This timestamp, called <firstterm>atime</firstterm>, is used
+ in finding out which files are never used (to clean up the
+ <filename>/tmp</filename> directory for example) or if a file has
+ been looked at after it was last changed.</para>
+
+ <para>A significant downside to atime is that every time a file is
+ accessed, the kernel has to write a new timestamp to the disk, at
+ least after a few seconds of activity. These disk writes keep the
+ disk and the link to the disk busy, which costs both performance
+ and power.</para>
+
+ <para>Because some programs use atime, disabling by default is not
+ practical. The Linux kernel has a feature called
+ <firstterm>relatime</firstterm>, which is an effective compromise
+ between having some of the information that atime provides,
+ without having the disk time updated as regularly. It works by
+ updating the atime field on disk only if the file hasn't been
+ accessed since the last time it was accessed (to provide the new
+ email detection capability) or when the last access was more than
+ 1 day ago (to help programs and users clean up unused files in the
+ <filename>/tmp</filename> directory). An improved version of
+ relatime has been <ulink
+ url="https://www.redhat.com/archives/fedora-devel-list/2009-March/msg01612.html">merged
+ upstream</ulink> by Fedora developers in the 2.6.30 kernel and
+ backported to the Fedora 11 kernel.</para>
+ </section>
+ <section id="sn-Version">
+ <title>Version</title>
+
+ <para>Fedora may include additional patches to the kernel for
+ improvements, bug fixes, or additional features. For this reason,
+ the Fedora kernel may not be line-for-line equivalent to the
+ so-called <firstterm>vanilla kernel</firstterm> from the
+ kernel.org web site:</para>
+
+ <para><ulink url="http://www.kernel.org/"/></para>
+
+ <para>To obtain a list of these patches, download the source RPM
+ package and run the following command against it:</para>
+
+ <screen>
+ <command>rpm -qpl kernel-<version>.src.rpm</command>
+ </screen>
+ </section>
+ <section id="sn-Changelog">
+ <title>Changelog</title>
+
+ <para>To retrieve a log of changes to the package, run the
+ following command:</para>
+
+ <screen>
+ <command>rpm -q --changelog kernel-<version></command>
+ </screen>
+
+ <para>If you need a user friendly version of the changelog, refer
+ to <ulink url="http://wiki.kernelnewbies.org/LinuxChanges"/>. A
+ short and full diff of the kernel is available from <ulink
+ url="http://kernel.org/git"/>. The Fedora version kernel is based
+ on the Linus tree.</para>
+
+ <para>Customizations made for the Fedora version are available
+ from <ulink url="http://cvs.fedoraproject.org"/>.</para>
+ </section>
+ <section id="sn-Kernel_Flavors">
+ <title>Kernel Flavors</title>
+
+ <para>Fedora 11 includes the following kernel builds:</para>
+ <itemizedlist>
+ <listitem>
+ <para>Native kernel, for use in most systems. Configured
+ sources are available in the <package>kernel-devel</package>
+ package.</para>
+ </listitem>
+ <listitem>
+ <para>The kernel-PAE, for use in 32-bit x86 systems with more
+ than 4GB of RAM, or with CPUs that have a NX (No eXecute)
+ feature. This kernel supports both uniprocessor and
+ multi-processor systems. Configured sources are available in
+ the <package>kernel-PAE-devel</package> package.</para>
+ </listitem>
+ <listitem>
+ <para>Debugging kernel, for use in debugging some kernel
+ issues. Configured sources are available in the
+ <package>kernel-debug-devel</package> package.</para>
+ </listitem>
+ </itemizedlist>
+
+ <para>You may install kernel headers for all four kernel flavors
+ at the same time. The files are installed in the
+ <filename>/usr/src/kernels/<version>[-PAE|-xen|-kdump]
+ -<arch>/</filename> tree. Use the following command:
+ </para>
+ <screen>
+ <command>su -c 'yum install kernel{,-PAE,-xen,-kdump}-devel'</command>
+ </screen>
+
+ <para>Select one or more of these flavors, separated by commas and
+ no spaces, as appropriate. Enter the root password when
+ prompted.</para>
+
+ <note>
+ <title>x86 Kernel Includes Kdump</title>
+ <para>Both the x86_64 and the i686 kernels are relocatable, so
+ they no longer require a separate kernel for kdump
+ capability. PPC64 still requires a separate kdump kernel.</para>
+ </note>
+ <note>
+ <title>x86 Kernel Includes Paravirtualization</title>
+ <para>Both the x86_64 and the i686 kernels contain paravirt_ops
+ support, so they no longer require a separate kernel for running
+ under a Xen hypervisor.</para>
+ </note>
+ <note>
+ <title>Default Kernel Provides SMP</title>
+ <para>There is no separate SMP kernel available for Fedora on
+ i386, x86_64, and ppc64. Multiprocessor support is provided by
+ the native kernel.</para>
+ </note>
+ <note>
+ <title>PowerPC Kernel Support</title>
+ <para>There is no support for Xen or kdump for the PowerPC
+ architecture in Fedora. 32-bit PowerPC still has a separate SMP
+ kernel.</para>
+ </note>
+ </section>
+ <section id="sn-Preparing_for_Kernel_Development">
+ <title>Preparing for Kernel Development</title>
+
+ <para>Fedora 11 does not include the
+ <package>kernel-source</package> package provided by older
+ versions since only the <package>kernel-devel</package> package is
+ required now to build external modules. Configured sources are
+ available, as described in <xref
+ linkend="sn-Kernel_Flavors"/>.</para>
+
+ <important>
+ <title>Custom Kernel Building</title>
+ <para>For information on kernel development and working with
+ custom kernels, refer to <ulink
+ url="http://fedoraproject.org/wiki/Building_a_custom_kernel"/>.</para>
+ </important>
+ </section>
+ <section id="sn-Reporting_Bugs">
+ <title>Reporting Bugs</title>
+
+ <para>Refer to <ulink
+ url="http://kernel.org/pub/linux/docs/lkml/reporting-bugs.html"/>
+ for information on reporting bugs in the Linux kernel. You may
+ also use <ulink url="http://bugzilla.redhat.com"/> for reporting
+ bugs that are specific to Fedora.</para>
+ </section>
+</section>
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