Date: Thu, 6 Dec 2012 20:22:42 GMT From: Bas Smeelen <b.smeelen@ose.nl> To: freebsd-gnats-submit@FreeBSD.org Subject: docs/174244: [patch] faq: why-kernel-big Message-ID: <201212062022.qB6KMg6a034410@red.freebsd.org> Resent-Message-ID: <201212062030.qB6KU1Zr061551@freefall.freebsd.org>
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>Number: 174244
>Category: docs
>Synopsis: [patch] faq: why-kernel-big
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-doc
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: update
>Submitter-Id: current-users
>Arrival-Date: Thu Dec 06 20:30:00 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator: Bas Smeelen
>Release: 9.1
>Organization:
>Environment:
>Description:
update faq and add more information
>How-To-Repeat:
>Fix:
Index: en_US.ISO8859-1/books/faq/book.xml
===================================================================
--- en_US.ISO8859-1/books/faq/book.xml (revision 40284)
+++ en_US.ISO8859-1/books/faq/book.xml (working copy)
@@ -4114,18 +4114,27 @@
</question>
<answer>
- <para>Chances are, you compiled your kernel in <emphasis>debug
- mode</emphasis>. Kernels built in debug mode contain many
- symbols that are used for debugging, thus greatly increasing
- the size of the kernel. Note that there will be little or
- no performance decrease from running a debug kernel, and it
- is useful to keep one around in case of a system
- panic.</para>
+ <para>GENERIC kernels shipped with &os; 7.x and later are compiled
+ in <emphasis>debug mode</emphasis>. Kernels built in debug mode
+ contain many symbols in separate files that are used for
+ debugging, thus greatly increasing the size of /boot/kernel/.
+ Note that there will be little or no performance decrease
+ from running a debug kernel, and it is useful to keep one around
+ in case of a system panic.</para>
- <para>However, if you are running low on disk space, or you
- simply do not want to run a debug kernel, make sure that
- both of the following are true:</para>
+ <para>However, if you are running low on disk space, there are
+ different options to reduce the size of /boot/kernel/.</para>
+ <para>- If you do not want the symbol files to be installed,
+ make sure you have the following line present in /etc/src.conf:
+
+ <programlisting>WITHOUT_KERNEL_SYMBOLS=yes</programlisting>
+
+ For more information see &man.src.conf.5</para>
+
+ <para>- If you simply do not want to build a debug kernel, make
+ sure that both of the following are true:</para>
+
<itemizedlist>
<listitem>
<para>You do not have a line in your kernel configuration
@@ -4142,9 +4151,30 @@
<para>Either of the above settings will cause your kernel to
be built in debug mode. As long as you make sure you follow
- the steps above, you can build your kernel normally, and you
- should notice a fairly large size decrease; most kernels
- tend to be around 1.5 MB to 2 MB.</para>
+ the steps above, you can build your kernel normally</para>
+
+ <para>- If you want only the modules you use to be built
+ and installed, make sure you have a line like below in
+ /etc/make.conf:</para>
+
+ <programlisting>MODULES_OVERRIDE= accf_http ipfw</programlisting>
+
+ <para>Replace <emphasis>accf_httpd ipfw</emphasis> with a list
+ of modules you need. Only these modules will be built. This
+ does not only reduce the size of the kernel directory but
+ also decreases the amount of time needed to build your kernel.
+ For more information see /usr/share/examples/etc/make.conf
+ </para>
+
+ <para>- You can also remove unneeded devices from your kernel
+ to further reduce the size. See <xref linkend="make-kernel"
+ remap="another section"/>for more information.</para>
+
+ <para>To put any of these options into effect you will have
+ to build and install your new kernel.</para>
+
+ <para>Most kernels (/boot/kernel/kernel)
+ tend to be around 12 MB to 16 MB.</para>
</answer>
</qandaentry>
>Release-Note:
>Audit-Trail:
>Unformatted:
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