Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-12-29 17:25:38 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Documentation: admin: reorganize kernel-parameters intro

Browse Source 
Reorganize the introduction to the kernel-parameters file to place
related paragraphs together:

- move module info together and near the beginning
- add a Special Handling section for dashes, underscores, double quotes,
  cpu lists, and metric (KMG) suffixes. Expand the KMG suffixes to
  include TPE as well.
- add a Kernel Build Options section

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241029180320.412629-1-rdunlap@infradead.org
This commit is contained in:
Randy Dunlap 2024-10-29 11:03:20 -07:00 committed by Jonathan Corbet
parent 062d98be0e
commit 32643e10df
1 changed files with 23 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
Documentation/admin-guide/kernel-parameters.rst
View File

@ -27,6 +27,16 @@ kernel command line (/proc/cmdline) and collects module parameters
when it loads a module, so the kernel command line can be used for
loadable modules too.
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
module. Loadable modules, after being loaded into the running kernel, also
reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
parameters may be changed at runtime by the command
``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``.
Special handling
----------------
Hyphens (dashes) and underscores are equivalent in parameter names, so::
log_buf_len=1M print-fatal-signals=1
@ -39,8 +49,8 @@ Double-quotes can be used to protect spaces in values, e.g.::
param="spaces in here"
cpu lists:
----------
cpu lists
~~~~~~~~~
Some kernel parameters take a list of CPUs as a value, e.g. isolcpus,
nohz_full, irqaffinity, rcu_nocbs. The format of this list is:
@ -82,12 +92,17 @@ so that "nohz_full=all" is the equivalent of "nohz_full=0-N".
The semantics of "N" and "all" is supported on a level of bitmaps and holds for
all users of bitmap_parselist().
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
module. Loadable modules, after being loaded into the running kernel, also
reveal their parameters in /sys/module/${modulename}/parameters/. Some of these
parameters may be changed at runtime by the command
``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``.
Metric suffixes
~~~~~~~~~~~~~~~
The [KMG] suffix is commonly described after a number of kernel
parameter values. 'K', 'M', 'G', 'T', 'P', and 'E' suffixes are allowed.
These letters represent the _binary_ multipliers 'Kilo', 'Mega', 'Giga',
'Tera', 'Peta', and 'Exa', equaling 2^10, 2^20, 2^30, 2^40, 2^50, and
2^60 bytes respectively. Such letter suffixes can also be entirely omitted.
Kernel Build Options
--------------------
The parameters listed below are only valid if certain kernel build options
were enabled and if respective hardware is present. This list should be kept
@ -211,10 +226,5 @@ a fixed number of characters. This limit depends on the architecture
and is between 256 and 4096 characters. It is defined in the file
./include/uapi/asm-generic/setup.h as COMMAND_LINE_SIZE.
Finally, the [KMG] suffix is commonly described after a number of kernel
parameter values. These 'K', 'M', and 'G' letters represent the _binary_
multipliers 'Kilo', 'Mega', and 'Giga', equaling 2^10, 2^20, and 2^30
bytes respectively. Such letter suffixes can also be entirely omitted:
.. include:: kernel-parameters.txt
:literal: