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Documentation for /proc/sys/kernel/
===================================
.. See scripts/check-sysctl-docs to keep this up to date
Copyright (c) 1998, 1999, Rik van Riel <riel@nl.linux.org>
Copyright (c) 2009, Shen Feng<shen@cn.fujitsu.com>
For general info and legal blurb, please look in :doc:`index`.
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This file contains documentation for the sysctl files in
``/proc/sys/kernel/`` and is valid for Linux kernel version 2.2.
The files in this directory can be used to tune and monitor
miscellaneous and general things in the operation of the Linux
kernel. Since some of the files *can* be used to screw up your
system, it is advisable to read both documentation and source
before actually making adjustments.
Currently, these files might (depending on your configuration)
show up in ``/proc/sys/kernel``:
.. contents:: :local:
acct
====
::
highwater lowwater frequency
If BSD-style process accounting is enabled these values control
its behaviour. If free space on filesystem where the log lives
goes below ``lowwater``% accounting suspends. If free space gets
above ``highwater``% accounting resumes. ``frequency`` determines
how often do we check the amount of free space (value is in
seconds). Default:
::
4 2 30
That is, suspend accounting if free space drops below 2%; resume it
if it increases to at least 4%; consider information about amount of
free space valid for 30 seconds.
acpi_video_flags
================
See :doc:`/power/video`. This allows the video resume mode to be set,
in a similar fashion to the ``acpi_sleep`` kernel parameter, by
combining the following values:
= =======
1 s3_bios
2 s3_mode
4 s3_beep
= =======
auto_msgmni
===========
This variable has no effect and may be removed in future kernel
releases. Reading it always returns 0.
Up to Linux 3.17, it enabled/disabled automatic recomputing of
`msgmni`_
upon memory add/remove or upon IPC namespace creation/removal.
Echoing "1" into this file enabled msgmni automatic recomputing.
Echoing "0" turned it off. The default value was 1.
bootloader_type (x86 only)
==========================
This gives the bootloader type number as indicated by the bootloader,
shifted left by 4, and OR'd with the low four bits of the bootloader
version. The reason for this encoding is that this used to match the
