Documentation: refresh sysctl/kernel.txt
Refresh sysctl/kernel.txt. More specifically, - drop stale index entries - sync and sort index and entries - reflow sticking out paragraphs to colwidth 72 - correct typos - cleanup whitespace Signed-off-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
9fd615f466
commit
807094c0b1
|
@ -17,23 +17,21 @@ before actually making adjustments.
|
||||||
|
|
||||||
Currently, these files might (depending on your configuration)
|
Currently, these files might (depending on your configuration)
|
||||||
show up in /proc/sys/kernel:
|
show up in /proc/sys/kernel:
|
||||||
- acpi_video_flags
|
|
||||||
- acct
|
- acct
|
||||||
|
- acpi_video_flags
|
||||||
|
- auto_msgmni
|
||||||
- bootloader_type [ X86 only ]
|
- bootloader_type [ X86 only ]
|
||||||
- bootloader_version [ X86 only ]
|
- bootloader_version [ X86 only ]
|
||||||
- callhome [ S390 only ]
|
- callhome [ S390 only ]
|
||||||
- auto_msgmni
|
|
||||||
- core_pattern
|
- core_pattern
|
||||||
- core_pipe_limit
|
- core_pipe_limit
|
||||||
- core_uses_pid
|
- core_uses_pid
|
||||||
- ctrl-alt-del
|
- ctrl-alt-del
|
||||||
- dentry-state
|
|
||||||
- dmesg_restrict
|
- dmesg_restrict
|
||||||
- domainname
|
- domainname
|
||||||
- hostname
|
- hostname
|
||||||
- hotplug
|
- hotplug
|
||||||
- java-appletviewer [ binfmt_java, obsolete ]
|
|
||||||
- java-interpreter [ binfmt_java, obsolete ]
|
|
||||||
- kptr_restrict
|
- kptr_restrict
|
||||||
- kstack_depth_to_print [ X86 only ]
|
- kstack_depth_to_print [ X86 only ]
|
||||||
- l2cr [ PPC only ]
|
- l2cr [ PPC only ]
|
||||||
|
@ -48,10 +46,14 @@ show up in /proc/sys/kernel:
|
||||||
- overflowgid
|
- overflowgid
|
||||||
- overflowuid
|
- overflowuid
|
||||||
- panic
|
- panic
|
||||||
|
- panic_on_oops
|
||||||
|
- panic_on_unrecovered_nmi
|
||||||
- pid_max
|
- pid_max
|
||||||
- powersave-nap [ PPC only ]
|
- powersave-nap [ PPC only ]
|
||||||
- panic_on_unrecovered_nmi
|
|
||||||
- printk
|
- printk
|
||||||
|
- printk_delay
|
||||||
|
- printk_ratelimit
|
||||||
|
- printk_ratelimit_burst
|
||||||
- randomize_va_space
|
- randomize_va_space
|
||||||
- real-root-dev ==> Documentation/initrd.txt
|
- real-root-dev ==> Documentation/initrd.txt
|
||||||
- reboot-cmd [ SPARC only ]
|
- reboot-cmd [ SPARC only ]
|
||||||
|
@ -62,6 +64,7 @@ show up in /proc/sys/kernel:
|
||||||
- shmall
|
- shmall
|
||||||
- shmmax [ sysv ipc ]
|
- shmmax [ sysv ipc ]
|
||||||
- shmmni
|
- shmmni
|
||||||
|
- softlockup_thresh
|
||||||
- stop-a [ SPARC only ]
|
- stop-a [ SPARC only ]
|
||||||
- sysrq ==> Documentation/sysrq.txt
|
- sysrq ==> Documentation/sysrq.txt
|
||||||
- tainted
|
- tainted
|
||||||
|
@ -71,15 +74,6 @@ show up in /proc/sys/kernel:
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
acpi_video_flags:
|
|
||||||
|
|
||||||
flags
|
|
||||||
|
|
||||||
See Doc*/kernel/power/video.txt, it allows mode of video boot to be
|
|
||||||
set during run time.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
acct:
|
acct:
|
||||||
|
|
||||||
highwater lowwater frequency
|
highwater lowwater frequency
|
||||||
|
@ -95,6 +89,25 @@ That is, suspend accounting if there left <= 2% free; resume it
|
||||||
if we got >=4%; consider information about amount of free space
|
if we got >=4%; consider information about amount of free space
|
||||||
valid for 30 seconds.
|
valid for 30 seconds.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
|
acpi_video_flags:
|
||||||
|
|
||||||
|
flags
|
||||||
|
|
||||||
|
See Doc*/kernel/power/video.txt, it allows mode of video boot to be
|
||||||
|
set during run time.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
|
auto_msgmni:
|
||||||
|
|
||||||
|
Enables/Disables automatic recomputing of msgmni upon memory add/remove
|
||||||
|
or upon ipc namespace creation/removal (see the msgmni description
|
||||||
|
above). Echoing "1" into this file enables msgmni automatic recomputing.
|
||||||
|
Echoing "0" turns it off. auto_msgmni default value is 1.
|
||||||
|
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
bootloader_type:
|
bootloader_type:
|
||||||
|
@ -172,22 +185,24 @@ core_pattern is used to specify a core dumpfile pattern name.
|
||||||
|
|
||||||
core_pipe_limit:
|
core_pipe_limit:
|
||||||
|
|
||||||
This sysctl is only applicable when core_pattern is configured to pipe core
|
This sysctl is only applicable when core_pattern is configured to pipe
|
||||||
files to a user space helper (when the first character of core_pattern is a '|',
|
core files to a user space helper (when the first character of
|
||||||
see above). When collecting cores via a pipe to an application, it is
|
core_pattern is a '|', see above). When collecting cores via a pipe
|
||||||
occasionally useful for the collecting application to gather data about the
|
to an application, it is occasionally useful for the collecting
|
||||||
crashing process from its /proc/pid directory. In order to do this safely, the
|
application to gather data about the crashing process from its
|
||||||
kernel must wait for the collecting process to exit, so as not to remove the
|
/proc/pid directory. In order to do this safely, the kernel must wait
|
||||||
crashing processes proc files prematurely. This in turn creates the possibility
|
for the collecting process to exit, so as not to remove the crashing
|
||||||
that a misbehaving userspace collecting process can block the reaping of a
|
processes proc files prematurely. This in turn creates the
|
||||||
crashed process simply by never exiting. This sysctl defends against that. It
|
possibility that a misbehaving userspace collecting process can block
|
||||||
defines how many concurrent crashing processes may be piped to user space
|
the reaping of a crashed process simply by never exiting. This sysctl
|
||||||
applications in parallel. If this value is exceeded, then those crashing
|
defends against that. It defines how many concurrent crashing
|
||||||
processes above that value are noted via the kernel log and their cores are
|
processes may be piped to user space applications in parallel. If
|
||||||
skipped. 0 is a special value, indicating that unlimited processes may be
|
this value is exceeded, then those crashing processes above that value
|
||||||
captured in parallel, but that no waiting will take place (i.e. the collecting
|
are noted via the kernel log and their cores are skipped. 0 is a
|
||||||
process is not guaranteed access to /proc/<crashing pid>/). This value defaults
|
special value, indicating that unlimited processes may be captured in
|
||||||
to 0.
|
parallel, but that no waiting will take place (i.e. the collecting
|
||||||
|
process is not guaranteed access to /proc/<crashing pid>/). This
|
||||||
|
value defaults to 0.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
@ -218,14 +233,14 @@ to decide what to do with it.
|
||||||
|
|
||||||
dmesg_restrict:
|
dmesg_restrict:
|
||||||
|
|
||||||
This toggle indicates whether unprivileged users are prevented from using
|
This toggle indicates whether unprivileged users are prevented
|
||||||
dmesg(8) to view messages from the kernel's log buffer. When
|
from using dmesg(8) to view messages from the kernel's log buffer.
|
||||||
dmesg_restrict is set to (0) there are no restrictions. When
|
When dmesg_restrict is set to (0) there are no restrictions. When
|
||||||
dmesg_restrict is set set to (1), users must have CAP_SYSLOG to use
|
dmesg_restrict is set set to (1), users must have CAP_SYSLOG to use
|
||||||
dmesg(8).
|
dmesg(8).
|
||||||
|
|
||||||
The kernel config option CONFIG_SECURITY_DMESG_RESTRICT sets the default
|
The kernel config option CONFIG_SECURITY_DMESG_RESTRICT sets the
|
||||||
value of dmesg_restrict.
|
default value of dmesg_restrict.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
@ -256,13 +271,6 @@ Default value is "/sbin/hotplug".
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
l2cr: (PPC only)
|
|
||||||
|
|
||||||
This flag controls the L2 cache of G3 processor boards. If
|
|
||||||
0, the cache is disabled. Enabled if nonzero.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
kptr_restrict:
|
kptr_restrict:
|
||||||
|
|
||||||
This toggle indicates whether restrictions are placed on
|
This toggle indicates whether restrictions are placed on
|
||||||
|
@ -283,6 +291,13 @@ kernel stack.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
l2cr: (PPC only)
|
||||||
|
|
||||||
|
This flag controls the L2 cache of G3 processor boards. If
|
||||||
|
0, the cache is disabled. Enabled if nonzero.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
modules_disabled:
|
modules_disabled:
|
||||||
|
|
||||||
A toggle value indicating if modules are allowed to be loaded
|
A toggle value indicating if modules are allowed to be loaded
|
||||||
|
@ -293,6 +308,21 @@ to false.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
nmi_watchdog:
|
||||||
|
|
||||||
|
Enables/Disables the NMI watchdog on x86 systems. When the value is
|
||||||
|
non-zero the NMI watchdog is enabled and will continuously test all
|
||||||
|
online cpus to determine whether or not they are still functioning
|
||||||
|
properly. Currently, passing "nmi_watchdog=" parameter at boot time is
|
||||||
|
required for this function to work.
|
||||||
|
|
||||||
|
If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel
|
||||||
|
parameter), the NMI watchdog shares registers with oprofile. By
|
||||||
|
disabling the NMI watchdog, oprofile may have more registers to
|
||||||
|
utilize.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
osrelease, ostype & version:
|
osrelease, ostype & version:
|
||||||
|
|
||||||
# cat osrelease
|
# cat osrelease
|
||||||
|
@ -312,10 +342,10 @@ The only way to tune these values is to rebuild the kernel :-)
|
||||||
|
|
||||||
overflowgid & overflowuid:
|
overflowgid & overflowuid:
|
||||||
|
|
||||||
if your architecture did not always support 32-bit UIDs (i.e. arm, i386,
|
if your architecture did not always support 32-bit UIDs (i.e. arm,
|
||||||
m68k, sh, and sparc32), a fixed UID and GID will be returned to
|
i386, m68k, sh, and sparc32), a fixed UID and GID will be returned to
|
||||||
applications that use the old 16-bit UID/GID system calls, if the actual
|
applications that use the old 16-bit UID/GID system calls, if the
|
||||||
UID or GID would exceed 65535.
|
actual UID or GID would exceed 65535.
|
||||||
|
|
||||||
These sysctls allow you to change the value of the fixed UID and GID.
|
These sysctls allow you to change the value of the fixed UID and GID.
|
||||||
The default is 65534.
|
The default is 65534.
|
||||||
|
@ -324,9 +354,22 @@ The default is 65534.
|
||||||
|
|
||||||
panic:
|
panic:
|
||||||
|
|
||||||
The value in this file represents the number of seconds the
|
The value in this file represents the number of seconds the kernel
|
||||||
kernel waits before rebooting on a panic. When you use the
|
waits before rebooting on a panic. When you use the software watchdog,
|
||||||
software watchdog, the recommended setting is 60.
|
the recommended setting is 60.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
|
panic_on_unrecovered_nmi:
|
||||||
|
|
||||||
|
The default Linux behaviour on an NMI of either memory or unknown is
|
||||||
|
to continue operation. For many environments such as scientific
|
||||||
|
computing it is preferable that the box is taken out and the error
|
||||||
|
dealt with than an uncorrected parity/ECC error get propagated.
|
||||||
|
|
||||||
|
A small number of systems do generate NMI's for bizarre random reasons
|
||||||
|
such as power management so the default is off. That sysctl works like
|
||||||
|
the existing panic controls already in that directory.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
@ -376,6 +419,14 @@ the different loglevels.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
|
printk_delay:
|
||||||
|
|
||||||
|
Delay each printk message in printk_delay milliseconds
|
||||||
|
|
||||||
|
Value from 0 - 10000 is allowed.
|
||||||
|
|
||||||
|
==============================================================
|
||||||
|
|
||||||
printk_ratelimit:
|
printk_ratelimit:
|
||||||
|
|
||||||
Some warning messages are rate limited. printk_ratelimit specifies
|
Some warning messages are rate limited. printk_ratelimit specifies
|
||||||
|
@ -395,15 +446,7 @@ send before ratelimiting kicks in.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
printk_delay:
|
randomize_va_space:
|
||||||
|
|
||||||
Delay each printk message in printk_delay milliseconds
|
|
||||||
|
|
||||||
Value from 0 - 10000 is allowed.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
randomize-va-space:
|
|
||||||
|
|
||||||
This option can be used to select the type of process address
|
This option can be used to select the type of process address
|
||||||
space randomization that is used in the system, for architectures
|
space randomization that is used in the system, for architectures
|
||||||
|
@ -466,11 +509,11 @@ are doing anyway :)
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
shmmax:
|
shmmax:
|
||||||
|
|
||||||
This value can be used to query and set the run time limit
|
This value can be used to query and set the run time limit
|
||||||
on the maximum shared memory segment size that can be created.
|
on the maximum shared memory segment size that can be created.
|
||||||
Shared memory segments up to 1Gb are now supported in the
|
Shared memory segments up to 1Gb are now supported in the
|
||||||
kernel. This value defaults to SHMMAX.
|
kernel. This value defaults to SHMMAX.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
@ -484,7 +527,7 @@ tunable to zero will disable the softlockup detection altogether.
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
tainted:
|
tainted:
|
||||||
|
|
||||||
Non-zero if the kernel has been tainted. Numeric values, which
|
Non-zero if the kernel has been tainted. Numeric values, which
|
||||||
can be ORed together:
|
can be ORed together:
|
||||||
|
@ -509,49 +552,11 @@ can be ORed together:
|
||||||
|
|
||||||
==============================================================
|
==============================================================
|
||||||
|
|
||||||
auto_msgmni:
|
|
||||||
|
|
||||||
Enables/Disables automatic recomputing of msgmni upon memory add/remove or
|
|
||||||
upon ipc namespace creation/removal (see the msgmni description above).
|
|
||||||
Echoing "1" into this file enables msgmni automatic recomputing.
|
|
||||||
Echoing "0" turns it off.
|
|
||||||
auto_msgmni default value is 1.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
nmi_watchdog:
|
|
||||||
|
|
||||||
Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero
|
|
||||||
the NMI watchdog is enabled and will continuously test all online cpus to
|
|
||||||
determine whether or not they are still functioning properly. Currently,
|
|
||||||
passing "nmi_watchdog=" parameter at boot time is required for this function
|
|
||||||
to work.
|
|
||||||
|
|
||||||
If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the
|
|
||||||
NMI watchdog shares registers with oprofile. By disabling the NMI watchdog,
|
|
||||||
oprofile may have more registers to utilize.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
unknown_nmi_panic:
|
unknown_nmi_panic:
|
||||||
|
|
||||||
The value in this file affects behavior of handling NMI. When the value is
|
The value in this file affects behavior of handling NMI. When the
|
||||||
non-zero, unknown NMI is trapped and then panic occurs. At that time, kernel
|
value is non-zero, unknown NMI is trapped and then panic occurs. At
|
||||||
debugging information is displayed on console.
|
that time, kernel debugging information is displayed on console.
|
||||||
|
|
||||||
NMI switch that most IA32 servers have fires unknown NMI up, for example.
|
|
||||||
If a system hangs up, try pressing the NMI switch.
|
|
||||||
|
|
||||||
==============================================================
|
|
||||||
|
|
||||||
panic_on_unrecovered_nmi:
|
|
||||||
|
|
||||||
The default Linux behaviour on an NMI of either memory or unknown is to continue
|
|
||||||
operation. For many environments such as scientific computing it is preferable
|
|
||||||
that the box is taken out and the error dealt with than an uncorrected
|
|
||||||
parity/ECC error get propogated.
|
|
||||||
|
|
||||||
A small number of systems do generate NMI's for bizarre random reasons such as
|
|
||||||
power management so the default is off. That sysctl works like the existing
|
|
||||||
panic controls already in that directory.
|
|
||||||
|
|
||||||
|
NMI switch that most IA32 servers have fires unknown NMI up, for
|
||||||
|
example. If a system hangs up, try pressing the NMI switch.
|
||||||
|
|
Loading…
Reference in New Issue