Diffstat (limited to 'Documentation/kernel-parameters.txt')
1 files changed, 76 insertions, 17 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a0c5c5f4fce..033d4e69b43 100644
@@ -315,12 +315,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
CPU-intensive style benchmark, and it can vary highly in
a microbenchmark depending on workload and compiler.
- 1: only for 32-bit processes
- 2: only for 64-bit processes
+ 32: only for 32-bit processes
+ 64: only for 64-bit processes
on: enable for both 32- and 64-bit processes
off: disable for both 32- and 64-bit processes
- amd_iommu= [HW,X86-84]
+ amd_iommu= [HW,X86-64]
Pass parameters to the AMD IOMMU driver in the system.
Possible values are:
fullflush - enable flushing of IO/TLB entries when
@@ -329,6 +329,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
is a lot of faster
off - do not initialize any AMD IOMMU found in
+ force_isolation - Force device isolation for all
+ devices. The IOMMU driver is not
+ allowed anymore to lift isolation
+ requirements as needed. This option
+ does not override iommu=pt
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
@@ -623,6 +628,25 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
[KNL] Disable object debugging
+ [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this
+ parameter allows control of the order of pages that will
+ be intentionally kept free (and hence protected) by the
+ buddy allocator. Bigger value increase the probability
+ of catching random memory corruption, but reduce the
+ amount of memory for normal system use. The maximum
+ possible value is MAX_ORDER/2. Setting this parameter
+ to 1 or 2 should be enough to identify most random
+ memory corruption problems caused by bugs in kernel or
+ driver code when a CPU writes to (or reads from) a
+ random memory location. Note that there exists a class
+ of memory corruptions problems caused by buggy H/W or
+ F/W or by drivers badly programing DMA (basically when
+ memory is written at bus level and the CPU MMU is
+ bypassed) which are not detectable by
+ CONFIG_DEBUG_PAGEALLOC, hence this option will not help
+ tracking down these problems.
debugpat [X86] Enable PAT debugging
@@ -1035,6 +1059,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
By default, super page will be supported if Intel IOMMU
has the capability. With this option, super page will
not be supported.
+ intel_idle.max_cstate= [KNL,HW,ACPI,X86]
+ 0 disables intel_idle and fall back on acpi_idle.
+ 1 to 6 specify maximum depth of C-state.
intremap= [X86-64, Intel-IOMMU]
on enable Interrupt Remapping (default)
off disable Interrupt Remapping
@@ -1059,7 +1088,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
- pt [x86, IA-64]
+ pt [x86, IA-64]
+ group_mf [x86, IA-64]
io7= [HW] IO7 for Marvel based alpha systems
See comment before marvel_specify_io7 in
@@ -1178,9 +1209,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
Default is 0 (don't ignore, but inject #GP)
- kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging.
- Default is 1 (enabled)
kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit
KVM MMU at runtime.
Default is 0 (off)
@@ -1630,12 +1658,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
The default is to return 64-bit inode numbers.
- [NFSv4] When set, this option disables the NFSv4
- idmapper on the client, but only if the mount
- is using the 'sec=sys' security flavour. This may
- make migration from legacy NFSv2/v3 systems easier
- provided that the server has the appropriate support.
- The default is to always enable NFSv4 idmapping.
+ [NFSv4] When set to the default of '1', this option
+ ensures that both the RPC level authentication
+ scheme and the NFS level operations agree to use
+ numeric uids/gids if the mount is using the
+ 'sec=sys' security flavour. In effect it is
+ disabling idmapping, which can make migration from
+ legacy NFSv2/v3 systems to NFSv4 easier.
+ Servers that do not support this mode of operation
+ will be autodetected by the client, and it will fall
+ back to using the idmapper.
+ To turn off this behaviour, set the value to '0'.
nmi_debug= [KNL,AVR32,SH] Specify one or more actions to take
when a NMI is triggered.
@@ -1796,6 +1829,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nomfgpt [X86-32] Disable Multi-Function General Purpose
Timer usage (for AMD Geode machines).
+ nonmi_ipi [X86] Disable using NMI IPIs during panic/reboot to
+ shutdown the other cpus. Instead use the REBOOT_VECTOR
nopat [X86] Disable PAT (page attribute table extension of
@@ -1885,6 +1922,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
arch_perfmon: [X86] Force use of architectural
perfmon on Intel CPUs instead of the
CPU specific event set.
+ timer: [X86] Force use of architectural NMI
+ timer mode (see also oprofile.timer
+ for generic hr timer mode)
+ [s390] Force legacy basic mode sampling
+ (report cpu_type "timer")
oops=panic Always panic on oopses. Default is to just kill the
process, but there is a small probability of
@@ -2362,6 +2404,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
+ slab_max_order= [MM, SLAB]
+ Determines the maximum allowed order for slabs.
+ A high setting may cause OOMs due to memory
+ fragmentation. Defaults to 1 for systems with
+ more than 32MB of RAM, 0 otherwise.
slub_debug[=options[,slabs]] [MM, SLUB]
Enabling slub_debug allows one to determine the
culprit if slab objects become corrupted. Enabling
@@ -2432,6 +2480,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Enabled the stack tracer on boot up.
+ [FTRACE] Limit the functions that the stack tracer
+ will trace at boot up. function-list is a comma separated
+ list of functions. This list can be changed at run
+ time by the stack_trace_filter file in the debugfs
+ tracing directory. Note, this enables stack tracing
+ and the stacktrace above is not needed.
Set the STI (builtin display/keyboard on the HP-PARISC
@@ -2632,6 +2688,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
[USB] Start with the old device initialization
scheme (default 0 = off).
+ [USB] Memory limit (in MB) for buffers allocated by
+ usbfs (default = 16, 0 = max = 2047).
[USB] Try the other device initialization scheme
if the first one fails (default 1 = enabled).
@@ -2750,11 +2810,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
functions are at fixed addresses, they make nice
targets for exploits that can control RIP.
- emulate Vsyscalls turn into traps and are emulated
- reasonably safely.
+ emulate [default] Vsyscalls turn into traps and are
+ emulated reasonably safely.
- native [default] Vsyscalls are native syscall
+ native Vsyscalls are native syscall instructions.
This is a little bit faster than trapping
and makes a few dynamic recompilers work
better than they would in emulation mode.