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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt118
1 files changed, 104 insertions, 14 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 41644336e3..b72e2049c4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -580,6 +580,10 @@
named mounts. Specifying both "all" and "named" disables
all v1 hierarchies.
+ cgroup_favordynmods= [KNL] Enable or Disable favordynmods.
+ Format: { "true" | "false" }
+ Defaults to the value of CONFIG_CGROUP_FAVOR_DYNMODS.
+
cgroup.memory= [KNL] Pass options to the cgroup memory controller.
Format: <string>
nosocket -- Disable socket memory accounting.
@@ -1331,6 +1335,7 @@
earlyprintk=dbgp[debugController#]
earlyprintk=pciserial[,force],bus:device.function[,baudrate]
earlyprintk=xdbc[xhciController#]
+ earlyprintk=bios
earlyprintk is useful when the kernel crashes before
the normal console is initialized. It is not enabled by
@@ -1361,6 +1366,8 @@
The sclp output can only be used on s390.
+ The bios output can only be used on SuperH.
+
The optional "force" to "pciserial" enables use of a
PCI device even when its classcode is not of the
UART class.
@@ -1449,7 +1456,7 @@
See comment before function elanfreq_setup() in
arch/x86/kernel/cpu/cpufreq/elanfreq.c.
- elfcorehdr=[size[KMG]@]offset[KMG] [IA64,PPC,SH,X86,S390]
+ elfcorehdr=[size[KMG]@]offset[KMG] [PPC,SH,X86,S390]
Specifies physical address of start of kernel core
image elf header and optionally the size. Generally
kexec loader will pass this option to capture kernel.
@@ -1512,12 +1519,6 @@
floppy= [HW]
See Documentation/admin-guide/blockdev/floppy.rst.
- force_pal_cache_flush
- [IA-64] Avoid check_sal_cache_flush which may hang on
- buggy SAL_CACHE_FLUSH implementations. Using this
- parameter will force ia64_sal_cache_flush to call
- ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
-
forcepae [X86-32]
Forcefully enable Physical Address Extension (PAE).
Many Pentium M systems disable PAE but may have a
@@ -1893,6 +1894,12 @@
0 -- machine default
1 -- force brightness inversion
+ ia32_emulation= [X86-64]
+ Format: <bool>
+ When true, allows loading 32-bit programs and executing 32-bit
+ syscalls, essentially overriding IA32_EMULATION_DEFAULT_DISABLED at
+ boot time. When false, unconditionally disables IA32 emulation.
+
icn= [HW,ISDN]
Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]]
@@ -2220,7 +2227,7 @@
forcing Dual Address Cycle for PCI cards supporting
greater than 32-bit addressing.
- iommu.strict= [ARM64, X86] Configure TLB invalidation behaviour
+ iommu.strict= [ARM64, X86, S390] Configure TLB invalidation behaviour
Format: { "0" | "1" }
0 - Lazy mode.
Request that DMA unmap operations use deferred
@@ -2913,6 +2920,38 @@
to extract confidential information from the kernel
are also disabled.
+ locktorture.acq_writer_lim= [KNL]
+ Set the time limit in jiffies for a lock
+ acquisition. Acquisitions exceeding this limit
+ will result in a splat once they do complete.
+
+ locktorture.bind_readers= [KNL]
+ Specify the list of CPUs to which the readers are
+ to be bound.
+
+ locktorture.bind_writers= [KNL]
+ Specify the list of CPUs to which the writers are
+ to be bound.
+
+ locktorture.call_rcu_chains= [KNL]
+ Specify the number of self-propagating call_rcu()
+ chains to set up. These are used to ensure that
+ there is a high probability of an RCU grace period
+ in progress at any given time. Defaults to 0,
+ which disables these call_rcu() chains.
+
+ locktorture.long_hold= [KNL]
+ Specify the duration in milliseconds for the
+ occasional long-duration lock hold time. Defaults
+ to 100 milliseconds. Select 0 to disable.
+
+ locktorture.nested_locks= [KNL]
+ Specify the maximum lock nesting depth that
+ locktorture is to exercise, up to a limit of 8
+ (MAX_NESTED_LOCKS). Specify zero to disable.
+ Note that this parameter is ineffective on types
+ of locks that do not support nested acquisition.
+
locktorture.nreaders_stress= [KNL]
Set the number of locking read-acquisition kthreads.
Defaults to being automatically set based on the
@@ -2928,6 +2967,25 @@
Set time (s) between CPU-hotplug operations, or
zero to disable CPU-hotplug testing.
+ locktorture.rt_boost= [KNL]
+ Do periodic testing of real-time lock priority
+ boosting. Select 0 to disable, 1 to boost
+ only rt_mutex, and 2 to boost unconditionally.
+ Defaults to 2, which might seem to be an
+ odd choice, but which should be harmless for
+ non-real-time spinlocks, due to their disabling
+ of preemption. Note that non-realtime mutexes
+ disable boosting.
+
+ locktorture.rt_boost_factor= [KNL]
+ Number that determines how often and for how
+ long priority boosting is exercised. This is
+ scaled down by the number of writers, so that the
+ number of boosts per unit time remains roughly
+ constant as the number of writers increases.
+ On the other hand, the duration of each boost
+ increases with the number of writers.
+
locktorture.shuffle_interval= [KNL]
Set task-shuffle interval (jiffies). Shuffling
tasks allows some CPUs to go into dyntick-idle
@@ -2950,13 +3008,13 @@
locktorture.torture_type= [KNL]
Specify the locking implementation to test.
+ locktorture.verbose= [KNL]
+ Enable additional printk() statements.
+
locktorture.writer_fifo= [KNL]
Run the write-side locktorture kthreads at
sched_set_fifo() real-time priority.
- locktorture.verbose= [KNL]
- Enable additional printk() statements.
-
logibm.irq= [HW,MOUSE] Logitech Bus Mouse Driver
Format: <irq>
@@ -3275,6 +3333,11 @@
mga= [HW,DRM]
+ microcode.force_minrev= [X86]
+ Format: <bool>
+ Enable or disable the microcode minimal revision
+ enforcement for the runtime microcode loader.
+
min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this
physical address is ignored.
@@ -3533,6 +3596,13 @@
[NFS] set the TCP port on which the NFSv4 callback
channel should listen.
+ nfs.delay_retrans=
+ [NFS] specifies the number of times the NFSv4 client
+ retries the request before returning an EAGAIN error,
+ after a reply of NFS4ERR_DELAY from the server.
+ Only applies if the softerr mount option is enabled,
+ and the specified value is >= 0.
+
nfs.enable_ino64=
[NFS] enable 64-bit inode numbers.
If zero, the NFS client will fake up a 32-bit inode
@@ -4769,6 +4839,13 @@
Set maximum number of finished RCU callbacks to
process in one batch.
+ rcutree.do_rcu_barrier= [KNL]
+ Request a call to rcu_barrier(). This is
+ throttled so that userspace tests can safely
+ hammer on the sysfs variable if they so choose.
+ If triggered before the RCU grace-period machinery
+ is fully active, this will error out with EAGAIN.
+
rcutree.dump_tree= [KNL]
Dump the structure of the rcu_node combining tree
out at early boot. This is used for diagnostic
@@ -5225,6 +5302,12 @@
Dump ftrace buffer after reporting RCU CPU
stall warning.
+ rcupdate.rcu_cpu_stall_notifiers= [KNL]
+ Provide RCU CPU stall notifiers, but see the
+ warnings in the RCU_CPU_STALL_NOTIFIER Kconfig
+ option's help text. TL;DR: You almost certainly
+ do not want rcupdate.rcu_cpu_stall_notifiers.
+
rcupdate.rcu_cpu_stall_suppress= [KNL]
Suppress RCU CPU stall warning messages.
@@ -5422,6 +5505,12 @@
test until boot completes in order to avoid
interference.
+ refscale.lookup_instances= [KNL]
+ Number of data elements to use for the forms of
+ SLAB_TYPESAFE_BY_RCU testing. A negative number
+ is negated and multiplied by nr_cpu_ids, while
+ zero specifies nr_cpu_ids.
+
refscale.loops= [KNL]
Set the number of loops over the synchronization
primitive under test. Increasing this number
@@ -5611,9 +5700,10 @@
s390_iommu= [HW,S390]
Set s390 IOTLB flushing mode
strict
- With strict flushing every unmap operation will result in
- an IOTLB flush. Default is lazy flushing before reuse,
- which is faster.
+ With strict flushing every unmap operation will result
+ in an IOTLB flush. Default is lazy flushing before
+ reuse, which is faster. Deprecated, equivalent to
+ iommu.strict=1.
s390_iommu_aperture= [KNL,S390]
Specifies the size of the per device DMA address space