allowed anymore to lift isolation
requirements as needed. This option
does not override iommu=pt
- force_enable - Force enable the IOMMU on platforms known
- to be buggy with IOMMU enabled. Use this
- option with care.
- pgtbl_v1 - Use v1 page table for DMA-API (Default).
- pgtbl_v2 - Use v2 page table for DMA-API.
- irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
+ force_enable - Force enable the IOMMU on platforms known
+ to be buggy with IOMMU enabled. Use this
+ option with care.
+ pgtbl_v1 - Use v1 page table for DMA-API (Default).
+ pgtbl_v2 - Use v2 page table for DMA-API.
+ irtcachedis - Disable Interrupt Remapping Table (IRT) caching.
+ nohugepages - Limit page-sizes used for v1 page-tables
+ to 4 KiB.
+ v2_pgsizes_only - Limit page-sizes used for v1 page-tables
+ to 4KiB/2Mib/1GiB.
+
amd_iommu_dump= [HW,X86-64]
Enable AMD IOMMU driver option to dump the ACPI table
Format: <io>,<irq>,<mode>
See header of drivers/net/hamradio/baycom_ser_hdx.c.
+ bdev_allow_write_mounted=
+ Format: <bool>
+ Control the ability to open a mounted block device
+ for writing, i.e., allow / disallow writes that bypass
+ the FS. This was implemented as a means to prevent
+ fuzzers from crashing the kernel by overwriting the
+ metadata underneath a mounted FS without its awareness.
+ This also prevents destructive formatting of mounted
+ filesystems by naive storage tooling that don't use
+ O_EXCL. Default is Y and can be changed through the
+ Kconfig option CONFIG_BLK_DEV_WRITE_MOUNTED.
+
bert_disable [ACPI]
Disable BERT OS support on buggy BIOSes.
ipcmni_extend [KNL,EARLY] Extend the maximum number of unique System V
IPC identifiers from 32,768 to 16,777,216.
+ ipe.enforce= [IPE]
+ Format: <bool>
+ Determine whether IPE starts in permissive (0) or
+ enforce (1) mode. The default is enforce.
+
+ ipe.success_audit=
+ [IPE]
+ Format: <bool>
+ Start IPE with success auditing enabled, emitting
+ an audit event when a binary is allowed. The default
+ is 0.
+
irqaffinity= [SMP] Set the default irq affinity mask
The argument is a cpu list, as described above.
Disable NUMA, Only set up a single NUMA node
spanning all memory.
+ numa=fake=<size>[MG]
+ [KNL, ARM64, RISCV, X86, EARLY]
+ If given as a memory unit, fills all system RAM with
+ nodes of size interleaved over physical nodes.
+
+ numa=fake=<N>
+ [KNL, ARM64, RISCV, X86, EARLY]
+ If given as an integer, fills all system RAM with N
+ fake nodes interleaved over physical nodes.
+
+ numa=fake=<N>U
+ [KNL, ARM64, RISCV, X86, EARLY]
+ If given as an integer followed by 'U', it will
+ divide each physical node into N emulated nodes.
+
numa_balancing= [KNL,ARM64,PPC,RISCV,S390,X86] Enable or disable automatic
NUMA balancing.
Allowed values are enable and disable
printk.time= Show timing data prefixed to each printk message line
Format: <bool> (1/Y/y=enable, 0/N/n=disable)
+ proc_mem.force_override= [KNL]
+ Format: {always | ptrace | never}
+ Traditionally /proc/pid/mem allows memory permissions to be
+ overridden without restrictions. This option may be set to
+ restrict that. Can be one of:
+ - 'always': traditional behavior always allows mem overrides.
+ - 'ptrace': only allow mem overrides for active ptracers.
+ - 'never': never allow mem overrides.
+ If not specified, default is the CONFIG_PROC_MEM_* choice.
+
processor.max_cstate= [HW,ACPI]
Limit processor to maximum C-state
max_cstate=9 overrides any DMI blacklist limit.
Set maximum number of finished RCU callbacks to
process in one batch.
+ rcutree.csd_lock_suppress_rcu_stall= [KNL]
+ Do only a one-line RCU CPU stall warning when
+ there is an ongoing too-long CSD-lock wait.
+
rcutree.do_rcu_barrier= [KNL]
Request a call to rcu_barrier(). This is
throttled so that userspace tests can safely
Time to wait (s) after boot before inducing stall.
rcutorture.stall_cpu_irqsoff= [KNL]
- Disable interrupts while stalling if set.
+ Disable interrupts while stalling if set, but only
+ on the first stall in the set.
+
+ rcutorture.stall_cpu_repeat= [KNL]
+ Number of times to repeat the stall sequence,
+ so that rcutorture.stall_cpu_repeat=3 will result
+ in four stall sequences.
rcutorture.stall_gp_kthread= [KNL]
Duration (s) of forced sleep within RCU
of zero will disable batching. Batching is
always disabled for synchronize_rcu_tasks().
- rcupdate.rcu_tasks_rude_lazy_ms= [KNL]
- Set timeout in milliseconds RCU Tasks
- Rude asynchronous callback batching for
- call_rcu_tasks_rude(). A negative value
- will take the default. A value of zero will
- disable batching. Batching is always disabled
- for synchronize_rcu_tasks_rude().
-
rcupdate.rcu_tasks_trace_lazy_ms= [KNL]
Set timeout in milliseconds RCU Tasks
Trace asynchronous callback batching for
<deci-seconds>: poll all this frequency
0: no polling (default)
+ thp_anon= [KNL]
+ Format: <size>,<size>[KMG]:<state>;<size>-<size>[KMG]:<state>
+ state is one of "always", "madvise", "never" or "inherit".
+ Control the default behavior of the system with respect
+ to anonymous transparent hugepages.
+ Can be used multiple times for multiple anon THP sizes.
+ See Documentation/admin-guide/mm/transhuge.rst for more
+ details.
+
threadirqs [KNL,EARLY]
Force threading of all interrupt handlers except those
marked explicitly IRQF_NO_THREAD.
it can be updated at runtime by writing to the
corresponding sysfs file.
+ workqueue.panic_on_stall=<uint>
+ Panic when workqueue stall is detected by
+ CONFIG_WQ_WATCHDOG. It sets the number times of the
+ stall to trigger panic.
+
+ The default is 0, which disables the panic on stall.
+
workqueue.cpu_intensive_thresh_us=
Per-cpu work items which run for longer than this
threshold are automatically considered CPU intensive