diff options
Diffstat (limited to 'Documentation/kernel-parameters.txt')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 93 |
1 files changed, 77 insertions, 16 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 47bb23c22b1..c3bfacb9291 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -44,6 +44,8 @@ parameter is applicable: AVR32 AVR32 architecture is enabled. AX25 Appropriate AX.25 support is enabled. BLACKFIN Blackfin architecture is enabled. + CLK Common clock infrastructure is enabled. + CMA Contiguous Memory Area support is enabled. DRM Direct Rendering Management support is enabled. DYNAMIC_DEBUG Build in debug messages and enable them at runtime EDD BIOS Enhanced Disk Drive Services (EDD) is enabled @@ -320,6 +322,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. on: enable for both 32- and 64-bit processes off: disable for both 32- and 64-bit processes + alloc_snapshot [FTRACE] + Allocate the ftrace snapshot buffer on boot up when the + main buffer is allocated. This is handy if debugging + and you need to use tracing_snapshot() on boot up, and + do not want to use tracing_snapshot_alloc() as it needs + to be done where GFP_KERNEL allocations are allowed. + amd_iommu= [HW,X86-64] Pass parameters to the AMD IOMMU driver in the system. Possible values are: @@ -465,6 +474,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. cio_ignore= [S390] See Documentation/s390/CommonIO for details. + clk_ignore_unused + [CLK] + Keep all clocks already enabled by bootloader on, + even if no driver has claimed them. This is useful + for debug and development, but should not be + needed on a platform with proper driver support. + For more information, see Documentation/clk.txt. clock= [BUGS=X86-32, HW] gettimeofday clocksource override. [Deprecated] @@ -774,19 +790,31 @@ bytes respectively. Such letter suffixes can also be entirely omitted. (mmio) or 32-bit (mmio32). The options are the same as for ttyS, above. - earlyprintk= [X86,SH,BLACKFIN] + earlyprintk= [X86,SH,BLACKFIN,ARM] earlyprintk=vga earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] + earlyprintk=serial[,0x...[,baudrate]] earlyprintk=ttySn[,baudrate] earlyprintk=dbgp[debugController#] + earlyprintk is useful when the kernel crashes before + the normal console is initialized. It is not enabled by + default because it has some cosmetic problems. + Append ",keep" to not disable it when the real console takes over. Only vga or serial or usb debug port at a time. - Currently only ttyS0 and ttyS1 are supported. + Currently only ttyS0 and ttyS1 may be specified by + name. Other I/O ports may be explicitly specified + on some architectures (x86 and arm at least) by + replacing ttySn with an I/O port address, like this: + earlyprintk=serial,0x1008,115200 + You can find the port for a given device in + /proc/tty/driver/serial: + 2: uart:ST16650V2 port:00001008 irq:18 ... Interaction with the standard serial driver is not very good. @@ -1662,7 +1690,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. module.sig_enforce [KNL] When CONFIG_MODULE_SIG is set, this means that modules without (valid) signatures will fail to load. - Note that if CONFIG_MODULE_SIG_ENFORCE is set, that + Note that if CONFIG_MODULE_SIG_FORCE is set, that is always true, so this option does nothing. mousedev.tap_time= @@ -1950,6 +1978,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Valid arguments: on, off Default: on + nohz_full= [KNL,BOOT] + In kernels built with CONFIG_NO_HZ_FULL=y, set + the specified list of CPUs whose tick will be stopped + whenever possible. The boot CPU will be forced outside + the range to maintain the timekeeping. + The CPUs in this range must also be included in the + rcu_nocbs= set. + noiotrap [SH] Disables trapped I/O port accesses. noirqdebug [X86-32] Disables the code which attempts to detect and @@ -2011,8 +2047,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives - noresidual [PPC] Don't use residual data on PReP machines. - nordrand [X86] Disable the direct use of the RDRAND instruction even if it is supported by the processor. RDRAND is still available to user @@ -2498,9 +2532,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. In kernels built with CONFIG_RCU_NOCB_CPU=y, set the specified list of CPUs to be no-callback CPUs. Invocation of these CPUs' RCU callbacks will - be offloaded to "rcuoN" kthreads created for - that purpose. This reduces OS jitter on the + be offloaded to "rcuox/N" kthreads created for + that purpose, where "x" is "b" for RCU-bh, "p" + for RCU-preempt, and "s" for RCU-sched, and "N" + is the CPU number. This reduces OS jitter on the offloaded CPUs, which can be useful for HPC and + real-time workloads. It can also improve energy efficiency for asymmetric multiprocessors. @@ -2524,6 +2561,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. leaf rcu_node structure. Useful for very large systems. + rcutree.jiffies_till_first_fqs= [KNL,BOOT] + Set delay from grace-period initialization to + first attempt to force quiescent states. + Units are jiffies, minimum value is zero, + and maximum value is HZ. + + rcutree.jiffies_till_next_fqs= [KNL,BOOT] + Set delay between subsequent attempts to force + quiescent states. Units are jiffies, minimum + value is one, and maximum value is HZ. + rcutree.qhimark= [KNL,BOOT] Set threshold of queued RCU callbacks over which batch limiting is disabled. @@ -2538,16 +2586,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. rcutree.rcu_cpu_stall_timeout= [KNL,BOOT] Set timeout for RCU CPU stall warning messages. - rcutree.jiffies_till_first_fqs= [KNL,BOOT] - Set delay from grace-period initialization to - first attempt to force quiescent states. - Units are jiffies, minimum value is zero, - and maximum value is HZ. + rcutree.rcu_idle_gp_delay= [KNL,BOOT] + Set wakeup interval for idle CPUs that have + RCU callbacks (RCU_FAST_NO_HZ=y). - rcutree.jiffies_till_next_fqs= [KNL,BOOT] - Set delay between subsequent attempts to force - quiescent states. Units are jiffies, minimum - value is one, and maximum value is HZ. + rcutree.rcu_idle_lazy_gp_delay= [KNL,BOOT] + Set wakeup interval for idle CPUs that have + only "lazy" RCU callbacks (RCU_FAST_NO_HZ=y). + Lazy RCU callbacks are those which RCU can + prove do nothing more than free memory. rcutorture.fqs_duration= [KNL,BOOT] Set duration of force_quiescent_state bursts. @@ -2700,6 +2747,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Useful for devices that are detected asynchronously (e.g. USB and MMC devices). + rproc_mem=nn[KMG][@address] + [KNL,ARM,CMA] Remoteproc physical memory block. + Memory area to be used by remote processor image, + managed by CMA. + rw [KNL] Mount root device read-write on boot S [KNL] Run init in single mode @@ -3259,6 +3311,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted. or other driver-specific files in the Documentation/watchdog/ directory. + workqueue.disable_numa + By default, all work items queued to unbound + workqueues are affine to the NUMA nodes they're + issued on, which results in better behavior in + general. If NUMA affinity needs to be disabled for + whatever reason, this option can be used. Note + that this also can be controlled per-workqueue for + workqueues visible under /sys/bus/workqueue/. + x2apic_phys [X86-64,APIC] Use x2apic physical mode instead of default x2apic cluster mode on platforms supporting x2apic. |