is selected automatically. Check
Documentation/kdump/kdump.txt for further details.
- crashkernel_low=size[KMG]
- [KNL, x86] parts under 4G.
-
crashkernel=range1:size1[,range2:size2,...][@offset]
[KNL] Same as above, but depends on the memory
in the running system. The syntax of range is
a memory unit (amount[KMG]). See also
Documentation/kdump/kdump.txt for an example.
+ crashkernel=size[KMG],high
+ [KNL, x86_64] range could be above 4G. Allow kernel
+ to allocate physical memory region from top, so could
+ be above 4G if system have more than 4G ram installed.
+ Otherwise memory region will be allocated below 4G, if
+ available.
+ It will be ignored if crashkernel=X is specified.
+ crashkernel=size[KMG],low
+ [KNL, x86_64] range under 4G. When crashkernel=X,high
+ is passed, kernel could allocate physical memory region
+ above 4G, that cause second kernel crash on system
+ that require some amount of low memory, e.g. swiotlb
+ requires at least 64M+32K low memory. Kernel would
+ try to allocate 72M below 4G automatically.
+ This one let user to specify own low range under 4G
+ for second kernel instead.
+ 0: to disable low allocation.
+ It will be ignored when crashkernel=X,high is not used
+ or memory reserved is below 4G.
+
cs89x0_dma= [HW,NET]
Format: <dma>
edd= [EDD]
Format: {"off" | "on" | "skip[mbr]"}
+ efi_no_storage_paranoia [EFI; X86]
+ Using this parameter you can use more than 50% of
+ your efi variable storage. Use this parameter only if
+ you are really sure that your UEFI does sane gc and
+ fulfills the spec otherwise your board may brick.
+
eisa_irq_edge= [PARISC,HW]
See header of drivers/parisc/eisa.c.
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.
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.
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.