The keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
-config SMP
- bool "Symmetric multi-processing support"
- default n
- depends on BROKEN
- help
- This option enables UML SMP support.
- It is NOT related to having a real SMP box. Not directly, at least.
-
- UML implements virtual SMP by allowing as many processes to run
- simultaneously on the host as there are virtual processors configured.
-
- Obviously, if the host is a uniprocessor, those processes will
- timeshare, but, inside UML, will appear to be running simultaneously.
- If the host is a multiprocessor, then UML processes may run
- simultaneously, depending on the host scheduler.
-
- This, however, is supported only in TT mode. So, if you use the SKAS
- patch on your host, switching to TT mode and enabling SMP usually
- gives you worse performances.
- Also, since the support for SMP has been under-developed, there could
- be some bugs being exposed by enabling SMP.
-
- If you don't know what to do, say N.
-
-config NR_CPUS
- int "Maximum number of CPUs (2-32)"
- range 2 32
- depends on SMP
- default "32"
-
-config HIGHMEM
- bool "Highmem support"
- depends on !64BIT && BROKEN
- default n
- help
- This was used to allow UML to run with big amounts of memory.
- Currently it is unstable, so if unsure say N.
-
- To use big amounts of memory, it is recommended enable static
- linking (i.e. CONFIG_STATIC_LINK) - this should allow the
- guest to use up to 2.75G of memory.
-
config KERNEL_STACK_ORDER
int "Kernel stack size order"
default 1 if 64BIT
config NO_DMA
def_bool y
+
+config PGTABLE_LEVELS
+ int
+ default 3 if 3_LEVEL_PGTABLES
+ default 2