in their physical address spaces, and this option provides
more efficient handling of these holes. However, the vast
majority of hardware has quite flat address spaces, and
- can have degraded performance from extra overhead that
+ can have degraded performance from the extra overhead that
this option imposes.
Many NUMA configurations will have this as the only option.
def_bool y
depends on SPARSEMEM && !SPARSEMEM_STATIC
-#
-# SPARSEMEM_VMEMMAP uses a virtually mapped mem_map to optimise pfn_to_page
-# and page_to_pfn. The most efficient option where kernel virtual space is
-# not under pressure.
-#
config SPARSEMEM_VMEMMAP_ENABLE
def_bool n
config SPARSEMEM_VMEMMAP
- bool
- depends on SPARSEMEM
- default y if (SPARSEMEM_VMEMMAP_ENABLE)
+ bool "Sparse Memory virtual memmap"
+ depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
+ default y
+ help
+ SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
+ pfn_to_page and page_to_pfn operations. This is the most
+ efficient option when sufficient kernel resources are available.
# eventually, we can have this option just 'select SPARSEMEM'
config MEMORY_HOTPLUG
config NR_QUICK
int
depends on QUICKLIST
- default "2" if (SUPERH && !SUPERH64)
+ default "2" if SUPERH
default "1"
config VIRT_TO_BUS