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
+config SPARSEMEM_VMEMMAP_ENABLE
+ def_bool n
+
+config SPARSEMEM_VMEMMAP
+ 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
bool "Allow for memory hot-add"
def_bool y
depends on SPARSEMEM && MEMORY_HOTPLUG
+config MEMORY_HOTREMOVE
+ bool "Allow for memory hot remove"
+ depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
+ depends on MIGRATION
+
# Heavily threaded applications may benefit from splitting the mm-wide
# page_table_lock, so that faults on different parts of the user address
# space can be handled with less contention: split it at this NR_CPUS.
config NR_QUICK
int
depends on QUICKLIST
- default "2" if (SUPERH && !SUPERH64)
+ default "2" if SUPERH
default "1"
config VIRT_TO_BUS