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
depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
depends on MIGRATION
+#
+# If we have space for more page flags then we can enable additional
+# optimizations and functionality.
+#
+# Regular Sparsemem takes page flag bits for the sectionid if it does not
+# use a virtual memmap. Disable extended page flags for 32 bit platforms
+# that require the use of a sectionid in the page flags.
+#
+config PAGEFLAGS_EXTENDED
+ def_bool y
+ depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM
+
# 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