+config SELECT_MEMORY_MODEL
+ def_bool y
+ depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL
+
choice
prompt "Memory model"
- default DISCONTIGMEM if ARCH_DISCONTIGMEM_DEFAULT
- default FLATMEM
+ depends on SELECT_MEMORY_MODEL
+ default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
+ default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
+ default FLATMEM_MANUAL
-config FLATMEM
+config FLATMEM_MANUAL
bool "Flat Memory"
- depends on !ARCH_DISCONTIGMEM_ENABLE || ARCH_FLATMEM_ENABLE
+ depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
help
This option allows you to change some of the ways that
Linux manages its memory internally. Most users will
only have one option here: FLATMEM. This is normal
and a correct option.
- If unsure, choose this option over any other.
+ Some users of more advanced features like NUMA and
+ memory hotplug may have different options here.
+ DISCONTIGMEM is an more mature, better tested system,
+ but is incompatible with memory hotplug and may suffer
+ decreased performance over SPARSEMEM. If unsure between
+ "Sparse Memory" and "Discontiguous Memory", choose
+ "Discontiguous Memory".
-config DISCONTIGMEM
- bool "Discontigious Memory"
+ If unsure, choose this option (Flat Memory) over any other.
+
+config DISCONTIGMEM_MANUAL
+ bool "Discontiguous Memory"
depends on ARCH_DISCONTIGMEM_ENABLE
help
+ This option provides enhanced support for discontiguous
+ memory systems, over FLATMEM. These systems have holes
+ 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 the extra overhead that
+ this option imposes.
+
+ Many NUMA configurations will have this as the only option.
+
If unsure, choose "Flat Memory" over this option.
+config SPARSEMEM_MANUAL
+ bool "Sparse Memory"
+ depends on ARCH_SPARSEMEM_ENABLE
+ help
+ This will be the only option for some systems, including
+ memory hotplug systems. This is normal.
+
+ For many other systems, this will be an alternative to
+ "Discontiguous Memory". This option provides some potential
+ performance benefits, along with decreased code complexity,
+ but it is newer, and more experimental.
+
+ If unsure, choose "Discontiguous Memory" or "Flat Memory"
+ over this option.
+
endchoice
+config DISCONTIGMEM
+ def_bool y
+ depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
+
+config SPARSEMEM
+ def_bool y
+ depends on SPARSEMEM_MANUAL
+
+config FLATMEM
+ def_bool y
+ depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
+
+config FLAT_NODE_MEM_MAP
+ def_bool y
+ depends on !SPARSEMEM
+
#
# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
# to represent different areas of memory. This variable allows
config NEED_MULTIPLE_NODES
def_bool y
depends on DISCONTIGMEM || NUMA
+
+config HAVE_MEMORY_PRESENT
+ def_bool y
+ depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
+
+#
+# SPARSEMEM_EXTREME (which is the default) does some bootmem
+# allocations when memory_present() is called. If this cannot
+# be done on your architecture, select this option. However,
+# statically allocating the mem_section[] array can potentially
+# consume vast quantities of .bss, so be careful.
+#
+# This option will also potentially produce smaller runtime code
+# with gcc 3.4 and later.
+#
+config SPARSEMEM_STATIC
+ bool
+
+#
+# Architecture platforms which require a two level mem_section in SPARSEMEM
+# must select this option. This is usually for architecture platforms with
+# an extremely sparse physical address space.
+#
+config SPARSEMEM_EXTREME
+ def_bool y
+ depends on SPARSEMEM && !SPARSEMEM_STATIC
+
+config SPARSEMEM_VMEMMAP_ENABLE
+ bool
+
+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"
+ depends on SPARSEMEM || X86_64_ACPI_NUMA
+ depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
+ depends on (IA64 || X86 || PPC64 || SUPERH || S390)
+
+comment "Memory hotplug is currently incompatible with Software Suspend"
+ depends on SPARSEMEM && HOTPLUG && HIBERNATION
+
+config MEMORY_HOTPLUG_SPARSE
+ 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
+
+#
+# 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.
+# Default to 4 for wider testing, though 8 might be more appropriate.
+# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
+# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
+#
+config SPLIT_PTLOCK_CPUS
+ int
+ default "4096" if ARM && !CPU_CACHE_VIPT
+ default "4096" if PARISC && !PA20
+ default "4"
+
+#
+# support for page migration
+#
+config MIGRATION
+ bool "Page migration"
+ def_bool y
+ depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
+ help
+ Allows the migration of the physical location of pages of processes
+ while the virtual addresses are not changed. This is useful for
+ example on NUMA systems to put pages nearer to the processors accessing
+ the page.
+
+config PHYS_ADDR_T_64BIT
+ def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
+
+config ZONE_DMA_FLAG
+ int
+ default "0" if !ZONE_DMA
+ default "1"
+
+config BOUNCE
+ def_bool y
+ depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
+
+config NR_QUICK
+ int
+ depends on QUICKLIST
+ default "2" if SUPERH || AVR32
+ default "1"
+
+config VIRT_TO_BUS
+ def_bool y
+ depends on !ARCH_NO_VIRT_TO_BUS
+
+config UNEVICTABLE_LRU
+ bool "Add LRU list to track non-evictable pages"
+ default y
+ help
+ Keeps unevictable pages off of the active and inactive pageout
+ lists, so kswapd will not waste CPU time or have its balancing
+ algorithms thrown off by scanning these pages. Selecting this
+ will use one page flag and increase the code size a little,
+ say Y unless you know what you are doing.
+
+config HAVE_MLOCK
+ bool
+ default y if MMU=y
+
+config HAVE_MLOCKED_PAGE_BIT
+ bool
+ default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
+
+config MMU_NOTIFIER
+ bool
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