config SELECT_MEMORY_MODEL
  	def_bool y
  	depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL

  choice
  	prompt "Memory model"

  	depends on SELECT_MEMORY_MODEL
  	default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT

  	default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT

  	default FLATMEM_MANUAL

  config FLATMEM_MANUAL

  	bool "Flat Memory"

  	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.

  	  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".
  
  	  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 (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || 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
  # those dependencies to exist individually.
  #
  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_ALLOC_MEM_MAP_TOGETHER
  	def_bool y
  	depends on SPARSEMEM && X86_64

  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.

  config HAVE_MEMBLOCK
  	boolean

  config HAVE_MEMBLOCK_NODE_MAP
  	boolean

  config ARCH_DISCARD_MEMBLOCK
  	boolean

  config NO_BOOTMEM
  	boolean

  # 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 && ARCH_ENABLE_MEMORY_HOTPLUG

  	depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)

  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 || !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.

  # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.

  #
  config SPLIT_PTLOCK_CPUS
  	int

  	default "999999" if ARM && !CPU_CACHE_VIPT
  	default "999999" if PARISC && !PA20
  	default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC

  	default "4"

  
  #

  # support for memory compaction
  config COMPACTION
  	bool "Allow for memory compaction"
  	select MIGRATION

  	depends on MMU

  	help
  	  Allows the compaction of memory for the allocation of huge pages.
  
  #

  # support for page migration
  #
  config MIGRATION

  	bool "Page migration"

  	def_bool y

  	depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION

  	help
  	  Allows the migration of the physical location of pages of processes

  	  while the virtual addresses are not changed. This is useful in
  	  two situations. The first is on NUMA systems to put pages nearer
  	  to the processors accessing. The second is when allocating huge
  	  pages as migration can relocate pages to satisfy a huge page
  	  allocation instead of reclaiming.

  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 AVR32

  	default "1"

  
  config VIRT_TO_BUS
  	def_bool y
  	depends on !ARCH_NO_VIRT_TO_BUS

  
  config MMU_NOTIFIER
  	bool

  config KSM
  	bool "Enable KSM for page merging"
  	depends on MMU
  	help
  	  Enable Kernel Samepage Merging: KSM periodically scans those areas
  	  of an application's address space that an app has advised may be
  	  mergeable.  When it finds pages of identical content, it replaces

  	  the many instances by a single page with that content, so

  	  saving memory until one or another app needs to modify the content.
  	  Recommended for use with KVM, or with other duplicative applications.

  	  See Documentation/vm/ksm.txt for more information: KSM is inactive
  	  until a program has madvised that an area is MADV_MERGEABLE, and
  	  root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).

  config DEFAULT_MMAP_MIN_ADDR
          int "Low address space to protect from user allocation"

  	depends on MMU

          default 4096
          help
  	  This is the portion of low virtual memory which should be protected
  	  from userspace allocation.  Keeping a user from writing to low pages
  	  can help reduce the impact of kernel NULL pointer bugs.
  
  	  For most ia64, ppc64 and x86 users with lots of address space
  	  a value of 65536 is reasonable and should cause no problems.
  	  On arm and other archs it should not be higher than 32768.

  	  Programs which use vm86 functionality or have some need to map
  	  this low address space will need CAP_SYS_RAWIO or disable this
  	  protection by setting the value to 0.

  
  	  This value can be changed after boot using the
  	  /proc/sys/vm/mmap_min_addr tunable.

  config ARCH_SUPPORTS_MEMORY_FAILURE
  	bool

  config MEMORY_FAILURE
  	depends on MMU

  	depends on ARCH_SUPPORTS_MEMORY_FAILURE

  	bool "Enable recovery from hardware memory errors"
  	help
  	  Enables code to recover from some memory failures on systems
  	  with MCA recovery. This allows a system to continue running
  	  even when some of its memory has uncorrected errors. This requires
  	  special hardware support and typically ECC memory.

  config HWPOISON_INJECT

  	tristate "HWPoison pages injector"

  	depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS

  	select PROC_PAGE_MONITOR

  config NOMMU_INITIAL_TRIM_EXCESS
  	int "Turn on mmap() excess space trimming before booting"
  	depends on !MMU
  	default 1
  	help
  	  The NOMMU mmap() frequently needs to allocate large contiguous chunks
  	  of memory on which to store mappings, but it can only ask the system
  	  allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
  	  more than it requires.  To deal with this, mmap() is able to trim off
  	  the excess and return it to the allocator.
  
  	  If trimming is enabled, the excess is trimmed off and returned to the
  	  system allocator, which can cause extra fragmentation, particularly
  	  if there are a lot of transient processes.
  
  	  If trimming is disabled, the excess is kept, but not used, which for
  	  long-term mappings means that the space is wasted.
  
  	  Trimming can be dynamically controlled through a sysctl option
  	  (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
  	  excess pages there must be before trimming should occur, or zero if
  	  no trimming is to occur.
  
  	  This option specifies the initial value of this option.  The default
  	  of 1 says that all excess pages should be trimmed.
  
  	  See Documentation/nommu-mmap.txt for more information.

  config TRANSPARENT_HUGEPAGE

  	bool "Transparent Hugepage Support"

  	depends on X86 && MMU

  	select COMPACTION

  	help
  	  Transparent Hugepages allows the kernel to use huge pages and
  	  huge tlb transparently to the applications whenever possible.
  	  This feature can improve computing performance to certain
  	  applications by speeding up page faults during memory
  	  allocation, by reducing the number of tlb misses and by speeding
  	  up the pagetable walking.
  
  	  If memory constrained on embedded, you may want to say N.

  choice
  	prompt "Transparent Hugepage Support sysfs defaults"
  	depends on TRANSPARENT_HUGEPAGE
  	default TRANSPARENT_HUGEPAGE_ALWAYS
  	help
  	  Selects the sysfs defaults for Transparent Hugepage Support.
  
  	config TRANSPARENT_HUGEPAGE_ALWAYS
  		bool "always"
  	help
  	  Enabling Transparent Hugepage always, can increase the
  	  memory footprint of applications without a guaranteed
  	  benefit but it will work automatically for all applications.
  
  	config TRANSPARENT_HUGEPAGE_MADVISE
  		bool "madvise"
  	help
  	  Enabling Transparent Hugepage madvise, will only provide a
  	  performance improvement benefit to the applications using
  	  madvise(MADV_HUGEPAGE) but it won't risk to increase the
  	  memory footprint of applications without a guaranteed
  	  benefit.
  endchoice

  #
  # UP and nommu archs use km based percpu allocator
  #
  config NEED_PER_CPU_KM
  	depends on !SMP
  	bool
  	default y

  
  config CLEANCACHE
  	bool "Enable cleancache driver to cache clean pages if tmem is present"
  	default n
  	help
  	  Cleancache can be thought of as a page-granularity victim cache
  	  for clean pages that the kernel's pageframe replacement algorithm
  	  (PFRA) would like to keep around, but can't since there isn't enough
  	  memory.  So when the PFRA "evicts" a page, it first attempts to use

  	  cleancache code to put the data contained in that page into

  	  "transcendent memory", memory that is not directly accessible or
  	  addressable by the kernel and is of unknown and possibly
  	  time-varying size.  And when a cleancache-enabled
  	  filesystem wishes to access a page in a file on disk, it first
  	  checks cleancache to see if it already contains it; if it does,
  	  the page is copied into the kernel and a disk access is avoided.
  	  When a transcendent memory driver is available (such as zcache or
  	  Xen transcendent memory), a significant I/O reduction
  	  may be achieved.  When none is available, all cleancache calls
  	  are reduced to a single pointer-compare-against-NULL resulting
  	  in a negligible performance hit.
  
  	  If unsure, say Y to enable cleancache