Kconfig 5.0 KB

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  1. config SELECT_MEMORY_MODEL
  2. def_bool y
  3. depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL
  4. choice
  5. prompt "Memory model"
  6. depends on SELECT_MEMORY_MODEL
  7. default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
  8. default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
  9. default FLATMEM_MANUAL
  10. config FLATMEM_MANUAL
  11. bool "Flat Memory"
  12. depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
  13. help
  14. This option allows you to change some of the ways that
  15. Linux manages its memory internally. Most users will
  16. only have one option here: FLATMEM. This is normal
  17. and a correct option.
  18. Some users of more advanced features like NUMA and
  19. memory hotplug may have different options here.
  20. DISCONTIGMEM is an more mature, better tested system,
  21. but is incompatible with memory hotplug and may suffer
  22. decreased performance over SPARSEMEM. If unsure between
  23. "Sparse Memory" and "Discontiguous Memory", choose
  24. "Discontiguous Memory".
  25. If unsure, choose this option (Flat Memory) over any other.
  26. config DISCONTIGMEM_MANUAL
  27. bool "Discontiguous Memory"
  28. depends on ARCH_DISCONTIGMEM_ENABLE
  29. help
  30. This option provides enhanced support for discontiguous
  31. memory systems, over FLATMEM. These systems have holes
  32. in their physical address spaces, and this option provides
  33. more efficient handling of these holes. However, the vast
  34. majority of hardware has quite flat address spaces, and
  35. can have degraded performance from extra overhead that
  36. this option imposes.
  37. Many NUMA configurations will have this as the only option.
  38. If unsure, choose "Flat Memory" over this option.
  39. config SPARSEMEM_MANUAL
  40. bool "Sparse Memory"
  41. depends on ARCH_SPARSEMEM_ENABLE
  42. help
  43. This will be the only option for some systems, including
  44. memory hotplug systems. This is normal.
  45. For many other systems, this will be an alternative to
  46. "Discontiguous Memory". This option provides some potential
  47. performance benefits, along with decreased code complexity,
  48. but it is newer, and more experimental.
  49. If unsure, choose "Discontiguous Memory" or "Flat Memory"
  50. over this option.
  51. endchoice
  52. config DISCONTIGMEM
  53. def_bool y
  54. depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
  55. config SPARSEMEM
  56. def_bool y
  57. depends on SPARSEMEM_MANUAL
  58. config FLATMEM
  59. def_bool y
  60. depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
  61. config FLAT_NODE_MEM_MAP
  62. def_bool y
  63. depends on !SPARSEMEM
  64. #
  65. # Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
  66. # to represent different areas of memory. This variable allows
  67. # those dependencies to exist individually.
  68. #
  69. config NEED_MULTIPLE_NODES
  70. def_bool y
  71. depends on DISCONTIGMEM || NUMA
  72. config HAVE_MEMORY_PRESENT
  73. def_bool y
  74. depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
  75. #
  76. # SPARSEMEM_EXTREME (which is the default) does some bootmem
  77. # allocations when memory_present() is called. If this cannot
  78. # be done on your architecture, select this option. However,
  79. # statically allocating the mem_section[] array can potentially
  80. # consume vast quantities of .bss, so be careful.
  81. #
  82. # This option will also potentially produce smaller runtime code
  83. # with gcc 3.4 and later.
  84. #
  85. config SPARSEMEM_STATIC
  86. def_bool n
  87. #
  88. # Architecture platforms which require a two level mem_section in SPARSEMEM
  89. # must select this option. This is usually for architecture platforms with
  90. # an extremely sparse physical address space.
  91. #
  92. config SPARSEMEM_EXTREME
  93. def_bool y
  94. depends on SPARSEMEM && !SPARSEMEM_STATIC
  95. # eventually, we can have this option just 'select SPARSEMEM'
  96. config MEMORY_HOTPLUG
  97. bool "Allow for memory hot-add"
  98. depends on SPARSEMEM || X86_64_ACPI_NUMA
  99. depends on HOTPLUG && !SOFTWARE_SUSPEND && ARCH_ENABLE_MEMORY_HOTPLUG
  100. depends on (IA64 || X86 || PPC64)
  101. comment "Memory hotplug is currently incompatible with Software Suspend"
  102. depends on SPARSEMEM && HOTPLUG && SOFTWARE_SUSPEND
  103. config MEMORY_HOTPLUG_SPARSE
  104. def_bool y
  105. depends on SPARSEMEM && MEMORY_HOTPLUG
  106. # Heavily threaded applications may benefit from splitting the mm-wide
  107. # page_table_lock, so that faults on different parts of the user address
  108. # space can be handled with less contention: split it at this NR_CPUS.
  109. # Default to 4 for wider testing, though 8 might be more appropriate.
  110. # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
  111. # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
  112. #
  113. config SPLIT_PTLOCK_CPUS
  114. int
  115. default "4096" if ARM && !CPU_CACHE_VIPT
  116. default "4096" if PARISC && !PA20
  117. default "4"
  118. #
  119. # support for page migration
  120. #
  121. config MIGRATION
  122. bool "Page migration"
  123. def_bool y
  124. depends on NUMA
  125. help
  126. Allows the migration of the physical location of pages of processes
  127. while the virtual addresses are not changed. This is useful for
  128. example on NUMA systems to put pages nearer to the processors accessing
  129. the page.
  130. config RESOURCES_64BIT
  131. bool "64 bit Memory and IO resources (EXPERIMENTAL)" if (!64BIT && EXPERIMENTAL)
  132. default 64BIT
  133. help
  134. This option allows memory and IO resources to be 64 bit.
  135. config ZONE_DMA_FLAG
  136. int
  137. default "0" if !ZONE_DMA
  138. default "1"