Kconfig 6.3 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 the 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. config HAVE_GET_USER_PAGES_FAST
  65. bool
  66. #
  67. # Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
  68. # to represent different areas of memory. This variable allows
  69. # those dependencies to exist individually.
  70. #
  71. config NEED_MULTIPLE_NODES
  72. def_bool y
  73. depends on DISCONTIGMEM || NUMA
  74. config HAVE_MEMORY_PRESENT
  75. def_bool y
  76. depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
  77. #
  78. # SPARSEMEM_EXTREME (which is the default) does some bootmem
  79. # allocations when memory_present() is called. If this cannot
  80. # be done on your architecture, select this option. However,
  81. # statically allocating the mem_section[] array can potentially
  82. # consume vast quantities of .bss, so be careful.
  83. #
  84. # This option will also potentially produce smaller runtime code
  85. # with gcc 3.4 and later.
  86. #
  87. config SPARSEMEM_STATIC
  88. def_bool n
  89. #
  90. # Architecture platforms which require a two level mem_section in SPARSEMEM
  91. # must select this option. This is usually for architecture platforms with
  92. # an extremely sparse physical address space.
  93. #
  94. config SPARSEMEM_EXTREME
  95. def_bool y
  96. depends on SPARSEMEM && !SPARSEMEM_STATIC
  97. config SPARSEMEM_VMEMMAP_ENABLE
  98. def_bool n
  99. config SPARSEMEM_VMEMMAP
  100. bool "Sparse Memory virtual memmap"
  101. depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
  102. default y
  103. help
  104. SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
  105. pfn_to_page and page_to_pfn operations. This is the most
  106. efficient option when sufficient kernel resources are available.
  107. # eventually, we can have this option just 'select SPARSEMEM'
  108. config MEMORY_HOTPLUG
  109. bool "Allow for memory hot-add"
  110. depends on SPARSEMEM || X86_64_ACPI_NUMA
  111. depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
  112. depends on (IA64 || X86 || PPC64 || SUPERH || S390)
  113. comment "Memory hotplug is currently incompatible with Software Suspend"
  114. depends on SPARSEMEM && HOTPLUG && HIBERNATION
  115. config MEMORY_HOTPLUG_SPARSE
  116. def_bool y
  117. depends on SPARSEMEM && MEMORY_HOTPLUG
  118. config MEMORY_HOTREMOVE
  119. bool "Allow for memory hot remove"
  120. depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
  121. depends on MIGRATION
  122. #
  123. # If we have space for more page flags then we can enable additional
  124. # optimizations and functionality.
  125. #
  126. # Regular Sparsemem takes page flag bits for the sectionid if it does not
  127. # use a virtual memmap. Disable extended page flags for 32 bit platforms
  128. # that require the use of a sectionid in the page flags.
  129. #
  130. config PAGEFLAGS_EXTENDED
  131. def_bool y
  132. depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM
  133. # Heavily threaded applications may benefit from splitting the mm-wide
  134. # page_table_lock, so that faults on different parts of the user address
  135. # space can be handled with less contention: split it at this NR_CPUS.
  136. # Default to 4 for wider testing, though 8 might be more appropriate.
  137. # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
  138. # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
  139. #
  140. config SPLIT_PTLOCK_CPUS
  141. int
  142. default "4096" if ARM && !CPU_CACHE_VIPT
  143. default "4096" if PARISC && !PA20
  144. default "4"
  145. #
  146. # support for page migration
  147. #
  148. config MIGRATION
  149. bool "Page migration"
  150. def_bool y
  151. depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
  152. help
  153. Allows the migration of the physical location of pages of processes
  154. while the virtual addresses are not changed. This is useful for
  155. example on NUMA systems to put pages nearer to the processors accessing
  156. the page.
  157. config RESOURCES_64BIT
  158. bool "64 bit Memory and IO resources (EXPERIMENTAL)" if (!64BIT && EXPERIMENTAL)
  159. default 64BIT
  160. help
  161. This option allows memory and IO resources to be 64 bit.
  162. config ZONE_DMA_FLAG
  163. int
  164. default "0" if !ZONE_DMA
  165. default "1"
  166. config BOUNCE
  167. def_bool y
  168. depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
  169. config NR_QUICK
  170. int
  171. depends on QUICKLIST
  172. default "2" if SUPERH || AVR32
  173. default "1"
  174. config VIRT_TO_BUS
  175. def_bool y
  176. depends on !ARCH_NO_VIRT_TO_BUS
  177. config MMU_NOTIFIER
  178. bool