1config SELECT_MEMORY_MODEL 2 def_bool y 3 depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL 4 5choice 6 prompt "Memory model" 7 depends on SELECT_MEMORY_MODEL 8 default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT 9 default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT 10 default FLATMEM_MANUAL 11 12config FLATMEM_MANUAL 13 bool "Flat Memory" 14 depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE 15 help 16 This option allows you to change some of the ways that 17 Linux manages its memory internally. Most users will 18 only have one option here: FLATMEM. This is normal 19 and a correct option. 20 21 Some users of more advanced features like NUMA and 22 memory hotplug may have different options here. 23 DISCONTIGMEM is an more mature, better tested system, 24 but is incompatible with memory hotplug and may suffer 25 decreased performance over SPARSEMEM. If unsure between 26 "Sparse Memory" and "Discontiguous Memory", choose 27 "Discontiguous Memory". 28 29 If unsure, choose this option (Flat Memory) over any other. 30 31config DISCONTIGMEM_MANUAL 32 bool "Discontiguous Memory" 33 depends on ARCH_DISCONTIGMEM_ENABLE 34 help 35 This option provides enhanced support for discontiguous 36 memory systems, over FLATMEM. These systems have holes 37 in their physical address spaces, and this option provides 38 more efficient handling of these holes. However, the vast 39 majority of hardware has quite flat address spaces, and 40 can have degraded performance from extra overhead that 41 this option imposes. 42 43 Many NUMA configurations will have this as the only option. 44 45 If unsure, choose "Flat Memory" over this option. 46 47config SPARSEMEM_MANUAL 48 bool "Sparse Memory" 49 depends on ARCH_SPARSEMEM_ENABLE 50 help 51 This will be the only option for some systems, including 52 memory hotplug systems. This is normal. 53 54 For many other systems, this will be an alternative to 55 "Discontiguous Memory". This option provides some potential 56 performance benefits, along with decreased code complexity, 57 but it is newer, and more experimental. 58 59 If unsure, choose "Discontiguous Memory" or "Flat Memory" 60 over this option. 61 62endchoice 63 64config DISCONTIGMEM 65 def_bool y 66 depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL 67 68config SPARSEMEM 69 def_bool y 70 depends on SPARSEMEM_MANUAL 71 72config FLATMEM 73 def_bool y 74 depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL 75 76config FLAT_NODE_MEM_MAP 77 def_bool y 78 depends on !SPARSEMEM 79 80# 81# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's 82# to represent different areas of memory. This variable allows 83# those dependencies to exist individually. 84# 85config NEED_MULTIPLE_NODES 86 def_bool y 87 depends on DISCONTIGMEM || NUMA 88 89config HAVE_MEMORY_PRESENT 90 def_bool y 91 depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM 92 93# 94# SPARSEMEM_EXTREME (which is the default) does some bootmem 95# allocations when memory_present() is called. If this cannot 96# be done on your architecture, select this option. However, 97# statically allocating the mem_section[] array can potentially 98# consume vast quantities of .bss, so be careful. 99# 100# This option will also potentially produce smaller runtime code 101# with gcc 3.4 and later. 102# 103config SPARSEMEM_STATIC 104 def_bool n 105 106# 107# Architecture platforms which require a two level mem_section in SPARSEMEM 108# must select this option. This is usually for architecture platforms with 109# an extremely sparse physical address space. 110# 111config SPARSEMEM_EXTREME 112 def_bool y 113 depends on SPARSEMEM && !SPARSEMEM_STATIC 114 115# eventually, we can have this option just 'select SPARSEMEM' 116config MEMORY_HOTPLUG 117 bool "Allow for memory hot-add" 118 depends on SPARSEMEM || X86_64_ACPI_NUMA 119 depends on HOTPLUG && !SOFTWARE_SUSPEND && ARCH_ENABLE_MEMORY_HOTPLUG 120 depends on (IA64 || X86 || PPC64) 121 122comment "Memory hotplug is currently incompatible with Software Suspend" 123 depends on SPARSEMEM && HOTPLUG && SOFTWARE_SUSPEND 124 125config MEMORY_HOTPLUG_SPARSE 126 def_bool y 127 depends on SPARSEMEM && MEMORY_HOTPLUG 128 129# Heavily threaded applications may benefit from splitting the mm-wide 130# page_table_lock, so that faults on different parts of the user address 131# space can be handled with less contention: split it at this NR_CPUS. 132# Default to 4 for wider testing, though 8 might be more appropriate. 133# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock. 134# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes. 135# 136config SPLIT_PTLOCK_CPUS 137 int 138 default "4096" if ARM && !CPU_CACHE_VIPT 139 default "4096" if PARISC && !PA20 140 default "4" 141 142# 143# support for page migration 144# 145config MIGRATION 146 bool "Page migration" 147 def_bool y 148 depends on NUMA 149 help 150 Allows the migration of the physical location of pages of processes 151 while the virtual addresses are not changed. This is useful for 152 example on NUMA systems to put pages nearer to the processors accessing 153 the page. 154 155config RESOURCES_64BIT 156 bool "64 bit Memory and IO resources (EXPERIMENTAL)" if (!64BIT && EXPERIMENTAL) 157 default 64BIT 158 help 159 This option allows memory and IO resources to be 64 bit. 160 161config ZONE_DMA_FLAG 162 int 163 default "0" if !ZONE_DMA 164 default "1" 165 166config NR_QUICK 167 int 168 depends on QUICKLIST 169 default "2" if (SUPERH && !SUPERH64) 170 default "1" 171