Kconfig revision 29c71111d0557385328211b130246a90f9223b46 
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#
116# SPARSEMEM_VMEMMAP uses a virtually mapped mem_map to optimise pfn_to_page
117# and page_to_pfn.  The most efficient option where kernel virtual space is
118# not under pressure.
119#
120config SPARSEMEM_VMEMMAP_ENABLE
121	def_bool n
122
123config SPARSEMEM_VMEMMAP
124	bool
125	depends on SPARSEMEM
126	default y if (SPARSEMEM_VMEMMAP_ENABLE)
127
128# eventually, we can have this option just 'select SPARSEMEM'
129config MEMORY_HOTPLUG
130	bool "Allow for memory hot-add"
131	depends on SPARSEMEM || X86_64_ACPI_NUMA
132	depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
133	depends on (IA64 || X86 || PPC64 || SUPERH)
134
135comment "Memory hotplug is currently incompatible with Software Suspend"
136	depends on SPARSEMEM && HOTPLUG && HIBERNATION
137
138config MEMORY_HOTPLUG_SPARSE
139	def_bool y
140	depends on SPARSEMEM && MEMORY_HOTPLUG
141
142# Heavily threaded applications may benefit from splitting the mm-wide
143# page_table_lock, so that faults on different parts of the user address
144# space can be handled with less contention: split it at this NR_CPUS.
145# Default to 4 for wider testing, though 8 might be more appropriate.
146# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
147# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
148#
149config SPLIT_PTLOCK_CPUS
150	int
151	default "4096" if ARM && !CPU_CACHE_VIPT
152	default "4096" if PARISC && !PA20
153	default "4096" if XEN
154	default "4"
155
156#
157# support for page migration
158#
159config MIGRATION
160	bool "Page migration"
161	def_bool y
162	depends on NUMA
163	help
164	  Allows the migration of the physical location of pages of processes
165	  while the virtual addresses are not changed. This is useful for
166	  example on NUMA systems to put pages nearer to the processors accessing
167	  the page.
168
169config RESOURCES_64BIT
170	bool "64 bit Memory and IO resources (EXPERIMENTAL)" if (!64BIT && EXPERIMENTAL)
171	default 64BIT
172	help
173	  This option allows memory and IO resources to be 64 bit.
174
175config ZONE_DMA_FLAG
176	int
177	default "0" if !ZONE_DMA
178	default "1"
179
180config BOUNCE
181	def_bool y
182	depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
183
184config NR_QUICK
185	int
186	depends on QUICKLIST
187	default "2" if (SUPERH && !SUPERH64)
188	default "1"
189
190config VIRT_TO_BUS
191	def_bool y
192	depends on !ARCH_NO_VIRT_TO_BUS
193