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Dave Hansene1785e82005-06-23 00:07:49 -07001config SELECT_MEMORY_MODEL
2 def_bool y
3 depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL
4
Dave Hansen3a9da762005-06-23 00:07:42 -07005choice
6 prompt "Memory model"
Dave Hansene1785e82005-06-23 00:07:49 -07007 depends on SELECT_MEMORY_MODEL
8 default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
Andy Whitcroftd41dee32005-06-23 00:07:54 -07009 default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
Dave Hansene1785e82005-06-23 00:07:49 -070010 default FLATMEM_MANUAL
Dave Hansen3a9da762005-06-23 00:07:42 -070011
Dave Hansene1785e82005-06-23 00:07:49 -070012config FLATMEM_MANUAL
Dave Hansen3a9da762005-06-23 00:07:42 -070013 bool "Flat Memory"
Anton Blanchardc898ec12006-01-06 00:12:07 -080014 depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
Dave Hansen3a9da762005-06-23 00:07:42 -070015 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
Andy Whitcroftd41dee32005-06-23 00:07:54 -070021 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.
Dave Hansen3a9da762005-06-23 00:07:42 -070030
Dave Hansene1785e82005-06-23 00:07:49 -070031config DISCONTIGMEM_MANUAL
Dave Hansenf3519f92005-09-16 19:27:54 -070032 bool "Discontiguous Memory"
Dave Hansen3a9da762005-06-23 00:07:42 -070033 depends on ARCH_DISCONTIGMEM_ENABLE
34 help
Dave Hansen785dcd42005-06-23 00:07:50 -070035 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
Philipp Marekad3d0a32007-10-20 02:46:58 +020040 can have degraded performance from the extra overhead that
Dave Hansen785dcd42005-06-23 00:07:50 -070041 this option imposes.
42
43 Many NUMA configurations will have this as the only option.
44
Dave Hansen3a9da762005-06-23 00:07:42 -070045 If unsure, choose "Flat Memory" over this option.
46
Andy Whitcroftd41dee32005-06-23 00:07:54 -070047config 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
Dave Hansenf3519f92005-09-16 19:27:54 -070055 "Discontiguous Memory". This option provides some potential
Andy Whitcroftd41dee32005-06-23 00:07:54 -070056 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
Dave Hansen3a9da762005-06-23 00:07:42 -070062endchoice
63
Dave Hansene1785e82005-06-23 00:07:49 -070064config DISCONTIGMEM
65 def_bool y
66 depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
67
Andy Whitcroftd41dee32005-06-23 00:07:54 -070068config SPARSEMEM
69 def_bool y
Russell King1a83e172009-10-26 16:50:12 -070070 depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL
Andy Whitcroftd41dee32005-06-23 00:07:54 -070071
Dave Hansene1785e82005-06-23 00:07:49 -070072config FLATMEM
73 def_bool y
Andy Whitcroftd41dee32005-06-23 00:07:54 -070074 depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
75
76config FLAT_NODE_MEM_MAP
77 def_bool y
78 depends on !SPARSEMEM
Dave Hansene1785e82005-06-23 00:07:49 -070079
Dave Hansen93b75042005-06-23 00:07:47 -070080#
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
Andy Whitcroftaf705362005-06-23 00:07:53 -070088
89config HAVE_MEMORY_PRESENT
90 def_bool y
Andy Whitcroftd41dee32005-06-23 00:07:54 -070091 depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
Bob Picco802f1922005-09-03 15:54:26 -070092
93#
Bob Picco3e347262005-09-03 15:54:28 -070094# SPARSEMEM_EXTREME (which is the default) does some bootmem
Matt LaPlante84eb8d02006-10-03 22:53:09 +020095# allocations when memory_present() is called. If this cannot
Bob Picco3e347262005-09-03 15:54:28 -070096# 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
Jan Beulich9ba16082008-10-15 22:01:38 -0700104 bool
Bob Picco3e347262005-09-03 15:54:28 -0700105
106#
Matt LaPlante44c09202006-10-03 22:34:14 +0200107# Architecture platforms which require a two level mem_section in SPARSEMEM
Bob Picco802f1922005-09-03 15:54:26 -0700108# must select this option. This is usually for architecture platforms with
109# an extremely sparse physical address space.
110#
Bob Picco3e347262005-09-03 15:54:28 -0700111config SPARSEMEM_EXTREME
112 def_bool y
113 depends on SPARSEMEM && !SPARSEMEM_STATIC
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700114
Andy Whitcroft29c71112007-10-16 01:24:14 -0700115config SPARSEMEM_VMEMMAP_ENABLE
Jan Beulich9ba16082008-10-15 22:01:38 -0700116 bool
Andy Whitcroft29c71112007-10-16 01:24:14 -0700117
Yinghai Lu9bdac912010-02-10 01:20:22 -0800118config SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
119 def_bool y
120 depends on SPARSEMEM && X86_64
121
Andy Whitcroft29c71112007-10-16 01:24:14 -0700122config SPARSEMEM_VMEMMAP
Geoff Levanda5ee6da2007-12-17 16:19:53 -0800123 bool "Sparse Memory virtual memmap"
124 depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
125 default y
126 help
127 SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
128 pfn_to_page and page_to_pfn operations. This is the most
129 efficient option when sufficient kernel resources are available.
Andy Whitcroft29c71112007-10-16 01:24:14 -0700130
Dave Hansen3947be12005-10-29 18:16:54 -0700131# eventually, we can have this option just 'select SPARSEMEM'
132config MEMORY_HOTPLUG
133 bool "Allow for memory hot-add"
Keith Manntheyec69acb2006-09-30 23:27:05 -0700134 depends on SPARSEMEM || X86_64_ACPI_NUMA
Andi Kleen6ad696d2009-11-17 14:06:22 -0800135 depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
Kumar Galaed84a072009-10-16 07:21:36 +0000136 depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
Dave Hansen3947be12005-10-29 18:16:54 -0700137
Keith Manntheyec69acb2006-09-30 23:27:05 -0700138config MEMORY_HOTPLUG_SPARSE
139 def_bool y
140 depends on SPARSEMEM && MEMORY_HOTPLUG
141
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700142config MEMORY_HOTREMOVE
143 bool "Allow for memory hot remove"
144 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
145 depends on MIGRATION
146
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700147#
148# If we have space for more page flags then we can enable additional
149# optimizations and functionality.
150#
151# Regular Sparsemem takes page flag bits for the sectionid if it does not
152# use a virtual memmap. Disable extended page flags for 32 bit platforms
153# that require the use of a sectionid in the page flags.
154#
155config PAGEFLAGS_EXTENDED
156 def_bool y
H. Peter Anvina269cca2009-08-31 11:17:44 -0700157 depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700158
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700159# Heavily threaded applications may benefit from splitting the mm-wide
160# page_table_lock, so that faults on different parts of the user address
161# space can be handled with less contention: split it at this NR_CPUS.
162# Default to 4 for wider testing, though 8 might be more appropriate.
163# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
Hugh Dickins7b6ac9d2005-11-23 13:37:37 -0800164# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800165# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700166#
167config SPLIT_PTLOCK_CPUS
168 int
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800169 default "999999" if ARM && !CPU_CACHE_VIPT
170 default "999999" if PARISC && !PA20
171 default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700172 default "4"
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800173
174#
175# support for page migration
176#
177config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800178 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700179 def_bool y
Gerald Schaefer83d16742008-07-23 21:28:22 -0700180 depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
Christoph Lameterb20a3502006-03-22 00:09:12 -0800181 help
182 Allows the migration of the physical location of pages of processes
183 while the virtual addresses are not changed. This is useful for
184 example on NUMA systems to put pages nearer to the processors accessing
185 the page.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700186
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700187config PHYS_ADDR_T_64BIT
188 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
189
Christoph Lameter4b51d662007-02-10 01:43:10 -0800190config ZONE_DMA_FLAG
191 int
192 default "0" if !ZONE_DMA
193 default "1"
194
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700195config BOUNCE
196 def_bool y
197 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
198
Christoph Lameter6225e932007-05-06 14:49:50 -0700199config NR_QUICK
200 int
201 depends on QUICKLIST
Haavard Skinnemoen38510752008-01-14 23:35:32 +0100202 default "2" if SUPERH || AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700203 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700204
205config VIRT_TO_BUS
206 def_bool y
207 depends on !ARCH_NO_VIRT_TO_BUS
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700208
209config MMU_NOTIFIER
210 bool
David Howellsfc4d5c22009-05-06 16:03:05 -0700211
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700212config KSM
213 bool "Enable KSM for page merging"
214 depends on MMU
215 help
216 Enable Kernel Samepage Merging: KSM periodically scans those areas
217 of an application's address space that an app has advised may be
218 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800219 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700220 saving memory until one or another app needs to modify the content.
221 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700222 See Documentation/vm/ksm.txt for more information: KSM is inactive
223 until a program has madvised that an area is MADV_MERGEABLE, and
224 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700225
Christoph Lametere0a94c22009-06-03 16:04:31 -0400226config DEFAULT_MMAP_MIN_ADDR
227 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000228 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400229 default 4096
230 help
231 This is the portion of low virtual memory which should be protected
232 from userspace allocation. Keeping a user from writing to low pages
233 can help reduce the impact of kernel NULL pointer bugs.
234
235 For most ia64, ppc64 and x86 users with lots of address space
236 a value of 65536 is reasonable and should cause no problems.
237 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400238 Programs which use vm86 functionality or have some need to map
239 this low address space will need CAP_SYS_RAWIO or disable this
240 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400241
242 This value can be changed after boot using the
243 /proc/sys/vm/mmap_min_addr tunable.
244
Linus Torvaldsd949f362009-09-26 09:35:07 -0700245config ARCH_SUPPORTS_MEMORY_FAILURE
246 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400247
Andi Kleen6a460792009-09-16 11:50:15 +0200248config MEMORY_FAILURE
249 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700250 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200251 bool "Enable recovery from hardware memory errors"
252 help
253 Enables code to recover from some memory failures on systems
254 with MCA recovery. This allows a system to continue running
255 even when some of its memory has uncorrected errors. This requires
256 special hardware support and typically ECC memory.
257
Andi Kleencae681f2009-09-16 11:50:17 +0200258config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100259 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100260 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100261 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200262
David Howellsfc4d5c22009-05-06 16:03:05 -0700263config NOMMU_INITIAL_TRIM_EXCESS
264 int "Turn on mmap() excess space trimming before booting"
265 depends on !MMU
266 default 1
267 help
268 The NOMMU mmap() frequently needs to allocate large contiguous chunks
269 of memory on which to store mappings, but it can only ask the system
270 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
271 more than it requires. To deal with this, mmap() is able to trim off
272 the excess and return it to the allocator.
273
274 If trimming is enabled, the excess is trimmed off and returned to the
275 system allocator, which can cause extra fragmentation, particularly
276 if there are a lot of transient processes.
277
278 If trimming is disabled, the excess is kept, but not used, which for
279 long-term mappings means that the space is wasted.
280
281 Trimming can be dynamically controlled through a sysctl option
282 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
283 excess pages there must be before trimming should occur, or zero if
284 no trimming is to occur.
285
286 This option specifies the initial value of this option. The default
287 of 1 says that all excess pages should be trimmed.
288
289 See Documentation/nommu-mmap.txt for more information.