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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#
Mel Gormane9e96b32010-05-24 14:32:21 -0700175# support for memory compaction
176config COMPACTION
177 bool "Allow for memory compaction"
178 select MIGRATION
179 depends on EXPERIMENTAL && HUGETLB_PAGE && MMU
180 help
181 Allows the compaction of memory for the allocation of huge pages.
182
183#
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800184# support for page migration
185#
186config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800187 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700188 def_bool y
Gerald Schaefer83d16742008-07-23 21:28:22 -0700189 depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
Christoph Lameterb20a3502006-03-22 00:09:12 -0800190 help
191 Allows the migration of the physical location of pages of processes
Mel Gormane9e96b32010-05-24 14:32:21 -0700192 while the virtual addresses are not changed. This is useful in
193 two situations. The first is on NUMA systems to put pages nearer
194 to the processors accessing. The second is when allocating huge
195 pages as migration can relocate pages to satisfy a huge page
196 allocation instead of reclaiming.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700197
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700198config PHYS_ADDR_T_64BIT
199 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
200
Christoph Lameter4b51d662007-02-10 01:43:10 -0800201config ZONE_DMA_FLAG
202 int
203 default "0" if !ZONE_DMA
204 default "1"
205
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700206config BOUNCE
207 def_bool y
208 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
209
Christoph Lameter6225e932007-05-06 14:49:50 -0700210config NR_QUICK
211 int
212 depends on QUICKLIST
Paul Mundt0176bd32010-01-05 12:35:00 +0900213 default "2" if AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700214 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700215
216config VIRT_TO_BUS
217 def_bool y
218 depends on !ARCH_NO_VIRT_TO_BUS
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700219
220config MMU_NOTIFIER
221 bool
David Howellsfc4d5c22009-05-06 16:03:05 -0700222
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700223config KSM
224 bool "Enable KSM for page merging"
225 depends on MMU
226 help
227 Enable Kernel Samepage Merging: KSM periodically scans those areas
228 of an application's address space that an app has advised may be
229 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800230 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700231 saving memory until one or another app needs to modify the content.
232 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700233 See Documentation/vm/ksm.txt for more information: KSM is inactive
234 until a program has madvised that an area is MADV_MERGEABLE, and
235 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700236
Christoph Lametere0a94c22009-06-03 16:04:31 -0400237config DEFAULT_MMAP_MIN_ADDR
238 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000239 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400240 default 4096
241 help
242 This is the portion of low virtual memory which should be protected
243 from userspace allocation. Keeping a user from writing to low pages
244 can help reduce the impact of kernel NULL pointer bugs.
245
246 For most ia64, ppc64 and x86 users with lots of address space
247 a value of 65536 is reasonable and should cause no problems.
248 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400249 Programs which use vm86 functionality or have some need to map
250 this low address space will need CAP_SYS_RAWIO or disable this
251 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400252
253 This value can be changed after boot using the
254 /proc/sys/vm/mmap_min_addr tunable.
255
Linus Torvaldsd949f362009-09-26 09:35:07 -0700256config ARCH_SUPPORTS_MEMORY_FAILURE
257 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400258
Andi Kleen6a460792009-09-16 11:50:15 +0200259config MEMORY_FAILURE
260 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700261 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200262 bool "Enable recovery from hardware memory errors"
263 help
264 Enables code to recover from some memory failures on systems
265 with MCA recovery. This allows a system to continue running
266 even when some of its memory has uncorrected errors. This requires
267 special hardware support and typically ECC memory.
268
Andi Kleencae681f2009-09-16 11:50:17 +0200269config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100270 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100271 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100272 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200273
David Howellsfc4d5c22009-05-06 16:03:05 -0700274config NOMMU_INITIAL_TRIM_EXCESS
275 int "Turn on mmap() excess space trimming before booting"
276 depends on !MMU
277 default 1
278 help
279 The NOMMU mmap() frequently needs to allocate large contiguous chunks
280 of memory on which to store mappings, but it can only ask the system
281 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
282 more than it requires. To deal with this, mmap() is able to trim off
283 the excess and return it to the allocator.
284
285 If trimming is enabled, the excess is trimmed off and returned to the
286 system allocator, which can cause extra fragmentation, particularly
287 if there are a lot of transient processes.
288
289 If trimming is disabled, the excess is kept, but not used, which for
290 long-term mappings means that the space is wasted.
291
292 Trimming can be dynamically controlled through a sysctl option
293 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
294 excess pages there must be before trimming should occur, or zero if
295 no trimming is to occur.
296
297 This option specifies the initial value of this option. The default
298 of 1 says that all excess pages should be trimmed.
299
300 See Documentation/nommu-mmap.txt for more information.