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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
Yinghai Lu95f72d12010-07-12 14:36:09 +1000131config HAVE_MEMBLOCK
132 boolean
133
Tejun Heo7c0caeb2011-07-14 11:43:42 +0200134config HAVE_MEMBLOCK_NODE_MAP
135 boolean
136
Dave Hansen3947be12005-10-29 18:16:54 -0700137# eventually, we can have this option just 'select SPARSEMEM'
138config MEMORY_HOTPLUG
139 bool "Allow for memory hot-add"
Keith Manntheyec69acb2006-09-30 23:27:05 -0700140 depends on SPARSEMEM || X86_64_ACPI_NUMA
Andi Kleen6ad696d2009-11-17 14:06:22 -0800141 depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
Kumar Galaed84a072009-10-16 07:21:36 +0000142 depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
Dave Hansen3947be12005-10-29 18:16:54 -0700143
Keith Manntheyec69acb2006-09-30 23:27:05 -0700144config MEMORY_HOTPLUG_SPARSE
145 def_bool y
146 depends on SPARSEMEM && MEMORY_HOTPLUG
147
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700148config MEMORY_HOTREMOVE
149 bool "Allow for memory hot remove"
150 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
151 depends on MIGRATION
152
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700153#
154# If we have space for more page flags then we can enable additional
155# optimizations and functionality.
156#
157# Regular Sparsemem takes page flag bits for the sectionid if it does not
158# use a virtual memmap. Disable extended page flags for 32 bit platforms
159# that require the use of a sectionid in the page flags.
160#
161config PAGEFLAGS_EXTENDED
162 def_bool y
H. Peter Anvina269cca2009-08-31 11:17:44 -0700163 depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700164
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700165# Heavily threaded applications may benefit from splitting the mm-wide
166# page_table_lock, so that faults on different parts of the user address
167# space can be handled with less contention: split it at this NR_CPUS.
168# Default to 4 for wider testing, though 8 might be more appropriate.
169# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
Hugh Dickins7b6ac9d2005-11-23 13:37:37 -0800170# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800171# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700172#
173config SPLIT_PTLOCK_CPUS
174 int
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800175 default "999999" if ARM && !CPU_CACHE_VIPT
176 default "999999" if PARISC && !PA20
177 default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700178 default "4"
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800179
180#
Mel Gormane9e96b32010-05-24 14:32:21 -0700181# support for memory compaction
182config COMPACTION
183 bool "Allow for memory compaction"
184 select MIGRATION
Andrea Arcangeli33a93872011-01-25 15:07:25 -0800185 depends on MMU
Mel Gormane9e96b32010-05-24 14:32:21 -0700186 help
187 Allows the compaction of memory for the allocation of huge pages.
188
189#
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800190# support for page migration
191#
192config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800193 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700194 def_bool y
Andrea Arcangeli152e0652010-09-09 16:37:53 -0700195 depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800196 help
197 Allows the migration of the physical location of pages of processes
Mel Gormane9e96b32010-05-24 14:32:21 -0700198 while the virtual addresses are not changed. This is useful in
199 two situations. The first is on NUMA systems to put pages nearer
200 to the processors accessing. The second is when allocating huge
201 pages as migration can relocate pages to satisfy a huge page
202 allocation instead of reclaiming.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700203
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700204config PHYS_ADDR_T_64BIT
205 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
206
Christoph Lameter4b51d662007-02-10 01:43:10 -0800207config ZONE_DMA_FLAG
208 int
209 default "0" if !ZONE_DMA
210 default "1"
211
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700212config BOUNCE
213 def_bool y
214 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
215
Christoph Lameter6225e932007-05-06 14:49:50 -0700216config NR_QUICK
217 int
218 depends on QUICKLIST
Paul Mundt0176bd32010-01-05 12:35:00 +0900219 default "2" if AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700220 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700221
222config VIRT_TO_BUS
223 def_bool y
224 depends on !ARCH_NO_VIRT_TO_BUS
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700225
226config MMU_NOTIFIER
227 bool
David Howellsfc4d5c22009-05-06 16:03:05 -0700228
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700229config KSM
230 bool "Enable KSM for page merging"
231 depends on MMU
232 help
233 Enable Kernel Samepage Merging: KSM periodically scans those areas
234 of an application's address space that an app has advised may be
235 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800236 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700237 saving memory until one or another app needs to modify the content.
238 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700239 See Documentation/vm/ksm.txt for more information: KSM is inactive
240 until a program has madvised that an area is MADV_MERGEABLE, and
241 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700242
Christoph Lametere0a94c22009-06-03 16:04:31 -0400243config DEFAULT_MMAP_MIN_ADDR
244 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000245 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400246 default 4096
247 help
248 This is the portion of low virtual memory which should be protected
249 from userspace allocation. Keeping a user from writing to low pages
250 can help reduce the impact of kernel NULL pointer bugs.
251
252 For most ia64, ppc64 and x86 users with lots of address space
253 a value of 65536 is reasonable and should cause no problems.
254 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400255 Programs which use vm86 functionality or have some need to map
256 this low address space will need CAP_SYS_RAWIO or disable this
257 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400258
259 This value can be changed after boot using the
260 /proc/sys/vm/mmap_min_addr tunable.
261
Linus Torvaldsd949f362009-09-26 09:35:07 -0700262config ARCH_SUPPORTS_MEMORY_FAILURE
263 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400264
Andi Kleen6a460792009-09-16 11:50:15 +0200265config MEMORY_FAILURE
266 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700267 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200268 bool "Enable recovery from hardware memory errors"
269 help
270 Enables code to recover from some memory failures on systems
271 with MCA recovery. This allows a system to continue running
272 even when some of its memory has uncorrected errors. This requires
273 special hardware support and typically ECC memory.
274
Andi Kleencae681f2009-09-16 11:50:17 +0200275config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100276 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100277 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100278 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200279
David Howellsfc4d5c22009-05-06 16:03:05 -0700280config NOMMU_INITIAL_TRIM_EXCESS
281 int "Turn on mmap() excess space trimming before booting"
282 depends on !MMU
283 default 1
284 help
285 The NOMMU mmap() frequently needs to allocate large contiguous chunks
286 of memory on which to store mappings, but it can only ask the system
287 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
288 more than it requires. To deal with this, mmap() is able to trim off
289 the excess and return it to the allocator.
290
291 If trimming is enabled, the excess is trimmed off and returned to the
292 system allocator, which can cause extra fragmentation, particularly
293 if there are a lot of transient processes.
294
295 If trimming is disabled, the excess is kept, but not used, which for
296 long-term mappings means that the space is wasted.
297
298 Trimming can be dynamically controlled through a sysctl option
299 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
300 excess pages there must be before trimming should occur, or zero if
301 no trimming is to occur.
302
303 This option specifies the initial value of this option. The default
304 of 1 says that all excess pages should be trimmed.
305
306 See Documentation/nommu-mmap.txt for more information.
Tejun Heobbddff02010-09-03 18:22:48 +0200307
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800308config TRANSPARENT_HUGEPAGE
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800309 bool "Transparent Hugepage Support"
Johannes Weinerf2d6bfe2011-01-13 15:47:01 -0800310 depends on X86 && MMU
Andrea Arcangeli5d689242011-01-13 15:47:07 -0800311 select COMPACTION
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800312 help
313 Transparent Hugepages allows the kernel to use huge pages and
314 huge tlb transparently to the applications whenever possible.
315 This feature can improve computing performance to certain
316 applications by speeding up page faults during memory
317 allocation, by reducing the number of tlb misses and by speeding
318 up the pagetable walking.
319
320 If memory constrained on embedded, you may want to say N.
321
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800322choice
323 prompt "Transparent Hugepage Support sysfs defaults"
324 depends on TRANSPARENT_HUGEPAGE
325 default TRANSPARENT_HUGEPAGE_ALWAYS
326 help
327 Selects the sysfs defaults for Transparent Hugepage Support.
328
329 config TRANSPARENT_HUGEPAGE_ALWAYS
330 bool "always"
331 help
332 Enabling Transparent Hugepage always, can increase the
333 memory footprint of applications without a guaranteed
334 benefit but it will work automatically for all applications.
335
336 config TRANSPARENT_HUGEPAGE_MADVISE
337 bool "madvise"
338 help
339 Enabling Transparent Hugepage madvise, will only provide a
340 performance improvement benefit to the applications using
341 madvise(MADV_HUGEPAGE) but it won't risk to increase the
342 memory footprint of applications without a guaranteed
343 benefit.
344endchoice
345
Tejun Heobbddff02010-09-03 18:22:48 +0200346#
347# UP and nommu archs use km based percpu allocator
348#
349config NEED_PER_CPU_KM
350 depends on !SMP
351 bool
352 default y
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600353
354config CLEANCACHE
355 bool "Enable cleancache driver to cache clean pages if tmem is present"
356 default n
357 help
358 Cleancache can be thought of as a page-granularity victim cache
359 for clean pages that the kernel's pageframe replacement algorithm
360 (PFRA) would like to keep around, but can't since there isn't enough
361 memory. So when the PFRA "evicts" a page, it first attempts to use
362 cleancacne code to put the data contained in that page into
363 "transcendent memory", memory that is not directly accessible or
364 addressable by the kernel and is of unknown and possibly
365 time-varying size. And when a cleancache-enabled
366 filesystem wishes to access a page in a file on disk, it first
367 checks cleancache to see if it already contains it; if it does,
368 the page is copied into the kernel and a disk access is avoided.
369 When a transcendent memory driver is available (such as zcache or
370 Xen transcendent memory), a significant I/O reduction
371 may be achieved. When none is available, all cleancache calls
372 are reduced to a single pointer-compare-against-NULL resulting
373 in a negligible performance hit.
374
375 If unsure, say Y to enable cleancache