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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
Dave Hansen3947be12005-10-29 18:16:54 -0700134# eventually, we can have this option just 'select SPARSEMEM'
135config MEMORY_HOTPLUG
136 bool "Allow for memory hot-add"
Keith Manntheyec69acb2006-09-30 23:27:05 -0700137 depends on SPARSEMEM || X86_64_ACPI_NUMA
Andi Kleen6ad696d2009-11-17 14:06:22 -0800138 depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
Kumar Galaed84a072009-10-16 07:21:36 +0000139 depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
Dave Hansen3947be12005-10-29 18:16:54 -0700140
Keith Manntheyec69acb2006-09-30 23:27:05 -0700141config MEMORY_HOTPLUG_SPARSE
142 def_bool y
143 depends on SPARSEMEM && MEMORY_HOTPLUG
144
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700145config MEMORY_HOTREMOVE
146 bool "Allow for memory hot remove"
147 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
148 depends on MIGRATION
149
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700150#
151# If we have space for more page flags then we can enable additional
152# optimizations and functionality.
153#
154# Regular Sparsemem takes page flag bits for the sectionid if it does not
155# use a virtual memmap. Disable extended page flags for 32 bit platforms
156# that require the use of a sectionid in the page flags.
157#
158config PAGEFLAGS_EXTENDED
159 def_bool y
H. Peter Anvina269cca2009-08-31 11:17:44 -0700160 depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700161
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700162# Heavily threaded applications may benefit from splitting the mm-wide
163# page_table_lock, so that faults on different parts of the user address
164# space can be handled with less contention: split it at this NR_CPUS.
165# Default to 4 for wider testing, though 8 might be more appropriate.
166# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
Hugh Dickins7b6ac9d2005-11-23 13:37:37 -0800167# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800168# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700169#
170config SPLIT_PTLOCK_CPUS
171 int
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800172 default "999999" if ARM && !CPU_CACHE_VIPT
173 default "999999" if PARISC && !PA20
174 default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700175 default "4"
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800176
177#
Mel Gormane9e96b32010-05-24 14:32:21 -0700178# support for memory compaction
179config COMPACTION
180 bool "Allow for memory compaction"
181 select MIGRATION
Andrea Arcangeli33a93872011-01-25 15:07:25 -0800182 depends on MMU
Mel Gormane9e96b32010-05-24 14:32:21 -0700183 help
184 Allows the compaction of memory for the allocation of huge pages.
185
186#
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800187# support for page migration
188#
189config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800190 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700191 def_bool y
Andrea Arcangeli152e0652010-09-09 16:37:53 -0700192 depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800193 help
194 Allows the migration of the physical location of pages of processes
Mel Gormane9e96b32010-05-24 14:32:21 -0700195 while the virtual addresses are not changed. This is useful in
196 two situations. The first is on NUMA systems to put pages nearer
197 to the processors accessing. The second is when allocating huge
198 pages as migration can relocate pages to satisfy a huge page
199 allocation instead of reclaiming.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700200
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700201config PHYS_ADDR_T_64BIT
202 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
203
Christoph Lameter4b51d662007-02-10 01:43:10 -0800204config ZONE_DMA_FLAG
205 int
206 default "0" if !ZONE_DMA
207 default "1"
208
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700209config BOUNCE
210 def_bool y
211 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
212
Christoph Lameter6225e932007-05-06 14:49:50 -0700213config NR_QUICK
214 int
215 depends on QUICKLIST
Paul Mundt0176bd32010-01-05 12:35:00 +0900216 default "2" if AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700217 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700218
219config VIRT_TO_BUS
220 def_bool y
221 depends on !ARCH_NO_VIRT_TO_BUS
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700222
223config MMU_NOTIFIER
224 bool
David Howellsfc4d5c22009-05-06 16:03:05 -0700225
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700226config KSM
227 bool "Enable KSM for page merging"
228 depends on MMU
229 help
230 Enable Kernel Samepage Merging: KSM periodically scans those areas
231 of an application's address space that an app has advised may be
232 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800233 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700234 saving memory until one or another app needs to modify the content.
235 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700236 See Documentation/vm/ksm.txt for more information: KSM is inactive
237 until a program has madvised that an area is MADV_MERGEABLE, and
238 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700239
Christoph Lametere0a94c22009-06-03 16:04:31 -0400240config DEFAULT_MMAP_MIN_ADDR
241 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000242 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400243 default 4096
244 help
245 This is the portion of low virtual memory which should be protected
246 from userspace allocation. Keeping a user from writing to low pages
247 can help reduce the impact of kernel NULL pointer bugs.
248
249 For most ia64, ppc64 and x86 users with lots of address space
250 a value of 65536 is reasonable and should cause no problems.
251 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400252 Programs which use vm86 functionality or have some need to map
253 this low address space will need CAP_SYS_RAWIO or disable this
254 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400255
256 This value can be changed after boot using the
257 /proc/sys/vm/mmap_min_addr tunable.
258
Linus Torvaldsd949f362009-09-26 09:35:07 -0700259config ARCH_SUPPORTS_MEMORY_FAILURE
260 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400261
Andi Kleen6a460792009-09-16 11:50:15 +0200262config MEMORY_FAILURE
263 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700264 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200265 bool "Enable recovery from hardware memory errors"
266 help
267 Enables code to recover from some memory failures on systems
268 with MCA recovery. This allows a system to continue running
269 even when some of its memory has uncorrected errors. This requires
270 special hardware support and typically ECC memory.
271
Andi Kleencae681f2009-09-16 11:50:17 +0200272config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100273 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100274 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100275 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200276
David Howellsfc4d5c22009-05-06 16:03:05 -0700277config NOMMU_INITIAL_TRIM_EXCESS
278 int "Turn on mmap() excess space trimming before booting"
279 depends on !MMU
280 default 1
281 help
282 The NOMMU mmap() frequently needs to allocate large contiguous chunks
283 of memory on which to store mappings, but it can only ask the system
284 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
285 more than it requires. To deal with this, mmap() is able to trim off
286 the excess and return it to the allocator.
287
288 If trimming is enabled, the excess is trimmed off and returned to the
289 system allocator, which can cause extra fragmentation, particularly
290 if there are a lot of transient processes.
291
292 If trimming is disabled, the excess is kept, but not used, which for
293 long-term mappings means that the space is wasted.
294
295 Trimming can be dynamically controlled through a sysctl option
296 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
297 excess pages there must be before trimming should occur, or zero if
298 no trimming is to occur.
299
300 This option specifies the initial value of this option. The default
301 of 1 says that all excess pages should be trimmed.
302
303 See Documentation/nommu-mmap.txt for more information.
Tejun Heobbddff02010-09-03 18:22:48 +0200304
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800305config TRANSPARENT_HUGEPAGE
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800306 bool "Transparent Hugepage Support"
Johannes Weinerf2d6bfe2011-01-13 15:47:01 -0800307 depends on X86 && MMU
Andrea Arcangeli5d689242011-01-13 15:47:07 -0800308 select COMPACTION
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800309 help
310 Transparent Hugepages allows the kernel to use huge pages and
311 huge tlb transparently to the applications whenever possible.
312 This feature can improve computing performance to certain
313 applications by speeding up page faults during memory
314 allocation, by reducing the number of tlb misses and by speeding
315 up the pagetable walking.
316
317 If memory constrained on embedded, you may want to say N.
318
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800319choice
320 prompt "Transparent Hugepage Support sysfs defaults"
321 depends on TRANSPARENT_HUGEPAGE
322 default TRANSPARENT_HUGEPAGE_ALWAYS
323 help
324 Selects the sysfs defaults for Transparent Hugepage Support.
325
326 config TRANSPARENT_HUGEPAGE_ALWAYS
327 bool "always"
328 help
329 Enabling Transparent Hugepage always, can increase the
330 memory footprint of applications without a guaranteed
331 benefit but it will work automatically for all applications.
332
333 config TRANSPARENT_HUGEPAGE_MADVISE
334 bool "madvise"
335 help
336 Enabling Transparent Hugepage madvise, will only provide a
337 performance improvement benefit to the applications using
338 madvise(MADV_HUGEPAGE) but it won't risk to increase the
339 memory footprint of applications without a guaranteed
340 benefit.
341endchoice
342
Tejun Heobbddff02010-09-03 18:22:48 +0200343#
344# UP and nommu archs use km based percpu allocator
345#
346config NEED_PER_CPU_KM
347 depends on !SMP
348 bool
349 default y
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600350
351config CLEANCACHE
352 bool "Enable cleancache driver to cache clean pages if tmem is present"
353 default n
354 help
355 Cleancache can be thought of as a page-granularity victim cache
356 for clean pages that the kernel's pageframe replacement algorithm
357 (PFRA) would like to keep around, but can't since there isn't enough
358 memory. So when the PFRA "evicts" a page, it first attempts to use
359 cleancacne code to put the data contained in that page into
360 "transcendent memory", memory that is not directly accessible or
361 addressable by the kernel and is of unknown and possibly
362 time-varying size. And when a cleancache-enabled
363 filesystem wishes to access a page in a file on disk, it first
364 checks cleancache to see if it already contains it; if it does,
365 the page is copied into the kernel and a disk access is avoided.
366 When a transcendent memory driver is available (such as zcache or
367 Xen transcendent memory), a significant I/O reduction
368 may be achieved. When none is available, all cleancache calls
369 are reduced to a single pointer-compare-against-NULL resulting
370 in a negligible performance hit.
371
372 If unsure, say Y to enable cleancache