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Dave Hansene1785e82005-06-23 00:07:49 -07001config SELECT_MEMORY_MODEL
2 def_bool y
Kees Cooka8826ee2013-01-16 18:54:17 -08003 depends on ARCH_SELECT_MEMORY_MODEL
Dave Hansene1785e82005-06-23 00:07:49 -07004
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.
Geert Uytterhoeven18f65332013-09-15 12:01:33 +020023 DISCONTIGMEM is a more mature, better tested system,
Andy Whitcroftd41dee32005-06-23 00:07:54 -070024 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
Christoph Jaeger6341e622014-12-20 15:41:11 -0500132 bool
Yinghai Lu95f72d12010-07-12 14:36:09 +1000133
Tejun Heo7c0caeb2011-07-14 11:43:42 +0200134config HAVE_MEMBLOCK_NODE_MAP
Christoph Jaeger6341e622014-12-20 15:41:11 -0500135 bool
Tejun Heo7c0caeb2011-07-14 11:43:42 +0200136
Philipp Hachtmann70210ed2014-01-29 18:16:01 +0100137config HAVE_MEMBLOCK_PHYS_MAP
Christoph Jaeger6341e622014-12-20 15:41:11 -0500138 bool
Philipp Hachtmann70210ed2014-01-29 18:16:01 +0100139
Steve Capper2667f502014-10-09 15:29:14 -0700140config HAVE_GENERIC_RCU_GUP
Christoph Jaeger6341e622014-12-20 15:41:11 -0500141 bool
Steve Capper2667f502014-10-09 15:29:14 -0700142
Tejun Heoc378ddd2011-07-14 11:46:03 +0200143config ARCH_DISCARD_MEMBLOCK
Christoph Jaeger6341e622014-12-20 15:41:11 -0500144 bool
Tejun Heoc378ddd2011-07-14 11:46:03 +0200145
Sam Ravnborg66616722011-10-31 17:08:20 -0700146config NO_BOOTMEM
Christoph Jaeger6341e622014-12-20 15:41:11 -0500147 bool
Sam Ravnborg66616722011-10-31 17:08:20 -0700148
Minchan Kimee6f5092012-07-31 16:43:50 -0700149config MEMORY_ISOLATION
Christoph Jaeger6341e622014-12-20 15:41:11 -0500150 bool
Minchan Kimee6f5092012-07-31 16:43:50 -0700151
Lai Jiangshan20b2f522012-12-12 13:52:00 -0800152config MOVABLE_NODE
Christoph Jaeger6341e622014-12-20 15:41:11 -0500153 bool "Enable to assign a node which has only movable memory"
Lai Jiangshan20b2f522012-12-12 13:52:00 -0800154 depends on HAVE_MEMBLOCK
155 depends on NO_BOOTMEM
Reza Arbab41a9ada2016-12-12 16:43:02 -0800156 depends on X86_64 || OF_EARLY_FLATTREE || MEMORY_HOTPLUG
Lai Jiangshan20b2f522012-12-12 13:52:00 -0800157 depends on NUMA
Tang Chenc2974052012-12-18 14:21:33 -0800158 default n
159 help
160 Allow a node to have only movable memory. Pages used by the kernel,
161 such as direct mapping pages cannot be migrated. So the corresponding
Tang Chenc5320922013-11-12 15:08:10 -0800162 memory device cannot be hotplugged. This option allows the following
163 two things:
164 - When the system is booting, node full of hotpluggable memory can
165 be arranged to have only movable memory so that the whole node can
166 be hot-removed. (need movable_node boot option specified).
167 - After the system is up, the option allows users to online all the
168 memory of a node as movable memory so that the whole node can be
169 hot-removed.
170
171 Users who don't use the memory hotplug feature are fine with this
172 option on since they don't specify movable_node boot option or they
173 don't online memory as movable.
Tang Chenc2974052012-12-18 14:21:33 -0800174
175 Say Y here if you want to hotplug a whole node.
176 Say N here if you want kernel to use memory on all nodes evenly.
Lai Jiangshan20b2f522012-12-12 13:52:00 -0800177
Yasuaki Ishimatsu46723bf2013-02-22 16:33:00 -0800178#
179# Only be set on architectures that have completely implemented memory hotplug
180# feature. If you are not sure, don't touch it.
181#
182config HAVE_BOOTMEM_INFO_NODE
183 def_bool n
184
Dave Hansen3947be12005-10-29 18:16:54 -0700185# eventually, we can have this option just 'select SPARSEMEM'
186config MEMORY_HOTPLUG
187 bool "Allow for memory hot-add"
Keith Manntheyec69acb2006-09-30 23:27:05 -0700188 depends on SPARSEMEM || X86_64_ACPI_NUMA
Stephen Rothwell40b31362013-05-21 13:49:35 +1000189 depends on ARCH_ENABLE_MEMORY_HOTPLUG
Linus Torvalds67463e52016-10-27 16:23:01 -0700190 depends on COMPILE_TEST || !KASAN
Dave Hansen3947be12005-10-29 18:16:54 -0700191
Keith Manntheyec69acb2006-09-30 23:27:05 -0700192config MEMORY_HOTPLUG_SPARSE
193 def_bool y
194 depends on SPARSEMEM && MEMORY_HOTPLUG
195
Vitaly Kuznetsov8604d9e2016-05-19 17:13:03 -0700196config MEMORY_HOTPLUG_DEFAULT_ONLINE
197 bool "Online the newly added memory blocks by default"
198 default n
199 depends on MEMORY_HOTPLUG
200 help
201 This option sets the default policy setting for memory hotplug
202 onlining policy (/sys/devices/system/memory/auto_online_blocks) which
203 determines what happens to newly added memory regions. Policy setting
204 can always be changed at runtime.
205 See Documentation/memory-hotplug.txt for more information.
206
207 Say Y here if you want all hot-plugged memory blocks to appear in
208 'online' state by default.
209 Say N here if you want the default policy to keep all hot-plugged
210 memory blocks in 'offline' state.
211
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700212config MEMORY_HOTREMOVE
213 bool "Allow for memory hot remove"
Yasuaki Ishimatsu46723bf2013-02-22 16:33:00 -0800214 select MEMORY_ISOLATION
Nathan Fontenotf7e33342013-09-27 10:18:09 -0500215 select HAVE_BOOTMEM_INFO_NODE if (X86_64 || PPC64)
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700216 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
217 depends on MIGRATION
218
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700219# Heavily threaded applications may benefit from splitting the mm-wide
220# page_table_lock, so that faults on different parts of the user address
221# space can be handled with less contention: split it at this NR_CPUS.
222# Default to 4 for wider testing, though 8 might be more appropriate.
223# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
Hugh Dickins7b6ac9d2005-11-23 13:37:37 -0800224# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800225# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700226#
227config SPLIT_PTLOCK_CPUS
228 int
Kirill A. Shutemov91645502014-04-07 15:37:14 -0700229 default "999999" if !MMU
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800230 default "999999" if ARM && !CPU_CACHE_VIPT
231 default "999999" if PARISC && !PA20
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700232 default "4"
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800233
Kirill A. Shutemove009bb32013-11-14 14:31:07 -0800234config ARCH_ENABLE_SPLIT_PMD_PTLOCK
Christoph Jaeger6341e622014-12-20 15:41:11 -0500235 bool
Kirill A. Shutemove009bb32013-11-14 14:31:07 -0800236
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800237#
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700238# support for memory balloon
239config MEMORY_BALLOON
Christoph Jaeger6341e622014-12-20 15:41:11 -0500240 bool
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700241
242#
Rafael Aquini18468d92012-12-11 16:02:38 -0800243# support for memory balloon compaction
244config BALLOON_COMPACTION
245 bool "Allow for balloon memory compaction/migration"
246 def_bool y
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700247 depends on COMPACTION && MEMORY_BALLOON
Rafael Aquini18468d92012-12-11 16:02:38 -0800248 help
249 Memory fragmentation introduced by ballooning might reduce
250 significantly the number of 2MB contiguous memory blocks that can be
251 used within a guest, thus imposing performance penalties associated
252 with the reduced number of transparent huge pages that could be used
253 by the guest workload. Allowing the compaction & migration for memory
254 pages enlisted as being part of memory balloon devices avoids the
255 scenario aforementioned and helps improving memory defragmentation.
256
257#
Mel Gormane9e96b32010-05-24 14:32:21 -0700258# support for memory compaction
259config COMPACTION
260 bool "Allow for memory compaction"
Rik van Riel05106e62012-10-08 16:33:03 -0700261 def_bool y
Mel Gormane9e96b32010-05-24 14:32:21 -0700262 select MIGRATION
Andrea Arcangeli33a93872011-01-25 15:07:25 -0800263 depends on MMU
Mel Gormane9e96b32010-05-24 14:32:21 -0700264 help
Michal Hockob32eaf72016-08-25 15:17:05 -0700265 Compaction is the only memory management component to form
266 high order (larger physically contiguous) memory blocks
267 reliably. The page allocator relies on compaction heavily and
268 the lack of the feature can lead to unexpected OOM killer
269 invocations for high order memory requests. You shouldn't
270 disable this option unless there really is a strong reason for
271 it and then we would be really interested to hear about that at
272 linux-mm@kvack.org.
Mel Gormane9e96b32010-05-24 14:32:21 -0700273
274#
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800275# support for page migration
276#
277config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800278 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700279 def_bool y
Chen Gangde32a812013-09-12 15:14:08 -0700280 depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
Christoph Lameterb20a3502006-03-22 00:09:12 -0800281 help
282 Allows the migration of the physical location of pages of processes
Mel Gormane9e96b32010-05-24 14:32:21 -0700283 while the virtual addresses are not changed. This is useful in
284 two situations. The first is on NUMA systems to put pages nearer
285 to the processors accessing. The second is when allocating huge
286 pages as migration can relocate pages to satisfy a huge page
287 allocation instead of reclaiming.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700288
Naoya Horiguchic177c812014-06-04 16:05:35 -0700289config ARCH_ENABLE_HUGEPAGE_MIGRATION
Christoph Jaeger6341e622014-12-20 15:41:11 -0500290 bool
Naoya Horiguchic177c812014-06-04 16:05:35 -0700291
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700292config PHYS_ADDR_T_64BIT
293 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
294
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700295config BOUNCE
Vinayak Menon9ca24e22013-04-29 15:08:55 -0700296 bool "Enable bounce buffers"
297 default y
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700298 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
Vinayak Menon9ca24e22013-04-29 15:08:55 -0700299 help
300 Enable bounce buffers for devices that cannot access
301 the full range of memory available to the CPU. Enabled
302 by default when ZONE_DMA or HIGHMEM is selected, but you
303 may say n to override this.
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700304
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800305# On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often
306# have more than 4GB of memory, but we don't currently use the IOTLB to present
307# a 32-bit address to OHCI. So we need to use a bounce pool instead.
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800308config NEED_BOUNCE_POOL
309 bool
Valentin Rothbergdebeb292015-07-23 13:18:06 +0200310 default y if TILE && USB_OHCI_HCD
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800311
Christoph Lameter6225e932007-05-06 14:49:50 -0700312config NR_QUICK
313 int
314 depends on QUICKLIST
Paul Mundt0176bd32010-01-05 12:35:00 +0900315 default "2" if AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700316 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700317
318config VIRT_TO_BUS
Stephen Rothwell4febd952013-03-07 15:48:16 +1100319 bool
320 help
321 An architecture should select this if it implements the
322 deprecated interface virt_to_bus(). All new architectures
323 should probably not select this.
324
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700325
326config MMU_NOTIFIER
327 bool
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500328 select SRCU
David Howellsfc4d5c22009-05-06 16:03:05 -0700329
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700330config KSM
331 bool "Enable KSM for page merging"
332 depends on MMU
333 help
334 Enable Kernel Samepage Merging: KSM periodically scans those areas
335 of an application's address space that an app has advised may be
336 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800337 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700338 saving memory until one or another app needs to modify the content.
339 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700340 See Documentation/vm/ksm.txt for more information: KSM is inactive
341 until a program has madvised that an area is MADV_MERGEABLE, and
342 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700343
Christoph Lametere0a94c22009-06-03 16:04:31 -0400344config DEFAULT_MMAP_MIN_ADDR
345 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000346 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400347 default 4096
348 help
349 This is the portion of low virtual memory which should be protected
350 from userspace allocation. Keeping a user from writing to low pages
351 can help reduce the impact of kernel NULL pointer bugs.
352
353 For most ia64, ppc64 and x86 users with lots of address space
354 a value of 65536 is reasonable and should cause no problems.
355 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400356 Programs which use vm86 functionality or have some need to map
357 this low address space will need CAP_SYS_RAWIO or disable this
358 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400359
360 This value can be changed after boot using the
361 /proc/sys/vm/mmap_min_addr tunable.
362
Linus Torvaldsd949f362009-09-26 09:35:07 -0700363config ARCH_SUPPORTS_MEMORY_FAILURE
364 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400365
Andi Kleen6a460792009-09-16 11:50:15 +0200366config MEMORY_FAILURE
367 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700368 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200369 bool "Enable recovery from hardware memory errors"
Minchan Kimee6f5092012-07-31 16:43:50 -0700370 select MEMORY_ISOLATION
Xie XiuQi97f0b132015-06-24 16:57:36 -0700371 select RAS
Andi Kleen6a460792009-09-16 11:50:15 +0200372 help
373 Enables code to recover from some memory failures on systems
374 with MCA recovery. This allows a system to continue running
375 even when some of its memory has uncorrected errors. This requires
376 special hardware support and typically ECC memory.
377
Andi Kleencae681f2009-09-16 11:50:17 +0200378config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100379 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100380 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100381 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200382
David Howellsfc4d5c22009-05-06 16:03:05 -0700383config NOMMU_INITIAL_TRIM_EXCESS
384 int "Turn on mmap() excess space trimming before booting"
385 depends on !MMU
386 default 1
387 help
388 The NOMMU mmap() frequently needs to allocate large contiguous chunks
389 of memory on which to store mappings, but it can only ask the system
390 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
391 more than it requires. To deal with this, mmap() is able to trim off
392 the excess and return it to the allocator.
393
394 If trimming is enabled, the excess is trimmed off and returned to the
395 system allocator, which can cause extra fragmentation, particularly
396 if there are a lot of transient processes.
397
398 If trimming is disabled, the excess is kept, but not used, which for
399 long-term mappings means that the space is wasted.
400
401 Trimming can be dynamically controlled through a sysctl option
402 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
403 excess pages there must be before trimming should occur, or zero if
404 no trimming is to occur.
405
406 This option specifies the initial value of this option. The default
407 of 1 says that all excess pages should be trimmed.
408
409 See Documentation/nommu-mmap.txt for more information.
Tejun Heobbddff02010-09-03 18:22:48 +0200410
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800411config TRANSPARENT_HUGEPAGE
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800412 bool "Transparent Hugepage Support"
Gerald Schaefer15626062012-10-08 16:30:04 -0700413 depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
Andrea Arcangeli5d689242011-01-13 15:47:07 -0800414 select COMPACTION
Matthew Wilcox57578c22016-05-20 17:01:54 -0700415 select RADIX_TREE_MULTIORDER
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800416 help
417 Transparent Hugepages allows the kernel to use huge pages and
418 huge tlb transparently to the applications whenever possible.
419 This feature can improve computing performance to certain
420 applications by speeding up page faults during memory
421 allocation, by reducing the number of tlb misses and by speeding
422 up the pagetable walking.
423
424 If memory constrained on embedded, you may want to say N.
425
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800426choice
427 prompt "Transparent Hugepage Support sysfs defaults"
428 depends on TRANSPARENT_HUGEPAGE
429 default TRANSPARENT_HUGEPAGE_ALWAYS
430 help
431 Selects the sysfs defaults for Transparent Hugepage Support.
432
433 config TRANSPARENT_HUGEPAGE_ALWAYS
434 bool "always"
435 help
436 Enabling Transparent Hugepage always, can increase the
437 memory footprint of applications without a guaranteed
438 benefit but it will work automatically for all applications.
439
440 config TRANSPARENT_HUGEPAGE_MADVISE
441 bool "madvise"
442 help
443 Enabling Transparent Hugepage madvise, will only provide a
444 performance improvement benefit to the applications using
445 madvise(MADV_HUGEPAGE) but it won't risk to increase the
446 memory footprint of applications without a guaranteed
447 benefit.
448endchoice
449
Kirill A. Shutemove496cf32016-07-26 15:26:35 -0700450config TRANSPARENT_HUGE_PAGECACHE
451 def_bool y
Aneesh Kumar K.V953c66c2016-12-12 16:44:32 -0800452 depends on TRANSPARENT_HUGEPAGE
Kirill A. Shutemove496cf32016-07-26 15:26:35 -0700453
454#
Tejun Heobbddff02010-09-03 18:22:48 +0200455# UP and nommu archs use km based percpu allocator
456#
457config NEED_PER_CPU_KM
458 depends on !SMP
459 bool
460 default y
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600461
462config CLEANCACHE
463 bool "Enable cleancache driver to cache clean pages if tmem is present"
464 default n
465 help
466 Cleancache can be thought of as a page-granularity victim cache
467 for clean pages that the kernel's pageframe replacement algorithm
468 (PFRA) would like to keep around, but can't since there isn't enough
469 memory. So when the PFRA "evicts" a page, it first attempts to use
Michael Witten140a1ef2011-06-10 03:57:26 +0000470 cleancache code to put the data contained in that page into
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600471 "transcendent memory", memory that is not directly accessible or
472 addressable by the kernel and is of unknown and possibly
473 time-varying size. And when a cleancache-enabled
474 filesystem wishes to access a page in a file on disk, it first
475 checks cleancache to see if it already contains it; if it does,
476 the page is copied into the kernel and a disk access is avoided.
477 When a transcendent memory driver is available (such as zcache or
478 Xen transcendent memory), a significant I/O reduction
479 may be achieved. When none is available, all cleancache calls
480 are reduced to a single pointer-compare-against-NULL resulting
481 in a negligible performance hit.
482
483 If unsure, say Y to enable cleancache
Dan Magenheimer27c6aec2012-04-09 17:10:34 -0600484
485config FRONTSWAP
486 bool "Enable frontswap to cache swap pages if tmem is present"
487 depends on SWAP
488 default n
489 help
490 Frontswap is so named because it can be thought of as the opposite
491 of a "backing" store for a swap device. The data is stored into
492 "transcendent memory", memory that is not directly accessible or
493 addressable by the kernel and is of unknown and possibly
494 time-varying size. When space in transcendent memory is available,
495 a significant swap I/O reduction may be achieved. When none is
496 available, all frontswap calls are reduced to a single pointer-
497 compare-against-NULL resulting in a negligible performance hit
498 and swap data is stored as normal on the matching swap device.
499
500 If unsure, say Y to enable frontswap.
Aneesh Kumar K.Vf825c732013-07-02 11:15:15 +0530501
502config CMA
503 bool "Contiguous Memory Allocator"
Chen Gangde32a812013-09-12 15:14:08 -0700504 depends on HAVE_MEMBLOCK && MMU
Aneesh Kumar K.Vf825c732013-07-02 11:15:15 +0530505 select MIGRATION
506 select MEMORY_ISOLATION
507 help
508 This enables the Contiguous Memory Allocator which allows other
509 subsystems to allocate big physically-contiguous blocks of memory.
510 CMA reserves a region of memory and allows only movable pages to
511 be allocated from it. This way, the kernel can use the memory for
512 pagecache and when a subsystem requests for contiguous area, the
513 allocated pages are migrated away to serve the contiguous request.
514
515 If unsure, say "n".
516
517config CMA_DEBUG
518 bool "CMA debug messages (DEVELOPMENT)"
519 depends on DEBUG_KERNEL && CMA
520 help
521 Turns on debug messages in CMA. This produces KERN_DEBUG
522 messages for every CMA call as well as various messages while
523 processing calls such as dma_alloc_from_contiguous().
524 This option does not affect warning and error messages.
Alexander Grafbf550fc2013-08-29 00:41:59 +0200525
Sasha Levin28b24c12015-04-14 15:44:57 -0700526config CMA_DEBUGFS
527 bool "CMA debugfs interface"
528 depends on CMA && DEBUG_FS
529 help
530 Turns on the DebugFS interface for CMA.
531
Joonsoo Kima2541292014-08-06 16:05:25 -0700532config CMA_AREAS
533 int "Maximum count of the CMA areas"
534 depends on CMA
535 default 7
536 help
537 CMA allows to create CMA areas for particular purpose, mainly,
538 used as device private area. This parameter sets the maximum
539 number of CMA area in the system.
540
541 If unsure, leave the default value "7".
542
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700543config MEM_SOFT_DIRTY
544 bool "Track memory changes"
545 depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
546 select PROC_PAGE_MONITOR
Seth Jennings4e2e2772013-07-10 16:04:55 -0700547 help
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700548 This option enables memory changes tracking by introducing a
549 soft-dirty bit on pte-s. This bit it set when someone writes
550 into a page just as regular dirty bit, but unlike the latter
551 it can be cleared by hands.
552
553 See Documentation/vm/soft-dirty.txt for more details.
Seth Jennings4e2e2772013-07-10 16:04:55 -0700554
Seth Jennings2b281112013-07-10 16:05:03 -0700555config ZSWAP
556 bool "Compressed cache for swap pages (EXPERIMENTAL)"
557 depends on FRONTSWAP && CRYPTO=y
558 select CRYPTO_LZO
Dan Streetman12d79d62014-08-06 16:08:40 -0700559 select ZPOOL
Seth Jennings2b281112013-07-10 16:05:03 -0700560 default n
561 help
562 A lightweight compressed cache for swap pages. It takes
563 pages that are in the process of being swapped out and attempts to
564 compress them into a dynamically allocated RAM-based memory pool.
565 This can result in a significant I/O reduction on swap device and,
566 in the case where decompressing from RAM is faster that swap device
567 reads, can also improve workload performance.
568
569 This is marked experimental because it is a new feature (as of
570 v3.11) that interacts heavily with memory reclaim. While these
571 interactions don't cause any known issues on simple memory setups,
572 they have not be fully explored on the large set of potential
573 configurations and workloads that exist.
574
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700575config ZPOOL
576 tristate "Common API for compressed memory storage"
577 default n
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700578 help
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700579 Compressed memory storage API. This allows using either zbud or
580 zsmalloc.
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700581
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700582config ZBUD
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700583 tristate "Low (Up to 2x) density storage for compressed pages"
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700584 default n
585 help
586 A special purpose allocator for storing compressed pages.
587 It is designed to store up to two compressed pages per physical
588 page. While this design limits storage density, it has simple and
589 deterministic reclaim properties that make it preferable to a higher
590 density approach when reclaim will be used.
Minchan Kimbcf16472014-01-30 15:45:50 -0800591
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700592config Z3FOLD
593 tristate "Up to 3x density storage for compressed pages"
594 depends on ZPOOL
595 default n
596 help
597 A special purpose allocator for storing compressed pages.
598 It is designed to store up to three compressed pages per physical
599 page. It is a ZBUD derivative so the simplicity and determinism are
600 still there.
601
Minchan Kimbcf16472014-01-30 15:45:50 -0800602config ZSMALLOC
Minchan Kimd867f202014-06-04 16:11:10 -0700603 tristate "Memory allocator for compressed pages"
Minchan Kimbcf16472014-01-30 15:45:50 -0800604 depends on MMU
605 default n
606 help
607 zsmalloc is a slab-based memory allocator designed to store
608 compressed RAM pages. zsmalloc uses virtual memory mapping
609 in order to reduce fragmentation. However, this results in a
610 non-standard allocator interface where a handle, not a pointer, is
611 returned by an alloc(). This handle must be mapped in order to
612 access the allocated space.
613
614config PGTABLE_MAPPING
615 bool "Use page table mapping to access object in zsmalloc"
616 depends on ZSMALLOC
617 help
618 By default, zsmalloc uses a copy-based object mapping method to
619 access allocations that span two pages. However, if a particular
620 architecture (ex, ARM) performs VM mapping faster than copying,
621 then you should select this. This causes zsmalloc to use page table
622 mapping rather than copying for object mapping.
623
Ben Hutchings2216ee82014-03-10 15:49:46 -0700624 You can check speed with zsmalloc benchmark:
625 https://github.com/spartacus06/zsmapbench
Mark Salter9e5c33d2014-04-07 15:39:48 -0700626
Ganesh Mahendran0f050d92015-02-12 15:00:54 -0800627config ZSMALLOC_STAT
628 bool "Export zsmalloc statistics"
629 depends on ZSMALLOC
630 select DEBUG_FS
631 help
632 This option enables code in the zsmalloc to collect various
633 statistics about whats happening in zsmalloc and exports that
634 information to userspace via debugfs.
635 If unsure, say N.
636
Mark Salter9e5c33d2014-04-07 15:39:48 -0700637config GENERIC_EARLY_IOREMAP
638 bool
Helge Deller042d27a2014-04-30 23:26:02 +0200639
640config MAX_STACK_SIZE_MB
641 int "Maximum user stack size for 32-bit processes (MB)"
642 default 80
643 range 8 256 if METAG
644 range 8 2048
645 depends on STACK_GROWSUP && (!64BIT || COMPAT)
646 help
647 This is the maximum stack size in Megabytes in the VM layout of 32-bit
648 user processes when the stack grows upwards (currently only on parisc
649 and metag arch). The stack will be located at the highest memory
650 address minus the given value, unless the RLIMIT_STACK hard limit is
651 changed to a smaller value in which case that is used.
652
653 A sane initial value is 80 MB.
Mel Gorman3a80a7f2015-06-30 14:57:02 -0700654
655# For architectures that support deferred memory initialisation
656config ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
657 bool
658
659config DEFERRED_STRUCT_PAGE_INIT
Vlastimil Babka1ce22102016-02-05 15:36:21 -0800660 bool "Defer initialisation of struct pages to kthreads"
Mel Gorman3a80a7f2015-06-30 14:57:02 -0700661 default n
662 depends on ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
Gavin Shan11e68562016-05-27 14:27:49 -0700663 depends on NO_BOOTMEM && MEMORY_HOTPLUG
Yang Shi95794922016-05-26 15:16:08 -0700664 depends on !FLATMEM
Mel Gorman3a80a7f2015-06-30 14:57:02 -0700665 help
666 Ordinarily all struct pages are initialised during early boot in a
667 single thread. On very large machines this can take a considerable
668 amount of time. If this option is set, large machines will bring up
669 a subset of memmap at boot and then initialise the rest in parallel
Vlastimil Babka1ce22102016-02-05 15:36:21 -0800670 by starting one-off "pgdatinitX" kernel thread for each node X. This
671 has a potential performance impact on processes running early in the
672 lifetime of the system until these kthreads finish the
673 initialisation.
Dan Williams033fbae2015-08-09 15:29:06 -0400674
Vladimir Davydov33c3fc72015-09-09 15:35:45 -0700675config IDLE_PAGE_TRACKING
676 bool "Enable idle page tracking"
677 depends on SYSFS && MMU
678 select PAGE_EXTENSION if !64BIT
679 help
680 This feature allows to estimate the amount of user pages that have
681 not been touched during a given period of time. This information can
682 be useful to tune memory cgroup limits and/or for job placement
683 within a compute cluster.
684
685 See Documentation/vm/idle_page_tracking.txt for more details.
686
Dan Williams033fbae2015-08-09 15:29:06 -0400687config ZONE_DEVICE
Dan Williamsc02b6ae2016-07-28 15:48:08 -0700688 bool "Device memory (pmem, etc...) hotplug support"
Dan Williams033fbae2015-08-09 15:29:06 -0400689 depends on MEMORY_HOTPLUG
690 depends on MEMORY_HOTREMOVE
Dan Williams99490f12016-03-17 14:19:58 -0700691 depends on SPARSEMEM_VMEMMAP
Dan Williams033fbae2015-08-09 15:29:06 -0400692 depends on X86_64 #arch_add_memory() comprehends device memory
693
694 help
695 Device memory hotplug support allows for establishing pmem,
696 or other device driver discovered memory regions, in the
697 memmap. This allows pfn_to_page() lookups of otherwise
698 "device-physical" addresses which is needed for using a DAX
699 mapping in an O_DIRECT operation, among other things.
700
701 If FS_DAX is enabled, then say Y.
Linus Torvalds06a660a2015-09-11 16:42:39 -0700702
Jan Kara8025e5d2015-07-13 11:55:44 -0300703config FRAME_VECTOR
704 bool
Dave Hansen63c17fb2016-02-12 13:02:08 -0800705
706config ARCH_USES_HIGH_VMA_FLAGS
707 bool
Dave Hansen66d37572016-02-12 13:02:32 -0800708config ARCH_HAS_PKEYS
709 bool