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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
156 depends on X86_64
157 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
Dave Hansen3947be12005-10-29 18:16:54 -0700190
Keith Manntheyec69acb2006-09-30 23:27:05 -0700191config MEMORY_HOTPLUG_SPARSE
192 def_bool y
193 depends on SPARSEMEM && MEMORY_HOTPLUG
194
Vitaly Kuznetsov8604d9e2016-05-19 17:13:03 -0700195config MEMORY_HOTPLUG_DEFAULT_ONLINE
196 bool "Online the newly added memory blocks by default"
197 default n
198 depends on MEMORY_HOTPLUG
199 help
200 This option sets the default policy setting for memory hotplug
201 onlining policy (/sys/devices/system/memory/auto_online_blocks) which
202 determines what happens to newly added memory regions. Policy setting
203 can always be changed at runtime.
204 See Documentation/memory-hotplug.txt for more information.
205
206 Say Y here if you want all hot-plugged memory blocks to appear in
207 'online' state by default.
208 Say N here if you want the default policy to keep all hot-plugged
209 memory blocks in 'offline' state.
210
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700211config MEMORY_HOTREMOVE
212 bool "Allow for memory hot remove"
Yasuaki Ishimatsu46723bf2013-02-22 16:33:00 -0800213 select MEMORY_ISOLATION
Nathan Fontenotf7e33342013-09-27 10:18:09 -0500214 select HAVE_BOOTMEM_INFO_NODE if (X86_64 || PPC64)
KAMEZAWA Hiroyuki0c0e6192007-10-16 01:26:12 -0700215 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
216 depends on MIGRATION
217
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700218# Heavily threaded applications may benefit from splitting the mm-wide
219# page_table_lock, so that faults on different parts of the user address
220# space can be handled with less contention: split it at this NR_CPUS.
221# Default to 4 for wider testing, though 8 might be more appropriate.
222# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
Hugh Dickins7b6ac9d2005-11-23 13:37:37 -0800223# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800224# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700225#
226config SPLIT_PTLOCK_CPUS
227 int
Kirill A. Shutemov91645502014-04-07 15:37:14 -0700228 default "999999" if !MMU
Hugh Dickinsa70caa82009-12-14 17:59:02 -0800229 default "999999" if ARM && !CPU_CACHE_VIPT
230 default "999999" if PARISC && !PA20
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700231 default "4"
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800232
Kirill A. Shutemove009bb32013-11-14 14:31:07 -0800233config ARCH_ENABLE_SPLIT_PMD_PTLOCK
Christoph Jaeger6341e622014-12-20 15:41:11 -0500234 bool
Kirill A. Shutemove009bb32013-11-14 14:31:07 -0800235
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800236#
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700237# support for memory balloon
238config MEMORY_BALLOON
Christoph Jaeger6341e622014-12-20 15:41:11 -0500239 bool
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700240
241#
Rafael Aquini18468d92012-12-11 16:02:38 -0800242# support for memory balloon compaction
243config BALLOON_COMPACTION
244 bool "Allow for balloon memory compaction/migration"
245 def_bool y
Konstantin Khlebnikov09316c02014-10-09 15:29:32 -0700246 depends on COMPACTION && MEMORY_BALLOON
Rafael Aquini18468d92012-12-11 16:02:38 -0800247 help
248 Memory fragmentation introduced by ballooning might reduce
249 significantly the number of 2MB contiguous memory blocks that can be
250 used within a guest, thus imposing performance penalties associated
251 with the reduced number of transparent huge pages that could be used
252 by the guest workload. Allowing the compaction & migration for memory
253 pages enlisted as being part of memory balloon devices avoids the
254 scenario aforementioned and helps improving memory defragmentation.
255
256#
Mel Gormane9e96b32010-05-24 14:32:21 -0700257# support for memory compaction
258config COMPACTION
259 bool "Allow for memory compaction"
Rik van Riel05106e62012-10-08 16:33:03 -0700260 def_bool y
Mel Gormane9e96b32010-05-24 14:32:21 -0700261 select MIGRATION
Andrea Arcangeli33a93872011-01-25 15:07:25 -0800262 depends on MMU
Mel Gormane9e96b32010-05-24 14:32:21 -0700263 help
264 Allows the compaction of memory for the allocation of huge pages.
265
266#
Christoph Lameter7cbe34c2006-01-08 01:00:49 -0800267# support for page migration
268#
269config MIGRATION
Christoph Lameterb20a3502006-03-22 00:09:12 -0800270 bool "Page migration"
Christoph Lameter6c5240a2006-06-23 02:03:37 -0700271 def_bool y
Chen Gangde32a812013-09-12 15:14:08 -0700272 depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
Christoph Lameterb20a3502006-03-22 00:09:12 -0800273 help
274 Allows the migration of the physical location of pages of processes
Mel Gormane9e96b32010-05-24 14:32:21 -0700275 while the virtual addresses are not changed. This is useful in
276 two situations. The first is on NUMA systems to put pages nearer
277 to the processors accessing. The second is when allocating huge
278 pages as migration can relocate pages to satisfy a huge page
279 allocation instead of reclaiming.
Greg Kroah-Hartman6550e072006-06-12 17:11:31 -0700280
Naoya Horiguchic177c812014-06-04 16:05:35 -0700281config ARCH_ENABLE_HUGEPAGE_MIGRATION
Christoph Jaeger6341e622014-12-20 15:41:11 -0500282 bool
Naoya Horiguchic177c812014-06-04 16:05:35 -0700283
Jeremy Fitzhardinge600715d2008-09-11 01:31:45 -0700284config PHYS_ADDR_T_64BIT
285 def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
286
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700287config BOUNCE
Vinayak Menon9ca24e22013-04-29 15:08:55 -0700288 bool "Enable bounce buffers"
289 default y
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700290 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
Vinayak Menon9ca24e22013-04-29 15:08:55 -0700291 help
292 Enable bounce buffers for devices that cannot access
293 the full range of memory available to the CPU. Enabled
294 by default when ZONE_DMA or HIGHMEM is selected, but you
295 may say n to override this.
Christoph Lameter2a7326b2007-07-17 04:03:37 -0700296
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800297# On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often
298# have more than 4GB of memory, but we don't currently use the IOTLB to present
299# a 32-bit address to OHCI. So we need to use a bounce pool instead.
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800300config NEED_BOUNCE_POOL
301 bool
Valentin Rothbergdebeb292015-07-23 13:18:06 +0200302 default y if TILE && USB_OHCI_HCD
Darrick J. Wongffecfd12013-02-21 16:42:55 -0800303
Christoph Lameter6225e932007-05-06 14:49:50 -0700304config NR_QUICK
305 int
306 depends on QUICKLIST
Paul Mundt0176bd32010-01-05 12:35:00 +0900307 default "2" if AVR32
Christoph Lameter6225e932007-05-06 14:49:50 -0700308 default "1"
Stephen Rothwellf057eac2007-07-15 23:40:05 -0700309
310config VIRT_TO_BUS
Stephen Rothwell4febd952013-03-07 15:48:16 +1100311 bool
312 help
313 An architecture should select this if it implements the
314 deprecated interface virt_to_bus(). All new architectures
315 should probably not select this.
316
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700317
318config MMU_NOTIFIER
319 bool
Pranith Kumar83fe27e2014-12-05 11:24:45 -0500320 select SRCU
David Howellsfc4d5c22009-05-06 16:03:05 -0700321
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700322config KSM
323 bool "Enable KSM for page merging"
324 depends on MMU
325 help
326 Enable Kernel Samepage Merging: KSM periodically scans those areas
327 of an application's address space that an app has advised may be
328 mergeable. When it finds pages of identical content, it replaces
Hugh Dickinsd0f209f2009-12-14 17:59:34 -0800329 the many instances by a single page with that content, so
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700330 saving memory until one or another app needs to modify the content.
331 Recommended for use with KVM, or with other duplicative applications.
Hugh Dickinsc73602a2009-10-07 16:32:22 -0700332 See Documentation/vm/ksm.txt for more information: KSM is inactive
333 until a program has madvised that an area is MADV_MERGEABLE, and
334 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
Hugh Dickinsf8af4da2009-09-21 17:01:57 -0700335
Christoph Lametere0a94c22009-06-03 16:04:31 -0400336config DEFAULT_MMAP_MIN_ADDR
337 int "Low address space to protect from user allocation"
David Howells6e141542009-12-15 19:27:45 +0000338 depends on MMU
Christoph Lametere0a94c22009-06-03 16:04:31 -0400339 default 4096
340 help
341 This is the portion of low virtual memory which should be protected
342 from userspace allocation. Keeping a user from writing to low pages
343 can help reduce the impact of kernel NULL pointer bugs.
344
345 For most ia64, ppc64 and x86 users with lots of address space
346 a value of 65536 is reasonable and should cause no problems.
347 On arm and other archs it should not be higher than 32768.
Eric Paris788084a2009-07-31 12:54:11 -0400348 Programs which use vm86 functionality or have some need to map
349 this low address space will need CAP_SYS_RAWIO or disable this
350 protection by setting the value to 0.
Christoph Lametere0a94c22009-06-03 16:04:31 -0400351
352 This value can be changed after boot using the
353 /proc/sys/vm/mmap_min_addr tunable.
354
Linus Torvaldsd949f362009-09-26 09:35:07 -0700355config ARCH_SUPPORTS_MEMORY_FAILURE
356 bool
Christoph Lametere0a94c22009-06-03 16:04:31 -0400357
Andi Kleen6a460792009-09-16 11:50:15 +0200358config MEMORY_FAILURE
359 depends on MMU
Linus Torvaldsd949f362009-09-26 09:35:07 -0700360 depends on ARCH_SUPPORTS_MEMORY_FAILURE
Andi Kleen6a460792009-09-16 11:50:15 +0200361 bool "Enable recovery from hardware memory errors"
Minchan Kimee6f5092012-07-31 16:43:50 -0700362 select MEMORY_ISOLATION
Xie XiuQi97f0b132015-06-24 16:57:36 -0700363 select RAS
Andi Kleen6a460792009-09-16 11:50:15 +0200364 help
365 Enables code to recover from some memory failures on systems
366 with MCA recovery. This allows a system to continue running
367 even when some of its memory has uncorrected errors. This requires
368 special hardware support and typically ECC memory.
369
Andi Kleencae681f2009-09-16 11:50:17 +0200370config HWPOISON_INJECT
Andi Kleen413f9ef2009-12-16 12:20:00 +0100371 tristate "HWPoison pages injector"
Andi Kleen27df5062009-12-21 19:56:42 +0100372 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
Wu Fengguang478c5ff2009-12-16 12:19:59 +0100373 select PROC_PAGE_MONITOR
Andi Kleencae681f2009-09-16 11:50:17 +0200374
David Howellsfc4d5c22009-05-06 16:03:05 -0700375config NOMMU_INITIAL_TRIM_EXCESS
376 int "Turn on mmap() excess space trimming before booting"
377 depends on !MMU
378 default 1
379 help
380 The NOMMU mmap() frequently needs to allocate large contiguous chunks
381 of memory on which to store mappings, but it can only ask the system
382 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
383 more than it requires. To deal with this, mmap() is able to trim off
384 the excess and return it to the allocator.
385
386 If trimming is enabled, the excess is trimmed off and returned to the
387 system allocator, which can cause extra fragmentation, particularly
388 if there are a lot of transient processes.
389
390 If trimming is disabled, the excess is kept, but not used, which for
391 long-term mappings means that the space is wasted.
392
393 Trimming can be dynamically controlled through a sysctl option
394 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
395 excess pages there must be before trimming should occur, or zero if
396 no trimming is to occur.
397
398 This option specifies the initial value of this option. The default
399 of 1 says that all excess pages should be trimmed.
400
401 See Documentation/nommu-mmap.txt for more information.
Tejun Heobbddff02010-09-03 18:22:48 +0200402
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800403config TRANSPARENT_HUGEPAGE
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800404 bool "Transparent Hugepage Support"
Gerald Schaefer15626062012-10-08 16:30:04 -0700405 depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
Andrea Arcangeli5d689242011-01-13 15:47:07 -0800406 select COMPACTION
Andrea Arcangeli4c76d9d2011-01-13 15:46:39 -0800407 help
408 Transparent Hugepages allows the kernel to use huge pages and
409 huge tlb transparently to the applications whenever possible.
410 This feature can improve computing performance to certain
411 applications by speeding up page faults during memory
412 allocation, by reducing the number of tlb misses and by speeding
413 up the pagetable walking.
414
415 If memory constrained on embedded, you may want to say N.
416
Andrea Arcangeli13ece882011-01-13 15:47:07 -0800417choice
418 prompt "Transparent Hugepage Support sysfs defaults"
419 depends on TRANSPARENT_HUGEPAGE
420 default TRANSPARENT_HUGEPAGE_ALWAYS
421 help
422 Selects the sysfs defaults for Transparent Hugepage Support.
423
424 config TRANSPARENT_HUGEPAGE_ALWAYS
425 bool "always"
426 help
427 Enabling Transparent Hugepage always, can increase the
428 memory footprint of applications without a guaranteed
429 benefit but it will work automatically for all applications.
430
431 config TRANSPARENT_HUGEPAGE_MADVISE
432 bool "madvise"
433 help
434 Enabling Transparent Hugepage madvise, will only provide a
435 performance improvement benefit to the applications using
436 madvise(MADV_HUGEPAGE) but it won't risk to increase the
437 memory footprint of applications without a guaranteed
438 benefit.
439endchoice
440
Tejun Heobbddff02010-09-03 18:22:48 +0200441#
442# UP and nommu archs use km based percpu allocator
443#
444config NEED_PER_CPU_KM
445 depends on !SMP
446 bool
447 default y
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600448
449config CLEANCACHE
450 bool "Enable cleancache driver to cache clean pages if tmem is present"
451 default n
452 help
453 Cleancache can be thought of as a page-granularity victim cache
454 for clean pages that the kernel's pageframe replacement algorithm
455 (PFRA) would like to keep around, but can't since there isn't enough
456 memory. So when the PFRA "evicts" a page, it first attempts to use
Michael Witten140a1ef2011-06-10 03:57:26 +0000457 cleancache code to put the data contained in that page into
Dan Magenheimer077b1f82011-05-26 10:01:36 -0600458 "transcendent memory", memory that is not directly accessible or
459 addressable by the kernel and is of unknown and possibly
460 time-varying size. And when a cleancache-enabled
461 filesystem wishes to access a page in a file on disk, it first
462 checks cleancache to see if it already contains it; if it does,
463 the page is copied into the kernel and a disk access is avoided.
464 When a transcendent memory driver is available (such as zcache or
465 Xen transcendent memory), a significant I/O reduction
466 may be achieved. When none is available, all cleancache calls
467 are reduced to a single pointer-compare-against-NULL resulting
468 in a negligible performance hit.
469
470 If unsure, say Y to enable cleancache
Dan Magenheimer27c6aec2012-04-09 17:10:34 -0600471
472config FRONTSWAP
473 bool "Enable frontswap to cache swap pages if tmem is present"
474 depends on SWAP
475 default n
476 help
477 Frontswap is so named because it can be thought of as the opposite
478 of a "backing" store for a swap device. The data is stored into
479 "transcendent memory", memory that is not directly accessible or
480 addressable by the kernel and is of unknown and possibly
481 time-varying size. When space in transcendent memory is available,
482 a significant swap I/O reduction may be achieved. When none is
483 available, all frontswap calls are reduced to a single pointer-
484 compare-against-NULL resulting in a negligible performance hit
485 and swap data is stored as normal on the matching swap device.
486
487 If unsure, say Y to enable frontswap.
Aneesh Kumar K.Vf825c732013-07-02 11:15:15 +0530488
489config CMA
490 bool "Contiguous Memory Allocator"
Chen Gangde32a812013-09-12 15:14:08 -0700491 depends on HAVE_MEMBLOCK && MMU
Aneesh Kumar K.Vf825c732013-07-02 11:15:15 +0530492 select MIGRATION
493 select MEMORY_ISOLATION
494 help
495 This enables the Contiguous Memory Allocator which allows other
496 subsystems to allocate big physically-contiguous blocks of memory.
497 CMA reserves a region of memory and allows only movable pages to
498 be allocated from it. This way, the kernel can use the memory for
499 pagecache and when a subsystem requests for contiguous area, the
500 allocated pages are migrated away to serve the contiguous request.
501
502 If unsure, say "n".
503
504config CMA_DEBUG
505 bool "CMA debug messages (DEVELOPMENT)"
506 depends on DEBUG_KERNEL && CMA
507 help
508 Turns on debug messages in CMA. This produces KERN_DEBUG
509 messages for every CMA call as well as various messages while
510 processing calls such as dma_alloc_from_contiguous().
511 This option does not affect warning and error messages.
Alexander Grafbf550fc2013-08-29 00:41:59 +0200512
Sasha Levin28b24c12015-04-14 15:44:57 -0700513config CMA_DEBUGFS
514 bool "CMA debugfs interface"
515 depends on CMA && DEBUG_FS
516 help
517 Turns on the DebugFS interface for CMA.
518
Joonsoo Kima2541292014-08-06 16:05:25 -0700519config CMA_AREAS
520 int "Maximum count of the CMA areas"
521 depends on CMA
522 default 7
523 help
524 CMA allows to create CMA areas for particular purpose, mainly,
525 used as device private area. This parameter sets the maximum
526 number of CMA area in the system.
527
528 If unsure, leave the default value "7".
529
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700530config MEM_SOFT_DIRTY
531 bool "Track memory changes"
532 depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
533 select PROC_PAGE_MONITOR
Seth Jennings4e2e2772013-07-10 16:04:55 -0700534 help
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700535 This option enables memory changes tracking by introducing a
536 soft-dirty bit on pte-s. This bit it set when someone writes
537 into a page just as regular dirty bit, but unlike the latter
538 it can be cleared by hands.
539
540 See Documentation/vm/soft-dirty.txt for more details.
Seth Jennings4e2e2772013-07-10 16:04:55 -0700541
Seth Jennings2b281112013-07-10 16:05:03 -0700542config ZSWAP
543 bool "Compressed cache for swap pages (EXPERIMENTAL)"
544 depends on FRONTSWAP && CRYPTO=y
545 select CRYPTO_LZO
Dan Streetman12d79d62014-08-06 16:08:40 -0700546 select ZPOOL
Seth Jennings2b281112013-07-10 16:05:03 -0700547 default n
548 help
549 A lightweight compressed cache for swap pages. It takes
550 pages that are in the process of being swapped out and attempts to
551 compress them into a dynamically allocated RAM-based memory pool.
552 This can result in a significant I/O reduction on swap device and,
553 in the case where decompressing from RAM is faster that swap device
554 reads, can also improve workload performance.
555
556 This is marked experimental because it is a new feature (as of
557 v3.11) that interacts heavily with memory reclaim. While these
558 interactions don't cause any known issues on simple memory setups,
559 they have not be fully explored on the large set of potential
560 configurations and workloads that exist.
561
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700562config ZPOOL
563 tristate "Common API for compressed memory storage"
564 default n
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700565 help
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700566 Compressed memory storage API. This allows using either zbud or
567 zsmalloc.
Pavel Emelyanov0f8975e2013-07-03 15:01:20 -0700568
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700569config ZBUD
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700570 tristate "Low (Up to 2x) density storage for compressed pages"
Dan Streetmanaf8d4172014-08-06 16:08:36 -0700571 default n
572 help
573 A special purpose allocator for storing compressed pages.
574 It is designed to store up to two compressed pages per physical
575 page. While this design limits storage density, it has simple and
576 deterministic reclaim properties that make it preferable to a higher
577 density approach when reclaim will be used.
Minchan Kimbcf16472014-01-30 15:45:50 -0800578
Vitaly Wool9a001fc2016-05-20 16:58:30 -0700579config Z3FOLD
580 tristate "Up to 3x density storage for compressed pages"
581 depends on ZPOOL
582 default n
583 help
584 A special purpose allocator for storing compressed pages.
585 It is designed to store up to three compressed pages per physical
586 page. It is a ZBUD derivative so the simplicity and determinism are
587 still there.
588
Minchan Kimbcf16472014-01-30 15:45:50 -0800589config ZSMALLOC
Minchan Kimd867f202014-06-04 16:11:10 -0700590 tristate "Memory allocator for compressed pages"
Minchan Kimbcf16472014-01-30 15:45:50 -0800591 depends on MMU
592 default n
593 help
594 zsmalloc is a slab-based memory allocator designed to store
595 compressed RAM pages. zsmalloc uses virtual memory mapping
596 in order to reduce fragmentation. However, this results in a
597 non-standard allocator interface where a handle, not a pointer, is
598 returned by an alloc(). This handle must be mapped in order to
599 access the allocated space.
600
601config PGTABLE_MAPPING
602 bool "Use page table mapping to access object in zsmalloc"
603 depends on ZSMALLOC
604 help
605 By default, zsmalloc uses a copy-based object mapping method to
606 access allocations that span two pages. However, if a particular
607 architecture (ex, ARM) performs VM mapping faster than copying,
608 then you should select this. This causes zsmalloc to use page table
609 mapping rather than copying for object mapping.
610
Ben Hutchings2216ee82014-03-10 15:49:46 -0700611 You can check speed with zsmalloc benchmark:
612 https://github.com/spartacus06/zsmapbench
Mark Salter9e5c33d2014-04-07 15:39:48 -0700613
Ganesh Mahendran0f050d92015-02-12 15:00:54 -0800614config ZSMALLOC_STAT
615 bool "Export zsmalloc statistics"
616 depends on ZSMALLOC
617 select DEBUG_FS
618 help
619 This option enables code in the zsmalloc to collect various
620 statistics about whats happening in zsmalloc and exports that
621 information to userspace via debugfs.
622 If unsure, say N.
623
Mark Salter9e5c33d2014-04-07 15:39:48 -0700624config GENERIC_EARLY_IOREMAP
625 bool
Helge Deller042d27a2014-04-30 23:26:02 +0200626
627config MAX_STACK_SIZE_MB
628 int "Maximum user stack size for 32-bit processes (MB)"
629 default 80
630 range 8 256 if METAG
631 range 8 2048
632 depends on STACK_GROWSUP && (!64BIT || COMPAT)
633 help
634 This is the maximum stack size in Megabytes in the VM layout of 32-bit
635 user processes when the stack grows upwards (currently only on parisc
636 and metag arch). The stack will be located at the highest memory
637 address minus the given value, unless the RLIMIT_STACK hard limit is
638 changed to a smaller value in which case that is used.
639
640 A sane initial value is 80 MB.
Mel Gorman3a80a7f2015-06-30 14:57:02 -0700641
642# For architectures that support deferred memory initialisation
643config ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
644 bool
645
646config DEFERRED_STRUCT_PAGE_INIT
Vlastimil Babka1ce22102016-02-05 15:36:21 -0800647 bool "Defer initialisation of struct pages to kthreads"
Mel Gorman3a80a7f2015-06-30 14:57:02 -0700648 default n
649 depends on ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
650 depends on MEMORY_HOTPLUG
651 help
652 Ordinarily all struct pages are initialised during early boot in a
653 single thread. On very large machines this can take a considerable
654 amount of time. If this option is set, large machines will bring up
655 a subset of memmap at boot and then initialise the rest in parallel
Vlastimil Babka1ce22102016-02-05 15:36:21 -0800656 by starting one-off "pgdatinitX" kernel thread for each node X. This
657 has a potential performance impact on processes running early in the
658 lifetime of the system until these kthreads finish the
659 initialisation.
Dan Williams033fbae2015-08-09 15:29:06 -0400660
Vladimir Davydov33c3fc72015-09-09 15:35:45 -0700661config IDLE_PAGE_TRACKING
662 bool "Enable idle page tracking"
663 depends on SYSFS && MMU
664 select PAGE_EXTENSION if !64BIT
665 help
666 This feature allows to estimate the amount of user pages that have
667 not been touched during a given period of time. This information can
668 be useful to tune memory cgroup limits and/or for job placement
669 within a compute cluster.
670
671 See Documentation/vm/idle_page_tracking.txt for more details.
672
Dan Williams033fbae2015-08-09 15:29:06 -0400673config ZONE_DEVICE
674 bool "Device memory (pmem, etc...) hotplug support" if EXPERT
Dan Williams033fbae2015-08-09 15:29:06 -0400675 depends on MEMORY_HOTPLUG
676 depends on MEMORY_HOTREMOVE
Dan Williams99490f12016-03-17 14:19:58 -0700677 depends on SPARSEMEM_VMEMMAP
Dan Williams033fbae2015-08-09 15:29:06 -0400678 depends on X86_64 #arch_add_memory() comprehends device memory
679
680 help
681 Device memory hotplug support allows for establishing pmem,
682 or other device driver discovered memory regions, in the
683 memmap. This allows pfn_to_page() lookups of otherwise
684 "device-physical" addresses which is needed for using a DAX
685 mapping in an O_DIRECT operation, among other things.
686
687 If FS_DAX is enabled, then say Y.
Linus Torvalds06a660a2015-09-11 16:42:39 -0700688
Jan Kara8025e5d2015-07-13 11:55:44 -0300689config FRAME_VECTOR
690 bool
Dave Hansen63c17fb2016-02-12 13:02:08 -0800691
692config ARCH_USES_HIGH_VMA_FLAGS
693 bool
Dave Hansen66d37572016-02-12 13:02:32 -0800694config ARCH_HAS_PKEYS
695 bool