Commit | Line | Data |
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e1785e85 DH |
1 | config SELECT_MEMORY_MODEL |
2 | def_bool y | |
3 | depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL | |
4 | ||
3a9da765 DH |
5 | choice |
6 | prompt "Memory model" | |
e1785e85 DH |
7 | depends on SELECT_MEMORY_MODEL |
8 | default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT | |
d41dee36 | 9 | default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT |
e1785e85 | 10 | default FLATMEM_MANUAL |
3a9da765 | 11 | |
e1785e85 | 12 | config FLATMEM_MANUAL |
3a9da765 | 13 | bool "Flat Memory" |
c898ec16 | 14 | depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE |
3a9da765 DH |
15 | 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 | ||
d41dee36 AW |
21 | 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. | |
3a9da765 | 30 | |
e1785e85 | 31 | config DISCONTIGMEM_MANUAL |
f3519f91 | 32 | bool "Discontiguous Memory" |
3a9da765 DH |
33 | depends on ARCH_DISCONTIGMEM_ENABLE |
34 | help | |
785dcd44 DH |
35 | 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 | |
ad3d0a38 | 40 | can have degraded performance from the extra overhead that |
785dcd44 DH |
41 | this option imposes. |
42 | ||
43 | Many NUMA configurations will have this as the only option. | |
44 | ||
3a9da765 DH |
45 | If unsure, choose "Flat Memory" over this option. |
46 | ||
d41dee36 AW |
47 | config 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 | |
f3519f91 | 55 | "Discontiguous Memory". This option provides some potential |
d41dee36 AW |
56 | 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 | ||
3a9da765 DH |
62 | endchoice |
63 | ||
e1785e85 DH |
64 | config DISCONTIGMEM |
65 | def_bool y | |
66 | depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL | |
67 | ||
d41dee36 AW |
68 | config SPARSEMEM |
69 | def_bool y | |
1a83e175 | 70 | depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL |
d41dee36 | 71 | |
e1785e85 DH |
72 | config FLATMEM |
73 | def_bool y | |
d41dee36 AW |
74 | depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL |
75 | ||
76 | config FLAT_NODE_MEM_MAP | |
77 | def_bool y | |
78 | depends on !SPARSEMEM | |
e1785e85 | 79 | |
93b7504e DH |
80 | # |
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 | # | |
85 | config NEED_MULTIPLE_NODES | |
86 | def_bool y | |
87 | depends on DISCONTIGMEM || NUMA | |
af705362 AW |
88 | |
89 | config HAVE_MEMORY_PRESENT | |
90 | def_bool y | |
d41dee36 | 91 | depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM |
802f192e | 92 | |
3e347261 BP |
93 | # |
94 | # SPARSEMEM_EXTREME (which is the default) does some bootmem | |
84eb8d06 | 95 | # allocations when memory_present() is called. If this cannot |
3e347261 BP |
96 | # 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 | # | |
103 | config SPARSEMEM_STATIC | |
9ba16087 | 104 | bool |
3e347261 | 105 | |
802f192e | 106 | # |
44c09201 | 107 | # Architecture platforms which require a two level mem_section in SPARSEMEM |
802f192e BP |
108 | # must select this option. This is usually for architecture platforms with |
109 | # an extremely sparse physical address space. | |
110 | # | |
3e347261 BP |
111 | config SPARSEMEM_EXTREME |
112 | def_bool y | |
113 | depends on SPARSEMEM && !SPARSEMEM_STATIC | |
4c21e2f2 | 114 | |
29c71111 | 115 | config SPARSEMEM_VMEMMAP_ENABLE |
9ba16087 | 116 | bool |
29c71111 | 117 | |
9bdac914 YL |
118 | config SPARSEMEM_ALLOC_MEM_MAP_TOGETHER |
119 | def_bool y | |
120 | depends on SPARSEMEM && X86_64 | |
121 | ||
29c71111 | 122 | config SPARSEMEM_VMEMMAP |
a5ee6daa GL |
123 | 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. | |
29c71111 | 130 | |
3947be19 DH |
131 | # eventually, we can have this option just 'select SPARSEMEM' |
132 | config MEMORY_HOTPLUG | |
133 | bool "Allow for memory hot-add" | |
ec69acbb | 134 | depends on SPARSEMEM || X86_64_ACPI_NUMA |
6ad696d2 | 135 | depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG |
ed84a07a | 136 | depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390) |
3947be19 | 137 | |
ec69acbb KM |
138 | config MEMORY_HOTPLUG_SPARSE |
139 | def_bool y | |
140 | depends on SPARSEMEM && MEMORY_HOTPLUG | |
141 | ||
0c0e6195 KH |
142 | config MEMORY_HOTREMOVE |
143 | bool "Allow for memory hot remove" | |
144 | depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE | |
145 | depends on MIGRATION | |
146 | ||
e20b8cca CL |
147 | # |
148 | # If we have space for more page flags then we can enable additional | |
149 | # optimizations and functionality. | |
150 | # | |
151 | # Regular Sparsemem takes page flag bits for the sectionid if it does not | |
152 | # use a virtual memmap. Disable extended page flags for 32 bit platforms | |
153 | # that require the use of a sectionid in the page flags. | |
154 | # | |
155 | config PAGEFLAGS_EXTENDED | |
156 | def_bool y | |
a269cca9 | 157 | depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM |
e20b8cca | 158 | |
4c21e2f2 HD |
159 | # Heavily threaded applications may benefit from splitting the mm-wide |
160 | # page_table_lock, so that faults on different parts of the user address | |
161 | # space can be handled with less contention: split it at this NR_CPUS. | |
162 | # Default to 4 for wider testing, though 8 might be more appropriate. | |
163 | # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock. | |
7b6ac9df | 164 | # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes. |
a70caa8b | 165 | # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page. |
4c21e2f2 HD |
166 | # |
167 | config SPLIT_PTLOCK_CPUS | |
168 | int | |
a70caa8b HD |
169 | default "999999" if ARM && !CPU_CACHE_VIPT |
170 | default "999999" if PARISC && !PA20 | |
171 | default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC | |
4c21e2f2 | 172 | default "4" |
7cbe34cf CL |
173 | |
174 | # | |
175 | # support for page migration | |
176 | # | |
177 | config MIGRATION | |
b20a3503 | 178 | bool "Page migration" |
6c5240ae | 179 | def_bool y |
83d1674a | 180 | depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE |
b20a3503 CL |
181 | help |
182 | Allows the migration of the physical location of pages of processes | |
183 | while the virtual addresses are not changed. This is useful for | |
184 | example on NUMA systems to put pages nearer to the processors accessing | |
185 | the page. | |
6550e07f | 186 | |
600715dc JF |
187 | config PHYS_ADDR_T_64BIT |
188 | def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT | |
189 | ||
4b51d669 CL |
190 | config ZONE_DMA_FLAG |
191 | int | |
192 | default "0" if !ZONE_DMA | |
193 | default "1" | |
194 | ||
2a7326b5 CL |
195 | config BOUNCE |
196 | def_bool y | |
197 | depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM) | |
198 | ||
6225e937 CL |
199 | config NR_QUICK |
200 | int | |
201 | depends on QUICKLIST | |
0176bd3d | 202 | default "2" if AVR32 |
6225e937 | 203 | default "1" |
f057eac0 SR |
204 | |
205 | config VIRT_TO_BUS | |
206 | def_bool y | |
207 | depends on !ARCH_NO_VIRT_TO_BUS | |
cddb8a5c AA |
208 | |
209 | config MMU_NOTIFIER | |
210 | bool | |
fc4d5c29 | 211 | |
f8af4da3 HD |
212 | config KSM |
213 | bool "Enable KSM for page merging" | |
214 | depends on MMU | |
215 | help | |
216 | Enable Kernel Samepage Merging: KSM periodically scans those areas | |
217 | of an application's address space that an app has advised may be | |
218 | mergeable. When it finds pages of identical content, it replaces | |
d0f209f6 | 219 | the many instances by a single page with that content, so |
f8af4da3 HD |
220 | saving memory until one or another app needs to modify the content. |
221 | Recommended for use with KVM, or with other duplicative applications. | |
c73602ad HD |
222 | See Documentation/vm/ksm.txt for more information: KSM is inactive |
223 | until a program has madvised that an area is MADV_MERGEABLE, and | |
224 | root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set). | |
f8af4da3 | 225 | |
e0a94c2a CL |
226 | config DEFAULT_MMAP_MIN_ADDR |
227 | int "Low address space to protect from user allocation" | |
6e141546 | 228 | depends on MMU |
e0a94c2a CL |
229 | default 4096 |
230 | help | |
231 | This is the portion of low virtual memory which should be protected | |
232 | from userspace allocation. Keeping a user from writing to low pages | |
233 | can help reduce the impact of kernel NULL pointer bugs. | |
234 | ||
235 | For most ia64, ppc64 and x86 users with lots of address space | |
236 | a value of 65536 is reasonable and should cause no problems. | |
237 | On arm and other archs it should not be higher than 32768. | |
788084ab EP |
238 | Programs which use vm86 functionality or have some need to map |
239 | this low address space will need CAP_SYS_RAWIO or disable this | |
240 | protection by setting the value to 0. | |
e0a94c2a CL |
241 | |
242 | This value can be changed after boot using the | |
243 | /proc/sys/vm/mmap_min_addr tunable. | |
244 | ||
d949f36f LT |
245 | config ARCH_SUPPORTS_MEMORY_FAILURE |
246 | bool | |
e0a94c2a | 247 | |
6a46079c AK |
248 | config MEMORY_FAILURE |
249 | depends on MMU | |
d949f36f | 250 | depends on ARCH_SUPPORTS_MEMORY_FAILURE |
6a46079c AK |
251 | bool "Enable recovery from hardware memory errors" |
252 | help | |
253 | Enables code to recover from some memory failures on systems | |
254 | with MCA recovery. This allows a system to continue running | |
255 | even when some of its memory has uncorrected errors. This requires | |
256 | special hardware support and typically ECC memory. | |
257 | ||
cae681fc | 258 | config HWPOISON_INJECT |
413f9efb | 259 | tristate "HWPoison pages injector" |
27df5068 | 260 | depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS |
478c5ffc | 261 | select PROC_PAGE_MONITOR |
cae681fc | 262 | |
fc4d5c29 DH |
263 | config NOMMU_INITIAL_TRIM_EXCESS |
264 | int "Turn on mmap() excess space trimming before booting" | |
265 | depends on !MMU | |
266 | default 1 | |
267 | help | |
268 | The NOMMU mmap() frequently needs to allocate large contiguous chunks | |
269 | of memory on which to store mappings, but it can only ask the system | |
270 | allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently | |
271 | more than it requires. To deal with this, mmap() is able to trim off | |
272 | the excess and return it to the allocator. | |
273 | ||
274 | If trimming is enabled, the excess is trimmed off and returned to the | |
275 | system allocator, which can cause extra fragmentation, particularly | |
276 | if there are a lot of transient processes. | |
277 | ||
278 | If trimming is disabled, the excess is kept, but not used, which for | |
279 | long-term mappings means that the space is wasted. | |
280 | ||
281 | Trimming can be dynamically controlled through a sysctl option | |
282 | (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of | |
283 | excess pages there must be before trimming should occur, or zero if | |
284 | no trimming is to occur. | |
285 | ||
286 | This option specifies the initial value of this option. The default | |
287 | of 1 says that all excess pages should be trimmed. | |
288 | ||
289 | See Documentation/nommu-mmap.txt for more information. |