1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 2
3 menu "Memory Management options" 3 menu "Memory Management options"
4 4
5 # 5 #
6 # For some reason microblaze and nios2 hard co 6 # For some reason microblaze and nios2 hard code SWAP=n. Hopefully we can
7 # add proper SWAP support to them, in which ca 7 # add proper SWAP support to them, in which case this can be remove.
8 # 8 #
9 config ARCH_NO_SWAP 9 config ARCH_NO_SWAP
10 bool 10 bool
11 11
12 config ZPOOL 12 config ZPOOL
13 bool 13 bool
14 14
15 menuconfig SWAP 15 menuconfig SWAP
16 bool "Support for paging of anonymous 16 bool "Support for paging of anonymous memory (swap)"
17 depends on MMU && BLOCK && !ARCH_NO_SW 17 depends on MMU && BLOCK && !ARCH_NO_SWAP
18 default y 18 default y
19 help 19 help
20 This option allows you to choose whe 20 This option allows you to choose whether you want to have support
21 for so called swap devices or swap f 21 for so called swap devices or swap files in your kernel that are
22 used to provide more virtual memory 22 used to provide more virtual memory than the actual RAM present
23 in your computer. If unsure say Y. 23 in your computer. If unsure say Y.
24 24
25 config ZSWAP 25 config ZSWAP
26 bool "Compressed cache for swap pages" !! 26 bool "Compressed cache for swap pages (EXPERIMENTAL)"
27 depends on SWAP 27 depends on SWAP
>> 28 select FRONTSWAP
28 select CRYPTO 29 select CRYPTO
29 select ZPOOL 30 select ZPOOL
30 help 31 help
31 A lightweight compressed cache for s 32 A lightweight compressed cache for swap pages. It takes
32 pages that are in the process of bei 33 pages that are in the process of being swapped out and attempts to
33 compress them into a dynamically all 34 compress them into a dynamically allocated RAM-based memory pool.
34 This can result in a significant I/O 35 This can result in a significant I/O reduction on swap device and,
35 in the case where decompressing from 36 in the case where decompressing from RAM is faster than swap device
36 reads, can also improve workload per 37 reads, can also improve workload performance.
37 38
>> 39 This is marked experimental because it is a new feature (as of
>> 40 v3.11) that interacts heavily with memory reclaim. While these
>> 41 interactions don't cause any known issues on simple memory setups,
>> 42 they have not be fully explored on the large set of potential
>> 43 configurations and workloads that exist.
>> 44
38 config ZSWAP_DEFAULT_ON 45 config ZSWAP_DEFAULT_ON
39 bool "Enable the compressed cache for 46 bool "Enable the compressed cache for swap pages by default"
40 depends on ZSWAP 47 depends on ZSWAP
41 help 48 help
42 If selected, the compressed cache fo 49 If selected, the compressed cache for swap pages will be enabled
43 at boot, otherwise it will be disabl 50 at boot, otherwise it will be disabled.
44 51
45 The selection made here can be overr 52 The selection made here can be overridden by using the kernel
46 command line 'zswap.enabled=' option 53 command line 'zswap.enabled=' option.
47 54
48 config ZSWAP_SHRINKER_DEFAULT_ON <<
49 bool "Shrink the zswap pool on memory <<
50 depends on ZSWAP <<
51 default n <<
52 help <<
53 If selected, the zswap shrinker will <<
54 stored in the zswap pool will become <<
55 written back to the backing swap dev <<
56 <<
57 This means that zswap writeback coul <<
58 not yet full, or the cgroup zswap li <<
59 reducing the chance that cold pages <<
60 and consume memory indefinitely. <<
61 <<
62 choice 55 choice
63 prompt "Default compressor" 56 prompt "Default compressor"
64 depends on ZSWAP 57 depends on ZSWAP
65 default ZSWAP_COMPRESSOR_DEFAULT_LZO 58 default ZSWAP_COMPRESSOR_DEFAULT_LZO
66 help 59 help
67 Selects the default compression algo 60 Selects the default compression algorithm for the compressed cache
68 for swap pages. 61 for swap pages.
69 62
70 For an overview what kind of perform 63 For an overview what kind of performance can be expected from
71 a particular compression algorithm p 64 a particular compression algorithm please refer to the benchmarks
72 available at the following LWN page: 65 available at the following LWN page:
73 https://lwn.net/Articles/751795/ 66 https://lwn.net/Articles/751795/
74 67
75 If in doubt, select 'LZO'. 68 If in doubt, select 'LZO'.
76 69
77 The selection made here can be overr 70 The selection made here can be overridden by using the kernel
78 command line 'zswap.compressor=' opt 71 command line 'zswap.compressor=' option.
79 72
80 config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE 73 config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
81 bool "Deflate" 74 bool "Deflate"
82 select CRYPTO_DEFLATE 75 select CRYPTO_DEFLATE
83 help 76 help
84 Use the Deflate algorithm as the def 77 Use the Deflate algorithm as the default compression algorithm.
85 78
86 config ZSWAP_COMPRESSOR_DEFAULT_LZO 79 config ZSWAP_COMPRESSOR_DEFAULT_LZO
87 bool "LZO" 80 bool "LZO"
88 select CRYPTO_LZO 81 select CRYPTO_LZO
89 help 82 help
90 Use the LZO algorithm as the default 83 Use the LZO algorithm as the default compression algorithm.
91 84
92 config ZSWAP_COMPRESSOR_DEFAULT_842 85 config ZSWAP_COMPRESSOR_DEFAULT_842
93 bool "842" 86 bool "842"
94 select CRYPTO_842 87 select CRYPTO_842
95 help 88 help
96 Use the 842 algorithm as the default 89 Use the 842 algorithm as the default compression algorithm.
97 90
98 config ZSWAP_COMPRESSOR_DEFAULT_LZ4 91 config ZSWAP_COMPRESSOR_DEFAULT_LZ4
99 bool "LZ4" 92 bool "LZ4"
100 select CRYPTO_LZ4 93 select CRYPTO_LZ4
101 help 94 help
102 Use the LZ4 algorithm as the default 95 Use the LZ4 algorithm as the default compression algorithm.
103 96
104 config ZSWAP_COMPRESSOR_DEFAULT_LZ4HC 97 config ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
105 bool "LZ4HC" 98 bool "LZ4HC"
106 select CRYPTO_LZ4HC 99 select CRYPTO_LZ4HC
107 help 100 help
108 Use the LZ4HC algorithm as the defau 101 Use the LZ4HC algorithm as the default compression algorithm.
109 102
110 config ZSWAP_COMPRESSOR_DEFAULT_ZSTD 103 config ZSWAP_COMPRESSOR_DEFAULT_ZSTD
111 bool "zstd" 104 bool "zstd"
112 select CRYPTO_ZSTD 105 select CRYPTO_ZSTD
113 help 106 help
114 Use the zstd algorithm as the defaul 107 Use the zstd algorithm as the default compression algorithm.
115 endchoice 108 endchoice
116 109
117 config ZSWAP_COMPRESSOR_DEFAULT 110 config ZSWAP_COMPRESSOR_DEFAULT
118 string 111 string
119 depends on ZSWAP 112 depends on ZSWAP
120 default "deflate" if ZSWAP_COMPRESSOR_D 113 default "deflate" if ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
121 default "lzo" if ZSWAP_COMPRESSOR_DEFAU 114 default "lzo" if ZSWAP_COMPRESSOR_DEFAULT_LZO
122 default "842" if ZSWAP_COMPRESSOR_DEFAU 115 default "842" if ZSWAP_COMPRESSOR_DEFAULT_842
123 default "lz4" if ZSWAP_COMPRESSOR_DEFAU 116 default "lz4" if ZSWAP_COMPRESSOR_DEFAULT_LZ4
124 default "lz4hc" if ZSWAP_COMPRESSOR_DEF 117 default "lz4hc" if ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
125 default "zstd" if ZSWAP_COMPRESSOR_DEFA 118 default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD
126 default "" 119 default ""
127 120
128 choice 121 choice
129 prompt "Default allocator" 122 prompt "Default allocator"
130 depends on ZSWAP 123 depends on ZSWAP
131 default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC i <<
132 default ZSWAP_ZPOOL_DEFAULT_ZBUD 124 default ZSWAP_ZPOOL_DEFAULT_ZBUD
133 help 125 help
134 Selects the default allocator for th 126 Selects the default allocator for the compressed cache for
135 swap pages. 127 swap pages.
136 The default is 'zbud' for compatibil 128 The default is 'zbud' for compatibility, however please do
137 read the description of each of the 129 read the description of each of the allocators below before
138 making a right choice. 130 making a right choice.
139 131
140 The selection made here can be overr 132 The selection made here can be overridden by using the kernel
141 command line 'zswap.zpool=' option. 133 command line 'zswap.zpool=' option.
142 134
143 config ZSWAP_ZPOOL_DEFAULT_ZBUD 135 config ZSWAP_ZPOOL_DEFAULT_ZBUD
144 bool "zbud" 136 bool "zbud"
145 select ZBUD 137 select ZBUD
146 help 138 help
147 Use the zbud allocator as the defaul 139 Use the zbud allocator as the default allocator.
148 140
149 config ZSWAP_ZPOOL_DEFAULT_Z3FOLD_DEPRECATED !! 141 config ZSWAP_ZPOOL_DEFAULT_Z3FOLD
150 bool "z3foldi (DEPRECATED)" !! 142 bool "z3fold"
151 select Z3FOLD_DEPRECATED !! 143 select Z3FOLD
152 help 144 help
153 Use the z3fold allocator as the defa 145 Use the z3fold allocator as the default allocator.
154 146
155 Deprecated and scheduled for removal <<
156 see CONFIG_Z3FOLD_DEPRECATED. <<
157 <<
158 config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC 147 config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
159 bool "zsmalloc" 148 bool "zsmalloc"
160 select ZSMALLOC 149 select ZSMALLOC
161 help 150 help
162 Use the zsmalloc allocator as the de 151 Use the zsmalloc allocator as the default allocator.
163 endchoice 152 endchoice
164 153
165 config ZSWAP_ZPOOL_DEFAULT 154 config ZSWAP_ZPOOL_DEFAULT
166 string 155 string
167 depends on ZSWAP 156 depends on ZSWAP
168 default "zbud" if ZSWAP_ZPOOL_DEFAULT_Z 157 default "zbud" if ZSWAP_ZPOOL_DEFAULT_ZBUD
169 default "z3fold" if ZSWAP_ZPOOL_DEFAULT !! 158 default "z3fold" if ZSWAP_ZPOOL_DEFAULT_Z3FOLD
170 default "zsmalloc" if ZSWAP_ZPOOL_DEFAU 159 default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
171 default "" 160 default ""
172 161
173 config ZBUD 162 config ZBUD
174 tristate "2:1 compression allocator (z 163 tristate "2:1 compression allocator (zbud)"
175 depends on ZSWAP 164 depends on ZSWAP
176 help 165 help
177 A special purpose allocator for stor 166 A special purpose allocator for storing compressed pages.
178 It is designed to store up to two co 167 It is designed to store up to two compressed pages per physical
179 page. While this design limits stor 168 page. While this design limits storage density, it has simple and
180 deterministic reclaim properties tha 169 deterministic reclaim properties that make it preferable to a higher
181 density approach when reclaim will b 170 density approach when reclaim will be used.
182 171
183 config Z3FOLD_DEPRECATED !! 172 config Z3FOLD
184 tristate "3:1 compression allocator (z !! 173 tristate "3:1 compression allocator (z3fold)"
185 depends on ZSWAP 174 depends on ZSWAP
186 help 175 help
187 Deprecated and scheduled for removal <<
188 a good reason for using Z3FOLD over <<
189 linux-mm@kvack.org and the zswap mai <<
190 <<
191 A special purpose allocator for stor 176 A special purpose allocator for storing compressed pages.
192 It is designed to store up to three 177 It is designed to store up to three compressed pages per physical
193 page. It is a ZBUD derivative so the 178 page. It is a ZBUD derivative so the simplicity and determinism are
194 still there. 179 still there.
195 180
196 config Z3FOLD <<
197 tristate <<
198 default y if Z3FOLD_DEPRECATED=y <<
199 default m if Z3FOLD_DEPRECATED=m <<
200 depends on Z3FOLD_DEPRECATED <<
201 <<
202 config ZSMALLOC 181 config ZSMALLOC
203 tristate 182 tristate
204 prompt "N:1 compression allocator (zsm !! 183 prompt "N:1 compression allocator (zsmalloc)" if ZSWAP
205 depends on MMU 184 depends on MMU
206 help 185 help
207 zsmalloc is a slab-based memory allo 186 zsmalloc is a slab-based memory allocator designed to store
208 pages of various compression levels 187 pages of various compression levels efficiently. It achieves
209 the highest storage density with the 188 the highest storage density with the least amount of fragmentation.
210 189
211 config ZSMALLOC_STAT 190 config ZSMALLOC_STAT
212 bool "Export zsmalloc statistics" 191 bool "Export zsmalloc statistics"
213 depends on ZSMALLOC 192 depends on ZSMALLOC
214 select DEBUG_FS 193 select DEBUG_FS
215 help 194 help
216 This option enables code in the zsma 195 This option enables code in the zsmalloc to collect various
217 statistics about what's happening in 196 statistics about what's happening in zsmalloc and exports that
218 information to userspace via debugfs 197 information to userspace via debugfs.
219 If unsure, say N. 198 If unsure, say N.
220 199
221 config ZSMALLOC_CHAIN_SIZE !! 200 menu "SLAB allocator options"
222 int "Maximum number of physical pages <<
223 default 8 <<
224 range 4 16 <<
225 depends on ZSMALLOC <<
226 help <<
227 This option sets the upper limit on <<
228 that a zmalloc page (zspage) can con <<
229 chain size is calculated for each si <<
230 initialization of the pool. <<
231 <<
232 Changing this option can alter the c <<
233 such as the number of pages per zspa <<
234 per zspage. This can also result in <<
235 the pool, as zsmalloc merges size cl <<
236 characteristics. <<
237 201
238 For more information, see zsmalloc d !! 202 choice
>> 203 prompt "Choose SLAB allocator"
>> 204 default SLUB
>> 205 help
>> 206 This option allows to select a slab allocator.
239 207
240 menu "Slab allocator options" !! 208 config SLAB
>> 209 bool "SLAB"
>> 210 depends on !PREEMPT_RT
>> 211 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 212 help
>> 213 The regular slab allocator that is established and known to work
>> 214 well in all environments. It organizes cache hot objects in
>> 215 per cpu and per node queues.
241 216
242 config SLUB 217 config SLUB
243 def_bool y !! 218 bool "SLUB (Unqueued Allocator)"
>> 219 select HAVE_HARDENED_USERCOPY_ALLOCATOR
>> 220 help
>> 221 SLUB is a slab allocator that minimizes cache line usage
>> 222 instead of managing queues of cached objects (SLAB approach).
>> 223 Per cpu caching is realized using slabs of objects instead
>> 224 of queues of objects. SLUB can use memory efficiently
>> 225 and has enhanced diagnostics. SLUB is the default choice for
>> 226 a slab allocator.
244 227
245 config SLUB_TINY !! 228 config SLOB
246 bool "Configure for minimal memory foo <<
247 depends on EXPERT 229 depends on EXPERT
248 select SLAB_MERGE_DEFAULT !! 230 bool "SLOB (Simple Allocator)"
>> 231 depends on !PREEMPT_RT
249 help 232 help
250 Configures the slab allocator in a !! 233 SLOB replaces the stock allocator with a drastically simpler
251 footprint, sacrificing scalability, !! 234 allocator. SLOB is generally more space efficient but
252 This is intended only for the small !! 235 does not perform as well on large systems.
253 SLOB allocator and is not recommend <<
254 16MB RAM. <<
255 236
256 If unsure, say N. !! 237 endchoice
257 238
258 config SLAB_MERGE_DEFAULT 239 config SLAB_MERGE_DEFAULT
259 bool "Allow slab caches to be merged" 240 bool "Allow slab caches to be merged"
260 default y 241 default y
>> 242 depends on SLAB || SLUB
261 help 243 help
262 For reduced kernel memory fragmentat 244 For reduced kernel memory fragmentation, slab caches can be
263 merged when they share the same size 245 merged when they share the same size and other characteristics.
264 This carries a risk of kernel heap o 246 This carries a risk of kernel heap overflows being able to
265 overwrite objects from merged caches 247 overwrite objects from merged caches (and more easily control
266 cache layout), which makes such heap 248 cache layout), which makes such heap attacks easier to exploit
267 by attackers. By keeping caches unme 249 by attackers. By keeping caches unmerged, these kinds of exploits
268 can usually only damage objects in t 250 can usually only damage objects in the same cache. To disable
269 merging at runtime, "slab_nomerge" c 251 merging at runtime, "slab_nomerge" can be passed on the kernel
270 command line. 252 command line.
271 253
272 config SLAB_FREELIST_RANDOM 254 config SLAB_FREELIST_RANDOM
273 bool "Randomize slab freelist" 255 bool "Randomize slab freelist"
274 depends on !SLUB_TINY !! 256 depends on SLAB || SLUB
275 help 257 help
276 Randomizes the freelist order used o 258 Randomizes the freelist order used on creating new pages. This
277 security feature reduces the predict 259 security feature reduces the predictability of the kernel slab
278 allocator against heap overflows. 260 allocator against heap overflows.
279 261
280 config SLAB_FREELIST_HARDENED 262 config SLAB_FREELIST_HARDENED
281 bool "Harden slab freelist metadata" 263 bool "Harden slab freelist metadata"
282 depends on !SLUB_TINY !! 264 depends on SLAB || SLUB
283 help 265 help
284 Many kernel heap attacks try to targ 266 Many kernel heap attacks try to target slab cache metadata and
285 other infrastructure. This options m 267 other infrastructure. This options makes minor performance
286 sacrifices to harden the kernel slab 268 sacrifices to harden the kernel slab allocator against common
287 freelist exploit methods. !! 269 freelist exploit methods. Some slab implementations have more
288 !! 270 sanity-checking than others. This option is most effective with
289 config SLAB_BUCKETS !! 271 CONFIG_SLUB.
290 bool "Support allocation from separate <<
291 depends on !SLUB_TINY <<
292 default SLAB_FREELIST_HARDENED <<
293 help <<
294 Kernel heap attacks frequently depen <<
295 specifically-sized allocations with <<
296 that will be allocated into the same <<
297 target object. To avoid sharing thes <<
298 provide an explicitly separated set <<
299 user-controlled allocations. This ma <<
300 memory fragmentation, though in prac <<
301 of extra pages since the bulk of use <<
302 are relatively long-lived. <<
303 <<
304 If unsure, say Y. <<
305 272
306 config SLUB_STATS 273 config SLUB_STATS
307 default n 274 default n
308 bool "Enable performance statistics" !! 275 bool "Enable SLUB performance statistics"
309 depends on SYSFS && !SLUB_TINY !! 276 depends on SLUB && SYSFS
310 help 277 help
311 The statistics are useful to debug s !! 278 SLUB statistics are useful to debug SLUBs allocation behavior in
312 order find ways to optimize the allo 279 order find ways to optimize the allocator. This should never be
313 enabled for production use since kee 280 enabled for production use since keeping statistics slows down
314 the allocator by a few percentage po 281 the allocator by a few percentage points. The slabinfo command
315 supports the determination of the mo 282 supports the determination of the most active slabs to figure
316 out which slabs are relevant to a pa 283 out which slabs are relevant to a particular load.
317 Try running: slabinfo -DA 284 Try running: slabinfo -DA
318 285
319 config SLUB_CPU_PARTIAL 286 config SLUB_CPU_PARTIAL
320 default y 287 default y
321 depends on SMP && !SLUB_TINY !! 288 depends on SLUB && SMP
322 bool "Enable per cpu partial caches" !! 289 bool "SLUB per cpu partial cache"
323 help 290 help
324 Per cpu partial caches accelerate ob 291 Per cpu partial caches accelerate objects allocation and freeing
325 that is local to a processor at the 292 that is local to a processor at the price of more indeterminism
326 in the latency of the free. On overf 293 in the latency of the free. On overflow these caches will be cleared
327 which requires the taking of locks t 294 which requires the taking of locks that may cause latency spikes.
328 Typically one would choose no for a 295 Typically one would choose no for a realtime system.
329 296
330 config RANDOM_KMALLOC_CACHES !! 297 endmenu # SLAB allocator options
331 default n <<
332 depends on !SLUB_TINY <<
333 bool "Randomize slab caches for normal <<
334 help <<
335 A hardening feature that creates mul <<
336 normal kmalloc allocation and makes <<
337 on code address, which makes the att <<
338 vulnerable memory objects on the hea <<
339 memory vulnerabilities. <<
340 <<
341 Currently the number of copies is se <<
342 that effectively diverges the memory <<
343 subsystems or modules into different <<
344 limited degree of memory and CPU ove <<
345 system workload. <<
346 <<
347 endmenu # Slab allocator options <<
348 298
349 config SHUFFLE_PAGE_ALLOCATOR 299 config SHUFFLE_PAGE_ALLOCATOR
350 bool "Page allocator randomization" 300 bool "Page allocator randomization"
351 default SLAB_FREELIST_RANDOM && ACPI_N 301 default SLAB_FREELIST_RANDOM && ACPI_NUMA
352 help 302 help
353 Randomization of the page allocator 303 Randomization of the page allocator improves the average
354 utilization of a direct-mapped memor 304 utilization of a direct-mapped memory-side-cache. See section
355 5.2.27 Heterogeneous Memory Attribut 305 5.2.27 Heterogeneous Memory Attribute Table (HMAT) in the ACPI
356 6.2a specification for an example of 306 6.2a specification for an example of how a platform advertises
357 the presence of a memory-side-cache. 307 the presence of a memory-side-cache. There are also incidental
358 security benefits as it reduces the 308 security benefits as it reduces the predictability of page
359 allocations to compliment SLAB_FREEL 309 allocations to compliment SLAB_FREELIST_RANDOM, but the
360 default granularity of shuffling on !! 310 default granularity of shuffling on the "MAX_ORDER - 1" i.e,
361 order of pages is selected based on !! 311 10th order of pages is selected based on cache utilization
362 on x86. !! 312 benefits on x86.
363 313
364 While the randomization improves cac 314 While the randomization improves cache utilization it may
365 negatively impact workloads on platf 315 negatively impact workloads on platforms without a cache. For
366 this reason, by default, the randomi !! 316 this reason, by default, the randomization is enabled only
367 if SHUFFLE_PAGE_ALLOCATOR=y. The ran !! 317 after runtime detection of a direct-mapped memory-side-cache.
368 with the 'page_alloc.shuffle' kernel !! 318 Otherwise, the randomization may be force enabled with the
>> 319 'page_alloc.shuffle' kernel command line parameter.
369 320
370 Say Y if unsure. 321 Say Y if unsure.
371 322
372 config COMPAT_BRK 323 config COMPAT_BRK
373 bool "Disable heap randomization" 324 bool "Disable heap randomization"
374 default y 325 default y
375 help 326 help
376 Randomizing heap placement makes hea 327 Randomizing heap placement makes heap exploits harder, but it
377 also breaks ancient binaries (includ 328 also breaks ancient binaries (including anything libc5 based).
378 This option changes the bootup defau 329 This option changes the bootup default to heap randomization
379 disabled, and can be overridden at r 330 disabled, and can be overridden at runtime by setting
380 /proc/sys/kernel/randomize_va_space 331 /proc/sys/kernel/randomize_va_space to 2.
381 332
382 On non-ancient distros (post-2000 on 333 On non-ancient distros (post-2000 ones) N is usually a safe choice.
383 334
384 config MMAP_ALLOW_UNINITIALIZED 335 config MMAP_ALLOW_UNINITIALIZED
385 bool "Allow mmapped anonymous memory t 336 bool "Allow mmapped anonymous memory to be uninitialized"
386 depends on EXPERT && !MMU 337 depends on EXPERT && !MMU
387 default n 338 default n
388 help 339 help
389 Normally, and according to the Linux 340 Normally, and according to the Linux spec, anonymous memory obtained
390 from mmap() has its contents cleared 341 from mmap() has its contents cleared before it is passed to
391 userspace. Enabling this config opt 342 userspace. Enabling this config option allows you to request that
392 mmap() skip that if it is given an M 343 mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
393 providing a huge performance boost. 344 providing a huge performance boost. If this option is not enabled,
394 then the flag will be ignored. 345 then the flag will be ignored.
395 346
396 This is taken advantage of by uClibc 347 This is taken advantage of by uClibc's malloc(), and also by
397 ELF-FDPIC binfmt's brk and stack all 348 ELF-FDPIC binfmt's brk and stack allocator.
398 349
399 Because of the obvious security issu 350 Because of the obvious security issues, this option should only be
400 enabled on embedded devices where yo 351 enabled on embedded devices where you control what is run in
401 userspace. Since that isn't general 352 userspace. Since that isn't generally a problem on no-MMU systems,
402 it is normally safe to say Y here. 353 it is normally safe to say Y here.
403 354
404 See Documentation/admin-guide/mm/nom 355 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
405 356
406 config SELECT_MEMORY_MODEL 357 config SELECT_MEMORY_MODEL
407 def_bool y 358 def_bool y
408 depends on ARCH_SELECT_MEMORY_MODEL 359 depends on ARCH_SELECT_MEMORY_MODEL
409 360
410 choice 361 choice
411 prompt "Memory model" 362 prompt "Memory model"
412 depends on SELECT_MEMORY_MODEL 363 depends on SELECT_MEMORY_MODEL
413 default SPARSEMEM_MANUAL if ARCH_SPARS 364 default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
414 default FLATMEM_MANUAL 365 default FLATMEM_MANUAL
415 help 366 help
416 This option allows you to change som 367 This option allows you to change some of the ways that
417 Linux manages its memory internally. 368 Linux manages its memory internally. Most users will
418 only have one option here selected b 369 only have one option here selected by the architecture
419 configuration. This is normal. 370 configuration. This is normal.
420 371
421 config FLATMEM_MANUAL 372 config FLATMEM_MANUAL
422 bool "Flat Memory" 373 bool "Flat Memory"
423 depends on !ARCH_SPARSEMEM_ENABLE || A 374 depends on !ARCH_SPARSEMEM_ENABLE || ARCH_FLATMEM_ENABLE
424 help 375 help
425 This option is best suited for non-N 376 This option is best suited for non-NUMA systems with
426 flat address space. The FLATMEM is t 377 flat address space. The FLATMEM is the most efficient
427 system in terms of performance and r 378 system in terms of performance and resource consumption
428 and it is the best option for smalle 379 and it is the best option for smaller systems.
429 380
430 For systems that have holes in their 381 For systems that have holes in their physical address
431 spaces and for features like NUMA an 382 spaces and for features like NUMA and memory hotplug,
432 choose "Sparse Memory". 383 choose "Sparse Memory".
433 384
434 If unsure, choose this option (Flat 385 If unsure, choose this option (Flat Memory) over any other.
435 386
436 config SPARSEMEM_MANUAL 387 config SPARSEMEM_MANUAL
437 bool "Sparse Memory" 388 bool "Sparse Memory"
438 depends on ARCH_SPARSEMEM_ENABLE 389 depends on ARCH_SPARSEMEM_ENABLE
439 help 390 help
440 This will be the only option for som 391 This will be the only option for some systems, including
441 memory hot-plug systems. This is no 392 memory hot-plug systems. This is normal.
442 393
443 This option provides efficient suppo 394 This option provides efficient support for systems with
444 holes is their physical address spac 395 holes is their physical address space and allows memory
445 hot-plug and hot-remove. 396 hot-plug and hot-remove.
446 397
447 If unsure, choose "Flat Memory" over 398 If unsure, choose "Flat Memory" over this option.
448 399
449 endchoice 400 endchoice
450 401
451 config SPARSEMEM 402 config SPARSEMEM
452 def_bool y 403 def_bool y
453 depends on (!SELECT_MEMORY_MODEL && AR 404 depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL
454 405
455 config FLATMEM 406 config FLATMEM
456 def_bool y 407 def_bool y
457 depends on !SPARSEMEM || FLATMEM_MANUA 408 depends on !SPARSEMEM || FLATMEM_MANUAL
458 409
459 # 410 #
460 # SPARSEMEM_EXTREME (which is the default) doe 411 # SPARSEMEM_EXTREME (which is the default) does some bootmem
461 # allocations when sparse_init() is called. I 412 # allocations when sparse_init() is called. If this cannot
462 # be done on your architecture, select this op 413 # be done on your architecture, select this option. However,
463 # statically allocating the mem_section[] arra 414 # statically allocating the mem_section[] array can potentially
464 # consume vast quantities of .bss, so be caref 415 # consume vast quantities of .bss, so be careful.
465 # 416 #
466 # This option will also potentially produce sm 417 # This option will also potentially produce smaller runtime code
467 # with gcc 3.4 and later. 418 # with gcc 3.4 and later.
468 # 419 #
469 config SPARSEMEM_STATIC 420 config SPARSEMEM_STATIC
470 bool 421 bool
471 422
472 # 423 #
473 # Architecture platforms which require a two l 424 # Architecture platforms which require a two level mem_section in SPARSEMEM
474 # must select this option. This is usually for 425 # must select this option. This is usually for architecture platforms with
475 # an extremely sparse physical address space. 426 # an extremely sparse physical address space.
476 # 427 #
477 config SPARSEMEM_EXTREME 428 config SPARSEMEM_EXTREME
478 def_bool y 429 def_bool y
479 depends on SPARSEMEM && !SPARSEMEM_STA 430 depends on SPARSEMEM && !SPARSEMEM_STATIC
480 431
481 config SPARSEMEM_VMEMMAP_ENABLE 432 config SPARSEMEM_VMEMMAP_ENABLE
482 bool 433 bool
483 434
484 config SPARSEMEM_VMEMMAP 435 config SPARSEMEM_VMEMMAP
485 bool "Sparse Memory virtual memmap" 436 bool "Sparse Memory virtual memmap"
486 depends on SPARSEMEM && SPARSEMEM_VMEM 437 depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
487 default y 438 default y
488 help 439 help
489 SPARSEMEM_VMEMMAP uses a virtually m 440 SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
490 pfn_to_page and page_to_pfn operatio 441 pfn_to_page and page_to_pfn operations. This is the most
491 efficient option when sufficient ker 442 efficient option when sufficient kernel resources are available.
492 # <<
493 # Select this config option from the architect <<
494 # to enable the feature of HugeTLB/dev_dax vme <<
495 # <<
496 config ARCH_WANT_OPTIMIZE_DAX_VMEMMAP <<
497 bool <<
498 <<
499 config ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP <<
500 bool <<
501 443
502 config HAVE_MEMBLOCK_PHYS_MAP 444 config HAVE_MEMBLOCK_PHYS_MAP
503 bool 445 bool
504 446
505 config HAVE_GUP_FAST !! 447 config HAVE_FAST_GUP
506 depends on MMU 448 depends on MMU
507 bool 449 bool
508 450
509 # Don't discard allocated memory used to track 451 # Don't discard allocated memory used to track "memory" and "reserved" memblocks
510 # after early boot, so it can still be used to 452 # after early boot, so it can still be used to test for validity of memory.
511 # Also, memblocks are updated with memory hot( 453 # Also, memblocks are updated with memory hot(un)plug.
512 config ARCH_KEEP_MEMBLOCK 454 config ARCH_KEEP_MEMBLOCK
513 bool 455 bool
514 456
515 # Keep arch NUMA mapping infrastructure post-i 457 # Keep arch NUMA mapping infrastructure post-init.
516 config NUMA_KEEP_MEMINFO 458 config NUMA_KEEP_MEMINFO
517 bool 459 bool
518 460
519 config MEMORY_ISOLATION 461 config MEMORY_ISOLATION
520 bool 462 bool
521 463
522 # IORESOURCE_SYSTEM_RAM regions in the kernel 464 # IORESOURCE_SYSTEM_RAM regions in the kernel resource tree that are marked
523 # IORESOURCE_EXCLUSIVE cannot be mapped to use 465 # IORESOURCE_EXCLUSIVE cannot be mapped to user space, for example, via
524 # /dev/mem. 466 # /dev/mem.
525 config EXCLUSIVE_SYSTEM_RAM 467 config EXCLUSIVE_SYSTEM_RAM
526 def_bool y 468 def_bool y
527 depends on !DEVMEM || STRICT_DEVMEM 469 depends on !DEVMEM || STRICT_DEVMEM
528 470
529 # 471 #
530 # Only be set on architectures that have compl 472 # Only be set on architectures that have completely implemented memory hotplug
531 # feature. If you are not sure, don't touch it 473 # feature. If you are not sure, don't touch it.
532 # 474 #
533 config HAVE_BOOTMEM_INFO_NODE 475 config HAVE_BOOTMEM_INFO_NODE
534 def_bool n 476 def_bool n
535 477
536 config ARCH_ENABLE_MEMORY_HOTPLUG 478 config ARCH_ENABLE_MEMORY_HOTPLUG
537 bool 479 bool
538 480
539 config ARCH_ENABLE_MEMORY_HOTREMOVE 481 config ARCH_ENABLE_MEMORY_HOTREMOVE
540 bool 482 bool
541 483
542 # eventually, we can have this option just 'se 484 # eventually, we can have this option just 'select SPARSEMEM'
543 menuconfig MEMORY_HOTPLUG 485 menuconfig MEMORY_HOTPLUG
544 bool "Memory hotplug" 486 bool "Memory hotplug"
545 select MEMORY_ISOLATION 487 select MEMORY_ISOLATION
546 depends on SPARSEMEM 488 depends on SPARSEMEM
547 depends on ARCH_ENABLE_MEMORY_HOTPLUG 489 depends on ARCH_ENABLE_MEMORY_HOTPLUG
548 depends on 64BIT 490 depends on 64BIT
549 select NUMA_KEEP_MEMINFO if NUMA 491 select NUMA_KEEP_MEMINFO if NUMA
550 492
551 if MEMORY_HOTPLUG 493 if MEMORY_HOTPLUG
552 494
553 config MEMORY_HOTPLUG_DEFAULT_ONLINE 495 config MEMORY_HOTPLUG_DEFAULT_ONLINE
554 bool "Online the newly added memory bl 496 bool "Online the newly added memory blocks by default"
555 depends on MEMORY_HOTPLUG 497 depends on MEMORY_HOTPLUG
556 help 498 help
557 This option sets the default policy 499 This option sets the default policy setting for memory hotplug
558 onlining policy (/sys/devices/system 500 onlining policy (/sys/devices/system/memory/auto_online_blocks) which
559 determines what happens to newly add 501 determines what happens to newly added memory regions. Policy setting
560 can always be changed at runtime. 502 can always be changed at runtime.
561 See Documentation/admin-guide/mm/mem 503 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
562 504
563 Say Y here if you want all hot-plugg 505 Say Y here if you want all hot-plugged memory blocks to appear in
564 'online' state by default. 506 'online' state by default.
565 Say N here if you want the default p 507 Say N here if you want the default policy to keep all hot-plugged
566 memory blocks in 'offline' state. 508 memory blocks in 'offline' state.
567 509
568 config MEMORY_HOTREMOVE 510 config MEMORY_HOTREMOVE
569 bool "Allow for memory hot remove" 511 bool "Allow for memory hot remove"
570 select HAVE_BOOTMEM_INFO_NODE if (X86_ 512 select HAVE_BOOTMEM_INFO_NODE if (X86_64 || PPC64)
571 depends on MEMORY_HOTPLUG && ARCH_ENAB 513 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
572 depends on MIGRATION 514 depends on MIGRATION
573 515
574 config MHP_MEMMAP_ON_MEMORY 516 config MHP_MEMMAP_ON_MEMORY
575 def_bool y 517 def_bool y
576 depends on MEMORY_HOTPLUG && SPARSEMEM 518 depends on MEMORY_HOTPLUG && SPARSEMEM_VMEMMAP
577 depends on ARCH_MHP_MEMMAP_ON_MEMORY_E 519 depends on ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
578 520
579 endif # MEMORY_HOTPLUG 521 endif # MEMORY_HOTPLUG
580 522
581 config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE <<
582 bool <<
583 <<
584 # Heavily threaded applications may benefit fr 523 # Heavily threaded applications may benefit from splitting the mm-wide
585 # page_table_lock, so that faults on different 524 # page_table_lock, so that faults on different parts of the user address
586 # space can be handled with less contention: s 525 # space can be handled with less contention: split it at this NR_CPUS.
587 # Default to 4 for wider testing, though 8 mig 526 # Default to 4 for wider testing, though 8 might be more appropriate.
588 # ARM's adjust_pte (unused if VIPT) depends on 527 # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
589 # PA-RISC 7xxx's spinlock_t would enlarge stru 528 # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
590 # SPARC32 allocates multiple pte tables within 529 # SPARC32 allocates multiple pte tables within a single page, and therefore
591 # a per-page lock leads to problems when multi 530 # a per-page lock leads to problems when multiple tables need to be locked
592 # at the same time (e.g. copy_page_range()). 531 # at the same time (e.g. copy_page_range()).
593 # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock 532 # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
594 # 533 #
595 config SPLIT_PTE_PTLOCKS !! 534 config SPLIT_PTLOCK_CPUS
596 def_bool y !! 535 int
597 depends on MMU !! 536 default "999999" if !MMU
598 depends on SMP !! 537 default "999999" if ARM && !CPU_CACHE_VIPT
599 depends on NR_CPUS >= 4 !! 538 default "999999" if PARISC && !PA20
600 depends on !ARM || CPU_CACHE_VIPT !! 539 default "999999" if SPARC32
601 depends on !PARISC || PA20 !! 540 default "4"
602 depends on !SPARC32 <<
603 541
604 config ARCH_ENABLE_SPLIT_PMD_PTLOCK 542 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
605 bool 543 bool
606 544
607 config SPLIT_PMD_PTLOCKS <<
608 def_bool y <<
609 depends on SPLIT_PTE_PTLOCKS && ARCH_E <<
610 <<
611 # 545 #
612 # support for memory balloon 546 # support for memory balloon
613 config MEMORY_BALLOON 547 config MEMORY_BALLOON
614 bool 548 bool
615 549
616 # 550 #
617 # support for memory balloon compaction 551 # support for memory balloon compaction
618 config BALLOON_COMPACTION 552 config BALLOON_COMPACTION
619 bool "Allow for balloon memory compact 553 bool "Allow for balloon memory compaction/migration"
620 default y !! 554 def_bool y
621 depends on COMPACTION && MEMORY_BALLOO 555 depends on COMPACTION && MEMORY_BALLOON
622 help 556 help
623 Memory fragmentation introduced by b 557 Memory fragmentation introduced by ballooning might reduce
624 significantly the number of 2MB cont 558 significantly the number of 2MB contiguous memory blocks that can be
625 used within a guest, thus imposing p 559 used within a guest, thus imposing performance penalties associated
626 with the reduced number of transpare 560 with the reduced number of transparent huge pages that could be used
627 by the guest workload. Allowing the 561 by the guest workload. Allowing the compaction & migration for memory
628 pages enlisted as being part of memo 562 pages enlisted as being part of memory balloon devices avoids the
629 scenario aforementioned and helps im 563 scenario aforementioned and helps improving memory defragmentation.
630 564
631 # 565 #
632 # support for memory compaction 566 # support for memory compaction
633 config COMPACTION 567 config COMPACTION
634 bool "Allow for memory compaction" 568 bool "Allow for memory compaction"
635 default y !! 569 def_bool y
636 select MIGRATION 570 select MIGRATION
637 depends on MMU 571 depends on MMU
638 help 572 help
639 Compaction is the only memory manage 573 Compaction is the only memory management component to form
640 high order (larger physically contig 574 high order (larger physically contiguous) memory blocks
641 reliably. The page allocator relies 575 reliably. The page allocator relies on compaction heavily and
642 the lack of the feature can lead to 576 the lack of the feature can lead to unexpected OOM killer
643 invocations for high order memory re 577 invocations for high order memory requests. You shouldn't
644 disable this option unless there rea 578 disable this option unless there really is a strong reason for
645 it and then we would be really inter 579 it and then we would be really interested to hear about that at
646 linux-mm@kvack.org. 580 linux-mm@kvack.org.
647 581
648 config COMPACT_UNEVICTABLE_DEFAULT <<
649 int <<
650 depends on COMPACTION <<
651 default 0 if PREEMPT_RT <<
652 default 1 <<
653 <<
654 # 582 #
655 # support for free page reporting 583 # support for free page reporting
656 config PAGE_REPORTING 584 config PAGE_REPORTING
657 bool "Free page reporting" 585 bool "Free page reporting"
>> 586 def_bool n
658 help 587 help
659 Free page reporting allows for the i 588 Free page reporting allows for the incremental acquisition of
660 free pages from the buddy allocator 589 free pages from the buddy allocator for the purpose of reporting
661 those pages to another entity, such 590 those pages to another entity, such as a hypervisor, so that the
662 memory can be freed within the host 591 memory can be freed within the host for other uses.
663 592
664 # 593 #
665 # support for page migration 594 # support for page migration
666 # 595 #
667 config MIGRATION 596 config MIGRATION
668 bool "Page migration" 597 bool "Page migration"
669 default y !! 598 def_bool y
670 depends on (NUMA || ARCH_ENABLE_MEMORY 599 depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
671 help 600 help
672 Allows the migration of the physical 601 Allows the migration of the physical location of pages of processes
673 while the virtual addresses are not 602 while the virtual addresses are not changed. This is useful in
674 two situations. The first is on NUMA 603 two situations. The first is on NUMA systems to put pages nearer
675 to the processors accessing. The sec 604 to the processors accessing. The second is when allocating huge
676 pages as migration can relocate page 605 pages as migration can relocate pages to satisfy a huge page
677 allocation instead of reclaiming. 606 allocation instead of reclaiming.
678 607
679 config DEVICE_MIGRATION 608 config DEVICE_MIGRATION
680 def_bool MIGRATION && ZONE_DEVICE 609 def_bool MIGRATION && ZONE_DEVICE
681 610
682 config ARCH_ENABLE_HUGEPAGE_MIGRATION 611 config ARCH_ENABLE_HUGEPAGE_MIGRATION
683 bool 612 bool
684 613
685 config ARCH_ENABLE_THP_MIGRATION 614 config ARCH_ENABLE_THP_MIGRATION
686 bool 615 bool
687 616
688 config HUGETLB_PAGE_SIZE_VARIABLE 617 config HUGETLB_PAGE_SIZE_VARIABLE
689 def_bool n 618 def_bool n
690 help 619 help
691 Allows the pageblock_order value to 620 Allows the pageblock_order value to be dynamic instead of just standard
692 HUGETLB_PAGE_ORDER when there are mu 621 HUGETLB_PAGE_ORDER when there are multiple HugeTLB page sizes available
693 on a platform. 622 on a platform.
694 623
695 Note that the pageblock_order cannot !! 624 Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
696 clamped down to MAX_PAGE_ORDER. !! 625 clamped down to MAX_ORDER - 1.
697 626
698 config CONTIG_ALLOC 627 config CONTIG_ALLOC
699 def_bool (MEMORY_ISOLATION && COMPACTI 628 def_bool (MEMORY_ISOLATION && COMPACTION) || CMA
700 629
701 config PCP_BATCH_SCALE_MAX <<
702 int "Maximum scale factor of PCP (Per- <<
703 default 5 <<
704 range 0 6 <<
705 help <<
706 In page allocator, PCP (Per-CPU page <<
707 batches. The batch number is scaled <<
708 allocation/free throughput. But too <<
709 latency. This option sets the upper <<
710 the maximum latency. <<
711 <<
712 config PHYS_ADDR_T_64BIT 630 config PHYS_ADDR_T_64BIT
713 def_bool 64BIT 631 def_bool 64BIT
714 632
715 config BOUNCE 633 config BOUNCE
716 bool "Enable bounce buffers" 634 bool "Enable bounce buffers"
717 default y 635 default y
718 depends on BLOCK && MMU && HIGHMEM 636 depends on BLOCK && MMU && HIGHMEM
719 help 637 help
720 Enable bounce buffers for devices th 638 Enable bounce buffers for devices that cannot access the full range of
721 memory available to the CPU. Enabled 639 memory available to the CPU. Enabled by default when HIGHMEM is
722 selected, but you may say n to overr 640 selected, but you may say n to override this.
723 641
724 config MMU_NOTIFIER 642 config MMU_NOTIFIER
725 bool 643 bool
>> 644 select SRCU
726 select INTERVAL_TREE 645 select INTERVAL_TREE
727 646
728 config KSM 647 config KSM
729 bool "Enable KSM for page merging" 648 bool "Enable KSM for page merging"
730 depends on MMU 649 depends on MMU
731 select XXHASH 650 select XXHASH
732 help 651 help
733 Enable Kernel Samepage Merging: KSM 652 Enable Kernel Samepage Merging: KSM periodically scans those areas
734 of an application's address space th 653 of an application's address space that an app has advised may be
735 mergeable. When it finds pages of i 654 mergeable. When it finds pages of identical content, it replaces
736 the many instances by a single page 655 the many instances by a single page with that content, so
737 saving memory until one or another a 656 saving memory until one or another app needs to modify the content.
738 Recommended for use with KVM, or wit 657 Recommended for use with KVM, or with other duplicative applications.
739 See Documentation/mm/ksm.rst for mor 658 See Documentation/mm/ksm.rst for more information: KSM is inactive
740 until a program has madvised that an 659 until a program has madvised that an area is MADV_MERGEABLE, and
741 root has set /sys/kernel/mm/ksm/run 660 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
742 661
743 config DEFAULT_MMAP_MIN_ADDR 662 config DEFAULT_MMAP_MIN_ADDR
744 int "Low address space to protect from 663 int "Low address space to protect from user allocation"
745 depends on MMU 664 depends on MMU
746 default 4096 665 default 4096
747 help 666 help
748 This is the portion of low virtual m 667 This is the portion of low virtual memory which should be protected
749 from userspace allocation. Keeping 668 from userspace allocation. Keeping a user from writing to low pages
750 can help reduce the impact of kernel 669 can help reduce the impact of kernel NULL pointer bugs.
751 670
752 For most arm64, ppc64 and x86 users !! 671 For most ia64, ppc64 and x86 users with lots of address space
753 a value of 65536 is reasonable and s 672 a value of 65536 is reasonable and should cause no problems.
754 On arm and other archs it should not 673 On arm and other archs it should not be higher than 32768.
755 Programs which use vm86 functionalit 674 Programs which use vm86 functionality or have some need to map
756 this low address space will need CAP 675 this low address space will need CAP_SYS_RAWIO or disable this
757 protection by setting the value to 0 676 protection by setting the value to 0.
758 677
759 This value can be changed after boot 678 This value can be changed after boot using the
760 /proc/sys/vm/mmap_min_addr tunable. 679 /proc/sys/vm/mmap_min_addr tunable.
761 680
762 config ARCH_SUPPORTS_MEMORY_FAILURE 681 config ARCH_SUPPORTS_MEMORY_FAILURE
763 bool 682 bool
764 683
765 config MEMORY_FAILURE 684 config MEMORY_FAILURE
766 depends on MMU 685 depends on MMU
767 depends on ARCH_SUPPORTS_MEMORY_FAILUR 686 depends on ARCH_SUPPORTS_MEMORY_FAILURE
768 bool "Enable recovery from hardware me 687 bool "Enable recovery from hardware memory errors"
769 select MEMORY_ISOLATION 688 select MEMORY_ISOLATION
770 select RAS 689 select RAS
771 help 690 help
772 Enables code to recover from some me 691 Enables code to recover from some memory failures on systems
773 with MCA recovery. This allows a sys 692 with MCA recovery. This allows a system to continue running
774 even when some of its memory has unc 693 even when some of its memory has uncorrected errors. This requires
775 special hardware support and typical 694 special hardware support and typically ECC memory.
776 695
777 config HWPOISON_INJECT 696 config HWPOISON_INJECT
778 tristate "HWPoison pages injector" 697 tristate "HWPoison pages injector"
779 depends on MEMORY_FAILURE && DEBUG_KER 698 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
780 select PROC_PAGE_MONITOR 699 select PROC_PAGE_MONITOR
781 700
782 config NOMMU_INITIAL_TRIM_EXCESS 701 config NOMMU_INITIAL_TRIM_EXCESS
783 int "Turn on mmap() excess space trimm 702 int "Turn on mmap() excess space trimming before booting"
784 depends on !MMU 703 depends on !MMU
785 default 1 704 default 1
786 help 705 help
787 The NOMMU mmap() frequently needs to 706 The NOMMU mmap() frequently needs to allocate large contiguous chunks
788 of memory on which to store mappings 707 of memory on which to store mappings, but it can only ask the system
789 allocator for chunks in 2^N*PAGE_SIZ 708 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
790 more than it requires. To deal with 709 more than it requires. To deal with this, mmap() is able to trim off
791 the excess and return it to the allo 710 the excess and return it to the allocator.
792 711
793 If trimming is enabled, the excess i 712 If trimming is enabled, the excess is trimmed off and returned to the
794 system allocator, which can cause ex 713 system allocator, which can cause extra fragmentation, particularly
795 if there are a lot of transient proc 714 if there are a lot of transient processes.
796 715
797 If trimming is disabled, the excess 716 If trimming is disabled, the excess is kept, but not used, which for
798 long-term mappings means that the sp 717 long-term mappings means that the space is wasted.
799 718
800 Trimming can be dynamically controll 719 Trimming can be dynamically controlled through a sysctl option
801 (/proc/sys/vm/nr_trim_pages) which s 720 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
802 excess pages there must be before tr 721 excess pages there must be before trimming should occur, or zero if
803 no trimming is to occur. 722 no trimming is to occur.
804 723
805 This option specifies the initial va 724 This option specifies the initial value of this option. The default
806 of 1 says that all excess pages shou 725 of 1 says that all excess pages should be trimmed.
807 726
808 See Documentation/admin-guide/mm/nom 727 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
809 728
810 config ARCH_WANT_GENERAL_HUGETLB 729 config ARCH_WANT_GENERAL_HUGETLB
811 bool 730 bool
812 731
813 config ARCH_WANTS_THP_SWAP 732 config ARCH_WANTS_THP_SWAP
814 def_bool n 733 def_bool n
815 734
816 menuconfig TRANSPARENT_HUGEPAGE 735 menuconfig TRANSPARENT_HUGEPAGE
817 bool "Transparent Hugepage Support" 736 bool "Transparent Hugepage Support"
818 depends on HAVE_ARCH_TRANSPARENT_HUGEP 737 depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT
819 select COMPACTION 738 select COMPACTION
820 select XARRAY_MULTI 739 select XARRAY_MULTI
821 help 740 help
822 Transparent Hugepages allows the ker 741 Transparent Hugepages allows the kernel to use huge pages and
823 huge tlb transparently to the applic 742 huge tlb transparently to the applications whenever possible.
824 This feature can improve computing p 743 This feature can improve computing performance to certain
825 applications by speeding up page fau 744 applications by speeding up page faults during memory
826 allocation, by reducing the number o 745 allocation, by reducing the number of tlb misses and by speeding
827 up the pagetable walking. 746 up the pagetable walking.
828 747
829 If memory constrained on embedded, y 748 If memory constrained on embedded, you may want to say N.
830 749
831 if TRANSPARENT_HUGEPAGE 750 if TRANSPARENT_HUGEPAGE
832 751
833 choice 752 choice
834 prompt "Transparent Hugepage Support s 753 prompt "Transparent Hugepage Support sysfs defaults"
835 depends on TRANSPARENT_HUGEPAGE 754 depends on TRANSPARENT_HUGEPAGE
836 default TRANSPARENT_HUGEPAGE_ALWAYS 755 default TRANSPARENT_HUGEPAGE_ALWAYS
837 help 756 help
838 Selects the sysfs defaults for Trans 757 Selects the sysfs defaults for Transparent Hugepage Support.
839 758
840 config TRANSPARENT_HUGEPAGE_ALWAYS 759 config TRANSPARENT_HUGEPAGE_ALWAYS
841 bool "always" 760 bool "always"
842 help 761 help
843 Enabling Transparent Hugepage always 762 Enabling Transparent Hugepage always, can increase the
844 memory footprint of applications wit 763 memory footprint of applications without a guaranteed
845 benefit but it will work automatical 764 benefit but it will work automatically for all applications.
846 765
847 config TRANSPARENT_HUGEPAGE_MADVISE 766 config TRANSPARENT_HUGEPAGE_MADVISE
848 bool "madvise" 767 bool "madvise"
849 help 768 help
850 Enabling Transparent Hugepage madvis 769 Enabling Transparent Hugepage madvise, will only provide a
851 performance improvement benefit to t 770 performance improvement benefit to the applications using
852 madvise(MADV_HUGEPAGE) but it won't 771 madvise(MADV_HUGEPAGE) but it won't risk to increase the
853 memory footprint of applications wit 772 memory footprint of applications without a guaranteed
854 benefit. 773 benefit.
855 <<
856 config TRANSPARENT_HUGEPAGE_NEVER <<
857 bool "never" <<
858 help <<
859 Disable Transparent Hugepage by defa <<
860 enabled at runtime via sysfs. <<
861 endchoice 774 endchoice
862 775
863 config THP_SWAP 776 config THP_SWAP
864 def_bool y 777 def_bool y
865 depends on TRANSPARENT_HUGEPAGE && ARC !! 778 depends on TRANSPARENT_HUGEPAGE && ARCH_WANTS_THP_SWAP && SWAP
866 help 779 help
867 Swap transparent huge pages in one p 780 Swap transparent huge pages in one piece, without splitting.
868 XXX: For now, swap cluster backing t 781 XXX: For now, swap cluster backing transparent huge page
869 will be split after swapout. 782 will be split after swapout.
870 783
871 For selection by architectures with 784 For selection by architectures with reasonable THP sizes.
872 785
873 config READ_ONLY_THP_FOR_FS 786 config READ_ONLY_THP_FOR_FS
874 bool "Read-only THP for filesystems (E 787 bool "Read-only THP for filesystems (EXPERIMENTAL)"
875 depends on TRANSPARENT_HUGEPAGE && SHM 788 depends on TRANSPARENT_HUGEPAGE && SHMEM
876 789
877 help 790 help
878 Allow khugepaged to put read-only fi 791 Allow khugepaged to put read-only file-backed pages in THP.
879 792
880 This is marked experimental because 793 This is marked experimental because it is a new feature. Write
881 support of file THPs will be develop 794 support of file THPs will be developed in the next few release
882 cycles. 795 cycles.
883 796
884 endif # TRANSPARENT_HUGEPAGE 797 endif # TRANSPARENT_HUGEPAGE
885 798
886 # 799 #
887 # The architecture supports pgtable leaves tha <<
888 # <<
889 config PGTABLE_HAS_HUGE_LEAVES <<
890 def_bool TRANSPARENT_HUGEPAGE || HUGET <<
891 <<
892 # TODO: Allow to be enabled without THP <<
893 config ARCH_SUPPORTS_HUGE_PFNMAP <<
894 def_bool n <<
895 depends on TRANSPARENT_HUGEPAGE <<
896 <<
897 config ARCH_SUPPORTS_PMD_PFNMAP <<
898 def_bool y <<
899 depends on ARCH_SUPPORTS_HUGE_PFNMAP & <<
900 <<
901 config ARCH_SUPPORTS_PUD_PFNMAP <<
902 def_bool y <<
903 depends on ARCH_SUPPORTS_HUGE_PFNMAP & <<
904 <<
905 # <<
906 # UP and nommu archs use km based percpu alloc 800 # UP and nommu archs use km based percpu allocator
907 # 801 #
908 config NEED_PER_CPU_KM 802 config NEED_PER_CPU_KM
909 depends on !SMP || !MMU 803 depends on !SMP || !MMU
910 bool 804 bool
911 default y 805 default y
912 806
913 config NEED_PER_CPU_EMBED_FIRST_CHUNK 807 config NEED_PER_CPU_EMBED_FIRST_CHUNK
914 bool 808 bool
915 809
916 config NEED_PER_CPU_PAGE_FIRST_CHUNK 810 config NEED_PER_CPU_PAGE_FIRST_CHUNK
917 bool 811 bool
918 812
919 config USE_PERCPU_NUMA_NODE_ID 813 config USE_PERCPU_NUMA_NODE_ID
920 bool 814 bool
921 815
922 config HAVE_SETUP_PER_CPU_AREA 816 config HAVE_SETUP_PER_CPU_AREA
923 bool 817 bool
924 818
>> 819 config FRONTSWAP
>> 820 bool
>> 821
925 config CMA 822 config CMA
926 bool "Contiguous Memory Allocator" 823 bool "Contiguous Memory Allocator"
927 depends on MMU 824 depends on MMU
928 select MIGRATION 825 select MIGRATION
929 select MEMORY_ISOLATION 826 select MEMORY_ISOLATION
930 help 827 help
931 This enables the Contiguous Memory A 828 This enables the Contiguous Memory Allocator which allows other
932 subsystems to allocate big physicall 829 subsystems to allocate big physically-contiguous blocks of memory.
933 CMA reserves a region of memory and 830 CMA reserves a region of memory and allows only movable pages to
934 be allocated from it. This way, the 831 be allocated from it. This way, the kernel can use the memory for
935 pagecache and when a subsystem reque 832 pagecache and when a subsystem requests for contiguous area, the
936 allocated pages are migrated away to 833 allocated pages are migrated away to serve the contiguous request.
937 834
938 If unsure, say "n". 835 If unsure, say "n".
939 836
>> 837 config CMA_DEBUG
>> 838 bool "CMA debug messages (DEVELOPMENT)"
>> 839 depends on DEBUG_KERNEL && CMA
>> 840 help
>> 841 Turns on debug messages in CMA. This produces KERN_DEBUG
>> 842 messages for every CMA call as well as various messages while
>> 843 processing calls such as dma_alloc_from_contiguous().
>> 844 This option does not affect warning and error messages.
>> 845
940 config CMA_DEBUGFS 846 config CMA_DEBUGFS
941 bool "CMA debugfs interface" 847 bool "CMA debugfs interface"
942 depends on CMA && DEBUG_FS 848 depends on CMA && DEBUG_FS
943 help 849 help
944 Turns on the DebugFS interface for C 850 Turns on the DebugFS interface for CMA.
945 851
946 config CMA_SYSFS 852 config CMA_SYSFS
947 bool "CMA information through sysfs in 853 bool "CMA information through sysfs interface"
948 depends on CMA && SYSFS 854 depends on CMA && SYSFS
949 help 855 help
950 This option exposes some sysfs attri 856 This option exposes some sysfs attributes to get information
951 from CMA. 857 from CMA.
952 858
953 config CMA_AREAS 859 config CMA_AREAS
954 int "Maximum count of the CMA areas" 860 int "Maximum count of the CMA areas"
955 depends on CMA 861 depends on CMA
956 default 20 if NUMA !! 862 default 19 if NUMA
957 default 8 !! 863 default 7
958 help 864 help
959 CMA allows to create CMA areas for p 865 CMA allows to create CMA areas for particular purpose, mainly,
960 used as device private area. This pa 866 used as device private area. This parameter sets the maximum
961 number of CMA area in the system. 867 number of CMA area in the system.
962 868
963 If unsure, leave the default value " !! 869 If unsure, leave the default value "7" in UMA and "19" in NUMA.
964 870
965 config MEM_SOFT_DIRTY 871 config MEM_SOFT_DIRTY
966 bool "Track memory changes" 872 bool "Track memory changes"
967 depends on CHECKPOINT_RESTORE && HAVE_ 873 depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
968 select PROC_PAGE_MONITOR 874 select PROC_PAGE_MONITOR
969 help 875 help
970 This option enables memory changes t 876 This option enables memory changes tracking by introducing a
971 soft-dirty bit on pte-s. This bit it 877 soft-dirty bit on pte-s. This bit it set when someone writes
972 into a page just as regular dirty bi 878 into a page just as regular dirty bit, but unlike the latter
973 it can be cleared by hands. 879 it can be cleared by hands.
974 880
975 See Documentation/admin-guide/mm/sof 881 See Documentation/admin-guide/mm/soft-dirty.rst for more details.
976 882
977 config GENERIC_EARLY_IOREMAP 883 config GENERIC_EARLY_IOREMAP
978 bool 884 bool
979 885
980 config STACK_MAX_DEFAULT_SIZE_MB 886 config STACK_MAX_DEFAULT_SIZE_MB
981 int "Default maximum user stack size f 887 int "Default maximum user stack size for 32-bit processes (MB)"
982 default 100 888 default 100
983 range 8 2048 889 range 8 2048
984 depends on STACK_GROWSUP && (!64BIT || 890 depends on STACK_GROWSUP && (!64BIT || COMPAT)
985 help 891 help
986 This is the maximum stack size in Me 892 This is the maximum stack size in Megabytes in the VM layout of 32-bit
987 user processes when the stack grows 893 user processes when the stack grows upwards (currently only on parisc
988 arch) when the RLIMIT_STACK hard lim 894 arch) when the RLIMIT_STACK hard limit is unlimited.
989 895
990 A sane initial value is 100 MB. 896 A sane initial value is 100 MB.
991 897
992 config DEFERRED_STRUCT_PAGE_INIT 898 config DEFERRED_STRUCT_PAGE_INIT
993 bool "Defer initialisation of struct p 899 bool "Defer initialisation of struct pages to kthreads"
994 depends on SPARSEMEM 900 depends on SPARSEMEM
995 depends on !NEED_PER_CPU_KM 901 depends on !NEED_PER_CPU_KM
996 depends on 64BIT 902 depends on 64BIT
997 depends on !KMSAN <<
998 select PADATA 903 select PADATA
999 help 904 help
1000 Ordinarily all struct pages are ini 905 Ordinarily all struct pages are initialised during early boot in a
1001 single thread. On very large machin 906 single thread. On very large machines this can take a considerable
1002 amount of time. If this option is s 907 amount of time. If this option is set, large machines will bring up
1003 a subset of memmap at boot and then 908 a subset of memmap at boot and then initialise the rest in parallel.
1004 This has a potential performance im 909 This has a potential performance impact on tasks running early in the
1005 lifetime of the system until these 910 lifetime of the system until these kthreads finish the
1006 initialisation. 911 initialisation.
1007 912
1008 config PAGE_IDLE_FLAG 913 config PAGE_IDLE_FLAG
1009 bool 914 bool
1010 select PAGE_EXTENSION if !64BIT 915 select PAGE_EXTENSION if !64BIT
1011 help 916 help
1012 This adds PG_idle and PG_young flag 917 This adds PG_idle and PG_young flags to 'struct page'. PTE Accessed
1013 bit writers can set the state of th 918 bit writers can set the state of the bit in the flags so that PTE
1014 Accessed bit readers may avoid dist 919 Accessed bit readers may avoid disturbance.
1015 920
1016 config IDLE_PAGE_TRACKING 921 config IDLE_PAGE_TRACKING
1017 bool "Enable idle page tracking" 922 bool "Enable idle page tracking"
1018 depends on SYSFS && MMU 923 depends on SYSFS && MMU
1019 select PAGE_IDLE_FLAG 924 select PAGE_IDLE_FLAG
1020 help 925 help
1021 This feature allows to estimate the 926 This feature allows to estimate the amount of user pages that have
1022 not been touched during a given per 927 not been touched during a given period of time. This information can
1023 be useful to tune memory cgroup lim 928 be useful to tune memory cgroup limits and/or for job placement
1024 within a compute cluster. 929 within a compute cluster.
1025 930
1026 See Documentation/admin-guide/mm/id 931 See Documentation/admin-guide/mm/idle_page_tracking.rst for
1027 more details. 932 more details.
1028 933
1029 # Architectures which implement cpu_dcache_is <<
1030 # whether the data caches are aliased (VIVT o <<
1031 # aliasing) need to select this. <<
1032 config ARCH_HAS_CPU_CACHE_ALIASING <<
1033 bool <<
1034 <<
1035 config ARCH_HAS_CACHE_LINE_SIZE 934 config ARCH_HAS_CACHE_LINE_SIZE
1036 bool 935 bool
1037 936
1038 config ARCH_HAS_CURRENT_STACK_POINTER 937 config ARCH_HAS_CURRENT_STACK_POINTER
1039 bool 938 bool
1040 help 939 help
1041 In support of HARDENED_USERCOPY per 940 In support of HARDENED_USERCOPY performing stack variable lifetime
1042 checking, an architecture-agnostic 941 checking, an architecture-agnostic way to find the stack pointer
1043 is needed. Once an architecture def 942 is needed. Once an architecture defines an unsigned long global
1044 register alias named "current_stack 943 register alias named "current_stack_pointer", this config can be
1045 selected. 944 selected.
1046 945
1047 config ARCH_HAS_PTE_DEVMAP 946 config ARCH_HAS_PTE_DEVMAP
1048 bool 947 bool
1049 948
1050 config ARCH_HAS_ZONE_DMA_SET 949 config ARCH_HAS_ZONE_DMA_SET
1051 bool 950 bool
1052 951
1053 config ZONE_DMA 952 config ZONE_DMA
1054 bool "Support DMA zone" if ARCH_HAS_Z 953 bool "Support DMA zone" if ARCH_HAS_ZONE_DMA_SET
1055 default y if ARM64 || X86 954 default y if ARM64 || X86
1056 955
1057 config ZONE_DMA32 956 config ZONE_DMA32
1058 bool "Support DMA32 zone" if ARCH_HAS 957 bool "Support DMA32 zone" if ARCH_HAS_ZONE_DMA_SET
1059 depends on !X86_32 958 depends on !X86_32
1060 default y if ARM64 959 default y if ARM64
1061 960
1062 config ZONE_DEVICE 961 config ZONE_DEVICE
1063 bool "Device memory (pmem, HMM, etc.. 962 bool "Device memory (pmem, HMM, etc...) hotplug support"
1064 depends on MEMORY_HOTPLUG 963 depends on MEMORY_HOTPLUG
1065 depends on MEMORY_HOTREMOVE 964 depends on MEMORY_HOTREMOVE
1066 depends on SPARSEMEM_VMEMMAP 965 depends on SPARSEMEM_VMEMMAP
1067 depends on ARCH_HAS_PTE_DEVMAP 966 depends on ARCH_HAS_PTE_DEVMAP
1068 select XARRAY_MULTI 967 select XARRAY_MULTI
1069 968
1070 help 969 help
1071 Device memory hotplug support allow 970 Device memory hotplug support allows for establishing pmem,
1072 or other device driver discovered m 971 or other device driver discovered memory regions, in the
1073 memmap. This allows pfn_to_page() l 972 memmap. This allows pfn_to_page() lookups of otherwise
1074 "device-physical" addresses which i 973 "device-physical" addresses which is needed for using a DAX
1075 mapping in an O_DIRECT operation, a 974 mapping in an O_DIRECT operation, among other things.
1076 975
1077 If FS_DAX is enabled, then say Y. 976 If FS_DAX is enabled, then say Y.
1078 977
1079 # 978 #
1080 # Helpers to mirror range of the CPU page tab 979 # Helpers to mirror range of the CPU page tables of a process into device page
1081 # tables. 980 # tables.
1082 # 981 #
1083 config HMM_MIRROR 982 config HMM_MIRROR
1084 bool 983 bool
1085 depends on MMU 984 depends on MMU
1086 985
1087 config GET_FREE_REGION 986 config GET_FREE_REGION
>> 987 depends on SPARSEMEM
1088 bool 988 bool
1089 989
1090 config DEVICE_PRIVATE 990 config DEVICE_PRIVATE
1091 bool "Unaddressable device memory (GP 991 bool "Unaddressable device memory (GPU memory, ...)"
1092 depends on ZONE_DEVICE 992 depends on ZONE_DEVICE
1093 select GET_FREE_REGION 993 select GET_FREE_REGION
1094 994
1095 help 995 help
1096 Allows creation of struct pages to 996 Allows creation of struct pages to represent unaddressable device
1097 memory; i.e., memory that is only a 997 memory; i.e., memory that is only accessible from the device (or
1098 group of devices). You likely also 998 group of devices). You likely also want to select HMM_MIRROR.
1099 999
1100 config VMAP_PFN 1000 config VMAP_PFN
1101 bool 1001 bool
1102 1002
1103 config ARCH_USES_HIGH_VMA_FLAGS 1003 config ARCH_USES_HIGH_VMA_FLAGS
1104 bool 1004 bool
1105 config ARCH_HAS_PKEYS 1005 config ARCH_HAS_PKEYS
1106 bool 1006 bool
1107 1007
1108 config ARCH_USES_PG_ARCH_2 <<
1109 bool <<
1110 config ARCH_USES_PG_ARCH_3 <<
1111 bool <<
1112 <<
1113 config VM_EVENT_COUNTERS 1008 config VM_EVENT_COUNTERS
1114 default y 1009 default y
1115 bool "Enable VM event counters for /p 1010 bool "Enable VM event counters for /proc/vmstat" if EXPERT
1116 help 1011 help
1117 VM event counters are needed for ev 1012 VM event counters are needed for event counts to be shown.
1118 This option allows the disabling of 1013 This option allows the disabling of the VM event counters
1119 on EXPERT systems. /proc/vmstat wi 1014 on EXPERT systems. /proc/vmstat will only show page counts
1120 if VM event counters are disabled. 1015 if VM event counters are disabled.
1121 1016
1122 config PERCPU_STATS 1017 config PERCPU_STATS
1123 bool "Collect percpu memory statistic 1018 bool "Collect percpu memory statistics"
1124 help 1019 help
1125 This feature collects and exposes s 1020 This feature collects and exposes statistics via debugfs. The
1126 information includes global and per 1021 information includes global and per chunk statistics, which can
1127 be used to help understand percpu m 1022 be used to help understand percpu memory usage.
1128 1023
1129 config GUP_TEST 1024 config GUP_TEST
1130 bool "Enable infrastructure for get_u 1025 bool "Enable infrastructure for get_user_pages()-related unit tests"
1131 depends on DEBUG_FS 1026 depends on DEBUG_FS
1132 help 1027 help
1133 Provides /sys/kernel/debug/gup_test 1028 Provides /sys/kernel/debug/gup_test, which in turn provides a way
1134 to make ioctl calls that can launch 1029 to make ioctl calls that can launch kernel-based unit tests for
1135 the get_user_pages*() and pin_user_ 1030 the get_user_pages*() and pin_user_pages*() family of API calls.
1136 1031
1137 These tests include benchmark testi 1032 These tests include benchmark testing of the _fast variants of
1138 get_user_pages*() and pin_user_page 1033 get_user_pages*() and pin_user_pages*(), as well as smoke tests of
1139 the non-_fast variants. 1034 the non-_fast variants.
1140 1035
1141 There is also a sub-test that allow 1036 There is also a sub-test that allows running dump_page() on any
1142 of up to eight pages (selected by c 1037 of up to eight pages (selected by command line args) within the
1143 range of user-space addresses. Thes 1038 range of user-space addresses. These pages are either pinned via
1144 pin_user_pages*(), or pinned via ge 1039 pin_user_pages*(), or pinned via get_user_pages*(), as specified
1145 by other command line arguments. 1040 by other command line arguments.
1146 1041
1147 See tools/testing/selftests/mm/gup_ !! 1042 See tools/testing/selftests/vm/gup_test.c
1148 1043
1149 comment "GUP_TEST needs to have DEBUG_FS enab 1044 comment "GUP_TEST needs to have DEBUG_FS enabled"
1150 depends on !GUP_TEST && !DEBUG_FS 1045 depends on !GUP_TEST && !DEBUG_FS
1151 1046
1152 config GUP_GET_PXX_LOW_HIGH !! 1047 config GUP_GET_PTE_LOW_HIGH
1153 bool 1048 bool
1154 1049
1155 config DMAPOOL_TEST <<
1156 tristate "Enable a module to run time <<
1157 depends on HAS_DMA <<
1158 help <<
1159 Provides a test module that will al <<
1160 various sizes and report how long i <<
1161 provide a consistent way to measure <<
1162 dma_pool_alloc/free routines affect <<
1163 <<
1164 config ARCH_HAS_PTE_SPECIAL 1050 config ARCH_HAS_PTE_SPECIAL
1165 bool 1051 bool
1166 1052
>> 1053 #
>> 1054 # Some architectures require a special hugepage directory format that is
>> 1055 # required to support multiple hugepage sizes. For example a4fe3ce76
>> 1056 # "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
>> 1057 # introduced it on powerpc. This allows for a more flexible hugepage
>> 1058 # pagetable layouts.
>> 1059 #
>> 1060 config ARCH_HAS_HUGEPD
>> 1061 bool
>> 1062
1167 config MAPPING_DIRTY_HELPERS 1063 config MAPPING_DIRTY_HELPERS
1168 bool 1064 bool
1169 1065
1170 config KMAP_LOCAL 1066 config KMAP_LOCAL
1171 bool 1067 bool
1172 1068
1173 config KMAP_LOCAL_NON_LINEAR_PTE_ARRAY 1069 config KMAP_LOCAL_NON_LINEAR_PTE_ARRAY
1174 bool 1070 bool
1175 1071
1176 # struct io_mapping based helper. Selected b 1072 # struct io_mapping based helper. Selected by drivers that need them
1177 config IO_MAPPING 1073 config IO_MAPPING
1178 bool 1074 bool
1179 1075
1180 config MEMFD_CREATE <<
1181 bool "Enable memfd_create() system ca <<
1182 <<
1183 config SECRETMEM 1076 config SECRETMEM
1184 default y !! 1077 def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED
1185 bool "Enable memfd_secret() system ca <<
1186 depends on ARCH_HAS_SET_DIRECT_MAP <<
1187 help <<
1188 Enable the memfd_secret() system ca <<
1189 memory areas visible only in the co <<
1190 not mapped to other processes and o <<
1191 1078
1192 config ANON_VMA_NAME 1079 config ANON_VMA_NAME
1193 bool "Anonymous VMA name support" 1080 bool "Anonymous VMA name support"
1194 depends on PROC_FS && ADVISE_SYSCALLS 1081 depends on PROC_FS && ADVISE_SYSCALLS && MMU
1195 1082
1196 help 1083 help
1197 Allow naming anonymous virtual memo 1084 Allow naming anonymous virtual memory areas.
1198 1085
1199 This feature allows assigning names 1086 This feature allows assigning names to virtual memory areas. Assigned
1200 names can be later retrieved from / 1087 names can be later retrieved from /proc/pid/maps and /proc/pid/smaps
1201 and help identifying individual ano 1088 and help identifying individual anonymous memory areas.
1202 Assigning a name to anonymous virtu 1089 Assigning a name to anonymous virtual memory area might prevent that
1203 area from being merged with adjacen 1090 area from being merged with adjacent virtual memory areas due to the
1204 difference in their name. 1091 difference in their name.
1205 1092
>> 1093 config USERFAULTFD
>> 1094 bool "Enable userfaultfd() system call"
>> 1095 depends on MMU
>> 1096 help
>> 1097 Enable the userfaultfd() system call that allows to intercept and
>> 1098 handle page faults in userland.
>> 1099
1206 config HAVE_ARCH_USERFAULTFD_WP 1100 config HAVE_ARCH_USERFAULTFD_WP
1207 bool 1101 bool
1208 help 1102 help
1209 Arch has userfaultfd write protecti 1103 Arch has userfaultfd write protection support
1210 1104
1211 config HAVE_ARCH_USERFAULTFD_MINOR 1105 config HAVE_ARCH_USERFAULTFD_MINOR
1212 bool 1106 bool
1213 help 1107 help
1214 Arch has userfaultfd minor fault su 1108 Arch has userfaultfd minor fault support
1215 1109
1216 menuconfig USERFAULTFD !! 1110 config PTE_MARKER
1217 bool "Enable userfaultfd() system cal !! 1111 bool
1218 depends on MMU !! 1112
1219 help 1113 help
1220 Enable the userfaultfd() system cal !! 1114 Allows to create marker PTEs for file-backed memory.
1221 handle page faults in userland. <<
1222 1115
1223 if USERFAULTFD <<
1224 config PTE_MARKER_UFFD_WP 1116 config PTE_MARKER_UFFD_WP
1225 bool "Userfaultfd write protection su 1117 bool "Userfaultfd write protection support for shmem/hugetlbfs"
1226 default y 1118 default y
1227 depends on HAVE_ARCH_USERFAULTFD_WP 1119 depends on HAVE_ARCH_USERFAULTFD_WP
>> 1120 select PTE_MARKER
1228 1121
1229 help 1122 help
1230 Allows to create marker PTEs for us 1123 Allows to create marker PTEs for userfaultfd write protection
1231 purposes. It is required to enable 1124 purposes. It is required to enable userfaultfd write protection on
1232 file-backed memory types like shmem 1125 file-backed memory types like shmem and hugetlbfs.
1233 endif # USERFAULTFD <<
1234 <<
1235 # multi-gen LRU { <<
1236 config LRU_GEN <<
1237 bool "Multi-Gen LRU" <<
1238 depends on MMU <<
1239 # make sure folio->flags has enough s <<
1240 depends on 64BIT || !SPARSEMEM || SPA <<
1241 help <<
1242 A high performance LRU implementati <<
1243 Documentation/admin-guide/mm/multig <<
1244 <<
1245 config LRU_GEN_ENABLED <<
1246 bool "Enable by default" <<
1247 depends on LRU_GEN <<
1248 help <<
1249 This option enables the multi-gen L <<
1250 <<
1251 config LRU_GEN_STATS <<
1252 bool "Full stats for debugging" <<
1253 depends on LRU_GEN <<
1254 help <<
1255 Do not enable this option unless yo <<
1256 from evicted generations for debugg <<
1257 <<
1258 This option has a per-memcg and per <<
1259 <<
1260 config LRU_GEN_WALKS_MMU <<
1261 def_bool y <<
1262 depends on LRU_GEN && ARCH_HAS_HW_PTE <<
1263 # } <<
1264 <<
1265 config ARCH_SUPPORTS_PER_VMA_LOCK <<
1266 def_bool n <<
1267 <<
1268 config PER_VMA_LOCK <<
1269 def_bool y <<
1270 depends on ARCH_SUPPORTS_PER_VMA_LOCK <<
1271 help <<
1272 Allow per-vma locking during page f <<
1273 <<
1274 This feature allows locking each vi <<
1275 handling page faults instead of tak <<
1276 <<
1277 config LOCK_MM_AND_FIND_VMA <<
1278 bool <<
1279 depends on !STACK_GROWSUP <<
1280 <<
1281 config IOMMU_MM_DATA <<
1282 bool <<
1283 <<
1284 config EXECMEM <<
1285 bool <<
1286 <<
1287 config NUMA_MEMBLKS <<
1288 bool <<
1289 <<
1290 config NUMA_EMU <<
1291 bool "NUMA emulation" <<
1292 depends on NUMA_MEMBLKS <<
1293 help <<
1294 Enable NUMA emulation. A flat machi <<
1295 into virtual nodes when booted with <<
1296 number of nodes. This is only usefu <<
1297 1126
1298 source "mm/damon/Kconfig" 1127 source "mm/damon/Kconfig"
1299 1128
1300 endmenu 1129 endmenu
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