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