Lines Matching +full:default +full:- +full:on
1 # SPDX-License-Identifier: GPL-2.0-only
14 depends on MMU && BLOCK && !ARCH_NO_SWAP
15 default y
24 depends on SWAP
30 compress them into a dynamically allocated RAM-based memory pool.
31 This can result in a significant I/O reduction on swap device and,
36 bool "Enable the compressed cache for swap pages by default"
37 depends on ZSWAP
46 bool "Shrink the zswap pool on memory pressure"
47 depends on ZSWAP
48 default n
52 written back to the backing swap device) on memory pressure.
60 prompt "Default compressor"
61 depends on ZSWAP
62 default ZSWAP_COMPRESSOR_DEFAULT_LZO
64 Selects the default compression algorithm for the compressed cache
81 Use the Deflate algorithm as the default compression algorithm.
87 Use the LZO algorithm as the default compression algorithm.
93 Use the 842 algorithm as the default compression algorithm.
99 Use the LZ4 algorithm as the default compression algorithm.
105 Use the LZ4HC algorithm as the default compression algorithm.
111 Use the zstd algorithm as the default compression algorithm.
116 depends on ZSWAP
117 default "deflate" if ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
118 default "lzo" if ZSWAP_COMPRESSOR_DEFAULT_LZO
119 default "842" if ZSWAP_COMPRESSOR_DEFAULT_842
120 default "lz4" if ZSWAP_COMPRESSOR_DEFAULT_LZ4
121 default "lz4hc" if ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
122 default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD
123 default ""
131 depends on ZSMALLOC
145 int "Maximum number of physical pages per-zspage"
146 default 8
149 This option sets the upper limit on the number of physical pages
174 depends on !SLUB_TINY && !TINY_RCU
178 depends on EXPERT && !COMPILE_TEST
191 default y
200 merging at runtime, "slab_nomerge" can be passed on the kernel
205 depends on !SLUB_TINY
207 Randomizes the freelist order used on creating new pages. This
213 depends on !SLUB_TINY
222 depends on !SLUB_TINY
223 default SLAB_FREELIST_HARDENED
225 Kernel heap attacks frequently depend on being able to create
226 specifically-sized allocations with user-controlled contents
230 user-controlled allocations. This may very slightly increase
232 of extra pages since the bulk of user-controlled allocations
233 are relatively long-lived.
238 default n
240 depends on SYSFS && !SLUB_TINY
248 Try running: slabinfo -DA
251 default y
252 depends on SMP && !SLUB_TINY
257 in the latency of the free. On overflow these caches will be cleared
262 default n
263 depends on !SLUB_TINY
268 on code address, which makes the attackers more difficult to spray
269 vulnerable memory objects on the heap for the purpose of exploiting
282 default SLAB_FREELIST_RANDOM && ACPI_NUMA
285 utilization of a direct-mapped memory-side-cache. See section
288 the presence of a memory-side-cache. There are also incidental
291 default granularity of shuffling on the MAX_PAGE_ORDER i.e, 10th
292 order of pages is selected based on cache utilization benefits
293 on x86.
296 negatively impact workloads on platforms without a cache. For
297 this reason, by default, the randomization is not enabled even
305 default y
309 This option changes the bootup default to heap randomization
313 On non-ancient distros (post-2000 ones) N is usually a safe choice.
317 depends on EXPERT && !MMU
318 default n
328 ELF-FDPIC binfmt's brk and stack allocator.
331 enabled on embedded devices where you control what is run in
332 userspace. Since that isn't generally a problem on no-MMU systems,
335 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
339 depends on ARCH_SELECT_MEMORY_MODEL
343 depends on SELECT_MEMORY_MODEL
344 default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
345 default FLATMEM_MANUAL
354 depends on !ARCH_SPARSEMEM_ENABLE || ARCH_FLATMEM_ENABLE
356 This option is best suited for non-NUMA systems with
369 depends on ARCH_SPARSEMEM_ENABLE
372 memory hot-plug systems. This is normal.
376 hot-plug and hot-remove.
384 depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL
388 depends on !SPARSEMEM || FLATMEM_MANUAL
391 # SPARSEMEM_EXTREME (which is the default) does some bootmem
393 # be done on your architecture, select this option. However,
410 depends on SPARSEMEM && !SPARSEMEM_STATIC
417 depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
442 depends on MMU
455 # Keep arch NUMA mapping infrastructure post-init.
467 depends on !DEVMEM || STRICT_DEVMEM
470 # Only be set on architectures that have completely implemented memory hotplug
486 depends on SPARSEMEM
487 depends on ARCH_ENABLE_MEMORY_HOTPLUG
488 depends on 64BIT
494 prompt "Memory Hotplug Default Online Type"
495 default MHP_DEFAULT_ONLINE_TYPE_OFFLINE
497 Default memory type for hotplugged memory.
499 This option sets the default policy setting for memory hotplug
504 The default is 'offline'.
513 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
518 Hotplugged memory will not be onlined by default.
546 sufficient kernel-capable memory (ZONE_NORMAL) must be
554 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
555 depends on MIGRATION
559 depends on MEMORY_HOTPLUG && SPARSEMEM_VMEMMAP
560 depends on ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
567 # Heavily threaded applications may benefit from splitting the mm-wide
568 # page_table_lock, so that faults on different parts of the user address
570 # Default to 4 for wider testing, though 8 might be more appropriate.
571 # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
572 # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
574 # a per-page lock leads to problems when multiple tables need to be locked
580 depends on MMU
581 depends on SMP
582 depends on NR_CPUS >= 4
583 depends on !ARM || CPU_CACHE_VIPT
584 depends on !PARISC || PA20
585 depends on !SPARC32
592 depends on SPLIT_PTE_PTLOCKS && ARCH_ENABLE_SPLIT_PMD_PTLOCK
603 default y
604 depends on COMPACTION && MEMORY_BALLOON
618 default y
620 depends on MMU
624 reliably. The page allocator relies on compaction heavily and
629 linux-mm@kvack.org.
633 depends on COMPACTION
634 default 0 if PREEMPT_RT
635 default 1
652 default y
653 depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
657 two situations. The first is on NUMA systems to put pages nearer
676 on a platform.
685 int "Maximum scale factor of PCP (Per-CPU pageset) batch allocate/free"
686 default 5
689 In page allocator, PCP (Per-CPU pageset) is refilled and drained in
700 default y
701 depends on BLOCK && MMU && HIGHMEM
704 memory available to the CPU. Enabled by default when HIGHMEM is
713 depends on MMU
728 depends on MMU
729 default 4096
737 On arm and other archs it should not be higher than 32768.
749 depends on MMU
750 depends on ARCH_SUPPORTS_MEMORY_FAILURE
754 Enables code to recover from some memory failures on systems
761 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
765 int "Turn on mmap() excess space trimming before booting"
766 depends on !MMU
767 default 1
770 of memory on which to store mappings, but it can only ask the system
771 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
780 long-term mappings means that the space is wasted.
787 This option specifies the initial value of this option. The default
790 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
800 depends on TRANSPARENT_HUGEPAGE
819 depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE && !PREEMPT_RT
831 If memory constrained on embedded, you may want to say N.
837 depends on TRANSPARENT_HUGEPAGE
838 default TRANSPARENT_HUGEPAGE_ALWAYS
861 Disable Transparent Hugepage by default. It can still be
867 depends on TRANSPARENT_HUGEPAGE && ARCH_WANTS_THP_SWAP && SWAP && 64BIT
876 bool "Read-only THP for filesystems (EXPERIMENTAL)"
877 depends on TRANSPARENT_HUGEPAGE
880 Allow khugepaged to put read-only file-backed pages in THP.
887 bool "No per-page mapcount (EXPERIMENTAL)"
889 Do not maintain per-page mapcounts for pages part of larger
892 When this config option is enabled, some interfaces that relied on
893 this information will rely on less-precise per-allocation information
894 instead: for example, using the average per-page mapcount in such
895 a large allocation instead of the per-page mapcount.
914 depends on TRANSPARENT_HUGEPAGE
918 depends on ARCH_SUPPORTS_HUGE_PFNMAP && HAVE_ARCH_TRANSPARENT_HUGEPAGE
922 depends on ARCH_SUPPORTS_HUGE_PFNMAP && HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
935 depends on !SMP || !MMU
937 default y
953 depends on MMU
958 subsystems to allocate big physically-contiguous blocks of memory.
968 depends on CMA && DEBUG_FS
970 Turns on the DebugFS interface for CMA.
974 depends on CMA && SYSFS
981 depends on CMA
982 default 20 if NUMA
983 default 8
989 If unsure, leave the default value "8" in UMA and "20" in NUMA.
1000 # the default page block order is MAX_PAGE_ORDER (10) as per
1006 default 10 if ARCH_FORCE_MAX_ORDER = 0
1008 default ARCH_FORCE_MAX_ORDER if ARCH_FORCE_MAX_ORDER != 0
1015 This config adds a new upper limit of default page block
1018 (see include/linux/pageblock-flags.h for details).
1028 depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
1032 soft-dirty bit on pte-s. This bit it set when someone writes
1036 See Documentation/admin-guide/mm/soft-dirty.rst for more details.
1042 int "Default maximum user stack size for 32-bit processes (MB)"
1043 default 100
1045 depends on STACK_GROWSUP && (!64BIT || COMPAT)
1047 This is the maximum stack size in Megabytes in the VM layout of 32-bit
1048 user processes when the stack grows upwards (currently only on parisc
1055 depends on SPARSEMEM
1056 depends on !NEED_PER_CPU_KM
1057 depends on 64BIT
1058 depends on !KMSAN
1062 single thread. On very large machines this can take a considerable
1065 This has a potential performance impact on tasks running early in the
1079 depends on SYSFS && MMU
1087 See Documentation/admin-guide/mm/idle_page_tracking.rst for
1103 checking, an architecture-agnostic way to find the stack pointer
1113 default y if ARM64 || X86
1117 depends on !X86_32
1118 default y if ARM64
1122 depends on MEMORY_HOTPLUG
1123 depends on MEMORY_HOTREMOVE
1124 depends on SPARSEMEM_VMEMMAP
1131 "device-physical" addresses which is needed for using a DAX
1142 depends on MMU
1149 depends on ZONE_DEVICE
1171 default y
1176 on EXPERT systems. /proc/vmstat will only show page counts
1187 bool "Enable infrastructure for get_user_pages()-related unit tests"
1188 depends on DEBUG_FS
1191 to make ioctl calls that can launch kernel-based unit tests for
1196 the non-_fast variants.
1198 There is also a sub-test that allows running dump_page() on any
1200 range of user-space addresses. These pages are either pinned via
1207 depends on !GUP_TEST && !DEBUG_FS
1213 tristate "Enable a module to run time tests on dma_pool"
1214 depends on HAS_DMA
1237 default y
1239 depends on ARCH_HAS_SET_DIRECT_MAP
1247 depends on PROC_FS && ADVISE_SYSCALLS && MMU
1271 depends on MMU
1279 default y
1280 depends on HAVE_ARCH_USERFAULTFD_WP
1284 purposes. It is required to enable userfaultfd write protection on
1285 file-backed memory types like shmem and hugetlbfs.
1288 # multi-gen LRU {
1290 bool "Multi-Gen LRU"
1291 depends on MMU
1292 # make sure folio->flags has enough spare bits
1293 depends on 64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP
1296 Documentation/admin-guide/mm/multigen_lru.rst for details.
1299 bool "Enable by default"
1300 depends on LRU_GEN
1302 This option enables the multi-gen LRU by default.
1306 depends on LRU_GEN
1311 This option has a per-memcg and per-node memory overhead.
1315 depends on LRU_GEN && ARCH_HAS_HW_PTE_YOUNG
1323 depends on ARCH_SUPPORTS_PER_VMA_LOCK && MMU && SMP
1325 Allow per-vma locking during page fault handling.
1332 depends on !STACK_GROWSUP
1345 depends on NUMA_MEMBLKS
1346 depends on X86 || GENERIC_ARCH_NUMA
1356 stacks (eg, x86 CET, arm64 GCS or RISC-V Zicfiss).
1363 default y
1364 depends on ARCH_SUPPORTS_PT_RECLAIM && MMU && SMP