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author | Vlastimil Babka <vbabka@suse.cz> | 2022-05-25 13:25:59 +0200 |
---|---|---|
committer | akpm <akpm@linux-foundation.org> | 2022-05-27 09:33:47 -0700 |
commit | 0710d0122abc93adcb9a70a78f1625c491f6ad91 (patch) | |
tree | 1ee56844a3b8b90d8b0411d6c56440d3e5b62bf4 /mm/Kconfig | |
parent | fbf4df0699926cf620b2f722ddc213826e248962 (diff) | |
download | linux-next-0710d0122abc93adcb9a70a78f1625c491f6ad91.tar.gz |
mm: Kconfig: reorganize misplaced mm options
After commits 7b42f1041c98 ("mm: Kconfig: move swap and slab config
options to the MM section") and 519bcb797907 ("mm: Kconfig: group swap,
slab, hotplug and thp options into submenus") we now have nicely organized
mm related config options. I have noticed some that were still misplaced,
so this moves them from various places into the new structure:
VM_EVENT_COUNTERS, COMPAT_BRK, MMAP_ALLOW_UNINITIALIZED to mm/Kconfig and
general MM section.
SLUB_STATS to mm/Kconfig and the slab submenu.
DEBUG_SLAB, SLUB_DEBUG, SLUB_DEBUG_ON to mm/Kconfig.debug and the Kernel
hacking / Memory Debugging submenu.
Link: https://lkml.kernel.org/r/20220525112559.1139-1-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/Kconfig')
-rw-r--r-- | mm/Kconfig | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 905c205e14f3..169e64192e48 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -270,6 +270,19 @@ config SLAB_FREELIST_HARDENED sanity-checking than others. This option is most effective with CONFIG_SLUB. +config SLUB_STATS + default n + bool "Enable SLUB performance statistics" + depends on SLUB && SYSFS + help + SLUB statistics are useful to debug SLUBs allocation behavior in + order find ways to optimize the allocator. This should never be + enabled for production use since keeping statistics slows down + the allocator by a few percentage points. The slabinfo command + supports the determination of the most active slabs to figure + out which slabs are relevant to a particular load. + Try running: slabinfo -DA + config SLUB_CPU_PARTIAL default y depends on SLUB && SMP @@ -307,6 +320,40 @@ config SHUFFLE_PAGE_ALLOCATOR Say Y if unsure. +config COMPAT_BRK + bool "Disable heap randomization" + default y + help + Randomizing heap placement makes heap exploits harder, but it + also breaks ancient binaries (including anything libc5 based). + This option changes the bootup default to heap randomization + disabled, and can be overridden at runtime by setting + /proc/sys/kernel/randomize_va_space to 2. + + On non-ancient distros (post-2000 ones) N is usually a safe choice. + +config MMAP_ALLOW_UNINITIALIZED + bool "Allow mmapped anonymous memory to be uninitialized" + depends on EXPERT && !MMU + default n + help + Normally, and according to the Linux spec, anonymous memory obtained + from mmap() has its contents cleared before it is passed to + userspace. Enabling this config option allows you to request that + mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus + providing a huge performance boost. If this option is not enabled, + then the flag will be ignored. + + This is taken advantage of by uClibc's malloc(), and also by + ELF-FDPIC binfmt's brk and stack allocator. + + Because of the obvious security issues, this option should only be + enabled on embedded devices where you control what is run in + userspace. Since that isn't generally a problem on no-MMU systems, + it is normally safe to say Y here. + + See Documentation/admin-guide/mm/nommu-mmap.rst for more information. + config SELECT_MEMORY_MODEL def_bool y depends on ARCH_SELECT_MEMORY_MODEL @@ -964,6 +1011,15 @@ config ARCH_USES_HIGH_VMA_FLAGS config ARCH_HAS_PKEYS bool +config VM_EVENT_COUNTERS + default y + bool "Enable VM event counters for /proc/vmstat" if EXPERT + help + VM event counters are needed for event counts to be shown. + This option allows the disabling of the VM event counters + on EXPERT systems. /proc/vmstat will only show page counts + if VM event counters are disabled. + config PERCPU_STATS bool "Collect percpu memory statistics" help |