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author | Vlastimil Babka <vbabka@suse.cz> | 2022-05-25 13:25:59 +0200 |
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committer | akpm <akpm@linux-foundation.org> | 2022-05-27 09:33:47 -0700 |
commit | 0710d0122abc93adcb9a70a78f1625c491f6ad91 (patch) | |
tree | 1ee56844a3b8b90d8b0411d6c56440d3e5b62bf4 /mm | |
parent | fbf4df0699926cf620b2f722ddc213826e248962 (diff) | |
download | linux-stable-0710d0122abc93adcb9a70a78f1625c491f6ad91.tar.gz linux-stable-0710d0122abc93adcb9a70a78f1625c491f6ad91.tar.bz2 linux-stable-0710d0122abc93adcb9a70a78f1625c491f6ad91.zip |
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')
-rw-r--r-- | mm/Kconfig | 56 | ||||
-rw-r--r-- | mm/Kconfig.debug | 31 |
2 files changed, 87 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 diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 5bd5bb097252..197eb287bf82 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -45,6 +45,37 @@ config DEBUG_PAGEALLOC_ENABLE_DEFAULT Enable debug page memory allocations by default? This value can be overridden by debug_pagealloc=off|on. +config DEBUG_SLAB + bool "Debug slab memory allocations" + depends on DEBUG_KERNEL && SLAB + help + Say Y here to have the kernel do limited verification on memory + allocation as well as poisoning memory on free to catch use of freed + memory. This can make kmalloc/kfree-intensive workloads much slower. + +config SLUB_DEBUG + default y + bool "Enable SLUB debugging support" if EXPERT + depends on SLUB && SYSFS + help + SLUB has extensive debug support features. Disabling these can + result in significant savings in code size. This also disables + SLUB sysfs support. /sys/slab will not exist and there will be + no support for cache validation etc. + +config SLUB_DEBUG_ON + bool "SLUB debugging on by default" + depends on SLUB && SLUB_DEBUG + default n + help + Boot with debugging on by default. SLUB boots by default with + the runtime debug capabilities switched off. Enabling this is + equivalent to specifying the "slub_debug" parameter on boot. + There is no support for more fine grained debug control like + possible with slub_debug=xxx. SLUB debugging may be switched + off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying + "slub_debug=-". + config PAGE_OWNER bool "Track page owner" depends on DEBUG_KERNEL && STACKTRACE_SUPPORT |