From 0710d0122abc93adcb9a70a78f1625c491f6ad91 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Wed, 25 May 2022 13:25:59 +0200 Subject: [PATCH] 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 Acked-by: Johannes Weiner Signed-off-by: Andrew Morton --- init/Kconfig | 53 ---------------------------------------------------- lib/Kconfig.debug | 34 --------------------------------- mm/Kconfig | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/Kconfig.debug | 31 ++++++++++++++++++++++++++++++ 4 files changed, 87 insertions(+), 87 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 1d2ecd2..0cff027 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1828,59 +1828,6 @@ config DEBUG_PERF_USE_VMALLOC endmenu -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 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 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 SYSTEM_DATA_VERIFICATION def_bool n select SYSTEM_TRUSTED_KEYRING diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 075cd25..25763dc 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -698,40 +698,6 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT help Debug objects boot parameter default value -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_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 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 HAVE_DEBUG_KMEMLEAK bool diff --git a/mm/Kconfig b/mm/Kconfig index 905c205..169e641 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 5bd5bb0..197eb28 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 -- 2.7.4