config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
- depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
+ depends on HOTPLUG && !(HIBERNATION && !S390) && ARCH_ENABLE_MEMORY_HOTPLUG
depends on (IA64 || X86 || PPC64 || SUPERH || S390)
comment "Memory hotplug is currently incompatible with Software Suspend"
- depends on SPARSEMEM && HOTPLUG && HIBERNATION
+ depends on SPARSEMEM && HOTPLUG && HIBERNATION && !S390
config MEMORY_HOTPLUG_SPARSE
def_bool y
#
config PAGEFLAGS_EXTENDED
def_bool y
- depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM
+ depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
# Heavily threaded applications may benefit from splitting the mm-wide
# page_table_lock, so that faults on different parts of the user address
def_bool y
depends on !ARCH_NO_VIRT_TO_BUS
-config UNEVICTABLE_LRU
- bool "Add LRU list to track non-evictable pages"
- default y
- depends on MMU
- help
- Keeps unevictable pages off of the active and inactive pageout
- lists, so kswapd will not waste CPU time or have its balancing
- algorithms thrown off by scanning these pages. Selecting this
- will use one page flag and increase the code size a little,
- say Y unless you know what you are doing.
-
config HAVE_MLOCK
bool
default y if MMU=y
config HAVE_MLOCKED_PAGE_BIT
bool
- default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
+ default y if HAVE_MLOCK=y
config MMU_NOTIFIER
bool
+
+config DEFAULT_MMAP_MIN_ADDR
+ int "Low address space to protect from user allocation"
+ default 4096
+ help
+ This is the portion of low virtual memory which should be protected
+ from userspace allocation. Keeping a user from writing to low pages
+ can help reduce the impact of kernel NULL pointer bugs.
+
+ For most ia64, ppc64 and x86 users with lots of address space
+ a value of 65536 is reasonable and should cause no problems.
+ On arm and other archs it should not be higher than 32768.
+ Programs which use vm86 functionality or have some need to map
+ this low address space will need CAP_SYS_RAWIO or disable this
+ protection by setting the value to 0.
+
+ This value can be changed after boot using the
+ /proc/sys/vm/mmap_min_addr tunable.
+
+
+config NOMMU_INITIAL_TRIM_EXCESS
+ int "Turn on mmap() excess space trimming before booting"
+ depends on !MMU
+ default 1
+ help
+ The NOMMU mmap() frequently needs to allocate large contiguous chunks
+ of memory on which to store mappings, but it can only ask the system
+ allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
+ more than it requires. To deal with this, mmap() is able to trim off
+ the excess and return it to the allocator.
+
+ If trimming is enabled, the excess is trimmed off and returned to the
+ system allocator, which can cause extra fragmentation, particularly
+ if there are a lot of transient processes.
+
+ If trimming is disabled, the excess is kept, but not used, which for
+ long-term mappings means that the space is wasted.
+
+ Trimming can be dynamically controlled through a sysctl option
+ (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
+ excess pages there must be before trimming should occur, or zero if
+ no trimming is to occur.
+
+ This option specifies the initial value of this option. The default
+ of 1 says that all excess pages should be trimmed.
+
+ See Documentation/nommu-mmap.txt for more information.