in their physical address spaces, and this option provides
more efficient handling of these holes. However, the vast
majority of hardware has quite flat address spaces, and
- can have degraded performance from extra overhead that
+ can have degraded performance from the extra overhead that
this option imposes.
Many NUMA configurations will have this as the only option.
# with gcc 3.4 and later.
#
config SPARSEMEM_STATIC
- def_bool n
+ bool
#
# Architecture platforms which require a two level mem_section in SPARSEMEM
def_bool y
depends on SPARSEMEM && !SPARSEMEM_STATIC
+config SPARSEMEM_VMEMMAP_ENABLE
+ bool
+
+config SPARSEMEM_VMEMMAP
+ bool "Sparse Memory virtual memmap"
+ depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
+ default y
+ help
+ SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
+ pfn_to_page and page_to_pfn operations. This is the most
+ efficient option when sufficient kernel resources are available.
+
# eventually, we can have this option just 'select SPARSEMEM'
config MEMORY_HOTPLUG
bool "Allow for memory hot-add"
depends on SPARSEMEM || X86_64_ACPI_NUMA
- depends on HOTPLUG && !SOFTWARE_SUSPEND && ARCH_ENABLE_MEMORY_HOTPLUG
- depends on (IA64 || X86 || PPC64)
+ depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
+ depends on (IA64 || X86 || PPC64 || SUPERH || S390)
comment "Memory hotplug is currently incompatible with Software Suspend"
- depends on SPARSEMEM && HOTPLUG && SOFTWARE_SUSPEND
+ depends on SPARSEMEM && HOTPLUG && HIBERNATION
config MEMORY_HOTPLUG_SPARSE
def_bool y
depends on SPARSEMEM && MEMORY_HOTPLUG
+config MEMORY_HOTREMOVE
+ bool "Allow for memory hot remove"
+ depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
+ depends on MIGRATION
+
+#
+# If we have space for more page flags then we can enable additional
+# optimizations and functionality.
+#
+# Regular Sparsemem takes page flag bits for the sectionid if it does not
+# use a virtual memmap. Disable extended page flags for 32 bit platforms
+# that require the use of a sectionid in the page flags.
+#
+config PAGEFLAGS_EXTENDED
+ def_bool y
+ depends on 64BIT || SPARSEMEM_VMEMMAP || !NUMA || !SPARSEMEM
+
# Heavily threaded applications may benefit from splitting the mm-wide
# page_table_lock, so that faults on different parts of the user address
# space can be handled with less contention: split it at this NR_CPUS.
config MIGRATION
bool "Page migration"
def_bool y
- depends on NUMA
+ depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
help
Allows the migration of the physical location of pages of processes
while the virtual addresses are not changed. This is useful for
example on NUMA systems to put pages nearer to the processors accessing
the page.
-config RESOURCES_64BIT
- bool "64 bit Memory and IO resources (EXPERIMENTAL)" if (!64BIT && EXPERIMENTAL)
- default 64BIT
- help
- This option allows memory and IO resources to be 64 bit.
+config PHYS_ADDR_T_64BIT
+ def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
config ZONE_DMA_FLAG
int
default "0" if !ZONE_DMA
default "1"
+config BOUNCE
+ def_bool y
+ depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
+
config NR_QUICK
int
depends on QUICKLIST
+ default "2" if SUPERH || AVR32
default "1"
+config VIRT_TO_BUS
+ def_bool y
+ depends on !ARCH_NO_VIRT_TO_BUS
+
+config UNEVICTABLE_LRU
+ bool "Add LRU list to track non-evictable pages"
+ default y
+ 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.
+
+ See Documentation/vm/unevictable-lru.txt for more information.
+
+config HAVE_MLOCK
+ bool
+ default y if MMU=y
+
+config HAVE_MLOCKED_PAGE_BIT
+ bool
+ default y if HAVE_MLOCK=y && UNEVICTABLE_LRU=y
+
+config MMU_NOTIFIER
+ bool
+
+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.
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