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 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
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.