Add a configure option to group pages by mobility

[linux-2.6] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index 37711fe3c01c55d5a454501206dba63948d6f6c0..bab643f7717f2a0be9b2b63d7c4d14acdb5a99e5 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -282,11 +282,11 @@ config CPUSETS
          Say N if unsure.
 
 config FAIR_GROUP_SCHED
-       bool "Fair group cpu scheduler"
-       default n
+       bool "Fair group CPU scheduler"
+       default y
        depends on EXPERIMENTAL
        help
-         This feature lets cpu scheduler recognize task groups and control cpu
+         This feature lets CPU scheduler recognize task groups and control CPU
          bandwidth allocation to such task groups.
 
 choice
@@ -294,11 +294,11 @@ choice
        prompt "Basis for grouping tasks"
        default FAIR_USER_SCHED
 
-       config FAIR_USER_SCHED
-               bool "user id"
-               help
-                 This option will choose userid as the basis for grouping
-                 tasks, thus providing equal cpu bandwidth to each user.
+config FAIR_USER_SCHED
+       bool "user id"
+       help
+         This option will choose userid as the basis for grouping
+         tasks, thus providing equal CPU bandwidth to each user.
 
 endchoice
 
@@ -607,6 +607,19 @@ config BASE_SMALL
        default 0 if BASE_FULL
        default 1 if !BASE_FULL
 
+config PAGE_GROUP_BY_MOBILITY
+       bool "Group pages based on their mobility in the page allocator"
+       def_bool y
+       help
+         The standard allocator will fragment memory over time which means
+         that high order allocations will fail even if kswapd is running. If
+         this option is set, the allocator will try and group page types
+         based on their ability to migrate or reclaim. This is a best effort
+         attempt at lowering fragmentation which a few workloads care about.
+         The loss is a more complex allocator that may perform slower. If
+         you are interested in working with large pages, say Y and set
+         /proc/sys/vm/min_free_bytes to 16374. Otherwise say N
+
 menuconfig MODULES
        bool "Enable loadable module support"
        help