Add a configure option to group pages by mobility

[safe/jmp/linux-2.6] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index 54f31a1..bab643f 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -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