path: root/init
diff options
authorMel Gorman <mel@csn.ul.ie>2007-10-16 01:25:50 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 09:42:59 -0700
commitb92a6edd4b77a8794adb497280beea5df5e59a14 (patch)
tree396ea5cf2b53fc066e949c443f03747ec868de1e /init
parent535131e6925b4a95f321148ad7293f496e0e58d7 (diff)
Add a configure option to group pages by mobility
The grouping mechanism has some memory overhead and a more complex allocation path. This patch allows the strategy to be disabled for small memory systems or if it is known the workload is suffering because of the strategy. It also acts to show where the page groupings strategy interacts with the standard buddy allocator. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'init')
1 files changed, 13 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 54f31a191b8..bab643f7717 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -607,6 +607,19 @@ config BASE_SMALL
default 0 if BASE_FULL
default 1 if !BASE_FULL
+ 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"