From b92a6edd4b77a8794adb497280beea5df5e59a14 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 16 Oct 2007 01:25:50 -0700 Subject: 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 Signed-off-by: Joel Schopp Cc: Andy Whitcroft Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/Kconfig | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'init') diff --git a/init/Kconfig b/init/Kconfig index 54f31a191b88..bab643f7717f 100644 --- 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 -- cgit v1.2.3