Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...

[pandora-kernel.git] / Documentation / sysctl / vm.txt

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 2dc246a..7cee902 100644 (file)
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -28,7 +28,7 @@ Currently, these files are in /proc/sys/vm:
 - block_dump
 - drop-caches
 - zone_reclaim_mode
-- zone_reclaim_interval
+- min_unmapped_ratio
 - panic_on_oom
 
 ==============================================================
@@ -167,17 +167,18 @@ use of files and builds up large slab caches. However, the slab
 shrink operation is global, may take a long time and free slabs
 in all nodes of the system.
 
-================================================================
+=============================================================
 
-zone_reclaim_interval:
+min_unmapped_ratio:
 
-The time allowed for off node allocations after zone reclaim
-has failed to reclaim enough pages to allow a local allocation.
+This is available only on NUMA kernels.
 
-Time is set in seconds and set by default to 30 seconds.
+A percentage of the file backed pages in each zone.  Zone reclaim will only
+occur if more than this percentage of pages are file backed and unmapped.
+This is to insure that a minimal amount of local pages is still available for
+file I/O even if the node is overallocated.
 
-Reduce the interval if undesired off node allocations occur. However, too
-frequent scans will have a negative impact onoff node allocation performance.
+The default is 1 percent.
 
 =============================================================