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authorChristoph Lameter <clameter@sgi.com>2006-01-18 17:42:32 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-18 19:20:17 -0800
commit1743660b911bfb849b1fb33830522254561b9f9b (patch)
tree82bfd84f534e7a571667916f90e2492c7148cbac /Documentation
parent9eeff2395e3cfd05c9b2e6074ff943a34b0c5c21 (diff)
downloadlinux-1743660b911bfb849b1fb33830522254561b9f9b.tar.bz2
[PATCH] Zone reclaim: proc override
proc support for zone reclaim This patch creates a proc entry /proc/sys/vm/zone_reclaim_mode that may be used to override the automatic determination of the zone reclaim made on bootup. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/sysctl/vm.txt18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 6910c0136f8d..391dd64363e7 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm:
- laptop_mode
- block_dump
- drop-caches
+- zone_reclaim_mode
==============================================================
@@ -120,3 +121,20 @@ set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8)
The initial value is zero. Kernel does not use this value at boot time to set
the high water marks for each per cpu page list.
+
+===============================================================
+
+zone_reclaim_mode:
+
+This is set during bootup to 1 if it is determined that pages from
+remote zones will cause a significant performance reduction. The
+page allocator will then reclaim easily reusable pages (those page
+cache pages that are currently not used) before going off node.
+
+The user can override this setting. It may be beneficial to switch
+off zone reclaim if the system is used for a file server and all
+of memory should be used for caching files from disk.
+
+It may be beneficial to switch this on if one wants to do zone
+reclaim regardless of the numa distances in the system.
+