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authorHugh Dickins <hughd@google.com>2013-02-22 19:36:03 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 20:50:23 -0500
commit8fdb3dbf02335d96bf170321381522709ba63a0c (patch)
tree5c81a212ef5960298ec4d284640c38f707f5dad6 /Documentation
parent49cd0a5c290f99deca3463d16c3c1c7240107889 (diff)
ksm: add some comments
Added slightly more detail to the Documentation of merge_across_nodes, a few comments in areas indicated by review, and renamed get_ksm_page()'s argument from "locked" to "lock_it". No functional change. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Petr Holasek <pholasek@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Izik Eidus <izik.eidus@ravellosystems.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/vm/ksm.txt16
1 files changed, 12 insertions, 4 deletions
diff --git a/Documentation/vm/ksm.txt b/Documentation/vm/ksm.txt
index 25cc89ba811b..f34a8ee6f860 100644
--- a/Documentation/vm/ksm.txt
+++ b/Documentation/vm/ksm.txt
@@ -60,10 +60,18 @@ sleep_millisecs - how many milliseconds ksmd should sleep before next scan
60 60
61merge_across_nodes - specifies if pages from different numa nodes can be merged. 61merge_across_nodes - specifies if pages from different numa nodes can be merged.
62 When set to 0, ksm merges only pages which physically 62 When set to 0, ksm merges only pages which physically
63 reside in the memory area of same NUMA node. It brings 63 reside in the memory area of same NUMA node. That brings
64 lower latency to access to shared page. Value can be 64 lower latency to access of shared pages. Systems with more
65 changed only when there is no ksm shared pages in system. 65 nodes, at significant NUMA distances, are likely to benefit
66 Default: 1 66 from the lower latency of setting 0. Smaller systems, which
67 need to minimize memory usage, are likely to benefit from
68 the greater sharing of setting 1 (default). You may wish to
69 compare how your system performs under each setting, before
70 deciding on which to use. merge_across_nodes setting can be
71 changed only when there are no ksm shared pages in system:
72 set run 2 to unmerge pages first, then to 1 after changing
73 merge_across_nodes, to remerge according to the new setting.
74 Default: 1 (merging across nodes as in earlier releases)
67 75
68run - set 0 to stop ksmd from running but keep merged pages, 76run - set 0 to stop ksmd from running but keep merged pages,
69 set 1 to run ksmd e.g. "echo 1 > /sys/kernel/mm/ksm/run", 77 set 1 to run ksmd e.g. "echo 1 > /sys/kernel/mm/ksm/run",