diff options
author | Hugh Dickins <hughd@google.com> | 2013-02-22 19:36:03 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-23 20:50:23 -0500 |
commit | 8fdb3dbf02335d96bf170321381522709ba63a0c (patch) | |
tree | 5c81a212ef5960298ec4d284640c38f707f5dad6 /Documentation | |
parent | 49cd0a5c290f99deca3463d16c3c1c7240107889 (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.txt | 16 |
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 | ||
61 | merge_across_nodes - specifies if pages from different numa nodes can be merged. | 61 | merge_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 | ||
68 | run - set 0 to stop ksmd from running but keep merged pages, | 76 | run - 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", |