Remove implementation details from sysfs parameter descriptions.
Also move the paragraph discussing fragmentation issues and their possible
solution to the "Design" section.
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
---
Documentation/vm/ksm.rst | 21 ++++++++++-----------
1 file changed, 10 insertions(+), 11 deletions(-)
diff --git a/Documentation/vm/ksm.rst b/Documentation/vm/ksm.rst
index 18d7c71..afcf5a8 100644
--- a/Documentation/vm/ksm.rst
+++ b/Documentation/vm/ksm.rst
@@ -170,10 +170,9 @@ pages_volatile
full_scans
how many times all mergeable areas have been scanned
stable_node_chains
- number of stable node chains allocated, this is effectively
the number of KSM pages that hit the ``max_page_sharing`` limit
stable_node_dups
- number of stable node dups queued into the stable_node chains
+ number of duplicated KSM pages
A high ratio of ``pages_sharing`` to ``pages_shared`` indicates good
sharing, but a high ratio of ``pages_unshared`` to ``pages_sharing``
@@ -185,15 +184,6 @@ The maximum possible ``pages_sharing/pages_shared`` ratio is limited by the
``max_page_sharing`` tunable. To increase the ratio ``max_page_sharing`` must
be increased accordingly.
-The ``stable_node_dups/stable_node_chains`` ratio is also affected by the
-``max_page_sharing`` tunable, and an high ratio may indicate fragmentation
-in the stable_node dups, which could be solved by introducing
-fragmentation algorithms in ksmd which would refile rmap_items from
-one stable_node dup to another stable_node dup, in order to free up
-stable_node "dups" with few rmap_items in them, but that may increase
-the ksmd CPU usage and possibly slowdown the readonly computations on
-the KSM pages of the applications.
-
Design
======
@@ -247,6 +237,15 @@ deduplication factor at the expense of slower worst case for rmap
walks for any KSM page which can happen during swapping, compaction,
NUMA balancing and page migration.
+The ``stable_node_dups/stable_node_chains`` ratio is also affected by the
+``max_page_sharing`` tunable, and an high ratio may indicate fragmentation
+in the stable_node dups, which could be solved by introducing
+fragmentation algorithms in ksmd which would refile rmap_items from
+one stable_node dup to another stable_node dup, in order to free up
+stable_node "dups" with few rmap_items in them, but that may increase
+the ksmd CPU usage and possibly slowdown the readonly computations on
+the KSM pages of the applications.
+
The whole list of stable_node "dups" linked in the stable_node
"chains" is scanned periodically in order to prune stale stable_nodes.
The frequency of such scans is defined by
--
2.7.4
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