This adds documentation for the smart scan mode of KSM.
Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
---
Documentation/admin-guide/mm/ksm.rst | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
index 776f244bdae4..2b38a8bb08af 100644
--- a/Documentation/admin-guide/mm/ksm.rst
+++ b/Documentation/admin-guide/mm/ksm.rst
@@ -155,6 +155,15 @@ stable_node_chains_prune_millisecs
scan. It's a noop if not a single KSM page hit the
``max_page_sharing`` yet.
+smart_scan
+ Historically KSM checked every candidate page for each scan. It did
+ not take into account historic information. When smart scan is
+ enabled, pages that have previously not been de-duplicated get
+ skipped. How often these pages are skipped depends on how often
+ de-duplication has already been tried and failed. By default this
+ optimization is enabled. The ``pages_skipped`` metric shows how
+ effective the setting is.
+
The effectiveness of KSM and MADV_MERGEABLE is shown in ``/sys/kernel/mm/ksm/``:
general_profit
--
2.39.3
