Commit 75d7dd41 authored by Stefan Roesch's avatar Stefan Roesch Committed by Andrew Morton
Browse files

mm/ksm: document smart scan mode 

This adds documentation for the smart scan mode of KSM.

[akpm@linux-foundation.org: fix typo]
[akpm@linux-foundation.org: document that smart_scan defaults to on]
Link: https://lkml.kernel.org/r/20230926040939.516161-4-shr@devkernel.io


Signed-off-by: default avatarStefan Roesch <shr@devkernel.io>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e5a68991

Documentation/admin-guide/mm/ksm.rst

+9 −0
Original line number Diff line number Diff line
@@ -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