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| author |   Stefan Roesch <shr@devkernel.io> | 2023-09-25 21:09:38 -0700 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2023-10-16 15:44:39 -0700 |
| commit | 75d7dd4138edd54f3b539698cb4c78a8494d305c (patch) | |
| tree | 2c2bd73c49bb96a1a7b58a9c00af9f91f9699e6a /Documentation/admin-guide/mm | |
| parent | mm/ksm: add pages_skipped metric (diff) | |
| download | wireguard-linux-75d7dd4138edd54f3b539698cb4c78a8494d305c.tar.xz wireguard-linux-75d7dd4138edd54f3b539698cb4c78a8494d305c.zip | |
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: Stefan Roesch <shr@devkernel.io>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide/mm')
| -rw-r--r-- | Documentation/admin-guide/mm/ksm.rst | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 776f244bdae4..9d235c1bbbf2 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 |