linux-kernel - [RESEND RFC PATCH v1 15/20] docs: document new procfs ksm knobs

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Message-Id: <20230123173748.1734238-16-shr@devkernel.io>
Date:   Mon, 23 Jan 2023 09:37:43 -0800
From:   Stefan Roesch <shr@...kernel.io>
To:     linux-mm@...ck.org
Cc:     shr@...kernel.io, linux-doc@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-kselftest@...r.kernel.org, linux-trace-kernel@...r.kernel.org
Subject: [RESEND RFC PATCH v1 15/20] docs: document new procfs ksm knobs

This documents the ksm_process_profit and ksm_merge_type settings in
ksm_stat.

Signed-off-by: Stefan Roesch <shr@...kernel.io>
---
 Documentation/admin-guide/mm/ksm.rst | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
index 72189bf1283e..70896f01d641 100644
--- a/Documentation/admin-guide/mm/ksm.rst
+++ b/Documentation/admin-guide/mm/ksm.rst
@@ -211,7 +211,8 @@ several times, which are unprofitable memory consumed.
 			  ksm_rmap_items * sizeof(rmap_item).
 
    where ksm_merging_pages is shown under the directory ``/proc/<pid>/``,
-   and ksm_rmap_items is shown in ``/proc/<pid>/ksm_stat``.
+   and ksm_rmap_items is shown in ``/proc/<pid>/ksm_stat``. The process profit
+   is also shown in ``/proc/<pid>/ksm_stat`` as ksm_process_profit.
 
 From the perspective of application, a high ratio of ``ksm_rmap_items`` to
 ``ksm_merging_pages`` means a bad madvise-applied policy, so developers or
@@ -222,6 +223,9 @@ so if the ``ksm_rmap_items/ksm_merging_pages`` ratio exceeds 64 on 64-bit CPU
 or exceeds 128 on 32-bit CPU, then the app's madvise policy should be dropped,
 because the ksm profit is approximately zero or negative.
 
+The ksm_merge_type in ``/proc/<pid>/ksm_stat`` shows the merge type of the
+process. Valid values are ``none``, ``madvise`` and ``process``.
+
 Monitoring KSM events
 =====================
 
-- 
2.30.2