+ ksm-add-zero_pages_sharing-documentation.patch added to mm-unstable branch

+ ksm-add-zero_pages_sharing-documentation.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: ksm: add zero_pages_sharing documentation
has been added to the -mm mm-unstable branch.  Its filename is
     ksm-add-zero_pages_sharing-documentation.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ksm-add-zero_pages_sharing-documentation.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: xu xin <xu.xin16@zte.com.cn>
Subject: ksm: add zero_pages_sharing documentation
Date: Fri, 30 Dec 2022 09:17:28 +0800 (CST)

When enabling use_zero_pages, pages_sharing cannot represent how much
memory saved indeed.  zero_pages_sharing + pages_sharing does.  add the
description of zero_pages_sharing.

Link: https://lkml.kernel.org/r/202212300917284911971@zte.com.cn
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Jiang Xuexin <jiang.xuexin@zte.com.cn>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/Documentation/admin-guide/mm/ksm.rst~ksm-add-zero_pages_sharing-documentation
+++ a/Documentation/admin-guide/mm/ksm.rst
@@ -173,6 +173,13 @@ stable_node_chains
         the number of KSM pages that hit the ``max_page_sharing`` limit
 stable_node_dups
         number of duplicated KSM pages
+zero_pages_sharing
+        how many empty pages are sharing kernel zero page(s) instead of
+        with each other as it would happen normally. Only effective when
+        enabling ``use_zero_pages`` knob.
+
+When enabling ``use_zero_pages``, the sum of ``pages_sharing`` +
+``zero_pages_sharing`` represents how much really saved by KSM.
 
 A high ratio of ``pages_sharing`` to ``pages_shared`` indicates good
 sharing, but a high ratio of ``pages_unshared`` to ``pages_sharing``
_

Patches currently in -mm which might be from xu.xin16@zte.com.cn are

ksm-abstract-the-function-try_to_get_old_rmap_item.patch
ksm-support-unsharing-zero-pages-placed-by-ksm.patch
ksm-count-all-zero-pages-placed-by-ksm.patch
ksm-count-zero-pages-for-each-process.patch
ksm-add-zero_pages_sharing-documentation.patch
selftest-add-testing-unsharing-and-counting-ksm-zero-page.patch