From: xu xin <xu.xin16@xxxxxxxxxx>
This updates ksm_stat description in cgroup-v1/memory.rst.
Signed-off-by: xu xin <xu.xin16@xxxxxxxxxx>
---
Documentation/admin-guide/cgroup-v1/memory.rst | 36 ++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst
index d6b1db8cc7eb..a67e573c43d2 100644
--- a/Documentation/admin-guide/cgroup-v1/memory.rst
+++ b/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -97,6 +97,8 @@ Brief summary of control files.
used.
memory.numa_stat show the number of memory usage per numa
node
+ memory.ksm_stat show the statistic information about various ksm
+ counters
memory.kmem.limit_in_bytes Deprecated knob to set and read the kernel
memory hard limit. Kernel hard limit is not
supported since 5.16. Writing any value to
@@ -674,6 +676,40 @@ The output format of memory.numa_stat is::
The "total" count is sum of file + anon + unevictable.
+.. _memcg_ksm_stat:
+
+5.7 ksm_stat
+------------
+
+When CONFIG_KSM is enabled, the ksm_stat file can be used to observe the ksm
+merging status of the processes within an memory cgroup.
+
+The output format of memory.ksm_stat is::
+
+ ksm_rmap_items <number>
+ ksm_zero_pages <number>
+ ksm_merging_pages <number>
+ ksm_profit <number>
+
+The "ksm_rmap_items" count specifies the number of ksm_rmap_item structures in
+use. The structureksm_rmap_item stores the reverse mapping information for
+virtual addresses. KSM will generate a ksm_rmap_item for each ksm-scanned page
+of the process.
+
+The "ksm_zero_pages" count specifies represent how many empty pages are merged
+with kernel zero pages by KSM, which is useful when /sys/kernel/mm/ksm/use_zero_pages
+is enabled.
+
+The "ksm_merging_pages" count specifies how many pages of this process are involved
+in KSM merging (not including ksm_zero_pages).
+
+The "ksm_process_profit" count specifies the profit that KSM brings (Saved bytes).
+KSM can save memory by merging identical pages, but also can consume additional
+memory, because it needs to generate a number of rmap_items to save each scanned
+page's brief rmap information. Some of these pages may be merged, but some may not
+be abled to be merged after being checked several times, which are unprofitable
+memory consumed.
+
6. Hierarchy support
====================
--
2.15.2
