On 04.07.24 03:29, Lance Yang wrote:
This commit introduces documentation for mTHP split counters in
transhuge.rst.
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
Signed-off-by: Mingzhe Yang <mingzhe.yang@xxxxxx>
Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
---
Documentation/admin-guide/mm/transhuge.rst | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index 1f72b00af5d3..0830aa173a8b 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -369,10 +369,6 @@ also applies to the regions registered in khugepaged.
Monitoring usage
================
-.. note::
- Currently the below counters only record events relating to
- PMD-sized THP. Events relating to other THP sizes are not included.
-
The number of PMD-sized anonymous transparent huge pages currently used by the
system is available by reading the AnonHugePages field in ``/proc/meminfo``.
To identify what applications are using PMD-sized anonymous transparent huge
@@ -514,6 +510,22 @@ file_fallback_charge
falls back to using small pages even though the allocation was
successful.
+split
+ is incremented every time a huge page is successfully split into
+ smaller orders. This can happen for a variety of reasons but a
+ common reason is that a huge page is old and is being reclaimed.
+ This action implies splitting any block mappings into PTEs.
+
+split_failed
+ is incremented if kernel fails to split huge
+ page. This can happen if the page was pinned by somebody.
+
+split_deferred
+ is incremented when a huge page is put onto split
+ queue. This happens when a huge page is partially unmapped and
+ splitting it would free up some memory. Pages on split queue are
+ going to be split under memory pressure.
".. if splitting is possible." ;)
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
