The quilt patch titled
Subject: mm: add docs for per-order mTHP split counters
has been removed from the -mm tree. Its filename was
mm-add-docs-for-per-order-mthp-split-counters.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Lance Yang <ioworker0@xxxxxxxxx>
Subject: mm: add docs for per-order mTHP split counters
Date: Fri, 28 Jun 2024 21:07:50 +0800
This commit introduces documentation for mTHP split counters in
transhuge.rst.
[ioworker0@xxxxxxxxx: improve the doc as suggested by Ryan]
Link: https://lkml.kernel.org/r/20240704012905.42971-3-ioworker0@xxxxxxxxx
[ioworker0@xxxxxxxxx: tweak Documentation/admin-guide/mm/transhuge.rst]
Link: https://lkml.kernel.org/r/20240707013659.1151-1-ioworker0@xxxxxxxxx
Link: https://lkml.kernel.org/r/20240628130750.73097-3-ioworker0@xxxxxxxxx
Signed-off-by: Mingzhe Yang <mingzhe.yang@xxxxxx>
Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
Reviewed-by: Barry Song <baohua@xxxxxxxxxx>
Reviewed-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Bang Li <libang.li@xxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/mm/transhuge.rst | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
--- a/Documentation/admin-guide/mm/transhuge.rst~mm-add-docs-for-per-order-mthp-split-counters
+++ a/Documentation/admin-guide/mm/transhuge.rst
@@ -369,10 +369,6 @@ also applies to the regions registered i
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 +510,21 @@ 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.
+
+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.
+
As the system ages, allocating huge pages may be expensive as the
system uses memory compaction to copy data around memory to free a
huge page for use. There are some counters in ``/proc/vmstat`` to help
_
Patches currently in -mm which might be from ioworker0@xxxxxxxxx are
