From: Song Hu <husong@kylinos.cn>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: david@kernel.org, ljs@kernel.org, ziy@nvidia.com,
baolin.wang@linux.alibaba.com, liam@infradead.org,
nico.pache@linux.dev, ryan.roberts@arm.com, dev.jain@arm.com,
baohua@kernel.org, lance.yang@linux.dev, usama.arif@linux.dev,
vbabka@kernel.org, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org,
rdunlap@infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Song Hu <husong@kylinos.cn>
Subject: [PATCH 1/2] Docs/ABI: document transparent_hugepage/shrink_underused
Date: Wed, 12 Aug 2026 16:03:12 +0800 [thread overview]
Message-ID: <20260812080313.330413-2-husong@kylinos.cn> (raw)
In-Reply-To: <20260812080313.330413-1-husong@kylinos.cn>
The shrink_underused knob was added in commit 81d3ff3c6f76 ("mm: add
sysfs entry to disable splitting underused THPs") but is missing from
Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage, although
transhuge.rst already documents it. Add the ABI entry.
Signed-off-by: Song Hu <husong@kylinos.cn>
---
.../ABI/testing/sysfs-kernel-mm-transparent-hugepage | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
index 7bfbb9cc2c11..bbdfae2c0caa 100644
--- a/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
+++ b/Documentation/ABI/testing/sysfs-kernel-mm-transparent-hugepage
@@ -10,9 +10,19 @@ Description:
- hpage_pmd_size
- khugepaged
- shmem_enabled
+ - shrink_underused
- use_zero_page
- subdirectories of the form hugepages-<size>kB, where <size>
is the page size of the hugepages supported by the kernel/CPU
combination.
See Documentation/admin-guide/mm/transhuge.rst for details.
+
+What: /sys/kernel/mm/transparent_hugepage/shrink_underused
+Date: Sep 2024
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Reading and writing this file controls whether khugepaged
+ splits underused transparent huge pages (THPs) under memory
+ pressure. A THP is considered underused when its number of
+ zero-filled pages is above max_ptes_none. Enabled by default;
+ writing 0 disables the splitting and 1 enables it.
--
2.43.0
next prev parent reply other threads:[~2026-08-12 8:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-12 8:03 [PATCH 0/2] Docs: THP documentation fixes Song Hu
2026-08-12 8:03 ` Song Hu [this message]
2026-08-12 8:58 ` [PATCH 1/2] Docs/ABI: document transparent_hugepage/shrink_underused Lorenzo Stoakes (ARM)
2026-08-12 8:03 ` [PATCH 2/2] Docs/mm: fix THP policy counts in transhuge Song Hu
2026-08-12 8:41 ` Baolin Wang
2026-08-12 9:27 ` Lorenzo Stoakes (ARM)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260812080313.330413-2-husong@kylinos.cn \
--to=husong@kylinos.cn \
--cc=akpm@linux-foundation.org \
--cc=baohua@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=corbet@lwn.net \
--cc=david@kernel.org \
--cc=dev.jain@arm.com \
--cc=lance.yang@linux.dev \
--cc=liam@infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=mhocko@suse.com \
--cc=nico.pache@linux.dev \
--cc=rdunlap@infradead.org \
--cc=rppt@kernel.org \
--cc=ryan.roberts@arm.com \
--cc=skhan@linuxfoundation.org \
--cc=surenb@google.com \
--cc=usama.arif@linux.dev \
--cc=vbabka@kernel.org \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox