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 --- .../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-kB, where 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 +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