This commit introduces documentation for mTHP split counters in transhuge.rst. Signed-off-by: Mingzhe Yang <mingzhe.yang@xxxxxx> Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx> --- Documentation/admin-guide/mm/transhuge.rst | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 1f72b00af5d3..709fe10b60f4 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -514,6 +514,22 @@ 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 + base pages. 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. + 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 -- 2.45.2
