This commit introduces documentation for mTHP split counters in transhuge.rst. 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 f82300b9193f..35d574a531c8 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -475,6 +475,22 @@ anon_swpout_fallback Usually because failed to allocate some continuous swap space for the huge page. +split_page + is incremented every time a huge page is 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 all PMD/PTE mapped with the huge page. + +split_page_failed + is incremented if kernel fails to split huge + page. This can happen if the page was pinned by somebody. + +deferred_split_page + 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 -- 2.33.1
