Hi Barry, Thanks a lot for taking time to review! On Sat, Jun 29, 2024 at 11:08 AM Barry Song <21cnbao@xxxxxxxxx> wrote: > > On Sat, Jun 29, 2024 at 1:09 AM Lance Yang <ioworker0@xxxxxxxxx> wrote: > > > > 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> > > Reviewed-by: Barry Song <baohua@xxxxxxxxxx> Have a nice weekend ;) Lance > > > --- > > 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 > >
