mm, THP, doc: Add document for thp_swpout/thp_swpout_fallback

Add document for newly added thp_swpout, thp_swpout_fallback fields in
/proc/vmstat.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Huang Ying 2018-05-09 16:23:41 +08:00 committed by Jonathan Corbet
parent 9167b942d5
commit 8d420f6c27

View File

@ -355,6 +355,15 @@ thp_zero_page_alloc_failed
is incremented if kernel fails to allocate
huge zero page and falls back to using small pages.
thp_swpout
is incremented every time a huge page is swapout in one
piece without splitting.
thp_swpout_fallback
is incremented if a huge page has to be split before swapout.
Usually because failed to allocate some continuous swap space
for the huge page.
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