From: Huang Ying <ying.hu...@intel.com>
Add document for newly added thp_swpout, thp_swpout_fallback fields in
/proc/vmstat.
Signed-off-by: "Huang, Ying" <ying.hu...@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com>
Cc: Andrea Arcangeli <aarca...@redhat.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
---
Documentation/vm/transhuge.rst | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/Documentation/vm/transhuge.rst b/Documentation/vm/transhuge.rst
index 569d182cc973..2c6867fca6ff 100644
--- a/Documentation/vm/transhuge.rst
+++ b/Documentation/vm/transhuge.rst
@@ -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
--
2.16.1
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