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authorHuang Ying <ying.huang@intel.com>2018-05-09 16:23:41 +0800
committerJonathan Corbet <corbet@lwn.net>2018-05-10 15:42:42 -0600
commit8d420f6c27c530e25c057a59575e193dd62bb743 (patch)
tree09bbd1523ecafee50c5a1bd8f5094afee7ec02a7 /Documentation/vm
parent9167b942d53c96e7ddeb59ee0f84930955d7b682 (diff)
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>
Diffstat (limited to 'Documentation/vm')
-rw-r--r--Documentation/vm/transhuge.rst9
1 files changed, 9 insertions, 0 deletions
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