20. NOPAGE
21. KSM
22. THP
+ 23. BALLOON
+ 24. ZERO_PAGE
Short descriptions to the page flags:
22. THP
contiguous pages which construct transparent hugepages
+23. BALLOON
+ balloon compaction page
+
+24. ZERO_PAGE
+ zero page for pfn_zero or huge_zero page
+
[IO related page flags]
1. ERROR IO error occurred
3. UPTODATE page has up-to-date data