proc_kpageflags(5) File Formats Manual proc_kpageflags(5) NAME /proc/kpageflags - physical pages frame masks DESCRIPTION /proc/kpageflags (since Linux 2.6.25) This file contains 64-bit masks corresponding to each physical page frame; it is indexed by page frame number (see the discussion of /proc/pid/pagemap). The bits are as follows: 0 - KPF_LOCKED 1 - KPF_ERROR 2 - KPF_REFERENCED 3 - KPF_UPTODATE 4 - KPF_DIRTY 5 - KPF_LRU 6 - KPF_ACTIVE 7 - KPF_SLAB 8 - KPF_WRITEBACK 9 - KPF_RECLAIM 10 - KPF_BUDDY 11 - KPF_MMAP (since Linux 2.6.31) 12 - KPF_ANON (since Linux 2.6.31) 13 - KPF_SWAPCACHE (since Linux 2.6.31) 14 - KPF_SWAPBACKED (since Linux 2.6.31) 15 - KPF_COMPOUND_HEAD (since Linux 2.6.31) 16 - KPF_COMPOUND_TAIL (since Linux 2.6.31) 17 - KPF_HUGE (since Linux 2.6.31) 18 - KPF_UNEVICTABLE (since Linux 2.6.31) 19 - KPF_HWPOISON (since Linux 2.6.31) 20 - KPF_NOPAGE (since Linux 2.6.31) 21 - KPF_KSM (since Linux 2.6.32) 22 - KPF_THP (since Linux 3.4) 23 - KPF_BALLOON (since Linux 3.18) 24 - KPF_ZERO_PAGE (since Linux 4.0) 25 - KPF_IDLE (since Linux 4.3) 26 - KPF_PGTABLE (since Linux 4.18) For further details on the meanings of these bits, see the kernel source file Documentation/admin-guide/mm/pagemap.rst. Before Linux 2.6.29, KPF_WRITEBACK, KPF_RECLAIM, KPF_BUDDY, and KPF_LOCKED did not report correctly. The /proc/kpageflags file is present only if the CONFIG_PROC_PAGE_MONITOR kernel configuration option is enabled. SEE ALSO proc(5) Linux man-pages 6.9.1 2024-05-02 proc_kpageflags(5)