/proc/kpageflags - physical pages frame masks
/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.
proc(5)