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)