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Diffstat (limited to 'man5/proc_pid_pagemap.5')
| -rw-r--r-- | man5/proc_pid_pagemap.5 | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/man5/proc_pid_pagemap.5 b/man5/proc_pid_pagemap.5 new file mode 100644 index 0000000..436e2c5 --- /dev/null +++ b/man5/proc_pid_pagemap.5 @@ -0,0 +1,77 @@ +.\" Copyright (C) 1994, 1995, Daniel Quinlan <quinlan@yggdrasil.com> +.\" Copyright (C) 2002-2008, 2017, Michael Kerrisk <mtk.manpages@gmail.com> +.\" Copyright (C) 2023, Alejandro Colomar <alx@kernel.org> +.\" +.\" SPDX-License-Identifier: GPL-3.0-or-later +.\" +.TH proc_pid_pagemap 5 2023-08-15 "Linux man-pages 6.7" +.SH NAME +/proc/pid/pagemap \- mapping of virtual pages +.SH DESCRIPTION +.TP +.IR /proc/ pid /pagemap " (since Linux 2.6.25)" +This file shows the mapping of each of the process's virtual pages +into physical page frames or swap area. +It contains one 64-bit value for each virtual page, +with the bits set as follows: +.RS +.TP +63 +If set, the page is present in RAM. +.TP +62 +If set, the page is in swap space +.TP +61 (since Linux 3.5) +The page is a file-mapped page or a shared anonymous page. +.TP +60\[en]58 (since Linux 3.11) +Zero +.\" Not quite true; see commit 541c237c0923f567c9c4cabb8a81635baadc713f +.TP +57 (since Linux 5.14) +If set, the page is write-protected through +.BR userfaultfd (2). +.TP +56 (since Linux 4.2) +.\" commit 77bb499bb60f4b79cca7d139c8041662860fcf87 +.\" commit 83b4b0bb635eee2b8e075062e4e008d1bc110ed7 +The page is exclusively mapped. +.TP +55 (since Linux 3.11) +PTE is soft-dirty +(see the kernel source file +.IR Documentation/admin\-guide/mm/soft\-dirty.rst ). +.TP +54\[en]0 +If the page is present in RAM (bit 63), then these bits +provide the page frame number, which can be used to index +.I /proc/kpageflags +and +.IR /proc/kpagecount . +If the page is present in swap (bit 62), +then bits 4\[en]0 give the swap type, and bits 54\[en]5 encode the swap offset. +.RE +.IP +Before Linux 3.11, bits 60\[en]55 were +used to encode the base-2 log of the page size. +.IP +To employ +.IR /proc/ pid /pagemap +efficiently, use +.IR /proc/ pid /maps +to determine which areas of memory are actually mapped and seek +to skip over unmapped regions. +.IP +The +.IR /proc/ pid /pagemap +file is present only if the +.B CONFIG_PROC_PAGE_MONITOR +kernel configuration option is enabled. +.IP +Permission to access this file is governed by a ptrace access mode +.B PTRACE_MODE_READ_FSCREDS +check; see +.BR ptrace (2). +.SH SEE ALSO +.BR proc (5) |