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NAME | DESCRIPTION | SEE ALSO | COLOPHON |
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proc_pid_pagemap(5) File Formats Manual proc_pid_pagemap(5)
/proc/pid/pagemap - mapping of virtual pages
/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:
63 If set, the page is present in RAM.
62 If set, the page is in swap space
61 (since Linux 3.5)
The page is a file-mapped page or a shared
anonymous page.
60–58 (since Linux 3.11)
Zero
57 (since Linux 5.14)
If set, the page is write-protected through
userfaultfd(2).
56 (since Linux 4.2)
The page is exclusively mapped.
55 (since Linux 3.11)
PTE is soft-dirty (see the kernel source file
Documentation/admin-guide/mm/soft-dirty.rst).
54–0 If the page is present in RAM (bit 63), then these
bits provide the page frame number, which can be
used to index /proc/kpageflags and
/proc/kpagecount. If the page is present in swap
(bit 62), then bits 4–0 give the swap type, and
bits 54–5 encode the swap offset.
Before Linux 3.11, bits 60–55 were used to encode the
base-2 log of the page size.
To employ /proc/pid/pagemap efficiently, use
/proc/pid/maps to determine which areas of memory are
actually mapped and seek to skip over unmapped regions.
The /proc/pid/pagemap file is present only if the
CONFIG_PROC_PAGE_MONITOR kernel configuration option is
enabled.
Permission to access this file is governed by a ptrace
access mode PTRACE_MODE_READ_FSCREDS check; see ptrace(2).
proc(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
[email protected]
Linux man-pages 6.9.1 2024-05-02 proc_pid_pagemap(5)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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