mirror of https://github.com/mkerrisk/man-pages
6863 lines
204 KiB
Groff
6863 lines
204 KiB
Groff
.\" Copyright (C) 1994, 1995 by Daniel Quinlan (quinlan@yggdrasil.com)
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.\" and Copyright (C) 2002-2008,2017 Michael Kerrisk <mtk.manpages@gmail.com>
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.\" with networking additions from Alan Cox (A.Cox@swansea.ac.uk)
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.\" and scsi additions from Michael Neuffer (neuffer@mail.uni-mainz.de)
|
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.\" and sysctl additions from Andries Brouwer (aeb@cwi.nl)
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.\" and System V IPC (as well as various other) additions from
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.\" Michael Kerrisk <mtk.manpages@gmail.com>
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_FULL)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
|
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.\" the License, or (at your option) any later version.
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.\"
|
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.\" The GNU General Public License's references to "object code"
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.\" and "executables" are to be interpreted as the output of any
|
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.\" document formatting or typesetting system, including
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.\" intermediate and printed output.
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.\"
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.\" This manual is distributed in the hope that it will be useful,
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.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
|
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.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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.\" GNU General Public License for more details.
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.\"
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.\" You should have received a copy of the GNU General Public
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.\" License along with this manual; if not, see
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.\" <http://www.gnu.org/licenses/>.
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.\" %%%LICENSE_END
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.\"
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.\" Modified 1995-05-17 by faith@cs.unc.edu
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.\" Minor changes by aeb and Marty Leisner (leisner@sdsp.mc.xerox.com).
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.\" Modified 1996-04-13, 1996-07-22 by aeb@cwi.nl
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.\" Modified 2001-12-16 by rwhron@earthlink.net
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.\" Modified 2002-07-13 by jbelton@shaw.ca
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.\" Modified 2002-07-22, 2003-05-27, 2004-04-06, 2004-05-25
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.\" by Michael Kerrisk <mtk.manpages@gmail.com>
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.\" 2004-11-17, mtk -- updated notes on /proc/loadavg
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.\" 2004-12-01, mtk, rtsig-max and rtsig-nr went away in 2.6.8
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.\" 2004-12-14, mtk, updated 'statm', and fixed error in order of list
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.\" 2005-05-12, mtk, updated 'stat'
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.\" 2005-07-13, mtk, added /proc/sys/fs/mqueue/*
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.\" 2005-09-16, mtk, Added /proc/sys/fs/suid_dumpable
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.\" 2005-09-19, mtk, added /proc/zoneinfo
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.\" 2005-03-01, mtk, moved /proc/sys/fs/mqueue/* material to mq_overview.7.
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.\" 2008-06-05, mtk, Added /proc/[pid]/oom_score, /proc/[pid]/oom_adj,
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.\" /proc/[pid]/limits, /proc/[pid]/mountinfo, /proc/[pid]/mountstats,
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.\" and /proc/[pid]/fdinfo/*.
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.\" 2008-06-19, mtk, Documented /proc/[pid]/status.
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.\" 2008-07-15, mtk, added /proc/config.gz
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.\"
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.\" FIXME cross check against Documentation/filesystems/proc.txt
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.\" to see what information could be imported from that file
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.\" into this file.
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.\"
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.TH PROC 5 2021-08-27 "Linux" "Linux Programmer's Manual"
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.SH NAME
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proc \- process information pseudo-filesystem
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.SH DESCRIPTION
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|
The
|
|
.B proc
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|
filesystem is a pseudo-filesystem which provides an interface to
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kernel data structures.
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|
It is commonly mounted at
|
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.IR /proc .
|
|
Typically, it is mounted automatically by the system,
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|
but it can also be mounted manually using a command such as:
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|
.PP
|
|
.in +4n
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|
.EX
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|
mount \-t proc proc /proc
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|
.EE
|
|
.in
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|
.PP
|
|
Most of the files in the
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|
.B proc
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|
filesystem are read-only,
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|
but some files are writable, allowing kernel variables to be changed.
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|
.\"
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|
.SS Mount options
|
|
The
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|
.B proc
|
|
filesystem supports the following mount options:
|
|
.TP
|
|
.BR hidepid "=\fIn\fP (since Linux 3.3)"
|
|
.\" commit 0499680a42141d86417a8fbaa8c8db806bea1201
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|
This option controls who can access the information in
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|
.IR /proc/[pid]
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|
directories.
|
|
The argument,
|
|
.IR n ,
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|
is one of the following values:
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.RS
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|
.TP 4
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|
0
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|
Everybody may access all
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|
.IR /proc/[pid]
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|
directories.
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|
This is the traditional behavior,
|
|
and the default if this mount option is not specified.
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|
.TP
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|
1
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Users may not access files and subdirectories inside any
|
|
.IR /proc/[pid]
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|
directories but their own (the
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|
.IR /proc/[pid]
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|
directories themselves remain visible).
|
|
Sensitive files such as
|
|
.IR /proc/[pid]/cmdline
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|
and
|
|
.IR /proc/[pid]/status
|
|
are now protected against other users.
|
|
This makes it impossible to learn whether any user is running a
|
|
specific program
|
|
(so long as the program doesn't otherwise reveal itself by its behavior).
|
|
.\" As an additional bonus, since
|
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.\" .IR /proc/[pid]/cmdline
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.\" is inaccessible for other users,
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|
.\" poorly written programs passing sensitive information via
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.\" program arguments are now protected against local eavesdroppers.
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|
.TP
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|
2
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|
As for mode 1, but in addition the
|
|
.IR /proc/[pid]
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|
directories belonging to other users become invisible.
|
|
This means that
|
|
.IR /proc/[pid]
|
|
entries can no longer be used to discover the PIDs on the system.
|
|
This doesn't hide the fact that a process with a specific PID value exists
|
|
(it can be learned by other means, for example, by "kill \-0 $PID"),
|
|
but it hides a process's UID and GID,
|
|
which could otherwise be learned by employing
|
|
.BR stat (2)
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|
on a
|
|
.IR /proc/[pid]
|
|
directory.
|
|
This greatly complicates an attacker's task of gathering
|
|
information about running processes (e.g., discovering whether
|
|
some daemon is running with elevated privileges,
|
|
whether another user is running some sensitive program,
|
|
whether other users are running any program at all, and so on).
|
|
.RE
|
|
.TP
|
|
.BR gid "=\fIgid\fP (since Linux 3.3)"
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|
.\" commit 0499680a42141d86417a8fbaa8c8db806bea1201
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Specifies the ID of a group whose members are authorized to
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|
learn process information otherwise prohibited by
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|
.BR hidepid
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|
(i.e., users in this group behave as though
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.I /proc
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|
was mounted with
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|
.IR hidepid=0 ).
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|
This group should be used instead of approaches such as putting
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|
nonroot users into the
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|
.BR sudoers (5)
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|
file.
|
|
.\"
|
|
.SS Overview
|
|
Underneath
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.IR /proc ,
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|
there are the following general groups of files and subdirectories:
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|
.TP
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|
.IR /proc/[pid] " subdirectories"
|
|
Each one of these subdirectories contains files and subdirectories
|
|
exposing information about the process with the corresponding process ID.
|
|
.IP
|
|
Underneath each of the
|
|
.I /proc/[pid]
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directories, a
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|
.I task
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subdirectory contains subdirectories of the form
|
|
.IR task/[tid] ,
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|
which contain corresponding information about each of the threads
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|
in the process, where
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|
.I tid
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|
is the kernel thread ID of the thread.
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|
.IP
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|
The
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|
.I /proc/[pid]
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|
subdirectories are visible when iterating through
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|
.I /proc
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|
with
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|
.BR getdents (2)
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|
(and thus are visible when one uses
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|
.BR ls (1)
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|
to view the contents of
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.IR /proc ).
|
|
.TP
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|
.IR /proc/[tid] " subdirectories"
|
|
Each one of these subdirectories contains files and subdirectories
|
|
exposing information about the thread with the corresponding thread ID.
|
|
The contents of these directories are the same as the corresponding
|
|
.IR /proc/[pid]/task/[tid]
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|
directories.
|
|
.IP
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|
The
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|
.I /proc/[tid]
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|
subdirectories are
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|
.I not
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|
visible when iterating through
|
|
.I /proc
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|
with
|
|
.BR getdents (2)
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|
(and thus are
|
|
.I not
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|
visible when one uses
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|
.BR ls (1)
|
|
to view the contents of
|
|
.IR /proc ).
|
|
.TP
|
|
.I /proc/self
|
|
When a process accesses this magic symbolic link,
|
|
it resolves to the process's own
|
|
.I /proc/[pid]
|
|
directory.
|
|
.TP
|
|
.I /proc/thread\-self
|
|
When a thread accesses this magic symbolic link,
|
|
it resolves to the process's own
|
|
.I /proc/self/task/[tid]
|
|
directory.
|
|
.TP
|
|
.I /proc/[a\-z]*
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|
Various other files and subdirectories under
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|
.I /proc
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|
expose system-wide information.
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|
.PP
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|
All of the above are described in more detail below.
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.\"
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|
.SS Files and directories
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|
The following list provides details of many of the files and directories
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|
under the
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|
.I /proc
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|
hierarchy.
|
|
.TP
|
|
.I /proc/[pid]
|
|
There is a numerical subdirectory for each running process; the
|
|
subdirectory is named by the process ID.
|
|
Each
|
|
.I /proc/[pid]
|
|
subdirectory contains the pseudo-files and directories described below.
|
|
.IP
|
|
The files inside each
|
|
.I /proc/[pid]
|
|
directory are normally owned by the effective user and
|
|
effective group ID of the process.
|
|
However, as a security measure, the ownership is made
|
|
.IR root:root
|
|
if the process's "dumpable" attribute is set to a value other than 1.
|
|
.IP
|
|
Before Linux 4.11,
|
|
.\" commit 68eb94f16227336a5773b83ecfa8290f1d6b78ce
|
|
.IR root:root
|
|
meant the "global" root user ID and group ID
|
|
(i.e., UID 0 and GID 0 in the initial user namespace).
|
|
Since Linux 4.11,
|
|
if the process is in a noninitial user namespace that has a
|
|
valid mapping for user (group) ID 0 inside the namespace, then
|
|
the user (group) ownership of the files under
|
|
.I /proc/[pid]
|
|
is instead made the same as the root user (group) ID of the namespace.
|
|
This means that inside a container,
|
|
things work as expected for the container "root" user.
|
|
.IP
|
|
The process's "dumpable" attribute may change for the following reasons:
|
|
.RS
|
|
.IP * 3
|
|
The attribute was explicitly set via the
|
|
.BR prctl (2)
|
|
.B PR_SET_DUMPABLE
|
|
operation.
|
|
.IP *
|
|
The attribute was reset to the value in the file
|
|
.IR /proc/sys/fs/suid_dumpable
|
|
(described below), for the reasons described in
|
|
.BR prctl (2).
|
|
.RE
|
|
.IP
|
|
Resetting the "dumpable" attribute to 1 reverts the ownership of the
|
|
.IR /proc/[pid]/*
|
|
files to the process's effective UID and GID.
|
|
Note, however, that if the effective UID or GID is subsequently modified,
|
|
then the "dumpable" attribute may be reset, as described in
|
|
.BR prctl (2).
|
|
Therefore, it may be desirable to reset the "dumpable" attribute
|
|
.I after
|
|
making any desired changes to the process's effective UID or GID.
|
|
.TP
|
|
.I /proc/[pid]/attr
|
|
.\" https://lwn.net/Articles/28222/
|
|
.\" From: Stephen Smalley <sds@epoch.ncsc.mil>
|
|
.\" To: LKML and others
|
|
.\" Subject: [RFC][PATCH] Process Attribute API for Security Modules
|
|
.\" Date: 08 Apr 2003 16:17:52 -0400
|
|
.\"
|
|
.\" http://www.nsa.gov/research/_files/selinux/papers/module/x362.shtml
|
|
.\"
|
|
The files in this directory provide an API for security modules.
|
|
The contents of this directory are files that can be read and written
|
|
in order to set security-related attributes.
|
|
This directory was added to support SELinux,
|
|
but the intention was that the API be general enough to support
|
|
other security modules.
|
|
For the purpose of explanation,
|
|
examples of how SELinux uses these files are provided below.
|
|
.IP
|
|
This directory is present only if the kernel was configured with
|
|
.BR CONFIG_SECURITY .
|
|
.TP
|
|
.IR /proc/[pid]/attr/current " (since Linux 2.6.0)"
|
|
The contents of this file represent the current
|
|
security attributes of the process.
|
|
.IP
|
|
In SELinux, this file is used to get the security context of a process.
|
|
Prior to Linux 2.6.11, this file could not be used to set the security
|
|
context (a write was always denied), since SELinux limited process security
|
|
transitions to
|
|
.BR execve (2)
|
|
(see the description of
|
|
.IR /proc/[pid]/attr/exec ,
|
|
below).
|
|
Since Linux 2.6.11, SELinux lifted this restriction and began supporting
|
|
"set" operations via writes to this node if authorized by policy,
|
|
although use of this operation is only suitable for applications that are
|
|
trusted to maintain any desired separation between the old and new security
|
|
contexts.
|
|
.IP
|
|
Prior to Linux 2.6.28, SELinux did not allow threads within a
|
|
multithreaded process to set their security context via this node
|
|
as it would yield an inconsistency among the security contexts of the
|
|
threads sharing the same memory space.
|
|
Since Linux 2.6.28, SELinux lifted
|
|
this restriction and began supporting "set" operations for threads within
|
|
a multithreaded process if the new security context is bounded by the old
|
|
security context, where the bounded relation is defined in policy and
|
|
guarantees that the new security context has a subset of the permissions
|
|
of the old security context.
|
|
.IP
|
|
Other security modules may choose to support "set" operations via
|
|
writes to this node.
|
|
.TP
|
|
.IR /proc/[pid]/attr/exec " (since Linux 2.6.0)"
|
|
This file represents the attributes to assign to the
|
|
process upon a subsequent
|
|
.BR execve (2).
|
|
.IP
|
|
In SELinux,
|
|
this is needed to support role/domain transitions, and
|
|
.BR execve (2)
|
|
is the preferred point to make such transitions because it offers better
|
|
control over the initialization of the process in the new security label
|
|
and the inheritance of state.
|
|
In SELinux, this attribute is reset on
|
|
.BR execve (2)
|
|
so that the new program reverts to the default behavior for any
|
|
.BR execve (2)
|
|
calls that it may make.
|
|
In SELinux, a process can set
|
|
only its own
|
|
.I /proc/[pid]/attr/exec
|
|
attribute.
|
|
.TP
|
|
.IR /proc/[pid]/attr/fscreate " (since Linux 2.6.0)"
|
|
This file represents the attributes to assign to files
|
|
created by subsequent calls to
|
|
.BR open (2),
|
|
.BR mkdir (2),
|
|
.BR symlink (2),
|
|
and
|
|
.BR mknod (2)
|
|
.IP
|
|
SELinux employs this file to support creation of a file
|
|
(using the aforementioned system calls)
|
|
in a secure state,
|
|
so that there is no risk of inappropriate access being obtained
|
|
between the time of creation and the time that attributes are set.
|
|
In SELinux, this attribute is reset on
|
|
.BR execve (2),
|
|
so that the new program reverts to the default behavior for
|
|
any file creation calls it may make, but the attribute will persist
|
|
across multiple file creation calls within a program unless it is
|
|
explicitly reset.
|
|
In SELinux, a process can set only its own
|
|
.IR /proc/[pid]/attr/fscreate
|
|
attribute.
|
|
.TP
|
|
.IR /proc/[pid]/attr/keycreate " (since Linux 2.6.18)"
|
|
.\" commit 4eb582cf1fbd7b9e5f466e3718a59c957e75254e
|
|
If a process writes a security context into this file,
|
|
all subsequently created keys
|
|
.RB ( add_key (2))
|
|
will be labeled with this context.
|
|
For further information, see the kernel source file
|
|
.I Documentation/security/keys/core.rst
|
|
(or file
|
|
.\" commit b68101a1e8f0263dbc7b8375d2a7c57c6216fb76
|
|
.I Documentation/security/keys.txt
|
|
on Linux between 3.0 and 4.13, or
|
|
.\" commit d410fa4ef99112386de5f218dd7df7b4fca910b4
|
|
.I Documentation/keys.txt
|
|
before Linux 3.0).
|
|
.TP
|
|
.IR /proc/[pid]/attr/prev " (since Linux 2.6.0)"
|
|
This file contains the security context of the process before the last
|
|
.BR execve (2);
|
|
that is, the previous value of
|
|
.IR /proc/[pid]/attr/current .
|
|
.TP
|
|
.IR /proc/[pid]/attr/socketcreate " (since Linux 2.6.18)"
|
|
.\" commit 42c3e03ef6b298813557cdb997bd6db619cd65a2
|
|
If a process writes a security context into this file,
|
|
all subsequently created sockets will be labeled with this context.
|
|
.TP
|
|
.IR /proc/[pid]/autogroup " (since Linux 2.6.38)"
|
|
.\" commit 5091faa449ee0b7d73bc296a93bca9540fc51d0a
|
|
See
|
|
.BR sched (7).
|
|
.TP
|
|
.IR /proc/[pid]/auxv " (since 2.6.0)"
|
|
.\" Precisely: Linux 2.6.0-test7
|
|
This contains the contents of the ELF interpreter information passed
|
|
to the process at exec time.
|
|
The format is one \fIunsigned long\fP ID
|
|
plus one \fIunsigned long\fP value for each entry.
|
|
The last entry contains two zeros.
|
|
See also
|
|
.BR getauxval (3).
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[pid]/cgroup " (since Linux 2.6.24)"
|
|
See
|
|
.BR cgroups (7).
|
|
.TP
|
|
.IR /proc/[pid]/clear_refs " (since Linux 2.6.22)"
|
|
.\" commit b813e931b4c8235bb42e301096ea97dbdee3e8fe (2.6.22)
|
|
.\" commit 398499d5f3613c47f2143b8c54a04efb5d7a6da9 (2.6.32)
|
|
.\" commit 040fa02077de01c7e08fa75be6125e4ca5636011 (3.11)
|
|
.\"
|
|
.\" "Clears page referenced bits shown in smaps output"
|
|
.\" write-only, writable only by the owner of the process
|
|
.IP
|
|
This is a write-only file, writable only by owner of the process.
|
|
.IP
|
|
The following values may be written to the file:
|
|
.RS
|
|
.TP
|
|
1 (since Linux 2.6.22)
|
|
.\" Internally: CLEAR_REFS_ALL
|
|
Reset the PG_Referenced and ACCESSED/YOUNG
|
|
bits for all the pages associated with the process.
|
|
(Before kernel 2.6.32, writing any nonzero value to this file
|
|
had this effect.)
|
|
.TP
|
|
2 (since Linux 2.6.32)
|
|
.\" Internally: CLEAR_REFS_ANON
|
|
Reset the PG_Referenced and ACCESSED/YOUNG
|
|
bits for all anonymous pages associated with the process.
|
|
.TP
|
|
3 (since Linux 2.6.32)
|
|
.\" Internally: CLEAR_REFS_MAPPED
|
|
Reset the PG_Referenced and ACCESSED/YOUNG
|
|
bits for all file-mapped pages associated with the process.
|
|
.RE
|
|
.IP
|
|
Clearing the PG_Referenced and ACCESSED/YOUNG bits provides a method
|
|
to measure approximately how much memory a process is using.
|
|
One first inspects the values in the "Referenced" fields
|
|
for the VMAs shown in
|
|
.IR /proc/[pid]/smaps
|
|
to get an idea of the memory footprint of the
|
|
process.
|
|
One then clears the PG_Referenced and ACCESSED/YOUNG bits
|
|
and, after some measured time interval,
|
|
once again inspects the values in the "Referenced" fields
|
|
to get an idea of the change in memory footprint of the
|
|
process during the measured interval.
|
|
If one is interested only in inspecting the selected mapping types,
|
|
then the value 2 or 3 can be used instead of 1.
|
|
.IP
|
|
Further values can be written to affect different properties:
|
|
.RS
|
|
.TP
|
|
4 (since Linux 3.11)
|
|
Clear the soft-dirty bit for all the pages associated with the process.
|
|
.\" Internally: CLEAR_REFS_SOFT_DIRTY
|
|
This is used (in conjunction with
|
|
.IR /proc/[pid]/pagemap )
|
|
by the check-point restore system to discover which pages of a process
|
|
have been dirtied since the file
|
|
.IR /proc/[pid]/clear_refs
|
|
was written to.
|
|
.TP
|
|
5 (since Linux 4.0)
|
|
.\" Internally: CLEAR_REFS_MM_HIWATER_RSS
|
|
Reset the peak resident set size ("high water mark") to the process's
|
|
current resident set size value.
|
|
.RE
|
|
.IP
|
|
Writing any value to
|
|
.IR /proc/[pid]/clear_refs
|
|
other than those listed above has no effect.
|
|
.IP
|
|
The
|
|
.IR /proc/[pid]/clear_refs
|
|
file is present only if the
|
|
.B CONFIG_PROC_PAGE_MONITOR
|
|
kernel configuration option is enabled.
|
|
.TP
|
|
.I /proc/[pid]/cmdline
|
|
This read-only file holds the complete command line for the process,
|
|
unless the process is a zombie.
|
|
.\" In 2.3.26, this also used to be true if the process was swapped out.
|
|
In the latter case, there is nothing in this file:
|
|
that is, a read on this file will return 0 characters.
|
|
The command-line arguments appear in this file as a set of
|
|
strings separated by null bytes (\(aq\e0\(aq),
|
|
with a further null byte after the last string.
|
|
.IP
|
|
If, after an
|
|
.BR execve (2),
|
|
the process modifies its
|
|
.I argv
|
|
strings, those changes will show up here.
|
|
This is not the same thing as modifying the
|
|
.I argv
|
|
array.
|
|
.IP
|
|
Furthermore, a process may change the memory location that this file refers via
|
|
.BR prctl (2)
|
|
operations such as
|
|
.BR PR_SET_MM_ARG_START .
|
|
.IP
|
|
Think of this file as the command line that the process wants you to see.
|
|
.TP
|
|
.IR /proc/[pid]/comm " (since Linux 2.6.33)"
|
|
.\" commit 4614a696bd1c3a9af3a08f0e5874830a85b889d4
|
|
This file exposes the process's
|
|
.I comm
|
|
value\(emthat is, the command name associated with the process.
|
|
Different threads in the same process may have different
|
|
.I comm
|
|
values, accessible via
|
|
.IR /proc/[pid]/task/[tid]/comm .
|
|
A thread may modify its
|
|
.I comm
|
|
value, or that of any of other thread in the same thread group (see
|
|
the discussion of
|
|
.B CLONE_THREAD
|
|
in
|
|
.BR clone (2)),
|
|
by writing to the file
|
|
.IR /proc/self/task/[tid]/comm .
|
|
Strings longer than
|
|
.B TASK_COMM_LEN
|
|
(16) characters (including the terminating null byte) are silently truncated.
|
|
.IP
|
|
This file provides a superset of the
|
|
.BR prctl (2)
|
|
.B PR_SET_NAME
|
|
and
|
|
.B PR_GET_NAME
|
|
operations, and is employed by
|
|
.BR pthread_setname_np (3)
|
|
when used to rename threads other than the caller.
|
|
The value in this file is used for the
|
|
.I %e
|
|
specifier in
|
|
.IR /proc/sys/kernel/core_pattern ;
|
|
see
|
|
.BR core (5).
|
|
.TP
|
|
.IR /proc/[pid]/coredump_filter " (since Linux 2.6.23)"
|
|
See
|
|
.BR core (5).
|
|
.TP
|
|
.IR /proc/[pid]/cpuset " (since Linux 2.6.12)"
|
|
.\" and/proc/[pid]/task/[tid]/cpuset
|
|
See
|
|
.BR cpuset (7).
|
|
.TP
|
|
.I /proc/[pid]/cwd
|
|
This is a symbolic link to the current working directory of the process.
|
|
To find out the current working directory of process 20,
|
|
for instance, you can do this:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " cd /proc/20/cwd; pwd \-P"
|
|
.EE
|
|
.in
|
|
.IP
|
|
.\" The following was still true as at kernel 2.6.13
|
|
In a multithreaded process, the contents of this symbolic link
|
|
are not available if the main thread has already terminated
|
|
(typically by calling
|
|
.BR pthread_exit (3)).
|
|
.IP
|
|
Permission to dereference or read
|
|
.RB ( readlink (2))
|
|
this symbolic link is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.I /proc/[pid]/environ
|
|
This file contains the initial environment that was set
|
|
when the currently executing program was started via
|
|
.BR execve (2).
|
|
The entries are separated by null bytes (\(aq\e0\(aq),
|
|
and there may be a null byte at the end.
|
|
Thus, to print out the environment of process 1, you would do:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " cat /proc/1/environ | tr \(aq\e000\(aq \(aq\en\(aq"
|
|
.EE
|
|
.in
|
|
.IP
|
|
If, after an
|
|
.BR execve (2),
|
|
the process modifies its environment
|
|
(e.g., by calling functions such as
|
|
.BR putenv (3)
|
|
or modifying the
|
|
.BR environ (7)
|
|
variable directly),
|
|
this file will
|
|
.I not
|
|
reflect those changes.
|
|
.IP
|
|
Furthermore, a process may change the memory location that this file refers via
|
|
.BR prctl (2)
|
|
operations such as
|
|
.BR PR_SET_MM_ENV_START .
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.I /proc/[pid]/exe
|
|
Under Linux 2.2 and later, this file is a symbolic link
|
|
containing the actual pathname of the executed command.
|
|
This symbolic link can be dereferenced normally; attempting to open
|
|
it will open the executable.
|
|
You can even type
|
|
.I /proc/[pid]/exe
|
|
to run another copy of the same executable that is being run by
|
|
process [pid].
|
|
If the pathname has been unlinked, the symbolic link will contain the
|
|
string \(aq(deleted)\(aq appended to the original pathname.
|
|
.\" The following was still true as at kernel 2.6.13
|
|
In a multithreaded process, the contents of this symbolic link
|
|
are not available if the main thread has already terminated
|
|
(typically by calling
|
|
.BR pthread_exit (3)).
|
|
.IP
|
|
Permission to dereference or read
|
|
.RB ( readlink (2))
|
|
this symbolic link is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.IP
|
|
Under Linux 2.0 and earlier,
|
|
.I /proc/[pid]/exe
|
|
is a pointer to the binary which was executed,
|
|
and appears as a symbolic link.
|
|
A
|
|
.BR readlink (2)
|
|
call on this file under Linux 2.0 returns a string in the format:
|
|
.IP
|
|
[device]:inode
|
|
.IP
|
|
For example, [0301]:1502 would be inode 1502 on device major 03 (IDE,
|
|
MFM, etc. drives) minor 01 (first partition on the first drive).
|
|
.IP
|
|
.BR find (1)
|
|
with the
|
|
.I \-inum
|
|
option can be used to locate the file.
|
|
.TP
|
|
.I /proc/[pid]/fd/
|
|
This is a subdirectory containing one entry for each file which the
|
|
process has open, named by its file descriptor, and which is a
|
|
symbolic link to the actual file.
|
|
Thus, 0 is standard input, 1 standard output, 2 standard error, and so on.
|
|
.IP
|
|
For file descriptors for pipes and sockets,
|
|
the entries will be symbolic links whose content is the
|
|
file type with the inode.
|
|
A
|
|
.BR readlink (2)
|
|
call on this file returns a string in the format:
|
|
.IP
|
|
type:[inode]
|
|
.IP
|
|
For example,
|
|
.I socket:[2248868]
|
|
will be a socket and its inode is 2248868.
|
|
For sockets, that inode can be used to find more information
|
|
in one of the files under
|
|
.IR /proc/net/ .
|
|
.IP
|
|
For file descriptors that have no corresponding inode
|
|
(e.g., file descriptors produced by
|
|
.BR bpf (2),
|
|
.BR epoll_create (2),
|
|
.BR eventfd (2),
|
|
.BR inotify_init (2),
|
|
.BR perf_event_open (2),
|
|
.BR signalfd (2),
|
|
.BR timerfd_create (2),
|
|
and
|
|
.BR userfaultfd (2)),
|
|
the entry will be a symbolic link with contents of the form
|
|
.IP
|
|
anon_inode:<file-type>
|
|
.IP
|
|
In many cases (but not all), the
|
|
.I file-type
|
|
is surrounded by square brackets.
|
|
.IP
|
|
For example, an epoll file descriptor will have a symbolic link
|
|
whose content is the string
|
|
.IR "anon_inode:[eventpoll]" .
|
|
.IP
|
|
.\"The following was still true as at kernel 2.6.13
|
|
In a multithreaded process, the contents of this directory
|
|
are not available if the main thread has already terminated
|
|
(typically by calling
|
|
.BR pthread_exit (3)).
|
|
.IP
|
|
Programs that take a filename as a command-line argument,
|
|
but don't take input from standard input if no argument is supplied,
|
|
and programs that write to a file named as a command-line argument,
|
|
but don't send their output to standard output
|
|
if no argument is supplied, can nevertheless be made to use
|
|
standard input or standard output by using
|
|
.IR /proc/[pid]/fd
|
|
files as command-line arguments.
|
|
For example, assuming that
|
|
.I \-i
|
|
is the flag designating an input file and
|
|
.I \-o
|
|
is the flag designating an output file:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " foobar \-i /proc/self/fd/0 \-o /proc/self/fd/1 ..."
|
|
.EE
|
|
.in
|
|
.IP
|
|
and you have a working filter.
|
|
.\" The following is not true in my tests (MTK):
|
|
.\" Note that this will not work for
|
|
.\" programs that seek on their files, as the files in the fd directory
|
|
.\" are not seekable.
|
|
.IP
|
|
.I /proc/self/fd/N
|
|
is approximately the same as
|
|
.I /dev/fd/N
|
|
in some UNIX and UNIX-like systems.
|
|
Most Linux MAKEDEV scripts symbolically link
|
|
.I /dev/fd
|
|
to
|
|
.IR /proc/self/fd ,
|
|
in fact.
|
|
.IP
|
|
Most systems provide symbolic links
|
|
.IR /dev/stdin ,
|
|
.IR /dev/stdout ,
|
|
and
|
|
.IR /dev/stderr ,
|
|
which respectively link to the files
|
|
.IR 0 ,
|
|
.IR 1 ,
|
|
and
|
|
.IR 2
|
|
in
|
|
.IR /proc/self/fd .
|
|
Thus the example command above could be written as:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..."
|
|
.EE
|
|
.in
|
|
.IP
|
|
Permission to dereference or read
|
|
.RB ( readlink (2))
|
|
the symbolic links in this directory is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.IP
|
|
Note that for file descriptors referring to inodes (pipes and sockets, see above),
|
|
those inodes still have permission bits and ownership information
|
|
distinct from those of the
|
|
.I /proc/[pid]/fd
|
|
entry,
|
|
and that the owner may differ from the user and group IDs of the process.
|
|
An unprivileged process may lack permissions to open them, as in this example:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " echo test | sudo \-u nobody cat"
|
|
test
|
|
.RB "$" " echo test | sudo \-u nobody cat /proc/self/fd/0"
|
|
cat: /proc/self/fd/0: Permission denied
|
|
.EE
|
|
.in
|
|
.IP
|
|
File descriptor 0 refers to the pipe created by the shell
|
|
and owned by that shell's user, which is not
|
|
.IR nobody ,
|
|
so
|
|
.B cat
|
|
does not have permission to create a new file descriptor to read from that inode,
|
|
even though it can still read from its existing file descriptor 0.
|
|
.TP
|
|
.IR /proc/[pid]/fdinfo/ " (since Linux 2.6.22)"
|
|
This is a subdirectory containing one entry for each file which the
|
|
process has open, named by its file descriptor.
|
|
The files in this directory are readable only by the owner of the process.
|
|
The contents of each file can be read to obtain information
|
|
about the corresponding file descriptor.
|
|
The content depends on the type of file referred to by the
|
|
corresponding file descriptor.
|
|
.IP
|
|
For regular files and directories, we see something like:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " cat /proc/12015/fdinfo/4"
|
|
pos: 1000
|
|
flags: 01002002
|
|
mnt_id: 21
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields are as follows:
|
|
.RS
|
|
.TP
|
|
.I pos
|
|
This is a decimal number showing the file offset.
|
|
.TP
|
|
.I flags
|
|
This is an octal number that displays the
|
|
file access mode and file status flags (see
|
|
.BR open (2)).
|
|
If the close-on-exec file descriptor flag is set, then
|
|
.I flags
|
|
will also include the value
|
|
.BR O_CLOEXEC .
|
|
.IP
|
|
Before Linux 3.1,
|
|
.\" commit 1117f72ea0217ba0cc19f05adbbd8b9a397f5ab7
|
|
this field incorrectly displayed the setting of
|
|
.B O_CLOEXEC
|
|
at the time the file was opened,
|
|
rather than the current setting of the close-on-exec flag.
|
|
.TP
|
|
.I
|
|
.I mnt_id
|
|
This field, present since Linux 3.15,
|
|
.\" commit 49d063cb353265c3af701bab215ac438ca7df36d
|
|
is the ID of the mount containing this file.
|
|
See the description of
|
|
.IR /proc/[pid]/mountinfo .
|
|
.RE
|
|
.IP
|
|
For eventfd file descriptors (see
|
|
.BR eventfd (2)),
|
|
we see (since Linux 3.8)
|
|
.\" commit cbac5542d48127b546a23d816380a7926eee1c25
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 02
|
|
mnt_id: 10
|
|
eventfd\-count: 40
|
|
.EE
|
|
.in
|
|
.IP
|
|
.I eventfd\-count
|
|
is the current value of the eventfd counter, in hexadecimal.
|
|
.IP
|
|
For epoll file descriptors (see
|
|
.BR epoll (7)),
|
|
we see (since Linux 3.8)
|
|
.\" commit 138d22b58696c506799f8de759804083ff9effae
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 02
|
|
mnt_id: 10
|
|
tfd: 9 events: 19 data: 74253d2500000009
|
|
tfd: 7 events: 19 data: 74253d2500000007
|
|
.EE
|
|
.in
|
|
.IP
|
|
Each of the lines beginning
|
|
.I tfd
|
|
describes one of the file descriptors being monitored via
|
|
the epoll file descriptor (see
|
|
.BR epoll_ctl (2)
|
|
for some details).
|
|
The
|
|
.IR tfd
|
|
field is the number of the file descriptor.
|
|
The
|
|
.I events
|
|
field is a hexadecimal mask of the events being monitored for this file
|
|
descriptor.
|
|
The
|
|
.I data
|
|
field is the data value associated with this file descriptor.
|
|
.IP
|
|
For signalfd file descriptors (see
|
|
.BR signalfd (2)),
|
|
we see (since Linux 3.8)
|
|
.\" commit 138d22b58696c506799f8de759804083ff9effae
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 02
|
|
mnt_id: 10
|
|
sigmask: 0000000000000006
|
|
.EE
|
|
.in
|
|
.IP
|
|
.I sigmask
|
|
is the hexadecimal mask of signals that are accepted via this
|
|
signalfd file descriptor.
|
|
(In this example, bits 2 and 3 are set, corresponding to the signals
|
|
.B SIGINT
|
|
and
|
|
.BR SIGQUIT ;
|
|
see
|
|
.BR signal (7).)
|
|
.IP
|
|
For inotify file descriptors (see
|
|
.BR inotify (7)),
|
|
we see (since Linux 3.8)
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 00
|
|
mnt_id: 11
|
|
inotify wd:2 ino:7ef82a sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:2af87e00220ffd73
|
|
inotify wd:1 ino:192627 sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:27261900802dfd73
|
|
.EE
|
|
.in
|
|
.IP
|
|
Each of the lines beginning with "inotify" displays information about
|
|
one file or directory that is being monitored.
|
|
The fields in this line are as follows:
|
|
.RS
|
|
.TP
|
|
.I wd
|
|
A watch descriptor number (in decimal).
|
|
.TP
|
|
.I ino
|
|
The inode number of the target file (in hexadecimal).
|
|
.TP
|
|
.I sdev
|
|
The ID of the device where the target file resides (in hexadecimal).
|
|
.TP
|
|
.I mask
|
|
The mask of events being monitored for the target file (in hexadecimal).
|
|
.RE
|
|
.IP
|
|
If the kernel was built with exportfs support, the path to the target
|
|
file is exposed as a file handle, via three hexadecimal fields:
|
|
.IR fhandle\-bytes ,
|
|
.IR fhandle\-type ,
|
|
and
|
|
.IR f_handle .
|
|
.IP
|
|
For fanotify file descriptors (see
|
|
.BR fanotify (7)),
|
|
we see (since Linux 3.8)
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 02
|
|
mnt_id: 11
|
|
fanotify flags:0 event\-flags:88002
|
|
fanotify ino:19264f sdev:800001 mflags:0 mask:1 ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:4f261900a82dfd73
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fourth line displays information defined when the fanotify group
|
|
was created via
|
|
.BR fanotify_init (2):
|
|
.RS
|
|
.TP
|
|
.I flags
|
|
The
|
|
.I flags
|
|
argument given to
|
|
.BR fanotify_init (2)
|
|
(expressed in hexadecimal).
|
|
.TP
|
|
.I event\-flags
|
|
The
|
|
.I event_f_flags
|
|
argument given to
|
|
.BR fanotify_init (2)
|
|
(expressed in hexadecimal).
|
|
.RE
|
|
.IP
|
|
Each additional line shown in the file contains information
|
|
about one of the marks in the fanotify group.
|
|
Most of these fields are as for inotify, except:
|
|
.RS
|
|
.TP
|
|
.I mflags
|
|
The flags associated with the mark
|
|
(expressed in hexadecimal).
|
|
.TP
|
|
.I mask
|
|
The events mask for this mark
|
|
(expressed in hexadecimal).
|
|
.TP
|
|
.I ignored_mask
|
|
The mask of events that are ignored for this mark
|
|
(expressed in hexadecimal).
|
|
.RE
|
|
.IP
|
|
For details on these fields, see
|
|
.BR fanotify_mark (2).
|
|
.IP
|
|
For timerfd file descriptors (see
|
|
.BR timerfd (2)),
|
|
we see (since Linux 3.17)
|
|
.\" commit af9c4957cf212ad9cf0bee34c95cb11de5426e85
|
|
the following fields:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
pos: 0
|
|
flags: 02004002
|
|
mnt_id: 13
|
|
clockid: 0
|
|
ticks: 0
|
|
settime flags: 03
|
|
it_value: (7695568592, 640020877)
|
|
it_interval: (0, 0)
|
|
.EE
|
|
.in
|
|
.RS
|
|
.TP
|
|
.I clockid
|
|
This is the numeric value of the clock ID
|
|
(corresponding to one of the
|
|
.B CLOCK_*
|
|
constants defined via
|
|
.IR <time.h> )
|
|
that is used to mark the progress of the timer (in this example, 0 is
|
|
.BR CLOCK_REALTIME ).
|
|
.TP
|
|
.I ticks
|
|
This is the number of timer expirations that have occurred,
|
|
(i.e., the value that
|
|
.BR read (2)
|
|
on it would return).
|
|
.TP
|
|
.I settime flags
|
|
This field lists the flags with which the timerfd was last armed (see
|
|
.BR timerfd_settime (2)),
|
|
in octal
|
|
(in this example, both
|
|
.B TFD_TIMER_ABSTIME
|
|
and
|
|
.B TFD_TIMER_CANCEL_ON_SET
|
|
are set).
|
|
.TP
|
|
.I it_value
|
|
This field contains the amount of time until the timer will next expire,
|
|
expressed in seconds and nanoseconds.
|
|
This is always expressed as a relative value,
|
|
regardless of whether the timer was created using the
|
|
.B TFD_TIMER_ABSTIME
|
|
flag.
|
|
.TP
|
|
.I it_interval
|
|
This field contains the interval of the timer,
|
|
in seconds and nanoseconds.
|
|
(The
|
|
.I it_value
|
|
and
|
|
.I it_interval
|
|
fields contain the values that
|
|
.BR timerfd_gettime (2)
|
|
on this file descriptor would return.)
|
|
.RE
|
|
.TP
|
|
.IR /proc/[pid]/gid_map " (since Linux 3.5)"
|
|
See
|
|
.BR user_namespaces (7).
|
|
.TP
|
|
.IR /proc/[pid]/io " (since kernel 2.6.20)"
|
|
.\" commit 7c3ab7381e79dfc7db14a67c6f4f3285664e1ec2
|
|
This file contains I/O statistics for the process, for example:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "#" " cat /proc/3828/io"
|
|
rchar: 323934931
|
|
wchar: 323929600
|
|
syscr: 632687
|
|
syscw: 632675
|
|
read_bytes: 0
|
|
write_bytes: 323932160
|
|
cancelled_write_bytes: 0
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields are as follows:
|
|
.RS
|
|
.TP
|
|
.IR rchar ": characters read"
|
|
The number of bytes which this task has caused to be read from storage.
|
|
This is simply the sum of bytes which this process passed to
|
|
.BR read (2)
|
|
and similar system calls.
|
|
It includes things such as terminal I/O and
|
|
is unaffected by whether or not actual
|
|
physical disk I/O was required (the read might have been satisfied from
|
|
pagecache).
|
|
.TP
|
|
.IR wchar ": characters written"
|
|
The number of bytes which this task has caused, or shall cause to be written
|
|
to disk.
|
|
Similar caveats apply here as with
|
|
.IR rchar .
|
|
.TP
|
|
.IR syscr ": read syscalls"
|
|
Attempt to count the number of read I/O operations\(emthat is,
|
|
system calls such as
|
|
.BR read (2)
|
|
and
|
|
.BR pread (2).
|
|
.TP
|
|
.IR syscw ": write syscalls"
|
|
Attempt to count the number of write I/O operations\(emthat is,
|
|
system calls such as
|
|
.BR write (2)
|
|
and
|
|
.BR pwrite (2).
|
|
.TP
|
|
.IR read_bytes ": bytes read"
|
|
Attempt to count the number of bytes which this process really did cause to
|
|
be fetched from the storage layer.
|
|
This is accurate for block-backed filesystems.
|
|
.TP
|
|
.IR write_bytes ": bytes written"
|
|
Attempt to count the number of bytes which this process caused to be sent to
|
|
the storage layer.
|
|
.TP
|
|
.IR cancelled_write_bytes :
|
|
The big inaccuracy here is truncate.
|
|
If a process writes 1 MB to a file and then deletes the file,
|
|
it will in fact perform no writeout.
|
|
But it will have been accounted as having caused 1 MB of write.
|
|
In other words: this field represents the number of bytes which this process
|
|
caused to not happen, by truncating pagecache.
|
|
A task can cause "negative" I/O too.
|
|
If this task truncates some dirty pagecache,
|
|
some I/O which another task has been accounted for
|
|
(in its
|
|
.IR write_bytes )
|
|
will not be happening.
|
|
.RE
|
|
.IP
|
|
.IR Note :
|
|
In the current implementation, things are a bit racy on 32-bit systems:
|
|
if process A reads process B's
|
|
.I /proc/[pid]/io
|
|
while process B is updating one of these 64-bit counters,
|
|
process A could see an intermediate result.
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[pid]/limits " (since Linux 2.6.24)"
|
|
This file displays the soft limit, hard limit, and units of measurement
|
|
for each of the process's resource limits (see
|
|
.BR getrlimit (2)).
|
|
Up to and including Linux 2.6.35,
|
|
this file is protected to allow reading only by the real UID of the process.
|
|
Since Linux 2.6.36,
|
|
.\" commit 3036e7b490bf7878c6dae952eec5fb87b1106589
|
|
this file is readable by all users on the system.
|
|
.\" FIXME Describe /proc/[pid]/loginuid
|
|
.\" Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
|
|
.\" CONFIG_AUDITSYSCALL
|
|
.TP
|
|
.IR /proc/[pid]/map_files/ " (since kernel 3.3)"
|
|
.\" commit 640708a2cff7f81e246243b0073c66e6ece7e53e
|
|
This subdirectory contains entries corresponding to memory-mapped
|
|
files (see
|
|
.BR mmap (2)).
|
|
Entries are named by memory region start and end
|
|
address pair (expressed as hexadecimal numbers),
|
|
and are symbolic links to the mapped files themselves.
|
|
Here is an example, with the output wrapped and reformatted to fit on an 80-column display:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "#" " ls \-l /proc/self/map_files/"
|
|
lr\-\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:31
|
|
3252e00000\-3252e20000 \-> /usr/lib64/ld\-2.15.so
|
|
\&...
|
|
.EE
|
|
.in
|
|
.IP
|
|
Although these entries are present for memory regions that were
|
|
mapped with the
|
|
.BR MAP_FILE
|
|
flag, the way anonymous shared memory (regions created with the
|
|
.B MAP_ANON | MAP_SHARED
|
|
flags)
|
|
is implemented in Linux
|
|
means that such regions also appear on this directory.
|
|
Here is an example where the target file is the deleted
|
|
.I /dev/zero
|
|
one:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
lrw\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:33
|
|
7fc075d2f000\-7fc075e6f000 \-> /dev/zero (deleted)
|
|
.EE
|
|
.in
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.IP
|
|
Until kernel version 4.3,
|
|
.\" commit bdb4d100afe9818aebd1d98ced575c5ef143456c
|
|
this directory appeared only if the
|
|
.B CONFIG_CHECKPOINT_RESTORE
|
|
kernel configuration option was enabled.
|
|
.IP
|
|
Capabilities are required to read the contents of the symbolic links in
|
|
this directory: before Linux 5.9, the reading process requires
|
|
.BR CAP_SYS_ADMIN
|
|
in the initial user namespace;
|
|
since Linux 5.9, the reading process must have either
|
|
.BR CAP_SYS_ADMIN
|
|
or
|
|
.BR CAP_CHECKPOINT_RESTORE
|
|
in the user namespace where it resides.
|
|
.TP
|
|
.I /proc/[pid]/maps
|
|
A file containing the currently mapped memory regions and their access
|
|
permissions.
|
|
See
|
|
.BR mmap (2)
|
|
for some further information about memory mappings.
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.IP
|
|
The format of the file is:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.I "address perms offset dev inode pathname"
|
|
00400000\-00452000 r\-xp 00000000 08:02 173521 /usr/bin/dbus\-daemon
|
|
00651000\-00652000 r\-\-p 00051000 08:02 173521 /usr/bin/dbus\-daemon
|
|
00652000\-00655000 rw\-p 00052000 08:02 173521 /usr/bin/dbus\-daemon
|
|
00e03000\-00e24000 rw\-p 00000000 00:00 0 [heap]
|
|
00e24000\-011f7000 rw\-p 00000000 00:00 0 [heap]
|
|
\&...
|
|
35b1800000\-35b1820000 r\-xp 00000000 08:02 135522 /usr/lib64/ld\-2.15.so
|
|
35b1a1f000\-35b1a20000 r\-\-p 0001f000 08:02 135522 /usr/lib64/ld\-2.15.so
|
|
35b1a20000\-35b1a21000 rw\-p 00020000 08:02 135522 /usr/lib64/ld\-2.15.so
|
|
35b1a21000\-35b1a22000 rw\-p 00000000 00:00 0
|
|
35b1c00000\-35b1dac000 r\-xp 00000000 08:02 135870 /usr/lib64/libc\-2.15.so
|
|
35b1dac000\-35b1fac000 \-\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so
|
|
35b1fac000\-35b1fb0000 r\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so
|
|
35b1fb0000\-35b1fb2000 rw\-p 001b0000 08:02 135870 /usr/lib64/libc\-2.15.so
|
|
\&...
|
|
f2c6ff8c000\-7f2c7078c000 rw\-p 00000000 00:00 0 [stack:986]
|
|
\&...
|
|
7fffb2c0d000\-7fffb2c2e000 rw\-p 00000000 00:00 0 [stack]
|
|
7fffb2d48000\-7fffb2d49000 r\-xp 00000000 00:00 0 [vdso]
|
|
.EE
|
|
.in
|
|
.IP
|
|
The
|
|
.I address
|
|
field is the address space in the process that the mapping occupies.
|
|
The
|
|
.I perms
|
|
field is a set of permissions:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
r = read
|
|
w = write
|
|
x = execute
|
|
s = shared
|
|
p = private (copy on write)
|
|
.EE
|
|
.in
|
|
.IP
|
|
The
|
|
.I offset
|
|
field is the offset into the file/whatever;
|
|
.I dev
|
|
is the device
|
|
(major:minor);
|
|
.I inode
|
|
is the inode on that device.
|
|
0 indicates that no inode is associated with the memory region,
|
|
as would be the case with BSS (uninitialized data).
|
|
.IP
|
|
The
|
|
.I pathname
|
|
field will usually be the file that is backing the mapping.
|
|
For ELF files,
|
|
you can easily coordinate with the
|
|
.I offset
|
|
field by looking at the
|
|
Offset field in the ELF program headers
|
|
.RI ( "readelf\ \-l" ).
|
|
.IP
|
|
There are additional helpful pseudo-paths:
|
|
.RS
|
|
.TP
|
|
.IR [stack]
|
|
The initial process's (also known as the main thread's) stack.
|
|
.TP
|
|
.IR [stack:<tid>] " (from Linux 3.4 to 4.4)"
|
|
.\" commit b76437579d1344b612cf1851ae610c636cec7db0 (added)
|
|
.\" commit 65376df582174ffcec9e6471bf5b0dd79ba05e4a (removed)
|
|
A thread's stack (where the
|
|
.IR <tid>
|
|
is a thread ID).
|
|
It corresponds to the
|
|
.IR /proc/[pid]/task/[tid]/
|
|
path.
|
|
This field was removed in Linux 4.5, since providing this information
|
|
for a process with large numbers of threads is expensive.
|
|
.TP
|
|
.IR [vdso]
|
|
The virtual dynamically linked shared object.
|
|
See
|
|
.BR vdso (7).
|
|
.TP
|
|
.IR [heap]
|
|
The process's heap.
|
|
.in
|
|
.RE
|
|
.IP
|
|
If the
|
|
.I pathname
|
|
field is blank,
|
|
this is an anonymous mapping as obtained via
|
|
.BR mmap (2).
|
|
There is no easy way to coordinate this back to a process's source,
|
|
short of running it through
|
|
.BR gdb (1),
|
|
.BR strace (1),
|
|
or similar.
|
|
.IP
|
|
.I pathname
|
|
is shown unescaped except for newline characters, which are replaced
|
|
with an octal escape sequence.
|
|
As a result, it is not possible to determine whether the original
|
|
pathname contained a newline character or the literal
|
|
.I \e012
|
|
character sequence.
|
|
.IP
|
|
If the mapping is file-backed and the file has been deleted, the string
|
|
" (deleted)" is appended to the pathname.
|
|
Note that this is ambiguous too.
|
|
.IP
|
|
Under Linux 2.0, there is no field giving pathname.
|
|
.TP
|
|
.I /proc/[pid]/mem
|
|
This file can be used to access the pages of a process's memory through
|
|
.BR open (2),
|
|
.BR read (2),
|
|
and
|
|
.BR lseek (2).
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_ATTACH_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[pid]/mountinfo " (since Linux 2.6.26)"
|
|
.\" This info adapted from Documentation/filesystems/proc.txt
|
|
.\" commit 2d4d4864ac08caff5c204a752bd004eed4f08760
|
|
This file contains information about mounts
|
|
in the process's mount namespace (see
|
|
.BR mount_namespaces (7)).
|
|
It supplies various information
|
|
(e.g., propagation state, root of mount for bind mounts,
|
|
identifier for each mount and its parent) that is missing from the (older)
|
|
.IR /proc/[pid]/mounts
|
|
file, and fixes various other problems with that file
|
|
(e.g., nonextensibility,
|
|
failure to distinguish per-mount versus per-superblock options).
|
|
.IP
|
|
The file contains lines of the form:
|
|
.IP
|
|
.EX
|
|
36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 \- ext3 /dev/root rw,errors=continue
|
|
(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
|
|
.EE
|
|
.IP
|
|
The numbers in parentheses are labels for the descriptions below:
|
|
.RS 7
|
|
.TP 5
|
|
(1)
|
|
mount ID: a unique ID for the mount (may be reused after
|
|
.BR umount (2)).
|
|
.TP
|
|
(2)
|
|
parent ID: the ID of the parent mount
|
|
(or of self for the root of this mount namespace's mount tree).
|
|
.IP
|
|
If a new mount is stacked on top of a previous existing mount
|
|
(so that it hides the existing mount) at pathname P,
|
|
then the parent of the new mount is the previous mount at that location.
|
|
Thus, when looking at all the mounts stacked at a particular location,
|
|
the top-most mount is the one that is not the parent
|
|
of any other mount at the same location.
|
|
(Note, however, that this top-most mount will be accessible only if
|
|
the longest path subprefix of P that is a mount point
|
|
is not itself hidden by a stacked mount.)
|
|
.IP
|
|
If the parent mount lies outside the process's root directory (see
|
|
.BR chroot (2)),
|
|
the ID shown here won't have a corresponding record in
|
|
.I mountinfo
|
|
whose mount ID (field 1) matches this parent mount ID
|
|
(because mounts that lie outside the process's root directory
|
|
are not shown in
|
|
.IR mountinfo ).
|
|
As a special case of this point,
|
|
the process's root mount may have a parent mount
|
|
(for the initramfs filesystem) that lies
|
|
.\" Miklos Szeredi, Nov 2017: The hidden one is the initramfs, I believe
|
|
.\" mtk: In the initial mount namespace, this hidden ID has the value 0
|
|
outside the process's root directory,
|
|
and an entry for that mount will not appear in
|
|
.IR mountinfo .
|
|
.TP
|
|
(3)
|
|
major:minor: the value of
|
|
.I st_dev
|
|
for files on this filesystem (see
|
|
.BR stat (2)).
|
|
.TP
|
|
(4)
|
|
root: the pathname of the directory in the filesystem
|
|
which forms the root of this mount.
|
|
.TP
|
|
(5)
|
|
mount point: the pathname of the mount point relative
|
|
to the process's root directory.
|
|
.TP
|
|
(6)
|
|
mount options: per-mount options (see
|
|
.BR mount (2)).
|
|
.TP
|
|
(7)
|
|
optional fields: zero or more fields of the form "tag[:value]"; see below.
|
|
.TP
|
|
(8)
|
|
separator: the end of the optional fields is marked by a single hyphen.
|
|
.TP
|
|
(9)
|
|
filesystem type: the filesystem type in the form "type[.subtype]".
|
|
.TP
|
|
(10)
|
|
mount source: filesystem-specific information or "none".
|
|
.TP
|
|
(11)
|
|
super options: per-superblock options (see
|
|
.BR mount (2)).
|
|
.RE
|
|
.IP
|
|
Currently, the possible optional fields are
|
|
.IR shared ,
|
|
.IR master ,
|
|
.IR propagate_from ,
|
|
and
|
|
.IR unbindable .
|
|
See
|
|
.BR mount_namespaces (7)
|
|
for a description of these fields.
|
|
Parsers should ignore all unrecognized optional fields.
|
|
.IP
|
|
For more information on mount propagation see
|
|
.I Documentation/filesystems/sharedsubtree.rst
|
|
(or
|
|
.I Documentation/filesystems/sharedsubtree.txt
|
|
before Linux 5.8)
|
|
in the Linux kernel source tree.
|
|
.TP
|
|
.IR /proc/[pid]/mounts " (since Linux 2.4.19)"
|
|
This file lists all the filesystems currently mounted in the
|
|
process's mount namespace (see
|
|
.BR mount_namespaces (7)).
|
|
The format of this file is documented in
|
|
.BR fstab (5).
|
|
.IP
|
|
Since kernel version 2.6.15, this file is pollable:
|
|
after opening the file for reading, a change in this file
|
|
(i.e., a filesystem mount or unmount) causes
|
|
.BR select (2)
|
|
to mark the file descriptor as having an exceptional condition, and
|
|
.BR poll (2)
|
|
and
|
|
.BR epoll_wait (2)
|
|
mark the file as having a priority event
|
|
.RB ( POLLPRI ).
|
|
(Before Linux 2.6.30,
|
|
a change in this file was indicated by the file descriptor
|
|
being marked as readable for
|
|
.BR select (2),
|
|
and being marked as having an error condition for
|
|
.BR poll (2)
|
|
and
|
|
.BR epoll_wait (2).)
|
|
.TP
|
|
.IR /proc/[pid]/mountstats " (since Linux 2.6.17)"
|
|
This file exports information (statistics, configuration information)
|
|
about the mounts in the process's mount namespace (see
|
|
.BR mount_namespaces (7)).
|
|
Lines in this file have the form:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
device /dev/sda7 mounted on /home with fstype ext3 [stats]
|
|
( 1 ) ( 2 ) (3 ) ( 4 )
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields in each line are:
|
|
.RS 7
|
|
.TP 5
|
|
(1)
|
|
The name of the mounted device
|
|
(or "nodevice" if there is no corresponding device).
|
|
.TP
|
|
(2)
|
|
The mount point within the filesystem tree.
|
|
.TP
|
|
(3)
|
|
The filesystem type.
|
|
.TP
|
|
(4)
|
|
Optional statistics and configuration information.
|
|
Currently (as at Linux 2.6.26), only NFS filesystems export
|
|
information via this field.
|
|
.RE
|
|
.IP
|
|
This file is readable only by the owner of the process.
|
|
.TP
|
|
.IR /proc/[pid]/net " (since Linux 2.6.25)"
|
|
See the description of
|
|
.IR /proc/net .
|
|
.TP
|
|
.IR /proc/[pid]/ns/ " (since Linux 3.0)"
|
|
.\" See commit 6b4e306aa3dc94a0545eb9279475b1ab6209a31f
|
|
This is a subdirectory containing one entry for each namespace that
|
|
supports being manipulated by
|
|
.BR setns (2).
|
|
For more information, see
|
|
.BR namespaces (7).
|
|
.TP
|
|
.IR /proc/[pid]/numa_maps " (since Linux 2.6.14)"
|
|
See
|
|
.BR numa (7).
|
|
.TP
|
|
.IR /proc/[pid]/oom_adj " (since Linux 2.6.11)"
|
|
This file can be used to adjust the score used to select which process
|
|
should be killed in an out-of-memory (OOM) situation.
|
|
The kernel uses this value for a bit-shift operation of the process's
|
|
.IR oom_score
|
|
value:
|
|
valid values are in the range \-16 to +15,
|
|
plus the special value \-17,
|
|
which disables OOM-killing altogether for this process.
|
|
A positive score increases the likelihood of this
|
|
process being killed by the OOM-killer;
|
|
a negative score decreases the likelihood.
|
|
.IP
|
|
The default value for this file is 0;
|
|
a new process inherits its parent's
|
|
.I oom_adj
|
|
setting.
|
|
A process must be privileged
|
|
.RB ( CAP_SYS_RESOURCE )
|
|
to update this file.
|
|
.IP
|
|
Since Linux 2.6.36, use of this file is deprecated in favor of
|
|
.IR /proc/[pid]/oom_score_adj .
|
|
.TP
|
|
.IR /proc/[pid]/oom_score " (since Linux 2.6.11)"
|
|
.\" See mm/oom_kill.c::badness() in pre 2.6.36 sources
|
|
.\" See mm/oom_kill.c::oom_badness() after 2.6.36
|
|
.\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10
|
|
This file displays the current score that the kernel gives to
|
|
this process for the purpose of selecting a process
|
|
for the OOM-killer.
|
|
A higher score means that the process is more likely to be
|
|
selected by the OOM-killer.
|
|
The basis for this score is the amount of memory used by the process,
|
|
with increases (+) or decreases (\-) for factors including:
|
|
.\" See mm/oom_kill.c::badness() in pre 2.6.36 sources
|
|
.\" See mm/oom_kill.c::oom_badness() after 2.6.36
|
|
.\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10
|
|
.RS
|
|
.IP * 2
|
|
whether the process is privileged (\-).
|
|
.\" More precisely, if it has CAP_SYS_ADMIN or (pre 2.6.36) CAP_SYS_RESOURCE
|
|
.RE
|
|
.IP
|
|
Before kernel 2.6.36 the following factors were also used in the calculation of oom_score:
|
|
.RS
|
|
.IP * 2
|
|
whether the process creates a lot of children using
|
|
.BR fork (2)
|
|
(+);
|
|
.IP *
|
|
whether the process has been running a long time,
|
|
or has used a lot of CPU time (\-);
|
|
.IP *
|
|
whether the process has a low nice value (i.e., > 0) (+); and
|
|
.IP *
|
|
whether the process is making direct hardware access (\-).
|
|
.\" More precisely, if it has CAP_SYS_RAWIO
|
|
.RE
|
|
.IP
|
|
The
|
|
.I oom_score
|
|
also reflects the adjustment specified by the
|
|
.I oom_score_adj
|
|
or
|
|
.I oom_adj
|
|
setting for the process.
|
|
.TP
|
|
.IR /proc/[pid]/oom_score_adj " (since Linux 2.6.36)"
|
|
.\" Text taken from 3.7 Documentation/filesystems/proc.txt
|
|
This file can be used to adjust the badness heuristic used to select which
|
|
process gets killed in out-of-memory conditions.
|
|
.IP
|
|
The badness heuristic assigns a value to each candidate task ranging from 0
|
|
(never kill) to 1000 (always kill) to determine which process is targeted.
|
|
The units are roughly a proportion along that range of
|
|
allowed memory the process may allocate from,
|
|
based on an estimation of its current memory and swap use.
|
|
For example, if a task is using all allowed memory,
|
|
its badness score will be 1000.
|
|
If it is using half of its allowed memory, its score will be 500.
|
|
.IP
|
|
There is an additional factor included in the badness score: root
|
|
processes are given 3% extra memory over other tasks.
|
|
.IP
|
|
The amount of "allowed" memory depends on the context
|
|
in which the OOM-killer was called.
|
|
If it is due to the memory assigned to the allocating task's cpuset
|
|
being exhausted,
|
|
the allowed memory represents the set of mems assigned to that
|
|
cpuset (see
|
|
.BR cpuset (7)).
|
|
If it is due to a mempolicy's node(s) being exhausted,
|
|
the allowed memory represents the set of mempolicy nodes.
|
|
If it is due to a memory limit (or swap limit) being reached,
|
|
the allowed memory is that configured limit.
|
|
Finally, if it is due to the entire system being out of memory, the
|
|
allowed memory represents all allocatable resources.
|
|
.IP
|
|
The value of
|
|
.I oom_score_adj
|
|
is added to the badness score before it
|
|
is used to determine which task to kill.
|
|
Acceptable values range from \-1000
|
|
(OOM_SCORE_ADJ_MIN) to +1000 (OOM_SCORE_ADJ_MAX).
|
|
This allows user space to control the preference for OOM-killing,
|
|
ranging from always preferring a certain
|
|
task or completely disabling it from OOM-killing.
|
|
The lowest possible value, \-1000, is
|
|
equivalent to disabling OOM-killing entirely for that task,
|
|
since it will always report a badness score of 0.
|
|
.IP
|
|
Consequently, it is very simple for user space to define
|
|
the amount of memory to consider for each task.
|
|
Setting an
|
|
.I oom_score_adj
|
|
value of +500, for example,
|
|
is roughly equivalent to allowing the remainder of tasks sharing the
|
|
same system, cpuset, mempolicy, or memory controller resources
|
|
to use at least 50% more memory.
|
|
A value of \-500, on the other hand, would be roughly
|
|
equivalent to discounting 50% of the task's
|
|
allowed memory from being considered as scoring against the task.
|
|
.IP
|
|
For backward compatibility with previous kernels,
|
|
.I /proc/[pid]/oom_adj
|
|
can still be used to tune the badness score.
|
|
Its value is
|
|
scaled linearly with
|
|
.IR oom_score_adj .
|
|
.IP
|
|
Writing to
|
|
.IR /proc/[pid]/oom_score_adj
|
|
or
|
|
.IR /proc/[pid]/oom_adj
|
|
will change the other with its scaled value.
|
|
.IP
|
|
The
|
|
.BR choom (1)
|
|
program provides a command-line interface for adjusting the
|
|
.I oom_score_adj
|
|
value of a running process or a newly executed command.
|
|
.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\(en57 (since Linux 3.11)
|
|
Zero
|
|
.\" Not quite true; see commit 541c237c0923f567c9c4cabb8a81635baadc713f
|
|
.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\(en0
|
|
If the page is present in RAM (bit 63), then these bits
|
|
provide the page frame number, which can be used to index
|
|
.IR /proc/kpageflags
|
|
and
|
|
.IR /proc/kpagecount .
|
|
If the page is present in swap (bit 62),
|
|
then bits 4\(en0 give the swap type, and bits 54\(en5 encode the swap offset.
|
|
.RE
|
|
.IP
|
|
Before Linux 3.11, bits 60\(en55 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).
|
|
.TP
|
|
.IR /proc/[pid]/personality " (since Linux 2.6.28)"
|
|
.\" commit 478307230810d7e2a753ed220db9066dfdf88718
|
|
This read-only file exposes the process's execution domain, as set by
|
|
.BR personality (2).
|
|
The value is displayed in hexadecimal notation.
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_ATTACH_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.I /proc/[pid]/root
|
|
UNIX and Linux support the idea of a per-process root of the
|
|
filesystem, set by the
|
|
.BR chroot (2)
|
|
system call.
|
|
This file is a symbolic link that points to the process's
|
|
root directory, and behaves in the same way as
|
|
.IR exe ,
|
|
and
|
|
.IR fd/* .
|
|
.IP
|
|
Note however that this file is not merely a symbolic link.
|
|
It provides the same view of the filesystem (including namespaces and the
|
|
set of per-process mounts) as the process itself.
|
|
An example illustrates this point.
|
|
In one terminal, we start a shell in new user and mount namespaces,
|
|
and in that shell we create some new mounts:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
$ \fBPS1=\(aqsh1# \(aq unshare \-Urnm\fP
|
|
sh1# \fBmount \-t tmpfs tmpfs /etc\fP # Mount empty tmpfs at /etc
|
|
sh1# \fBmount \-\-bind /usr /dev\fP # Mount /usr at /dev
|
|
sh1# \fBecho $$\fP
|
|
27123
|
|
.EE
|
|
.in
|
|
.IP
|
|
In a second terminal window, in the initial mount namespace,
|
|
we look at the contents of the corresponding mounts in
|
|
the initial and new namespaces:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
$ \fBPS1=\(aqsh2# \(aq sudo sh\fP
|
|
sh2# \fBls /etc | wc \-l\fP # In initial NS
|
|
309
|
|
sh2# \fBls /proc/27123/root/etc | wc \-l\fP # /etc in other NS
|
|
0 # The empty tmpfs dir
|
|
sh2# \fBls /dev | wc \-l\fP # In initial NS
|
|
205
|
|
sh2# \fBls /proc/27123/root/dev | wc \-l\fP # /dev in other NS
|
|
11 # Actually bind
|
|
# mounted to /usr
|
|
sh2# \fBls /usr | wc \-l\fP # /usr in initial NS
|
|
11
|
|
.EE
|
|
.in
|
|
.IP
|
|
.\" The following was still true as at kernel 2.6.13
|
|
In a multithreaded process, the contents of the
|
|
.I /proc/[pid]/root
|
|
symbolic link are not available if the main thread has already terminated
|
|
(typically by calling
|
|
.BR pthread_exit (3)).
|
|
.IP
|
|
Permission to dereference or read
|
|
.RB ( readlink (2))
|
|
this symbolic link is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[pid]/projid_map " (since Linux 3.7)"
|
|
.\" commit f76d207a66c3a53defea67e7d36c3eb1b7d6d61d
|
|
See
|
|
.BR user_namespaces (7).
|
|
.TP
|
|
.IR /proc/[pid]/seccomp " (Linux 2.6.12 to 2.6.22)"
|
|
This file can be used to read and change the process's
|
|
secure computing (seccomp) mode setting.
|
|
It contains the value 0 if the process is not in seccomp mode,
|
|
and 1 if the process is in strict seccomp mode (see
|
|
.BR seccomp (2)).
|
|
Writing 1 to this file places the process irreversibly in strict seccomp mode.
|
|
(Further attempts to write to the file fail with the
|
|
.B EPERM
|
|
error.)
|
|
.IP
|
|
In Linux 2.6.23,
|
|
this file went away, to be replaced by the
|
|
.BR prctl (2)
|
|
.BR PR_GET_SECCOMP
|
|
and
|
|
.BR PR_SET_SECCOMP
|
|
operations (and later by
|
|
.BR seccomp (2)
|
|
and the
|
|
.I Seccomp
|
|
field in
|
|
.IR /proc/[pid]/status ).
|
|
.\" FIXME Describe /proc/[pid]/sessionid
|
|
.\" commit 1e0bd7550ea9cf474b1ad4c6ff5729a507f75fdc
|
|
.\" CONFIG_AUDITSYSCALL
|
|
.\" Added in 2.6.25; read-only; only readable by real UID
|
|
.\"
|
|
.\" FIXME Describe /proc/[pid]/sched
|
|
.\" Added in 2.6.23
|
|
.\" CONFIG_SCHED_DEBUG, and additional fields if CONFIG_SCHEDSTATS
|
|
.\" Displays various scheduling parameters
|
|
.\" This file can be written, to reset stats
|
|
.\" The set of fields exposed by this file have changed
|
|
.\" significantly over time.
|
|
.\" commit 43ae34cb4cd650d1eb4460a8253a8e747ba052ac
|
|
.\"
|
|
.\" FIXME Describe /proc/[pid]/schedstats and
|
|
.\" /proc/[pid]/task/[tid]/schedstats
|
|
.\" Added in 2.6.9
|
|
.\" CONFIG_SCHEDSTATS
|
|
.TP
|
|
.IR /proc/[pid]/setgroups " (since Linux 3.19)"
|
|
See
|
|
.BR user_namespaces (7).
|
|
.TP
|
|
.IR /proc/[pid]/smaps " (since Linux 2.6.14)"
|
|
This file shows memory consumption for each of the process's mappings.
|
|
(The
|
|
.BR pmap (1)
|
|
command displays similar information,
|
|
in a form that may be easier for parsing.)
|
|
For each mapping there is a series of lines such as the following:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
00400000\-0048a000 r\-xp 00000000 fd:03 960637 /bin/bash
|
|
Size: 552 kB
|
|
Rss: 460 kB
|
|
Pss: 100 kB
|
|
Shared_Clean: 452 kB
|
|
Shared_Dirty: 0 kB
|
|
Private_Clean: 8 kB
|
|
Private_Dirty: 0 kB
|
|
Referenced: 460 kB
|
|
Anonymous: 0 kB
|
|
AnonHugePages: 0 kB
|
|
ShmemHugePages: 0 kB
|
|
ShmemPmdMapped: 0 kB
|
|
Swap: 0 kB
|
|
KernelPageSize: 4 kB
|
|
MMUPageSize: 4 kB
|
|
KernelPageSize: 4 kB
|
|
MMUPageSize: 4 kB
|
|
Locked: 0 kB
|
|
ProtectionKey: 0
|
|
VmFlags: rd ex mr mw me dw
|
|
.EE
|
|
.in
|
|
.IP
|
|
The first of these lines shows the same information as is displayed
|
|
for the mapping in
|
|
.IR /proc/[pid]/maps .
|
|
The following lines show the size of the mapping,
|
|
the amount of the mapping that is currently resident in RAM ("Rss"),
|
|
the process's proportional share of this mapping ("Pss"),
|
|
the number of clean and dirty shared pages in the mapping,
|
|
and the number of clean and dirty private pages in the mapping.
|
|
"Referenced" indicates the amount of memory currently marked as
|
|
referenced or accessed.
|
|
"Anonymous" shows the amount of memory
|
|
that does not belong to any file.
|
|
"Swap" shows how much
|
|
would-be-anonymous memory is also used, but out on swap.
|
|
.IP
|
|
The "KernelPageSize" line (available since Linux 2.6.29)
|
|
is the page size used by the kernel to back the virtual memory area.
|
|
This matches the size used by the MMU in the majority of cases.
|
|
However, one counter-example occurs on PPC64 kernels
|
|
whereby a kernel using 64 kB as a base page size may still use 4 kB
|
|
pages for the MMU on older processors.
|
|
To distinguish the two attributes, the "MMUPageSize" line
|
|
(also available since Linux 2.6.29)
|
|
reports the page size used by the MMU.
|
|
.IP
|
|
The "Locked" indicates whether the mapping is locked in memory
|
|
or not.
|
|
.IP
|
|
The "ProtectionKey" line (available since Linux 4.9, on x86 only)
|
|
contains the memory protection key (see
|
|
.BR pkeys (7))
|
|
associated with the virtual memory area.
|
|
This entry is present only if the kernel was built with the
|
|
.B CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
|
|
configuration option (since Linux 4.6).
|
|
.IP
|
|
The "VmFlags" line (available since Linux 3.8)
|
|
represents the kernel flags associated with the virtual memory area,
|
|
encoded using the following two-letter codes:
|
|
.IP
|
|
rd - readable
|
|
wr - writable
|
|
ex - executable
|
|
sh - shared
|
|
mr - may read
|
|
mw - may write
|
|
me - may execute
|
|
ms - may share
|
|
gd - stack segment grows down
|
|
pf - pure PFN range
|
|
dw - disabled write to the mapped file
|
|
lo - pages are locked in memory
|
|
io - memory mapped I/O area
|
|
sr - sequential read advise provided
|
|
rr - random read advise provided
|
|
dc - do not copy area on fork
|
|
de - do not expand area on remapping
|
|
ac - area is accountable
|
|
nr - swap space is not reserved for the area
|
|
ht - area uses huge tlb pages
|
|
sf - perform synchronous page faults (since Linux 4.15)
|
|
nl - non-linear mapping (removed in Linux 4.0)
|
|
ar - architecture specific flag
|
|
wf - wipe on fork (since Linux 4.14)
|
|
dd - do not include area into core dump
|
|
sd - soft-dirty flag (since Linux 3.13)
|
|
mm - mixed map area
|
|
hg - huge page advise flag
|
|
nh - no-huge page advise flag
|
|
mg - mergeable advise flag
|
|
um - userfaultfd missing pages tracking (since Linux 4.3)
|
|
uw - userfaultfd wprotect pages tracking (since Linux 4.3)
|
|
.IP
|
|
The
|
|
.IR /proc/[pid]/smaps
|
|
file is present only if the
|
|
.B CONFIG_PROC_PAGE_MONITOR
|
|
kernel configuration option is enabled.
|
|
.TP
|
|
.IR /proc/[pid]/stack " (since Linux 2.6.29)"
|
|
.\" 2ec220e27f5040aec1e88901c1b6ea3d135787ad
|
|
This file provides a symbolic trace of the function calls in this
|
|
process's kernel stack.
|
|
This file is provided only if the kernel was built with the
|
|
.B CONFIG_STACKTRACE
|
|
configuration option.
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_ATTACH_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.I /proc/[pid]/stat
|
|
Status information about the process.
|
|
This is used by
|
|
.BR ps (1).
|
|
It is defined in the kernel source file
|
|
.IR fs/proc/array.c "."
|
|
.IP
|
|
The fields, in order, with their proper
|
|
.BR scanf (3)
|
|
format specifiers, are listed below.
|
|
Whether or not certain of these fields display valid information is governed by
|
|
a ptrace access mode
|
|
.BR PTRACE_MODE_READ_FSCREDS " | " PTRACE_MODE_NOAUDIT
|
|
check (refer to
|
|
.BR ptrace (2)).
|
|
If the check denies access, then the field value is displayed as 0.
|
|
The affected fields are indicated with the marking [PT].
|
|
.RS
|
|
.TP
|
|
(1) \fIpid\fP \ %d
|
|
.br
|
|
The process ID.
|
|
.TP
|
|
(2) \fIcomm\fP \ %s
|
|
The filename of the executable, in parentheses.
|
|
Strings longer than
|
|
.B TASK_COMM_LEN
|
|
(16) characters (including the terminating null byte) are silently truncated.
|
|
This is visible whether or not the executable is swapped out.
|
|
.TP
|
|
(3) \fIstate\fP \ %c
|
|
One of the following characters, indicating process state:
|
|
.RS
|
|
.IP R 3
|
|
Running
|
|
.IP S
|
|
Sleeping in an interruptible wait
|
|
.IP D
|
|
Waiting in uninterruptible
|
|
disk sleep
|
|
.IP Z
|
|
Zombie
|
|
.IP T
|
|
Stopped (on a signal) or (before Linux 2.6.33) trace stopped
|
|
.IP t
|
|
.\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29
|
|
Tracing stop (Linux 2.6.33 onward)
|
|
.IP W
|
|
Paging (only before Linux 2.6.0)
|
|
.IP X
|
|
Dead (from Linux 2.6.0 onward)
|
|
.IP x
|
|
.\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29
|
|
Dead (Linux 2.6.33 to
|
|
.\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457
|
|
3.13 only)
|
|
.IP K
|
|
.\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29
|
|
Wakekill (Linux 2.6.33 to
|
|
.\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457
|
|
3.13 only)
|
|
.IP W
|
|
.\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29
|
|
Waking (Linux 2.6.33 to
|
|
.\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457
|
|
3.13 only)
|
|
.IP P
|
|
.\" commit f2530dc71cf0822f90bb63ea4600caaef33a66bb
|
|
Parked (Linux 3.9 to
|
|
.\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457
|
|
3.13 only)
|
|
.RE
|
|
.TP
|
|
(4) \fIppid\fP \ %d
|
|
The PID of the parent of this process.
|
|
.TP
|
|
(5) \fIpgrp\fP \ %d
|
|
The process group ID of the process.
|
|
.TP
|
|
(6) \fIsession\fP \ %d
|
|
The session ID of the process.
|
|
.TP
|
|
(7) \fItty_nr\fP \ %d
|
|
The controlling terminal of the process.
|
|
(The minor device number is contained in the combination of bits
|
|
31 to 20 and 7 to 0;
|
|
the major device number is in bits 15 to 8.)
|
|
.TP
|
|
(8) \fItpgid\fP \ %d
|
|
.\" This field and following, up to and including wchan added 0.99.1
|
|
The ID of the foreground process group of the controlling
|
|
terminal of the process.
|
|
.TP
|
|
(9) \fIflags\fP \ %u
|
|
The kernel flags word of the process.
|
|
For bit meanings,
|
|
see the PF_* defines in the Linux kernel source file
|
|
.IR include/linux/sched.h .
|
|
Details depend on the kernel version.
|
|
.IP
|
|
The format for this field was %lu before Linux 2.6.
|
|
.TP
|
|
(10) \fIminflt\fP \ %lu
|
|
The number of minor faults the process has made which have not
|
|
required loading a memory page from disk.
|
|
.TP
|
|
(11) \fIcminflt\fP \ %lu
|
|
The number of minor faults that the process's
|
|
waited-for children have made.
|
|
.TP
|
|
(12) \fImajflt\fP \ %lu
|
|
The number of major faults the process has made which have
|
|
required loading a memory page from disk.
|
|
.TP
|
|
(13) \fIcmajflt\fP \ %lu
|
|
The number of major faults that the process's
|
|
waited-for children have made.
|
|
.TP
|
|
(14) \fIutime\fP \ %lu
|
|
Amount of time that this process has been scheduled in user mode,
|
|
measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
This includes guest time, \fIguest_time\fP
|
|
(time spent running a virtual CPU, see below),
|
|
so that applications that are not aware of the guest time field
|
|
do not lose that time from their calculations.
|
|
.TP
|
|
(15) \fIstime\fP \ %lu
|
|
Amount of time that this process has been scheduled in kernel mode,
|
|
measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
.TP
|
|
(16) \fIcutime\fP \ %ld
|
|
Amount of time that this process's
|
|
waited-for children have been scheduled in user mode,
|
|
measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
(See also
|
|
.BR times (2).)
|
|
This includes guest time, \fIcguest_time\fP
|
|
(time spent running a virtual CPU, see below).
|
|
.TP
|
|
(17) \fIcstime\fP \ %ld
|
|
Amount of time that this process's
|
|
waited-for children have been scheduled in kernel mode,
|
|
measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
.TP
|
|
(18) \fIpriority\fP \ %ld
|
|
(Explanation for Linux 2.6)
|
|
For processes running a real-time scheduling policy
|
|
.RI ( policy
|
|
below; see
|
|
.BR sched_setscheduler (2)),
|
|
this is the negated scheduling priority, minus one;
|
|
that is, a number in the range \-2 to \-100,
|
|
corresponding to real-time priorities 1 to 99.
|
|
For processes running under a non-real-time scheduling policy,
|
|
this is the raw nice value
|
|
.RB ( setpriority (2))
|
|
as represented in the kernel.
|
|
The kernel stores nice values as numbers
|
|
in the range 0 (high) to 39 (low),
|
|
corresponding to the user-visible nice range of \-20 to 19.
|
|
.IP
|
|
Before Linux 2.6, this was a scaled value based on
|
|
the scheduler weighting given to this process.
|
|
.\" And back in kernel 1.2 days things were different again.
|
|
.TP
|
|
(19) \fInice\fP \ %ld
|
|
The nice value (see
|
|
.BR setpriority (2)),
|
|
a value in the range 19 (low priority) to \-20 (high priority).
|
|
.\" Back in kernel 1.2 days things were different.
|
|
.\" .TP
|
|
.\" \fIcounter\fP %ld
|
|
.\" The current maximum size in jiffies of the process's next timeslice,
|
|
.\" or what is currently left of its current timeslice, if it is the
|
|
.\" currently running process.
|
|
.\" .TP
|
|
.\" \fItimeout\fP %u
|
|
.\" The time in jiffies of the process's next timeout.
|
|
.\" timeout was removed sometime around 2.1/2.2
|
|
.TP
|
|
(20) \fInum_threads\fP \ %ld
|
|
Number of threads in this process (since Linux 2.6).
|
|
Before kernel 2.6, this field was hard coded to 0 as a placeholder
|
|
for an earlier removed field.
|
|
.TP
|
|
(21) \fIitrealvalue\fP \ %ld
|
|
The time in jiffies before the next
|
|
.B SIGALRM
|
|
is sent to the process due to an interval timer.
|
|
Since kernel 2.6.17, this field is no longer maintained,
|
|
and is hard coded as 0.
|
|
.TP
|
|
(22) \fIstarttime\fP \ %llu
|
|
The time the process started after system boot.
|
|
In kernels before Linux 2.6, this value was expressed in jiffies.
|
|
Since Linux 2.6, the value is expressed in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
.IP
|
|
The format for this field was %lu before Linux 2.6.
|
|
.TP
|
|
(23) \fIvsize\fP \ %lu
|
|
Virtual memory size in bytes.
|
|
.TP
|
|
(24) \fIrss\fP \ %ld
|
|
Resident Set Size: number of pages the process has in real memory.
|
|
This is just the pages which
|
|
count toward text, data, or stack space.
|
|
This does not include pages
|
|
which have not been demand-loaded in, or which are swapped out.
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
below.
|
|
.TP
|
|
(25) \fIrsslim\fP \ %lu
|
|
Current soft limit in bytes on the rss of the process;
|
|
see the description of
|
|
.B RLIMIT_RSS
|
|
in
|
|
.BR getrlimit (2).
|
|
.TP
|
|
(26) \fIstartcode\fP \ %lu \ [PT]
|
|
The address above which program text can run.
|
|
.TP
|
|
(27) \fIendcode\fP \ %lu \ [PT]
|
|
The address below which program text can run.
|
|
.TP
|
|
(28) \fIstartstack\fP \ %lu \ [PT]
|
|
The address of the start (i.e., bottom) of the stack.
|
|
.TP
|
|
(29) \fIkstkesp\fP \ %lu \ [PT]
|
|
The current value of ESP (stack pointer), as found in the
|
|
kernel stack page for the process.
|
|
.TP
|
|
(30) \fIkstkeip\fP \ %lu \ [PT]
|
|
The current EIP (instruction pointer).
|
|
.TP
|
|
(31) \fIsignal\fP \ %lu
|
|
The bitmap of pending signals, displayed as a decimal number.
|
|
Obsolete, because it does not provide information on real-time signals; use
|
|
.I /proc/[pid]/status
|
|
instead.
|
|
.TP
|
|
(32) \fIblocked\fP \ %lu
|
|
The bitmap of blocked signals, displayed as a decimal number.
|
|
Obsolete, because it does not provide information on real-time signals; use
|
|
.I /proc/[pid]/status
|
|
instead.
|
|
.TP
|
|
(33) \fIsigignore\fP \ %lu
|
|
The bitmap of ignored signals, displayed as a decimal number.
|
|
Obsolete, because it does not provide information on real-time signals; use
|
|
.I /proc/[pid]/status
|
|
instead.
|
|
.TP
|
|
(34) \fIsigcatch\fP \ %lu
|
|
The bitmap of caught signals, displayed as a decimal number.
|
|
Obsolete, because it does not provide information on real-time signals; use
|
|
.I /proc/[pid]/status
|
|
instead.
|
|
.TP
|
|
(35) \fIwchan\fP \ %lu \ [PT]
|
|
This is the "channel" in which the process is waiting.
|
|
It is the address of a location in the kernel where the process is sleeping.
|
|
The corresponding symbolic name can be found in
|
|
.IR /proc/[pid]/wchan .
|
|
.TP
|
|
(36) \fInswap\fP \ %lu
|
|
.\" nswap was added in 2.0
|
|
Number of pages swapped (not maintained).
|
|
.TP
|
|
(37) \fIcnswap\fP \ %lu
|
|
.\" cnswap was added in 2.0
|
|
Cumulative \fInswap\fP for child processes (not maintained).
|
|
.TP
|
|
(38) \fIexit_signal\fP \ %d \ (since Linux 2.1.22)
|
|
Signal to be sent to parent when we die.
|
|
.TP
|
|
(39) \fIprocessor\fP \ %d \ (since Linux 2.2.8)
|
|
CPU number last executed on.
|
|
.TP
|
|
(40) \fIrt_priority\fP \ %u \ (since Linux 2.5.19)
|
|
Real-time scheduling priority, a number in the range 1 to 99 for
|
|
processes scheduled under a real-time policy,
|
|
or 0, for non-real-time processes (see
|
|
.BR sched_setscheduler (2)).
|
|
.TP
|
|
(41) \fIpolicy\fP \ %u \ (since Linux 2.5.19)
|
|
Scheduling policy (see
|
|
.BR sched_setscheduler (2)).
|
|
Decode using the SCHED_* constants in
|
|
.IR linux/sched.h .
|
|
.IP
|
|
The format for this field was %lu before Linux 2.6.22.
|
|
.TP
|
|
(42) \fIdelayacct_blkio_ticks\fP \ %llu \ (since Linux 2.6.18)
|
|
Aggregated block I/O delays, measured in clock ticks (centiseconds).
|
|
.TP
|
|
(43) \fIguest_time\fP \ %lu \ (since Linux 2.6.24)
|
|
Guest time of the process (time spent running a virtual CPU
|
|
for a guest operating system), measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
.TP
|
|
(44) \fIcguest_time\fP \ %ld \ (since Linux 2.6.24)
|
|
Guest time of the process's children, measured in clock ticks (divide by
|
|
.IR sysconf(_SC_CLK_TCK) ).
|
|
.TP
|
|
(45) \fIstart_data\fP \ %lu \ (since Linux 3.3) \ [PT]
|
|
.\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff
|
|
Address above which program initialized and
|
|
uninitialized (BSS) data are placed.
|
|
.TP
|
|
(46) \fIend_data\fP \ %lu \ (since Linux 3.3) \ [PT]
|
|
.\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff
|
|
Address below which program initialized and
|
|
uninitialized (BSS) data are placed.
|
|
.TP
|
|
(47) \fIstart_brk\fP \ %lu \ (since Linux 3.3) \ [PT]
|
|
.\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff
|
|
Address above which program heap can be expanded with
|
|
.BR brk (2).
|
|
.TP
|
|
(48) \fIarg_start\fP \ %lu \ (since Linux 3.5) \ [PT]
|
|
.\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3
|
|
Address above which program command-line arguments
|
|
.RI ( argv )
|
|
are placed.
|
|
.TP
|
|
(49) \fIarg_end\fP \ %lu \ (since Linux 3.5) \ [PT]
|
|
.\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3
|
|
Address below program command-line arguments
|
|
.RI ( argv )
|
|
are placed.
|
|
.TP
|
|
(50) \fIenv_start\fP \ %lu \ (since Linux 3.5) \ [PT]
|
|
.\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3
|
|
Address above which program environment is placed.
|
|
.TP
|
|
(51) \fIenv_end\fP \ %lu \ (since Linux 3.5) \ [PT]
|
|
.\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3
|
|
Address below which program environment is placed.
|
|
.TP
|
|
(52) \fIexit_code\fP \ %d \ (since Linux 3.5) \ [PT]
|
|
.\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3
|
|
The thread's exit status in the form reported by
|
|
.BR waitpid (2).
|
|
.RE
|
|
.TP
|
|
.I /proc/[pid]/statm
|
|
Provides information about memory usage, measured in pages.
|
|
The columns are:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
size (1) total program size
|
|
(same as VmSize in \fI/proc/[pid]/status\fP)
|
|
resident (2) resident set size
|
|
(inaccurate; same as VmRSS in \fI/proc/[pid]/status\fP)
|
|
shared (3) number of resident shared pages
|
|
(i.e., backed by a file)
|
|
(inaccurate; same as RssFile+RssShmem in
|
|
\fI/proc/[pid]/status\fP)
|
|
text (4) text (code)
|
|
.\" (not including libs; broken, includes data segment)
|
|
lib (5) library (unused since Linux 2.6; always 0)
|
|
data (6) data + stack
|
|
.\" (including libs; broken, includes library text)
|
|
dt (7) dirty pages (unused since Linux 2.6; always 0)
|
|
.EE
|
|
.in
|
|
.IP
|
|
.\" See SPLIT_RSS_COUNTING in the kernel.
|
|
.\" Inaccuracy is bounded by TASK_RSS_EVENTS_THRESH.
|
|
Some of these values are inaccurate because
|
|
of a kernel-internal scalability optimization.
|
|
If accurate values are required, use
|
|
.I /proc/[pid]/smaps
|
|
or
|
|
.I /proc/[pid]/smaps_rollup
|
|
instead, which are much slower but provide accurate, detailed information.
|
|
.TP
|
|
.I /proc/[pid]/status
|
|
Provides much of the information in
|
|
.I /proc/[pid]/stat
|
|
and
|
|
.I /proc/[pid]/statm
|
|
in a format that's easier for humans to parse.
|
|
Here's an example:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " cat /proc/$$/status"
|
|
Name: bash
|
|
Umask: 0022
|
|
State: S (sleeping)
|
|
Tgid: 17248
|
|
Ngid: 0
|
|
Pid: 17248
|
|
PPid: 17200
|
|
TracerPid: 0
|
|
Uid: 1000 1000 1000 1000
|
|
Gid: 100 100 100 100
|
|
FDSize: 256
|
|
Groups: 16 33 100
|
|
NStgid: 17248
|
|
NSpid: 17248
|
|
NSpgid: 17248
|
|
NSsid: 17200
|
|
VmPeak: 131168 kB
|
|
VmSize: 131168 kB
|
|
VmLck: 0 kB
|
|
VmPin: 0 kB
|
|
VmHWM: 13484 kB
|
|
VmRSS: 13484 kB
|
|
RssAnon: 10264 kB
|
|
RssFile: 3220 kB
|
|
RssShmem: 0 kB
|
|
VmData: 10332 kB
|
|
VmStk: 136 kB
|
|
VmExe: 992 kB
|
|
VmLib: 2104 kB
|
|
VmPTE: 76 kB
|
|
VmPMD: 12 kB
|
|
VmSwap: 0 kB
|
|
HugetlbPages: 0 kB # 4.4
|
|
CoreDumping: 0 # 4.15
|
|
Threads: 1
|
|
SigQ: 0/3067
|
|
SigPnd: 0000000000000000
|
|
ShdPnd: 0000000000000000
|
|
SigBlk: 0000000000010000
|
|
SigIgn: 0000000000384004
|
|
SigCgt: 000000004b813efb
|
|
CapInh: 0000000000000000
|
|
CapPrm: 0000000000000000
|
|
CapEff: 0000000000000000
|
|
CapBnd: ffffffffffffffff
|
|
CapAmb: 0000000000000000
|
|
NoNewPrivs: 0
|
|
Seccomp: 0
|
|
Speculation_Store_Bypass: vulnerable
|
|
Cpus_allowed: 00000001
|
|
Cpus_allowed_list: 0
|
|
Mems_allowed: 1
|
|
Mems_allowed_list: 0
|
|
voluntary_ctxt_switches: 150
|
|
nonvoluntary_ctxt_switches: 545
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields are as follows:
|
|
.RS
|
|
.TP
|
|
.IR Name
|
|
Command run by this process.
|
|
Strings longer than
|
|
.B TASK_COMM_LEN
|
|
(16) characters (including the terminating null byte) are silently truncated.
|
|
.TP
|
|
.IR Umask
|
|
Process umask, expressed in octal with a leading zero; see
|
|
.BR umask (2).
|
|
(Since Linux 4.7.)
|
|
.TP
|
|
.IR State
|
|
Current state of the process.
|
|
One of
|
|
"R (running)",
|
|
"S (sleeping)",
|
|
"D (disk sleep)",
|
|
"T (stopped)",
|
|
"t (tracing stop)",
|
|
"Z (zombie)",
|
|
or
|
|
"X (dead)".
|
|
.TP
|
|
.IR Tgid
|
|
Thread group ID (i.e., Process ID).
|
|
.TP
|
|
.IR Ngid
|
|
NUMA group ID (0 if none; since Linux 3.13).
|
|
.TP
|
|
.IR Pid
|
|
Thread ID (see
|
|
.BR gettid (2)).
|
|
.TP
|
|
.IR PPid
|
|
PID of parent process.
|
|
.TP
|
|
.IR TracerPid
|
|
PID of process tracing this process (0 if not being traced).
|
|
.TP
|
|
.IR Uid ", " Gid
|
|
Real, effective, saved set, and filesystem UIDs (GIDs).
|
|
.TP
|
|
.IR FDSize
|
|
Number of file descriptor slots currently allocated.
|
|
.TP
|
|
.IR Groups
|
|
Supplementary group list.
|
|
.TP
|
|
.IR NStgid
|
|
Thread group ID (i.e., PID) in each of the PID namespaces of which
|
|
.I [pid]
|
|
is a member.
|
|
The leftmost entry shows the value with respect to the PID namespace
|
|
of the process that mounted this procfs (or the root namespace
|
|
if mounted by the kernel),
|
|
followed by the value in successively nested inner namespaces.
|
|
.\" commit e4bc33245124db69b74a6d853ac76c2976f472d5
|
|
(Since Linux 4.1.)
|
|
.TP
|
|
.IR NSpid
|
|
Thread ID in each of the PID namespaces of which
|
|
.I [pid]
|
|
is a member.
|
|
The fields are ordered as for
|
|
.IR NStgid .
|
|
(Since Linux 4.1.)
|
|
.TP
|
|
.IR NSpgid
|
|
Process group ID in each of the PID namespaces of which
|
|
.I [pid]
|
|
is a member.
|
|
The fields are ordered as for
|
|
.IR NStgid .
|
|
(Since Linux 4.1.)
|
|
.TP
|
|
.IR NSsid
|
|
descendant namespace session ID hierarchy
|
|
Session ID in each of the PID namespaces of which
|
|
.I [pid]
|
|
is a member.
|
|
The fields are ordered as for
|
|
.IR NStgid .
|
|
(Since Linux 4.1.)
|
|
.TP
|
|
.IR VmPeak
|
|
Peak virtual memory size.
|
|
.TP
|
|
.IR VmSize
|
|
Virtual memory size.
|
|
.TP
|
|
.IR VmLck
|
|
Locked memory size (see
|
|
.BR mlock (2)).
|
|
.TP
|
|
.IR VmPin
|
|
Pinned memory size
|
|
.\" commit bc3e53f682d93df677dbd5006a404722b3adfe18
|
|
(since Linux 3.2).
|
|
These are pages that can't be moved because something needs to
|
|
directly access physical memory.
|
|
.TP
|
|
.IR VmHWM
|
|
Peak resident set size ("high water mark").
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR VmRSS
|
|
Resident set size.
|
|
Note that the value here is the sum of
|
|
.IR RssAnon ,
|
|
.IR RssFile ,
|
|
and
|
|
.IR RssShmem .
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR RssAnon
|
|
Size of resident anonymous memory.
|
|
.\" commit bf9683d6990589390b5178dafe8fd06808869293
|
|
(since Linux 4.5).
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR RssFile
|
|
Size of resident file mappings.
|
|
.\" commit bf9683d6990589390b5178dafe8fd06808869293
|
|
(since Linux 4.5).
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR RssShmem
|
|
Size of resident shared memory (includes System V shared memory,
|
|
mappings from
|
|
.BR tmpfs (5),
|
|
and shared anonymous mappings).
|
|
.\" commit bf9683d6990589390b5178dafe8fd06808869293
|
|
(since Linux 4.5).
|
|
.TP
|
|
.IR VmData ", " VmStk ", " VmExe
|
|
Size of data, stack, and text segments.
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR VmLib
|
|
Shared library code size.
|
|
.TP
|
|
.IR VmPTE
|
|
Page table entries size (since Linux 2.6.10).
|
|
.TP
|
|
.IR VmPMD
|
|
.\" commit dc6c9a35b66b520cf67e05d8ca60ebecad3b0479
|
|
Size of second-level page tables (added in Linux 4.0; removed in Linux 4.15).
|
|
.TP
|
|
.IR VmSwap
|
|
.\" commit b084d4353ff99d824d3bc5a5c2c22c70b1fba722
|
|
Swapped-out virtual memory size by anonymous private pages;
|
|
shmem swap usage is not included (since Linux 2.6.34).
|
|
This value is inaccurate; see
|
|
.I /proc/[pid]/statm
|
|
above.
|
|
.TP
|
|
.IR HugetlbPages
|
|
Size of hugetlb memory portions
|
|
.\" commit 5d317b2b6536592a9b51fe65faed43d65ca9158e
|
|
(since Linux 4.4).
|
|
.TP
|
|
.IR CoreDumping
|
|
Contains the value 1 if the process is currently dumping core,
|
|
and 0 if it is not
|
|
.\" commit c643401218be0f4ab3522e0c0a63016596d6e9ca
|
|
(since Linux 4.15).
|
|
This information can be used by a monitoring process to avoid killing
|
|
a process that is currently dumping core,
|
|
which could result in a corrupted core dump file.
|
|
.TP
|
|
.IR Threads
|
|
Number of threads in process containing this thread.
|
|
.TP
|
|
.IR SigQ
|
|
This field contains two slash-separated numbers that relate to
|
|
queued signals for the real user ID of this process.
|
|
The first of these is the number of currently queued
|
|
signals for this real user ID, and the second is the
|
|
resource limit on the number of queued signals for this process
|
|
(see the description of
|
|
.BR RLIMIT_SIGPENDING
|
|
in
|
|
.BR getrlimit (2)).
|
|
.TP
|
|
.IR SigPnd ", " ShdPnd
|
|
Mask (expressed in hexadecimal)
|
|
of signals pending for thread and for process as a whole (see
|
|
.BR pthreads (7)
|
|
and
|
|
.BR signal (7)).
|
|
.TP
|
|
.IR SigBlk ", " SigIgn ", " SigCgt
|
|
Masks (expressed in hexadecimal)
|
|
indicating signals being blocked, ignored, and caught (see
|
|
.BR signal (7)).
|
|
.TP
|
|
.IR CapInh ", " CapPrm ", " CapEff
|
|
Masks (expressed in hexadecimal)
|
|
of capabilities enabled in inheritable, permitted, and effective sets
|
|
(see
|
|
.BR capabilities (7)).
|
|
.TP
|
|
.IR CapBnd
|
|
Capability bounding set, expressed in hexadecimal
|
|
(since Linux 2.6.26, see
|
|
.BR capabilities (7)).
|
|
.TP
|
|
.IR CapAmb
|
|
Ambient capability set, expressed in hexadecimal
|
|
(since Linux 4.3, see
|
|
.BR capabilities (7)).
|
|
.TP
|
|
.IR NoNewPrivs
|
|
.\" commit af884cd4a5ae62fcf5e321fecf0ec1014730353d
|
|
Value of the
|
|
.I no_new_privs
|
|
bit
|
|
(since Linux 4.10, see
|
|
.BR prctl (2)).
|
|
.TP
|
|
.IR Seccomp
|
|
.\" commit 2f4b3bf6b2318cfaa177ec5a802f4d8d6afbd816
|
|
Seccomp mode of the process
|
|
(since Linux 3.8, see
|
|
.BR seccomp (2)).
|
|
0 means
|
|
.BR SECCOMP_MODE_DISABLED ;
|
|
1 means
|
|
.BR SECCOMP_MODE_STRICT ;
|
|
2 means
|
|
.BR SECCOMP_MODE_FILTER .
|
|
This field is provided only if the kernel was built with the
|
|
.BR CONFIG_SECCOMP
|
|
kernel configuration option enabled.
|
|
.TP
|
|
.IR Speculation_Store_Bypass
|
|
.\" commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64
|
|
Speculation flaw mitigation state
|
|
(since Linux 4.17, see
|
|
.BR prctl (2)).
|
|
.TP
|
|
.IR Cpus_allowed
|
|
Hexadecimal mask of CPUs on which this process may run
|
|
(since Linux 2.6.24, see
|
|
.BR cpuset (7)).
|
|
.TP
|
|
.IR Cpus_allowed_list
|
|
Same as previous, but in "list format"
|
|
(since Linux 2.6.26, see
|
|
.BR cpuset (7)).
|
|
.TP
|
|
.IR Mems_allowed
|
|
Mask of memory nodes allowed to this process
|
|
(since Linux 2.6.24, see
|
|
.BR cpuset (7)).
|
|
.TP
|
|
.IR Mems_allowed_list
|
|
Same as previous, but in "list format"
|
|
(since Linux 2.6.26, see
|
|
.BR cpuset (7)).
|
|
.TP
|
|
.IR voluntary_ctxt_switches ", " nonvoluntary_ctxt_switches
|
|
Number of voluntary and involuntary context switches (since Linux 2.6.23).
|
|
.RE
|
|
.TP
|
|
.IR /proc/[pid]/syscall " (since Linux 2.6.27)"
|
|
.\" commit ebcb67341fee34061430f3367f2e507e52ee051b
|
|
This file exposes the system call number and argument registers for the
|
|
system call currently being executed by the process,
|
|
followed by the values of the stack pointer and program counter registers.
|
|
The values of all six argument registers are exposed,
|
|
although most system calls use fewer registers.
|
|
.IP
|
|
If the process is blocked, but not in a system call,
|
|
then the file displays \-1 in place of the system call number,
|
|
followed by just the values of the stack pointer and program counter.
|
|
If process is not blocked, then the file contains just the string "running".
|
|
.IP
|
|
This file is present only if the kernel was configured with
|
|
.BR CONFIG_HAVE_ARCH_TRACEHOOK .
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_ATTACH_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[pid]/task " (since Linux 2.6.0)"
|
|
.\" Precisely: Linux 2.6.0-test6
|
|
This is a directory that contains one subdirectory
|
|
for each thread in the process.
|
|
The name of each subdirectory is the numerical thread ID
|
|
.RI ( [tid] )
|
|
of the thread (see
|
|
.BR gettid (2)).
|
|
.IP
|
|
Within each of these subdirectories, there is a set of
|
|
files with the same names and contents as under the
|
|
.I /proc/[pid]
|
|
directories.
|
|
For attributes that are shared by all threads, the contents for
|
|
each of the files under the
|
|
.I task/[tid]
|
|
subdirectories will be the same as in the corresponding
|
|
file in the parent
|
|
.I /proc/[pid]
|
|
directory
|
|
(e.g., in a multithreaded process, all of the
|
|
.I task/[tid]/cwd
|
|
files will have the same value as the
|
|
.I /proc/[pid]/cwd
|
|
file in the parent directory, since all of the threads in a process
|
|
share a working directory).
|
|
For attributes that are distinct for each thread,
|
|
the corresponding files under
|
|
.I task/[tid]
|
|
may have different values (e.g., various fields in each of the
|
|
.I task/[tid]/status
|
|
files may be different for each thread),
|
|
.\" in particular: "children" :/
|
|
or they might not exist in
|
|
.I /proc/[pid]
|
|
at all.
|
|
.IP
|
|
.\" The following was still true as at kernel 2.6.13
|
|
In a multithreaded process, the contents of the
|
|
.I /proc/[pid]/task
|
|
directory are not available if the main thread has already terminated
|
|
(typically by calling
|
|
.BR pthread_exit (3)).
|
|
.TP
|
|
.IR /proc/[pid]/task/[tid]/children " (since Linux 3.5)"
|
|
.\" commit 818411616baf46ceba0cff6f05af3a9b294734f7
|
|
A space-separated list of child tasks of this task.
|
|
Each child task is represented by its TID.
|
|
.IP
|
|
.\" see comments in get_children_pid() in fs/proc/array.c
|
|
This option is intended for use by the checkpoint-restore (CRIU) system,
|
|
and reliably provides a list of children only if all of the child processes
|
|
are stopped or frozen.
|
|
It does not work properly if children of the target task exit while
|
|
the file is being read!
|
|
Exiting children may cause non-exiting children to be omitted from the list.
|
|
This makes this interface even more unreliable than classic PID-based
|
|
approaches if the inspected task and its children aren't frozen,
|
|
and most code should probably not use this interface.
|
|
.IP
|
|
Until Linux 4.2, the presence of this file was governed by the
|
|
.B CONFIG_CHECKPOINT_RESTORE
|
|
kernel configuration option.
|
|
Since Linux 4.2,
|
|
.\" commit 2e13ba54a2682eea24918b87ad3edf70c2cf085b
|
|
it is governed by the
|
|
.B CONFIG_PROC_CHILDREN
|
|
option.
|
|
.TP
|
|
.IR /proc/[pid]/timers " (since Linux 3.10)"
|
|
.\" commit 5ed67f05f66c41e39880a6d61358438a25f9fee5
|
|
.\" commit 48f6a7a511ef8823fdff39afee0320092d43a8a0
|
|
A list of the POSIX timers for this process.
|
|
Each timer is listed with a line that starts with the string "ID:".
|
|
For example:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
ID: 1
|
|
signal: 60/00007fff86e452a8
|
|
notify: signal/pid.2634
|
|
ClockID: 0
|
|
ID: 0
|
|
signal: 60/00007fff86e452a8
|
|
notify: signal/pid.2634
|
|
ClockID: 1
|
|
.EE
|
|
.in
|
|
.IP
|
|
The lines shown for each timer have the following meanings:
|
|
.RS
|
|
.TP
|
|
.I ID
|
|
The ID for this timer.
|
|
This is not the same as the timer ID returned by
|
|
.BR timer_create (2);
|
|
rather, it is the same kernel-internal ID that is available via the
|
|
.I si_timerid
|
|
field of the
|
|
.IR siginfo_t
|
|
structure (see
|
|
.BR sigaction (2)).
|
|
.TP
|
|
.I signal
|
|
This is the signal number that this timer uses to deliver notifications
|
|
followed by a slash, and then the
|
|
.I sigev_value
|
|
value supplied to the signal handler.
|
|
Valid only for timers that notify via a signal.
|
|
.TP
|
|
.I notify
|
|
The part before the slash specifies the mechanism
|
|
that this timer uses to deliver notifications,
|
|
and is one of "thread", "signal", or "none".
|
|
Immediately following the slash is either the string "tid" for timers
|
|
with
|
|
.B SIGEV_THREAD_ID
|
|
notification, or "pid" for timers that notify by other mechanisms.
|
|
Following the "." is the PID of the process
|
|
(or the kernel thread ID of the thread) that will be delivered
|
|
a signal if the timer delivers notifications via a signal.
|
|
.TP
|
|
.I ClockID
|
|
This field identifies the clock that the timer uses for measuring time.
|
|
For most clocks, this is a number that matches one of the user-space
|
|
.BR CLOCK_*
|
|
constants exposed via
|
|
.IR <time.h> .
|
|
.B CLOCK_PROCESS_CPUTIME_ID
|
|
timers display with a value of \-6
|
|
in this field.
|
|
.B CLOCK_THREAD_CPUTIME_ID
|
|
timers display with a value of \-2
|
|
in this field.
|
|
.RE
|
|
.IP
|
|
This file is available only when the kernel was configured with
|
|
.BR CONFIG_CHECKPOINT_RESTORE .
|
|
.TP
|
|
.IR /proc/[pid]/timerslack_ns " (since Linux 4.6)"
|
|
.\" commit da8b44d5a9f8bf26da637b7336508ca534d6b319
|
|
.\" commit 5de23d435e88996b1efe0e2cebe242074ce67c9e
|
|
This file exposes the process's "current" timer slack value,
|
|
expressed in nanoseconds.
|
|
The file is writable,
|
|
allowing the process's timer slack value to be changed.
|
|
Writing 0 to this file resets the "current" timer slack to the
|
|
"default" timer slack value.
|
|
For further details, see the discussion of
|
|
.BR PR_SET_TIMERSLACK
|
|
in
|
|
.BR prctl (2).
|
|
.IP
|
|
Initially,
|
|
permission to access this file was governed by a ptrace access mode
|
|
.B PTRACE_MODE_ATTACH_FSCREDS
|
|
check (see
|
|
.BR ptrace (2)).
|
|
However, this was subsequently deemed too strict a requirement
|
|
(and had the side effect that requiring a process to have the
|
|
.B CAP_SYS_PTRACE
|
|
capability would also allow it to view and change any process's memory).
|
|
Therefore, since Linux 4.9,
|
|
.\" commit 7abbaf94049914f074306d960b0f968ffe52e59f
|
|
only the (weaker)
|
|
.B CAP_SYS_NICE
|
|
capability is required to access this file.
|
|
.TP
|
|
.IR /proc/[pid]/uid_map " (since Linux 3.5)"
|
|
See
|
|
.BR user_namespaces (7).
|
|
.TP
|
|
.IR /proc/[pid]/wchan " (since Linux 2.6.0)"
|
|
The symbolic name corresponding to the location
|
|
in the kernel where the process is sleeping.
|
|
.IP
|
|
Permission to access this file is governed by a ptrace access mode
|
|
.B PTRACE_MODE_READ_FSCREDS
|
|
check; see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/[tid]
|
|
There is a numerical subdirectory for each running thread
|
|
that is not a thread group leader
|
|
(i.e., a thread whose thread ID is not the same as its process ID);
|
|
the subdirectory is named by the thread ID.
|
|
Each one of these subdirectories contains files and subdirectories
|
|
exposing information about the thread with the thread ID
|
|
.IR tid .
|
|
The contents of these directories are the same as the corresponding
|
|
.IR /proc/[pid]/task/[tid]
|
|
directories.
|
|
.IP
|
|
The
|
|
.I /proc/[tid]
|
|
subdirectories are
|
|
.I not
|
|
visible when iterating through
|
|
.I /proc
|
|
with
|
|
.BR getdents (2)
|
|
(and thus are
|
|
.I not
|
|
visible when one uses
|
|
.BR ls (1)
|
|
to view the contents of
|
|
.IR /proc ).
|
|
However, the pathnames of these directories are visible to
|
|
(i.e., usable as arguments in)
|
|
system calls that operate on pathnames.
|
|
.TP
|
|
.I /proc/apm
|
|
Advanced power management version and battery information when
|
|
.B CONFIG_APM
|
|
is defined at kernel compilation time.
|
|
.TP
|
|
.I /proc/buddyinfo
|
|
This file contains information which is used for diagnosing memory
|
|
fragmentation issues.
|
|
Each line starts with the identification of the node and the name
|
|
of the zone which together identify a memory region.
|
|
This is then
|
|
followed by the count of available chunks of a certain order in
|
|
which these zones are split.
|
|
The size in bytes of a certain order is given by the formula:
|
|
.IP
|
|
(2^order)\ *\ PAGE_SIZE
|
|
.IP
|
|
The binary buddy allocator algorithm inside the kernel will split
|
|
one chunk into two chunks of a smaller order (thus with half the
|
|
size) or combine two contiguous chunks into one larger chunk of
|
|
a higher order (thus with double the size) to satisfy allocation
|
|
requests and to counter memory fragmentation.
|
|
The order matches the column number, when starting to count at zero.
|
|
.IP
|
|
For example on an x86-64 system:
|
|
.RS -12
|
|
.EX
|
|
Node 0, zone DMA 1 1 1 0 2 1 1 0 1 1 3
|
|
Node 0, zone DMA32 65 47 4 81 52 28 13 10 5 1 404
|
|
Node 0, zone Normal 216 55 189 101 84 38 37 27 5 3 587
|
|
.EE
|
|
.RE
|
|
.IP
|
|
In this example, there is one node containing three zones and there
|
|
are 11 different chunk sizes.
|
|
If the page size is 4 kilobytes, then the first zone called
|
|
.I DMA
|
|
(on x86 the first 16 megabyte of memory) has 1 chunk of 4 kilobytes
|
|
(order 0) available and has 3 chunks of 4 megabytes (order 10) available.
|
|
.IP
|
|
If the memory is heavily fragmented, the counters for higher
|
|
order chunks will be zero and allocation of large contiguous areas
|
|
will fail.
|
|
.IP
|
|
Further information about the zones can be found in
|
|
.IR /proc/zoneinfo .
|
|
.TP
|
|
.I /proc/bus
|
|
Contains subdirectories for installed busses.
|
|
.TP
|
|
.I /proc/bus/pccard
|
|
Subdirectory for PCMCIA devices when
|
|
.B CONFIG_PCMCIA
|
|
is set at kernel compilation time.
|
|
.TP
|
|
.I /proc/bus/pccard/drivers
|
|
.TP
|
|
.I /proc/bus/pci
|
|
Contains various bus subdirectories and pseudo-files containing
|
|
information about PCI busses, installed devices, and device
|
|
drivers.
|
|
Some of these files are not ASCII.
|
|
.TP
|
|
.I /proc/bus/pci/devices
|
|
Information about PCI devices.
|
|
They may be accessed through
|
|
.BR lspci (8)
|
|
and
|
|
.BR setpci (8).
|
|
.TP
|
|
.IR /proc/cgroups " (since Linux 2.6.24)"
|
|
See
|
|
.BR cgroups (7).
|
|
.TP
|
|
.I /proc/cmdline
|
|
Arguments passed to the Linux kernel at boot time.
|
|
Often done via a boot manager such as
|
|
.BR lilo (8)
|
|
or
|
|
.BR grub (8).
|
|
.TP
|
|
.IR /proc/config.gz " (since Linux 2.6)"
|
|
This file exposes the configuration options that were used
|
|
to build the currently running kernel,
|
|
in the same format as they would be shown in the
|
|
.I .config
|
|
file that resulted when configuring the kernel (using
|
|
.IR "make xconfig" ,
|
|
.IR "make config" ,
|
|
or similar).
|
|
The file contents are compressed; view or search them using
|
|
.BR zcat (1)
|
|
and
|
|
.BR zgrep (1).
|
|
As long as no changes have been made to the following file,
|
|
the contents of
|
|
.I /proc/config.gz
|
|
are the same as those provided by:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
cat /lib/modules/$(uname \-r)/build/.config
|
|
.EE
|
|
.in
|
|
.IP
|
|
.I /proc/config.gz
|
|
is provided only if the kernel is configured with
|
|
.BR CONFIG_IKCONFIG_PROC .
|
|
.TP
|
|
.I /proc/crypto
|
|
A list of the ciphers provided by the kernel crypto API.
|
|
For details, see the kernel
|
|
.I "Linux Kernel Crypto API"
|
|
documentation available under the kernel source directory
|
|
.I Documentation/crypto/
|
|
.\" commit 3b72c814a8e8cd638e1ba0da4dfce501e9dff5af
|
|
(or
|
|
.I Documentation/DocBook
|
|
before 4.10;
|
|
the documentation can be built using a command such as
|
|
.IR "make htmldocs"
|
|
in the root directory of the kernel source tree).
|
|
.TP
|
|
.I /proc/cpuinfo
|
|
This is a collection of CPU and system architecture dependent items,
|
|
for each supported architecture a different list.
|
|
Two common entries are \fIprocessor\fP which gives CPU number and
|
|
\fIbogomips\fP; a system constant that is calculated
|
|
during kernel initialization.
|
|
SMP machines have information for
|
|
each CPU.
|
|
The
|
|
.BR lscpu (1)
|
|
command gathers its information from this file.
|
|
.TP
|
|
.I /proc/devices
|
|
Text listing of major numbers and device groups.
|
|
This can be used by MAKEDEV scripts for consistency with the kernel.
|
|
.TP
|
|
.IR /proc/diskstats " (since Linux 2.5.69)"
|
|
This file contains disk I/O statistics for each disk device.
|
|
See the Linux kernel source file
|
|
.I ./Documentation/admin\-guide/iostats.rst
|
|
(or
|
|
.I Documentation/iostats.txt
|
|
before Linux 5.3)
|
|
for further information.
|
|
.TP
|
|
.I /proc/dma
|
|
This is a list of the registered \fIISA\fP DMA (direct memory access)
|
|
channels in use.
|
|
.TP
|
|
.I /proc/driver
|
|
Empty subdirectory.
|
|
.TP
|
|
.I /proc/execdomains
|
|
List of the execution domains (ABI personalities).
|
|
.TP
|
|
.I /proc/fb
|
|
Frame buffer information when
|
|
.B CONFIG_FB
|
|
is defined during kernel compilation.
|
|
.TP
|
|
.I /proc/filesystems
|
|
A text listing of the filesystems which are supported by the kernel,
|
|
namely filesystems which were compiled into the kernel or whose kernel
|
|
modules are currently loaded.
|
|
(See also
|
|
.BR filesystems (5).)
|
|
If a filesystem is marked with "nodev",
|
|
this means that it does not require a block device to be mounted
|
|
(e.g., virtual filesystem, network filesystem).
|
|
.IP
|
|
Incidentally, this file may be used by
|
|
.BR mount (8)
|
|
when no filesystem is specified and it didn't manage to determine the
|
|
filesystem type.
|
|
Then filesystems contained in this file are tried
|
|
(excepted those that are marked with "nodev").
|
|
.TP
|
|
.I /proc/fs
|
|
.\" FIXME Much more needs to be said about /proc/fs
|
|
.\"
|
|
Contains subdirectories that in turn contain files
|
|
with information about (certain) mounted filesystems.
|
|
.TP
|
|
.I /proc/ide
|
|
This directory
|
|
exists on systems with the IDE bus.
|
|
There are directories for each IDE channel and attached device.
|
|
Files include:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
cache buffer size in KB
|
|
capacity number of sectors
|
|
driver driver version
|
|
geometry physical and logical geometry
|
|
identify in hexadecimal
|
|
media media type
|
|
model manufacturer\(aqs model number
|
|
settings drive settings
|
|
smart_thresholds IDE disk management thresholds (in hex)
|
|
smart_values IDE disk management values (in hex)
|
|
.EE
|
|
.in
|
|
.IP
|
|
The
|
|
.BR hdparm (8)
|
|
utility provides access to this information in a friendly format.
|
|
.TP
|
|
.I /proc/interrupts
|
|
This is used to record the number of interrupts per CPU per IO device.
|
|
Since Linux 2.6.24,
|
|
for the i386 and x86-64 architectures, at least, this also includes
|
|
interrupts internal to the system (that is, not associated with a device
|
|
as such), such as NMI (nonmaskable interrupt), LOC (local timer interrupt),
|
|
and for SMP systems, TLB (TLB flush interrupt), RES (rescheduling
|
|
interrupt), CAL (remote function call interrupt), and possibly others.
|
|
Very easy to read formatting, done in ASCII.
|
|
.TP
|
|
.I /proc/iomem
|
|
I/O memory map in Linux 2.4.
|
|
.TP
|
|
.I /proc/ioports
|
|
This is a list of currently registered Input-Output port regions that
|
|
are in use.
|
|
.TP
|
|
.IR /proc/kallsyms " (since Linux 2.5.71)"
|
|
This holds the kernel exported symbol definitions used by the
|
|
.BR modules (X)
|
|
tools to dynamically link and bind loadable modules.
|
|
In Linux 2.5.47 and earlier, a similar file with slightly different syntax
|
|
was named
|
|
.IR ksyms .
|
|
.TP
|
|
.I /proc/kcore
|
|
This file represents the physical memory of the system and is stored
|
|
in the ELF core file format.
|
|
With this pseudo-file, and an unstripped
|
|
kernel
|
|
.RI ( /usr/src/linux/vmlinux )
|
|
binary, GDB can be used to
|
|
examine the current state of any kernel data structures.
|
|
.IP
|
|
The total length of the file is the size of physical memory (RAM) plus
|
|
4\ KiB.
|
|
.TP
|
|
.IR /proc/keys " (since Linux 2.6.10)"
|
|
See
|
|
.BR keyrings (7).
|
|
.TP
|
|
.IR /proc/key\-users " (since Linux 2.6.10)"
|
|
See
|
|
.BR keyrings (7).
|
|
.TP
|
|
.I /proc/kmsg
|
|
This file can be used instead of the
|
|
.BR syslog (2)
|
|
system call to read kernel messages.
|
|
A process must have superuser
|
|
privileges to read this file, and only one process should read this
|
|
file.
|
|
This file should not be read if a syslog process is running
|
|
which uses the
|
|
.BR syslog (2)
|
|
system call facility to log kernel messages.
|
|
.IP
|
|
Information in this file is retrieved with the
|
|
.BR dmesg (1)
|
|
program.
|
|
.TP
|
|
.IR /proc/kpagecgroup " (since Linux 4.3)"
|
|
.\" commit 80ae2fdceba8313b0433f899bdd9c6c463291a17
|
|
This file contains a 64-bit inode number of
|
|
the memory cgroup each page is charged to,
|
|
indexed by page frame number (see the discussion of
|
|
.IR /proc/[pid]/pagemap ).
|
|
.IP
|
|
The
|
|
.IR /proc/kpagecgroup
|
|
file is present only if the
|
|
.B CONFIG_MEMCG
|
|
kernel configuration option is enabled.
|
|
.TP
|
|
.IR /proc/kpagecount " (since Linux 2.6.25)"
|
|
This file contains a 64-bit count of the number of
|
|
times each physical page frame is mapped,
|
|
indexed by page frame number (see the discussion of
|
|
.IR /proc/[pid]/pagemap ).
|
|
.IP
|
|
The
|
|
.IR /proc/kpagecount
|
|
file is present only if the
|
|
.B CONFIG_PROC_PAGE_MONITOR
|
|
kernel configuration option is enabled.
|
|
.TP
|
|
.IR /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
|
|
.IR /proc/[pid]/pagemap ).
|
|
The bits are as follows:
|
|
.IP
|
|
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)
|
|
.\" KPF_BALLOON: commit 09316c09dde33aae14f34489d9e3d243ec0d5938
|
|
24 - KPF_ZERO_PAGE (since Linux 4.0)
|
|
.\" KPF_ZERO_PAGE: commit 56873f43abdcd574b25105867a990f067747b2f4
|
|
25 - KPF_IDLE (since Linux 4.3)
|
|
.\" KPF_IDLE: commit f074a8f49eb87cde95ac9d040ad5e7ea4f029738
|
|
.IP
|
|
For further details on the meanings of these bits,
|
|
see the kernel source file
|
|
.IR Documentation/admin\-guide/mm/pagemap.rst .
|
|
Before kernel 2.6.29,
|
|
.\" commit ad3bdefe877afb47480418fdb05ecd42842de65e
|
|
.\" commit e07a4b9217d1e97d2f3a62b6b070efdc61212110
|
|
.BR KPF_WRITEBACK ,
|
|
.BR KPF_RECLAIM ,
|
|
.BR KPF_BUDDY ,
|
|
and
|
|
.BR KPF_LOCKED
|
|
did not report correctly.
|
|
.IP
|
|
The
|
|
.IR /proc/kpageflags
|
|
file is present only if the
|
|
.B CONFIG_PROC_PAGE_MONITOR
|
|
kernel configuration option is enabled.
|
|
.TP
|
|
.IR /proc/ksyms " (Linux 1.1.23\(en2.5.47)"
|
|
See
|
|
.IR /proc/kallsyms .
|
|
.TP
|
|
.I /proc/loadavg
|
|
The first three fields in this file are load average figures
|
|
giving the number of jobs in the run queue (state R)
|
|
or waiting for disk I/O (state D) averaged over 1, 5, and 15 minutes.
|
|
They are the same as the load average numbers given by
|
|
.BR uptime (1)
|
|
and other programs.
|
|
The fourth field consists of two numbers separated by a slash (/).
|
|
The first of these is the number of currently runnable kernel
|
|
scheduling entities (processes, threads).
|
|
The value after the slash is the number of kernel scheduling entities
|
|
that currently exist on the system.
|
|
The fifth field is the PID of the process that was most
|
|
recently created on the system.
|
|
.TP
|
|
.I /proc/locks
|
|
This file shows current file locks
|
|
.RB ( flock "(2) and " fcntl (2))
|
|
and leases
|
|
.RB ( fcntl (2)).
|
|
.IP
|
|
An example of the content shown in this file is the following:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
1: POSIX ADVISORY READ 5433 08:01:7864448 128 128
|
|
2: FLOCK ADVISORY WRITE 2001 08:01:7864554 0 EOF
|
|
3: FLOCK ADVISORY WRITE 1568 00:2f:32388 0 EOF
|
|
4: POSIX ADVISORY WRITE 699 00:16:28457 0 EOF
|
|
5: POSIX ADVISORY WRITE 764 00:16:21448 0 0
|
|
6: POSIX ADVISORY READ 3548 08:01:7867240 1 1
|
|
7: POSIX ADVISORY READ 3548 08:01:7865567 1826 2335
|
|
8: OFDLCK ADVISORY WRITE \-1 08:01:8713209 128 191
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields shown in each line are as follows:
|
|
.RS
|
|
.IP (1) 4
|
|
The ordinal position of the lock in the list.
|
|
.IP (2)
|
|
The lock type.
|
|
Values that may appear here include:
|
|
.RS
|
|
.TP
|
|
.B FLOCK
|
|
This is a BSD file lock created using
|
|
.BR flock (2).
|
|
.TP
|
|
.B OFDLCK
|
|
This is an open file description (OFD) lock created using
|
|
.BR fcntl (2).
|
|
.TP
|
|
.B POSIX
|
|
This is a POSIX byte-range lock created using
|
|
.BR fcntl (2).
|
|
.RE
|
|
.IP (3)
|
|
Among the strings that can appear here are the following:
|
|
.RS
|
|
.TP
|
|
.B ADVISORY
|
|
This is an advisory lock.
|
|
.TP
|
|
.B MANDATORY
|
|
This is a mandatory lock.
|
|
.RE
|
|
.IP (4)
|
|
The type of lock.
|
|
Values that can appear here are:
|
|
.RS
|
|
.TP
|
|
.B READ
|
|
This is a POSIX or OFD read lock, or a BSD shared lock.
|
|
.TP
|
|
.B WRITE
|
|
This is a POSIX or OFD write lock, or a BSD exclusive lock.
|
|
.RE
|
|
.IP (5)
|
|
The PID of the process that owns the lock.
|
|
.IP
|
|
Because OFD locks are not owned by a single process
|
|
(since multiple processes may have file descriptors that
|
|
refer to the same open file description),
|
|
the value \-1 is displayed in this field for OFD locks.
|
|
(Before kernel 4.14,
|
|
.\" commit 9d5b86ac13c573795525ecac6ed2db39ab23e2a8
|
|
a bug meant that the PID of the process that
|
|
initially acquired the lock was displayed instead of the value \-1.)
|
|
.IP (6)
|
|
Three colon-separated subfields that identify the major and minor device
|
|
ID of the device containing the filesystem where the locked file resides,
|
|
followed by the inode number of the locked file.
|
|
.IP (7)
|
|
The byte offset of the first byte of the lock.
|
|
For BSD locks, this value is always 0.
|
|
.IP (8)
|
|
The byte offset of the last byte of the lock.
|
|
.B EOF
|
|
in this field means that the lock extends to the end of the file.
|
|
For BSD locks, the value shown is always
|
|
.IR EOF .
|
|
.RE
|
|
.IP
|
|
Since Linux 4.9,
|
|
.\" commit d67fd44f697dff293d7cdc29af929241b669affe
|
|
the list of locks shown in
|
|
.I /proc/locks
|
|
is filtered to show just the locks for the processes in the PID
|
|
namespace (see
|
|
.BR pid_namespaces (7))
|
|
for which the
|
|
.I /proc
|
|
filesystem was mounted.
|
|
(In the initial PID namespace,
|
|
there is no filtering of the records shown in this file.)
|
|
.IP
|
|
The
|
|
.BR lslocks (8)
|
|
command provides a bit more information about each lock.
|
|
.TP
|
|
.IR /proc/malloc " (only up to and including Linux 2.2)"
|
|
.\" It looks like this only ever did something back in 1.0 days
|
|
This file is present only if
|
|
.B CONFIG_DEBUG_MALLOC
|
|
was defined during compilation.
|
|
.TP
|
|
.I /proc/meminfo
|
|
This file reports statistics about memory usage on the system.
|
|
It is used by
|
|
.BR free (1)
|
|
to report the amount of free and used memory (both physical and swap)
|
|
on the system as well as the shared memory and buffers used by the
|
|
kernel.
|
|
Each line of the file consists of a parameter name, followed by a colon,
|
|
the value of the parameter, and an option unit of measurement (e.g., "kB").
|
|
The list below describes the parameter names and
|
|
the format specifier required to read the field value.
|
|
Except as noted below,
|
|
all of the fields have been present since at least Linux 2.6.0.
|
|
Some fields are displayed only if the kernel was configured
|
|
with various options; those dependencies are noted in the list.
|
|
.RS
|
|
.TP
|
|
.IR MemTotal " %lu"
|
|
Total usable RAM (i.e., physical RAM minus a few reserved
|
|
bits and the kernel binary code).
|
|
.TP
|
|
.IR MemFree " %lu"
|
|
The sum of
|
|
.IR LowFree + HighFree .
|
|
.TP
|
|
.IR MemAvailable " %lu (since Linux 3.14)"
|
|
An estimate of how much memory is available for starting new
|
|
applications, without swapping.
|
|
.TP
|
|
.IR Buffers " %lu"
|
|
Relatively temporary storage for raw disk blocks that
|
|
shouldn't get tremendously large (20 MB or so).
|
|
.TP
|
|
.IR Cached " %lu"
|
|
In-memory cache for files read from the disk (the page cache).
|
|
Doesn't include
|
|
.IR SwapCached .
|
|
.TP
|
|
.IR SwapCached " %lu"
|
|
Memory that once was swapped out, is swapped back in but
|
|
still also is in the swap file.
|
|
(If memory pressure is high, these pages
|
|
don't need to be swapped out again because they are already
|
|
in the swap file.
|
|
This saves I/O.)
|
|
.TP
|
|
.IR Active " %lu"
|
|
Memory that has been used more recently and usually not
|
|
reclaimed unless absolutely necessary.
|
|
.TP
|
|
.IR Inactive " %lu"
|
|
Memory which has been less recently used.
|
|
It is more eligible to be reclaimed for other purposes.
|
|
.TP
|
|
.IR Active(anon) " %lu (since Linux 2.6.28)"
|
|
[To be documented.]
|
|
.TP
|
|
.IR Inactive(anon) " %lu (since Linux 2.6.28)"
|
|
[To be documented.]
|
|
.TP
|
|
.IR Active(file) " %lu (since Linux 2.6.28)"
|
|
[To be documented.]
|
|
.TP
|
|
.IR Inactive(file) " %lu (since Linux 2.6.28)"
|
|
[To be documented.]
|
|
.TP
|
|
.IR Unevictable " %lu (since Linux 2.6.28)"
|
|
(From Linux 2.6.28 to 2.6.30,
|
|
\fBCONFIG_UNEVICTABLE_LRU\fP was required.)
|
|
[To be documented.]
|
|
.TP
|
|
.IR Mlocked " %lu (since Linux 2.6.28)"
|
|
(From Linux 2.6.28 to 2.6.30,
|
|
\fBCONFIG_UNEVICTABLE_LRU\fP was required.)
|
|
[To be documented.]
|
|
.TP
|
|
.IR HighTotal " %lu"
|
|
(Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.)
|
|
Total amount of highmem.
|
|
Highmem is all memory above \(ti860 MB of physical memory.
|
|
Highmem areas are for use by user-space programs,
|
|
or for the page cache.
|
|
The kernel must use tricks to access
|
|
this memory, making it slower to access than lowmem.
|
|
.TP
|
|
.IR HighFree " %lu"
|
|
(Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.)
|
|
Amount of free highmem.
|
|
.TP
|
|
.IR LowTotal " %lu"
|
|
(Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.)
|
|
Total amount of lowmem.
|
|
Lowmem is memory which can be used for everything that
|
|
highmem can be used for, but it is also available for the
|
|
kernel's use for its own data structures.
|
|
Among many other things,
|
|
it is where everything from
|
|
.I Slab
|
|
is allocated.
|
|
Bad things happen when you're out of lowmem.
|
|
.TP
|
|
.IR LowFree " %lu"
|
|
(Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.)
|
|
Amount of free lowmem.
|
|
.TP
|
|
.IR MmapCopy " %lu (since Linux 2.6.29)"
|
|
.RB ( CONFIG_MMU
|
|
is required.)
|
|
[To be documented.]
|
|
.TP
|
|
.IR SwapTotal " %lu"
|
|
Total amount of swap space available.
|
|
.TP
|
|
.IR SwapFree " %lu"
|
|
Amount of swap space that is currently unused.
|
|
.TP
|
|
.IR Dirty " %lu"
|
|
Memory which is waiting to get written back to the disk.
|
|
.TP
|
|
.IR Writeback " %lu"
|
|
Memory which is actively being written back to the disk.
|
|
.TP
|
|
.IR AnonPages " %lu (since Linux 2.6.18)"
|
|
Non-file backed pages mapped into user-space page tables.
|
|
.TP
|
|
.IR Mapped " %lu"
|
|
Files which have been mapped into memory (with
|
|
.BR mmap (2)),
|
|
such as libraries.
|
|
.TP
|
|
.IR Shmem " %lu (since Linux 2.6.32)"
|
|
Amount of memory consumed in
|
|
.BR tmpfs (5)
|
|
filesystems.
|
|
.TP
|
|
.IR KReclaimable " %lu (since Linux 4.20)"
|
|
Kernel allocations that the kernel will attempt to reclaim
|
|
under memory pressure.
|
|
Includes
|
|
.I SReclaimable
|
|
(below), and other direct allocations with a shrinker.
|
|
.TP
|
|
.IR Slab " %lu"
|
|
In-kernel data structures cache.
|
|
(See
|
|
.BR slabinfo (5).)
|
|
.TP
|
|
.IR SReclaimable " %lu (since Linux 2.6.19)"
|
|
Part of
|
|
.IR Slab ,
|
|
that might be reclaimed, such as caches.
|
|
.TP
|
|
.IR SUnreclaim " %lu (since Linux 2.6.19)"
|
|
Part of
|
|
.IR Slab ,
|
|
that cannot be reclaimed on memory pressure.
|
|
.TP
|
|
.IR KernelStack " %lu (since Linux 2.6.32)"
|
|
Amount of memory allocated to kernel stacks.
|
|
.TP
|
|
.IR PageTables " %lu (since Linux 2.6.18)"
|
|
Amount of memory dedicated to the lowest level of page tables.
|
|
.TP
|
|
.IR Quicklists " %lu (since Linux 2.6.27)"
|
|
(\fBCONFIG_QUICKLIST\fP is required.)
|
|
[To be documented.]
|
|
.TP
|
|
.IR NFS_Unstable " %lu (since Linux 2.6.18)"
|
|
NFS pages sent to the server, but not yet committed to stable storage.
|
|
.TP
|
|
.IR Bounce " %lu (since Linux 2.6.18)"
|
|
Memory used for block device "bounce buffers".
|
|
.TP
|
|
.IR WritebackTmp " %lu (since Linux 2.6.26)"
|
|
Memory used by FUSE for temporary writeback buffers.
|
|
.TP
|
|
.IR CommitLimit " %lu (since Linux 2.6.10)"
|
|
This is the total amount of memory currently available to
|
|
be allocated on the system, expressed in kilobytes.
|
|
This limit is adhered to
|
|
only if strict overcommit accounting is enabled (mode 2 in
|
|
.IR /proc/sys/vm/overcommit_memory ).
|
|
The limit is calculated according to the formula described under
|
|
.IR /proc/sys/vm/overcommit_memory .
|
|
For further details, see the kernel source file
|
|
.IR Documentation/vm/overcommit\-accounting.rst .
|
|
.TP
|
|
.IR Committed_AS " %lu"
|
|
The amount of memory presently allocated on the system.
|
|
The committed memory is a sum of all of the memory which
|
|
has been allocated by processes, even if it has not been
|
|
"used" by them as of yet.
|
|
A process which allocates 1 GB of memory (using
|
|
.BR malloc (3)
|
|
or similar), but touches only 300 MB of that memory will show up
|
|
as using only 300 MB of memory even if it has the address space
|
|
allocated for the entire 1 GB.
|
|
.IP
|
|
This 1 GB is memory which has been "committed" to by the VM
|
|
and can be used at any time by the allocating application.
|
|
With strict overcommit enabled on the system (mode 2 in
|
|
.IR /proc/sys/vm/overcommit_memory ),
|
|
allocations which would exceed the
|
|
.I CommitLimit
|
|
will not be permitted.
|
|
This is useful if one needs to guarantee that processes will not
|
|
fail due to lack of memory once that memory has been successfully allocated.
|
|
.TP
|
|
.IR VmallocTotal " %lu"
|
|
Total size of vmalloc memory area.
|
|
.TP
|
|
.IR VmallocUsed " %lu"
|
|
Amount of vmalloc area which is used.
|
|
Since Linux 4.4,
|
|
.\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0
|
|
this field is no longer calculated, and is hard coded as 0.
|
|
See
|
|
.IR /proc/vmallocinfo .
|
|
.TP
|
|
.IR VmallocChunk " %lu"
|
|
Largest contiguous block of vmalloc area which is free.
|
|
Since Linux 4.4,
|
|
.\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0
|
|
this field is no longer calculated and is hard coded as 0.
|
|
See
|
|
.IR /proc/vmallocinfo .
|
|
.TP
|
|
.IR HardwareCorrupted " %lu (since Linux 2.6.32)"
|
|
(\fBCONFIG_MEMORY_FAILURE\fP is required.)
|
|
[To be documented.]
|
|
.TP
|
|
.IR LazyFree " %lu (since Linux 4.12)"
|
|
Shows the amount of memory marked by
|
|
.BR madvise (2)
|
|
.BR MADV_FREE .
|
|
.TP
|
|
.IR AnonHugePages " %lu (since Linux 2.6.38)"
|
|
(\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.)
|
|
Non-file backed huge pages mapped into user-space page tables.
|
|
.TP
|
|
.IR ShmemHugePages " %lu (since Linux 4.8)"
|
|
(\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.)
|
|
Memory used by shared memory (shmem) and
|
|
.BR tmpfs (5)
|
|
allocated with huge pages.
|
|
.TP
|
|
.IR ShmemPmdMapped " %lu (since Linux 4.8)"
|
|
(\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.)
|
|
Shared memory mapped into user space with huge pages.
|
|
.TP
|
|
.IR CmaTotal " %lu (since Linux 3.1)"
|
|
Total CMA (Contiguous Memory Allocator) pages.
|
|
(\fBCONFIG_CMA\fP is required.)
|
|
.TP
|
|
.IR CmaFree " %lu (since Linux 3.1)"
|
|
Free CMA (Contiguous Memory Allocator) pages.
|
|
(\fBCONFIG_CMA\fP is required.)
|
|
.TP
|
|
.IR HugePages_Total " %lu"
|
|
(\fBCONFIG_HUGETLB_PAGE\fP is required.)
|
|
The size of the pool of huge pages.
|
|
.TP
|
|
.IR HugePages_Free " %lu"
|
|
(\fBCONFIG_HUGETLB_PAGE\fP is required.)
|
|
The number of huge pages in the pool that are not yet allocated.
|
|
.TP
|
|
.IR HugePages_Rsvd " %lu (since Linux 2.6.17)"
|
|
(\fBCONFIG_HUGETLB_PAGE\fP is required.)
|
|
This is the number of huge pages for
|
|
which a commitment to allocate from the pool has been made,
|
|
but no allocation has yet been made.
|
|
These reserved huge pages
|
|
guarantee that an application will be able to allocate a
|
|
huge page from the pool of huge pages at fault time.
|
|
.TP
|
|
.IR HugePages_Surp " %lu (since Linux 2.6.24)"
|
|
(\fBCONFIG_HUGETLB_PAGE\fP is required.)
|
|
This is the number of huge pages in
|
|
the pool above the value in
|
|
.IR /proc/sys/vm/nr_hugepages .
|
|
The maximum number of surplus huge pages is controlled by
|
|
.IR /proc/sys/vm/nr_overcommit_hugepages .
|
|
.TP
|
|
.IR Hugepagesize " %lu"
|
|
(\fBCONFIG_HUGETLB_PAGE\fP is required.)
|
|
The size of huge pages.
|
|
.TP
|
|
.IR DirectMap4k " %lu (since Linux 2.6.27)"
|
|
Number of bytes of RAM linearly mapped by kernel in 4 kB pages.
|
|
(x86.)
|
|
.TP
|
|
.IR DirectMap4M " %lu (since Linux 2.6.27)"
|
|
Number of bytes of RAM linearly mapped by kernel in 4 MB pages.
|
|
(x86 with
|
|
.BR CONFIG_X86_64
|
|
or
|
|
.BR CONFIG_X86_PAE
|
|
enabled.)
|
|
.TP
|
|
.IR DirectMap2M " %lu (since Linux 2.6.27)"
|
|
Number of bytes of RAM linearly mapped by kernel in 2 MB pages.
|
|
(x86 with neither
|
|
.BR CONFIG_X86_64
|
|
nor
|
|
.BR CONFIG_X86_PAE
|
|
enabled.)
|
|
.TP
|
|
.IR DirectMap1G " %lu (since Linux 2.6.27)"
|
|
(x86 with
|
|
.BR CONFIG_X86_64
|
|
and
|
|
.B CONFIG_X86_DIRECT_GBPAGES
|
|
enabled.)
|
|
.RE
|
|
.TP
|
|
.I /proc/modules
|
|
A text list of the modules that have been loaded by the system.
|
|
See also
|
|
.BR lsmod (8).
|
|
.TP
|
|
.I /proc/mounts
|
|
Before kernel 2.4.19, this file was a list
|
|
of all the filesystems currently mounted on the system.
|
|
With the introduction of per-process mount namespaces in Linux 2.4.19 (see
|
|
.BR mount_namespaces (7)),
|
|
this file became a link to
|
|
.IR /proc/self/mounts ,
|
|
which lists the mounts of the process's own mount namespace.
|
|
The format of this file is documented in
|
|
.BR fstab (5).
|
|
.TP
|
|
.I /proc/mtrr
|
|
Memory Type Range Registers.
|
|
See the Linux kernel source file
|
|
.I Documentation/x86/mtrr.rst
|
|
(or
|
|
.I Documentation/x86/mtrr.txt
|
|
.\" commit 7225e75144b9718cbbe1820d9c011c809d5773fd
|
|
before Linux 5.2, or
|
|
.I Documentation/mtrr.txt
|
|
before Linux 2.6.28)
|
|
for details.
|
|
.TP
|
|
.I /proc/net
|
|
This directory contains various files and subdirectories containing
|
|
information about the networking layer.
|
|
The files contain ASCII structures and are,
|
|
therefore, readable with
|
|
.BR cat (1).
|
|
However, the standard
|
|
.BR netstat (8)
|
|
suite provides much cleaner access to these files.
|
|
.IP
|
|
With the advent of network namespaces,
|
|
various information relating to the network stack is virtualized (see
|
|
.BR network_namespaces (7)).
|
|
Thus, since Linux 2.6.25,
|
|
.\" commit e9720acd728a46cb40daa52c99a979f7c4ff195c
|
|
.IR /proc/net
|
|
is a symbolic link to the directory
|
|
.IR /proc/self/net ,
|
|
which contains the same files and directories as listed below.
|
|
However, these files and directories now expose information
|
|
for the network namespace of which the process is a member.
|
|
.TP
|
|
.I /proc/net/arp
|
|
This holds an ASCII readable dump of the kernel ARP table used for
|
|
address resolutions.
|
|
It will show both dynamically learned and preprogrammed ARP entries.
|
|
The format is:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
IP address HW type Flags HW address Mask Device
|
|
192.168.0.50 0x1 0x2 00:50:BF:25:68:F3 * eth0
|
|
192.168.0.250 0x1 0xc 00:00:00:00:00:00 * eth0
|
|
.EE
|
|
.in
|
|
.IP
|
|
Here "IP address" is the IPv4 address of the machine and the "HW type"
|
|
is the hardware type of the address from RFC\ 826.
|
|
The flags are the internal
|
|
flags of the ARP structure (as defined in
|
|
.IR /usr/include/linux/if_arp.h )
|
|
and
|
|
the "HW address" is the data link layer mapping for that IP address if
|
|
it is known.
|
|
.TP
|
|
.I /proc/net/dev
|
|
The dev pseudo-file contains network device status information.
|
|
This gives
|
|
the number of received and sent packets, the number of errors and
|
|
collisions
|
|
and other basic statistics.
|
|
These are used by the
|
|
.BR ifconfig (8)
|
|
program to report device status.
|
|
The format is:
|
|
.IP
|
|
.EX
|
|
Inter\-| Receive | Transmit
|
|
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
|
|
lo: 2776770 11307 0 0 0 0 0 0 2776770 11307 0 0 0 0 0 0
|
|
eth0: 1215645 2751 0 0 0 0 0 0 1782404 4324 0 0 0 427 0 0
|
|
ppp0: 1622270 5552 1 0 0 0 0 0 354130 5669 0 0 0 0 0 0
|
|
tap0: 7714 81 0 0 0 0 0 0 7714 81 0 0 0 0 0 0
|
|
.EE
|
|
.\" .TP
|
|
.\" .I /proc/net/ipx
|
|
.\" No information.
|
|
.\" .TP
|
|
.\" .I /proc/net/ipx_route
|
|
.\" No information.
|
|
.TP
|
|
.I /proc/net/dev_mcast
|
|
Defined in
|
|
.IR /usr/src/linux/net/core/dev_mcast.c :
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
indx interface_name dmi_u dmi_g dmi_address
|
|
2 eth0 1 0 01005e000001
|
|
3 eth1 1 0 01005e000001
|
|
4 eth2 1 0 01005e000001
|
|
.EE
|
|
.in
|
|
.TP
|
|
.I /proc/net/igmp
|
|
Internet Group Management Protocol.
|
|
Defined in
|
|
.IR /usr/src/linux/net/core/igmp.c .
|
|
.TP
|
|
.I /proc/net/rarp
|
|
This file uses the same format as the
|
|
.I arp
|
|
file and contains the current reverse mapping database used to provide
|
|
.BR rarp (8)
|
|
reverse address lookup services.
|
|
If RARP is not configured into the
|
|
kernel,
|
|
this file will not be present.
|
|
.TP
|
|
.I /proc/net/raw
|
|
Holds a dump of the RAW socket table.
|
|
Much of the information is not of
|
|
use
|
|
apart from debugging.
|
|
The "sl" value is the kernel hash slot for the
|
|
socket,
|
|
the "local_address" is the local address and protocol number pair.
|
|
\&"St" is
|
|
the internal status of the socket.
|
|
The "tx_queue" and "rx_queue" are the
|
|
outgoing and incoming data queue in terms of kernel memory usage.
|
|
The "tr", "tm\->when", and "rexmits" fields are not used by RAW.
|
|
The "uid"
|
|
field holds the effective UID of the creator of the socket.
|
|
.\" .TP
|
|
.\" .I /proc/net/route
|
|
.\" No information, but looks similar to
|
|
.\" .BR route (8).
|
|
.TP
|
|
.I /proc/net/snmp
|
|
This file holds the ASCII data needed for the IP, ICMP, TCP, and UDP
|
|
management
|
|
information bases for an SNMP agent.
|
|
.TP
|
|
.I /proc/net/tcp
|
|
Holds a dump of the TCP socket table.
|
|
Much of the information is not
|
|
of use apart from debugging.
|
|
The "sl" value is the kernel hash slot
|
|
for the socket, the "local_address" is the local address and port number pair.
|
|
The "rem_address" is the remote address and port number pair
|
|
(if connected).
|
|
\&"St" is the internal status of the socket.
|
|
The "tx_queue" and "rx_queue" are the
|
|
outgoing and incoming data queue in terms of kernel memory usage.
|
|
The "tr", "tm\->when", and "rexmits" fields hold internal information of
|
|
the kernel socket state and are useful only for debugging.
|
|
The "uid"
|
|
field holds the effective UID of the creator of the socket.
|
|
.TP
|
|
.I /proc/net/udp
|
|
Holds a dump of the UDP socket table.
|
|
Much of the information is not of
|
|
use apart from debugging.
|
|
The "sl" value is the kernel hash slot for the
|
|
socket, the "local_address" is the local address and port number pair.
|
|
The "rem_address" is the remote address and port number pair
|
|
(if connected).
|
|
"St" is the internal status of the socket.
|
|
The "tx_queue" and "rx_queue" are the outgoing and incoming data queue
|
|
in terms of kernel memory usage.
|
|
The "tr", "tm\->when", and "rexmits" fields
|
|
are not used by UDP.
|
|
The "uid"
|
|
field holds the effective UID of the creator of the socket.
|
|
The format is:
|
|
.IP
|
|
.EX
|
|
sl local_address rem_address st tx_queue rx_queue tr rexmits tm\->when uid
|
|
1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0
|
|
1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0
|
|
1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0
|
|
.EE
|
|
.TP
|
|
.I /proc/net/unix
|
|
Lists the UNIX domain sockets present within the system and their
|
|
status.
|
|
The format is:
|
|
.IP
|
|
.EX
|
|
Num RefCount Protocol Flags Type St Inode Path
|
|
0: 00000002 00000000 00000000 0001 03 42
|
|
1: 00000001 00000000 00010000 0001 01 1948 /dev/printer
|
|
.EE
|
|
.IP
|
|
The fields are as follows:
|
|
.RS
|
|
.TP 10
|
|
.IR Num :
|
|
the kernel table slot number.
|
|
.TP
|
|
.IR RefCount :
|
|
the number of users of the socket.
|
|
.TP
|
|
.IR Protocol :
|
|
currently always 0.
|
|
.TP
|
|
.IR Flags :
|
|
the internal kernel flags holding the status of the socket.
|
|
.TP
|
|
.IR Type :
|
|
the socket type.
|
|
For
|
|
.BR SOCK_STREAM
|
|
sockets, this is 0001; for
|
|
.BR SOCK_DGRAM
|
|
sockets, it is 0002; and for
|
|
.BR SOCK_SEQPACKET
|
|
sockets, it is 0005.
|
|
.TP
|
|
.IR St :
|
|
the internal state of the socket.
|
|
.TP
|
|
.IR Inode :
|
|
the inode number of the socket.
|
|
.TP
|
|
.IR Path :
|
|
the bound pathname (if any) of the socket.
|
|
Sockets in the abstract namespace are included in the list,
|
|
and are shown with a
|
|
.I Path
|
|
that commences with the character '@'.
|
|
.RE
|
|
.TP
|
|
.I /proc/net/netfilter/nfnetlink_queue
|
|
This file contains information about netfilter user-space queueing, if used.
|
|
Each line represents a queue.
|
|
Queues that have not been subscribed to
|
|
by user space are not shown.
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
1 4207 0 2 65535 0 0 0 1
|
|
(1) (2) (3)(4) (5) (6) (7) (8)
|
|
.EE
|
|
.in
|
|
.IP
|
|
The fields in each line are:
|
|
.RS 7
|
|
.TP 5
|
|
(1)
|
|
The ID of the queue.
|
|
This matches what is specified in the
|
|
.B \-\-queue\-num
|
|
or
|
|
.B \-\-queue\-balance
|
|
options to the
|
|
.BR iptables (8)
|
|
NFQUEUE target.
|
|
See
|
|
.BR iptables\-extensions (8)
|
|
for more information.
|
|
.TP
|
|
(2)
|
|
The netlink port ID subscribed to the queue.
|
|
.TP
|
|
(3)
|
|
The number of packets currently queued and waiting to be processed by
|
|
the application.
|
|
.TP
|
|
(4)
|
|
The copy mode of the queue.
|
|
It is either 1 (metadata only) or 2
|
|
(also copy payload data to user space).
|
|
.TP
|
|
(5)
|
|
Copy range; that is, how many bytes of packet payload should be copied to
|
|
user space at most.
|
|
.TP
|
|
(6)
|
|
queue dropped.
|
|
Number of packets that had to be dropped by the kernel because
|
|
too many packets are already waiting for user space to send back the mandatory
|
|
accept/drop verdicts.
|
|
.TP
|
|
(7)
|
|
queue user dropped.
|
|
Number of packets that were dropped within the netlink
|
|
subsystem.
|
|
Such drops usually happen when the corresponding socket buffer is
|
|
full; that is, user space is not able to read messages fast enough.
|
|
.TP
|
|
(8)
|
|
sequence number.
|
|
Every queued packet is associated with a (32-bit)
|
|
monotonically increasing sequence number.
|
|
This shows the ID of the most recent packet queued.
|
|
.RE
|
|
.IP
|
|
The last number exists only for compatibility reasons and is always 1.
|
|
.TP
|
|
.I /proc/partitions
|
|
Contains the major and minor numbers of each partition as well as the number
|
|
of 1024-byte blocks and the partition name.
|
|
.TP
|
|
.I /proc/pci
|
|
This is a listing of all PCI devices found during kernel initialization
|
|
and their configuration.
|
|
.IP
|
|
This file has been deprecated in favor of a new
|
|
.I /proc
|
|
interface for PCI
|
|
.RI ( /proc/bus/pci ).
|
|
It became optional in Linux 2.2 (available with
|
|
.B CONFIG_PCI_OLD_PROC
|
|
set at kernel compilation).
|
|
It became once more nonoptionally enabled in Linux 2.4.
|
|
Next, it was deprecated in Linux 2.6 (still available with
|
|
.B CONFIG_PCI_LEGACY_PROC
|
|
set), and finally removed altogether since Linux 2.6.17.
|
|
.\" FIXME Document /proc/sched_debug (since Linux 2.6.23)
|
|
.\" See also /proc/[pid]/sched
|
|
.TP
|
|
.IR /proc/profile " (since Linux 2.4)"
|
|
This file is present only if the kernel was booted with the
|
|
.I profile=1
|
|
command-line option.
|
|
It exposes kernel profiling information in a binary format for use by
|
|
.BR readprofile (1).
|
|
Writing (e.g., an empty string) to this file resets the profiling counters;
|
|
on some architectures,
|
|
writing a binary integer "profiling multiplier" of size
|
|
.IR sizeof(int)
|
|
sets the profiling interrupt frequency.
|
|
.TP
|
|
.I /proc/scsi
|
|
A directory with the
|
|
.I scsi
|
|
mid-level pseudo-file and various SCSI low-level
|
|
driver directories,
|
|
which contain a file for each SCSI host in this system, all of
|
|
which give the status of some part of the SCSI IO subsystem.
|
|
These files contain ASCII structures and are, therefore, readable with
|
|
.BR cat (1).
|
|
.IP
|
|
You can also write to some of the files to reconfigure the subsystem or
|
|
switch certain features on or off.
|
|
.TP
|
|
.I /proc/scsi/scsi
|
|
This is a listing of all SCSI devices known to the kernel.
|
|
The listing is similar to the one seen during bootup.
|
|
scsi currently supports only the \fIadd\-single\-device\fP command which
|
|
allows root to add a hotplugged device to the list of known devices.
|
|
.IP
|
|
The command
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
echo \(aqscsi add\-single\-device 1 0 5 0\(aq > /proc/scsi/scsi
|
|
.EE
|
|
.in
|
|
.IP
|
|
will cause
|
|
host scsi1 to scan on SCSI channel 0 for a device on ID 5 LUN 0.
|
|
If there
|
|
is already a device known on this address or the address is invalid, an
|
|
error will be returned.
|
|
.TP
|
|
.I /proc/scsi/[drivername]
|
|
\fI[drivername]\fP can currently be NCR53c7xx, aha152x, aha1542, aha1740,
|
|
aic7xxx, buslogic, eata_dma, eata_pio, fdomain, in2000, pas16, qlogic,
|
|
scsi_debug, seagate, t128, u15\-24f, ultrastore, or wd7000.
|
|
These directories show up for all drivers that registered at least one
|
|
SCSI HBA.
|
|
Every directory contains one file per registered host.
|
|
Every host-file is named after the number the host was assigned during
|
|
initialization.
|
|
.IP
|
|
Reading these files will usually show driver and host configuration,
|
|
statistics, and so on.
|
|
.IP
|
|
Writing to these files allows different things on different hosts.
|
|
For example, with the \fIlatency\fP and \fInolatency\fP commands,
|
|
root can switch on and off command latency measurement code in the
|
|
eata_dma driver.
|
|
With the \fIlockup\fP and \fIunlock\fP commands,
|
|
root can control bus lockups simulated by the scsi_debug driver.
|
|
.TP
|
|
.I /proc/self
|
|
This directory refers to the process accessing the
|
|
.I /proc
|
|
filesystem,
|
|
and is identical to the
|
|
.I /proc
|
|
directory named by the process ID of the same process.
|
|
.TP
|
|
.I /proc/slabinfo
|
|
Information about kernel caches.
|
|
See
|
|
.BR slabinfo (5)
|
|
for details.
|
|
.TP
|
|
.I /proc/stat
|
|
kernel/system statistics.
|
|
Varies with architecture.
|
|
Common
|
|
entries include:
|
|
.RS
|
|
.TP
|
|
.I cpu 10132153 290696 3084719 46828483 16683 0 25195 0 175628 0
|
|
.TQ
|
|
.I cpu0 1393280 32966 572056 13343292 6130 0 17875 0 23933 0
|
|
The amount of time, measured in units of
|
|
USER_HZ (1/100ths of a second on most architectures, use
|
|
.IR sysconf(_SC_CLK_TCK)
|
|
to obtain the right value),
|
|
.\" 1024 on Alpha and ia64
|
|
that the system ("cpu" line) or the specific CPU ("cpu\fIN\fR" line)
|
|
spent in various states:
|
|
.RS
|
|
.TP
|
|
.I user
|
|
(1) Time spent in user mode.
|
|
.TP
|
|
.I nice
|
|
(2) Time spent in user mode with low priority (nice).
|
|
.TP
|
|
.I system
|
|
(3) Time spent in system mode.
|
|
.TP
|
|
.I idle
|
|
(4) Time spent in the idle task.
|
|
.\" FIXME . Actually, the following info about the /proc/stat 'cpu' field
|
|
.\" does not seem to be quite right (at least in 2.6.12 or 3.6):
|
|
.\" the idle time in /proc/uptime does not quite match this value
|
|
This value should be USER_HZ times the
|
|
second entry in the
|
|
.I /proc/uptime
|
|
pseudo-file.
|
|
.TP
|
|
.IR iowait " (since Linux 2.5.41)"
|
|
(5) Time waiting for I/O to complete.
|
|
This value is not reliable, for the following reasons:
|
|
.\" See kernel commit 9c240d757658a3ae9968dd309e674c61f07c7f48
|
|
.RS
|
|
.IP 1. 3
|
|
The CPU will not wait for I/O to complete;
|
|
iowait is the time that a task is waiting for I/O to complete.
|
|
When a CPU goes into idle state for outstanding task I/O,
|
|
another task will be scheduled on this CPU.
|
|
.IP 2.
|
|
On a multi-core CPU,
|
|
the task waiting for I/O to complete is not running on any CPU,
|
|
so the iowait of each CPU is difficult to calculate.
|
|
.IP 3.
|
|
The value in this field may
|
|
.I decrease
|
|
in certain conditions.
|
|
.RE
|
|
.TP
|
|
.IR irq " (since Linux 2.6.0)"
|
|
.\" Precisely: Linux 2.6.0-test4
|
|
(6) Time servicing interrupts.
|
|
.TP
|
|
.IR softirq " (since Linux 2.6.0)"
|
|
.\" Precisely: Linux 2.6.0-test4
|
|
(7) Time servicing softirqs.
|
|
.TP
|
|
.IR steal " (since Linux 2.6.11)"
|
|
(8) Stolen time, which is the time spent in other operating systems when
|
|
running in a virtualized environment
|
|
.TP
|
|
.IR guest " (since Linux 2.6.24)"
|
|
(9) Time spent running a virtual CPU for guest
|
|
operating systems under the control of the Linux kernel.
|
|
.\" See Changelog entry for 5e84cfde51cf303d368fcb48f22059f37b3872de
|
|
.TP
|
|
.IR guest_nice " (since Linux 2.6.33)"
|
|
.\" commit ce0e7b28fb75cb003cfc8d0238613aaf1c55e797
|
|
(10) Time spent running a niced guest (virtual CPU for guest
|
|
operating systems under the control of the Linux kernel).
|
|
.RE
|
|
.TP
|
|
\fIpage 5741 1808\fP
|
|
The number of pages the system paged in and the number that were paged
|
|
out (from disk).
|
|
.TP
|
|
\fIswap 1 0\fP
|
|
The number of swap pages that have been brought in and out.
|
|
.TP
|
|
.\" FIXME . The following is not the full picture for the 'intr' of
|
|
.\" /proc/stat on 2.6:
|
|
\fIintr 1462898\fP
|
|
This line shows counts of interrupts serviced since boot time,
|
|
for each of the possible system interrupts.
|
|
The first column is the total of all interrupts serviced
|
|
including unnumbered architecture specific interrupts;
|
|
each subsequent column is the total for that particular numbered interrupt.
|
|
Unnumbered interrupts are not shown, only summed into the total.
|
|
.TP
|
|
\fIdisk_io: (2,0):(31,30,5764,1,2) (3,0):\fP...
|
|
(major,disk_idx):(noinfo, read_io_ops, blks_read, write_io_ops, blks_written)
|
|
.br
|
|
(Linux 2.4 only)
|
|
.TP
|
|
\fIctxt 115315\fP
|
|
The number of context switches that the system underwent.
|
|
.TP
|
|
\fIbtime 769041601\fP
|
|
boot time, in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC).
|
|
.TP
|
|
\fIprocesses 86031\fP
|
|
Number of forks since boot.
|
|
.TP
|
|
\fIprocs_running 6\fP
|
|
Number of processes in runnable state.
|
|
(Linux 2.5.45 onward.)
|
|
.TP
|
|
\fIprocs_blocked 2\fP
|
|
Number of processes blocked waiting for I/O to complete.
|
|
(Linux 2.5.45 onward.)
|
|
.TP
|
|
.I softirq 229245889 94 60001584 13619 5175704 2471304 28 51212741 59130143 0 51240672
|
|
.\" commit d3d64df21d3d0de675a0d3ffa7c10514f3644b30
|
|
This line shows the number of softirq for all CPUs.
|
|
The first column is the total of all softirqs and
|
|
each subsequent column is the total for particular softirq.
|
|
(Linux 2.6.31 onward.)
|
|
.RE
|
|
.TP
|
|
.I /proc/swaps
|
|
Swap areas in use.
|
|
See also
|
|
.BR swapon (8).
|
|
.TP
|
|
.I /proc/sys
|
|
This directory (present since 1.3.57) contains a number of files
|
|
and subdirectories corresponding to kernel variables.
|
|
These variables can be read and in some cases modified using
|
|
the \fI/proc\fP filesystem, and the (deprecated)
|
|
.BR sysctl (2)
|
|
system call.
|
|
.IP
|
|
String values may be terminated by either \(aq\e0\(aq or \(aq\en\(aq.
|
|
.IP
|
|
Integer and long values may be written either in decimal or in
|
|
hexadecimal notation (e.g., 0x3FFF).
|
|
When writing multiple integer or long values, these may be separated
|
|
by any of the following whitespace characters:
|
|
\(aq\ \(aq, \(aq\et\(aq, or \(aq\en\(aq.
|
|
Using other separators leads to the error
|
|
.BR EINVAL .
|
|
.TP
|
|
.IR /proc/sys/abi " (since Linux 2.4.10)"
|
|
This directory may contain files with application binary information.
|
|
.\" On some systems, it is not present.
|
|
See the Linux kernel source file
|
|
.I Documentation/sysctl/abi.rst
|
|
(or
|
|
.I Documentation/sysctl/abi.txt
|
|
before Linux 5.3)
|
|
for more information.
|
|
.TP
|
|
.I /proc/sys/debug
|
|
This directory may be empty.
|
|
.TP
|
|
.I /proc/sys/dev
|
|
This directory contains device-specific information (e.g.,
|
|
.IR dev/cdrom/info ).
|
|
On
|
|
some systems, it may be empty.
|
|
.TP
|
|
.I /proc/sys/fs
|
|
This directory contains the files and subdirectories for kernel variables
|
|
related to filesystems.
|
|
.TP
|
|
.IR /proc/sys/fs/aio\-max\-nr " and " /proc/sys/fs/aio\-nr " (since Linux 2.6.4)"
|
|
.I aio\-nr
|
|
is the running total of the number of events specified by
|
|
.BR io_setup (2)
|
|
calls for all currently active AIO contexts.
|
|
If
|
|
.I aio\-nr
|
|
reaches
|
|
.IR aio\-max\-nr ,
|
|
then
|
|
.BR io_setup (2)
|
|
will fail with the error
|
|
.BR EAGAIN .
|
|
Raising
|
|
.I aio\-max\-nr
|
|
does not result in the preallocation or resizing
|
|
of any kernel data structures.
|
|
.TP
|
|
.I /proc/sys/fs/binfmt_misc
|
|
Documentation for files in this directory can be found
|
|
in the Linux kernel source in the file
|
|
.IR Documentation/admin\-guide/binfmt\-misc.rst
|
|
(or in
|
|
.IR Documentation/binfmt_misc.txt
|
|
on older kernels).
|
|
.TP
|
|
.IR /proc/sys/fs/dentry\-state " (since Linux 2.2)"
|
|
This file contains information about the status of the
|
|
directory cache (dcache).
|
|
The file contains six numbers,
|
|
.IR nr_dentry ", " nr_unused ", " age_limit " (age in seconds),"
|
|
.I want_pages
|
|
(pages requested by system) and two dummy values.
|
|
.RS
|
|
.IP * 2
|
|
.I nr_dentry
|
|
is the number of allocated dentries (dcache entries).
|
|
This field is unused in Linux 2.2.
|
|
.IP *
|
|
.I nr_unused
|
|
is the number of unused dentries.
|
|
.IP *
|
|
.I age_limit
|
|
.\" looks like this is unused in kernels 2.2 to 2.6
|
|
is the age in seconds after which dcache entries
|
|
can be reclaimed when memory is short.
|
|
.IP *
|
|
.I want_pages
|
|
.\" looks like this is unused in kernels 2.2 to 2.6
|
|
is nonzero when the kernel has called shrink_dcache_pages() and the
|
|
dcache isn't pruned yet.
|
|
.RE
|
|
.TP
|
|
.I /proc/sys/fs/dir\-notify\-enable
|
|
This file can be used to disable or enable the
|
|
.I dnotify
|
|
interface described in
|
|
.BR fcntl (2)
|
|
on a system-wide basis.
|
|
A value of 0 in this file disables the interface,
|
|
and a value of 1 enables it.
|
|
.TP
|
|
.I /proc/sys/fs/dquot\-max
|
|
This file shows the maximum number of cached disk quota entries.
|
|
On some (2.4) systems, it is not present.
|
|
If the number of free cached disk quota entries is very low and
|
|
you have some awesome number of simultaneous system users,
|
|
you might want to raise the limit.
|
|
.TP
|
|
.I /proc/sys/fs/dquot\-nr
|
|
This file shows the number of allocated disk quota
|
|
entries and the number of free disk quota entries.
|
|
.TP
|
|
.IR /proc/sys/fs/epoll " (since Linux 2.6.28)"
|
|
This directory contains the file
|
|
.IR max_user_watches ,
|
|
which can be used to limit the amount of kernel memory consumed by the
|
|
.I epoll
|
|
interface.
|
|
For further details, see
|
|
.BR epoll (7).
|
|
.TP
|
|
.I /proc/sys/fs/file\-max
|
|
This file defines
|
|
a system-wide limit on the number of open files for all processes.
|
|
System calls that fail when encountering this limit fail with the error
|
|
.BR ENFILE .
|
|
(See also
|
|
.BR setrlimit (2),
|
|
which can be used by a process to set the per-process limit,
|
|
.BR RLIMIT_NOFILE ,
|
|
on the number of files it may open.)
|
|
If you get lots
|
|
of error messages in the kernel log about running out of file handles
|
|
(open file descriptions)
|
|
(look for "VFS: file\-max limit <number> reached"),
|
|
try increasing this value:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
echo 100000 > /proc/sys/fs/file\-max
|
|
.EE
|
|
.in
|
|
.IP
|
|
Privileged processes
|
|
.RB ( CAP_SYS_ADMIN )
|
|
can override the
|
|
.I file\-max
|
|
limit.
|
|
.TP
|
|
.I /proc/sys/fs/file\-nr
|
|
This (read-only) file contains three numbers:
|
|
the number of allocated file handles
|
|
(i.e., the number of open file descriptions; see
|
|
.BR open (2));
|
|
the number of free file handles;
|
|
and the maximum number of file handles (i.e., the same value as
|
|
.IR /proc/sys/fs/file\-max ).
|
|
If the number of allocated file handles is close to the
|
|
maximum, you should consider increasing the maximum.
|
|
Before Linux 2.6,
|
|
the kernel allocated file handles dynamically,
|
|
but it didn't free them again.
|
|
Instead the free file handles were kept in a list for reallocation;
|
|
the "free file handles" value indicates the size of that list.
|
|
A large number of free file handles indicates that there was
|
|
a past peak in the usage of open file handles.
|
|
Since Linux 2.6, the kernel does deallocate freed file handles,
|
|
and the "free file handles" value is always zero.
|
|
.TP
|
|
.IR /proc/sys/fs/inode\-max " (only present until Linux 2.2)"
|
|
This file contains the maximum number of in-memory inodes.
|
|
This value should be 3\(en4 times larger
|
|
than the value in
|
|
.IR file\-max ,
|
|
since \fIstdin\fP, \fIstdout\fP
|
|
and network sockets also need an inode to handle them.
|
|
When you regularly run out of inodes, you need to increase this value.
|
|
.IP
|
|
Starting with Linux 2.4,
|
|
there is no longer a static limit on the number of inodes,
|
|
and this file is removed.
|
|
.TP
|
|
.I /proc/sys/fs/inode\-nr
|
|
This file contains the first two values from
|
|
.IR inode\-state .
|
|
.TP
|
|
.I /proc/sys/fs/inode\-state
|
|
This file
|
|
contains seven numbers:
|
|
.IR nr_inodes ,
|
|
.IR nr_free_inodes ,
|
|
.IR preshrink ,
|
|
and four dummy values (always zero).
|
|
.IP
|
|
.I nr_inodes
|
|
is the number of inodes the system has allocated.
|
|
.\" This can be slightly more than
|
|
.\" .I inode\-max
|
|
.\" because Linux allocates them one page full at a time.
|
|
.I nr_free_inodes
|
|
represents the number of free inodes.
|
|
.IP
|
|
.I preshrink
|
|
is nonzero when the
|
|
.I nr_inodes
|
|
>
|
|
.I inode\-max
|
|
and the system needs to prune the inode list instead of allocating more;
|
|
since Linux 2.4, this field is a dummy value (always zero).
|
|
.TP
|
|
.IR /proc/sys/fs/inotify " (since Linux 2.6.13)"
|
|
This directory contains files
|
|
.IR max_queued_events ", " max_user_instances ", and " max_user_watches ,
|
|
that can be used to limit the amount of kernel memory consumed by the
|
|
.I inotify
|
|
interface.
|
|
For further details, see
|
|
.BR inotify (7).
|
|
.TP
|
|
.I /proc/sys/fs/lease\-break\-time
|
|
This file specifies the grace period that the kernel grants to a process
|
|
holding a file lease
|
|
.RB ( fcntl (2))
|
|
after it has sent a signal to that process notifying it
|
|
that another process is waiting to open the file.
|
|
If the lease holder does not remove or downgrade the lease within
|
|
this grace period, the kernel forcibly breaks the lease.
|
|
.TP
|
|
.I /proc/sys/fs/leases\-enable
|
|
This file can be used to enable or disable file leases
|
|
.RB ( fcntl (2))
|
|
on a system-wide basis.
|
|
If this file contains the value 0, leases are disabled.
|
|
A nonzero value enables leases.
|
|
.TP
|
|
.IR /proc/sys/fs/mount\-max " (since Linux 4.9)"
|
|
.\" commit d29216842a85c7970c536108e093963f02714498
|
|
The value in this file specifies the maximum number of mounts that may exist
|
|
in a mount namespace.
|
|
The default value in this file is 100,000.
|
|
.TP
|
|
.IR /proc/sys/fs/mqueue " (since Linux 2.6.6)"
|
|
This directory contains files
|
|
.IR msg_max ", " msgsize_max ", and " queues_max ,
|
|
controlling the resources used by POSIX message queues.
|
|
See
|
|
.BR mq_overview (7)
|
|
for details.
|
|
.TP
|
|
.IR /proc/sys/fs/nr_open " (since Linux 2.6.25)"
|
|
.\" commit 9cfe015aa424b3c003baba3841a60dd9b5ad319b
|
|
This file imposes a ceiling on the value to which the
|
|
.BR RLIMIT_NOFILE
|
|
resource limit can be raised (see
|
|
.BR getrlimit (2)).
|
|
This ceiling is enforced for both unprivileged and privileged process.
|
|
The default value in this file is 1048576.
|
|
(Before Linux 2.6.25, the ceiling for
|
|
.BR RLIMIT_NOFILE
|
|
was hard-coded to the same value.)
|
|
.TP
|
|
.IR /proc/sys/fs/overflowgid " and " /proc/sys/fs/overflowuid
|
|
These files
|
|
allow you to change the value of the fixed UID and GID.
|
|
The default is 65534.
|
|
Some filesystems support only 16-bit UIDs and GIDs, although in Linux
|
|
UIDs and GIDs are 32 bits.
|
|
When one of these filesystems is mounted
|
|
with writes enabled, any UID or GID that would exceed 65535 is translated
|
|
to the overflow value before being written to disk.
|
|
.TP
|
|
.IR /proc/sys/fs/pipe\-max\-size " (since Linux 2.6.35)"
|
|
See
|
|
.BR pipe (7).
|
|
.TP
|
|
.IR /proc/sys/fs/pipe\-user\-pages\-hard " (since Linux 4.5)"
|
|
See
|
|
.BR pipe (7).
|
|
.TP
|
|
.IR /proc/sys/fs/pipe\-user\-pages\-soft " (since Linux 4.5)"
|
|
See
|
|
.BR pipe (7).
|
|
.TP
|
|
.IR /proc/sys/fs/protected_fifos " (since Linux 4.19)"
|
|
The value in this file is/can be set to one of the following:
|
|
.RS
|
|
.TP 4
|
|
0
|
|
Writing to FIFOs is unrestricted.
|
|
.TP
|
|
1
|
|
Don't allow
|
|
.B O_CREAT
|
|
.BR open (2)
|
|
on FIFOs that the caller doesn't own in world-writable sticky directories,
|
|
unless the FIFO is owned by the owner of the directory.
|
|
.TP
|
|
2
|
|
As for the value 1,
|
|
but the restriction also applies to group-writable sticky directories.
|
|
.RE
|
|
.IP
|
|
The intent of the above protections is to avoid unintentional writes to an
|
|
attacker-controlled FIFO when a program expected to create a regular file.
|
|
.TP
|
|
.IR /proc/sys/fs/protected_hardlinks " (since Linux 3.6)"
|
|
.\" commit 800179c9b8a1e796e441674776d11cd4c05d61d7
|
|
When the value in this file is 0,
|
|
no restrictions are placed on the creation of hard links
|
|
(i.e., this is the historical behavior before Linux 3.6).
|
|
When the value in this file is 1,
|
|
a hard link can be created to a target file
|
|
only if one of the following conditions is true:
|
|
.RS
|
|
.IP * 3
|
|
The calling process has the
|
|
.BR CAP_FOWNER
|
|
capability in its user namespace
|
|
and the file UID has a mapping in the namespace.
|
|
.IP *
|
|
The filesystem UID of the process creating the link matches
|
|
the owner (UID) of the target file
|
|
(as described in
|
|
.BR credentials (7),
|
|
a process's filesystem UID is normally the same as its effective UID).
|
|
.IP *
|
|
All of the following conditions are true:
|
|
.RS 4
|
|
.IP \(bu 3
|
|
the target is a regular file;
|
|
.IP \(bu
|
|
the target file does not have its set-user-ID mode bit enabled;
|
|
.IP \(bu
|
|
the target file does not have both its set-group-ID and
|
|
group-executable mode bits enabled; and
|
|
.IP \(bu
|
|
the caller has permission to read and write the target file
|
|
(either via the file's permissions mask or because it has
|
|
suitable capabilities).
|
|
.RE
|
|
.RE
|
|
.IP
|
|
The default value in this file is 0.
|
|
Setting the value to 1
|
|
prevents a longstanding class of security issues caused by
|
|
hard-link-based time-of-check, time-of-use races,
|
|
most commonly seen in world-writable directories such as
|
|
.IR /tmp .
|
|
The common method of exploiting this flaw
|
|
is to cross privilege boundaries when following a given hard link
|
|
(i.e., a root process follows a hard link created by another user).
|
|
Additionally, on systems without separated partitions,
|
|
this stops unauthorized users from "pinning" vulnerable set-user-ID and
|
|
set-group-ID files against being upgraded by
|
|
the administrator, or linking to special files.
|
|
.TP
|
|
.IR /proc/sys/fs/protected_regular " (since Linux 4.19)"
|
|
The value in this file is/can be set to one of the following:
|
|
.RS
|
|
.TP 4
|
|
0
|
|
Writing to regular files is unrestricted.
|
|
.TP
|
|
1
|
|
Don't allow
|
|
.B O_CREAT
|
|
.BR open (2)
|
|
on regular files that the caller doesn't own in
|
|
world-writable sticky directories,
|
|
unless the regular file is owned by the owner of the directory.
|
|
.TP
|
|
2
|
|
As for the value 1,
|
|
but the restriction also applies to group-writable sticky directories.
|
|
.RE
|
|
.IP
|
|
The intent of the above protections is similar to
|
|
.IR protected_fifos ,
|
|
but allows an application to
|
|
avoid writes to an attacker-controlled regular file,
|
|
where the application expected to create one.
|
|
.TP
|
|
.IR /proc/sys/fs/protected_symlinks " (since Linux 3.6)"
|
|
.\" commit 800179c9b8a1e796e441674776d11cd4c05d61d7
|
|
When the value in this file is 0,
|
|
no restrictions are placed on following symbolic links
|
|
(i.e., this is the historical behavior before Linux 3.6).
|
|
When the value in this file is 1, symbolic links are followed only
|
|
in the following circumstances:
|
|
.RS
|
|
.IP * 3
|
|
the filesystem UID of the process following the link matches
|
|
the owner (UID) of the symbolic link
|
|
(as described in
|
|
.BR credentials (7),
|
|
a process's filesystem UID is normally the same as its effective UID);
|
|
.IP *
|
|
the link is not in a sticky world-writable directory; or
|
|
.IP *
|
|
the symbolic link and its parent directory have the same owner (UID)
|
|
.RE
|
|
.IP
|
|
A system call that fails to follow a symbolic link
|
|
because of the above restrictions returns the error
|
|
.BR EACCES
|
|
in
|
|
.IR errno .
|
|
.IP
|
|
The default value in this file is 0.
|
|
Setting the value to 1 avoids a longstanding class of security issues
|
|
based on time-of-check, time-of-use races when accessing symbolic links.
|
|
.TP
|
|
.IR /proc/sys/fs/suid_dumpable " (since Linux 2.6.13)"
|
|
.\" The following is based on text from Documentation/sysctl/kernel.txt
|
|
The value in this file is assigned to a process's "dumpable" flag
|
|
in the circumstances described in
|
|
.BR prctl (2).
|
|
In effect,
|
|
the value in this file determines whether core dump files are
|
|
produced for set-user-ID or otherwise protected/tainted binaries.
|
|
The "dumpable" setting also affects the ownership of files in a process's
|
|
.IR /proc/[pid]
|
|
directory, as described above.
|
|
.IP
|
|
Three different integer values can be specified:
|
|
.RS
|
|
.TP
|
|
\fI0\ (default)\fP
|
|
.\" In kernel source: SUID_DUMP_DISABLE
|
|
This provides the traditional (pre-Linux 2.6.13) behavior.
|
|
A core dump will not be produced for a process which has
|
|
changed credentials (by calling
|
|
.BR seteuid (2),
|
|
.BR setgid (2),
|
|
or similar, or by executing a set-user-ID or set-group-ID program)
|
|
or whose binary does not have read permission enabled.
|
|
.TP
|
|
\fI1\ ("debug")\fP
|
|
.\" In kernel source: SUID_DUMP_USER
|
|
All processes dump core when possible.
|
|
(Reasons why a process might nevertheless not dump core are described in
|
|
.BR core (5).)
|
|
The core dump is owned by the filesystem user ID of the dumping process
|
|
and no security is applied.
|
|
This is intended for system debugging situations only:
|
|
this mode is insecure because it allows unprivileged users to
|
|
examine the memory contents of privileged processes.
|
|
.TP
|
|
\fI2\ ("suidsafe")\fP
|
|
.\" In kernel source: SUID_DUMP_ROOT
|
|
Any binary which normally would not be dumped (see "0" above)
|
|
is dumped readable by root only.
|
|
This allows the user to remove the core dump file but not to read it.
|
|
For security reasons core dumps in this mode will not overwrite one
|
|
another or other files.
|
|
This mode is appropriate when administrators are
|
|
attempting to debug problems in a normal environment.
|
|
.IP
|
|
Additionally, since Linux 3.6,
|
|
.\" 9520628e8ceb69fa9a4aee6b57f22675d9e1b709
|
|
.I /proc/sys/kernel/core_pattern
|
|
must either be an absolute pathname
|
|
or a pipe command, as detailed in
|
|
.BR core (5).
|
|
Warnings will be written to the kernel log if
|
|
.I core_pattern
|
|
does not follow these rules, and no core dump will be produced.
|
|
.\" 54b501992dd2a839e94e76aa392c392b55080ce8
|
|
.RE
|
|
.IP
|
|
For details of the effect of a process's "dumpable" setting
|
|
on ptrace access mode checking, see
|
|
.BR ptrace (2).
|
|
.TP
|
|
.I /proc/sys/fs/super\-max
|
|
This file
|
|
controls the maximum number of superblocks, and
|
|
thus the maximum number of mounted filesystems the kernel
|
|
can have.
|
|
You need increase only
|
|
.I super\-max
|
|
if you need to mount more filesystems than the current value in
|
|
.I super\-max
|
|
allows you to.
|
|
.TP
|
|
.I /proc/sys/fs/super\-nr
|
|
This file
|
|
contains the number of filesystems currently mounted.
|
|
.TP
|
|
.I /proc/sys/kernel
|
|
This directory contains files controlling a range of kernel parameters,
|
|
as described below.
|
|
.TP
|
|
.I /proc/sys/kernel/acct
|
|
This file
|
|
contains three numbers:
|
|
.IR highwater ,
|
|
.IR lowwater ,
|
|
and
|
|
.IR frequency .
|
|
If BSD-style process accounting is enabled, these values control
|
|
its behavior.
|
|
If free space on filesystem where the log lives goes below
|
|
.I lowwater
|
|
percent, accounting suspends.
|
|
If free space gets above
|
|
.I highwater
|
|
percent, accounting resumes.
|
|
.I frequency
|
|
determines
|
|
how often the kernel checks the amount of free space (value is in
|
|
seconds).
|
|
Default values are 4, 2, and 30.
|
|
That is, suspend accounting if 2% or less space is free; resume it
|
|
if 4% or more space is free; consider information about amount of free space
|
|
valid for 30 seconds.
|
|
.TP
|
|
.IR /proc/sys/kernel/auto_msgmni " (Linux 2.6.27 to 3.18)"
|
|
.\" commit 9eefe520c814f6f62c5d36a2ddcd3fb99dfdb30e (introduces feature)
|
|
.\" commit 0050ee059f7fc86b1df2527aaa14ed5dc72f9973 (rendered redundant)
|
|
From Linux 2.6.27 to 3.18,
|
|
this file was used to control recomputing of the value in
|
|
.IR /proc/sys/kernel/msgmni
|
|
upon the addition or removal of memory or upon IPC namespace creation/removal.
|
|
Echoing "1" into this file enabled
|
|
.I msgmni
|
|
automatic recomputing (and triggered a recomputation of
|
|
.I msgmni
|
|
based on the current amount of available memory and number of IPC namespaces).
|
|
Echoing "0" disabled automatic recomputing.
|
|
(Automatic recomputing was also disabled if a value was explicitly assigned to
|
|
.IR /proc/sys/kernel/msgmni .)
|
|
The default value in
|
|
.I auto_msgmni
|
|
was 1.
|
|
.IP
|
|
Since Linux 3.19, the content of this file has no effect (because
|
|
.IR msgmni
|
|
.\" FIXME Must document the 3.19 'msgmni' changes.
|
|
defaults to near the maximum value possible),
|
|
and reads from this file always return the value "0".
|
|
.TP
|
|
.IR /proc/sys/kernel/cap_last_cap " (since Linux 3.2)"
|
|
See
|
|
.BR capabilities (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/cap\-bound " (from Linux 2.2 to 2.6.24)"
|
|
This file holds the value of the kernel
|
|
.I "capability bounding set"
|
|
(expressed as a signed decimal number).
|
|
This set is ANDed against the capabilities permitted to a process
|
|
during
|
|
.BR execve (2).
|
|
Starting with Linux 2.6.25,
|
|
the system-wide capability bounding set disappeared,
|
|
and was replaced by a per-thread bounding set; see
|
|
.BR capabilities (7).
|
|
.TP
|
|
.I /proc/sys/kernel/core_pattern
|
|
See
|
|
.BR core (5).
|
|
.TP
|
|
.I /proc/sys/kernel/core_pipe_limit
|
|
See
|
|
.BR core (5).
|
|
.TP
|
|
.I /proc/sys/kernel/core_uses_pid
|
|
See
|
|
.BR core (5).
|
|
.TP
|
|
.I /proc/sys/kernel/ctrl\-alt\-del
|
|
This file
|
|
controls the handling of Ctrl-Alt-Del from the keyboard.
|
|
When the value in this file is 0, Ctrl-Alt-Del is trapped and
|
|
sent to the
|
|
.BR init (1)
|
|
program to handle a graceful restart.
|
|
When the value is greater than zero, Linux's reaction to a Vulcan
|
|
Nerve Pinch (tm) will be an immediate reboot, without even
|
|
syncing its dirty buffers.
|
|
Note: when a program (like dosemu) has the keyboard in "raw"
|
|
mode, the ctrl-alt-del is intercepted by the program before it
|
|
ever reaches the kernel tty layer, and it's up to the program
|
|
to decide what to do with it.
|
|
.TP
|
|
.IR /proc/sys/kernel/dmesg_restrict " (since Linux 2.6.37)"
|
|
The value in this file determines who can see kernel syslog contents.
|
|
A value of 0 in this file imposes no restrictions.
|
|
If the value is 1, only privileged users can read the kernel syslog.
|
|
(See
|
|
.BR syslog (2)
|
|
for more details.)
|
|
Since Linux 3.4,
|
|
.\" commit 620f6e8e855d6d447688a5f67a4e176944a084e8
|
|
only users with the
|
|
.BR CAP_SYS_ADMIN
|
|
capability may change the value in this file.
|
|
.TP
|
|
.IR /proc/sys/kernel/domainname " and " /proc/sys/kernel/hostname
|
|
can be used to set the NIS/YP domainname and the
|
|
hostname of your box in exactly the same way as the commands
|
|
.BR domainname (1)
|
|
and
|
|
.BR hostname (1),
|
|
that is:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "#" " echo \(aqdarkstar\(aq > /proc/sys/kernel/hostname"
|
|
.RB "#" " echo \(aqmydomain\(aq > /proc/sys/kernel/domainname"
|
|
.EE
|
|
.in
|
|
.IP
|
|
has the same effect as
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB "#" " hostname \(aqdarkstar\(aq"
|
|
.RB "#" " domainname \(aqmydomain\(aq"
|
|
.EE
|
|
.in
|
|
.IP
|
|
Note, however, that the classic darkstar.frop.org has the
|
|
hostname "darkstar" and DNS (Internet Domain Name Server)
|
|
domainname "frop.org", not to be confused with the NIS (Network
|
|
Information Service) or YP (Yellow Pages) domainname.
|
|
These two
|
|
domain names are in general different.
|
|
For a detailed discussion
|
|
see the
|
|
.BR hostname (1)
|
|
man page.
|
|
.TP
|
|
.I /proc/sys/kernel/hotplug
|
|
This file
|
|
contains the pathname for the hotplug policy agent.
|
|
The default value in this file is
|
|
.IR /sbin/hotplug .
|
|
.TP
|
|
.\" Removed in commit 87f504e5c78b910b0c1d6ffb89bc95e492322c84 (tglx/history.git)
|
|
.IR /proc/sys/kernel/htab\-reclaim " (before Linux 2.4.9.2)"
|
|
(PowerPC only) If this file is set to a nonzero value,
|
|
the PowerPC htab
|
|
.\" removed in commit 1b483a6a7b2998e9c98ad985d7494b9b725bd228, before 2.6.28
|
|
(see kernel file
|
|
.IR Documentation/powerpc/ppc_htab.txt )
|
|
is pruned
|
|
each time the system hits the idle loop.
|
|
.TP
|
|
.IR /proc/sys/kernel/keys/*
|
|
This directory contains various files that define parameters and limits
|
|
for the key-management facility.
|
|
These files are described in
|
|
.BR keyrings (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/kptr_restrict " (since Linux 2.6.38)"
|
|
.\" 455cd5ab305c90ffc422dd2e0fb634730942b257
|
|
The value in this file determines whether kernel addresses are exposed via
|
|
.I /proc
|
|
files and other interfaces.
|
|
A value of 0 in this file imposes no restrictions.
|
|
If the value is 1, kernel pointers printed using the
|
|
.I %pK
|
|
format specifier will be replaced with zeros unless the user has the
|
|
.BR CAP_SYSLOG
|
|
capability.
|
|
If the value is 2, kernel pointers printed using the
|
|
.I %pK
|
|
format specifier will be replaced with zeros regardless
|
|
of the user's capabilities.
|
|
The initial default value for this file was 1,
|
|
but the default was changed
|
|
.\" commit 411f05f123cbd7f8aa1edcae86970755a6e2a9d9
|
|
to 0 in Linux 2.6.39.
|
|
Since Linux 3.4,
|
|
.\" commit 620f6e8e855d6d447688a5f67a4e176944a084e8
|
|
only users with the
|
|
.BR CAP_SYS_ADMIN
|
|
capability can change the value in this file.
|
|
.TP
|
|
.I /proc/sys/kernel/l2cr
|
|
(PowerPC only) This file
|
|
contains a flag that controls the L2 cache of G3 processor
|
|
boards.
|
|
If 0, the cache is disabled.
|
|
Enabled if nonzero.
|
|
.TP
|
|
.I /proc/sys/kernel/modprobe
|
|
This file contains the pathname for the kernel module loader.
|
|
The default value is
|
|
.IR /sbin/modprobe .
|
|
The file is present only if the kernel is built with the
|
|
.B CONFIG_MODULES
|
|
.RB ( CONFIG_KMOD
|
|
in Linux 2.6.26 and earlier)
|
|
option enabled.
|
|
It is described by the Linux kernel source file
|
|
.I Documentation/kmod.txt
|
|
(present only in kernel 2.4 and earlier).
|
|
.TP
|
|
.IR /proc/sys/kernel/modules_disabled " (since Linux 2.6.31)"
|
|
.\" 3d43321b7015387cfebbe26436d0e9d299162ea1
|
|
.\" From Documentation/sysctl/kernel.txt
|
|
A toggle value indicating if modules are allowed to be loaded
|
|
in an otherwise modular kernel.
|
|
This toggle defaults to off (0), but can be set true (1).
|
|
Once true, modules can be neither loaded nor unloaded,
|
|
and the toggle cannot be set back to false.
|
|
The file is present only if the kernel is built with the
|
|
.B CONFIG_MODULES
|
|
option enabled.
|
|
.TP
|
|
.IR /proc/sys/kernel/msgmax " (since Linux 2.2)"
|
|
This file defines
|
|
a system-wide limit specifying the maximum number of bytes in
|
|
a single message written on a System V message queue.
|
|
.TP
|
|
.IR /proc/sys/kernel/msgmni " (since Linux 2.4)"
|
|
This file defines the system-wide limit on the number of
|
|
message queue identifiers.
|
|
See also
|
|
.IR /proc/sys/kernel/auto_msgmni .
|
|
.TP
|
|
.IR /proc/sys/kernel/msgmnb " (since Linux 2.2)"
|
|
This file defines a system-wide parameter used to initialize the
|
|
.I msg_qbytes
|
|
setting for subsequently created message queues.
|
|
The
|
|
.I msg_qbytes
|
|
setting specifies the maximum number of bytes that may be written to the
|
|
message queue.
|
|
.TP
|
|
.IR /proc/sys/kernel/ngroups_max " (since Linux 2.6.4)"
|
|
This is a read-only file that displays the upper limit on the
|
|
number of a process's group memberships.
|
|
.TP
|
|
.IR /proc/sys/kernel/ns_last_pid " (since Linux 3.3)"
|
|
See
|
|
.BR pid_namespaces (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/ostype " and " /proc/sys/kernel/osrelease
|
|
These files
|
|
give substrings of
|
|
.IR /proc/version .
|
|
.TP
|
|
.IR /proc/sys/kernel/overflowgid " and " /proc/sys/kernel/overflowuid
|
|
These files duplicate the files
|
|
.I /proc/sys/fs/overflowgid
|
|
and
|
|
.IR /proc/sys/fs/overflowuid .
|
|
.TP
|
|
.I /proc/sys/kernel/panic
|
|
This file gives read/write access to the kernel variable
|
|
.IR panic_timeout .
|
|
If this is zero, the kernel will loop on a panic; if nonzero,
|
|
it indicates that the kernel should autoreboot after this number
|
|
of seconds.
|
|
When you use the
|
|
software watchdog device driver, the recommended setting is 60.
|
|
.TP
|
|
.IR /proc/sys/kernel/panic_on_oops " (since Linux 2.5.68)"
|
|
This file controls the kernel's behavior when an oops
|
|
or BUG is encountered.
|
|
If this file contains 0, then the system
|
|
tries to continue operation.
|
|
If it contains 1, then the system
|
|
delays a few seconds (to give klogd time to record the oops output)
|
|
and then panics.
|
|
If the
|
|
.I /proc/sys/kernel/panic
|
|
file is also nonzero, then the machine will be rebooted.
|
|
.TP
|
|
.IR /proc/sys/kernel/pid_max " (since Linux 2.5.34)"
|
|
This file specifies the value at which PIDs wrap around
|
|
(i.e., the value in this file is one greater than the maximum PID).
|
|
PIDs greater than this value are not allocated;
|
|
thus, the value in this file also acts as a system-wide limit
|
|
on the total number of processes and threads.
|
|
The default value for this file, 32768,
|
|
results in the same range of PIDs as on earlier kernels.
|
|
On 32-bit platforms, 32768 is the maximum value for
|
|
.IR pid_max .
|
|
On 64-bit systems,
|
|
.I pid_max
|
|
can be set to any value up to 2^22
|
|
.RB ( PID_MAX_LIMIT ,
|
|
approximately 4 million).
|
|
.\" Prior to 2.6.10, pid_max could also be raised above 32768 on 32-bit
|
|
.\" platforms, but this broke /proc/[pid]
|
|
.\" See http://marc.theaimsgroup.com/?l=linux-kernel&m=109513010926152&w=2
|
|
.TP
|
|
.IR /proc/sys/kernel/powersave\-nap " (PowerPC only)"
|
|
This file contains a flag.
|
|
If set, Linux-PPC will use the "nap" mode of
|
|
powersaving,
|
|
otherwise the "doze" mode will be used.
|
|
.TP
|
|
.I /proc/sys/kernel/printk
|
|
See
|
|
.BR syslog (2).
|
|
.TP
|
|
.IR /proc/sys/kernel/pty " (since Linux 2.6.4)"
|
|
This directory contains two files relating to the number of UNIX 98
|
|
pseudoterminals (see
|
|
.BR pts (4))
|
|
on the system.
|
|
.TP
|
|
.I /proc/sys/kernel/pty/max
|
|
This file defines the maximum number of pseudoterminals.
|
|
.\" FIXME Document /proc/sys/kernel/pty/reserve
|
|
.\" New in Linux 3.3
|
|
.\" commit e9aba5158a80098447ff207a452a3418ae7ee386
|
|
.TP
|
|
.I /proc/sys/kernel/pty/nr
|
|
This read-only file
|
|
indicates how many pseudoterminals are currently in use.
|
|
.TP
|
|
.I /proc/sys/kernel/random
|
|
This directory
|
|
contains various parameters controlling the operation of the file
|
|
.IR /dev/random .
|
|
See
|
|
.BR random (4)
|
|
for further information.
|
|
.TP
|
|
.IR /proc/sys/kernel/random/uuid " (since Linux 2.4)"
|
|
Each read from this read-only file returns a randomly generated 128-bit UUID,
|
|
as a string in the standard UUID format.
|
|
.TP
|
|
.IR /proc/sys/kernel/randomize_va_space " (since Linux 2.6.12)"
|
|
.\" Some further details can be found in Documentation/sysctl/kernel.txt
|
|
Select the address space layout randomization (ASLR) policy for the system
|
|
(on architectures that support ASLR).
|
|
Three values are supported for this file:
|
|
.RS
|
|
.IP 0 3
|
|
Turn ASLR off.
|
|
This is the default for architectures that don't support ASLR,
|
|
and when the kernel is booted with the
|
|
.I norandmaps
|
|
parameter.
|
|
.IP 1
|
|
Make the addresses of
|
|
.BR mmap (2)
|
|
allocations, the stack, and the VDSO page randomized.
|
|
Among other things, this means that shared libraries will be
|
|
loaded at randomized addresses.
|
|
The text segment of PIE-linked binaries will also be loaded
|
|
at a randomized address.
|
|
This value is the default if the kernel was configured with
|
|
.BR CONFIG_COMPAT_BRK .
|
|
.IP 2
|
|
(Since Linux 2.6.25)
|
|
.\" commit c1d171a002942ea2d93b4fbd0c9583c56fce0772
|
|
Also support heap randomization.
|
|
This value is the default if the kernel was not configured with
|
|
.BR CONFIG_COMPAT_BRK .
|
|
.RE
|
|
.TP
|
|
.I /proc/sys/kernel/real\-root\-dev
|
|
This file is documented in the Linux kernel source file
|
|
.I Documentation/admin\-guide/initrd.rst
|
|
.\" commit 9d85025b0418163fae079c9ba8f8445212de8568
|
|
(or
|
|
.I Documentation/initrd.txt
|
|
before Linux 4.10).
|
|
.TP
|
|
.IR /proc/sys/kernel/reboot\-cmd " (Sparc only)"
|
|
This file seems to be a way to give an argument to the SPARC
|
|
ROM/Flash boot loader.
|
|
Maybe to tell it what to do after
|
|
rebooting?
|
|
.TP
|
|
.I /proc/sys/kernel/rtsig\-max
|
|
(Only in kernels up to and including 2.6.7; see
|
|
.BR setrlimit (2))
|
|
This file can be used to tune the maximum number
|
|
of POSIX real-time (queued) signals that can be outstanding
|
|
in the system.
|
|
.TP
|
|
.I /proc/sys/kernel/rtsig\-nr
|
|
(Only in kernels up to and including 2.6.7.)
|
|
This file shows the number of POSIX real-time signals currently queued.
|
|
.TP
|
|
.IR /proc/[pid]/sched_autogroup_enabled " (since Linux 2.6.38)"
|
|
.\" commit 5091faa449ee0b7d73bc296a93bca9540fc51d0a
|
|
See
|
|
.BR sched (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/sched_child_runs_first " (since Linux 2.6.23)"
|
|
If this file contains the value zero, then, after a
|
|
.BR fork (2),
|
|
the parent is first scheduled on the CPU.
|
|
If the file contains a nonzero value,
|
|
then the child is scheduled first on the CPU.
|
|
(Of course, on a multiprocessor system,
|
|
the parent and the child might both immediately be scheduled on a CPU.)
|
|
.TP
|
|
.IR /proc/sys/kernel/sched_rr_timeslice_ms " (since Linux 3.9)"
|
|
See
|
|
.BR sched_rr_get_interval (2).
|
|
.TP
|
|
.IR /proc/sys/kernel/sched_rt_period_us " (since Linux 2.6.25)"
|
|
See
|
|
.BR sched (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/sched_rt_runtime_us " (since Linux 2.6.25)"
|
|
See
|
|
.BR sched (7).
|
|
.TP
|
|
.IR /proc/sys/kernel/seccomp " (since Linux 4.14)"
|
|
.\" commit 8e5f1ad116df6b0de65eac458d5e7c318d1c05af
|
|
This directory provides additional seccomp information and
|
|
configuration.
|
|
See
|
|
.BR seccomp (2)
|
|
for further details.
|
|
.TP
|
|
.IR /proc/sys/kernel/sem " (since Linux 2.4)"
|
|
This file contains 4 numbers defining limits for System V IPC semaphores.
|
|
These fields are, in order:
|
|
.RS
|
|
.IP SEMMSL 8
|
|
The maximum semaphores per semaphore set.
|
|
.IP SEMMNS 8
|
|
A system-wide limit on the number of semaphores in all semaphore sets.
|
|
.IP SEMOPM 8
|
|
The maximum number of operations that may be specified in a
|
|
.BR semop (2)
|
|
call.
|
|
.IP SEMMNI 8
|
|
A system-wide limit on the maximum number of semaphore identifiers.
|
|
.RE
|
|
.TP
|
|
.I /proc/sys/kernel/sg\-big\-buff
|
|
This file
|
|
shows the size of the generic SCSI device (sg) buffer.
|
|
You can't tune it just yet, but you could change it at
|
|
compile time by editing
|
|
.I include/scsi/sg.h
|
|
and changing
|
|
the value of
|
|
.BR SG_BIG_BUFF .
|
|
However, there shouldn't be any reason to change this value.
|
|
.TP
|
|
.IR /proc/sys/kernel/shm_rmid_forced " (since Linux 3.1)"
|
|
.\" commit b34a6b1da371ed8af1221459a18c67970f7e3d53
|
|
.\" See also Documentation/sysctl/kernel.txt
|
|
If this file is set to 1, all System V shared memory segments will
|
|
be marked for destruction as soon as the number of attached processes
|
|
falls to zero;
|
|
in other words, it is no longer possible to create shared memory segments
|
|
that exist independently of any attached process.
|
|
.IP
|
|
The effect is as though a
|
|
.BR shmctl (2)
|
|
.B IPC_RMID
|
|
is performed on all existing segments as well as all segments
|
|
created in the future (until this file is reset to 0).
|
|
Note that existing segments that are attached to no process will be
|
|
immediately destroyed when this file is set to 1.
|
|
Setting this option will also destroy segments that were created,
|
|
but never attached,
|
|
upon termination of the process that created the segment with
|
|
.BR shmget (2).
|
|
.IP
|
|
Setting this file to 1 provides a way of ensuring that
|
|
all System V shared memory segments are counted against the
|
|
resource usage and resource limits (see the description of
|
|
.B RLIMIT_AS
|
|
in
|
|
.BR getrlimit (2))
|
|
of at least one process.
|
|
.IP
|
|
Because setting this file to 1 produces behavior that is nonstandard
|
|
and could also break existing applications,
|
|
the default value in this file is 0.
|
|
Set this file to 1 only if you have a good understanding
|
|
of the semantics of the applications using
|
|
System V shared memory on your system.
|
|
.TP
|
|
.IR /proc/sys/kernel/shmall " (since Linux 2.2)"
|
|
This file
|
|
contains the system-wide limit on the total number of pages of
|
|
System V shared memory.
|
|
.TP
|
|
.IR /proc/sys/kernel/shmmax " (since Linux 2.2)"
|
|
This file
|
|
can be used to query and set the run-time limit
|
|
on the maximum (System V IPC) shared memory segment size that can be
|
|
created.
|
|
Shared memory segments up to 1 GB are now supported in the
|
|
kernel.
|
|
This value defaults to
|
|
.BR SHMMAX .
|
|
.TP
|
|
.IR /proc/sys/kernel/shmmni " (since Linux 2.4)"
|
|
This file
|
|
specifies the system-wide maximum number of System V shared memory
|
|
segments that can be created.
|
|
.TP
|
|
.IR /proc/sys/kernel/sysctl_writes_strict " (since Linux 3.16)"
|
|
.\" commit f88083005ab319abba5d0b2e4e997558245493c8
|
|
.\" commit 2ca9bb456ada8bcbdc8f77f8fc78207653bbaa92
|
|
.\" commit f4aacea2f5d1a5f7e3154e967d70cf3f711bcd61
|
|
.\" commit 24fe831c17ab8149413874f2fd4e5c8a41fcd294
|
|
The value in this file determines how the file offset affects
|
|
the behavior of updating entries in files under
|
|
.IR /proc/sys .
|
|
The file has three possible values:
|
|
.RS
|
|
.TP 4
|
|
\-1
|
|
This provides legacy handling, with no printk warnings.
|
|
Each
|
|
.BR write (2)
|
|
must fully contain the value to be written,
|
|
and multiple writes on the same file descriptor
|
|
will overwrite the entire value, regardless of the file position.
|
|
.TP
|
|
0
|
|
(default) This provides the same behavior as for \-1,
|
|
but printk warnings are written for processes that
|
|
perform writes when the file offset is not 0.
|
|
.TP
|
|
1
|
|
Respect the file offset when writing strings into
|
|
.I /proc/sys
|
|
files.
|
|
Multiple writes will
|
|
.I append
|
|
to the value buffer.
|
|
Anything written beyond the maximum length
|
|
of the value buffer will be ignored.
|
|
Writes to numeric
|
|
.I /proc/sys
|
|
entries must always be at file offset 0 and the value must be
|
|
fully contained in the buffer provided to
|
|
.BR write (2).
|
|
.\" FIXME .
|
|
.\" With /proc/sys/kernel/sysctl_writes_strict==1, writes at an
|
|
.\" offset other than 0 do not generate an error. Instead, the
|
|
.\" write() succeeds, but the file is left unmodified.
|
|
.\" This is surprising. The behavior may change in the future.
|
|
.\" See thread.gmane.org/gmane.linux.man/9197
|
|
.\" From: Michael Kerrisk (man-pages <mtk.manpages@...>
|
|
.\" Subject: sysctl_writes_strict documentation + an oddity?
|
|
.\" Newsgroups: gmane.linux.man, gmane.linux.kernel
|
|
.\" Date: 2015-05-09 08:54:11 GMT
|
|
.RE
|
|
.TP
|
|
.I /proc/sys/kernel/sysrq
|
|
This file controls the functions allowed to be invoked by the SysRq key.
|
|
By default,
|
|
the file contains 1 meaning that every possible SysRq request is allowed
|
|
(in older kernel versions, SysRq was disabled by default,
|
|
and you were required to specifically enable it at run-time,
|
|
but this is not the case any more).
|
|
Possible values in this file are:
|
|
.RS
|
|
.TP 5
|
|
0
|
|
Disable sysrq completely
|
|
.TP
|
|
1
|
|
Enable all functions of sysrq
|
|
.TP
|
|
> 1
|
|
Bit mask of allowed sysrq functions, as follows:
|
|
.PD 0
|
|
.RS
|
|
.TP 5
|
|
\ \ 2
|
|
Enable control of console logging level
|
|
.TP
|
|
\ \ 4
|
|
Enable control of keyboard (SAK, unraw)
|
|
.TP
|
|
\ \ 8
|
|
Enable debugging dumps of processes etc.
|
|
.TP
|
|
\ 16
|
|
Enable sync command
|
|
.TP
|
|
\ 32
|
|
Enable remount read-only
|
|
.TP
|
|
\ 64
|
|
Enable signaling of processes (term, kill, oom-kill)
|
|
.TP
|
|
128
|
|
Allow reboot/poweroff
|
|
.TP
|
|
256
|
|
Allow nicing of all real-time tasks
|
|
.RE
|
|
.PD
|
|
.RE
|
|
.IP
|
|
This file is present only if the
|
|
.B CONFIG_MAGIC_SYSRQ
|
|
kernel configuration option is enabled.
|
|
For further details see the Linux kernel source file
|
|
.I Documentation/admin\-guide/sysrq.rst
|
|
.\" commit 9d85025b0418163fae079c9ba8f8445212de8568
|
|
(or
|
|
.I Documentation/sysrq.txt
|
|
before Linux 4.10).
|
|
.TP
|
|
.I /proc/sys/kernel/version
|
|
This file contains a string such as:
|
|
.IP
|
|
#5 Wed Feb 25 21:49:24 MET 1998
|
|
.IP
|
|
The "#5" means that
|
|
this is the fifth kernel built from this source base and the
|
|
date following it indicates the time the kernel was built.
|
|
.TP
|
|
.IR /proc/sys/kernel/threads\-max " (since Linux 2.3.11)"
|
|
.\" The following is based on Documentation/sysctl/kernel.txt
|
|
This file specifies the system-wide limit on the number of
|
|
threads (tasks) that can be created on the system.
|
|
.IP
|
|
Since Linux 4.1,
|
|
.\" commit 230633d109e35b0a24277498e773edeb79b4a331
|
|
the value that can be written to
|
|
.I threads\-max
|
|
is bounded.
|
|
The minimum value that can be written is 20.
|
|
The maximum value that can be written is given by the
|
|
constant
|
|
.B FUTEX_TID_MASK
|
|
(0x3fffffff).
|
|
If a value outside of this range is written to
|
|
.IR threads\-max ,
|
|
the error
|
|
.B EINVAL
|
|
occurs.
|
|
.IP
|
|
The value written is checked against the available RAM pages.
|
|
If the thread structures would occupy too much (more than 1/8th)
|
|
of the available RAM pages,
|
|
.I threads\-max
|
|
is reduced accordingly.
|
|
.TP
|
|
.IR /proc/sys/kernel/yama/ptrace_scope " (since Linux 3.5)"
|
|
See
|
|
.BR ptrace (2).
|
|
.TP
|
|
.IR /proc/sys/kernel/zero\-paged " (PowerPC only)"
|
|
This file
|
|
contains a flag.
|
|
When enabled (nonzero), Linux-PPC will pre-zero pages in
|
|
the idle loop, possibly speeding up get_free_pages.
|
|
.TP
|
|
.I /proc/sys/net
|
|
This directory contains networking stuff.
|
|
Explanations for some of the files under this directory can be found in
|
|
.BR tcp (7)
|
|
and
|
|
.BR ip (7).
|
|
.TP
|
|
.I /proc/sys/net/core/bpf_jit_enable
|
|
See
|
|
.BR bpf (2).
|
|
.TP
|
|
.I /proc/sys/net/core/somaxconn
|
|
This file defines a ceiling value for the
|
|
.I backlog
|
|
argument of
|
|
.BR listen (2);
|
|
see the
|
|
.BR listen (2)
|
|
manual page for details.
|
|
.TP
|
|
.I /proc/sys/proc
|
|
This directory may be empty.
|
|
.TP
|
|
.I /proc/sys/sunrpc
|
|
This directory supports Sun remote procedure call for network filesystem
|
|
(NFS).
|
|
On some systems, it is not present.
|
|
.TP
|
|
.IR /proc/sys/user " (since Linux 4.9)"
|
|
See
|
|
.BR namespaces (7).
|
|
.TP
|
|
.I /proc/sys/vm
|
|
This directory contains files for memory management tuning, buffer, and
|
|
cache management.
|
|
.TP
|
|
.IR /proc/sys/vm/admin_reserve_kbytes " (since Linux 3.10)"
|
|
.\" commit 4eeab4f5580d11bffedc697684b91b0bca0d5009
|
|
This file defines the amount of free memory (in KiB) on the system that
|
|
should be reserved for users with the capability
|
|
.BR CAP_SYS_ADMIN .
|
|
.IP
|
|
The default value in this file is the minimum of [3% of free pages, 8MiB]
|
|
expressed as KiB.
|
|
The default is intended to provide enough for the superuser
|
|
to log in and kill a process, if necessary,
|
|
under the default overcommit 'guess' mode (i.e., 0 in
|
|
.IR /proc/sys/vm/overcommit_memory ).
|
|
.IP
|
|
Systems running in "overcommit never" mode (i.e., 2 in
|
|
.IR /proc/sys/vm/overcommit_memory )
|
|
should increase the value in this file to account
|
|
for the full virtual memory size of the programs used to recover (e.g.,
|
|
.BR login (1)
|
|
.BR ssh (1),
|
|
and
|
|
.BR top (1))
|
|
Otherwise, the superuser may not be able to log in to recover the system.
|
|
For example, on x86-64 a suitable value is 131072 (128MiB reserved).
|
|
.IP
|
|
Changing the value in this file takes effect whenever
|
|
an application requests memory.
|
|
.TP
|
|
.IR /proc/sys/vm/compact_memory " (since Linux 2.6.35)"
|
|
When 1 is written to this file, all zones are compacted such that free
|
|
memory is available in contiguous blocks where possible.
|
|
The effect of this action can be seen by examining
|
|
.IR /proc/buddyinfo .
|
|
.IP
|
|
Present only if the kernel was configured with
|
|
.BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR /proc/sys/vm/drop_caches " (since Linux 2.6.16)"
|
|
Writing to this file causes the kernel to drop clean caches, dentries, and
|
|
inodes from memory, causing that memory to become free.
|
|
This can be useful for memory management testing and
|
|
performing reproducible filesystem benchmarks.
|
|
Because writing to this file causes the benefits of caching to be lost,
|
|
it can degrade overall system performance.
|
|
.IP
|
|
To free pagecache, use:
|
|
.IP
|
|
echo 1 > /proc/sys/vm/drop_caches
|
|
.IP
|
|
To free dentries and inodes, use:
|
|
.IP
|
|
echo 2 > /proc/sys/vm/drop_caches
|
|
.IP
|
|
To free pagecache, dentries, and inodes, use:
|
|
.IP
|
|
echo 3 > /proc/sys/vm/drop_caches
|
|
.IP
|
|
Because writing to this file is a nondestructive operation and dirty objects
|
|
are not freeable, the
|
|
user should run
|
|
.BR sync (1)
|
|
first.
|
|
.TP
|
|
.IR /proc/sys/vm/sysctl_hugetlb_shm_group " (since Linux 2.6.7)"
|
|
This writable file contains a group ID that is allowed
|
|
to allocate memory using huge pages.
|
|
If a process has a filesystem group ID or any supplementary group ID that
|
|
matches this group ID,
|
|
then it can make huge-page allocations without holding the
|
|
.BR CAP_IPC_LOCK
|
|
capability; see
|
|
.BR memfd_create (2),
|
|
.BR mmap (2),
|
|
and
|
|
.BR shmget (2).
|
|
.TP
|
|
.IR /proc/sys/vm/legacy_va_layout " (since Linux 2.6.9)"
|
|
.\" The following is from Documentation/filesystems/proc.txt
|
|
If nonzero, this disables the new 32-bit memory-mapping layout;
|
|
the kernel will use the legacy (2.4) layout for all processes.
|
|
.TP
|
|
.IR /proc/sys/vm/memory_failure_early_kill " (since Linux 2.6.32)"
|
|
.\" The following is based on the text in Documentation/sysctl/vm.txt
|
|
Control how to kill processes when an uncorrected memory error
|
|
(typically a 2-bit error in a memory module)
|
|
that cannot be handled by the kernel
|
|
is detected in the background by hardware.
|
|
In some cases (like the page still having a valid copy on disk),
|
|
the kernel will handle the failure
|
|
transparently without affecting any applications.
|
|
But if there is no other up-to-date copy of the data,
|
|
it will kill processes to prevent any data corruptions from propagating.
|
|
.IP
|
|
The file has one of the following values:
|
|
.RS
|
|
.IP 1: 4
|
|
Kill all processes that have the corrupted-and-not-reloadable page mapped
|
|
as soon as the corruption is detected.
|
|
Note that this is not supported for a few types of pages,
|
|
such as kernel internally
|
|
allocated data or the swap cache, but works for the majority of user pages.
|
|
.IP 0: 4
|
|
Unmap the corrupted page from all processes and kill a process
|
|
only if it tries to access the page.
|
|
.RE
|
|
.IP
|
|
The kill is performed using a
|
|
.B SIGBUS
|
|
signal with
|
|
.I si_code
|
|
set to
|
|
.BR BUS_MCEERR_AO .
|
|
Processes can handle this if they want to; see
|
|
.BR sigaction (2)
|
|
for more details.
|
|
.IP
|
|
This feature is active only on architectures/platforms with advanced machine
|
|
check handling and depends on the hardware capabilities.
|
|
.IP
|
|
Applications can override the
|
|
.I memory_failure_early_kill
|
|
setting individually with the
|
|
.BR prctl (2)
|
|
.B PR_MCE_KILL
|
|
operation.
|
|
.IP
|
|
Present only if the kernel was configured with
|
|
.BR CONFIG_MEMORY_FAILURE .
|
|
.TP
|
|
.IR /proc/sys/vm/memory_failure_recovery " (since Linux 2.6.32)"
|
|
.\" The following is based on the text in Documentation/sysctl/vm.txt
|
|
Enable memory failure recovery (when supported by the platform).
|
|
.RS
|
|
.IP 1: 4
|
|
Attempt recovery.
|
|
.IP 0: 4
|
|
Always panic on a memory failure.
|
|
.RE
|
|
.IP
|
|
Present only if the kernel was configured with
|
|
.BR CONFIG_MEMORY_FAILURE .
|
|
.TP
|
|
.IR /proc/sys/vm/oom_dump_tasks " (since Linux 2.6.25)"
|
|
.\" The following is from Documentation/sysctl/vm.txt
|
|
Enables a system-wide task dump (excluding kernel threads) to be
|
|
produced when the kernel performs an OOM-killing.
|
|
The dump includes the following information
|
|
for each task (thread, process):
|
|
thread ID, real user ID, thread group ID (process ID),
|
|
virtual memory size, resident set size,
|
|
the CPU that the task is scheduled on,
|
|
oom_adj score (see the description of
|
|
.IR /proc/[pid]/oom_adj ),
|
|
and command name.
|
|
This is helpful to determine why the OOM-killer was invoked
|
|
and to identify the rogue task that caused it.
|
|
.IP
|
|
If this contains the value zero, this information is suppressed.
|
|
On very large systems with thousands of tasks,
|
|
it may not be feasible to dump the memory state information for each one.
|
|
Such systems should not be forced to incur a performance penalty in
|
|
OOM situations when the information may not be desired.
|
|
.IP
|
|
If this is set to nonzero, this information is shown whenever the
|
|
OOM-killer actually kills a memory-hogging task.
|
|
.IP
|
|
The default value is 0.
|
|
.TP
|
|
.IR /proc/sys/vm/oom_kill_allocating_task " (since Linux 2.6.24)"
|
|
.\" The following is from Documentation/sysctl/vm.txt
|
|
This enables or disables killing the OOM-triggering task in
|
|
out-of-memory situations.
|
|
.IP
|
|
If this is set to zero, the OOM-killer will scan through the entire
|
|
tasklist and select a task based on heuristics to kill.
|
|
This normally selects a rogue memory-hogging task that
|
|
frees up a large amount of memory when killed.
|
|
.IP
|
|
If this is set to nonzero, the OOM-killer simply kills the task that
|
|
triggered the out-of-memory condition.
|
|
This avoids a possibly expensive tasklist scan.
|
|
.IP
|
|
If
|
|
.I /proc/sys/vm/panic_on_oom
|
|
is nonzero, it takes precedence over whatever value is used in
|
|
.IR /proc/sys/vm/oom_kill_allocating_task .
|
|
.IP
|
|
The default value is 0.
|
|
.TP
|
|
.IR /proc/sys/vm/overcommit_kbytes " (since Linux 3.14)"
|
|
.\" commit 49f0ce5f92321cdcf741e35f385669a421013cb7
|
|
This writable file provides an alternative to
|
|
.IR /proc/sys/vm/overcommit_ratio
|
|
for controlling the
|
|
.I CommitLimit
|
|
when
|
|
.IR /proc/sys/vm/overcommit_memory
|
|
has the value 2.
|
|
It allows the amount of memory overcommitting to be specified as
|
|
an absolute value (in kB),
|
|
rather than as a percentage, as is done with
|
|
.IR overcommit_ratio .
|
|
This allows for finer-grained control of
|
|
.IR CommitLimit
|
|
on systems with extremely large memory sizes.
|
|
.IP
|
|
Only one of
|
|
.IR overcommit_kbytes
|
|
or
|
|
.IR overcommit_ratio
|
|
can have an effect:
|
|
if
|
|
.IR overcommit_kbytes
|
|
has a nonzero value, then it is used to calculate
|
|
.IR CommitLimit ,
|
|
otherwise
|
|
.IR overcommit_ratio
|
|
is used.
|
|
Writing a value to either of these files causes the
|
|
value in the other file to be set to zero.
|
|
.TP
|
|
.I /proc/sys/vm/overcommit_memory
|
|
This file contains the kernel virtual memory accounting mode.
|
|
Values are:
|
|
.RS
|
|
.IP
|
|
0: heuristic overcommit (this is the default)
|
|
.br
|
|
1: always overcommit, never check
|
|
.br
|
|
2: always check, never overcommit
|
|
.RE
|
|
.IP
|
|
In mode 0, calls of
|
|
.BR mmap (2)
|
|
with
|
|
.B MAP_NORESERVE
|
|
are not checked, and the default check is very weak,
|
|
leading to the risk of getting a process "OOM-killed".
|
|
.IP
|
|
In mode 1, the kernel pretends there is always enough memory,
|
|
until memory actually runs out.
|
|
One use case for this mode is scientific computing applications
|
|
that employ large sparse arrays.
|
|
In Linux kernel versions before 2.6.0, any nonzero value implies mode 1.
|
|
.IP
|
|
In mode 2 (available since Linux 2.6), the total virtual address space
|
|
that can be allocated
|
|
.RI ( CommitLimit
|
|
in
|
|
.IR /proc/meminfo )
|
|
is calculated as
|
|
.IP
|
|
CommitLimit = (total_RAM \- total_huge_TLB) *
|
|
overcommit_ratio / 100 + total_swap
|
|
.IP
|
|
where:
|
|
.RS 12
|
|
.IP * 3
|
|
.I total_RAM
|
|
is the total amount of RAM on the system;
|
|
.IP *
|
|
.I total_huge_TLB
|
|
is the amount of memory set aside for huge pages;
|
|
.IP *
|
|
.I overcommit_ratio
|
|
is the value in
|
|
.IR /proc/sys/vm/overcommit_ratio ;
|
|
and
|
|
.IP *
|
|
.I total_swap
|
|
is the amount of swap space.
|
|
.RE
|
|
.IP
|
|
For example, on a system with 16 GB of physical RAM, 16 GB
|
|
of swap, no space dedicated to huge pages, and an
|
|
.I overcommit_ratio
|
|
of 50, this formula yields a
|
|
.I CommitLimit
|
|
of 24 GB.
|
|
.IP
|
|
Since Linux 3.14, if the value in
|
|
.I /proc/sys/vm/overcommit_kbytes
|
|
is nonzero, then
|
|
.I CommitLimit
|
|
is instead calculated as:
|
|
.IP
|
|
CommitLimit = overcommit_kbytes + total_swap
|
|
.IP
|
|
See also the description of
|
|
.IR /proc/sys/vm/admin_reserve_kbytes
|
|
and
|
|
.IR /proc/sys/vm/user_reserve_kbytes .
|
|
.TP
|
|
.IR /proc/sys/vm/overcommit_ratio " (since Linux 2.6.0)"
|
|
This writable file defines a percentage by which memory
|
|
can be overcommitted.
|
|
The default value in the file is 50.
|
|
See the description of
|
|
.IR /proc/sys/vm/overcommit_memory .
|
|
.TP
|
|
.IR /proc/sys/vm/panic_on_oom " (since Linux 2.6.18)"
|
|
.\" The following is adapted from Documentation/sysctl/vm.txt
|
|
This enables or disables a kernel panic in
|
|
an out-of-memory situation.
|
|
.IP
|
|
If this file is set to the value 0,
|
|
the kernel's OOM-killer will kill some rogue process.
|
|
Usually, the OOM-killer is able to kill a rogue process and the
|
|
system will survive.
|
|
.IP
|
|
If this file is set to the value 1,
|
|
then the kernel normally panics when out-of-memory happens.
|
|
However, if a process limits allocations to certain nodes
|
|
using memory policies
|
|
.RB ( mbind (2)
|
|
.BR MPOL_BIND )
|
|
or cpusets
|
|
.RB ( cpuset (7))
|
|
and those nodes reach memory exhaustion status,
|
|
one process may be killed by the OOM-killer.
|
|
No panic occurs in this case:
|
|
because other nodes' memory may be free,
|
|
this means the system as a whole may not have reached
|
|
an out-of-memory situation yet.
|
|
.IP
|
|
If this file is set to the value 2,
|
|
the kernel always panics when an out-of-memory condition occurs.
|
|
.IP
|
|
The default value is 0.
|
|
1 and 2 are for failover of clustering.
|
|
Select either according to your policy of failover.
|
|
.TP
|
|
.IR /proc/sys/vm/swappiness
|
|
.\" The following is from Documentation/sysctl/vm.txt
|
|
The value in this file controls how aggressively the kernel will swap
|
|
memory pages.
|
|
Higher values increase aggressiveness, lower values
|
|
decrease aggressiveness.
|
|
The default value is 60.
|
|
.TP
|
|
.IR /proc/sys/vm/user_reserve_kbytes " (since Linux 3.10)"
|
|
.\" commit c9b1d0981fcce3d9976d7b7a56e4e0503bc610dd
|
|
Specifies an amount of memory (in KiB) to reserve for user processes.
|
|
This is intended to prevent a user from starting a single memory hogging
|
|
process, such that they cannot recover (kill the hog).
|
|
The value in this file has an effect only when
|
|
.IR /proc/sys/vm/overcommit_memory
|
|
is set to 2 ("overcommit never" mode).
|
|
In this case, the system reserves an amount of memory that is the minimum
|
|
of [3% of current process size,
|
|
.IR user_reserve_kbytes ].
|
|
.IP
|
|
The default value in this file is the minimum of [3% of free pages, 128MiB]
|
|
expressed as KiB.
|
|
.IP
|
|
If the value in this file is set to zero,
|
|
then a user will be allowed to allocate all free memory with a single process
|
|
(minus the amount reserved by
|
|
.IR /proc/sys/vm/admin_reserve_kbytes ).
|
|
Any subsequent attempts to execute a command will result in
|
|
"fork: Cannot allocate memory".
|
|
.IP
|
|
Changing the value in this file takes effect whenever
|
|
an application requests memory.
|
|
.TP
|
|
.IR /proc/sys/vm/unprivileged_userfaultfd " (since Linux 5.2)"
|
|
.\" cefdca0a86be517bc390fc4541e3674b8e7803b0
|
|
This (writable) file exposes a flag that controls whether
|
|
unprivileged processes are allowed to employ
|
|
.BR userfaultfd (2).
|
|
If this file has the value 1, then unprivileged processes may use
|
|
.BR userfaultfd (2).
|
|
If this file has the value 0, then only processes that have the
|
|
.B CAP_SYS_PTRACE
|
|
capability may employ
|
|
.BR userfaultfd (2).
|
|
The default value in this file is 1.
|
|
.TP
|
|
.IR /proc/sysrq\-trigger " (since Linux 2.4.21)"
|
|
Writing a character to this file triggers the same SysRq function as
|
|
typing ALT-SysRq-<character> (see the description of
|
|
.IR /proc/sys/kernel/sysrq ).
|
|
This file is normally writable only by
|
|
.IR root .
|
|
For further details see the Linux kernel source file
|
|
.I Documentation/admin\-guide/sysrq.rst
|
|
.\" commit 9d85025b0418163fae079c9ba8f8445212de8568
|
|
(or
|
|
.I Documentation/sysrq.txt
|
|
before Linux 4.10).
|
|
.TP
|
|
.I /proc/sysvipc
|
|
Subdirectory containing the pseudo-files
|
|
.IR msg ", " sem " and " shm "."
|
|
These files list the System V Interprocess Communication (IPC) objects
|
|
(respectively: message queues, semaphores, and shared memory)
|
|
that currently exist on the system,
|
|
providing similar information to that available via
|
|
.BR ipcs (1).
|
|
These files have headers and are formatted (one IPC object per line)
|
|
for easy understanding.
|
|
.BR sysvipc (7)
|
|
provides further background on the information shown by these files.
|
|
.TP
|
|
.IR /proc/thread\-self " (since Linux 3.17)"
|
|
.\" commit 0097875bd41528922fb3bb5f348c53f17e00e2fd
|
|
This directory refers to the thread accessing the
|
|
.I /proc
|
|
filesystem,
|
|
and is identical to the
|
|
.I /proc/self/task/[tid]
|
|
directory named by the process thread ID
|
|
.RI ( [tid] )
|
|
of the same thread.
|
|
.TP
|
|
.IR /proc/timer_list " (since Linux 2.6.21)"
|
|
.\" commit 289f480af87e45f7a6de6ba9b4c061c2e259fe98
|
|
This read-only file exposes a list of all currently pending
|
|
(high-resolution) timers,
|
|
all clock-event sources, and their parameters in a human-readable form.
|
|
.TP
|
|
.IR /proc/timer_stats " (from Linux 2.6.21 until Linux 4.10)"
|
|
.\" commit 82f67cd9fca8c8762c15ba7ed0d5747588c1e221
|
|
.\" Date: Fri Feb 16 01:28:13 2007 -0800
|
|
.\" Text largely derived from Documentation/timers/timer_stats.txt
|
|
.\" removed in commit dfb4357da6ddbdf57d583ba64361c9d792b0e0b1
|
|
.\" Date: Wed Feb 8 11:26:59 2017 -0800
|
|
This is a debugging facility to make timer (ab)use in a Linux
|
|
system visible to kernel and user-space developers.
|
|
It can be used by kernel and user-space developers to verify that
|
|
their code does not make undue use of timers.
|
|
The goal is to avoid unnecessary wakeups,
|
|
thereby optimizing power consumption.
|
|
.IP
|
|
If enabled in the kernel
|
|
.RB ( CONFIG_TIMER_STATS ),
|
|
but not used,
|
|
it has almost zero run-time overhead and a relatively small
|
|
data-structure overhead.
|
|
Even if collection is enabled at run time, overhead is low:
|
|
all the locking is per-CPU and lookup is hashed.
|
|
.IP
|
|
The
|
|
.I /proc/timer_stats
|
|
file is used both to control sampling facility and to read out the
|
|
sampled information.
|
|
.IP
|
|
The
|
|
.I timer_stats
|
|
functionality is inactive on bootup.
|
|
A sampling period can be started using the following command:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
# echo 1 > /proc/timer_stats
|
|
.EE
|
|
.in
|
|
.IP
|
|
The following command stops a sampling period:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
# echo 0 > /proc/timer_stats
|
|
.EE
|
|
.in
|
|
.IP
|
|
The statistics can be retrieved by:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
$ cat /proc/timer_stats
|
|
.EE
|
|
.in
|
|
.IP
|
|
While sampling is enabled, each readout from
|
|
.I /proc/timer_stats
|
|
will see
|
|
newly updated statistics.
|
|
Once sampling is disabled, the sampled information
|
|
is kept until a new sample period is started.
|
|
This allows multiple readouts.
|
|
.IP
|
|
Sample output from
|
|
.IR /proc/timer_stats :
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
.RB $ " cat /proc/timer_stats"
|
|
Timer Stats Version: v0.3
|
|
Sample period: 1.764 s
|
|
Collection: active
|
|
255, 0 swapper/3 hrtimer_start_range_ns (tick_sched_timer)
|
|
71, 0 swapper/1 hrtimer_start_range_ns (tick_sched_timer)
|
|
58, 0 swapper/0 hrtimer_start_range_ns (tick_sched_timer)
|
|
4, 1694 gnome\-shell mod_delayed_work_on (delayed_work_timer_fn)
|
|
17, 7 rcu_sched rcu_gp_kthread (process_timeout)
|
|
\&...
|
|
1, 4911 kworker/u16:0 mod_delayed_work_on (delayed_work_timer_fn)
|
|
1D, 2522 kworker/0:0 queue_delayed_work_on (delayed_work_timer_fn)
|
|
1029 total events, 583.333 events/sec
|
|
.EE
|
|
.in
|
|
.IP
|
|
The output columns are:
|
|
.RS
|
|
.IP * 3
|
|
a count of the number of events,
|
|
optionally (since Linux 2.6.23) followed by the letter \(aqD\(aq
|
|
.\" commit c5c061b8f9726bc2c25e19dec227933a13d1e6b7 deferrable timers
|
|
if this is a deferrable timer;
|
|
.IP *
|
|
the PID of the process that initialized the timer;
|
|
.IP *
|
|
the name of the process that initialized the timer;
|
|
.IP *
|
|
the function where the timer was initialized; and
|
|
.IP *
|
|
(in parentheses)
|
|
the callback function that is associated with the timer.
|
|
.RE
|
|
.IP
|
|
During the Linux 4.11 development cycle,
|
|
this file was removed because of security concerns,
|
|
as it exposes information across namespaces.
|
|
Furthermore, it is possible to obtain
|
|
the same information via in-kernel tracing facilities such as ftrace.
|
|
.TP
|
|
.I /proc/tty
|
|
Subdirectory containing the pseudo-files and subdirectories for
|
|
tty drivers and line disciplines.
|
|
.TP
|
|
.I /proc/uptime
|
|
This file contains two numbers (values in seconds): the uptime of the
|
|
system (including time spent in suspend) and the amount of time spent
|
|
in the idle process.
|
|
.TP
|
|
.I /proc/version
|
|
This string identifies the kernel version that is currently running.
|
|
It includes the contents of
|
|
.IR /proc/sys/kernel/ostype ,
|
|
.IR /proc/sys/kernel/osrelease ,
|
|
and
|
|
.IR /proc/sys/kernel/version .
|
|
For example:
|
|
.IP
|
|
.in +4n
|
|
.EX
|
|
Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994
|
|
.EE
|
|
.in
|
|
.\" FIXME 2.6.13 seems to have /proc/vmcore implemented; document this
|
|
.\" See Documentation/kdump/kdump.txt
|
|
.\" commit 666bfddbe8b8fd4fd44617d6c55193d5ac7edb29
|
|
.\" Needs CONFIG_VMCORE
|
|
.\"
|
|
.TP
|
|
.IR /proc/vmstat " (since Linux 2.6.0)"
|
|
This file displays various virtual memory statistics.
|
|
Each line of this file contains a single name-value pair,
|
|
delimited by white space.
|
|
Some lines are present only if the kernel was configured with
|
|
suitable options.
|
|
(In some cases, the options required for particular files have changed
|
|
across kernel versions, so they are not listed here.
|
|
Details can be found by consulting the kernel source code.)
|
|
The following fields may be present:
|
|
.\" FIXME We need explanations for each of the following fields...
|
|
.RS
|
|
.TP
|
|
.IR nr_free_pages " (since Linux 2.6.31)"
|
|
.\" commit d23ad42324cc4378132e51f2fc5c9ba6cbe75182
|
|
.TP
|
|
.IR nr_alloc_batch " (since Linux 3.12)"
|
|
.\" commit 81c0a2bb515fd4daae8cab64352877480792b515
|
|
.TP
|
|
.IR nr_inactive_anon " (since Linux 2.6.28)"
|
|
.\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db
|
|
.TP
|
|
.IR nr_active_anon " (since Linux 2.6.28)"
|
|
.\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db
|
|
.TP
|
|
.IR nr_inactive_file " (since Linux 2.6.28)"
|
|
.\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db
|
|
.TP
|
|
.IR nr_active_file " (since Linux 2.6.28)"
|
|
.\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db
|
|
.TP
|
|
.IR nr_unevictable " (since Linux 2.6.28)"
|
|
.\" commit 7b854121eb3e5ba0241882ff939e2c485228c9c5
|
|
.TP
|
|
.IR nr_mlock " (since Linux 2.6.28)"
|
|
.\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820
|
|
.TP
|
|
.IR nr_anon_pages " (since Linux 2.6.18)"
|
|
.\" commit f3dbd34460ff54962d3e3244b6bcb7f5295356e6
|
|
.TP
|
|
.IR nr_mapped " (since Linux 2.6.0)"
|
|
.TP
|
|
.IR nr_file_pages " (since Linux 2.6.18)"
|
|
.\" commit 347ce434d57da80fd5809c0c836f206a50999c26
|
|
.TP
|
|
.IR nr_dirty " (since Linux 2.6.0)"
|
|
.TP
|
|
.IR nr_writeback " (since Linux 2.6.0)"
|
|
.TP
|
|
.IR nr_slab_reclaimable " (since Linux 2.6.19)"
|
|
.\" commit 972d1a7b140569084439a81265a0f15b74e924e0
|
|
.\" Linux 2.6.0 had nr_slab
|
|
.TP
|
|
.IR nr_slab_unreclaimable " (since Linux 2.6.19)"
|
|
.\" commit 972d1a7b140569084439a81265a0f15b74e924e0
|
|
.TP
|
|
.IR nr_page_table_pages " (since Linux 2.6.0)"
|
|
.TP
|
|
.IR nr_kernel_stack " (since Linux 2.6.32)"
|
|
.\" commit c6a7f5728a1db45d30df55a01adc130b4ab0327c
|
|
Amount of memory allocated to kernel stacks.
|
|
.TP
|
|
.IR nr_unstable " (since Linux 2.6.0)"
|
|
.TP
|
|
.IR nr_bounce " (since Linux 2.6.12)"
|
|
.\" commit edfbe2b0038723e5699ab22695ccd62b5542a5c1
|
|
.TP
|
|
.IR nr_vmscan_write " (since Linux 2.6.19)"
|
|
.\" commit e129b5c23c2b471d47f1c5d2b8b193fc2034af43
|
|
.TP
|
|
.IR nr_vmscan_immediate_reclaim " (since Linux 3.2)"
|
|
.\" commit 49ea7eb65e7c5060807fb9312b1ad4c3eab82e2c
|
|
.TP
|
|
.IR nr_writeback_temp " (since Linux 2.6.26)"
|
|
.\" commit fc3ba692a4d19019387c5acaea63131f9eab05dd
|
|
.TP
|
|
.IR nr_isolated_anon " (since Linux 2.6.32)"
|
|
.\" commit a731286de62294b63d8ceb3c5914ac52cc17e690
|
|
.TP
|
|
.IR nr_isolated_file " (since Linux 2.6.32)"
|
|
.\" commit a731286de62294b63d8ceb3c5914ac52cc17e690
|
|
.TP
|
|
.IR nr_shmem " (since Linux 2.6.32)"
|
|
.\" commit 4b02108ac1b3354a22b0d83c684797692efdc395
|
|
Pages used by shmem and
|
|
.BR tmpfs (5).
|
|
.TP
|
|
.IR nr_dirtied " (since Linux 2.6.37)"
|
|
.\" commit ea941f0e2a8c02ae876cd73deb4e1557248f258c
|
|
.TP
|
|
.IR nr_written " (since Linux 2.6.37)"
|
|
.\" commit ea941f0e2a8c02ae876cd73deb4e1557248f258c
|
|
.TP
|
|
.IR nr_pages_scanned " (since Linux 3.17)"
|
|
.\" commit 0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd
|
|
.TP
|
|
.IR numa_hit " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR numa_miss " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR numa_foreign " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR numa_interleave " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR numa_local " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR numa_other " (since Linux 2.6.18)"
|
|
.\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR workingset_refault " (since Linux 3.15)"
|
|
.\" commit a528910e12ec7ee203095eb1711468a66b9b60b0
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR workingset_activate " (since Linux 3.15)"
|
|
.\" commit a528910e12ec7ee203095eb1711468a66b9b60b0
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR workingset_nodereclaim " (since Linux 3.15)"
|
|
.\" commit 449dd6984d0e47643c04c807f609dd56d48d5bcc
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR nr_anon_transparent_hugepages " (since Linux 2.6.38)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR nr_free_cma " (since Linux 3.7)"
|
|
.\" commit d1ce749a0db12202b711d1aba1d29e823034648d
|
|
Number of free CMA (Contiguous Memory Allocator) pages.
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR nr_dirty_threshold " (since Linux 2.6.37)"
|
|
.\" commit 79da826aee6a10902ef411bc65864bd02102fa83
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR nr_dirty_background_threshold " (since Linux 2.6.37)"
|
|
.\" commit 79da826aee6a10902ef411bc65864bd02102fa83
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgpgin " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgpgout " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pswpin " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pswpout " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgalloc_dma " (since Linux 2.6.5)"
|
|
.\" Linux 2.6.0 had pgalloc
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgalloc_dma32 " (since Linux 2.6.16)"
|
|
.\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgalloc_normal " (since Linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgalloc_high " (since Linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgalloc_movable " (since Linux 2.6.23)"
|
|
.\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgfree " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgactivate " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgdeactivate " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgfault " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgmajfault " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgrefill_dma " (since Linux 2.6.5)"
|
|
.\" Linux 2.6.0 had pgrefill
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgrefill_dma32 " (since Linux 2.6.16)"
|
|
.\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgrefill_normal " (since Linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgrefill_high " (since Linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgrefill_movable " (since Linux 2.6.23)"
|
|
.\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.\" Formerly there were
|
|
.\" pgsteal_high
|
|
.\" pgsteal_normal
|
|
.\" pgsteal_dma32
|
|
.\" pgsteal_dma
|
|
.\" These were split out into pgsteal_kswapd* and pgsteal_direct*
|
|
.\" in commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.TP
|
|
.IR pgsteal_kswapd_dma " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Linux 2.6.0 had pgsteal
|
|
.\" Present only if the kernel was configured with
|
|
.\" .\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_kswapd_dma32 " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_kswapd_normal " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_kswapd_high " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgsteal_kswapd_movable " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_direct_dma
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_direct_dma32 " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_direct_normal " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgsteal_direct_high " (since Linux 3.4)"
|
|
.\" commit 904249aa68010c8e223263c922fcbb840a3f42e4
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgsteal_direct_movable " (since Linux 2.6.23)"
|
|
.\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_kswapd_dma
|
|
.\" Linux 2.6.0 had pgscan
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_kswapd_dma32 " (since Linux 2.6.16)"
|
|
.\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_kswapd_normal " (since Linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_kswapd_high
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgscan_kswapd_movable " (since Linux 2.6.23)"
|
|
.\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_direct_dma
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_direct_dma32 " (since Linux 2.6.16)"
|
|
.\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_direct_normal
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_direct_high
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HIGHMEM .
|
|
.TP
|
|
.IR pgscan_direct_movable " (since Linux 2.6.23)"
|
|
.\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgscan_direct_throttle " (since Linux 3.6)"
|
|
.\" commit 68243e76ee343d63c6cf76978588a885951e2818
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR zone_reclaim_failed " (since linux 2.6.31)"
|
|
.\" commit 24cf72518c79cdcda486ed26074ff8151291cf65
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA .
|
|
.TP
|
|
.IR pginodesteal " (since linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR slabs_scanned " (since linux 2.6.5)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR kswapd_inodesteal " (since linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR kswapd_low_wmark_hit_quickly " (since 2.6.33)"
|
|
.\" commit bb3ab596832b920c703d1aea1ce76d69c0f71fb7
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR kswapd_high_wmark_hit_quickly " (since 2.6.33)"
|
|
.\" commit bb3ab596832b920c703d1aea1ce76d69c0f71fb7
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pageoutrun " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR allocstall " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR pgrotated " (since Linux 2.6.0)"
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR drop_pagecache " (since Linux 3.15)"
|
|
.\" commit 5509a5d27b971a90b940e148ca9ca53312e4fa7a
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR drop_slab " (since Linux 3.15)"
|
|
.\" commit 5509a5d27b971a90b940e148ca9ca53312e4fa7a
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR numa_pte_updates " (since Linux 3.8)"
|
|
.\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING .
|
|
.TP
|
|
.IR numa_huge_pte_updates " (since Linux 3.13)"
|
|
.\" commit 72403b4a0fbdf433c1fe0127e49864658f6f6468
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING .
|
|
.TP
|
|
.IR numa_hint_faults " (since Linux 3.8)"
|
|
.\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING .
|
|
.TP
|
|
.IR numa_hint_faults_local " (since Linux 3.8)"
|
|
.\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING .
|
|
.TP
|
|
.IR numa_pages_migrated " (since Linux 3.8)"
|
|
.\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING
|
|
.\" and
|
|
.\" .BR CONFIG_NUMA_BALANCING .
|
|
.TP
|
|
.IR pgmigrate_success " (since Linux 3.8)"
|
|
.\" commit 5647bc293ab15f66a7b1cda850c5e9d162a6c7c2
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_MIGRATION .
|
|
.TP
|
|
.IR pgmigrate_fail " (since Linux 3.8)"
|
|
.\" commit 5647bc293ab15f66a7b1cda850c5e9d162a6c7c2
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_MIGRATION .
|
|
.TP
|
|
.IR compact_migrate_scanned " (since Linux 3.8)"
|
|
.\" commit 397487db696cae0b026a474a5cd66f4e372995e6
|
|
.\" Linux 3.8 dropped compact_blocks_moved, compact_pages_moved, and
|
|
.\" compact_pagemigrate_failed
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR compact_free_scanned " (since Linux 3.8)"
|
|
.\" commit 397487db696cae0b026a474a5cd66f4e372995e6
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR compact_isolated " (since Linux 3.8)"
|
|
.\" commit 397487db696cae0b026a474a5cd66f4e372995e6
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR compact_stall " (since Linux 2.6.35)"
|
|
.\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR compact_fail " (since Linux 2.6.35)"
|
|
.\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR compact_success " (since Linux 2.6.35)"
|
|
.\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_COMPACTION .
|
|
.TP
|
|
.IR htlb_buddy_alloc_success " (since Linux 2.6.26)"
|
|
.\" commit 3b1163006332302117b1b2acf226d4014ff46525
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HUGETLB_PAGE .
|
|
.TP
|
|
.IR htlb_buddy_alloc_fail " (since Linux 2.6.26)"
|
|
.\" commit 3b1163006332302117b1b2acf226d4014ff46525
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_HUGETLB_PAGE .
|
|
.TP
|
|
.IR unevictable_pgs_culled " (since Linux 2.6.28)"
|
|
.\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_scanned " (since Linux 2.6.28)"
|
|
.\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_rescued " (since Linux 2.6.28)"
|
|
.\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_mlocked " (since Linux 2.6.28)"
|
|
.\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_munlocked " (since Linux 2.6.28)"
|
|
.\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_cleared " (since Linux 2.6.28)"
|
|
.\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.TP
|
|
.IR unevictable_pgs_stranded " (since Linux 2.6.28)"
|
|
.\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS .
|
|
.\" Linux 3.7 removed unevictable_pgs_mlockfreed
|
|
.TP
|
|
.IR thp_fault_alloc " (since Linux 2.6.39)"
|
|
.\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_fault_fallback " (since Linux 2.6.39)"
|
|
.\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_collapse_alloc " (since Linux 2.6.39)"
|
|
.\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_collapse_alloc_failed " (since Linux 2.6.39)"
|
|
.\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_split " (since Linux 2.6.39)"
|
|
.\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_zero_page_alloc " (since Linux 3.8)"
|
|
.\" commit d8a8e1f0da3d29d7268b3300c96a059d63901b76
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR thp_zero_page_alloc_failed " (since Linux 3.8)"
|
|
.\" commit d8a8e1f0da3d29d7268b3300c96a059d63901b76
|
|
See the kernel source file
|
|
.IR Documentation/admin\-guide/mm/transhuge.rst .
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_TRANSPARENT_HUGEPAGE .
|
|
.TP
|
|
.IR balloon_inflate " (since Linux 3.18)"
|
|
.\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_MEMORY_BALLOON .
|
|
.TP
|
|
.IR balloon_deflate " (since Linux 3.18)"
|
|
.\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS
|
|
.\" and
|
|
.\" .BR CONFIG_MEMORY_BALLOON .
|
|
.TP
|
|
.IR balloon_migrate " (since Linux 3.18)"
|
|
.\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_VM_EVENT_COUNTERS ,
|
|
.\" .BR CONFIG_MEMORY_BALLOON ,
|
|
.\" and
|
|
.\" .BR CONFIG_BALLOON_COMPACTION .
|
|
.TP
|
|
.IR nr_tlb_remote_flush " (since Linux 3.12)"
|
|
.\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_TLBFLUSH
|
|
.\" and
|
|
.\" .BR CONFIG_SMP .
|
|
.TP
|
|
.IR nr_tlb_remote_flush_received " (since Linux 3.12)"
|
|
.\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_TLBFLUSH
|
|
.\" and
|
|
.\" .BR CONFIG_SMP .
|
|
.TP
|
|
.IR nr_tlb_local_flush_all " (since Linux 3.12)"
|
|
.\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_TLBFLUSH .
|
|
.TP
|
|
.IR nr_tlb_local_flush_one " (since Linux 3.12)"
|
|
.\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_TLBFLUSH .
|
|
.TP
|
|
.IR vmacache_find_calls " (since Linux 3.16)"
|
|
.\" commit 4f115147ff802267d0aa41e361c5aa5bd933d896
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_VM_VMACACHE .
|
|
.TP
|
|
.IR vmacache_find_hits " (since Linux 3.16)"
|
|
.\" commit 4f115147ff802267d0aa41e361c5aa5bd933d896
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_VM_VMACACHE .
|
|
.TP
|
|
.IR vmacache_full_flushes " (since Linux 3.19)"
|
|
.\" commit f5f302e21257ebb0c074bbafc37606c26d28cc3d
|
|
.\" Present only if the kernel was configured with
|
|
.\" .BR CONFIG_DEBUG_VM_VMACACHE .
|
|
.RE
|
|
.TP
|
|
.IR /proc/zoneinfo " (since Linux 2.6.13)"
|
|
This file displays information about memory zones.
|
|
This is useful for analyzing virtual memory behavior.
|
|
.\" FIXME more should be said about /proc/zoneinfo
|
|
.SH NOTES
|
|
Many files contain strings (e.g., the environment and command line)
|
|
that are in the internal format,
|
|
with subfields terminated by null bytes (\(aq\e0\(aq).
|
|
When inspecting such files, you may find that the results are more readable
|
|
if you use a command of the following form to display them:
|
|
.PP
|
|
.in +4n
|
|
.EX
|
|
.RB "$" " cat \fIfile\fP | tr \(aq\e000\(aq \(aq\en\(aq"
|
|
.EE
|
|
.in
|
|
.PP
|
|
This manual page is incomplete, possibly inaccurate, and is the kind
|
|
of thing that needs to be updated very often.
|
|
.\" .SH ACKNOWLEDGEMENTS
|
|
.\" The material on /proc/sys/fs and /proc/sys/kernel is closely based on
|
|
.\" kernel source documentation files written by Rik van Riel.
|
|
.SH SEE ALSO
|
|
.BR cat (1),
|
|
.BR dmesg (1),
|
|
.BR find (1),
|
|
.BR free (1),
|
|
.BR htop (1),
|
|
.BR init (1),
|
|
.BR ps (1),
|
|
.BR pstree (1),
|
|
.BR tr (1),
|
|
.BR uptime (1),
|
|
.BR chroot (2),
|
|
.BR mmap (2),
|
|
.BR readlink (2),
|
|
.BR syslog (2),
|
|
.BR slabinfo (5),
|
|
.BR sysfs (5),
|
|
.BR hier (7),
|
|
.BR namespaces (7),
|
|
.BR time (7),
|
|
.BR arp (8),
|
|
.BR hdparm (8),
|
|
.BR ifconfig (8),
|
|
.BR lsmod (8),
|
|
.BR lspci (8),
|
|
.BR mount (8),
|
|
.BR netstat (8),
|
|
.BR procinfo (8),
|
|
.BR route (8),
|
|
.BR sysctl (8)
|
|
.PP
|
|
The Linux kernel source files:
|
|
.IR Documentation/filesystems/proc.rst ,
|
|
.IR Documentation/admin\-guide/sysctl/fs.rst ,
|
|
.IR Documentation/admin\-guide/sysctl/kernel.rst ,
|
|
.IR Documentation/admin\-guide/sysctl/net.rst ,
|
|
and
|
|
.IR Documentation/admin\-guide/sysctl/vm.rst .
|