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Document /proc/PID/oom_score, which was new in kernel 2.6.11. 

This file displays the "badness" score of the process, which
provides the basis for OOM-killer decisions.

Document /proc/PID/oom_adj, which was new in kernel 2.6.11.
This file influences the oom_score of a process.

Document /proc/PID/limits, which was new in 2.6.24.
This file displays a process's resource limits.

Document /proc/PID/fdinfo/*, which was new in 2.6.22.
These files display info about each descriptor opened by the
process: the current file offset, and the file access mode +
file status flags as set in open() or fcntl(F_SETFL).

Document /proc/PID/mountinfo, which was new in 2.6.26.
This file displays information about mount points.
Closely based on text from Documentation/filesystems/proc.txt.

Document /proc/PID/mountstats, which was new in 2.6.17.
This file displays statistics about mount points.
This commit is contained in:
Michael Kerrisk 2008-06-12 05:49:06 +00:00
parent a3a22b7fc3
commit b4e9ee8f48
1 changed files with 270 additions and 15 deletions
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285
man5/proc.5
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@ -1,4 +1,5 @@
.\" Copyright (C) 1994, 1995 by Daniel Quinlan (quinlan@yggdrasil.com)
.\" and Copyright (C) 2002-2008 Michael Kerrisk <mtk.manpages@gmail.com>
.\" with networking additions from Alan Cox (A.Cox@swansea.ac.uk)
.\" and scsi additions from Michael Neuffer (neuffer@mail.uni-mainz.de)
.\" and sysctl additions from Andries Brouwer (aeb@cwi.nl)
@ -39,8 +40,10 @@
.\" 2005-07-13, mtk, added /proc/sys/fs/mqueue/*
.\" 2005-09-16, mtk, Added /proc/sys/fs/suid_dumpable
.\" 2005-09-19, mtk, added /proc/zoneinfo
.\" 2005-03-01, mtk, moved /proc/sys/fs/mqueue/* material to
.\" mq_overview.7.
.\" 2005-03-01, mtk, moved /proc/sys/fs/mqueue/* material to mq_overview.7.
.\" 2008-05-05, mtk, Added /proc/PID/oom_score, /proc/PID/oom_adj,
.\" /proc/PID/limits, /proc/PID/mountinfo, /proc/PID/mounstats,
.\" and /proc/PID/fdinfo/*.
.\"
.\" FIXME 2.6.14 has /proc/PID/numa_maps (if CONFIG_NUMA is
.\" enabled); this needs to be documented.
@ -57,7 +60,7 @@
.\" to see what information could be imported from that file
.\" into this file.
.\"
.TH PROC 5 2007-11-30 "Linux" "Linux Programmer's Manual"
.TH PROC 5 2008-06-22 "Linux" "Linux Programmer's Manual"
.SH NAME
proc \- process information pseudo-file system
.SH DESCRIPTION
@ -78,6 +81,12 @@ There is a numerical subdirectory for each running process; the
subdirectory is named by the process ID.
Each such subdirectory contains the following
pseudo-files and directories.
.\" FIXME Describe /proc/[number]/attr and
.\" /proc/PID/task/TID/attr
.\" This is a directory
.\" Added in ???
.\" CONFIG_SECURITY
.\"
.TP
.IR /proc/[number]/auxv " (since 2.6.0-test7)"
This contains the contents of the ELF interpreter information passed
@ -85,6 +94,17 @@ 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.
.\" FIXME Describe /proc/[number]/cgroup and
.\" /proc/PID/task/TID/cgroup
.\" Info in Documentation/cgroups.txt
.\" Added in 2.6.24
.\" CONFIG_CGROUPS
.\"
.\" FIXME Describe /proc/[number]/clear_refs
.\" Added in 2.6.22
.\" "Clears page referenced bits shown in smaps output"
.\" write-only
.\" CONFIG_PROC_PAGE_MONITOR
.TP
.I /proc/[number]/cmdline
This holds the complete command line for the process,
@ -95,6 +115,14 @@ that is, a read on this file will return 0 characters.
The command-line arguments appear in this file as a set of
null-separated strings, with a further null byte after the last string.
.TP
.IR /proc/[number]/coredump_filter " (since kernel 2.6.23)"
See
.BR core (5).
.\" FIXME Describe /proc/[number]/cpuset and
.\" /proc/PID/task/TID/cpuset
.\" Added in 2.6.12
.\"
.TP
.I /proc/[number]/cwd
This is a symbolic link to the current working directory of the process.
To find out the cwd of process 20, for instance, you can do this:
@ -121,9 +149,8 @@ are not available if the main thread has already terminated
.I /proc/[number]/environ
This file contains the environment for the process.
The entries are separated by null bytes (\(aq\\0\(aq),
and there may be a null bytes at the end.
and there may be a null byte at the end.
Thus, to print out the environment of process 1, you would do:
.in +4n
.nf
@ -205,6 +232,41 @@ Most Linux MAKEDEV scripts symbolically link
/dev/fd to /proc/self/fd, in fact.
.\" FIXME Describe /proc/[number]/loginuid
.\" Added in 2.6.11; updating requires CAP_AUDIT_CONTROL
.\" CONFIG_AUDITSYSCALL
.TP
.I /proc/[number]/fdinfo/ " (since kernel 2.6.22)"
This is a subdirectory containing one entry for each file which the
process has open, named by its file descriptor.
The contents of each file can be read to obtain information
about the corresponding file descriptor, for example:
.in +4n
.nf
$ cat /proc/12015/fdinfo/4
pos: 1000
flags: 01002002
.fi
.in
The
.I pos
field is a decimal number showing the current file offset.
The
.I flags
field is an octal number that displays the
file access mode and file status flags (see
.BR open (2)).
The files in this directory are readable only by the owner of the process.
.\" FIXME document /proc/[number]/io
.\" .TP
.\" .IR /proc/[number]/io " (since kernel 2.6.20)"
.TP
.IR /proc/[number]/limits " (since kernel 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).
The file is protected to only allow reading by the real UID of the process.
.TP
.I /proc/[number]/maps
A file containing the currently mapped memory regions and their access
@ -255,21 +317,189 @@ This file can be used to access the pages of a process's memory through
.BR read (2),
and
.BR lseek (2).
.\" FIXME Describe /proc/[number]/mountstats and
.\" /proc/PID/task/TID/mountstats
.\" Some information can be found in the 2.6.17-rc1 change log.
.\" Added in 2.6.17
.\"
.\" FIXME Describe /proc/[number]/mountinfo and
.\" /proc/PID/task/TID/mountinfo
.\" Info in Documentation/filesystems/proc.txt
.\" Added in 2.6.26
.\"
.\" FIXME Describe /proc/[number]/oom_adj
.\" Added in 2.6.11; updating requires CAP_SYS_RESOURCE
.\" Mention OOM_DISABLE (-17)
.\" FIXME Describe /proc/[number]/oom_score
.\" Added in 2.6.11; read-only
.TP
.IR /proc/[number]/mountinfo " (since Linux 2.6.26)"
.\" This info adapted from Documentation/filesystems/proc.txt
This file contains information about mount points.
It contains lines of the form:
.nf
.ft CW
.in 8n
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)
.in
.ft
.fi
.IP
The numbers in parentheses are labels for the descriptions below:
.RS 12
.TP 5
(1)
mount ID: unique identifier of the mount (may be reused after
.BR umount (2)).
.TP
(2)
parent ID: ID of parent mount (or of self for the top of the mount tree).
.TP
(3)
major:minor: value of
.I st_dev
for files on file system (see
.BR stat (2)).
.TP
(4)
root: root of the mount within the file system.
.TP
(5)
mount point: mount point relative to the process's root.
.TP
(6)
mount options: per-mount options.
.TP
(7)
optional fields: zero or more fields of the form "tag[:value]".
.TP
(8)
separator: marks the end of the optional fields.
.TP
(9)
file system type: name of file system in the form "type[.subtype]".
.TP
(10)
mount source: file system-specific information or "none".
.TP
(11)
super options: per-super block options.
.RE
.IP
Parsers should ignore all unrecognized optional fields.
Currently the possible optional fields are:
.RS 12
.TP 18
shared:X
mount is shared in peer group X
.TP
master:X
mount is slave to peer group X
.TP
propagate_from:X
mount is slave and receives propagation from peer group X (*)
.TP
unbindable
mount is unbindable
.RE
.IP
(*) X is the closest dominant peer group under the process's root.
If X is the immediate master of the mount,
or if there is no dominant peer group under the same root,
then only the "master:X" field is present
and not the "propagate_from:X" field.
For more information on mount propagation see:
.I Documentation/filesystems/sharedsubtree.txt
in the kernel source tree.
.TP
.IR /proc/[number]/mountstats " (since Linux 2.6.17)"
This file system exports information (statistics, configuration information)
about the mount points in the process's name space.
Lines in this file have the form:
.nf
device /dev/sda7 mounted on /home with fstype ext3 [statistics]
( 1 ) ( 2 ) (3 ) (4)
.fi
.IP
The fields in each line are:
.RS 12
.TP 5
(1)
The name of the mounted device
(or "nodevice" if there is no corresponding device).
.TP
(2)
The mount point within the file system tree.
.TP
(3)
The file system type.
.TP
(4)
Optional statistics and configuration information.
Currently (as at Linux 2.6.26), only NFS file systems export
information via this field.
.RE
.IP
This file is only readable by the owner of the process.
.\"
.\" FIXME Describe /proc/[number]/mountstats and
.\" /proc/PID/task/TID/mountstats
.\" Some information can be found in the 2.6.17 change log.
.\" Added in 2.6.17
.\"
.TP
.IR /proc/[number]/oom_adj " (since Linux 2.6.11)"
.\" FIXME . probably the discussion of MAP_NORESERVE in mmap.2
.\" should point to the discussion of oom_adj and oom_score in this page.
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.
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.
.TP
.IR /proc/[number]/oom_score " (since Linux 2.6.11)"
.\" See mm/oom_kill.c::badness() in the 2.6.25 sources
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 the 2.6.25 sources
.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) (+);
.IP *
whether the process is privileged (\-); and
.\" More precisely, if it has CAP_SYS_ADMIN or CAP_SYS_RESOURCE
.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 bit-shift adjustment specified by the
.I oom_adj
setting for the process.
.\" FIXME Describe /proc/[number]/pagemap
.\" Added in 2.6.25
.\" CONFIG_PROC_PAGE_MONITOR
.TP
.I /proc/[number]/root
Unix and Linux support the idea of a per-process root of the
@ -286,8 +516,21 @@ are not available if the main thread has already terminated
.BR pthread_exit (3)).
.\" FIXME Describe /proc/[number]/seccomp
.\" Added in 2.6.12
.\" FIXME Describe /proc/[number]/sessionid
.\" Added in 2.6.25; read-only; only readable by real UID
.\" CONFIG_AUDITSYSCALL
.\" FIXME Describe /proc/[number]/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
.\" FIXME Describe /proc/[number]/schedstats and
.\" /proc/[number]/task/TID/schedstats
.\" Added in 2.6.9
.\" CONFIG_SCHEDSTATS
.TP
.IR /proc/[number]/smaps " (since Linux 2.6.14)"
.\" CONFIG_PROC_PAGE_MONITOR
This file shows memory consumption for each of the process's mappings.
For each of mappings there is a series of lines as follows:
.in +4n
@ -999,6 +1242,10 @@ It became once more non-optionally 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 /proc/sched_debug
.\" .TP
.\" .IR /proc/sched_debug " (since Linux 2.6.23)"
.\" See also /proc/PID/sched
.TP
.I /proc/scsi
A directory with the scsi mid-level pseudo-file and various SCSI low-level
@ -1839,6 +2086,14 @@ Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994
.ft
.in +2
.fi
.\" FIXME Document /proc/timer_list
.\" .TP
.\" .IR /proc/timer_list " (since Linux 2.6.21)"
.\" See the 2.6.21 Change log
.\" FIXME Document /proc/timer_stats
.\" .TP
.\" .IR /proc/timer_stats " (since Linux 2.6.21)"
.\" See the 2.6.21 Change log
.TP
.IR /proc/vmstat " (since Linux 2.6)"
This file displays various virtual memory statistics.