| .\" 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) |
| .\" and System V IPC (as well as various other) additions from |
| .\" Michael Kerrisk <mtk.manpages@gmail.com> |
| .\" |
| .\" This is free documentation; you can redistribute it and/or |
| .\" modify it under the terms of the GNU General Public License as |
| .\" published by the Free Software Foundation; either version 2 of |
| .\" the License, or (at your option) any later version. |
| .\" |
| .\" The GNU General Public License's references to "object code" |
| .\" and "executables" are to be interpreted as the output of any |
| .\" document formatting or typesetting system, including |
| .\" intermediate and printed output. |
| .\" |
| .\" This manual is distributed in the hope that it will be useful, |
| .\" but WITHOUT ANY WARRANTY; without even the implied warranty of |
| .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| .\" GNU General Public License for more details. |
| .\" |
| .\" You should have received a copy of the GNU General Public |
| .\" License along with this manual; if not, write to the Free |
| .\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, |
| .\" USA. |
| .\" |
| .\" Modified 1995-05-17 by faith@cs.unc.edu |
| .\" Minor changes by aeb and Marty Leisner (leisner@sdsp.mc.xerox.com). |
| .\" Modified 1996-04-13, 1996-07-22 by aeb@cwi.nl |
| .\" Modified 2001-12-16 by rwhron@earthlink.net |
| .\" Modified 2002-07-13 by jbelton@shaw.ca |
| .\" Modified 2002-07-22, 2003-05-27, 2004-04-06, 2004-05-25 |
| .\" by Michael Kerrisk <mtk.manpages@gmail.com> |
| .\" 2004-11-17, mtk -- updated notes on /proc/loadavg |
| .\" 2004-12-01, mtk, rtsig-max and rtsig-nr went away in 2.6.8 |
| .\" 2004-12-14, mtk, updated 'statm', and fixed error in order of list |
| .\" 2005-05-12, mtk, updated 'stat' |
| .\" 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. |
| .\" 2008-06-05, mtk, Added /proc/[pid]/oom_score, /proc/[pid]/oom_adj, |
| .\" /proc/[pid]/limits, /proc/[pid]/mountinfo, /proc/[pid]/mountstats, |
| .\" and /proc/[pid]/fdinfo/*. |
| .\" 2008-06-19, mtk, Documented /proc/[pid]/status. |
| .\" 2008-07-15, mtk, added /proc/config.gz |
| .\" |
| .\" FIXME 2.6.13 seems to have /proc/vmcore implemented |
| .\" in the source code, but there is no option available under |
| .\" 'make xconfig'; eventually this should be fixed, and then info |
| .\" from the patch-2.6.13 and change log could be used to write an |
| .\" entry in this man page. |
| .\" Needs CONFIG_VMCORE |
| .\" |
| .\" FIXME cross check against Documentation/filesystems/proc.txt |
| .\" to see what information could be imported from that file |
| .\" into this file. |
| .\" |
| .TH PROC 5 2012-12-27 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| proc \- process information pseudo-file system |
| .SH DESCRIPTION |
| The |
| .I proc |
| file system is a pseudo-file system which is used as an interface to |
| kernel data structures. |
| It is commonly mounted at |
| .IR /proc . |
| Most of it is read-only, but some files allow kernel variables to be |
| changed. |
| .LP |
| The following outline gives a quick tour through the |
| .I /proc |
| hierarchy. |
| .PD 1 |
| .TP |
| .I /proc/[pid] |
| 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/[pid]/attr and |
| .\" /proc/[pid]/task/[tid]/attr |
| .\" This is a directory |
| .\" Added in ??? |
| .\" CONFIG_SECURITY |
| .\" |
| .TP |
| .IR /proc/[pid]/auxv " (since 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. |
| .TP |
| .IR /proc/[pid]/cgroup " (since Linux 2.6.24)" |
| .\" Info in Documentation/cgroups/cgroups.txt |
| This file describes control groups to which the process/task belongs. |
| For each cgroup hierarchy there is one entry containing |
| colon-separated fields of the form: |
| .nf |
| .ft CW |
| |
| 5:cpuacct,cpu,cpuset:/daemons |
| .ft |
| .fi |
| .IP |
| The colon-separated fields are, from left to right: |
| .RS 11 |
| .IP 1. 3 |
| hierarchy ID number |
| .IP 2. |
| set of subsystems bound to the hierarchy |
| .IP 3. |
| control group in the hierarchy to which the process belongs |
| .RE |
| .IP |
| This file is only present if the |
| .B CONFIG_CGROUPS |
| kernel configuration option is enabled. |
| .\" |
| .\" FIXME Describe /proc/[pid]/clear_refs |
| .\" Added in 2.6.22 |
| .\" "Clears page referenced bits shown in smaps output" |
| .\" write-only |
| .\" CONFIG_PROC_PAGE_MONITOR |
| .TP |
| .I /proc/[pid]/cmdline |
| This 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\\0\(aq), |
| with a further null byte after the last string. |
| .TP |
| .IR /proc/[pid]/coredump_filter " (since kernel 2.6.23)" |
| See |
| .BR core (5). |
| .TP |
| .IR /proc/[pid]/cpuset " (since kernel 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: |
| |
| .in +4n |
| .nf |
| .RB "$" " cd /proc/20/cwd; /bin/pwd" |
| .fi |
| .in |
| |
| Note that the |
| .I pwd |
| command is often a shell built-in, and might |
| not work properly. |
| In |
| .BR bash (1), |
| you may use |
| .IR "pwd\ \-P" . |
| |
| .\" 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)). |
| .TP |
| .I /proc/[pid]/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 byte at the end. |
| Thus, to print out the environment of process 1, you would do: |
| .in +4n |
| .nf |
| |
| .ft CW |
| .RB "$" " (cat /proc/1/environ; echo) | tr \(aq\e000\(aq \(aq\en\(aq" |
| .fi |
| .ft P |
| .in |
| .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 as is being run by |
| process [pid]. |
| .\" 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)). |
| |
| 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: |
| |
| [device]:inode |
| |
| For example, [0301]:1502 would be inode 1502 on device major 03 (IDE, |
| MFM, etc. drives) minor 01 (first partition on the first drive). |
| |
| .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, etc. |
| |
| .\" 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)). |
| |
| Programs that will take a filename as a command-line argument, |
| but will not take input from standard input if no argument is supplied, |
| or that write to a file named as a command-line argument, |
| but will not send their output to standard output |
| if no argument is supplied, can nevertheless be made to use |
| standard input or standard out using |
| .IR /proc/[pid]/fd . |
| For example, assuming that |
| .I \-i |
| is the flag designating an input file and |
| .I \-o |
| is the flag designating an output file: |
| .in +4n |
| .nf |
| |
| .RB "$" " foobar \-i /proc/self/fd/0 \-o /proc/self/fd/1 ..." |
| .fi |
| .in |
| |
| and you have a working filter. |
| .\" The following is not true in my tests (MTK): |
| .\" Note that this will not work for |
| .\" programs that seek on their files, as the files in the fd directory |
| .\" are not seekable. |
| |
| .I /proc/self/fd/N |
| is approximately the same as |
| .I /dev/fd/N |
| in some UNIX and UNIX-like systems. |
| Most Linux MAKEDEV scripts symbolically link |
| .I /dev/fd |
| to |
| .IR /proc/self/fd , |
| in fact. |
| |
| Most systems provide symbolic links |
| .IR /dev/stdin , |
| .IR /dev/stdout , |
| and |
| .IR /dev/stderr , |
| which respectively link to the files |
| .IR 0 , |
| .IR 1 , |
| and |
| .IR 2 |
| in |
| .IR /proc/self/fd . |
| Thus the example command above could be written as: |
| .in +4n |
| .nf |
| |
| .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..." |
| .fi |
| .in |
| .\" FIXME Describe /proc/[pid]/loginuid |
| .\" Added in 2.6.11; updating requires CAP_AUDIT_CONTROL |
| .\" CONFIG_AUDITSYSCALL |
| .TP |
| .IR /proc/[pid]/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 |
| |
| .RB "$" " 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/[pid]/io |
| .\" .TP |
| .\" .IR /proc/[pid]/io " (since kernel 2.6.20)" |
| .TP |
| .IR /proc/[pid]/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)). |
| Up to and including Linux 2.6.35, |
| this file is protected to only allow reading by the real UID of the process. |
| Since Linux 2.6.36, |
| .\" commit 3036e7b490bf7878c6dae952eec5fb87b1106589 |
| this file is readable by all users on the system. |
| .TP |
| .I /proc/[pid]/maps |
| A file containing the currently mapped memory regions and their access |
| permissions. |
| |
| The format is: |
| |
| .nf |
| .ft CW |
| address perms offset dev inode pathname |
| 08048000-08056000 r-xp 00000000 03:0c 64593 /usr/sbin/gpm |
| 08056000-08058000 rw-p 0000d000 03:0c 64593 /usr/sbin/gpm |
| 08058000-0805b000 rwxp 00000000 00:00 0 |
| 40000000-40013000 r-xp 00000000 03:0c 4165 /lib/ld-2.2.4.so |
| 40013000-40015000 rw-p 00012000 03:0c 4165 /lib/ld-2.2.4.so |
| 4001f000-40135000 r-xp 00000000 03:0c 45494 /lib/libc-2.2.4.so |
| 40135000-4013e000 rw-p 00115000 03:0c 45494 /lib/libc-2.2.4.so |
| 4013e000-40142000 rw-p 00000000 00:00 0 |
| bffff000-c0000000 rwxp 00000000 00:00 0 |
| .ft |
| .fi |
| |
| where "address" is the address space in the process that it occupies, |
| "perms" is a set of permissions: |
| |
| .nf |
| .in +5 |
| r = read |
| w = write |
| x = execute |
| s = shared |
| p = private (copy on write) |
| .fi |
| .in |
| |
| "offset" is the offset into the file/whatever, "dev" is the device |
| (major:minor), and "inode" is the inode on that device. |
| 0 indicates that no inode is associated with the memory region, |
| as the case would be with BSS (uninitialized data). |
| |
| 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). |
| .TP |
| .IR /proc/[pid]/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 |
| |
| 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) |
| .ft |
| .fi |
| .IP |
| The numbers in parentheses are labels for the descriptions below: |
| .RS 7 |
| .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 Linux kernel source tree. |
| .TP |
| .IR /proc/[pid]/mounts " (since Linux 2.4.19)" |
| This is a list of all the file systems currently mounted in the |
| process's mount namespace. |
| The format of this file is documented in |
| .BR fstab (5). |
| Since kernel version 2.6.15, this file is pollable: |
| after opening the file for reading, a change in this file |
| (i.e., a file system mount or unmount) causes |
| .BR select (2) |
| to mark the file descriptor as readable, and |
| .BR poll (2) |
| and |
| .BR epoll_wait (2) |
| mark the file as having an error condition. |
| .TP |
| .IR /proc/[pid]/mountstats " (since Linux 2.6.17)" |
| This file 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 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 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. |
| .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 information about namespaces, see |
| .BR clone (2). |
| .TP |
| .IR /proc/[pid]/ns/ipc " (since Linux 3.0)" |
| Bind mounting this file (see |
| .BR mount (2)) |
| to somewhere else in the filesystem keeps |
| the IPC namespace of the process specified by |
| .I pid |
| alive even if all processes currently in the namespace terminate. |
| |
| Opening this file returns a file handle for the IPC namespace |
| of the process specified by |
| .IR pid . |
| As long as this file descriptor remains open, |
| the IPC namespace will remain alive, |
| even if all processes in the namespace terminate. |
| The file descriptor can be passed to |
| .BR setns (2). |
| .TP |
| .IR /proc/[pid]/ns/net " (since Linux 3.0)" |
| Bind mounting this file (see |
| .BR mount (2)) |
| to somewhere else in the filesystem keeps |
| the network namespace of the process specified by |
| .I pid |
| alive even if all processes in the namespace terminate. |
| |
| Opening this file returns a file handle for the network namespace |
| of the process specified by |
| .IR pid . |
| As long as this file descriptor remains open, |
| the network namespace will remain alive, |
| even if all processes in the namespace terminate. |
| The file descriptor can be passed to |
| .BR setns (2). |
| .TP |
| .IR /proc/[pid]/ns/uts " (since Linux 3.0)" |
| Bind mounting this file (see |
| .BR mount (2)) |
| to somewhere else in the filesystem keeps |
| the UTS namespace of the process specified by |
| .I pid |
| alive even if all processes currently in the namespace terminate. |
| |
| Opening this file returns a file handle for the UTS namespace |
| of the process specified by |
| .IR pid . |
| As long as this file descriptor remains open, |
| the UTS namespace will remain alive, |
| even if all processes in the namespace terminate. |
| The file descriptor can be passed to |
| .BR setns (2). |
| .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 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 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. |
| |
| 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. |
| |
| There is an additional factor included in the badness score: root |
| processes are given 3% extra memory over other tasks. |
| |
| 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. |
| |
| 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 killink. |
| 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. |
| |
| Consequently, it is very simple for user space to define |
| the amount of memory to consider for each task. |
| Setting a |
| .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. |
| |
| For backwards 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 . |
| |
| Writing to |
| .IR /proc/[pid]/oom_score_adj |
| or |
| .IR /proc/[pid]/oom_adj |
| will change the other with its scaled value. |
| .\" FIXME Describe /proc/[pid]/pagemap |
| .\" Added in 2.6.25 |
| .\" CONFIG_PROC_PAGE_MONITOR |
| .TP |
| .I /proc/[pid]/root |
| UNIX and Linux support the idea of a per-process root of the |
| file system, set by the |
| .BR chroot (2) |
| system call. |
| This file is a symbolic link that points to the process's |
| root directory, and behaves as exe, fd/*, etc. do. |
| |
| .\" 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)). |
| .\" FIXME Describe /proc/[pid]/seccomp |
| .\" Added in 2.6.12 |
| .\" FIXME Describe /proc/[pid]/sessionid |
| .\" Added in 2.6.25; read-only; only readable by real UID |
| .\" CONFIG_AUDITSYSCALL |
| .\" 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 |
| .\" FIXME Describe /proc/[pid]/schedstats and |
| .\" /proc/[pid]/task/[tid]/schedstats |
| .\" Added in 2.6.9 |
| .\" CONFIG_SCHEDSTATS |
| .TP |
| .IR /proc/[pid]/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 such as the following: |
| .in +4n |
| .nf |
| |
| 08048000-080bc000 r-xp 00000000 03:02 13130 /bin/bash |
| Size: 464 kB |
| Rss: 424 kB |
| Shared_Clean: 424 kB |
| Shared_Dirty: 0 kB |
| Private_Clean: 0 kB |
| Private_Dirty: 0 kB |
| |
| .fi |
| .in |
| The first of these lines shows the same information as is displayed |
| for the mapping in |
| .IR /proc/[pid]/maps . |
| The remaining lines show the size of the mapping, |
| the amount of the mapping that is currently resident in RAM, |
| the number of clean and dirty shared pages in the mapping, |
| and the number of clean and dirty private pages in the mapping. |
| |
| This file is only present if the |
| .B CONFIG_MMU |
| kernel configuration |
| option is enabled. |
| .TP |
| .I /proc/[pid]/stat |
| Status information about the process. |
| This is used by |
| .BR ps (1). |
| It is defined in |
| .IR /usr/src/linux/fs/proc/array.c "." |
| |
| The fields, in order, with their proper |
| .BR scanf (3) |
| format specifiers, are: |
| .RS |
| .TP 12 |
| \fIpid\fP %d |
| (1) The process ID. |
| .TP |
| \fIcomm\fP %s |
| (2) The filename of the executable, in parentheses. |
| This is visible whether or not the executable is swapped out. |
| .TP |
| \fIstate\fP %c |
| (3) One character from the string "RSDZTW" where R is running, S is |
| sleeping in an interruptible wait, D is waiting in uninterruptible |
| disk sleep, Z is zombie, T is traced or stopped (on a signal), |
| and W is paging. |
| .TP |
| \fIppid\fP %d |
| (4) The PID of the parent. |
| .TP |
| \fIpgrp\fP %d |
| (5) The process group ID of the process. |
| .TP |
| \fIsession\fP %d |
| (6) The session ID of the process. |
| .TP |
| \fItty_nr\fP %d |
| (7) 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 |
| \fItpgid\fP %d |
| .\" This field and following, up to and including wchan added 0.99.1 |
| (8) The ID of the foreground process group of the controlling |
| terminal of the process. |
| .TP |
| \fIflags\fP %u (%lu before Linux 2.6.22) |
| (9) 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. |
| .TP |
| \fIminflt\fP %lu |
| (10) The number of minor faults the process has made which have not |
| required loading a memory page from disk. |
| .TP |
| .\" field 11 |
| \fIcminflt\fP %lu |
| (11) The number of minor faults that the process's |
| waited-for children have made. |
| .TP |
| \fImajflt\fP %lu |
| (12) The number of major faults the process has made which have |
| required loading a memory page from disk. |
| .TP |
| \fIcmajflt\fP %lu |
| (13) The number of major faults that the process's |
| waited-for children have made. |
| .TP |
| \fIutime\fP %lu |
| (14) 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 |
| \fIstime\fP %lu |
| (15) Amount of time that this process has been scheduled in kernel mode, |
| measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .TP |
| \fIcutime\fP %ld |
| (16) 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 |
| \fIcstime\fP %ld |
| (17) 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 |
| \fIpriority\fP %ld |
| (18) (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. |
| |
| 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 |
| \fInice\fP %ld |
| (19) 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 |
| \fInum_threads\fP %ld |
| (20) 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 |
| .\" field 21 |
| \fIitrealvalue\fP %ld |
| (21) 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 |
| \fIstarttime\fP %llu (was %lu before Linux 2.6) |
| (22) 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) ). |
| .TP |
| \fIvsize\fP %lu |
| (23) Virtual memory size in bytes. |
| .TP |
| \fIrss\fP %ld |
| (24) 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. |
| .TP |
| \fIrsslim\fP %lu |
| (25) Current soft limit in bytes on the rss of the process; |
| see the description of |
| .B RLIMIT_RSS |
| in |
| .BR getrlimit (2). |
| .TP |
| \fIstartcode\fP %lu |
| (26) The address above which program text can run. |
| .TP |
| \fIendcode\fP %lu |
| (27) The address below which program text can run. |
| .TP |
| \fIstartstack\fP %lu |
| (28) The address of the start (i.e., bottom) of the stack. |
| .TP |
| \fIkstkesp\fP %lu |
| (29) The current value of ESP (stack pointer), as found in the |
| kernel stack page for the process. |
| .TP |
| \fIkstkeip\fP %lu |
| (30) The current EIP (instruction pointer). |
| .TP |
| .\" field 31 |
| \fIsignal\fP %lu |
| (31) 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 |
| \fIblocked\fP %lu |
| (32) 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 |
| \fIsigignore\fP %lu |
| (33) 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 |
| \fIsigcatch\fP %lu |
| (34) 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 |
| \fIwchan\fP %lu |
| (35) This is the "channel" in which the process is waiting. |
| It is the |
| address of a system call, and can be looked up in a namelist if you |
| need a textual name. |
| (If you have an up-to-date |
| .IR /etc/psdatabase , |
| then |
| try \fIps \-l\fP to see the WCHAN field in action.) |
| .TP |
| \fInswap\fP %lu |
| (36) .\" nswap was added in 2.0 |
| Number of pages swapped (not maintained). |
| .TP |
| \fIcnswap\fP %lu |
| (37) .\" cnswap was added in 2.0 |
| Cumulative \fInswap\fP for child processes (not maintained). |
| .TP |
| \fIexit_signal\fP %d (since Linux 2.1.22) |
| (38) Signal to be sent to parent when we die. |
| .TP |
| \fIprocessor\fP %d (since Linux 2.2.8) |
| (39) CPU number last executed on. |
| .TP |
| \fIrt_priority\fP %u (since Linux 2.5.19; was %lu before Linux 2.6.22) |
| (40) 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 |
| .\" field 41 |
| \fIpolicy\fP %u (since Linux 2.5.19; was %lu before Linux 2.6.22) |
| (41) Scheduling policy (see |
| .BR sched_setscheduler (2)). |
| Decode using the SCHED_* constants in |
| .IR linux/sched.h . |
| .TP |
| \fIdelayacct_blkio_ticks\fP %llu (since Linux 2.6.18) |
| (42) Aggregated block I/O delays, measured in clock ticks (centiseconds). |
| .TP |
| \fIguest_time\fP %lu (since Linux 2.6.24) |
| (43) 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 |
| \fIcguest_time\fP %ld (since Linux 2.6.24) |
| (44) Guest time of the process's children, measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .RE |
| .TP |
| .I /proc/[pid]/statm |
| Provides information about memory usage, measured in pages. |
| The columns are: |
| .in +4n |
| .nf |
| |
| size (1) total program size |
| (same as VmSize in \fI/proc/[pid]/status\fP) |
| resident (2) resident set size |
| (same as VmRSS in \fI/proc/[pid]/status\fP) |
| share (3) shared pages (i.e., backed by a file) |
| text (4) text (code) |
| .\" (not including libs; broken, includes data segment) |
| lib (5) library (unused in Linux 2.6) |
| data (6) data + stack |
| .\" (including libs; broken, includes library text) |
| dt (7) dirty pages (unused in Linux 2.6) |
| .fi |
| .in |
| .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: |
| .in +4n |
| .nf |
| |
| .RB "$" " cat /proc/$$/status" |
| Name: bash |
| State: S (sleeping) |
| Tgid: 3515 |
| Pid: 3515 |
| PPid: 3452 |
| TracerPid: 0 |
| Uid: 1000 1000 1000 1000 |
| Gid: 100 100 100 100 |
| FDSize: 256 |
| Groups: 16 33 100 |
| VmPeak: 9136 kB |
| VmSize: 7896 kB |
| VmLck: 0 kB |
| VmHWM: 7572 kB |
| VmRSS: 6316 kB |
| VmData: 5224 kB |
| VmStk: 88 kB |
| VmExe: 572 kB |
| VmLib: 1708 kB |
| VmPTE: 20 kB |
| Threads: 1 |
| SigQ: 0/3067 |
| SigPnd: 0000000000000000 |
| ShdPnd: 0000000000000000 |
| SigBlk: 0000000000010000 |
| SigIgn: 0000000000384004 |
| SigCgt: 000000004b813efb |
| CapInh: 0000000000000000 |
| CapPrm: 0000000000000000 |
| CapEff: 0000000000000000 |
| CapBnd: ffffffffffffffff |
| Cpus_allowed: 00000001 |
| Cpus_allowed_list: 0 |
| Mems_allowed: 1 |
| Mems_allowed_list: 0 |
| voluntary_ctxt_switches: 150 |
| nonvoluntary_ctxt_switches: 545 |
| .fi |
| .in |
| .IP |
| The fields are as follows: |
| .RS |
| .IP * 2 |
| .IR Name : |
| Command run by this process. |
| .IP * |
| .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)". |
| .IP * |
| .IR Tgid : |
| Thread group ID (i.e., Process ID). |
| .IP * |
| .IR Pid : |
| Thread ID (see |
| .BR gettid (2)). |
| .IP * |
| .IR PPid : |
| PID of parent process. |
| .IP * |
| .IR TracerPid : |
| PID of process tracing this process (0 if not being traced). |
| .IP * |
| .IR Uid ", " Gid : |
| Real, effective, saved set, and file system UIDs (GIDs). |
| .IP * |
| .IR FDSize : |
| Number of file descriptor slots currently allocated. |
| .IP * |
| .IR Groups : |
| Supplementary group list. |
| .IP * |
| .IR VmPeak : |
| Peak virtual memory size. |
| .IP * |
| .IR VmSize : |
| Virtual memory size. |
| .IP * |
| .IR VmLck : |
| Locked memory size (see |
| .BR mlock (3)). |
| .IP * |
| .IR VmHWM : |
| Peak resident set size ("high water mark"). |
| .IP * |
| .IR VmRSS : |
| Resident set size. |
| .IP * |
| .IR VmData ", " VmStk ", " VmExe : |
| Size of data, stack, and text segments. |
| .IP * |
| .IR VmLib : |
| Shared library code size. |
| .IP * |
| .IR VmPTE : |
| Page table entries size (since Linux 2.6.10). |
| .IP * |
| .IR Threads : |
| Number of threads in process containing this thread. |
| .IP * |
| .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)). |
| .IP * |
| .IR SigPnd ", " ShdPnd : |
| Number of signals pending for thread and for process as a whole (see |
| .BR pthreads (7) |
| and |
| .BR signal (7)). |
| .IP * |
| .IR SigBlk ", " SigIgn ", " SigCgt : |
| Masks indicating signals being blocked, ignored, and caught (see |
| .BR signal (7)). |
| .IP * |
| .IR CapInh ", " CapPrm ", " CapEff : |
| Masks of capabilities enabled in inheritable, permitted, and effective sets |
| (see |
| .BR capabilities (7)). |
| .IP * |
| .IR CapBnd : |
| Capability Bounding set |
| (since kernel 2.6.26, see |
| .BR capabilities (7)). |
| .IP * |
| .IR Cpus_allowed : |
| Mask of CPUs on which this process may run |
| (since Linux 2.6.24, see |
| .BR cpuset (7)). |
| .IP * |
| .IR Cpus_allowed_list : |
| Same as previous, but in "list format" |
| (since Linux 2.6.26, see |
| .BR cpuset (7)). |
| .IP * |
| .IR Mems_allowed : |
| Mask of memory nodes allowed to this process |
| (since Linux 2.6.24, see |
| .BR cpuset (7)). |
| .IP * |
| .IR Mems_allowed_list : |
| Same as previous, but in "list format" |
| (since Linux 2.6.26, see |
| .BR cpuset (7)). |
| .IP * |
| .IR voluntary_context_switches ", " nonvoluntary_context_switches : |
| Number of voluntary and involuntary context switches (since Linux 2.6.23). |
| .RE |
| .TP |
| .IR /proc/[pid]/task " (since 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)). |
| 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). |
| |
| .\" 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 |
| .I /proc/apm |
| Advanced power management version and battery information when |
| .B CONFIG_APM |
| is defined at kernel compilation time. |
| .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 |
| .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), |
| .BR zgrep (1), |
| etc. |
| 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 : |
| .in +4n |
| .nf |
| |
| cat /lib/modules/$(uname \-r)/build/.config |
| .fi |
| .in |
| .IP |
| .I /proc/config.gz |
| is only provided if the kernel is configured with |
| .BR CONFIG_IKCONFIG_PROC . |
| .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. |
| .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/iostats.txt |
| 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 file systems which are supported by the kernel, |
| namely file systems which were compiled into the kernel or whose kernel |
| modules are currently loaded. |
| (See also |
| .BR filesystems (5).) |
| If a file system is marked with "nodev", |
| this means that it does not require a block device to be mounted |
| (e.g., virtual file system, network file system). |
| |
| Incidentally, this file may be used by |
| .BR mount (8) |
| when no file system is specified and it didn't manage to determine the |
| file system type. |
| Then file systems contained in this file are tried |
| (excepted those that are marked with "nodev"). |
| .TP |
| .I /proc/fs |
| Empty subdirectory. |
| .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: |
| |
| .in +4n |
| .nf |
| 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's model number |
| settings drive settings |
| smart_thresholds in hexadecimal |
| smart_values in hexadecimal |
| .fi |
| .in |
| |
| 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. |
| |
| The total length of the file is the size of physical memory (RAM) plus |
| 4KB. |
| .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. |
| |
| Information in this file is retrieved with the |
| .BR dmesg (1) |
| program. |
| .TP |
| .IR /proc/ksyms " (Linux 1.1.23-2.5.47)" |
| 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)). |
| .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 only present 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 fileds are only displayed 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 Buffers " %lu" |
| Relatively temporary storage for raw disk blocks that |
| shouldn't get tremendously large (20MB 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 ~860MB 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 mmaped, such as libraries. |
| .TP |
| .IR Shmem " %lu (since Linux 2.6.32)" |
| [To be documented.] |
| .TP |
| .IR Slab " %lu" |
| In-kernel data structures cache. |
| .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)" |
| Based on the overcommit ratio ('vm.overcommit_ratio'), |
| this is the total amount of memory currently available to |
| be allocated on the system. This limit is only adhered to |
| if strict overcommit accounting is enabled (mode 2 in |
| .IR /proc/sys/vm/overcommit_ratio ). |
| The |
| .I CommitLimit |
| is calculated using the following formula: |
| |
| CommitLimit = (overcommit_ratio * Physical RAM) + Swap |
| |
| For example, on a system with 1GB of physical RAM and 7GB |
| of swap with a |
| .I overcommit_ratio |
| of 30, this formula yields a |
| .I CommitLimit |
| of 7.3GB. |
| For more details, see the memory overcommit documentation |
| in the kernel source file |
| .IR Documentation/vm/overcommit-accounting . |
| .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 1GB of memory (using |
| .BR malloc (3) |
| or similar), but only touches 300MB of that memory will only show up |
| as using 300MB of memory even if it has the address space |
| allocated for the entire 1GB. |
| This 1GB 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 |
| .IR /proc/sys/vm/overcommit_memory ), |
| allocations which would exceed the |
| .I CommitLimit |
| (detailed above) 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. |
| .TP |
| .IR VmallocChunk " %lu" |
| Largest contiguous block of vmalloc area which is free. |
| .TP |
| .IR HardwareCorrupted " %lu (since Linux 2.6.32)" |
| (\fBCONFIG_MEMORY_FAILURE\fP is required.) |
| [To be documented.] |
| .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 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. |
| .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 file systems currently mounted on the system. |
| With the introduction of per-process mount namespaces in |
| Linux 2.4.19, this file became a link to |
| .IR /proc/self/mounts , |
| which lists the mount points 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/mtrr.txt |
| for details. |
| .TP |
| .I /proc/net |
| various net pseudo-files, all of which give the status of some part of |
| the networking layer. |
| These 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. |
| .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: |
| |
| .nf |
| .ft CW |
| .in 8n |
| 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 |
| .ft |
| .fi |
| .in |
| |
| 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: |
| |
| .nf |
| .ft CW |
| .in 1n |
| 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 |
| .in |
| .ft |
| .fi |
| .\" .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 : |
| .nf |
| .in +5 |
| indx interface_name dmi_u dmi_g dmi_address |
| 2 eth0 1 0 01005e000001 |
| 3 eth1 1 0 01005e000001 |
| 4 eth2 1 0 01005e000001 |
| .in |
| .fi |
| .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 only useful 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: |
| |
| .nf |
| .ft CW |
| .in 1n |
| 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 |
| .in |
| .ft |
| .fi |
| .TP |
| .I /proc/net/unix |
| Lists the UNIX domain sockets present within the system and their |
| status. |
| The format is: |
| .nf |
| .sp .5 |
| .ft CW |
| Num RefCount Protocol Flags Type St Path |
| 0: 00000002 00000000 00000000 0001 03 |
| 1: 00000001 00000000 00010000 0001 01 /dev/printer |
| .ft |
| .sp .5 |
| .fi |
| |
| Here "Num" is the kernel table slot number, "RefCount" is the number |
| of users of the socket, "Protocol" is currently always 0, "Flags" |
| represent the internal kernel flags holding the status of the |
| socket. |
| Currently, type is always "1" (UNIX domain datagram sockets are |
| not yet supported in the kernel). |
| \&"St" is the internal state of the |
| socket and Path is the bound path (if any) of the socket. |
| .TP |
| .I /proc/partitions |
| Contains major and minor numbers of each partition as well as number |
| of blocks and partition name. |
| .TP |
| .I /proc/pci |
| This is a listing of all PCI devices found during kernel initialization |
| and their configuration. |
| |
| 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 /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 |
| .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). |
| |
| 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. |
| |
| The command |
| .in +4n |
| .nf |
| |
| echo \(aqscsi add-single-device 1 0 5 0\(aq > /proc/scsi/scsi |
| |
| .fi |
| .in |
| 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. |
| |
| Reading these files will usually show driver and host configuration, |
| statistics, etc. |
| |
| 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 |
| file system, |
| 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. |
| Since Linux 2.6.16 this file is only present if the |
| .B CONFIG_SLAB |
| kernel configuration option is enabled. |
| The columns in |
| .I /proc/slabinfo |
| are: |
| .in +4n |
| .nf |
| |
| cache-name |
| num-active-objs |
| total-objs |
| object-size |
| num-active-slabs |
| total-slabs |
| num-pages-per-slab |
| .fi |
| .in |
| |
| See |
| .BR slabinfo (5) |
| for details. |
| .TP |
| .I /proc/stat |
| kernel/system statistics. |
| Varies with architecture. |
| Common |
| entries include: |
| .RS |
| .TP |
| \fIcpu 3357 0 4313 1362393\fP |
| 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 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. |
| .TP |
| .IR irq " (since Linux 2.6.0-test4)" |
| (6) Time servicing interrupts. |
| .TP |
| .I softirq " (since 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) The 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; |
| each subsequent column is the total for a particular interrupt. |
| .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.) |
| .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 sometimes modified using |
| the \fI/proc\fP file system, and the (deprecated) |
| .BR sysctl (2) |
| system call. |
| .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.txt |
| 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 file systems. |
| .TP |
| .I /proc/sys/fs/binfmt_misc |
| Documentation for files in this directory can be found |
| in the Linux kernel sources in |
| .IR Documentation/binfmt_misc.txt . |
| .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. |
| (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 about running out of file handles, |
| try increasing this value: |
| .br |
| |
| .br |
| .nf |
| .ft CW |
| echo 100000 > /proc/sys/fs/file-max |
| .fi |
| .ft |
| |
| The kernel constant |
| .B NR_OPEN |
| imposes an upper limit on the value that may be placed in |
| .IR file-max . |
| |
| If you increase |
| .IR /proc/sys/fs/file-max "," |
| be sure to increase |
| .I /proc/sys/fs/inode-max |
| to 3-4 times the new |
| value of |
| .IR /proc/sys/fs/file-max "," |
| or you will run out of inodes. |
| |
| Privileged processes |
| .RB ( CAP_SYS_ADMIN ) |
| can override the |
| .I file-max |
| limit. |
| .TP |
| .I /proc/sys/fs/file-nr |
| This (read-only) file gives the number of files presently opened. |
| It contains three numbers: the number of allocated file handles; |
| the number of free file handles; and the maximum number of file handles. |
| The kernel allocates file handles dynamically, but it |
| doesn't free them again. |
| If the number of allocated files is close to the |
| maximum, you should consider increasing the maximum. |
| When the number of free file handles is |
| large, you've encountered a peak in your usage of file |
| handles and you probably don't need to increase the maximum. |
| .TP |
| .I /proc/sys/fs/inode-max |
| This file contains the maximum number of in-memory inodes. |
| On some (2.4) systems, it may not be present. |
| This value should be 3-4 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. |
| .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. |
| .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. |
| .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. |
| .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/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/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 file systems only support 16-bit UIDs and GIDs, although in Linux |
| UIDs and GIDs are 32 bits. |
| When one of these file systems 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)" |
| The value in this file defines an upper limit for raising the capacity |
| of a pipe using the |
| .BR fcntl (2) |
| .B F_SETPIPE_SZ |
| operation. |
| This limit applies only to unprivileged processes. |
| The default value for this file is 1,048,576. |
| The value assigned to this file may be rounded upward, |
| to reflect the value actually employed for a convenient implementation. |
| To determine the rounded-up value, |
| display the contents of this file after assigning a value to it. |
| The minimum value that can be assigned to this file is the system page size. |
| .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 behaviour 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 caller has the |
| .BR CAP_FOWNER |
| capability. |
| .IP * |
| The file system UID of the process creating the link matches |
| the owner (UID) of the target file |
| (as described in |
| .BR credentials (7), |
| a process's file system 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 permission bit enabled; |
| .IP \(bu |
| the target file does not have both its set-group-ID and |
| group-executable permission 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_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 behaviour 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 file system UID of the process following the link matches |
| the owner (UID) of the symbolic link |
| (as described in |
| .BR credentials (7), |
| a process's file system 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 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 determines whether core dump files are |
| produced for set-user-ID or otherwise protected/tainted binaries. |
| Three different integer values can be specified: |
| .sp |
| \fI0\ (default)\fP |
| 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. |
| .sp |
| \fI1\ ("debug")\fP |
| All processes dump core when possible. |
| The core dump is owned by the file system user ID of the dumping process |
| and no security is applied. |
| This is intended for system debugging situations only. |
| Ptrace is unchecked. |
| .sp |
| \fI2\ ("suidsafe")\fP |
| 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. |
| .TP |
| .I /proc/sys/fs/super-max |
| This file |
| controls the maximum number of superblocks, and |
| thus the maximum number of mounted file systems the kernel |
| can have. |
| You only need to increase |
| .I super-max |
| if you need to mount more file systems than the current value in |
| .I super-max |
| allows you to. |
| .TP |
| .I /proc/sys/fs/super-nr |
| This file |
| contains the number of file systems 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 file system 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/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_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 (8) |
| 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: |
| |
| .in +4n |
| .nf |
| .RB "#" " echo \(aqdarkstar\(aq > /proc/sys/kernel/hostname" |
| .RB "#" " echo \(aqmydomain\(aq > /proc/sys/kernel/domainname" |
| .fi |
| .in |
| |
| has the same effect as |
| |
| .in +4n |
| .nf |
| .RB "#" " hostname \(aqdarkstar\(aq" |
| .RB "#" " domainname \(aqmydomain\(aq" |
| .fi |
| .in |
| |
| 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 path for the hotplug policy agent. |
| The default value in this file is |
| .IR /sbin/hotplug . |
| .TP |
| .I /proc/sys/kernel/htab-reclaim |
| (PowerPC only) If this file is set to a nonzero value, |
| the PowerPC htab |
| (see kernel file |
| .IR Documentation/powerpc/ppc_htab.txt ) |
| is pruned |
| each time the system hits the idle loop. |
| .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. |
| .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 path for the kernel module loader. |
| The default value is |
| .IR /sbin/modprobe . |
| The file is only present 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 |
| (only present 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 only present if the kernel is built with the |
| .B CONFIG_MODULES |
| option enabled. |
| .TP |
| .I /proc/sys/kernel/msgmax |
| 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 |
| .I /proc/sys/kernel/msgmni |
| This file defines the system-wide limit on the number of |
| message queue identifiers. |
| (This file is only present in Linux 2.4 onward.) |
| .TP |
| .I /proc/sys/kernel/msgmnb |
| 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/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). |
| 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 |
| The four values in this file are |
| .IR console_loglevel , |
| .IR default_message_loglevel , |
| .IR minimum_console_level , |
| and |
| .IR default_console_loglevel . |
| These values influence |
| .I printk() |
| behavior when printing or logging error messages. |
| See |
| .BR syslog (2) |
| for more info on the different loglevels. |
| Messages with a higher priority than |
| .I console_loglevel |
| will be printed to the console. |
| Messages without an explicit priority will be printed with priority |
| .IR default_message_level . |
| .I minimum_console_loglevel |
| is the minimum (highest) value to which |
| .I console_loglevel |
| can be set. |
| .I default_console_loglevel |
| is the default value for |
| .IR console_loglevel . |
| .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. |
| .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 |
| .I /proc/sys/kernel/real-root-dev |
| This file is documented in the Linux kernel source file |
| .IR Documentation/initrd.txt . |
| .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 POSIX real-time signals currently queued. |
| .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 |
| .I /proc/sys/kernel/shmall |
| This file |
| contains the system-wide limit on the total number of pages of |
| System V shared memory. |
| .TP |
| .I /proc/sys/kernel/shmmax |
| 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 1GB are now supported in the |
| kernel. |
| This value defaults to |
| .BR SHMMAX . |
| .TP |
| .I /proc/sys/kernel/shmmni |
| (available in Linux 2.4 and onward) |
| This file |
| specifies the system-wide maximum number of System V shared memory |
| segments that can be created. |
| .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: |
| |
| 0 - disable sysrq completely |
| 1 - enable all functions of sysrq |
| >1 - bitmask of allowed sysrq functions, as follows: |
| 2 - enable control of console logging level |
| 4 - enable control of keyboard (SAK, unraw) |
| 8 - enable debugging dumps of processes etc. |
| 16 - enable sync command |
| 32 - enable remount read-only |
| 64 - enable signalling of processes (term, kill, oom-kill) |
| 128 - allow reboot/poweroff |
| 256 - allow nicing of all real-time tasks |
| |
| This file is only present if the |
| .B CONFIG_MAGIC_SYSRQ |
| kernel configuration option is enabled. |
| For further details see the Linux kernel source file |
| .IR Documentation/sysrq.txt . |
| .TP |
| .I /proc/sys/kernel/version |
| This file contains a string like: |
| |
| #5 Wed Feb 25 21:49:24 MET 1998 |
| |
| The "#5" means that |
| this is the fifth kernel built from this source base and the |
| date behind it indicates the time the kernel was built. |
| .TP |
| .IR /proc/sys/kernel/threads-max " (since Linux 2.3.11)" |
| This file specifies the system-wide limit on the number of |
| threads (tasks) that can be created on the system. |
| .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/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 file system |
| (NFS). |
| On some systems, it is not present. |
| .TP |
| .I /proc/sys/vm |
| This directory contains files for memory management tuning, buffer and |
| cache management. |
| .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. |
| |
| To free pagecache, use |
| .IR "echo 1 > /proc/sys/vm/drop_caches" ; |
| to free dentries and inodes, use |
| .IR "echo 2 > /proc/sys/vm/drop_caches" ; |
| to free pagecache, dentries and inodes, use |
| .IR "echo 3 > /proc/sys/vm/drop_caches" . |
| |
| Because this is a nondestructive operation and dirty objects |
| are not freeable, the |
| user should run |
| .BR sync (8) |
| first. |
| .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. |
| |
| 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 this is not supported for a few types of pages, like kernel internally |
| allocated data or the swap cache, but works for the majority of user pages. |
| .IP 0: 4 |
| Only unmap the corrupted page from all processes and only kill a process |
| who tries to access it. |
| .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. |
| |
| This feature is only active on architectures/platforms with advanced machine |
| check handling and depends on the hardware capabilities. |
| |
| Applications can override the |
| .I memory_failure_early_kill |
| setting individually with the |
| .BR prctl (2) |
| .B PR_MCE_KILL |
| operation. |
| .IP |
| Only present 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 |
| Only present 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. |
| |
| 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. |
| |
| If this is set to nonzero, this information is shown whenever the |
| OOM-killer actually kills a memory-hogging task. |
| |
| 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. |
| |
| 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. |
| |
| 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. |
| |
| 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 . |
| |
| The default value is 0. |
| .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". |
| Under Linux 2.4 any nonzero value implies mode 1. |
| In mode 2 (available since Linux 2.6), the total virtual address space |
| on the system is limited to (SS + RAM*(r/100)), |
| where SS is the size of the swap space, and RAM |
| is the size of the physical memory, and r is the contents of the file |
| .IR /proc/sys/vm/overcommit_ratio . |
| .TP |
| .I /proc/sys/vm/overcommit_ratio |
| 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. |
| |
| 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. |
| |
| 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. |
| |
| If this file is set to the value 2, |
| the kernel always panics when an out-of-memory condition occurs. |
| |
| 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/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 only writable by |
| .IR root . |
| For further details see the Linux kernel source file |
| .IR Documentation/sysrq.txt . |
| .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 svipc (7) |
| provides further background on the information shown by these files. |
| .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: the uptime of the system (seconds), |
| and the amount of time spent in idle process (seconds). |
| .TP |
| .I /proc/version |
| This string identifies the kernel version that is currently running. |
| It includes the contents of |
| .IR /proc/sys/kernel/ostype , |
| .I /proc/sys/kernel/osrelease |
| and |
| .IR /proc/sys/kernel/version . |
| For example: |
| .nf |
| .in -2 |
| .ft CW |
| 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. |
| .TP |
| .IR /proc/zoneinfo " (since Linux 2.6.13)" |
| This file display information about memory zones. |
| This is useful for analyzing virtual memory behavior. |
| .\" FIXME more should be said about /proc/zoneinfo |
| .SH NOTES |
| Many strings (i.e., the environment and command line) are in |
| the internal format, with subfields terminated by null bytes (\(aq\\0\(aq), |
| so you |
| may find that things are more readable if you use \fIod \-c\fP or \fItr |
| "\\000" "\\n"\fP to read them. |
| Alternatively, \fIecho \`cat <file>\`\fP works well. |
| |
| 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 ps (1), |
| .BR tr (1), |
| .BR uptime (1), |
| .BR chroot (2), |
| .BR mmap (2), |
| .BR readlink (2), |
| .BR syslog (2), |
| .BR slabinfo (5), |
| .BR hier (7), |
| .BR time (7), |
| .BR arp (8), |
| .BR hdparm (8), |
| .BR ifconfig (8), |
| .BR init (8), |
| .BR lsmod (8), |
| .BR lspci (8), |
| .BR mount (8), |
| .BR netstat (8), |
| .BR procinfo (8), |
| .BR route (8) |
| |
| The Linux kernel source files: |
| .IR Documentation/filesystems/proc.txt |
| and |
| .IR Documentation/sysctl/vm.txt . |