| .\" Copyright (C) 1994, 1995 by Daniel Quinlan (quinlan@yggdrasil.com) |
| .\" and Copyright (C) 2002-2008,2017 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> |
| .\" |
| .\" %%%LICENSE_START(GPLv2+_DOC_FULL) |
| .\" 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, see |
| .\" <http://www.gnu.org/licenses/>. |
| .\" %%%LICENSE_END |
| .\" |
| .\" 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 cross check against Documentation/filesystems/proc.txt |
| .\" to see what information could be imported from that file |
| .\" into this file. |
| .\" |
| .TH PROC 5 2020-08-13 "Linux" "Linux Programmer's Manual" |
| .SH NAME |
| proc \- process information pseudo-filesystem |
| .SH DESCRIPTION |
| The |
| .B proc |
| filesystem is a pseudo-filesystem which provides an interface to |
| kernel data structures. |
| It is commonly mounted at |
| .IR /proc . |
| Typically, it is mounted automatically by the system, |
| but it can also be mounted manually using a command such as: |
| .PP |
| .in +4n |
| .EX |
| mount \-t proc proc /proc |
| .EE |
| .in |
| .PP |
| Most of the files in the |
| .B proc |
| filesystem are read-only, |
| but some files are writable, allowing kernel variables to be changed. |
| .\" |
| .SS Mount options |
| The |
| .B proc |
| filesystem supports the following mount options: |
| .TP |
| .BR hidepid "=\fIn\fP (since Linux 3.3)" |
| .\" commit 0499680a42141d86417a8fbaa8c8db806bea1201 |
| This option controls who can access the information in |
| .IR /proc/[pid] |
| directories. |
| The argument, |
| .IR n , |
| is one of the following values: |
| .RS |
| .TP 4 |
| 0 |
| Everybody may access all |
| .IR /proc/[pid] |
| directories. |
| This is the traditional behavior, |
| and the default if this mount option is not specified. |
| .TP |
| 1 |
| Users may not access files and subdirectories inside any |
| .IR /proc/[pid] |
| directories but their own (the |
| .IR /proc/[pid] |
| directories themselves remain visible). |
| Sensitive files such as |
| .IR /proc/[pid]/cmdline |
| and |
| .IR /proc/[pid]/status |
| are now protected against other users. |
| This makes it impossible to learn whether any user is running a |
| specific program |
| (so long as the program doesn't otherwise reveal itself by its behavior). |
| .\" As an additional bonus, since |
| .\" .IR /proc/[pid]/cmdline |
| .\" is inaccessible for other users, |
| .\" poorly written programs passing sensitive information via |
| .\" program arguments are now protected against local eavesdroppers. |
| .TP |
| 2 |
| As for mode 1, but in addition the |
| .IR /proc/[pid] |
| directories belonging to other users become invisible. |
| This means that |
| .IR /proc/[pid] |
| entries can no longer be used to discover the PIDs on the system. |
| This doesn't hide the fact that a process with a specific PID value exists |
| (it can be learned by other means, for example, by "kill \-0 $PID"), |
| but it hides a process's UID and GID, |
| which could otherwise be learned by employing |
| .BR stat (2) |
| on a |
| .IR /proc/[pid] |
| directory. |
| This greatly complicates an attacker's task of gathering |
| information about running processes (e.g., discovering whether |
| some daemon is running with elevated privileges, |
| whether another user is running some sensitive program, |
| whether other users are running any program at all, and so on). |
| .RE |
| .TP |
| .BR gid "=\fIgid\fP (since Linux 3.3)" |
| .\" commit 0499680a42141d86417a8fbaa8c8db806bea1201 |
| Specifies the ID of a group whose members are authorized to |
| learn process information otherwise prohibited by |
| .BR hidepid |
| (i.e., users in this group behave as though |
| .I /proc |
| was mounted with |
| .IR hidepid=0 ). |
| This group should be used instead of approaches such as putting |
| nonroot users into the |
| .BR sudoers (5) |
| file. |
| .\" |
| .SS Overview |
| Underneath |
| .IR /proc , |
| there are the following general groups of files and subdirectories: |
| .TP |
| .IR /proc/[pid] " subdirectories" |
| Each one of these subdirectories contains files and subdirectories |
| exposing information about the process with the corresponding process ID. |
| .IP |
| Underneath each of the |
| .I /proc/[pid] |
| directories, a |
| .I task |
| subdirectory contains subdirectories of the form |
| .IR task/[tid] , |
| which contain corresponding information about each of the threads |
| in the process, where |
| .I tid |
| is the kernel thread ID of the thread. |
| .IP |
| The |
| .I /proc/[pid] |
| subdirectories are visible when iterating through |
| .I /proc |
| with |
| .BR getdents (2) |
| (and thus are visible when one uses |
| .BR ls (1) |
| to view the contents of |
| .IR /proc ). |
| .TP |
| .IR /proc/[tid] " subdirectories" |
| Each one of these subdirectories contains files and subdirectories |
| exposing information about the thread with the corresponding thread ID. |
| The contents of these directories are the same as the corresponding |
| .IR /proc/[pid]/task/[tid] |
| directories. |
| .IP |
| The |
| .I /proc/[tid] |
| subdirectories are |
| .I not |
| visible when iterating through |
| .I /proc |
| with |
| .BR getdents (2) |
| (and thus are |
| .I not |
| visible when one uses |
| .BR ls (1) |
| to view the contents of |
| .IR /proc ). |
| .TP |
| .I /proc/self |
| When a process accesses this magic symbolic link, |
| it resolves to the process's own |
| .I /proc/[pid] |
| directory. |
| .TP |
| .I /proc/thread\-self |
| When a thread accesses this magic symbolic link, |
| it resolves to the process's own |
| .I /proc/self/task/[tid] |
| directory. |
| .TP |
| .I /proc/[a\-z]* |
| Various other files and subdirectories under |
| .I /proc |
| expose system-wide information. |
| .PP |
| All of the above are described in more detail below. |
| .\" |
| .SS Files and directories |
| The following list provides details of many of the files and directories |
| under the |
| .I /proc |
| hierarchy. |
| .TP |
| .I /proc/[pid] |
| There is a numerical subdirectory for each running process; the |
| subdirectory is named by the process ID. |
| Each |
| .I /proc/[pid] |
| subdirectory contains the pseudo-files and directories described below. |
| .IP |
| The files inside each |
| .I /proc/[pid] |
| directory are normally owned by the effective user and |
| effective group ID of the process. |
| However, as a security measure, the ownership is made |
| .IR root:root |
| if the process's "dumpable" attribute is set to a value other than 1. |
| .IP |
| Before Linux 4.11, |
| .\" commit 68eb94f16227336a5773b83ecfa8290f1d6b78ce |
| .IR root:root |
| meant the "global" root user ID and group ID |
| (i.e., UID 0 and GID 0 in the initial user namespace). |
| Since Linux 4.11, |
| if the process is in a noninitial user namespace that has a |
| valid mapping for user (group) ID 0 inside the namespace, then |
| the user (group) ownership of the files under |
| .I /proc/[pid] |
| is instead made the same as the root user (group) ID of the namespace. |
| This means that inside a container, |
| things work as expected for the container "root" user. |
| .IP |
| The process's "dumpable" attribute may change for the following reasons: |
| .RS |
| .IP * 3 |
| The attribute was explicitly set via the |
| .BR prctl (2) |
| .B PR_SET_DUMPABLE |
| operation. |
| .IP * |
| The attribute was reset to the value in the file |
| .IR /proc/sys/fs/suid_dumpable |
| (described below), for the reasons described in |
| .BR prctl (2). |
| .RE |
| .IP |
| Resetting the "dumpable" attribute to 1 reverts the ownership of the |
| .IR /proc/[pid]/* |
| files to the process's effective UID and GID. |
| Note, however, that if the effective UID or GID is subsequently modified, |
| then the "dumpable" attribute may be reset, as described in |
| .BR prctl (2). |
| Therefore, it may be desirable to reset the "dumpable" attribute |
| .I after |
| making any desired changes to the process's effective UID or GID. |
| .TP |
| .I /proc/[pid]/attr |
| .\" https://lwn.net/Articles/28222/ |
| .\" From: Stephen Smalley <sds@epoch.ncsc.mil> |
| .\" To: LKML and others |
| .\" Subject: [RFC][PATCH] Process Attribute API for Security Modules |
| .\" Date: 08 Apr 2003 16:17:52 -0400 |
| .\" |
| .\" http://www.nsa.gov/research/_files/selinux/papers/module/x362.shtml |
| .\" |
| The files in this directory provide an API for security modules. |
| The contents of this directory are files that can be read and written |
| in order to set security-related attributes. |
| This directory was added to support SELinux, |
| but the intention was that the API be general enough to support |
| other security modules. |
| For the purpose of explanation, |
| examples of how SELinux uses these files are provided below. |
| .IP |
| This directory is present only if the kernel was configured with |
| .BR CONFIG_SECURITY . |
| .TP |
| .IR /proc/[pid]/attr/current " (since Linux 2.6.0)" |
| The contents of this file represent the current |
| security attributes of the process. |
| .IP |
| In SELinux, this file is used to get the security context of a process. |
| Prior to Linux 2.6.11, this file could not be used to set the security |
| context (a write was always denied), since SELinux limited process security |
| transitions to |
| .BR execve (2) |
| (see the description of |
| .IR /proc/[pid]/attr/exec , |
| below). |
| Since Linux 2.6.11, SELinux lifted this restriction and began supporting |
| "set" operations via writes to this node if authorized by policy, |
| although use of this operation is only suitable for applications that are |
| trusted to maintain any desired separation between the old and new security |
| contexts. |
| .IP |
| Prior to Linux 2.6.28, SELinux did not allow threads within a |
| multithreaded process to set their security context via this node |
| as it would yield an inconsistency among the security contexts of the |
| threads sharing the same memory space. |
| Since Linux 2.6.28, SELinux lifted |
| this restriction and began supporting "set" operations for threads within |
| a multithreaded process if the new security context is bounded by the old |
| security context, where the bounded relation is defined in policy and |
| guarantees that the new security context has a subset of the permissions |
| of the old security context. |
| .IP |
| Other security modules may choose to support "set" operations via |
| writes to this node. |
| .TP |
| .IR /proc/[pid]/attr/exec " (since Linux 2.6.0)" |
| This file represents the attributes to assign to the |
| process upon a subsequent |
| .BR execve (2). |
| .IP |
| In SELinux, |
| this is needed to support role/domain transitions, and |
| .BR execve (2) |
| is the preferred point to make such transitions because it offers better |
| control over the initialization of the process in the new security label |
| and the inheritance of state. |
| In SELinux, this attribute is reset on |
| .BR execve (2) |
| so that the new program reverts to the default behavior for any |
| .BR execve (2) |
| calls that it may make. |
| In SELinux, a process can set |
| only its own |
| .I /proc/[pid]/attr/exec |
| attribute. |
| .TP |
| .IR /proc/[pid]/attr/fscreate " (since Linux 2.6.0)" |
| This file represents the attributes to assign to files |
| created by subsequent calls to |
| .BR open (2), |
| .BR mkdir (2), |
| .BR symlink (2), |
| and |
| .BR mknod (2) |
| .IP |
| SELinux employs this file to support creation of a file |
| (using the aforementioned system calls) |
| in a secure state, |
| so that there is no risk of inappropriate access being obtained |
| between the time of creation and the time that attributes are set. |
| In SELinux, this attribute is reset on |
| .BR execve (2), |
| so that the new program reverts to the default behavior for |
| any file creation calls it may make, but the attribute will persist |
| across multiple file creation calls within a program unless it is |
| explicitly reset. |
| In SELinux, a process can set only its own |
| .IR /proc/[pid]/attr/fscreate |
| attribute. |
| .TP |
| .IR /proc/[pid]/attr/keycreate " (since Linux 2.6.18)" |
| .\" commit 4eb582cf1fbd7b9e5f466e3718a59c957e75254e |
| If a process writes a security context into this file, |
| all subsequently created keys |
| .RB ( add_key (2)) |
| will be labeled with this context. |
| For further information, see the kernel source file |
| .I Documentation/security/keys/core.rst |
| (or file |
| .\" commit b68101a1e8f0263dbc7b8375d2a7c57c6216fb76 |
| .I Documentation/security/keys.txt |
| on Linux between 3.0 and 4.13, or |
| .\" commit d410fa4ef99112386de5f218dd7df7b4fca910b4 |
| .I Documentation/keys.txt |
| before Linux 3.0). |
| .TP |
| .IR /proc/[pid]/attr/prev " (since Linux 2.6.0)" |
| This file contains the security context of the process before the last |
| .BR execve (2); |
| that is, the previous value of |
| .IR /proc/[pid]/attr/current . |
| .TP |
| .IR /proc/[pid]/attr/socketcreate " (since Linux 2.6.18)" |
| .\" commit 42c3e03ef6b298813557cdb997bd6db619cd65a2 |
| If a process writes a security context into this file, |
| all subsequently created sockets will be labeled with this context. |
| .TP |
| .IR /proc/[pid]/autogroup " (since Linux 2.6.38)" |
| .\" commit 5091faa449ee0b7d73bc296a93bca9540fc51d0a |
| See |
| .BR sched (7). |
| .TP |
| .IR /proc/[pid]/auxv " (since 2.6.0)" |
| .\" Precisely: Linux 2.6.0-test7 |
| This contains the contents of the ELF interpreter information passed |
| to the process at exec time. |
| The format is one \fIunsigned long\fP ID |
| plus one \fIunsigned long\fP value for each entry. |
| The last entry contains two zeros. |
| See also |
| .BR getauxval (3). |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[pid]/cgroup " (since Linux 2.6.24)" |
| See |
| .BR cgroups (7). |
| .TP |
| .IR /proc/[pid]/clear_refs " (since Linux 2.6.22)" |
| .\" commit b813e931b4c8235bb42e301096ea97dbdee3e8fe (2.6.22) |
| .\" commit 398499d5f3613c47f2143b8c54a04efb5d7a6da9 (2.6.32) |
| .\" commit 040fa02077de01c7e08fa75be6125e4ca5636011 (3.11) |
| .\" |
| .\" "Clears page referenced bits shown in smaps output" |
| .\" write-only, writable only by the owner of the process |
| .IP |
| This is a write-only file, writable only by owner of the process. |
| .IP |
| The following values may be written to the file: |
| .RS |
| .TP |
| 1 (since Linux 2.6.22) |
| .\" Internally: CLEAR_REFS_ALL |
| Reset the PG_Referenced and ACCESSED/YOUNG |
| bits for all the pages associated with the process. |
| (Before kernel 2.6.32, writing any nonzero value to this file |
| had this effect.) |
| .TP |
| 2 (since Linux 2.6.32) |
| .\" Internally: CLEAR_REFS_ANON |
| Reset the PG_Referenced and ACCESSED/YOUNG |
| bits for all anonymous pages associated with the process. |
| .TP |
| 3 (since Linux 2.6.32) |
| .\" Internally: CLEAR_REFS_MAPPED |
| Reset the PG_Referenced and ACCESSED/YOUNG |
| bits for all file-mapped pages associated with the process. |
| .RE |
| .IP |
| Clearing the PG_Referenced and ACCESSED/YOUNG bits provides a method |
| to measure approximately how much memory a process is using. |
| One first inspects the values in the "Referenced" fields |
| for the VMAs shown in |
| .IR /proc/[pid]/smaps |
| to get an idea of the memory footprint of the |
| process. |
| One then clears the PG_Referenced and ACCESSED/YOUNG bits |
| and, after some measured time interval, |
| once again inspects the values in the "Referenced" fields |
| to get an idea of the change in memory footprint of the |
| process during the measured interval. |
| If one is interested only in inspecting the selected mapping types, |
| then the value 2 or 3 can be used instead of 1. |
| .IP |
| Further values can be written to affect different properties: |
| .RS |
| .TP |
| 4 (since Linux 3.11) |
| Clear the soft-dirty bit for all the pages associated with the process. |
| .\" Internally: CLEAR_REFS_SOFT_DIRTY |
| This is used (in conjunction with |
| .IR /proc/[pid]/pagemap ) |
| by the check-point restore system to discover which pages of a process |
| have been dirtied since the file |
| .IR /proc/[pid]/clear_refs |
| was written to. |
| .TP |
| 5 (since Linux 4.0) |
| .\" Internally: CLEAR_REFS_MM_HIWATER_RSS |
| Reset the peak resident set size ("high water mark") to the process's |
| current resident set size value. |
| .RE |
| .IP |
| Writing any value to |
| .IR /proc/[pid]/clear_refs |
| other than those listed above has no effect. |
| .IP |
| The |
| .IR /proc/[pid]/clear_refs |
| file is present only if the |
| .B CONFIG_PROC_PAGE_MONITOR |
| kernel configuration option is enabled. |
| .TP |
| .I /proc/[pid]/cmdline |
| This read-only file holds the complete command line for the process, |
| unless the process is a zombie. |
| .\" In 2.3.26, this also used to be true if the process was swapped out. |
| In the latter case, there is nothing in this file: |
| that is, a read on this file will return 0 characters. |
| The command-line arguments appear in this file as a set of |
| strings separated by null bytes (\(aq\e0\(aq), |
| with a further null byte after the last string. |
| .IP |
| If, after an |
| .BR execve (2), |
| the process modifies its |
| .I argv |
| strings, those changes will show up here. |
| This is not the same thing as modifying the |
| .I argv |
| array. |
| .IP |
| Furthermore, a process may change the memory location that this file refers via |
| .BR prctl (2) |
| operations such as |
| .BR PR_SET_MM_ARG_START . |
| .IP |
| Think of this file as the command line that the process wants you to see. |
| .TP |
| .IR /proc/[pid]/comm " (since Linux 2.6.33)" |
| .\" commit 4614a696bd1c3a9af3a08f0e5874830a85b889d4 |
| This file exposes the process's |
| .I comm |
| value\(emthat is, the command name associated with the process. |
| Different threads in the same process may have different |
| .I comm |
| values, accessible via |
| .IR /proc/[pid]/task/[tid]/comm . |
| A thread may modify its |
| .I comm |
| value, or that of any of other thread in the same thread group (see |
| the discussion of |
| .B CLONE_THREAD |
| in |
| .BR clone (2)), |
| by writing to the file |
| .IR /proc/self/task/[tid]/comm . |
| Strings longer than |
| .B TASK_COMM_LEN |
| (16) characters (including the terminating null byte) are silently truncated. |
| .IP |
| This file provides a superset of the |
| .BR prctl (2) |
| .B PR_SET_NAME |
| and |
| .B PR_GET_NAME |
| operations, and is employed by |
| .BR pthread_setname_np (3) |
| when used to rename threads other than the caller. |
| The value in this file is used for the |
| .I %e |
| specifier in |
| .IR /proc/sys/kernel/core_pattern ; |
| see |
| .BR core (5). |
| .TP |
| .IR /proc/[pid]/coredump_filter " (since Linux 2.6.23)" |
| See |
| .BR core (5). |
| .TP |
| .IR /proc/[pid]/cpuset " (since Linux 2.6.12)" |
| .\" and/proc/[pid]/task/[tid]/cpuset |
| See |
| .BR cpuset (7). |
| .TP |
| .I /proc/[pid]/cwd |
| This is a symbolic link to the current working directory of the process. |
| To find out the current working directory of process 20, |
| for instance, you can do this: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " cd /proc/20/cwd; pwd \-P" |
| .EE |
| .in |
| .IP |
| .\" The following was still true as at kernel 2.6.13 |
| In a multithreaded process, the contents of this symbolic link |
| are not available if the main thread has already terminated |
| (typically by calling |
| .BR pthread_exit (3)). |
| .IP |
| Permission to dereference or read |
| .RB ( readlink (2)) |
| this symbolic link is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .I /proc/[pid]/environ |
| This file contains the initial environment that was set |
| when the currently executing program was started via |
| .BR execve (2). |
| The entries are separated by null bytes (\(aq\e0\(aq), |
| and there may be a null byte at the end. |
| Thus, to print out the environment of process 1, you would do: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " cat /proc/1/environ | tr \(aq\e000\(aq \(aq\en\(aq" |
| .EE |
| .in |
| .IP |
| If, after an |
| .BR execve (2), |
| the process modifies its environment |
| (e.g., by calling functions such as |
| .BR putenv (3) |
| or modifying the |
| .BR environ (7) |
| variable directly), |
| this file will |
| .I not |
| reflect those changes. |
| .IP |
| Furthermore, a process may change the memory location that this file refers via |
| .BR prctl (2) |
| operations such as |
| .BR PR_SET_MM_ENV_START . |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .I /proc/[pid]/exe |
| Under Linux 2.2 and later, this file is a symbolic link |
| containing the actual pathname of the executed command. |
| This symbolic link can be dereferenced normally; attempting to open |
| it will open the executable. |
| You can even type |
| .I /proc/[pid]/exe |
| to run another copy of the same executable that is being run by |
| process [pid]. |
| If the pathname has been unlinked, the symbolic link will contain the |
| string \(aq(deleted)\(aq appended to the original pathname. |
| .\" The following was still true as at kernel 2.6.13 |
| In a multithreaded process, the contents of this symbolic link |
| are not available if the main thread has already terminated |
| (typically by calling |
| .BR pthread_exit (3)). |
| .IP |
| Permission to dereference or read |
| .RB ( readlink (2)) |
| this symbolic link is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .IP |
| Under Linux 2.0 and earlier, |
| .I /proc/[pid]/exe |
| is a pointer to the binary which was executed, |
| and appears as a symbolic link. |
| A |
| .BR readlink (2) |
| call on this file under Linux 2.0 returns a string in the format: |
| .IP |
| [device]:inode |
| .IP |
| For example, [0301]:1502 would be inode 1502 on device major 03 (IDE, |
| MFM, etc. drives) minor 01 (first partition on the first drive). |
| .IP |
| .BR find (1) |
| with the |
| .I \-inum |
| option can be used to locate the file. |
| .TP |
| .I /proc/[pid]/fd/ |
| This is a subdirectory containing one entry for each file which the |
| process has open, named by its file descriptor, and which is a |
| symbolic link to the actual file. |
| Thus, 0 is standard input, 1 standard output, 2 standard error, and so on. |
| .IP |
| For file descriptors for pipes and sockets, |
| the entries will be symbolic links whose content is the |
| file type with the inode. |
| A |
| .BR readlink (2) |
| call on this file returns a string in the format: |
| .IP |
| type:[inode] |
| .IP |
| For example, |
| .I socket:[2248868] |
| will be a socket and its inode is 2248868. |
| For sockets, that inode can be used to find more information |
| in one of the files under |
| .IR /proc/net/ . |
| .IP |
| For file descriptors that have no corresponding inode |
| (e.g., file descriptors produced by |
| .BR bpf (2), |
| .BR epoll_create (2), |
| .BR eventfd (2), |
| .BR inotify_init (2), |
| .BR perf_event_open (2), |
| .BR signalfd (2), |
| .BR timerfd_create (2), |
| and |
| .BR userfaultfd (2)), |
| the entry will be a symbolic link with contents of the form |
| .IP |
| anon_inode:<file-type> |
| .IP |
| In many cases (but not all), the |
| .I file-type |
| is surrounded by square brackets. |
| .IP |
| For example, an epoll file descriptor will have a symbolic link |
| whose content is the string |
| .IR "anon_inode:[eventpoll]" . |
| .IP |
| .\"The following was still true as at kernel 2.6.13 |
| In a multithreaded process, the contents of this directory |
| are not available if the main thread has already terminated |
| (typically by calling |
| .BR pthread_exit (3)). |
| .IP |
| Programs that take a filename as a command-line argument, |
| but don't take input from standard input if no argument is supplied, |
| and programs that write to a file named as a command-line argument, |
| but don't send their output to standard output |
| if no argument is supplied, can nevertheless be made to use |
| standard input or standard output by using |
| .IR /proc/[pid]/fd |
| files as command-line arguments. |
| For example, assuming that |
| .I \-i |
| is the flag designating an input file and |
| .I \-o |
| is the flag designating an output file: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " foobar \-i /proc/self/fd/0 \-o /proc/self/fd/1 ..." |
| .EE |
| .in |
| .IP |
| and you have a working filter. |
| .\" The following is not true in my tests (MTK): |
| .\" Note that this will not work for |
| .\" programs that seek on their files, as the files in the fd directory |
| .\" are not seekable. |
| .IP |
| .I /proc/self/fd/N |
| is approximately the same as |
| .I /dev/fd/N |
| in some UNIX and UNIX-like systems. |
| Most Linux MAKEDEV scripts symbolically link |
| .I /dev/fd |
| to |
| .IR /proc/self/fd , |
| in fact. |
| .IP |
| Most systems provide symbolic links |
| .IR /dev/stdin , |
| .IR /dev/stdout , |
| and |
| .IR /dev/stderr , |
| which respectively link to the files |
| .IR 0 , |
| .IR 1 , |
| and |
| .IR 2 |
| in |
| .IR /proc/self/fd . |
| Thus the example command above could be written as: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..." |
| .EE |
| .in |
| .IP |
| Permission to dereference or read |
| .RB ( readlink (2)) |
| the symbolic links in this directory is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .IP |
| Note that for file descriptors referring to inodes (pipes and sockets, see above), |
| those inodes still have permission bits and ownership information |
| distinct from those of the |
| .I /proc/[pid]/fd |
| entry, |
| and that the owner may differ from the user and group IDs of the process. |
| An unprivileged process may lack permissions to open them, as in this example: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " echo test | sudo \-u nobody cat" |
| test |
| .RB "$" " echo test | sudo \-u nobody cat /proc/self/fd/0" |
| cat: /proc/self/fd/0: Permission denied |
| .EE |
| .in |
| .IP |
| File descriptor 0 refers to the pipe created by the shell |
| and owned by that shell's user, which is not |
| .IR nobody , |
| so |
| .B cat |
| does not have permission to create a new file descriptor to read from that inode, |
| even though it can still read from its existing file descriptor 0. |
| .TP |
| .IR /proc/[pid]/fdinfo/ " (since Linux 2.6.22)" |
| This is a subdirectory containing one entry for each file which the |
| process has open, named by its file descriptor. |
| The files in this directory are readable only by the owner of the process. |
| The contents of each file can be read to obtain information |
| about the corresponding file descriptor. |
| The content depends on the type of file referred to by the |
| corresponding file descriptor. |
| .IP |
| For regular files and directories, we see something like: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " cat /proc/12015/fdinfo/4" |
| pos: 1000 |
| flags: 01002002 |
| mnt_id: 21 |
| .EE |
| .in |
| .IP |
| The fields are as follows: |
| .RS |
| .TP |
| .I pos |
| This is a decimal number showing the file offset. |
| .TP |
| .I flags |
| This is an octal number that displays the |
| file access mode and file status flags (see |
| .BR open (2)). |
| If the close-on-exec file descriptor flag is set, then |
| .I flags |
| will also include the value |
| .BR O_CLOEXEC . |
| .IP |
| Before Linux 3.1, |
| .\" commit 1117f72ea0217ba0cc19f05adbbd8b9a397f5ab7 |
| this field incorrectly displayed the setting of |
| .B O_CLOEXEC |
| at the time the file was opened, |
| rather than the current setting of the close-on-exec flag. |
| .TP |
| .I |
| .I mnt_id |
| This field, present since Linux 3.15, |
| .\" commit 49d063cb353265c3af701bab215ac438ca7df36d |
| is the ID of the mount point containing this file. |
| See the description of |
| .IR /proc/[pid]/mountinfo . |
| .RE |
| .IP |
| For eventfd file descriptors (see |
| .BR eventfd (2)), |
| we see (since Linux 3.8) |
| .\" commit cbac5542d48127b546a23d816380a7926eee1c25 |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 02 |
| mnt_id: 10 |
| eventfd\-count: 40 |
| .EE |
| .in |
| .IP |
| .I eventfd\-count |
| is the current value of the eventfd counter, in hexadecimal. |
| .IP |
| For epoll file descriptors (see |
| .BR epoll (7)), |
| we see (since Linux 3.8) |
| .\" commit 138d22b58696c506799f8de759804083ff9effae |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 02 |
| mnt_id: 10 |
| tfd: 9 events: 19 data: 74253d2500000009 |
| tfd: 7 events: 19 data: 74253d2500000007 |
| .EE |
| .in |
| .IP |
| Each of the lines beginning |
| .I tfd |
| describes one of the file descriptors being monitored via |
| the epoll file descriptor (see |
| .BR epoll_ctl (2) |
| for some details). |
| The |
| .IR tfd |
| field is the number of the file descriptor. |
| The |
| .I events |
| field is a hexadecimal mask of the events being monitored for this file |
| descriptor. |
| The |
| .I data |
| field is the data value associated with this file descriptor. |
| .IP |
| For signalfd file descriptors (see |
| .BR signalfd (2)), |
| we see (since Linux 3.8) |
| .\" commit 138d22b58696c506799f8de759804083ff9effae |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 02 |
| mnt_id: 10 |
| sigmask: 0000000000000006 |
| .EE |
| .in |
| .IP |
| .I sigmask |
| is the hexadecimal mask of signals that are accepted via this |
| signalfd file descriptor. |
| (In this example, bits 2 and 3 are set, corresponding to the signals |
| .B SIGINT |
| and |
| .BR SIGQUIT ; |
| see |
| .BR signal (7).) |
| .IP |
| For inotify file descriptors (see |
| .BR inotify (7)), |
| we see (since Linux 3.8) |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 00 |
| mnt_id: 11 |
| inotify wd:2 ino:7ef82a sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:2af87e00220ffd73 |
| inotify wd:1 ino:192627 sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:27261900802dfd73 |
| .EE |
| .in |
| .IP |
| Each of the lines beginning with "inotify" displays information about |
| one file or directory that is being monitored. |
| The fields in this line are as follows: |
| .RS |
| .TP |
| .I wd |
| A watch descriptor number (in decimal). |
| .TP |
| .I ino |
| The inode number of the target file (in hexadecimal). |
| .TP |
| .I sdev |
| The ID of the device where the target file resides (in hexadecimal). |
| .TP |
| .I mask |
| The mask of events being monitored for the target file (in hexadecimal). |
| .RE |
| .IP |
| If the kernel was built with exportfs support, the path to the target |
| file is exposed as a file handle, via three hexadecimal fields: |
| .IR fhandle\-bytes , |
| .IR fhandle\-type , |
| and |
| .IR f_handle . |
| .IP |
| For fanotify file descriptors (see |
| .BR fanotify (7)), |
| we see (since Linux 3.8) |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 02 |
| mnt_id: 11 |
| fanotify flags:0 event\-flags:88002 |
| fanotify ino:19264f sdev:800001 mflags:0 mask:1 ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:4f261900a82dfd73 |
| .EE |
| .in |
| .IP |
| The fourth line displays information defined when the fanotify group |
| was created via |
| .BR fanotify_init (2): |
| .RS |
| .TP |
| .I flags |
| The |
| .I flags |
| argument given to |
| .BR fanotify_init (2) |
| (expressed in hexadecimal). |
| .TP |
| .I event\-flags |
| The |
| .I event_f_flags |
| argument given to |
| .BR fanotify_init (2) |
| (expressed in hexadecimal). |
| .RE |
| .IP |
| Each additional line shown in the file contains information |
| about one of the marks in the fanotify group. |
| Most of these fields are as for inotify, except: |
| .RS |
| .TP |
| .I mflags |
| The flags associated with the mark |
| (expressed in hexadecimal). |
| .TP |
| .I mask |
| The events mask for this mark |
| (expressed in hexadecimal). |
| .TP |
| .I ignored_mask |
| The mask of events that are ignored for this mark |
| (expressed in hexadecimal). |
| .RE |
| .IP |
| For details on these fields, see |
| .BR fanotify_mark (2). |
| .IP |
| For timerfd file descriptors (see |
| .BR timerfd (2)), |
| we see (since Linux 3.17) |
| .\" commit af9c4957cf212ad9cf0bee34c95cb11de5426e85 |
| the following fields: |
| .IP |
| .in +4n |
| .EX |
| pos: 0 |
| flags: 02004002 |
| mnt_id: 13 |
| clockid: 0 |
| ticks: 0 |
| settime flags: 03 |
| it_value: (7695568592, 640020877) |
| it_interval: (0, 0) |
| .EE |
| .in |
| .RS |
| .TP |
| .I clockid |
| This is the numeric value of the clock ID |
| (corresponding to one of the |
| .B CLOCK_* |
| constants defined via |
| .IR <time.h> ) |
| that is used to mark the progress of the timer (in this example, 0 is |
| .BR CLOCK_REALTIME ). |
| .TP |
| .I ticks |
| This is the number of timer expirations that have occurred, |
| (i.e., the value that |
| .BR read (2) |
| on it would return). |
| .TP |
| .I settime flags |
| This field lists the flags with which the timerfd was last armed (see |
| .BR timerfd_settime (2)), |
| in octal |
| (in this example, both |
| .B TFD_TIMER_ABSTIME |
| and |
| .B TFD_TIMER_CANCEL_ON_SET |
| are set). |
| .TP |
| .I it_value |
| This field contains the amount of time until the timer will next expire, |
| expressed in seconds and nanoseconds. |
| This is always expressed as a relative value, |
| regardless of whether the timer was created using the |
| .B TFD_TIMER_ABSTIME |
| flag. |
| .TP |
| .I it_interval |
| This field contains the interval of the timer, |
| in seconds and nanoseconds. |
| (The |
| .I it_value |
| and |
| .I it_interval |
| fields contain the values that |
| .BR timerfd_gettime (2) |
| on this file descriptor would return.) |
| .RE |
| .TP |
| .IR /proc/[pid]/gid_map " (since Linux 3.5)" |
| See |
| .BR user_namespaces (7). |
| .TP |
| .IR /proc/[pid]/io " (since kernel 2.6.20)" |
| .\" commit 7c3ab7381e79dfc7db14a67c6f4f3285664e1ec2 |
| This file contains I/O statistics for the process, for example: |
| .IP |
| .in +4n |
| .EX |
| .RB "#" " cat /proc/3828/io" |
| rchar: 323934931 |
| wchar: 323929600 |
| syscr: 632687 |
| syscw: 632675 |
| read_bytes: 0 |
| write_bytes: 323932160 |
| cancelled_write_bytes: 0 |
| .EE |
| .in |
| .IP |
| The fields are as follows: |
| .RS |
| .TP |
| .IR rchar ": characters read" |
| The number of bytes which this task has caused to be read from storage. |
| This is simply the sum of bytes which this process passed to |
| .BR read (2) |
| and similar system calls. |
| It includes things such as terminal I/O and |
| is unaffected by whether or not actual |
| physical disk I/O was required (the read might have been satisfied from |
| pagecache). |
| .TP |
| .IR wchar ": characters written" |
| The number of bytes which this task has caused, or shall cause to be written |
| to disk. |
| Similar caveats apply here as with |
| .IR rchar . |
| .TP |
| .IR syscr ": read syscalls" |
| Attempt to count the number of read I/O operations\(emthat is, |
| system calls such as |
| .BR read (2) |
| and |
| .BR pread (2). |
| .TP |
| .IR syscw ": write syscalls" |
| Attempt to count the number of write I/O operations\(emthat is, |
| system calls such as |
| .BR write (2) |
| and |
| .BR pwrite (2). |
| .TP |
| .IR read_bytes ": bytes read" |
| Attempt to count the number of bytes which this process really did cause to |
| be fetched from the storage layer. |
| This is accurate for block-backed filesystems. |
| .TP |
| .IR write_bytes ": bytes written" |
| Attempt to count the number of bytes which this process caused to be sent to |
| the storage layer. |
| .TP |
| .IR cancelled_write_bytes : |
| The big inaccuracy here is truncate. |
| If a process writes 1 MB to a file and then deletes the file, |
| it will in fact perform no writeout. |
| But it will have been accounted as having caused 1 MB of write. |
| In other words: this field represents the number of bytes which this process |
| caused to not happen, by truncating pagecache. |
| A task can cause "negative" I/O too. |
| If this task truncates some dirty pagecache, |
| some I/O which another task has been accounted for |
| (in its |
| .IR write_bytes ) |
| will not be happening. |
| .RE |
| .IP |
| .IR Note : |
| In the current implementation, things are a bit racy on 32-bit systems: |
| if process A reads process B's |
| .I /proc/[pid]/io |
| while process B is updating one of these 64-bit counters, |
| process A could see an intermediate result. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[pid]/limits " (since Linux 2.6.24)" |
| This file displays the soft limit, hard limit, and units of measurement |
| for each of the process's resource limits (see |
| .BR getrlimit (2)). |
| Up to and including Linux 2.6.35, |
| this file is protected to allow reading only by the real UID of the process. |
| Since Linux 2.6.36, |
| .\" commit 3036e7b490bf7878c6dae952eec5fb87b1106589 |
| this file is readable by all users on the system. |
| .\" FIXME Describe /proc/[pid]/loginuid |
| .\" Added in 2.6.11; updating requires CAP_AUDIT_CONTROL |
| .\" CONFIG_AUDITSYSCALL |
| .TP |
| .IR /proc/[pid]/map_files/ " (since kernel 3.3)" |
| .\" commit 640708a2cff7f81e246243b0073c66e6ece7e53e |
| This subdirectory contains entries corresponding to memory-mapped |
| files (see |
| .BR mmap (2)). |
| Entries are named by memory region start and end |
| address pair (expressed as hexadecimal numbers), |
| and are symbolic links to the mapped files themselves. |
| Here is an example, with the output wrapped and reformatted to fit on an 80-column display: |
| .IP |
| .in +4n |
| .EX |
| .RB "#" " ls \-l /proc/self/map_files/" |
| lr\-\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:31 |
| 3252e00000\-3252e20000 \-> /usr/lib64/ld\-2.15.so |
| \&... |
| .EE |
| .in |
| .IP |
| Although these entries are present for memory regions that were |
| mapped with the |
| .BR MAP_FILE |
| flag, the way anonymous shared memory (regions created with the |
| .B MAP_ANON | MAP_SHARED |
| flags) |
| is implemented in Linux |
| means that such regions also appear on this directory. |
| Here is an example where the target file is the deleted |
| .I /dev/zero |
| one: |
| .IP |
| .in +4n |
| .EX |
| lrw\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:33 |
| 7fc075d2f000\-7fc075e6f000 \-> /dev/zero (deleted) |
| .EE |
| .in |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .IP |
| Until kernel version 4.3, |
| .\" commit bdb4d100afe9818aebd1d98ced575c5ef143456c |
| this directory appeared only if the |
| .B CONFIG_CHECKPOINT_RESTORE |
| kernel configuration option was enabled. |
| .IP |
| Capabilities are required to read the contents of the symbolic links in |
| this directory: before Linux 5.9, the reading process requires |
| .BR CAP_SYS_ADMIN |
| in the initial user namespace; |
| since Linux 5.9, the reading process must have either |
| .BR CAP_SYS_ADMIN |
| or |
| .BR CAP_CHECKPOINT_RESTORE |
| in the user namespace where it resides. |
| .TP |
| .I /proc/[pid]/maps |
| A file containing the currently mapped memory regions and their access |
| permissions. |
| See |
| .BR mmap (2) |
| for some further information about memory mappings. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .IP |
| The format of the file is: |
| .IP |
| .in +4n |
| .EX |
| .I "address perms offset dev inode pathname" |
| 00400000\-00452000 r\-xp 00000000 08:02 173521 /usr/bin/dbus\-daemon |
| 00651000\-00652000 r\-\-p 00051000 08:02 173521 /usr/bin/dbus\-daemon |
| 00652000\-00655000 rw\-p 00052000 08:02 173521 /usr/bin/dbus\-daemon |
| 00e03000\-00e24000 rw\-p 00000000 00:00 0 [heap] |
| 00e24000\-011f7000 rw\-p 00000000 00:00 0 [heap] |
| \&... |
| 35b1800000\-35b1820000 r\-xp 00000000 08:02 135522 /usr/lib64/ld\-2.15.so |
| 35b1a1f000\-35b1a20000 r\-\-p 0001f000 08:02 135522 /usr/lib64/ld\-2.15.so |
| 35b1a20000\-35b1a21000 rw\-p 00020000 08:02 135522 /usr/lib64/ld\-2.15.so |
| 35b1a21000\-35b1a22000 rw\-p 00000000 00:00 0 |
| 35b1c00000\-35b1dac000 r\-xp 00000000 08:02 135870 /usr/lib64/libc\-2.15.so |
| 35b1dac000\-35b1fac000 \-\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so |
| 35b1fac000\-35b1fb0000 r\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so |
| 35b1fb0000\-35b1fb2000 rw\-p 001b0000 08:02 135870 /usr/lib64/libc\-2.15.so |
| \&... |
| f2c6ff8c000\-7f2c7078c000 rw\-p 00000000 00:00 0 [stack:986] |
| \&... |
| 7fffb2c0d000\-7fffb2c2e000 rw\-p 00000000 00:00 0 [stack] |
| 7fffb2d48000\-7fffb2d49000 r\-xp 00000000 00:00 0 [vdso] |
| .EE |
| .in |
| .IP |
| The |
| .I address |
| field is the address space in the process that the mapping occupies. |
| The |
| .I perms |
| field is a set of permissions: |
| .IP |
| .in +4n |
| .EX |
| r = read |
| w = write |
| x = execute |
| s = shared |
| p = private (copy on write) |
| .EE |
| .in |
| .IP |
| The |
| .I offset |
| field is the offset into the file/whatever; |
| .I dev |
| is the device |
| (major:minor); |
| .I inode |
| is the inode on that device. |
| 0 indicates that no inode is associated with the memory region, |
| as would be the case with BSS (uninitialized data). |
| .IP |
| The |
| .I pathname |
| field will usually be the file that is backing the mapping. |
| For ELF files, |
| you can easily coordinate with the |
| .I offset |
| field by looking at the |
| Offset field in the ELF program headers |
| .RI ( "readelf\ \-l" ). |
| .IP |
| There are additional helpful pseudo-paths: |
| .RS |
| .TP |
| .IR [stack] |
| The initial process's (also known as the main thread's) stack. |
| .TP |
| .IR [stack:<tid>] " (from Linux 3.4 to 4.4)" |
| .\" commit b76437579d1344b612cf1851ae610c636cec7db0 (added) |
| .\" commit 65376df582174ffcec9e6471bf5b0dd79ba05e4a (removed) |
| A thread's stack (where the |
| .IR <tid> |
| is a thread ID). |
| It corresponds to the |
| .IR /proc/[pid]/task/[tid]/ |
| path. |
| This field was removed in Linux 4.5, since providing this information |
| for a process with large numbers of threads is expensive. |
| .TP |
| .IR [vdso] |
| The virtual dynamically linked shared object. |
| See |
| .BR vdso (7). |
| .TP |
| .IR [heap] |
| The process's heap. |
| .in |
| .RE |
| .IP |
| If the |
| .I pathname |
| field is blank, |
| this is an anonymous mapping as obtained via |
| .BR mmap (2). |
| There is no easy way to coordinate this back to a process's source, |
| short of running it through |
| .BR gdb (1), |
| .BR strace (1), |
| or similar. |
| .IP |
| .I pathname |
| is shown unescaped except for newline characters, which are replaced |
| with an octal escape sequence. |
| As a result, it is not possible to determine whether the original |
| pathname contained a newline character or the literal |
| .I \e012 |
| character sequence. |
| .IP |
| If the mapping is file-backed and the file has been deleted, the string |
| " (deleted)" is appended to the pathname. |
| Note that this is ambiguous too. |
| .IP |
| Under Linux 2.0, there is no field giving pathname. |
| .TP |
| .I /proc/[pid]/mem |
| This file can be used to access the pages of a process's memory through |
| .BR open (2), |
| .BR read (2), |
| and |
| .BR lseek (2). |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_ATTACH_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[pid]/mountinfo " (since Linux 2.6.26)" |
| .\" This info adapted from Documentation/filesystems/proc.txt |
| .\" commit 2d4d4864ac08caff5c204a752bd004eed4f08760 |
| This file contains information about mount points |
| in the process's mount namespace (see |
| .BR mount_namespaces (7)). |
| It supplies various information |
| (e.g., propagation state, root of mount for bind mounts, |
| identifier for each mount and its parent) that is missing from the (older) |
| .IR /proc/[pid]/mounts |
| file, and fixes various other problems with that file |
| (e.g., nonextensibility, |
| failure to distinguish per-mount versus per-superblock options). |
| .IP |
| The file contains lines of the form: |
| .IP |
| .EX |
| 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 \- ext3 /dev/root rw,errors=continue |
| (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11) |
| .EE |
| .IP |
| The numbers in parentheses are labels for the descriptions below: |
| .RS 7 |
| .TP 5 |
| (1) |
| mount ID: a unique ID for the mount (may be reused after |
| .BR umount (2)). |
| .TP |
| (2) |
| parent ID: the ID of the parent mount |
| (or of self for the root of this mount namespace's mount tree). |
| .IP |
| If a new mount is stacked on top of a previous existing mount |
| (so that it hides the existing mount) at pathname P, |
| then the parent of the new mount is the previous mount at that location. |
| Thus, when looking at all the mounts stacked at a particular location, |
| the top-most mount is the one that is not the parent |
| of any other mount at the same location. |
| (Note, however, that this top-most mount will be accessible only if |
| the longest path subprefix of P that is a mount point |
| is not itself hidden by a stacked mount.) |
| .IP |
| If the parent mount point lies outside the process's root directory (see |
| .BR chroot (2)), |
| the ID shown here won't have a corresponding record in |
| .I mountinfo |
| whose mount ID (field 1) matches this parent mount ID |
| (because mount points that lie outside the process's root directory |
| are not shown in |
| .IR mountinfo ). |
| As a special case of this point, |
| the process's root mount point may have a parent mount |
| (for the initramfs filesystem) that lies |
| .\" Miklos Szeredi, Nov 2017: The hidden one is the initramfs, I believe |
| .\" mtk: In the initial mount namespace, this hidden ID has the value 0 |
| outside the process's root directory, |
| and an entry for that mount point will not appear in |
| .IR mountinfo . |
| .TP |
| (3) |
| major:minor: the value of |
| .I st_dev |
| for files on this filesystem (see |
| .BR stat (2)). |
| .TP |
| (4) |
| root: the pathname of the directory in the filesystem |
| which forms the root of this mount. |
| .TP |
| (5) |
| mount point: the pathname of the mount point relative |
| to the process's root directory. |
| .TP |
| (6) |
| mount options: per-mount options (see |
| .BR mount (2)). |
| .TP |
| (7) |
| optional fields: zero or more fields of the form "tag[:value]"; see below. |
| .TP |
| (8) |
| separator: the end of the optional fields is marked by a single hyphen. |
| .TP |
| (9) |
| filesystem type: the filesystem type in the form "type[.subtype]". |
| .TP |
| (10) |
| mount source: filesystem-specific information or "none". |
| .TP |
| (11) |
| super options: per-superblock options (see |
| .BR mount (2)). |
| .RE |
| .IP |
| Currently, the possible optional fields are |
| .IR shared , |
| .IR master , |
| .IR propagate_from , |
| and |
| .IR unbindable . |
| See |
| .BR mount_namespaces (7) |
| for a description of these fields. |
| Parsers should ignore all unrecognized optional fields. |
| .IP |
| For more information on mount propagation see: |
| .I Documentation/filesystems/sharedsubtree.txt |
| in the Linux kernel source tree. |
| .TP |
| .IR /proc/[pid]/mounts " (since Linux 2.4.19)" |
| This file lists all the filesystems currently mounted in the |
| process's mount namespace (see |
| .BR mount_namespaces (7)). |
| The format of this file is documented in |
| .BR fstab (5). |
| .IP |
| Since kernel version 2.6.15, this file is pollable: |
| after opening the file for reading, a change in this file |
| (i.e., a filesystem mount or unmount) causes |
| .BR select (2) |
| to mark the file descriptor as having an exceptional condition, and |
| .BR poll (2) |
| and |
| .BR epoll_wait (2) |
| mark the file as having a priority event |
| .RB ( POLLPRI ). |
| (Before Linux 2.6.30, |
| a change in this file was indicated by the file descriptor |
| being marked as readable for |
| .BR select (2), |
| and being marked as having an error condition for |
| .BR poll (2) |
| and |
| .BR epoll_wait (2).) |
| .TP |
| .IR /proc/[pid]/mountstats " (since Linux 2.6.17)" |
| This file exports information (statistics, configuration information) |
| about the mount points in the process's mount namespace (see |
| .BR mount_namespaces (7)). |
| Lines in this file have the form: |
| .IP |
| .in +4n |
| .EX |
| device /dev/sda7 mounted on /home with fstype ext3 [stats] |
| ( 1 ) ( 2 ) (3 ) ( 4 ) |
| .EE |
| .in |
| .IP |
| The fields in each line are: |
| .RS 7 |
| .TP 5 |
| (1) |
| The name of the mounted device |
| (or "nodevice" if there is no corresponding device). |
| .TP |
| (2) |
| The mount point within the filesystem tree. |
| .TP |
| (3) |
| The filesystem type. |
| .TP |
| (4) |
| Optional statistics and configuration information. |
| Currently (as at Linux 2.6.26), only NFS filesystems export |
| information via this field. |
| .RE |
| .IP |
| This file is readable only by the owner of the process. |
| .TP |
| .IR /proc/[pid]/net " (since Linux 2.6.25)" |
| See the description of |
| .IR /proc/net . |
| .TP |
| .IR /proc/[pid]/ns/ " (since Linux 3.0)" |
| .\" See commit 6b4e306aa3dc94a0545eb9279475b1ab6209a31f |
| This is a subdirectory containing one entry for each namespace that |
| supports being manipulated by |
| .BR setns (2). |
| For more information, see |
| .BR namespaces (7). |
| .TP |
| .IR /proc/[pid]/numa_maps " (since Linux 2.6.14)" |
| See |
| .BR numa (7). |
| .TP |
| .IR /proc/[pid]/oom_adj " (since Linux 2.6.11)" |
| This file can be used to adjust the score used to select which process |
| should be killed in an out-of-memory (OOM) situation. |
| The kernel uses this value for a bit-shift operation of the process's |
| .IR oom_score |
| value: |
| valid values are in the range \-16 to +15, |
| plus the special value \-17, |
| which disables OOM-killing altogether for this process. |
| A positive score increases the likelihood of this |
| process being killed by the OOM-killer; |
| a negative score decreases the likelihood. |
| .IP |
| The default value for this file is 0; |
| a new process inherits its parent's |
| .I oom_adj |
| setting. |
| A process must be privileged |
| .RB ( CAP_SYS_RESOURCE ) |
| to update this file. |
| .IP |
| Since Linux 2.6.36, use of this file is deprecated in favor of |
| .IR /proc/[pid]/oom_score_adj . |
| .TP |
| .IR /proc/[pid]/oom_score " (since Linux 2.6.11)" |
| .\" See mm/oom_kill.c::badness() in pre 2.6.36 sources |
| .\" See mm/oom_kill.c::oom_badness() after 2.6.36 |
| .\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10 |
| This file displays the current score that the kernel gives to |
| this process for the purpose of selecting a process |
| for the OOM-killer. |
| A higher score means that the process is more likely to be |
| selected by the OOM-killer. |
| The basis for this score is the amount of memory used by the process, |
| with increases (+) or decreases (\-) for factors including: |
| .\" See mm/oom_kill.c::badness() in pre 2.6.36 sources |
| .\" See mm/oom_kill.c::oom_badness() after 2.6.36 |
| .\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10 |
| .RS |
| .IP * 2 |
| whether the process is privileged (\-). |
| .\" More precisely, if it has CAP_SYS_ADMIN or (pre 2.6.36) CAP_SYS_RESOURCE |
| .RE |
| .IP |
| Before kernel 2.6.36 the following factors were also used in the calculation of oom_score: |
| .RS |
| .IP * 2 |
| whether the process creates a lot of children using |
| .BR fork (2) |
| (+); |
| .IP * |
| whether the process has been running a long time, |
| or has used a lot of CPU time (\-); |
| .IP * |
| whether the process has a low nice value (i.e., > 0) (+); and |
| .IP * |
| whether the process is making direct hardware access (\-). |
| .\" More precisely, if it has CAP_SYS_RAWIO |
| .RE |
| .IP |
| The |
| .I oom_score |
| also reflects the adjustment specified by the |
| .I oom_score_adj |
| or |
| .I oom_adj |
| setting for the process. |
| .TP |
| .IR /proc/[pid]/oom_score_adj " (since Linux 2.6.36)" |
| .\" Text taken from 3.7 Documentation/filesystems/proc.txt |
| This file can be used to adjust the badness heuristic used to select which |
| process gets killed in out-of-memory conditions. |
| .IP |
| The badness heuristic assigns a value to each candidate task ranging from 0 |
| (never kill) to 1000 (always kill) to determine which process is targeted. |
| The units are roughly a proportion along that range of |
| allowed memory the process may allocate from, |
| based on an estimation of its current memory and swap use. |
| For example, if a task is using all allowed memory, |
| its badness score will be 1000. |
| If it is using half of its allowed memory, its score will be 500. |
| .IP |
| There is an additional factor included in the badness score: root |
| processes are given 3% extra memory over other tasks. |
| .IP |
| The amount of "allowed" memory depends on the context |
| in which the OOM-killer was called. |
| If it is due to the memory assigned to the allocating task's cpuset |
| being exhausted, |
| the allowed memory represents the set of mems assigned to that |
| cpuset (see |
| .BR cpuset (7)). |
| If it is due to a mempolicy's node(s) being exhausted, |
| the allowed memory represents the set of mempolicy nodes. |
| If it is due to a memory limit (or swap limit) being reached, |
| the allowed memory is that configured limit. |
| Finally, if it is due to the entire system being out of memory, the |
| allowed memory represents all allocatable resources. |
| .IP |
| The value of |
| .I oom_score_adj |
| is added to the badness score before it |
| is used to determine which task to kill. |
| Acceptable values range from \-1000 |
| (OOM_SCORE_ADJ_MIN) to +1000 (OOM_SCORE_ADJ_MAX). |
| This allows user space to control the preference for OOM-killing, |
| ranging from always preferring a certain |
| task or completely disabling it from OOM killing. |
| The lowest possible value, \-1000, is |
| equivalent to disabling OOM-killing entirely for that task, |
| since it will always report a badness score of 0. |
| .IP |
| Consequently, it is very simple for user space to define |
| the amount of memory to consider for each task. |
| Setting an |
| .I oom_score_adj |
| value of +500, for example, |
| is roughly equivalent to allowing the remainder of tasks sharing the |
| same system, cpuset, mempolicy, or memory controller resources |
| to use at least 50% more memory. |
| A value of \-500, on the other hand, would be roughly |
| equivalent to discounting 50% of the task's |
| allowed memory from being considered as scoring against the task. |
| .IP |
| For backward compatibility with previous kernels, |
| .I /proc/[pid]/oom_adj |
| can still be used to tune the badness score. |
| Its value is |
| scaled linearly with |
| .IR oom_score_adj . |
| .IP |
| Writing to |
| .IR /proc/[pid]/oom_score_adj |
| or |
| .IR /proc/[pid]/oom_adj |
| will change the other with its scaled value. |
| .IP |
| The |
| .BR choom (1) |
| program provides a command-line interface for adjusting the |
| .I oom_score_adj |
| value of a running process or a newly executed command. |
| .TP |
| .IR /proc/[pid]/pagemap " (since Linux 2.6.25)" |
| This file shows the mapping of each of the process's virtual pages |
| into physical page frames or swap area. |
| It contains one 64-bit value for each virtual page, |
| with the bits set as follows: |
| .RS |
| .TP |
| 63 |
| If set, the page is present in RAM. |
| .TP |
| 62 |
| If set, the page is in swap space |
| .TP |
| 61 (since Linux 3.5) |
| The page is a file-mapped page or a shared anonymous page. |
| .TP |
| 60\(en57 (since Linux 3.11) |
| Zero |
| .\" Not quite true; see commit 541c237c0923f567c9c4cabb8a81635baadc713f |
| .TP |
| 56 (since Linux 4.2) |
| .\" commit 77bb499bb60f4b79cca7d139c8041662860fcf87 |
| .\" commit 83b4b0bb635eee2b8e075062e4e008d1bc110ed7 |
| The page is exclusively mapped. |
| .TP |
| 55 (since Linux 3.11) |
| PTE is soft-dirty |
| (see the kernel source file |
| .IR Documentation/admin\-guide/mm/soft\-dirty.rst ). |
| .TP |
| 54\(en0 |
| If the page is present in RAM (bit 63), then these bits |
| provide the page frame number, which can be used to index |
| .IR /proc/kpageflags |
| and |
| .IR /proc/kpagecount . |
| If the page is present in swap (bit 62), |
| then bits 4\(en0 give the swap type, and bits 54\(en5 encode the swap offset. |
| .RE |
| .IP |
| Before Linux 3.11, bits 60\(en55 were |
| used to encode the base-2 log of the page size. |
| .IP |
| To employ |
| .IR /proc/[pid]/pagemap |
| efficiently, use |
| .IR /proc/[pid]/maps |
| to determine which areas of memory are actually mapped and seek |
| to skip over unmapped regions. |
| .IP |
| The |
| .IR /proc/[pid]/pagemap |
| file is present only if the |
| .B CONFIG_PROC_PAGE_MONITOR |
| kernel configuration option is enabled. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[pid]/personality " (since Linux 2.6.28)" |
| .\" commit 478307230810d7e2a753ed220db9066dfdf88718 |
| This read-only file exposes the process's execution domain, as set by |
| .BR personality (2). |
| The value is displayed in hexadecimal notation. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_ATTACH_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .I /proc/[pid]/root |
| UNIX and Linux support the idea of a per-process root of the |
| filesystem, set by the |
| .BR chroot (2) |
| system call. |
| This file is a symbolic link that points to the process's |
| root directory, and behaves in the same way as |
| .IR exe , |
| and |
| .IR fd/* . |
| .IP |
| Note however that this file is not merely a symbolic link. |
| It provides the same view of the filesystem (including namespaces and the |
| set of per-process mounts) as the process itself. |
| An example illustrates this point. |
| In one terminal, we start a shell in new user and mount namespaces, |
| and in that shell we create some new mount points: |
| .IP |
| .in +4n |
| .EX |
| $ \fBPS1=\(aqsh1# \(aq unshare \-Urnm\fP |
| sh1# \fBmount \-t tmpfs tmpfs /etc\fP # Mount empty tmpfs at /etc |
| sh1# \fBmount \-\-bind /usr /dev\fP # Mount /usr at /dev |
| sh1# \fBecho $$\fP |
| 27123 |
| .EE |
| .in |
| .IP |
| In a second terminal window, in the initial mount namespace, |
| we look at the contents of the corresponding mounts in |
| the initial and new namespaces: |
| .IP |
| .in +4n |
| .EX |
| $ \fBPS1=\(aqsh2# \(aq sudo sh\fP |
| sh2# \fBls /etc | wc \-l\fP # In initial NS |
| 309 |
| sh2# \fBls /proc/27123/root/etc | wc \-l\fP # /etc in other NS |
| 0 # The empty tmpfs dir |
| sh2# \fBls /dev | wc \-l\fP # In initial NS |
| 205 |
| sh2# \fBls /proc/27123/root/dev | wc \-l\fP # /dev in other NS |
| 11 # Actually bind |
| # mounted to /usr |
| sh2# \fBls /usr | wc \-l\fP # /usr in initial NS |
| 11 |
| .EE |
| .in |
| .IP |
| .\" The following was still true as at kernel 2.6.13 |
| In a multithreaded process, the contents of the |
| .I /proc/[pid]/root |
| symbolic link are not available if the main thread has already terminated |
| (typically by calling |
| .BR pthread_exit (3)). |
| .IP |
| Permission to dereference or read |
| .RB ( readlink (2)) |
| this symbolic link is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .\" FIXME Describe /proc/[pid]/projid_map |
| .\" Added in 3.7 |
| .\" commit f76d207a66c3a53defea67e7d36c3eb1b7d6d61d |
| .TP |
| .IR /proc/[pid]/seccomp " (Linux 2.6.12 to 2.6.22)" |
| This file can be used to read and change the process's |
| secure computing (seccomp) mode setting. |
| It contains the value 0 if the process is not in seccomp mode, |
| and 1 if the process is in strict seccomp mode (see |
| .BR seccomp (2)). |
| Writing 1 to this file places the process irreversibly in strict seccomp mode. |
| (Further attempts to write to the file fail with the |
| .B EPERM |
| error.) |
| .IP |
| In Linux 2.6.23, |
| this file went away, to be replaced by the |
| .BR prctl (2) |
| .BR PR_GET_SECCOMP |
| and |
| .BR PR_SET_SECCOMP |
| operations (and later by |
| .BR seccomp (2) |
| and the |
| .I Seccomp |
| field in |
| .IR /proc/[pid]/status ). |
| .\" FIXME Describe /proc/[pid]/sessionid |
| .\" commit 1e0bd7550ea9cf474b1ad4c6ff5729a507f75fdc |
| .\" CONFIG_AUDITSYSCALL |
| .\" Added in 2.6.25; read-only; only readable by real UID |
| .\" |
| .\" FIXME Describe /proc/[pid]/sched |
| .\" Added in 2.6.23 |
| .\" CONFIG_SCHED_DEBUG, and additional fields if CONFIG_SCHEDSTATS |
| .\" Displays various scheduling parameters |
| .\" This file can be written, to reset stats |
| .\" The set of fields exposed by this file have changed |
| .\" significantly over time. |
| .\" commit 43ae34cb4cd650d1eb4460a8253a8e747ba052ac |
| .\" |
| .\" FIXME Describe /proc/[pid]/schedstats and |
| .\" /proc/[pid]/task/[tid]/schedstats |
| .\" Added in 2.6.9 |
| .\" CONFIG_SCHEDSTATS |
| .TP |
| .IR /proc/[pid]/setgroups " (since Linux 3.19)" |
| See |
| .BR user_namespaces (7). |
| .TP |
| .IR /proc/[pid]/smaps " (since Linux 2.6.14)" |
| This file shows memory consumption for each of the process's mappings. |
| (The |
| .BR pmap (1) |
| command displays similar information, |
| in a form that may be easier for parsing.) |
| For each mapping there is a series of lines such as the following: |
| .IP |
| .in +4n |
| .EX |
| 00400000\-0048a000 r\-xp 00000000 fd:03 960637 /bin/bash |
| Size: 552 kB |
| Rss: 460 kB |
| Pss: 100 kB |
| Shared_Clean: 452 kB |
| Shared_Dirty: 0 kB |
| Private_Clean: 8 kB |
| Private_Dirty: 0 kB |
| Referenced: 460 kB |
| Anonymous: 0 kB |
| AnonHugePages: 0 kB |
| ShmemHugePages: 0 kB |
| ShmemPmdMapped: 0 kB |
| Swap: 0 kB |
| KernelPageSize: 4 kB |
| MMUPageSize: 4 kB |
| KernelPageSize: 4 kB |
| MMUPageSize: 4 kB |
| Locked: 0 kB |
| ProtectionKey: 0 |
| VmFlags: rd ex mr mw me dw |
| .EE |
| .in |
| .IP |
| The first of these lines shows the same information as is displayed |
| for the mapping in |
| .IR /proc/[pid]/maps . |
| The following lines show the size of the mapping, |
| the amount of the mapping that is currently resident in RAM ("Rss"), |
| the process's proportional share of this mapping ("Pss"), |
| the number of clean and dirty shared pages in the mapping, |
| and the number of clean and dirty private pages in the mapping. |
| "Referenced" indicates the amount of memory currently marked as |
| referenced or accessed. |
| "Anonymous" shows the amount of memory |
| that does not belong to any file. |
| "Swap" shows how much |
| would-be-anonymous memory is also used, but out on swap. |
| .IP |
| The "KernelPageSize" line (available since Linux 2.6.29) |
| is the page size used by the kernel to back the virtual memory area. |
| This matches the size used by the MMU in the majority of cases. |
| However, one counter-example occurs on PPC64 kernels |
| whereby a kernel using 64 kB as a base page size may still use 4 kB |
| pages for the MMU on older processors. |
| To distinguish the two attributes, the "MMUPageSize" line |
| (also available since Linux 2.6.29) |
| reports the page size used by the MMU. |
| .IP |
| The "Locked" indicates whether the mapping is locked in memory |
| or not. |
| .IP |
| The "ProtectionKey" line (available since Linux 4.9, on x86 only) |
| contains the memory protection key (see |
| .BR pkeys (7)) |
| associated with the virtual memory area. |
| This entry is present only if the kernel was built with the |
| .B CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS |
| configuration option (since Linux 4.6). |
| .IP |
| The "VmFlags" line (available since Linux 3.8) |
| represents the kernel flags associated with the virtual memory area, |
| encoded using the following two-letter codes: |
| .IP |
| rd - readable |
| wr - writable |
| ex - executable |
| sh - shared |
| mr - may read |
| mw - may write |
| me - may execute |
| ms - may share |
| gd - stack segment grows down |
| pf - pure PFN range |
| dw - disabled write to the mapped file |
| lo - pages are locked in memory |
| io - memory mapped I/O area |
| sr - sequential read advise provided |
| rr - random read advise provided |
| dc - do not copy area on fork |
| de - do not expand area on remapping |
| ac - area is accountable |
| nr - swap space is not reserved for the area |
| ht - area uses huge tlb pages |
| sf - perform synchronous page faults (since Linux 4.15) |
| nl - non-linear mapping (removed in Linux 4.0) |
| ar - architecture specific flag |
| wf - wipe on fork (since Linux 4.14) |
| dd - do not include area into core dump |
| sd - soft-dirty flag (since Linux 3.13) |
| mm - mixed map area |
| hg - huge page advise flag |
| nh - no-huge page advise flag |
| mg - mergeable advise flag |
| um - userfaultfd missing pages tracking (since Linux 4.3) |
| uw - userfaultfd wprotect pages tracking (since Linux 4.3) |
| .IP |
| The |
| .IR /proc/[pid]/smaps |
| file is present only if the |
| .B CONFIG_PROC_PAGE_MONITOR |
| kernel configuration option is enabled. |
| .TP |
| .IR /proc/[pid]/stack " (since Linux 2.6.29)" |
| .\" 2ec220e27f5040aec1e88901c1b6ea3d135787ad |
| This file provides a symbolic trace of the function calls in this |
| process's kernel stack. |
| This file is provided only if the kernel was built with the |
| .B CONFIG_STACKTRACE |
| configuration option. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_ATTACH_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .I /proc/[pid]/stat |
| Status information about the process. |
| This is used by |
| .BR ps (1). |
| It is defined in the kernel source file |
| .IR fs/proc/array.c "." |
| .IP |
| The fields, in order, with their proper |
| .BR scanf (3) |
| format specifiers, are listed below. |
| Whether or not certain of these fields display valid information is governed by |
| a ptrace access mode |
| .BR PTRACE_MODE_READ_FSCREDS "\ |\ " PTRACE_MODE_NOAUDIT |
| check (refer to |
| .BR ptrace (2)). |
| If the check denies access, then the field value is displayed as 0. |
| The affected fields are indicated with the marking [PT]. |
| .RS |
| .TP |
| (1) \fIpid\fP \ %d |
| .br |
| The process ID. |
| .TP |
| (2) \fIcomm\fP \ %s |
| The filename of the executable, in parentheses. |
| Strings longer than |
| .B TASK_COMM_LEN |
| (16) characters (including the terminating null byte) are silently truncated. |
| This is visible whether or not the executable is swapped out. |
| .TP |
| (3) \fIstate\fP \ %c |
| One of the following characters, indicating process state: |
| .RS |
| .IP R 3 |
| Running |
| .IP S |
| Sleeping in an interruptible wait |
| .IP D |
| Waiting in uninterruptible |
| disk sleep |
| .IP Z |
| Zombie |
| .IP T |
| Stopped (on a signal) or (before Linux 2.6.33) trace stopped |
| .IP t |
| .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 |
| Tracing stop (Linux 2.6.33 onward) |
| .IP W |
| Paging (only before Linux 2.6.0) |
| .IP X |
| Dead (from Linux 2.6.0 onward) |
| .IP x |
| .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 |
| Dead (Linux 2.6.33 to |
| .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 |
| 3.13 only) |
| .IP K |
| .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 |
| Wakekill (Linux 2.6.33 to |
| .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 |
| 3.13 only) |
| .IP W |
| .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 |
| Waking (Linux 2.6.33 to |
| .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 |
| 3.13 only) |
| .IP P |
| .\" commit f2530dc71cf0822f90bb63ea4600caaef33a66bb |
| Parked (Linux 3.9 to |
| .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 |
| 3.13 only) |
| .RE |
| .TP |
| (4) \fIppid\fP \ %d |
| The PID of the parent of this process. |
| .TP |
| (5) \fIpgrp\fP \ %d |
| The process group ID of the process. |
| .TP |
| (6) \fIsession\fP \ %d |
| The session ID of the process. |
| .TP |
| (7) \fItty_nr\fP \ %d |
| The controlling terminal of the process. |
| (The minor device number is contained in the combination of bits |
| 31 to 20 and 7 to 0; |
| the major device number is in bits 15 to 8.) |
| .TP |
| (8) \fItpgid\fP \ %d |
| .\" This field and following, up to and including wchan added 0.99.1 |
| The ID of the foreground process group of the controlling |
| terminal of the process. |
| .TP |
| (9) \fIflags\fP \ %u |
| The kernel flags word of the process. |
| For bit meanings, |
| see the PF_* defines in the Linux kernel source file |
| .IR include/linux/sched.h . |
| Details depend on the kernel version. |
| .IP |
| The format for this field was %lu before Linux 2.6. |
| .TP |
| (10) \fIminflt\fP \ %lu |
| The number of minor faults the process has made which have not |
| required loading a memory page from disk. |
| .TP |
| (11) \fIcminflt\fP \ %lu |
| The number of minor faults that the process's |
| waited-for children have made. |
| .TP |
| (12) \fImajflt\fP \ %lu |
| The number of major faults the process has made which have |
| required loading a memory page from disk. |
| .TP |
| (13) \fIcmajflt\fP \ %lu |
| The number of major faults that the process's |
| waited-for children have made. |
| .TP |
| (14) \fIutime\fP \ %lu |
| Amount of time that this process has been scheduled in user mode, |
| measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| This includes guest time, \fIguest_time\fP |
| (time spent running a virtual CPU, see below), |
| so that applications that are not aware of the guest time field |
| do not lose that time from their calculations. |
| .TP |
| (15) \fIstime\fP \ %lu |
| Amount of time that this process has been scheduled in kernel mode, |
| measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .TP |
| (16) \fIcutime\fP \ %ld |
| Amount of time that this process's |
| waited-for children have been scheduled in user mode, |
| measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| (See also |
| .BR times (2).) |
| This includes guest time, \fIcguest_time\fP |
| (time spent running a virtual CPU, see below). |
| .TP |
| (17) \fIcstime\fP \ %ld |
| Amount of time that this process's |
| waited-for children have been scheduled in kernel mode, |
| measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .TP |
| (18) \fIpriority\fP \ %ld |
| (Explanation for Linux 2.6) |
| For processes running a real-time scheduling policy |
| .RI ( policy |
| below; see |
| .BR sched_setscheduler (2)), |
| this is the negated scheduling priority, minus one; |
| that is, a number in the range \-2 to \-100, |
| corresponding to real-time priorities 1 to 99. |
| For processes running under a non-real-time scheduling policy, |
| this is the raw nice value |
| .RB ( setpriority (2)) |
| as represented in the kernel. |
| The kernel stores nice values as numbers |
| in the range 0 (high) to 39 (low), |
| corresponding to the user-visible nice range of \-20 to 19. |
| .IP |
| Before Linux 2.6, this was a scaled value based on |
| the scheduler weighting given to this process. |
| .\" And back in kernel 1.2 days things were different again. |
| .TP |
| (19) \fInice\fP \ %ld |
| The nice value (see |
| .BR setpriority (2)), |
| a value in the range 19 (low priority) to \-20 (high priority). |
| .\" Back in kernel 1.2 days things were different. |
| .\" .TP |
| .\" \fIcounter\fP %ld |
| .\" The current maximum size in jiffies of the process's next timeslice, |
| .\" or what is currently left of its current timeslice, if it is the |
| .\" currently running process. |
| .\" .TP |
| .\" \fItimeout\fP %u |
| .\" The time in jiffies of the process's next timeout. |
| .\" timeout was removed sometime around 2.1/2.2 |
| .TP |
| (20) \fInum_threads\fP \ %ld |
| Number of threads in this process (since Linux 2.6). |
| Before kernel 2.6, this field was hard coded to 0 as a placeholder |
| for an earlier removed field. |
| .TP |
| (21) \fIitrealvalue\fP \ %ld |
| The time in jiffies before the next |
| .B SIGALRM |
| is sent to the process due to an interval timer. |
| Since kernel 2.6.17, this field is no longer maintained, |
| and is hard coded as 0. |
| .TP |
| (22) \fIstarttime\fP \ %llu |
| The time the process started after system boot. |
| In kernels before Linux 2.6, this value was expressed in jiffies. |
| Since Linux 2.6, the value is expressed in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .IP |
| The format for this field was %lu before Linux 2.6. |
| .TP |
| (23) \fIvsize\fP \ %lu |
| Virtual memory size in bytes. |
| .TP |
| (24) \fIrss\fP \ %ld |
| Resident Set Size: number of pages the process has in real memory. |
| This is just the pages which |
| count toward text, data, or stack space. |
| This does not include pages |
| which have not been demand-loaded in, or which are swapped out. |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| below. |
| .TP |
| (25) \fIrsslim\fP \ %lu |
| Current soft limit in bytes on the rss of the process; |
| see the description of |
| .B RLIMIT_RSS |
| in |
| .BR getrlimit (2). |
| .TP |
| (26) \fIstartcode\fP \ %lu \ [PT] |
| The address above which program text can run. |
| .TP |
| (27) \fIendcode\fP \ %lu \ [PT] |
| The address below which program text can run. |
| .TP |
| (28) \fIstartstack\fP \ %lu \ [PT] |
| The address of the start (i.e., bottom) of the stack. |
| .TP |
| (29) \fIkstkesp\fP \ %lu \ [PT] |
| The current value of ESP (stack pointer), as found in the |
| kernel stack page for the process. |
| .TP |
| (30) \fIkstkeip\fP \ %lu \ [PT] |
| The current EIP (instruction pointer). |
| .TP |
| (31) \fIsignal\fP \ %lu |
| The bitmap of pending signals, displayed as a decimal number. |
| Obsolete, because it does not provide information on real-time signals; use |
| .I /proc/[pid]/status |
| instead. |
| .TP |
| (32) \fIblocked\fP \ %lu |
| The bitmap of blocked signals, displayed as a decimal number. |
| Obsolete, because it does not provide information on real-time signals; use |
| .I /proc/[pid]/status |
| instead. |
| .TP |
| (33) \fIsigignore\fP \ %lu |
| The bitmap of ignored signals, displayed as a decimal number. |
| Obsolete, because it does not provide information on real-time signals; use |
| .I /proc/[pid]/status |
| instead. |
| .TP |
| (34) \fIsigcatch\fP \ %lu |
| The bitmap of caught signals, displayed as a decimal number. |
| Obsolete, because it does not provide information on real-time signals; use |
| .I /proc/[pid]/status |
| instead. |
| .TP |
| (35) \fIwchan\fP \ %lu \ [PT] |
| This is the "channel" in which the process is waiting. |
| It is the address of a location in the kernel where the process is sleeping. |
| The corresponding symbolic name can be found in |
| .IR /proc/[pid]/wchan . |
| .TP |
| (36) \fInswap\fP \ %lu |
| .\" nswap was added in 2.0 |
| Number of pages swapped (not maintained). |
| .TP |
| (37) \fIcnswap\fP \ %lu |
| .\" cnswap was added in 2.0 |
| Cumulative \fInswap\fP for child processes (not maintained). |
| .TP |
| (38) \fIexit_signal\fP \ %d \ (since Linux 2.1.22) |
| Signal to be sent to parent when we die. |
| .TP |
| (39) \fIprocessor\fP \ %d \ (since Linux 2.2.8) |
| CPU number last executed on. |
| .TP |
| (40) \fIrt_priority\fP \ %u \ (since Linux 2.5.19) |
| Real-time scheduling priority, a number in the range 1 to 99 for |
| processes scheduled under a real-time policy, |
| or 0, for non-real-time processes (see |
| .BR sched_setscheduler (2)). |
| .TP |
| (41) \fIpolicy\fP \ %u \ (since Linux 2.5.19) |
| Scheduling policy (see |
| .BR sched_setscheduler (2)). |
| Decode using the SCHED_* constants in |
| .IR linux/sched.h . |
| .IP |
| The format for this field was %lu before Linux 2.6.22. |
| .TP |
| (42) \fIdelayacct_blkio_ticks\fP \ %llu \ (since Linux 2.6.18) |
| Aggregated block I/O delays, measured in clock ticks (centiseconds). |
| .TP |
| (43) \fIguest_time\fP \ %lu \ (since Linux 2.6.24) |
| Guest time of the process (time spent running a virtual CPU |
| for a guest operating system), measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .TP |
| (44) \fIcguest_time\fP \ %ld \ (since Linux 2.6.24) |
| Guest time of the process's children, measured in clock ticks (divide by |
| .IR sysconf(_SC_CLK_TCK) ). |
| .TP |
| (45) \fIstart_data\fP \ %lu \ (since Linux 3.3) \ [PT] |
| .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
| Address above which program initialized and |
| uninitialized (BSS) data are placed. |
| .TP |
| (46) \fIend_data\fP \ %lu \ (since Linux 3.3) \ [PT] |
| .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
| Address below which program initialized and |
| uninitialized (BSS) data are placed. |
| .TP |
| (47) \fIstart_brk\fP \ %lu \ (since Linux 3.3) \ [PT] |
| .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
| Address above which program heap can be expanded with |
| .BR brk (2). |
| .TP |
| (48) \fIarg_start\fP \ %lu \ (since Linux 3.5) \ [PT] |
| .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
| Address above which program command-line arguments |
| .RI ( argv ) |
| are placed. |
| .TP |
| (49) \fIarg_end\fP \ %lu \ (since Linux 3.5) \ [PT] |
| .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
| Address below program command-line arguments |
| .RI ( argv ) |
| are placed. |
| .TP |
| (50) \fIenv_start\fP \ %lu \ (since Linux 3.5) \ [PT] |
| .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
| Address above which program environment is placed. |
| .TP |
| (51) \fIenv_end\fP \ %lu \ (since Linux 3.5) \ [PT] |
| .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
| Address below which program environment is placed. |
| .TP |
| (52) \fIexit_code\fP \ %d \ (since Linux 3.5) \ [PT] |
| .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
| The thread's exit status in the form reported by |
| .BR waitpid (2). |
| .RE |
| .TP |
| .I /proc/[pid]/statm |
| Provides information about memory usage, measured in pages. |
| The columns are: |
| .IP |
| .in +4n |
| .EX |
| size (1) total program size |
| (same as VmSize in \fI/proc/[pid]/status\fP) |
| resident (2) resident set size |
| (inaccurate; same as VmRSS in \fI/proc/[pid]/status\fP) |
| shared (3) number of resident shared pages |
| (i.e., backed by a file) |
| (inaccurate; same as RssFile+RssShmem in |
| \fI/proc/[pid]/status\fP) |
| text (4) text (code) |
| .\" (not including libs; broken, includes data segment) |
| lib (5) library (unused since Linux 2.6; always 0) |
| data (6) data + stack |
| .\" (including libs; broken, includes library text) |
| dt (7) dirty pages (unused since Linux 2.6; always 0) |
| .EE |
| .in |
| .IP |
| .\" See SPLIT_RSS_COUNTING in the kernel. |
| .\" Inaccuracy is bounded by TASK_RSS_EVENTS_THRESH. |
| Some of these values are inaccurate because |
| of a kernel-internal scalability optimization. |
| If accurate values are required, use |
| .I /proc/[pid]/smaps |
| or |
| .I /proc/[pid]/smaps_rollup |
| instead, which are much slower but provide accurate, detailed information. |
| .TP |
| .I /proc/[pid]/status |
| Provides much of the information in |
| .I /proc/[pid]/stat |
| and |
| .I /proc/[pid]/statm |
| in a format that's easier for humans to parse. |
| Here's an example: |
| .IP |
| .in +4n |
| .EX |
| .RB "$" " cat /proc/$$/status" |
| Name: bash |
| Umask: 0022 |
| State: S (sleeping) |
| Tgid: 17248 |
| Ngid: 0 |
| Pid: 17248 |
| PPid: 17200 |
| TracerPid: 0 |
| Uid: 1000 1000 1000 1000 |
| Gid: 100 100 100 100 |
| FDSize: 256 |
| Groups: 16 33 100 |
| NStgid: 17248 |
| NSpid: 17248 |
| NSpgid: 17248 |
| NSsid: 17200 |
| VmPeak: 131168 kB |
| VmSize: 131168 kB |
| VmLck: 0 kB |
| VmPin: 0 kB |
| VmHWM: 13484 kB |
| VmRSS: 13484 kB |
| RssAnon: 10264 kB |
| RssFile: 3220 kB |
| RssShmem: 0 kB |
| VmData: 10332 kB |
| VmStk: 136 kB |
| VmExe: 992 kB |
| VmLib: 2104 kB |
| VmPTE: 76 kB |
| VmPMD: 12 kB |
| VmSwap: 0 kB |
| HugetlbPages: 0 kB # 4.4 |
| CoreDumping: 0 # 4.15 |
| Threads: 1 |
| SigQ: 0/3067 |
| SigPnd: 0000000000000000 |
| ShdPnd: 0000000000000000 |
| SigBlk: 0000000000010000 |
| SigIgn: 0000000000384004 |
| SigCgt: 000000004b813efb |
| CapInh: 0000000000000000 |
| CapPrm: 0000000000000000 |
| CapEff: 0000000000000000 |
| CapBnd: ffffffffffffffff |
| CapAmb: 0000000000000000 |
| NoNewPrivs: 0 |
| Seccomp: 0 |
| Speculation_Store_Bypass: vulnerable |
| Cpus_allowed: 00000001 |
| Cpus_allowed_list: 0 |
| Mems_allowed: 1 |
| Mems_allowed_list: 0 |
| voluntary_ctxt_switches: 150 |
| nonvoluntary_ctxt_switches: 545 |
| .EE |
| .in |
| .IP |
| The fields are as follows: |
| .RS |
| .TP |
| .IR Name |
| Command run by this process. |
| Strings longer than |
| .B TASK_COMM_LEN |
| (16) characters (including the terminating null byte) are silently truncated. |
| .TP |
| .IR Umask |
| Process umask, expressed in octal with a leading zero; see |
| .BR umask (2). |
| (Since Linux 4.7.) |
| .TP |
| .IR State |
| Current state of the process. |
| One of |
| "R (running)", |
| "S (sleeping)", |
| "D (disk sleep)", |
| "T (stopped)", |
| "t (tracing stop)", |
| "Z (zombie)", |
| or |
| "X (dead)". |
| .TP |
| .IR Tgid |
| Thread group ID (i.e., Process ID). |
| .TP |
| .IR Ngid |
| NUMA group ID (0 if none; since Linux 3.13). |
| .TP |
| .IR Pid |
| Thread ID (see |
| .BR gettid (2)). |
| .TP |
| .IR PPid |
| PID of parent process. |
| .TP |
| .IR TracerPid |
| PID of process tracing this process (0 if not being traced). |
| .TP |
| .IR Uid ", " Gid |
| Real, effective, saved set, and filesystem UIDs (GIDs). |
| .TP |
| .IR FDSize |
| Number of file descriptor slots currently allocated. |
| .TP |
| .IR Groups |
| Supplementary group list. |
| .TP |
| .IR NStgid |
| Thread group ID (i.e., PID) in each of the PID namespaces of which |
| .I [pid] |
| is a member. |
| The leftmost entry shows the value with respect to the PID namespace |
| of the process that mounted this procfs (or the root namespace |
| if mounted by the kernel), |
| followed by the value in successively nested inner namespaces. |
| .\" commit e4bc33245124db69b74a6d853ac76c2976f472d5 |
| (Since Linux 4.1.) |
| .TP |
| .IR NSpid |
| Thread ID in each of the PID namespaces of which |
| .I [pid] |
| is a member. |
| The fields are ordered as for |
| .IR NStgid . |
| (Since Linux 4.1.) |
| .TP |
| .IR NSpgid |
| Process group ID in each of the PID namespaces of which |
| .I [pid] |
| is a member. |
| The fields are ordered as for |
| .IR NStgid . |
| (Since Linux 4.1.) |
| .TP |
| .IR NSsid |
| descendant namespace session ID hierarchy |
| Session ID in each of the PID namespaces of which |
| .I [pid] |
| is a member. |
| The fields are ordered as for |
| .IR NStgid . |
| (Since Linux 4.1.) |
| .TP |
| .IR VmPeak |
| Peak virtual memory size. |
| .TP |
| .IR VmSize |
| Virtual memory size. |
| .TP |
| .IR VmLck |
| Locked memory size (see |
| .BR mlock (2)). |
| .TP |
| .IR VmPin |
| Pinned memory size |
| .\" commit bc3e53f682d93df677dbd5006a404722b3adfe18 |
| (since Linux 3.2). |
| These are pages that can't be moved because something needs to |
| directly access physical memory. |
| .TP |
| .IR VmHWM |
| Peak resident set size ("high water mark"). |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR VmRSS |
| Resident set size. |
| Note that the value here is the sum of |
| .IR RssAnon , |
| .IR RssFile , |
| and |
| .IR RssShmem . |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR RssAnon |
| Size of resident anonymous memory. |
| .\" commit bf9683d6990589390b5178dafe8fd06808869293 |
| (since Linux 4.5). |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR RssFile |
| Size of resident file mappings. |
| .\" commit bf9683d6990589390b5178dafe8fd06808869293 |
| (since Linux 4.5). |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR RssShmem |
| Size of resident shared memory (includes System V shared memory, |
| mappings from |
| .BR tmpfs (5), |
| and shared anonymous mappings). |
| .\" commit bf9683d6990589390b5178dafe8fd06808869293 |
| (since Linux 4.5). |
| .TP |
| .IR VmData ", " VmStk ", " VmExe |
| Size of data, stack, and text segments. |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR VmLib |
| Shared library code size. |
| .TP |
| .IR VmPTE |
| Page table entries size (since Linux 2.6.10). |
| .TP |
| .IR VmPMD |
| .\" commit dc6c9a35b66b520cf67e05d8ca60ebecad3b0479 |
| Size of second-level page tables (added in Linux 4.0; removed in Linux 4.15). |
| .TP |
| .IR VmSwap |
| .\" commit b084d4353ff99d824d3bc5a5c2c22c70b1fba722 |
| Swapped-out virtual memory size by anonymous private pages; |
| shmem swap usage is not included (since Linux 2.6.34). |
| This value is inaccurate; see |
| .I /proc/[pid]/statm |
| above. |
| .TP |
| .IR HugetlbPages |
| Size of hugetlb memory portions |
| .\" commit 5d317b2b6536592a9b51fe65faed43d65ca9158e |
| (since Linux 4.4). |
| .TP |
| .IR CoreDumping |
| Contains the value 1 if the process is currently dumping core, |
| and 0 if it is not |
| .\" commit c643401218be0f4ab3522e0c0a63016596d6e9ca |
| (since Linux 4.15). |
| This information can be used by a monitoring process to avoid killing |
| a process that is currently dumping core, |
| which could result in a corrupted core dump file. |
| .TP |
| .IR Threads |
| Number of threads in process containing this thread. |
| .TP |
| .IR SigQ |
| This field contains two slash-separated numbers that relate to |
| queued signals for the real user ID of this process. |
| The first of these is the number of currently queued |
| signals for this real user ID, and the second is the |
| resource limit on the number of queued signals for this process |
| (see the description of |
| .BR RLIMIT_SIGPENDING |
| in |
| .BR getrlimit (2)). |
| .TP |
| .IR SigPnd ", " ShdPnd |
| Mask (expressed in hexadecimal) |
| of signals pending for thread and for process as a whole (see |
| .BR pthreads (7) |
| and |
| .BR signal (7)). |
| .TP |
| .IR SigBlk ", " SigIgn ", " SigCgt |
| Masks (expressed in hexadecimal) |
| indicating signals being blocked, ignored, and caught (see |
| .BR signal (7)). |
| .TP |
| .IR CapInh ", " CapPrm ", " CapEff |
| Masks (expressed in hexadecimal) |
| of capabilities enabled in inheritable, permitted, and effective sets |
| (see |
| .BR capabilities (7)). |
| .TP |
| .IR CapBnd |
| Capability bounding set, expressed in hexadecimal |
| (since Linux 2.6.26, see |
| .BR capabilities (7)). |
| .TP |
| .IR CapAmb |
| Ambient capability set, expressed in hexadecimal |
| (since Linux 4.3, see |
| .BR capabilities (7)). |
| .TP |
| .IR NoNewPrivs |
| .\" commit af884cd4a5ae62fcf5e321fecf0ec1014730353d |
| Value of the |
| .I no_new_privs |
| bit |
| (since Linux 4.10, see |
| .BR prctl (2)). |
| .TP |
| .IR Seccomp |
| .\" commit 2f4b3bf6b2318cfaa177ec5a802f4d8d6afbd816 |
| Seccomp mode of the process |
| (since Linux 3.8, see |
| .BR seccomp (2)). |
| 0 means |
| .BR SECCOMP_MODE_DISABLED ; |
| 1 means |
| .BR SECCOMP_MODE_STRICT ; |
| 2 means |
| .BR SECCOMP_MODE_FILTER . |
| This field is provided only if the kernel was built with the |
| .BR CONFIG_SECCOMP |
| kernel configuration option enabled. |
| .TP |
| .IR Speculation_Store_Bypass |
| .\" commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64 |
| Speculation flaw mitigation state |
| (since Linux 4.17, see |
| .BR prctl (2)). |
| .TP |
| .IR Cpus_allowed |
| Hexadecimal mask of CPUs on which this process may run |
| (since Linux 2.6.24, see |
| .BR cpuset (7)). |
| .TP |
| .IR Cpus_allowed_list |
| Same as previous, but in "list format" |
| (since Linux 2.6.26, see |
| .BR cpuset (7)). |
| .TP |
| .IR Mems_allowed |
| Mask of memory nodes allowed to this process |
| (since Linux 2.6.24, see |
| .BR cpuset (7)). |
| .TP |
| .IR Mems_allowed_list |
| Same as previous, but in "list format" |
| (since Linux 2.6.26, see |
| .BR cpuset (7)). |
| .TP |
| .IR voluntary_ctxt_switches ", " nonvoluntary_ctxt_switches |
| Number of voluntary and involuntary context switches (since Linux 2.6.23). |
| .RE |
| .TP |
| .IR /proc/[pid]/syscall " (since Linux 2.6.27)" |
| .\" commit ebcb67341fee34061430f3367f2e507e52ee051b |
| This file exposes the system call number and argument registers for the |
| system call currently being executed by the process, |
| followed by the values of the stack pointer and program counter registers. |
| The values of all six argument registers are exposed, |
| although most system calls use fewer registers. |
| .IP |
| If the process is blocked, but not in a system call, |
| then the file displays \-1 in place of the system call number, |
| followed by just the values of the stack pointer and program counter. |
| If process is not blocked, then the file contains just the string "running". |
| .IP |
| This file is present only if the kernel was configured with |
| .BR CONFIG_HAVE_ARCH_TRACEHOOK . |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_ATTACH_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[pid]/task " (since Linux 2.6.0)" |
| .\" Precisely: Linux 2.6.0-test6 |
| This is a directory that contains one subdirectory |
| for each thread in the process. |
| The name of each subdirectory is the numerical thread ID |
| .RI ( [tid] ) |
| of the thread (see |
| .BR gettid (2)). |
| .IP |
| Within each of these subdirectories, there is a set of |
| files with the same names and contents as under the |
| .I /proc/[pid] |
| directories. |
| For attributes that are shared by all threads, the contents for |
| each of the files under the |
| .I task/[tid] |
| subdirectories will be the same as in the corresponding |
| file in the parent |
| .I /proc/[pid] |
| directory |
| (e.g., in a multithreaded process, all of the |
| .I task/[tid]/cwd |
| files will have the same value as the |
| .I /proc/[pid]/cwd |
| file in the parent directory, since all of the threads in a process |
| share a working directory). |
| For attributes that are distinct for each thread, |
| the corresponding files under |
| .I task/[tid] |
| may have different values (e.g., various fields in each of the |
| .I task/[tid]/status |
| files may be different for each thread), |
| .\" in particular: "children" :/ |
| or they might not exist in |
| .I /proc/[pid] |
| at all. |
| .IP |
| .\" The following was still true as at kernel 2.6.13 |
| In a multithreaded process, the contents of the |
| .I /proc/[pid]/task |
| directory are not available if the main thread has already terminated |
| (typically by calling |
| .BR pthread_exit (3)). |
| .TP |
| .IR /proc/[pid]/task/[tid]/children " (since Linux 3.5)" |
| .\" commit 818411616baf46ceba0cff6f05af3a9b294734f7 |
| A space-separated list of child tasks of this task. |
| Each child task is represented by its TID. |
| .IP |
| .\" see comments in get_children_pid() in fs/proc/array.c |
| This option is intended for use by the checkpoint-restore (CRIU) system, |
| and reliably provides a list of children only if all of the child processes |
| are stopped or frozen. |
| It does not work properly if children of the target task exit while |
| the file is being read! |
| Exiting children may cause non-exiting children to be omitted from the list. |
| This makes this interface even more unreliable than classic PID-based |
| approaches if the inspected task and its children aren't frozen, |
| and most code should probably not use this interface. |
| .IP |
| Until Linux 4.2, the presence of this file was governed by the |
| .B CONFIG_CHECKPOINT_RESTORE |
| kernel configuration option. |
| Since Linux 4.2, |
| .\" commit 2e13ba54a2682eea24918b87ad3edf70c2cf085b |
| it is governed by the |
| .B CONFIG_PROC_CHILDREN |
| option. |
| .TP |
| .IR /proc/[pid]/timers " (since Linux 3.10)" |
| .\" commit 5ed67f05f66c41e39880a6d61358438a25f9fee5 |
| .\" commit 48f6a7a511ef8823fdff39afee0320092d43a8a0 |
| A list of the POSIX timers for this process. |
| Each timer is listed with a line that starts with the string "ID:". |
| For example: |
| .IP |
| .in +4n |
| .EX |
| ID: 1 |
| signal: 60/00007fff86e452a8 |
| notify: signal/pid.2634 |
| ClockID: 0 |
| ID: 0 |
| signal: 60/00007fff86e452a8 |
| notify: signal/pid.2634 |
| ClockID: 1 |
| .EE |
| .in |
| .IP |
| The lines shown for each timer have the following meanings: |
| .RS |
| .TP |
| .I ID |
| The ID for this timer. |
| This is not the same as the timer ID returned by |
| .BR timer_create (2); |
| rather, it is the same kernel-internal ID that is available via the |
| .I si_timerid |
| field of the |
| .IR siginfo_t |
| structure (see |
| .BR sigaction (2)). |
| .TP |
| .I signal |
| This is the signal number that this timer uses to deliver notifications |
| followed by a slash, and then the |
| .I sigev_value |
| value supplied to the signal handler. |
| Valid only for timers that notify via a signal. |
| .TP |
| .I notify |
| The part before the slash specifies the mechanism |
| that this timer uses to deliver notifications, |
| and is one of "thread", "signal", or "none". |
| Immediately following the slash is either the string "tid" for timers |
| with |
| .B SIGEV_THREAD_ID |
| notification, or "pid" for timers that notify by other mechanisms. |
| Following the "." is the PID of the process |
| (or the kernel thread ID of the thread) that will be delivered |
| a signal if the timer delivers notifications via a signal. |
| .TP |
| .I ClockID |
| This field identifies the clock that the timer uses for measuring time. |
| For most clocks, this is a number that matches one of the user-space |
| .BR CLOCK_* |
| constants exposed via |
| .IR <time.h> . |
| .B CLOCK_PROCESS_CPUTIME_ID |
| timers display with a value of \-6 |
| in this field. |
| .B CLOCK_THREAD_CPUTIME_ID |
| timers display with a value of \-2 |
| in this field. |
| .RE |
| .IP |
| This file is available only when the kernel was configured with |
| .BR CONFIG_CHECKPOINT_RESTORE . |
| .TP |
| .IR /proc/[pid]/timerslack_ns " (since Linux 4.6)" |
| .\" commit da8b44d5a9f8bf26da637b7336508ca534d6b319 |
| .\" commit 5de23d435e88996b1efe0e2cebe242074ce67c9e |
| This file exposes the process's "current" timer slack value, |
| expressed in nanoseconds. |
| The file is writable, |
| allowing the process's timer slack value to be changed. |
| Writing 0 to this file resets the "current" timer slack to the |
| "default" timer slack value. |
| For further details, see the discussion of |
| .BR PR_SET_TIMERSLACK |
| in |
| .BR prctl (2). |
| .IP |
| Initially, |
| permission to access this file was governed by a ptrace access mode |
| .B PTRACE_MODE_ATTACH_FSCREDS |
| check (see |
| .BR ptrace (2)). |
| However, this was subsequently deemed too strict a requirement |
| (and had the side effect that requiring a process to have the |
| .B CAP_SYS_PTRACE |
| capability would also allow it to view and change any process's memory). |
| Therefore, since Linux 4.9, |
| .\" commit 7abbaf94049914f074306d960b0f968ffe52e59f |
| only the (weaker) |
| .B CAP_SYS_NICE |
| capability is required to access this file. |
| .TP |
| .IR /proc/[pid]/uid_map ", " /proc/[pid]/gid_map " (since Linux 3.5)" |
| See |
| .BR user_namespaces (7). |
| .TP |
| .IR /proc/[pid]/wchan " (since Linux 2.6.0)" |
| The symbolic name corresponding to the location |
| in the kernel where the process is sleeping. |
| .IP |
| Permission to access this file is governed by a ptrace access mode |
| .B PTRACE_MODE_READ_FSCREDS |
| check; see |
| .BR ptrace (2). |
| .TP |
| .IR /proc/[tid] |
| There is a numerical subdirectory for each running thread |
| that is not a thread group leader |
| (i.e., a thread whose thread ID is not the same as its process ID); |
| the subdirectory is named by the thread ID. |
| Each one of these subdirectories contains files and subdirectories |
| exposing information about the thread with the thread ID |
| .IR tid . |
| The contents of these directories are the same as the corresponding |
| .IR /proc/[pid]/task/[tid] |
| directories. |
| .IP |
| The |
| .I /proc/[tid] |
| subdirectories are |
| .I not |
| visible when iterating through |
| .I /proc |
| with |
| .BR getdents (2) |
| (and thus are |
| .I not |
| visible when one uses |
| .BR ls (1) |
| to view the contents of |
| .IR /proc ). |
| However, the pathnames of these directories are visible to |
| (i.e., usable as arguments in) |
| system calls that operate on pathnames. |
| .TP |
| .I /proc/apm |
| Advanced power management version and battery information when |
| .B CONFIG_APM |
| is defined at kernel compilation time. |
| .TP |
| .I /proc/buddyinfo |
| This file contains information which is used for diagnosing memory |
| fragmentation issues. |
| Each line starts with the identification of the node and the name |
| of the zone which together identify a memory region. |
| This is then |
| followed by the count of available chunks of a certain order in |
| which these zones are split. |
| The size in bytes of a certain order is given by the formula: |
| .IP |
| (2^order)\ *\ PAGE_SIZE |
| .IP |
| The binary buddy allocator algorithm inside the kernel will split |
| one chunk into two chunks of a smaller order (thus with half the |
| size) or combine two contiguous chunks into one larger chunk of |
| a higher order (thus with double the size) to satisfy allocation |
| requests and to counter memory fragmentation. |
| The order matches the column number, when starting to count at zero. |
| .IP |
| For example on an x86-64 system: |
| .RS -12 |
| .EX |
| Node 0, zone DMA 1 1 1 0 2 1 1 0 1 1 3 |
| Node 0, zone DMA32 65 47 4 81 52 28 13 10 5 1 404 |
| Node 0, zone Normal 216 55 189 101 84 38 37 27 5 3 587 |
| .EE |
| .RE |
| .IP |
| In this example, there is one node containing three zones and there |
| are 11 different chunk sizes. |
| If the page size is 4 kilobytes, then the first zone called |
| .I DMA |
| (on x86 the first 16 megabyte of memory) has 1 chunk of 4 kilobytes |
| (order 0) available and has 3 chunks of 4 megabytes (order 10) available. |
| .IP |
| If the memory is heavily fragmented, the counters for higher |
| order chunks will be zero and allocation of large contiguous areas |
| will fail. |
| .IP |
| Further information about the zones can be found in |
| .IR /proc/zoneinfo . |
| .TP |
| .I /proc/bus |
| Contains subdirectories for installed busses. |
| .TP |
| .I /proc/bus/pccard |
| Subdirectory for PCMCIA devices when |
| .B CONFIG_PCMCIA |
| is set at kernel compilation time. |
| .TP |
| .I /proc/bus/pccard/drivers |
| .TP |
| .I /proc/bus/pci |
| Contains various bus subdirectories and pseudo-files containing |
| information about PCI busses, installed devices, and device |
| drivers. |
| Some of these files are not ASCII. |
| .TP |
| .I /proc/bus/pci/devices |
| Information about PCI devices. |
| They may be accessed through |
| .BR lspci (8) |
| and |
| .BR setpci (8). |
| .TP |
| .IR /proc/cgroups " (since Linux 2.6.24)" |
| See |
| .BR cgroups (7). |
| .TP |
| .I /proc/cmdline |
| Arguments passed to the Linux kernel at boot time. |
| Often done via a boot manager such as |
| .BR lilo (8) |
| or |
| .BR grub (8). |
| .TP |
| .IR /proc/config.gz " (since Linux 2.6)" |
| This file exposes the configuration options that were used |
| to build the currently running kernel, |
| in the same format as they would be shown in the |
| .I .config |
| file that resulted when configuring the kernel (using |
| .IR "make xconfig" , |
| .IR "make config" , |
| or similar). |
| The file contents are compressed; view or search them using |
| .BR zcat (1) |
| and |
| .BR zgrep (1). |
| As long as no changes have been made to the following file, |
| the contents of |
| .I /proc/config.gz |
| are the same as those provided by: |
| .IP |
| .in +4n |
| .EX |
| cat /lib/modules/$(uname \-r)/build/.config |
| .EE |
| .in |
| .IP |
| .I /proc/config.gz |
| is provided only if the kernel is configured with |
| .BR CONFIG_IKCONFIG_PROC . |
| .TP |
| .I /proc/crypto |
| A list of the ciphers provided by the kernel crypto API. |
| For details, see the kernel |
| .I "Linux Kernel Crypto API" |
| documentation available under the kernel source directory |
| .I Documentation/crypto/ |
| .\" commit 3b72c814a8e8cd638e1ba0da4dfce501e9dff5af |
| (or |
| .I Documentation/DocBook |
| before 4.10; |
| the documentation can be built using a command such as |
| .IR "make htmldocs" |
| in the root directory of the kernel source tree). |
| .TP |
| .I /proc/cpuinfo |
| This is a collection of CPU and system architecture dependent items, |
| for each supported architecture a different list. |
| Two common entries are \fIprocessor\fP which gives CPU number and |
| \fIbogomips\fP; a system constant that is calculated |
| during kernel initialization. |
| SMP machines have information for |
| each CPU. |
| The |
| .BR lscpu (1) |
| command gathers its information from this file. |
| .TP |
| .I /proc/devices |
| Text listing of major numbers and device groups. |
| This can be used by MAKEDEV scripts for consistency with the kernel. |
| .TP |
| .IR /proc/diskstats " (since Linux 2.5.69)" |
| This file contains disk I/O statistics for each disk device. |
| See the Linux kernel source file |
| .I Documentation/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 filesystems which are supported by the kernel, |
| namely filesystems which were compiled into the kernel or whose kernel |
| modules are currently loaded. |
| (See also |
| .BR filesystems (5).) |
| If a filesystem is marked with "nodev", |
| this means that it does not require a block device to be mounted |
| (e.g., virtual filesystem, network filesystem). |
| .IP |
| Incidentally, this file may be used by |
| .BR mount (8) |
| when no filesystem is specified and it didn't manage to determine the |
| filesystem type. |
| Then filesystems contained in this file are tried |
| (excepted those that are marked with "nodev"). |
| .TP |
| .I /proc/fs |
| .\" FIXME Much more needs to be said about /proc/fs |
| .\" |
| Contains subdirectories that in turn contain files |
| with information about (certain) mounted filesystems. |
| .TP |
| .I /proc/ide |
| This directory |
| exists on systems with the IDE bus. |
| There are directories for each IDE channel and attached device. |
| Files include: |
| .IP |
| .in +4n |
| .EX |
| cache buffer size in KB |
| capacity number of sectors |
| driver driver version |
| geometry physical and logical geometry |
| identify in hexadecimal |
| media media type |
| model manufacturer\(aqs model number |
| settings drive settings |
| smart_thresholds IDE disk management thresholds (in hex) |
| smart_values IDE disk management values (in hex) |
| .EE |
| .in |
| .IP |
| The |
| .BR hdparm (8) |
| utility provides access to this information in a friendly format. |
| .TP |
| .I /proc/interrupts |
| This is used to record the number of interrupts per CPU per IO device. |
| Since Linux 2.6.24, |
| for the i386 and x86-64 architectures, at least, this also includes |
| interrupts internal to the system (that is, not associated with a device |
| as such), such as NMI (nonmaskable interrupt), LOC (local timer interrupt), |
| and for SMP systems, TLB (TLB flush interrupt), RES (rescheduling |
| interrupt), CAL (remote function call interrupt), and possibly others. |
| Very easy to read formatting, done in ASCII. |
| .TP |
| .I /proc/iomem |
| I/O memory map in Linux 2.4. |
| .TP |
| .I /proc/ioports |
| This is a list of currently registered Input-Output port regions that |
| are in use. |
| .TP |
| .IR /proc/kallsyms " (since Linux 2.5.71)" |
| This holds the kernel exported symbol definitions used by the |
| .BR modules (X) |
| tools to dynamically link and bind loadable modules. |
| In Linux 2.5.47 and earlier, a similar file with slightly different syntax |
| was named |
| .IR ksyms . |
| .TP |
| .I /proc/kcore |
| This file represents the physical memory of the system and is stored |
| in the ELF core file format. |
| With this pseudo-file, and an unstripped |
| kernel |
| .RI ( /usr/src/linux/vmlinux ) |
| binary, GDB can be used to |
| examine the current state of any kernel data structures. |
| .IP |
| The total length of the file is the size of physical memory (RAM) plus |
| 4\ KiB. |
| .TP |
| .IR /proc/keys " (since Linux 2.6.10)" |
| See |
| .BR keyrings (7). |
| .TP |
| .IR /proc/key\-users " (since Linux 2.6.10)" |
| See |
| .BR keyrings (7). |
| .TP |
| .I /proc/kmsg |
| This file can be used instead of the |
| .BR syslog (2) |
| system call to read kernel messages. |
| A process must have superuser |
| privileges to read this file, and only one process should read this |
| file. |
| This file should not be read if a syslog process is running |
| which uses the |
| .BR syslog (2) |
| system call facility to log kernel messages. |
| .IP |
| Information in this file is retrieved with the |
| .BR dmesg (1) |
| program. |
| .TP |
| .IR /proc/kpagecgroup " (since Linux 4.3)" |
| .\" commit 80ae2fdceba8313b0433f899bdd9c6c463291a17 |
| This file contains a 64-bit inode number of |
| the memory cgroup each page is charged to, |
| indexed by page frame number (see the discussion of |
| .IR /proc/[pid]/pagemap ). |
| .IP |
| The |
| .IR /proc/kpagecgroup |
| file is present only if the |
| .B CONFIG_MEMCG |
| kernel configuration option is enabled. |
| .TP |
| .IR /proc/kpagecount " (since Linux 2.6.25)" |
| This file contains a 64-bit count of the number of |
| times each physical page frame is mapped, |
| indexed by page frame number (see the discussion of |
| .IR /proc/[pid]/pagemap ). |
| .IP |
| The |
| .IR /proc/kpagecount |
| file is present only if the |
| .B CONFIG_PROC_PAGE_MONITOR |
| kernel configuration option is enabled. |
| .TP |
| .IR /proc/kpageflags " (since Linux 2.6.25)" |
| This file contains 64-bit masks corresponding to each physical page frame; |
| it is indexed by page frame number (see the discussion of |
| .IR /proc/[pid]/pagemap ). |
| The bits are as follows: |
| .IP |
| 0 - KPF_LOCKED |
| 1 - KPF_ERROR |
| 2 - KPF_REFERENCED |
| 3 - KPF_UPTODATE |
| 4 - KPF_DIRTY |
| 5 - KPF_LRU |
| 6 - KPF_ACTIVE |
| 7 - KPF_SLAB |
| 8 - KPF_WRITEBACK |
| 9 - KPF_RECLAIM |
| 10 - KPF_BUDDY |
| 11 - KPF_MMAP (since Linux 2.6.31) |
| 12 - KPF_ANON (since Linux 2.6.31) |
| 13 - KPF_SWAPCACHE (since Linux 2.6.31) |
| 14 - KPF_SWAPBACKED (since Linux 2.6.31) |
| 15 - KPF_COMPOUND_HEAD (since Linux 2.6.31) |
| 16 - KPF_COMPOUND_TAIL (since Linux 2.6.31) |
| 17 - KPF_HUGE (since Linux 2.6.31) |
| 18 - KPF_UNEVICTABLE (since Linux 2.6.31) |
| 19 - KPF_HWPOISON (since Linux 2.6.31) |
| 20 - KPF_NOPAGE (since Linux 2.6.31) |
| 21 - KPF_KSM (since Linux 2.6.32) |
| 22 - KPF_THP (since Linux 3.4) |
| 23 - KPF_BALLOON (since Linux 3.18) |
| .\" KPF_BALLOON: commit 09316c09dde33aae14f34489d9e3d243ec0d5938 |
| 24 - KPF_ZERO_PAGE (since Linux 4.0) |
| .\" KPF_ZERO_PAGE: commit 56873f43abdcd574b25105867a990f067747b2f4 |
| 25 - KPF_IDLE (since Linux 4.3) |
| .\" KPF_IDLE: commit f074a8f49eb87cde95ac9d040ad5e7ea4f029738 |
| .IP |
| For further details on the meanings of these bits, |
| see the kernel source file |
| .IR Documentation/admin\-guide/mm/pagemap.rst . |
| Before kernel 2.6.29, |
| .\" commit ad3bdefe877afb47480418fdb05ecd42842de65e |
| .\" commit e07a4b9217d1e97d2f3a62b6b070efdc61212110 |
| .BR KPF_WRITEBACK , |
| .BR KPF_RECLAIM , |
| .BR KPF_BUDDY , |
| and |
| .BR KPF_LOCKED |
| did not report correctly. |
| .IP |
| The |
| .IR /proc/kpageflags |
| file is present only if the |
| .B CONFIG_PROC_PAGE_MONITOR |
| kernel configuration option is enabled. |
| .TP |
| .IR /proc/ksyms " (Linux 1.1.23\(en2.5.47)" |
| See |
| .IR /proc/kallsyms . |
| .TP |
| .I /proc/loadavg |
| The first three fields in this file are load average figures |
| giving the number of jobs in the run queue (state R) |
| or waiting for disk I/O (state D) averaged over 1, 5, and 15 minutes. |
| They are the same as the load average numbers given by |
| .BR uptime (1) |
| and other programs. |
| The fourth field consists of two numbers separated by a slash (/). |
| The first of these is the number of currently runnable kernel |
| scheduling entities (processes, threads). |
| The value after the slash is the number of kernel scheduling entities |
| that currently exist on the system. |
| The fifth field is the PID of the process that was most |
| recently created on the system. |
| .TP |
| .I /proc/locks |
| This file shows current file locks |
| .RB ( flock "(2) and " fcntl (2)) |
| and leases |
| .RB ( fcntl (2)). |
| .IP |
| An example of the content shown in this file is the following: |
| .IP |
| .in +4n |
| .EX |
| 1: POSIX ADVISORY READ 5433 08:01:7864448 128 128 |
| 2: FLOCK ADVISORY WRITE 2001 08:01:7864554 0 EOF |
| 3: FLOCK ADVISORY WRITE 1568 00:2f:32388 0 EOF |
| 4: POSIX ADVISORY WRITE 699 00:16:28457 0 EOF |
| 5: POSIX ADVISORY WRITE 764 00:16:21448 0 0 |
| 6: POSIX ADVISORY READ 3548 08:01:7867240 1 1 |
| 7: POSIX ADVISORY READ 3548 08:01:7865567 1826 2335 |
| 8: OFDLCK ADVISORY WRITE \-1 08:01:8713209 128 191 |
| .EE |
| .in |
| .IP |
| The fields shown in each line are as follows: |
| .RS |
| .IP (1) 4 |
| The ordinal position of the lock in the list. |
| .IP (2) |
| The lock type. |
| Values that may appear here include: |
| .RS |
| .TP |
| .B FLOCK |
| This is a BSD file lock created using |
| .BR flock (2). |
| .TP |
| .B OFDLCK |
| This is an open file description (OFD) lock created using |
| .BR fcntl (2). |
| .TP |
| .B POSIX |
| This is a POSIX byte-range lock created using |
| .BR fcntl (2). |
| .RE |
| .IP (3) |
| Among the strings that can appear here are the following: |
| .RS |
| .TP |
| .B ADVISORY |
| This is an advisory lock. |
| .TP |
| .B MANDATORY |
| This is a mandatory lock. |
| .RE |
| .IP (4) |
| The type of lock. |
| Values that can appear here are: |
| .RS |
| .TP |
| .B READ |
| This is a POSIX or OFD read lock, or a BSD shared lock. |
| .TP |
| .B WRITE |
| This is a POSIX or OFD write lock, or a BSD exclusive lock. |
| .RE |
| .IP (5) |
| The PID of the process that owns the lock. |
| .IP |
| Because OFD locks are not owned by a single process |
| (since multiple processes may have file descriptors that |
| refer to the same open file description), |
| the value \-1 is displayed in this field for OFD locks. |
| (Before kernel 4.14, |
| .\" commit 9d5b86ac13c573795525ecac6ed2db39ab23e2a8 |
| a bug meant that the PID of the process that |
| initially acquired the lock was displayed instead of the value \-1.) |
| .IP (6) |
| Three colon-separated subfields that identify the major and minor device |
| ID of the device containing the filesystem where the locked file resides, |
| followed by the inode number of the locked file. |
| .IP (7) |
| The byte offset of the first byte of the lock. |
| For BSD locks, this value is always 0. |
| .IP (8) |
| The byte offset of the last byte of the lock. |
| .B EOF |
| in this field means that the lock extends to the end of the file. |
| For BSD locks, the value shown is always |
| .IR EOF . |
| .RE |
| .IP |
| Since Linux 4.9, |
| .\" commit d67fd44f697dff293d7cdc29af929241b669affe |
| the list of locks shown in |
| .I /proc/locks |
| is filtered to show just the locks for the processes in the PID |
| namespace (see |
| .BR pid_namespaces (7)) |
| for which the |
| .I /proc |
| filesystem was mounted. |
| (In the initial PID namespace, |
| there is no filtering of the records shown in this file.) |
| .IP |
| The |
| .BR lslocks (8) |
| command provides a bit more information about each lock. |
| .TP |
| .IR /proc/malloc " (only up to and including Linux 2.2)" |
| .\" It looks like this only ever did something back in 1.0 days |
| This file is present only if |
| .B CONFIG_DEBUG_MALLOC |
| was defined during compilation. |
| .TP |
| .I /proc/meminfo |
| This file reports statistics about memory usage on the system. |
| It is used by |
| .BR free (1) |
| to report the amount of free and used memory (both physical and swap) |
| on the system as well as the shared memory and buffers used by the |
| kernel. |
| Each line of the file consists of a parameter name, followed by a colon, |
| the value of the parameter, and an option unit of measurement (e.g., "kB"). |
| The list below describes the parameter names and |
| the format specifier required to read the field value. |
| Except as noted below, |
| all of the fields have been present since at least Linux 2.6.0. |
| Some fields are displayed only if the kernel was configured |
| with various options; those dependencies are noted in the list. |
| .RS |
| .TP |
| .IR MemTotal " %lu" |
| Total usable RAM (i.e., physical RAM minus a few reserved |
| bits and the kernel binary code). |
| .TP |
| .IR MemFree " %lu" |
| The sum of |
| .IR LowFree + HighFree . |
| .TP |
| .IR MemAvailable " %lu (since Linux 3.14)" |
| An estimate of how much memory is available for starting new |
| applications, without swapping. |
| .TP |
| .IR Buffers " %lu" |
| Relatively temporary storage for raw disk blocks that |
| shouldn't get tremendously large (20 MB or so). |
| .TP |
| .IR Cached " %lu" |
| In-memory cache for files read from the disk (the page cache). |
| Doesn't include |
| .IR SwapCached . |
| .TP |
| .IR SwapCached " %lu" |
| Memory that once was swapped out, is swapped back in but |
| still also is in the swap file. |
| (If memory pressure is high, these pages |
| don't need to be swapped out again because they are already |
| in the swap file. |
| This saves I/O.) |
| .TP |
| .IR Active " %lu" |
| Memory that has been used more recently and usually not |
| reclaimed unless absolutely necessary. |
| .TP |
| .IR Inactive " %lu" |
| Memory which has been less recently used. |
| It is more eligible to be reclaimed for other purposes. |
| .TP |
| .IR Active(anon) " %lu (since Linux 2.6.28)" |
| [To be documented.] |
| .TP |
| .IR Inactive(anon) " %lu (since Linux 2.6.28)" |
| [To be documented.] |
| .TP |
| .IR Active(file) " %lu (since Linux 2.6.28)" |
| [To be documented.] |
| .TP |
| .IR Inactive(file) " %lu (since Linux 2.6.28)" |
| [To be documented.] |
| .TP |
| .IR Unevictable " %lu (since Linux 2.6.28)" |
| (From Linux 2.6.28 to 2.6.30, |
| \fBCONFIG_UNEVICTABLE_LRU\fP was required.) |
| [To be documented.] |
| .TP |
| .IR Mlocked " %lu (since Linux 2.6.28)" |
| (From Linux 2.6.28 to 2.6.30, |
| \fBCONFIG_UNEVICTABLE_LRU\fP was required.) |
| [To be documented.] |
| .TP |
| .IR HighTotal " %lu" |
| (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
| Total amount of highmem. |
| Highmem is all memory above \(ti860 MB of physical memory. |
| Highmem areas are for use by user-space programs, |
| or for the page cache. |
| The kernel must use tricks to access |
| this memory, making it slower to access than lowmem. |
| .TP |
| .IR HighFree " %lu" |
| (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
| Amount of free highmem. |
| .TP |
| .IR LowTotal " %lu" |
| (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
| Total amount of lowmem. |
| Lowmem is memory which can be used for everything that |
| highmem can be used for, but it is also available for the |
| kernel's use for its own data structures. |
| Among many other things, |
| it is where everything from |
| .I Slab |
| is allocated. |
| Bad things happen when you're out of lowmem. |
| .TP |
| .IR LowFree " %lu" |
| (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
| Amount of free lowmem. |
| .TP |
| .IR MmapCopy " %lu (since Linux 2.6.29)" |
| .RB ( CONFIG_MMU |
| is required.) |
| [To be documented.] |
| .TP |
| .IR SwapTotal " %lu" |
| Total amount of swap space available. |
| .TP |
| .IR SwapFree " %lu" |
| Amount of swap space that is currently unused. |
| .TP |
| .IR Dirty " %lu" |
| Memory which is waiting to get written back to the disk. |
| .TP |
| .IR Writeback " %lu" |
| Memory which is actively being written back to the disk. |
| .TP |
| .IR AnonPages " %lu (since Linux 2.6.18)" |
| Non-file backed pages mapped into user-space page tables. |
| .TP |
| .IR Mapped " %lu" |
| Files which have been mapped into memory (with |
| .BR mmap (2)), |
| such as libraries. |
| .TP |
| .IR Shmem " %lu (since Linux 2.6.32)" |
| Amount of memory consumed in |
| .BR tmpfs (5) |
| filesystems. |
| .TP |
| .IR KReclaimable " %lu (since Linux 4.20)" |
| Kernel allocations that the kernel will attempt to reclaim |
| under memory pressure. |
| Includes |
| .I SReclaimable |
| (below), and other direct allocations with a shrinker. |
| .TP |
| .IR Slab " %lu" |
| In-kernel data structures cache. |
| (See |
| .BR slabinfo (5).) |
| .TP |
| .IR SReclaimable " %lu (since Linux 2.6.19)" |
| Part of |
| .IR Slab , |
| that might be reclaimed, such as caches. |
| .TP |
| .IR SUnreclaim " %lu (since Linux 2.6.19)" |
| Part of |
| .IR Slab , |
| that cannot be reclaimed on memory pressure. |
| .TP |
| .IR KernelStack " %lu (since Linux 2.6.32)" |
| Amount of memory allocated to kernel stacks. |
| .TP |
| .IR PageTables " %lu (since Linux 2.6.18)" |
| Amount of memory dedicated to the lowest level of page tables. |
| .TP |
| .IR Quicklists " %lu (since Linux 2.6.27)" |
| (\fBCONFIG_QUICKLIST\fP is required.) |
| [To be documented.] |
| .TP |
| .IR NFS_Unstable " %lu (since Linux 2.6.18)" |
| NFS pages sent to the server, but not yet committed to stable storage. |
| .TP |
| .IR Bounce " %lu (since Linux 2.6.18)" |
| Memory used for block device "bounce buffers". |
| .TP |
| .IR WritebackTmp " %lu (since Linux 2.6.26)" |
| Memory used by FUSE for temporary writeback buffers. |
| .TP |
| .IR CommitLimit " %lu (since Linux 2.6.10)" |
| This is the total amount of memory currently available to |
| be allocated on the system, expressed in kilobytes. |
| This limit is adhered to |
| only if strict overcommit accounting is enabled (mode 2 in |
| .IR /proc/sys/vm/overcommit_memory ). |
| The limit is calculated according to the formula described under |
| .IR /proc/sys/vm/overcommit_memory . |
| For further details, see the kernel source file |
| .IR Documentation/vm/overcommit\-accounting.rst . |
| .TP |
| .IR Committed_AS " %lu" |
| The amount of memory presently allocated on the system. |
| The committed memory is a sum of all of the memory which |
| has been allocated by processes, even if it has not been |
| "used" by them as of yet. |
| A process which allocates 1 GB of memory (using |
| .BR malloc (3) |
| or similar), but touches only 300 MB of that memory will show up |
| as using only 300 MB of memory even if it has the address space |
| allocated for the entire 1 GB. |
| .IP |
| This 1 GB is memory which has been "committed" to by the VM |
| and can be used at any time by the allocating application. |
| With strict overcommit enabled on the system (mode 2 in |
| .IR /proc/sys/vm/overcommit_memory ), |
| allocations which would exceed the |
| .I CommitLimit |
| will not be permitted. |
| This is useful if one needs to guarantee that processes will not |
| fail due to lack of memory once that memory has been successfully allocated. |
| .TP |
| .IR VmallocTotal " %lu" |
| Total size of vmalloc memory area. |
| .TP |
| .IR VmallocUsed " %lu" |
| Amount of vmalloc area which is used. |
| Since Linux 4.4, |
| .\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0 |
| this field is no longer calculated, and is hard coded as 0. |
| See |
| .IR /proc/vmallocinfo . |
| .TP |
| .IR VmallocChunk " %lu" |
| Largest contiguous block of vmalloc area which is free. |
| Since Linux 4.4, |
| .\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0 |
| this field is no longer calculated and is hard coded as 0. |
| See |
| .IR /proc/vmallocinfo . |
| .TP |
| .IR HardwareCorrupted " %lu (since Linux 2.6.32)" |
| (\fBCONFIG_MEMORY_FAILURE\fP is required.) |
| [To be documented.] |
| .TP |
| .IR LazyFree " %lu (since Linux 4.12)" |
| Shows the amount of memory marked by |
| .BR madvise (2) |
| .BR MADV_FREE . |
| .TP |
| .IR AnonHugePages " %lu (since Linux 2.6.38)" |
| (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) |
| Non-file backed huge pages mapped into user-space page tables. |
| .TP |
| .IR ShmemHugePages " %lu (since Linux 4.8)" |
| (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) |
| Memory used by shared memory (shmem) and |
| .BR tmpfs (5) |
| allocated with huge pages. |
| .TP |
| .IR ShmemPmdMapped " %lu (since Linux 4.8)" |
| (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) |
| Shared memory mapped into user space with huge pages. |
| .TP |
| .IR CmaTotal " %lu (since Linux 3.1)" |
| Total CMA (Contiguous Memory Allocator) pages. |
| (\fBCONFIG_CMA\fP is required.) |
| .TP |
| .IR CmaFree " %lu (since Linux 3.1)" |
| Free CMA (Contiguous Memory Allocator) pages. |
| (\fBCONFIG_CMA\fP is required.) |
| .TP |
| .IR HugePages_Total " %lu" |
| (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
| The size of the pool of huge pages. |
| .TP |
| .IR HugePages_Free " %lu" |
| (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
| The number of huge pages in the pool that are not yet allocated. |
| .TP |
| .IR HugePages_Rsvd " %lu (since Linux 2.6.17)" |
| (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
| This is the number of huge pages for |
| which a commitment to allocate from the pool has been made, |
| but no allocation has yet been made. |
| These reserved huge pages |
| guarantee that an application will be able to allocate a |
| huge page from the pool of huge pages at fault time. |
| .TP |
| .IR HugePages_Surp " %lu (since Linux 2.6.24)" |
| (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
| This is the number of huge pages in |
| the pool above the value in |
| .IR /proc/sys/vm/nr_hugepages . |
| The maximum number of surplus huge pages is controlled by |
| .IR /proc/sys/vm/nr_overcommit_hugepages . |
| .TP |
| .IR Hugepagesize " %lu" |
| (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
| The size of huge pages. |
| .TP |
| .IR DirectMap4k " %lu (since Linux 2.6.27)" |
| Number of bytes of RAM linearly mapped by kernel in 4 kB pages. |
| (x86.) |
| .TP |
| .IR DirectMap4M " %lu (since Linux 2.6.27)" |
| Number of bytes of RAM linearly mapped by kernel in 4 MB pages. |
| (x86 with |
| .BR CONFIG_X86_64 |
| or |
| .BR CONFIG_X86_PAE |
| enabled.) |
| .TP |
| .IR DirectMap2M " %lu (since Linux 2.6.27)" |
| Number of bytes of RAM linearly mapped by kernel in 2 MB pages. |
| (x86 with neither |
| .BR CONFIG_X86_64 |
| nor |
| .BR CONFIG_X86_PAE |
| enabled.) |
| .TP |
| .IR DirectMap1G " %lu (since Linux 2.6.27)" |
| (x86 with |
| .BR CONFIG_X86_64 |
| and |
| .B CONFIG_X86_DIRECT_GBPAGES |
| enabled.) |
| .RE |
| .TP |
| .I /proc/modules |
| A text list of the modules that have been loaded by the system. |
| See also |
| .BR lsmod (8). |
| .TP |
| .I /proc/mounts |
| Before kernel 2.4.19, this file was a list |
| of all the filesystems currently mounted on the system. |
| With the introduction of per-process mount namespaces in Linux 2.4.19 (see |
| .BR mount_namespaces (7)), |
| this file became a link to |
| .IR /proc/self/mounts , |
| which lists the 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/x86/mtrr.txt |
| .\" commit 7225e75144b9718cbbe1820d9c011c809d5773fd |
| (or |
| .I Documentation/mtrr.txt |
| before Linux 2.6.28) |
| for details. |
| .TP |
| .I /proc/net |
| This directory contains various files and subdirectories containing |
| information about the networking layer. |
| The files contain ASCII structures and are, |
| therefore, readable with |
| .BR cat (1). |
| However, the standard |
| .BR netstat (8) |
| suite provides much cleaner access to these files. |
| .IP |
| With the advent of network namespaces, |
| various information relating to the network stack is virtualized (see |
| .BR network_namespaces (7)). |
| Thus, since Linux 2.6.25, |
| .\" commit e9720acd728a46cb40daa52c99a979f7c4ff195c |
| .IR /proc/net |
| is a symbolic link to the directory |
| .IR /proc/self/net , |
| which contains the same files and directories as listed below. |
| However, these files and directories now expose information |
| for the network namespace of which the process is a member. |
| .TP |
| .I /proc/net/arp |
| This holds an ASCII readable dump of the kernel ARP table used for |
| address resolutions. |
| It will show both dynamically learned and preprogrammed ARP entries. |
| The format is: |
| .IP |
| .in +4n |
| .EX |
| IP address HW type Flags HW address Mask Device |
| 192.168.0.50 0x1 0x2 00:50:BF:25:68:F3 * eth0 |
| 192.168.0.250 0x1 0xc 00:00:00:00:00:00 * eth0 |
| .EE |
| .in |
| .IP |
| Here "IP address" is the IPv4 address of the machine and the "HW type" |
| is the hardware type of the address from RFC\ 826. |
| The flags are the internal |
| flags of the ARP structure (as defined in |
| .IR /usr/include/linux/if_arp.h ) |
| and |
| the "HW address" is the data link layer mapping for that IP address if |
| it is known. |
| .TP |
| .I /proc/net/dev |
| The dev pseudo-file contains network device status information. |
| This gives |
| the number of received and sent packets, the number of errors and |
| collisions |
| and other basic statistics. |
| These are used by the |
| .BR ifconfig (8) |
| program to report device status. |
| The format is: |
| .IP |
| .EX |
| Inter\-| Receive | Transmit |
| face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed |
| lo: 2776770 11307 0 0 0 0 0 0 2776770 11307 0 0 0 0 0 0 |
| eth0: 1215645 2751 0 0 0 0 0 0 1782404 4324 0 0 0 427 0 0 |
| ppp0: 1622270 5552 1 0 0 0 0 0 354130 5669 0 0 0 0 0 0 |
| tap0: 7714 81 0 0 0 0 0 0 7714 81 0 0 0 0 0 0 |
| .EE |
| .\" .TP |
| .\" .I /proc/net/ipx |
| .\" No information. |
| .\" .TP |
| .\" .I /proc/net/ipx_route |
| .\" No information. |
| .TP |
| .I /proc/net/dev_mcast |
| Defined in |
| .IR /usr/src/linux/net/core/dev_mcast.c : |
| .IP |
| .in +4n |
| .EX |
| indx interface_name dmi_u dmi_g dmi_address |
| 2 eth0 1 0 01005e000001 |
| 3 eth1 1 0 01005e000001 |
| 4 eth2 1 0 01005e000001 |
| .EE |
| .in |
| .TP |
| .I /proc/net/igmp |
| Internet Group Management Protocol. |
| Defined in |
| .IR /usr/src/linux/net/core/igmp.c . |
| .TP |
| .I /proc/net/rarp |
| This file uses the same format as the |
| .I arp |
| file and contains the current reverse mapping database used to provide |
| .BR rarp (8) |
| reverse address lookup services. |
| If RARP is not configured into the |
| kernel, |
| this file will not be present. |
| .TP |
| .I /proc/net/raw |
| Holds a dump of the RAW socket table. |
| Much of the information is not of |
| use |
| apart from debugging. |
| The "sl" value is the kernel hash slot for the |
| socket, |
| the "local_address" is the local address and protocol number pair. |
| \&"St" is |
| the internal status of the socket. |
| The "tx_queue" and "rx_queue" are the |
| outgoing and incoming data queue in terms of kernel memory usage. |
| The "tr", "tm\->when", and "rexmits" fields are not used by RAW. |
| The "uid" |
| field holds the effective UID of the creator of the socket. |
| .\" .TP |
| .\" .I /proc/net/route |
| .\" No information, but looks similar to |
| .\" .BR route (8). |
| .TP |
| .I /proc/net/snmp |
| This file holds the ASCII data needed for the IP, ICMP, TCP, and UDP |
| management |
| information bases for an SNMP agent. |
| .TP |
| .I /proc/net/tcp |
| Holds a dump of the TCP socket table. |
| Much of the information is not |
| of use apart from debugging. |
| The "sl" value is the kernel hash slot |
| for the socket, the "local_address" is the local address and port number pair. |
| The "rem_address" is the remote address and port number pair |
| (if connected). |
| \&"St" is the internal status of the socket. |
| The "tx_queue" and "rx_queue" are the |
| outgoing and incoming data queue in terms of kernel memory usage. |
| The "tr", "tm\->when", and "rexmits" fields hold internal information of |
| the kernel socket state and are useful only for debugging. |
| The "uid" |
| field holds the effective UID of the creator of the socket. |
| .TP |
| .I /proc/net/udp |
| Holds a dump of the UDP socket table. |
| Much of the information is not of |
| use apart from debugging. |
| The "sl" value is the kernel hash slot for the |
| socket, the "local_address" is the local address and port number pair. |
| The "rem_address" is the remote address and port number pair |
| (if connected). |
| "St" is the internal status of the socket. |
| The "tx_queue" and "rx_queue" are the outgoing and incoming data queue |
| in terms of kernel memory usage. |
| The "tr", "tm\->when", and "rexmits" fields |
| are not used by UDP. |
| The "uid" |
| field holds the effective UID of the creator of the socket. |
| The format is: |
| .IP |
| .EX |
| sl local_address rem_address st tx_queue rx_queue tr rexmits tm\->when uid |
| 1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0 |
| 1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0 |
| 1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 |
| .EE |
| .TP |
| .I /proc/net/unix |
| Lists the UNIX domain sockets present within the system and their |
| status. |
| The format is: |
| .IP |
| .EX |
| Num RefCount Protocol Flags Type St Inode Path |
| 0: 00000002 00000000 00000000 0001 03 42 |
| 1: 00000001 00000000 00010000 0001 01 1948 /dev/printer |
| .EE |
| .IP |
| The fields are as follows: |
| .RS |
| .TP 10 |
| .IR Num : |
| the kernel table slot number. |
| .TP |
| .IR RefCount : |
| the number of users of the socket. |
| .TP |
| .IR Protocol : |
| currently always 0. |
| .TP |
| .IR Flags : |
| the internal kernel flags holding the status of the socket. |
| .TP |
| .IR Type : |
| the socket type. |
| For |
| .BR SOCK_STREAM |
| sockets, this is 0001; for |
| .BR SOCK_DGRAM |
| sockets, it is 0002; and for |
| .BR SOCK_SEQPACKET |
| sockets, it is 0005. |
| .TP |
| .IR St : |
| the internal state of the socket. |
| .TP |
| .IR Inode : |
| the inode number of the socket. |
| .TP |
| .IR Path : |
| the bound pathname (if any) of the socket. |
| Sockets in the abstract namespace are included in the list, |
| and are shown with a |
| .I Path |
| that commences with the character '@'. |
| .RE |
| .TP |
| .I /proc/net/netfilter/nfnetlink_queue |
| This file contains information about netfilter user-space queueing, if used. |
| Each line represents a queue. |
| Queues that have not been subscribed to |
| by user space are not shown. |
| .IP |
| .in +4n |
| .EX |
| 1 4207 0 2 65535 0 0 0 1 |
| (1) (2) (3)(4) (5) (6) (7) (8) |
| .EE |
| .in |
| .IP |
| The fields in each line are: |
| .RS 7 |
| .TP 5 |
| (1) |
| The ID of the queue. |
| This matches what is specified in the |
| .B \-\-queue\-num |
| or |
| .B \-\-queue\-balance |
| options to the |
| .BR iptables (8) |
| NFQUEUE target. |
| See |
| .BR iptables\-extensions (8) |
| for more information. |
| .TP |
| (2) |
| The netlink port ID subscribed to the queue. |
| .TP |
| (3) |
| The number of packets currently queued and waiting to be processed by |
| the application. |
| .TP |
| (4) |
| The copy mode of the queue. |
| It is either 1 (metadata only) or 2 |
| (also copy payload data to user space). |
| .TP |
| (5) |
| Copy range; that is, how many bytes of packet payload should be copied to |
| user space at most. |
| .TP |
| (6) |
| queue dropped. |
| Number of packets that had to be dropped by the kernel because |
| too many packets are already waiting for user space to send back the mandatory |
| accept/drop verdicts. |
| .TP |
| (7) |
| queue user dropped. |
| Number of packets that were dropped within the netlink |
| subsystem. |
| Such drops usually happen when the corresponding socket buffer is |
| full; that is, user space is not able to read messages fast enough. |
| .TP |
| (8) |
| sequence number. |
| Every queued packet is associated with a (32-bit) |
| monotonically increasing sequence number. |
| This shows the ID of the most recent packet queued. |
| .RE |
| .IP |
| The last number exists only for compatibility reasons and is always 1. |
| .TP |
| .I /proc/partitions |
| Contains the major and minor numbers of each partition as well as the number |
| of 1024-byte blocks and the partition name. |
| .TP |
| .I /proc/pci |
| This is a listing of all PCI devices found during kernel initialization |
| and their configuration. |
| .IP |
| This file has been deprecated in favor of a new |
| .I /proc |
| interface for PCI |
| .RI ( /proc/bus/pci ). |
| It became optional in Linux 2.2 (available with |
| .B CONFIG_PCI_OLD_PROC |
| set at kernel compilation). |
| It became once more nonoptionally enabled in Linux 2.4. |
| Next, it was deprecated in Linux 2.6 (still available with |
| .B CONFIG_PCI_LEGACY_PROC |
| set), and finally removed altogether since Linux 2.6.17. |
| .\" FIXME Document /proc/sched_debug (since Linux 2.6.23) |
| .\" See also /proc/[pid]/sched |
| .TP |
| .IR /proc/profile " (since Linux 2.4)" |
| This file is present only if the kernel was booted with the |
| .I profile=1 |
| command-line option. |
| It exposes kernel profiling information in a binary format for use by |
| .BR readprofile (1). |
| Writing (e.g., an empty string) to this file resets the profiling counters; |
| on some architectures, |
| writing a binary integer "profiling multiplier" of size |
| .IR sizeof(int) |
| sets the profiling interrupt frequency. |
| .TP |
| .I /proc/scsi |
| A directory with the |
| .I scsi |
| mid-level pseudo-file and various SCSI low-level |
| driver directories, |
| which contain a file for each SCSI host in this system, all of |
| which give the status of some part of the SCSI IO subsystem. |
| These files contain ASCII structures and are, therefore, readable with |
| .BR cat (1). |
| .IP |
| You can also write to some of the files to reconfigure the subsystem or |
| switch certain features on or off. |
| .TP |
| .I /proc/scsi/scsi |
| This is a listing of all SCSI devices known to the kernel. |
| The listing is similar to the one seen during bootup. |
| scsi currently supports only the \fIadd\-single\-device\fP command which |
| allows root to add a hotplugged device to the list of known devices. |
| .IP |
| The command |
| .IP |
| .in +4n |
| .EX |
| echo \(aqscsi add\-single\-device 1 0 5 0\(aq > /proc/scsi/scsi |
| .EE |
| .in |
| .IP |
| will cause |
| host scsi1 to scan on SCSI channel 0 for a device on ID 5 LUN 0. |
| If there |
| is already a device known on this address or the address is invalid, an |
| error will be returned. |
| .TP |
| .I /proc/scsi/[drivername] |
| \fI[drivername]\fP can currently be NCR53c7xx, aha152x, aha1542, aha1740, |
| aic7xxx, buslogic, eata_dma, eata_pio, fdomain, in2000, pas16, qlogic, |
| scsi_debug, seagate, t128, u15\-24f, ultrastore, or wd7000. |
| These directories show up for all drivers that registered at least one |
| SCSI HBA. |
| Every directory contains one file per registered host. |
| Every host-file is named after the number the host was assigned during |
| initialization. |
| .IP |
| Reading these files will usually show driver and host configuration, |
| statistics, and so on. |
| .IP |
| Writing to these files allows different things on different hosts. |
| For example, with the \fIlatency\fP and \fInolatency\fP commands, |
| root can switch on and off command latency measurement code in the |
| eata_dma driver. |
| With the \fIlockup\fP and \fIunlock\fP commands, |
| root can control bus lockups simulated by the scsi_debug driver. |
| .TP |
| .I /proc/self |
| This directory refers to the process accessing the |
| .I /proc |
| filesystem, |
| and is identical to the |
| .I /proc |
| directory named by the process ID of the same process. |
| .TP |
| .I /proc/slabinfo |
| Information about kernel caches. |
| See |
| .BR slabinfo (5) |
| for details. |
| .TP |
| .I /proc/stat |
| kernel/system statistics. |
| Varies with architecture. |
| Common |
| entries include: |
| .RS |
| .TP |
| .I cpu 10132153 290696 3084719 46828483 16683 0 25195 0 175628 0 |
| .TQ |
| .I cpu0 1393280 32966 572056 13343292 6130 0 17875 0 23933 0 |
| The amount of time, measured in units of |
| USER_HZ (1/100ths of a second on most architectures, use |
| .IR sysconf(_SC_CLK_TCK) |
| to obtain the right value), |
| .\" 1024 on Alpha and ia64 |
| that the system ("cpu" line) or the specific CPU ("cpu\fIN\fR" line) |
| spent in various states: |
| .RS |
| .TP |
| .I user |
| (1) Time spent in user mode. |
| .TP |
| .I nice |
| (2) Time spent in user mode with low priority (nice). |
| .TP |
| .I system |
| (3) Time spent in system mode. |
| .TP |
| .I idle |
| (4) Time spent in the idle task. |
| .\" FIXME . Actually, the following info about the /proc/stat 'cpu' field |
| .\" does not seem to be quite right (at least in 2.6.12 or 3.6): |
| .\" the idle time in /proc/uptime does not quite match this value |
| This value should be USER_HZ times the |
| second entry in the |
| .I /proc/uptime |
| pseudo-file. |
| .TP |
| .IR iowait " (since Linux 2.5.41)" |
| (5) Time waiting for I/O to complete. |
| This value is not reliable, for the following reasons: |
| .\" See kernel commit 9c240d757658a3ae9968dd309e674c61f07c7f48 |
| .RS |
| .IP 1. 3 |
| The CPU will not wait for I/O to complete; |
| iowait is the time that a task is waiting for I/O to complete. |
| When a CPU goes into idle state for outstanding task I/O, |
| another task will be scheduled on this CPU. |
| .IP 2. |
| On a multi-core CPU, |
| the task waiting for I/O to complete is not running on any CPU, |
| so the iowait of each CPU is difficult to calculate. |
| .IP 3. |
| The value in this field may |
| .I decrease |
| in certain conditions. |
| .RE |
| .TP |
| .IR irq " (since Linux 2.6.0)" |
| .\" Precisely: Linux 2.6.0-test4 |
| (6) Time servicing interrupts. |
| .TP |
| .IR softirq " (since Linux 2.6.0)" |
| .\" Precisely: Linux 2.6.0-test4 |
| (7) Time servicing softirqs. |
| .TP |
| .IR steal " (since Linux 2.6.11)" |
| (8) Stolen time, which is the time spent in other operating systems when |
| running in a virtualized environment |
| .TP |
| .IR guest " (since Linux 2.6.24)" |
| (9) Time spent running a virtual CPU for guest |
| operating systems under the control of the Linux kernel. |
| .\" See Changelog entry for 5e84cfde51cf303d368fcb48f22059f37b3872de |
| .TP |
| .IR guest_nice " (since Linux 2.6.33)" |
| .\" commit ce0e7b28fb75cb003cfc8d0238613aaf1c55e797 |
| (10) Time spent running a niced guest (virtual CPU for guest |
| operating systems under the control of the Linux kernel). |
| .RE |
| .TP |
| \fIpage 5741 1808\fP |
| The number of pages the system paged in and the number that were paged |
| out (from disk). |
| .TP |
| \fIswap 1 0\fP |
| The number of swap pages that have been brought in and out. |
| .TP |
| .\" FIXME . The following is not the full picture for the 'intr' of |
| .\" /proc/stat on 2.6: |
| \fIintr 1462898\fP |
| This line shows counts of interrupts serviced since boot time, |
| for each of the possible system interrupts. |
| The first column is the total of all interrupts serviced |
| including unnumbered architecture specific interrupts; |
| each subsequent column is the total for that particular numbered interrupt. |
| Unnumbered interrupts are not shown, only summed into the total. |
| .TP |
| \fIdisk_io: (2,0):(31,30,5764,1,2) (3,0):\fP... |
| (major,disk_idx):(noinfo, read_io_ops, blks_read, write_io_ops, blks_written) |
| .br |
| (Linux 2.4 only) |
| .TP |
| \fIctxt 115315\fP |
| The number of context switches that the system underwent. |
| .TP |
| \fIbtime 769041601\fP |
| boot time, in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC). |
| .TP |
| \fIprocesses 86031\fP |
| Number of forks since boot. |
| .TP |
| \fIprocs_running 6\fP |
| Number of processes in runnable state. |
| (Linux 2.5.45 onward.) |
| .TP |
| \fIprocs_blocked 2\fP |
| Number of processes blocked waiting for I/O to complete. |
| (Linux 2.5.45 onward.) |
| .TP |
| .I softirq 229245889 94 60001584 13619 5175704 2471304 28 51212741 59130143 0 51240672 |
| .\" commit d3d64df21d3d0de675a0d3ffa7c10514f3644b30 |
| This line shows the number of softirq for all CPUs. |
| The first column is the total of all softirqs and |
| each subsequent column is the total for particular softirq. |
| (Linux 2.6.31 onward.) |
| .RE |
| .TP |
| .I /proc/swaps |
| Swap areas in use. |
| See also |
| .BR swapon (8). |
| .TP |
| .I /proc/sys |
| This directory (present since 1.3.57) contains a number of files |
| and subdirectories corresponding to kernel variables. |
| These variables can be read and sometimes modified using |
| the \fI/proc\fP filesystem, and the (deprecated) |
| .BR sysctl (2) |
| system call. |
| .IP |
| String values may be terminated by either \(aq\e0\(aq or \(aq\en\(aq. |
| .IP |
| Integer and long values may be written either in decimal or in |
| hexadecimal notation (e.g., 0x3FFF). |
| When writing multiple integer or long values, these may be separated |
| by any of the following whitespace characters: |
| \(aq\ \(aq, \(aq\et\(aq, or \(aq\en\(aq. |
| Using other separators leads to the error |
| .BR EINVAL . |
| .TP |
| .IR /proc/sys/abi " (since Linux 2.4.10)" |
| This directory may contain files with application binary information. |
| .\" On some systems, it is not present. |
| See the Linux kernel source file |
| .I Documentation/sysctl/abi.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 filesystems. |
| .TP |
| .IR /proc/sys/fs/aio-max-nr " and " /proc/sys/fs/aio-nr " (since Linux 2.6.4)" |
| .I aio-nr |
| is the running total of the number of events specified by |
| .BR io_setup (2) |
| calls for all currently active AIO contexts. |
| If |
| .I aio-nr |
| reaches |
| .IR aio-max-nr , |
| then |
| .BR io_setup (2) |
| will fail with the error |
| .BR EAGAIN . |
| Raising |
| .I aio-max-nr |
| does not result in the preallocation or resizing |
| of any kernel data structures. |
| .TP |
| .I /proc/sys/fs/binfmt_misc |
| Documentation for files in this directory can be found |
| in the Linux kernel source in the file |
| .IR Documentation/admin\-guide/binfmt\-misc.rst |
| (or in |
| .IR Documentation/binfmt_misc.txt |
| on older kernels). |
| .TP |
| .IR /proc/sys/fs/dentry\-state " (since Linux 2.2)" |
| This file contains information about the status of the |
| directory cache (dcache). |
| The file contains six numbers, |
| .IR nr_dentry ", " nr_unused ", " age_limit " (age in seconds)," |
| .I want_pages |
| (pages requested by system) and two dummy values. |
| .RS |
| .IP * 2 |
| .I nr_dentry |
| is the number of allocated dentries (dcache entries). |
| This field is unused in Linux 2.2. |
| .IP * |
| .I nr_unused |
| is the number of unused dentries. |
| .IP * |
| .I age_limit |
| .\" looks like this is unused in kernels 2.2 to 2.6 |
| is the age in seconds after which dcache entries |
| can be reclaimed when memory is short. |
| .IP * |
| .I want_pages |
| .\" looks like this is unused in kernels 2.2 to 2.6 |
| is nonzero when the kernel has called shrink_dcache_pages() and the |
| dcache isn't pruned yet. |
| .RE |
| .TP |
| .I /proc/sys/fs/dir\-notify\-enable |
| This file can be used to disable or enable the |
| .I dnotify |
| interface described in |
| .BR fcntl (2) |
| on a system-wide basis. |
| A value of 0 in this file disables the interface, |
| and a value of 1 enables it. |
| .TP |
| .I /proc/sys/fs/dquot\-max |
| This file shows the maximum number of cached disk quota entries. |
| On some (2.4) systems, it is not present. |
| If the number of free cached disk quota entries is very low and |
| you have some awesome number of simultaneous system users, |
| you might want to raise the limit. |
| .TP |
| .I /proc/sys/fs/dquot\-nr |
| This file shows the number of allocated disk quota |
| entries and the number of free disk quota entries. |
| .TP |
| .IR /proc/sys/fs/epoll " (since Linux 2.6.28)" |
| This directory contains the file |
| .IR max_user_watches , |
| which can be used to limit the amount of kernel memory consumed by the |
| .I epoll |
| interface. |
| For further details, see |
| .BR epoll (7). |
| .TP |
| .I /proc/sys/fs/file\-max |
| This file defines |
| a system-wide limit on the number of open files for all processes. |
| System calls that fail when encountering this limit fail with the error |
| .BR ENFILE . |
| (See also |
| .BR setrlimit (2), |
| which can be used by a process to set the per-process limit, |
| .BR RLIMIT_NOFILE , |
| on the number of files it may open.) |
| If you get lots |
| of error messages in the kernel log about running out of file handles |
| (open file descriptions) |
| (look for "VFS: file\-max limit <number> reached"), |
| try increasing this value: |
| .IP |
| .in +4n |
| .EX |
| echo 100000 > /proc/sys/fs/file\-max |
| .EE |
| .in |
| .IP |
| Privileged processes |
| .RB ( CAP_SYS_ADMIN ) |
| can override the |
| .I file\-max |
| limit. |
| .TP |
| .I /proc/sys/fs/file\-nr |
| This (read-only) file contains three numbers: |
| the number of allocated file handles |
| (i.e., the number of open file descriptions; see |
| .BR open (2)); |
| the number of free file handles; |
| and the maximum number of file handles (i.e., the same value as |
| .IR /proc/sys/fs/file\-max ). |
| If the number of allocated file handles is close to the |
| maximum, you should consider increasing the maximum. |
| Before Linux 2.6, |
| the kernel allocated file handles dynamically, |
| but it didn't free them again. |
| Instead the free file handles were kept in a list for reallocation; |
| the "free file handles" value indicates the size of that list. |
| A large number of free file handles indicates that there was |
| a past peak in the usage of open file handles. |
| Since Linux 2.6, the kernel does deallocate freed file handles, |
| and the "free file handles" value is always zero. |
| .TP |
| .IR /proc/sys/fs/inode\-max " (only present until Linux 2.2)" |
| This file contains the maximum number of in-memory inodes. |
| This value should be 3\(en4 times larger |
| than the value in |
| .IR file\-max , |
| since \fIstdin\fP, \fIstdout\fP |
| and network sockets also need an inode to handle them. |
| When you regularly run out of inodes, you need to increase this value. |
| .IP |
| Starting with Linux 2.4, |
| there is no longer a static limit on the number of inodes, |
| and this file is removed. |
| .TP |
| .I /proc/sys/fs/inode\-nr |
| This file contains the first two values from |
| .IR inode\-state . |
| .TP |
| .I /proc/sys/fs/inode\-state |
| This file |
| contains seven numbers: |
| .IR nr_inodes , |
| .IR nr_free_inodes , |
| .IR preshrink , |
| and four dummy values (always zero). |
| .IP |
| .I nr_inodes |
| is the number of inodes the system has allocated. |
| .\" This can be slightly more than |
| .\" .I inode\-max |
| .\" because Linux allocates them one page full at a time. |
| .I nr_free_inodes |
| represents the number of free inodes. |
| .IP |
| .I preshrink |
| is nonzero when the |
| .I nr_inodes |
| > |
| .I inode\-max |
| and the system needs to prune the inode list instead of allocating more; |
| since Linux 2.4, this field is a dummy value (always zero). |
| .TP |
| .IR /proc/sys/fs/inotify " (since Linux 2.6.13)" |
| This directory contains files |
| .IR max_queued_events ", " max_user_instances ", and " max_user_watches , |
| that can be used to limit the amount of kernel memory consumed by the |
| .I inotify |
| interface. |
| For further details, see |
| .BR inotify (7). |
| .TP |
| .I /proc/sys/fs/lease\-break\-time |
| This file specifies the grace period that the kernel grants to a process |
| holding a file lease |
| .RB ( fcntl (2)) |
| after it has sent a signal to that process notifying it |
| that another process is waiting to open the file. |
| If the lease holder does not remove or downgrade the lease within |
| this grace period, the kernel forcibly breaks the lease. |
| .TP |
| .I /proc/sys/fs/leases\-enable |
| This file can be used to enable or disable file leases |
| .RB ( fcntl (2)) |
| on a system-wide basis. |
| If this file contains the value 0, leases are disabled. |
| A nonzero value enables leases. |
| .TP |
| .IR /proc/sys/fs/mount\-max " (since Linux 4.9)" |
| .\" commit d29216842a85c7970c536108e093963f02714498 |
| The value in this file specifies the maximum number of mounts that may exist |
| in a mount namespace. |
| The default value in this file is 100,000. |
| .TP |
| .IR /proc/sys/fs/mqueue " (since Linux 2.6.6)" |
| This directory contains files |
| .IR msg_max ", " msgsize_max ", and " queues_max , |
| controlling the resources used by POSIX message queues. |
| See |
| .BR mq_overview (7) |
| for details. |
| .TP |
| .IR /proc/sys/fs/nr_open " (since Linux 2.6.25)" |
| .\" commit 9cfe015aa424b3c003baba3841a60dd9b5ad319b |
| This file imposes a ceiling on the value to which the |
| .BR RLIMIT_NOFILE |
| resource limit can be raised (see |
| .BR getrlimit (2)). |
| This ceiling is enforced for both unprivileged and privileged process. |
| The default value in this file is 1048576. |
| (Before Linux 2.6.25, the ceiling for |
| .BR RLIMIT_NOFILE |
| was hard-coded to the same value.) |
| .TP |
| .IR /proc/sys/fs/overflowgid " and " /proc/sys/fs/overflowuid |
| These files |
| allow you to change the value of the fixed UID and GID. |
| The default is 65534. |
| Some filesystems support only 16-bit UIDs and GIDs, although in Linux |
| UIDs and GIDs are 32 bits. |
| When one of these filesystems is mounted |
| with writes enabled, any UID or GID that would exceed 65535 is translated |
| to the overflow value before being written to disk. |
| .TP |
| .IR /proc/sys/fs/pipe\-max\-size " (since Linux 2.6.35)" |
| See |
| .BR pipe (7). |
| .TP |
| .IR /proc/sys/fs/pipe\-user\-pages\-hard " (since Linux 4.5)" |
| See |
| .BR pipe (7). |
| .TP |
| .IR /proc/sys/fs/pipe\-user\-pages\-soft " (since Linux 4.5)" |
| See |
| .BR pipe (7). |
| .TP |
| .IR /proc/sys/fs/protected_fifos " (since Linux 4.19)" |
| The value in this file is/can be set to one of the following: |
| .RS |
| .TP 4 |
| 0 |
| Writing to FIFOs is unrestricted. |
| .TP |
| 1 |
| Don't allow |
| .B O_CREAT |
| .BR open (2) |
| on FIFOs that the caller doesn't own in world-writable sticky directories, |
| unless the FIFO is owned by the owner of the directory. |
| .TP |
| 2 |
| As for the value 1, |
| but the restriction also applies to group-writable sticky directories. |
| .RE |
| .IP |
| The intent of the above protections is to avoid unintentional writes to an |
| attacker-controlled FIFO when a program expected to create a regular file. |
| .TP |
| .IR /proc/sys/fs/protected_hardlinks " (since Linux 3.6)" |
| .\" commit 800179c9b8a1e796e441674776d11cd4c05d61d7 |
| When the value in this file is 0, |
| no restrictions are placed on the creation of hard links |
| (i.e., this is the historical behavior before Linux 3.6). |
| When the value in this file is 1, |
| a hard link can be created to a target file |
| only if one of the following conditions is true: |
| .RS |
| .IP * 3 |
| The calling process has the |
| .BR CAP_FOWNER |
| capability in its user namespace |
| and the file UID has a mapping in the namespace. |
| .IP * |
| The filesystem UID of the process creating the link matches |
| the owner (UID) of the target file |
| (as described in |
| .BR credentials (7), |
| a process's filesystem UID is normally the same as its effective UID). |
| .IP * |
| All of the following conditions are true: |
| .RS 4 |
| .IP \(bu 3 |
| the target is a regular file; |
| .IP \(bu |
| the target file does not have its set-user-ID mode bit enabled; |
| .IP \(bu |
| the target file does not have both its set-group-ID and |
| group-executable mode bits enabled; and |
| .IP \(bu |
| the caller has permission to read and write the target file |
| (either via the file's permissions mask or because it has |
| suitable capabilities). |
| .RE |
| .RE |
| .IP |
| The default value in this file is 0. |
| Setting the value to 1 |
| prevents a longstanding class of security issues caused by |
| hard-link-based time-of-check, time-of-use races, |
| most commonly seen in world-writable directories such as |
| .IR /tmp . |
| The common method of exploiting this flaw |
| is to cross privilege boundaries when following a given hard link |
| (i.e., a root process follows a hard link created by another user). |
| Additionally, on systems without separated partitions, |
| this stops unauthorized users from "pinning" vulnerable set-user-ID and |
| set-group-ID files against being upgraded by |
| the administrator, or linking to special files. |
| .TP |
| .IR /proc/sys/fs/protected_regular " (since Linux 4.19)" |
| The value in this file is/can be set to one of the following: |
| .RS |
| .TP 4 |
| 0 |
| Writing to regular files is unrestricted. |
| .TP |
| 1 |
| Don't allow |
| .B O_CREAT |
| .BR open (2) |
| on regular files that the caller doesn't own in |
| world-writable sticky directories, |
| unless the regular file is owned by the owner of the directory. |
| .TP |
| 2 |
| As for the value 1, |
| but the restriction also applies to group-writable sticky directories. |
| .RE |
| .IP |
| The intent of the above protections is similar to |
| .IR protected_fifos , |
| but allows an application to |
| avoid writes to an attacker-controlled regular file, |
| where the application expected to create one. |
| .TP |
| .IR /proc/sys/fs/protected_symlinks " (since Linux 3.6)" |
| .\" commit 800179c9b8a1e796e441674776d11cd4c05d61d7 |
| When the value in this file is 0, |
| no restrictions are placed on following symbolic links |
| (i.e., this is the historical behavior before Linux 3.6). |
| When the value in this file is 1, symbolic links are followed only |
| in the following circumstances: |
| .RS |
| .IP * 3 |
| the filesystem UID of the process following the link matches |
| the owner (UID) of the symbolic link |
| (as described in |
| .BR credentials (7), |
| a process's filesystem UID is normally the same as its effective UID); |
| .IP * |
| the link is not in a sticky world-writable directory; or |
| .IP * |
| the symbolic link and its parent directory have the same owner (UID) |
| .RE |
| .IP |
| A system call that fails to follow a symbolic link |
| because of the above restrictions returns the error |
| .BR EACCES |
| in |
| .IR errno . |
| .IP |
| The default value in this file is 0. |
| Setting the value to 1 avoids a longstanding class of security issues |
| based on time-of-check, time-of-use races when accessing symbolic links. |
| .TP |
| .IR /proc/sys/fs/suid_dumpable " (since Linux 2.6.13)" |
| .\" The following is based on text from Documentation/sysctl/kernel.txt |
| The value in this file is assigned to a process's "dumpable" flag |
| in the circumstances described in |
| .BR prctl (2). |
| In effect, |
| the value in this file determines whether core dump files are |
| produced for set-user-ID or otherwise protected/tainted binaries. |
| The "dumpable" setting also affects the ownership of files in a process's |
| .IR /proc/[pid] |
| directory, as described above. |
| .IP |
| Three different integer values can be specified: |
| .RS |
| .TP |
| \fI0\ (default)\fP |
| .\" In kernel source: SUID_DUMP_DISABLE |
| This provides the traditional (pre-Linux 2.6.13) behavior. |
| A core dump will not be produced for a process which has |
| changed credentials (by calling |
| .BR seteuid (2), |
| .BR setgid (2), |
| or similar, or by executing a set-user-ID or set-group-ID program) |
| or whose binary does not have read permission enabled. |
| .TP |
| \fI1\ ("debug")\fP |
| .\" In kernel source: SUID_DUMP_USER |
| All processes dump core when possible. |
| (Reasons why a process might nevertheless not dump core are described in |
| .BR core (5).) |
| The core dump is owned by the filesystem user ID of the dumping process |
| and no security is applied. |
| This is intended for system debugging situations only: |
| this mode is insecure because it allows unprivileged users to |
| examine the memory contents of privileged processes. |
| .TP |
| \fI2\ ("suidsafe")\fP |
| .\" In kernel source: SUID_DUMP_ROOT |
| Any binary which normally would not be dumped (see "0" above) |
| is dumped readable by root only. |
| This allows the user to remove the core dump file but not to read it. |
| For security reasons core dumps in this mode will not overwrite one |
| another or other files. |
| This mode is appropriate when administrators are |
| attempting to debug problems in a normal environment. |
| .IP |
| Additionally, since Linux 3.6, |
| .\" 9520628e8ceb69fa9a4aee6b57f22675d9e1b709 |
| .I /proc/sys/kernel/core_pattern |
| must either be an absolute pathname |
| or a pipe command, as detailed in |
| .BR core (5). |
| Warnings will be written to the kernel log if |
| .I core_pattern |
| does not follow these rules, and no core dump will be produced. |
| .\" 54b501992dd2a839e94e76aa392c392b55080ce8 |
| .RE |
| .IP |
| For details of the effect of a process's "dumpable" setting |
| on ptrace access mode checking, see |
| .BR ptrace (2). |
| .TP |
| .I /proc/sys/fs/super\-max |
| This file |
| controls the maximum number of superblocks, and |
| thus the maximum number of mounted filesystems the kernel |
| can have. |
| You need increase only |
| .I super\-max |
| if you need to mount more filesystems than the current value in |
| .I super\-max |
| allows you to. |
| .TP |
| .I /proc/sys/fs/super\-nr |
| This file |
| contains the number of filesystems currently mounted. |
| .TP |
| .I /proc/sys/kernel |
| This directory contains files controlling a range of kernel parameters, |
| as described below. |
| .TP |
| .I /proc/sys/kernel/acct |
| This file |
| contains three numbers: |
| .IR highwater , |
| .IR lowwater , |
| and |
| .IR frequency . |
| If BSD-style process accounting is enabled, these values control |
| its behavior. |
| If free space on filesystem where the log lives goes below |
| .I lowwater |
| percent, accounting suspends. |
| If free space gets above |
| .I highwater |
| percent, accounting resumes. |
| .I frequency |
| determines |
| how often the kernel checks the amount of free space (value is in |
| seconds). |
| Default values are 4, 2 and 30. |
| That is, suspend accounting if 2% or less space is free; resume it |
| if 4% or more space is free; consider information about amount of free space |
| valid for 30 seconds. |
| .TP |
| .IR /proc/sys/kernel/auto_msgmni " (Linux 2.6.27 to 3.18)" |
| .\" commit 9eefe520c814f6f62c5d36a2ddcd3fb99dfdb30e (introduces feature) |
| .\" commit 0050ee059f7fc86b1df2527aaa14ed5dc72f9973 (rendered redundant) |
| From Linux 2.6.27 to 3.18, |
| this file was used to control recomputing of the value in |
| .IR /proc/sys/kernel/msgmni |
| upon the addition or removal of memory or upon IPC namespace creation/removal. |
| Echoing "1" into this file enabled |
| .I msgmni |
| automatic recomputing (and triggered a recomputation of |
| .I msgmni |
| based on the current amount of available memory and number of IPC namespaces). |
| Echoing "0" disabled automatic recomputing. |
| (Automatic recomputing was also disabled if a value was explicitly assigned to |
| .IR /proc/sys/kernel/msgmni .) |
| The default value in |
| .I auto_msgmni |
| was 1. |
| .IP |
| Since Linux 3.19, the content of this file has no effect (because |
| .IR msgmni |
| .\" FIXME Must document the 3.19 'msgmni' changes. |
| defaults to near the maximum value possible), |
| and reads from this file always return the value "0". |
| .TP |
| .IR /proc/sys/kernel/cap_last_cap " (since Linux 3.2)" |
| See |
| .BR capabilities (7). |
| .TP |
| .IR /proc/sys/kernel/cap\-bound " (from Linux 2.2 to 2.6.24)" |
| This file holds the value of the kernel |
| .I "capability bounding set" |
| (expressed as a signed decimal number). |
| This set is ANDed against the capabilities permitted to a process |
| during |
| .BR execve (2). |
| Starting with Linux 2.6.25, |
| the system-wide capability bounding set disappeared, |
| and was replaced by a per-thread bounding set; see |
| .BR capabilities (7). |
| .TP |
| .I /proc/sys/kernel/core_pattern |
| See |
| .BR core (5). |
| .TP |
| .I /proc/sys/kernel/core_pipe_limit |
| See |
| .BR core (5). |
| .TP |
| .I /proc/sys/kernel/core_uses_pid |
| See |
| .BR core (5). |
| .TP |
| .I /proc/sys/kernel/ctrl\-alt\-del |
| This file |
| controls the handling of Ctrl-Alt-Del from the keyboard. |
| When the value in this file is 0, Ctrl-Alt-Del is trapped and |
| sent to the |
| .BR init (1) |
| program to handle a graceful restart. |
| When the value is greater than zero, Linux's reaction to a Vulcan |
| Nerve Pinch (tm) will be an immediate reboot, without even |
| syncing its dirty buffers. |
| Note: when a program (like dosemu) has the keyboard in "raw" |
| mode, the ctrl-alt-del is intercepted by the program before it |
| ever reaches the kernel tty layer, and it's up to the program |
| to decide what to do with it. |
| .TP |
| .IR /proc/sys/kernel/dmesg_restrict " (since Linux 2.6.37)" |
| The value in this file determines who can see kernel syslog contents. |
| A value of 0 in this file imposes no restrictions. |
| If the value is 1, only privileged users can read the kernel syslog. |
| (See |
| .BR syslog (2) |
| for more details.) |
| Since Linux 3.4, |
| .\" commit 620f6e8e855d6d447688a5f67a4e176944a084e8 |
| only users with the |
| .BR CAP_SYS_ADMIN |
| capability may change the value in this file. |
| .TP |
| .IR /proc/sys/kernel/domainname " and " /proc/sys/kernel/hostname |
| can be used to set the NIS/YP domainname and the |
| hostname of your box in exactly the same way as the commands |
| .BR domainname (1) |
| and |
| .BR hostname (1), |
| that is: |
| .IP |
| .in +4n |
| .EX |
| .RB "#" " echo \(aqdarkstar\(aq > /proc/sys/kernel/hostname" |
| .RB "#" " echo \(aqmydomain\(aq > /proc/sys/kernel/domainname" |
| .EE |
| .in |
| .IP |
| has the same effect as |
| .IP |
| .in +4n |
| .EX |
| .RB "#" " hostname \(aqdarkstar\(aq" |
| .RB "#" " domainname \(aqmydomain\(aq" |
| .EE |
| .in |
| .IP |
| Note, however, that the classic darkstar.frop.org has the |
| hostname "darkstar" and DNS (Internet Domain Name Server) |
| domainname "frop.org", not to be confused with the NIS (Network |
| Information Service) or YP (Yellow Pages) domainname. |
| These two |
| domain names are in general different. |
| For a detailed discussion |
| see the |
| .BR hostname (1) |
| man page. |
| .TP |
| .I /proc/sys/kernel/hotplug |
| This file |
| contains the pathname for the hotplug policy agent. |
| The default value in this file is |
| .IR /sbin/hotplug . |
| .TP |
| .\" Removed in commit 87f504e5c78b910b0c1d6ffb89bc95e492322c84 (tglx/history.git) |
| .IR /proc/sys/kernel/htab\-reclaim " (before Linux 2.4.9.2)" |
| (PowerPC only) If this file is set to a nonzero value, |
| the PowerPC htab |
| .\" removed in commit 1b483a6a7b2998e9c98ad985d7494b9b725bd228, before 2.6.28 |
| (see kernel file |
| .IR Documentation/powerpc/ppc_htab.txt ) |
| is pruned |
| each time the system hits the idle loop. |
| .TP |
| .IR /proc/sys/kernel/keys/* |
| This directory contains various files that define parameters and limits |
| for the key-management facility. |
| These files are described in |
| .BR keyrings (7). |
| .TP |
| .IR /proc/sys/kernel/kptr_restrict " (since Linux 2.6.38)" |
| .\" 455cd5ab305c90ffc422dd2e0fb634730942b257 |
| The value in this file determines whether kernel addresses are exposed via |
| .I /proc |
| files and other interfaces. |
| A value of 0 in this file imposes no restrictions. |
| If the value is 1, kernel pointers printed using the |
| .I %pK |
| format specifier will be replaced with zeros unless the user has the |
| .BR CAP_SYSLOG |
| capability. |
| If the value is 2, kernel pointers printed using the |
| .I %pK |
| format specifier will be replaced with zeros regardless |
| of the user's capabilities. |
| The initial default value for this file was 1, |
| but the default was changed |
| .\" commit 411f05f123cbd7f8aa1edcae86970755a6e2a9d9 |
| to 0 in Linux 2.6.39. |
| Since Linux 3.4, |
| .\" commit 620f6e8e855d6d447688a5f67a4e176944a084e8 |
| only users with the |
| .BR CAP_SYS_ADMIN |
| capability can change the value in this file. |
| .TP |
| .I /proc/sys/kernel/l2cr |
| (PowerPC only) This file |
| contains a flag that controls the L2 cache of G3 processor |
| boards. |
| If 0, the cache is disabled. |
| Enabled if nonzero. |
| .TP |
| .I /proc/sys/kernel/modprobe |
| This file contains the pathname for the kernel module loader. |
| The default value is |
| .IR /sbin/modprobe . |
| The file is present only if the kernel is built with the |
| .B CONFIG_MODULES |
| .RB ( CONFIG_KMOD |
| in Linux 2.6.26 and earlier) |
| option enabled. |
| It is described by the Linux kernel source file |
| .I Documentation/kmod.txt |
| (present only in kernel 2.4 and earlier). |
| .TP |
| .IR /proc/sys/kernel/modules_disabled " (since Linux 2.6.31)" |
| .\" 3d43321b7015387cfebbe26436d0e9d299162ea1 |
| .\" From Documentation/sysctl/kernel.txt |
| A toggle value indicating if modules are allowed to be loaded |
| in an otherwise modular kernel. |
| This toggle defaults to off (0), but can be set true (1). |
| Once true, modules can be neither loaded nor unloaded, |
| and the toggle cannot be set back to false. |
| The file is present only if the kernel is built with the |
| .B CONFIG_MODULES |
| option enabled. |
| .TP |
| .IR /proc/sys/kernel/msgmax " (since Linux 2.2)" |
| This file defines |
| a system-wide limit specifying the maximum number of bytes in |
| a single message written on a System V message queue. |
| .TP |
| .IR /proc/sys/kernel/msgmni " (since Linux 2.4)" |
| This file defines the system-wide limit on the number of |
| message queue identifiers. |
| See also |
| .IR /proc/sys/kernel/auto_msgmni . |
| .TP |
| .IR /proc/sys/kernel/msgmnb " (since Linux 2.2)" |
| This file defines a system-wide parameter used to initialize the |
| .I msg_qbytes |
| setting for subsequently created message queues. |
| The |
| .I msg_qbytes |
| setting specifies the maximum number of bytes that may be written to the |
| message queue. |
| .TP |
| .IR /proc/sys/kernel/ngroups_max " (since Linux 2.6.4)" |
| This is a read-only file that displays the upper limit on the |
| number of a process's group memberships. |
| .TP |
| .IR /proc/sys/kernel/ns_last_pid " (since Linux 3.3)" |
| See |
| .BR pid_namespaces (7). |
| .TP |
| .IR /proc/sys/kernel/ostype " and " /proc/sys/kernel/osrelease |
| These files |
| give substrings of |
| .IR /proc/version . |
| .TP |
| .IR /proc/sys/kernel/overflowgid " and " /proc/sys/kernel/overflowuid |
| These files duplicate the files |
| .I /proc/sys/fs/overflowgid |
| and |
| .IR /proc/sys/fs/overflowuid . |
| .TP |
| .I /proc/sys/kernel/panic |
| This file gives read/write access to the kernel variable |
| .IR panic_timeout . |
| If this is zero, the kernel will loop on a panic; if nonzero, |
| it indicates that the kernel should autoreboot after this number |
| of seconds. |
| When you use the |
| software watchdog device driver, the recommended setting is 60. |
| .TP |
| .IR /proc/sys/kernel/panic_on_oops " (since Linux 2.5.68)" |
| This file controls the kernel's behavior when an oops |
| or BUG is encountered. |
| If this file contains 0, then the system |
| tries to continue operation. |
| If it contains 1, then the system |
| delays a few seconds (to give klogd time to record the oops output) |
| and then panics. |
| If the |
| .I /proc/sys/kernel/panic |
| file is also nonzero, then the machine will be rebooted. |
| .TP |
| .IR /proc/sys/kernel/pid_max " (since Linux 2.5.34)" |
| This file specifies the value at which PIDs wrap around |
| (i.e., the value in this file is one greater than the maximum PID). |
| PIDs greater than this value are not allocated; |
| thus, the value in this file also acts as a system-wide limit |
| on the total number of processes and threads. |
| The default value for this file, 32768, |
| results in the same range of PIDs as on earlier kernels. |
| On 32-bit platforms, 32768 is the maximum value for |
| .IR pid_max . |
| On 64-bit systems, |
| .I pid_max |
| can be set to any value up to 2^22 |
| .RB ( PID_MAX_LIMIT , |
| approximately 4 million). |
| .\" Prior to 2.6.10, pid_max could also be raised above 32768 on 32-bit |
| .\" platforms, but this broke /proc/[pid] |
| .\" See http://marc.theaimsgroup.com/?l=linux-kernel&m=109513010926152&w=2 |
| .TP |
| .IR /proc/sys/kernel/powersave\-nap " (PowerPC only)" |
| This file contains a flag. |
| If set, Linux-PPC will use the "nap" mode of |
| powersaving, |
| otherwise the "doze" mode will be used. |
| .TP |
| .I /proc/sys/kernel/printk |
| See |
| .BR syslog (2). |
| .TP |
| .IR /proc/sys/kernel/pty " (since Linux 2.6.4)" |
| This directory contains two files relating to the number of UNIX 98 |
| pseudoterminals (see |
| .BR pts (4)) |
| on the system. |
| .TP |
| .I /proc/sys/kernel/pty/max |
| This file defines the maximum number of pseudoterminals. |
| .\" FIXME Document /proc/sys/kernel/pty/reserve |
| .\" New in Linux 3.3 |
| .\" commit e9aba5158a80098447ff207a452a3418ae7ee386 |
| .TP |
| .I /proc/sys/kernel/pty/nr |
| This read-only file |
| indicates how many pseudoterminals are currently in use. |
| .TP |
| .I /proc/sys/kernel/random |
| This directory |
| contains various parameters controlling the operation of the file |
| .IR /dev/random . |
| See |
| .BR random (4) |
| for further information. |
| .TP |
| .IR /proc/sys/kernel/random/uuid " (since Linux 2.4)" |
| Each read from this read-only file returns a randomly generated 128-bit UUID, |
| as a string in the standard UUID format. |
| .TP |
| .IR /proc/sys/kernel/randomize_va_space " (since Linux 2.6.12)" |
| .\" Some further details can be found in Documentation/sysctl/kernel.txt |
| Select the address space layout randomization (ASLR) policy for the system |
| (on architectures that support ASLR). |
| Three values are supported for this file: |
| .RS |
| .IP 0 3 |
| Turn ASLR off. |
| This is the default for architectures that don't support ASLR, |
| and when the kernel is booted with the |
| .I norandmaps |
| parameter. |
| .IP 1 |
| Make the addresses of |
| .BR mmap (2) |
| allocations, the stack, and the VDSO page randomized. |
| Among other things, this means that shared libraries will be |
| loaded at randomized addresses. |
| The text segment of PIE-linked binaries will also be loaded |
| at a randomized address. |
| This value is the default if the kernel was configured with |
| .BR CONFIG_COMPAT_BRK . |
| .IP 2 |
| (Since Linux 2.6.25) |
| .\" commit c1d171a002942ea2d93b4fbd0c9583c56fce0772 |
| Also support heap randomization. |
| This value is the default if the kernel was not configured with |
| .BR CONFIG_COMPAT_BRK . |
| .RE |
| .TP |
| .I /proc/sys/kernel/real\-root\-dev |
| This file is documented in the Linux kernel source file |
| .I Documentation/admin\-guide/initrd.rst |
| .\" commit 9d85025b0418163fae079c9ba8f8445212de8568 |
| (or |
| .I Documentation/initrd.txt |
| before Linux 4.10). |
| .TP |
| .IR /proc/sys/kernel/reboot\-cmd " (Sparc only)" |
| This file seems to be a way to give an argument to the SPARC |
| ROM/Flash boot loader. |
| Maybe to tell it what to do after |
| rebooting? |
| .TP |
| .I /proc/sys/kernel/rtsig\-max |
| (Only in kernels up to and including 2.6.7; see |
| .BR setrlimit (2)) |
| This file can be used to tune the maximum number |
| of POSIX real-time (queued) signals that can be outstanding |
| in the system. |
| .TP |
| .I /proc/sys/kernel/rtsig\-nr |
| (Only in kernels up to and including 2.6.7.) |
| This file shows the number of POSIX real-time signals currently queued. |
| .TP |
| .IR /proc/[pid]/sched_autogroup_enabled " (since Linux 2.6.38)" |
| .\" commit 5091faa449ee0b7d73bc296a93bca9540fc51d0a |
| See |
| .BR sched (7). |
| .TP |
| .IR /proc/sys/kernel/sched_child_runs_first " (since Linux 2.6.23)" |
| If this file contains the value zero, then, after a |
| .BR fork (2), |
| the parent is first scheduled on the CPU. |
| If the file contains a nonzero value, |
| then the child is scheduled first on the CPU. |
| (Of course, on a multiprocessor system, |
| the parent and the child might both immediately be scheduled on a CPU.) |
| .TP |
| .IR /proc/sys/kernel/sched_rr_timeslice_ms " (since Linux 3.9)" |
| See |
| .BR sched_rr_get_interval (2). |
| .TP |
| .IR /proc/sys/kernel/sched_rt_period_us " (since Linux 2.6.25)" |
| See |
| .BR sched (7). |
| .TP |
| .IR /proc/sys/kernel/sched_rt_runtime_us " (since Linux 2.6.25)" |
| See |
| .BR sched (7). |
| .TP |
| .IR /proc/sys/kernel/seccomp " (since Linux 4.14)" |
| .\" commit 8e5f1ad116df6b0de65eac458d5e7c318d1c05af |
| This directory provides additional seccomp information and |
| configuration. |
| See |
| .BR seccomp (2) |
| for further details. |
| .TP |
| .IR /proc/sys/kernel/sem " (since Linux 2.4)" |
| This file contains 4 numbers defining limits for System V IPC semaphores. |
| These fields are, in order: |
| .RS |
| .IP SEMMSL 8 |
| The maximum semaphores per semaphore set. |
| .IP SEMMNS 8 |
| A system-wide limit on the number of semaphores in all semaphore sets. |
| .IP SEMOPM 8 |
| The maximum number of operations that may be specified in a |
| .BR semop (2) |
| call. |
| .IP SEMMNI 8 |
| A system-wide limit on the maximum number of semaphore identifiers. |
| .RE |
| .TP |
| .I /proc/sys/kernel/sg\-big\-buff |
| This file |
| shows the size of the generic SCSI device (sg) buffer. |
| You can't tune it just yet, but you could change it at |
| compile time by editing |
| .I include/scsi/sg.h |
| and changing |
| the value of |
| .BR SG_BIG_BUFF . |
| However, there shouldn't be any reason to change this value. |
| .TP |
| .IR /proc/sys/kernel/shm_rmid_forced " (since Linux 3.1)" |
| .\" commit b34a6b1da371ed8af1221459a18c67970f7e3d53 |
| .\" See also Documentation/sysctl/kernel.txt |
| If this file is set to 1, all System V shared memory segments will |
| be marked for destruction as soon as the number of attached processes |
| falls to zero; |
| in other words, it is no longer possible to create shared memory segments |
| that exist independently of any attached process. |
| .IP |
| The effect is as though a |
| .BR shmctl (2) |
| .B IPC_RMID |
| is performed on all existing segments as well as all segments |
| created in the future (until this file is reset to 0). |
| Note that existing segments that are attached to no process will be |
| immediately destroyed when this file is set to 1. |
| Setting this option will also destroy segments that were created, |
| but never attached, |
| upon termination of the process that created the segment with |
| .BR shmget (2). |
| .IP |
| Setting this file to 1 provides a way of ensuring that |
| all System V shared memory segments are counted against the |
| resource usage and resource limits (see the description of |
| .B RLIMIT_AS |
| in |
| .BR getrlimit (2)) |
| of at least one process. |
| .IP |
| Because setting this file to 1 produces behavior that is nonstandard |
| and could also break existing applications, |
| the default value in this file is 0. |
| Set this file to 1 only if you have a good understanding |
| of the semantics of the applications using |
| System V shared memory on your system. |
| .TP |
| .IR /proc/sys/kernel/shmall " (since Linux 2.2)" |
| This file |
| contains the system-wide limit on the total number of pages of |
| System V shared memory. |
| .TP |
| .IR /proc/sys/kernel/shmmax " (since Linux 2.2)" |
| This file |
| can be used to query and set the run-time limit |
| on the maximum (System V IPC) shared memory segment size that can be |
| created. |
| Shared memory segments up to 1 GB are now supported in the |
| kernel. |
| This value defaults to |
| .BR SHMMAX . |
| .TP |
| .IR /proc/sys/kernel/shmmni " (since Linux 2.4)" |
| This file |
| specifies the system-wide maximum number of System V shared memory |
| segments that can be created. |
| .TP |
| .IR /proc/sys/kernel/sysctl_writes_strict " (since Linux 3.16)" |
| .\" commit f88083005ab319abba5d0b2e4e997558245493c8 |
| .\" commit 2ca9bb456ada8bcbdc8f77f8fc78207653bbaa92 |
| .\" commit f4aacea2f5d1a5f7e3154e967d70cf3f711bcd61 |
| .\" commit 24fe831c17ab8149413874f2fd4e5c8a41fcd294 |
| The value in this file determines how the file offset affects |
| the behavior of updating entries in files under |
| .IR /proc/sys . |
| The file has three possible values: |
| .RS |
| .TP 4 |
| \-1 |
| This provides legacy handling, with no printk warnings. |
| Each |
| .BR write (2) |
| must fully contain the value to be written, |
| and multiple writes on the same file descriptor |
| will overwrite the entire value, regardless of the file position. |
| .TP |
| 0 |
| (default) This provides the same behavior as for \-1, |
| but printk warnings are written for processes that |
| perform writes when the file offset is not 0. |
| .TP |
| 1 |
| Respect the file offset when writing strings into |
| .I /proc/sys |
| files. |
| Multiple writes will |
| .I append |
| to the value buffer. |
| Anything written beyond the maximum length |
| of the value buffer will be ignored. |
| Writes to numeric |
| .I /proc/sys |
| entries must always be at file offset 0 and the value must be |
| fully contained in the buffer provided to |
| .BR write (2). |
| .\" FIXME . |
| .\" With /proc/sys/kernel/sysctl_writes_strict==1, writes at an |
| .\" offset other than 0 do not generate an error. Instead, the |
| .\" write() succeeds, but the file is left unmodified. |
| .\" This is surprising. The behavior may change in the future. |
| .\" See thread.gmane.org/gmane.linux.man/9197 |
| .\" From: Michael Kerrisk (man-pages <mtk.manpages@...> |
| .\" Subject: sysctl_writes_strict documentation + an oddity? |
| .\" Newsgroups: gmane.linux.man, gmane.linux.kernel |
| .\" Date: 2015-05-09 08:54:11 GMT |
| .RE |
| .TP |
| .I /proc/sys/kernel/sysrq |
| This file controls the functions allowed to be invoked by the SysRq key. |
| By default, |
| the file contains 1 meaning that every possible SysRq request is allowed |
| (in older kernel versions, SysRq was disabled by default, |
| and you were required to specifically enable it at run-time, |
| but this is not the case any more). |
| Possible values in this file are: |
| .RS |
| .TP 5 |
| 0 |
| Disable sysrq completely |
| .TP |
| 1 |
| Enable all functions of sysrq |
| .TP |
| > 1 |
| Bit mask of allowed sysrq functions, as follows: |
| .PD 0 |
| .RS |
| .TP 5 |
| \ \ 2 |
| Enable control of console logging level |
| .TP |
| \ \ 4 |
| Enable control of keyboard (SAK, unraw) |
| .TP |
| \ \ 8 |
| Enable debugging dumps of processes etc. |
| .TP |
| \ 16 |
| Enable sync command |
| .TP |
| \ 32 |
| Enable remount read-only |
| .TP |
| \ 64 |
| Enable signaling of processes (term, kill, oom-kill) |
| .TP |
| 128 |
| Allow reboot/poweroff |
| .TP |
| 256 |
| Allow nicing of all real-time tasks |
| .RE |
| .PD |
| .RE |
| .IP |
| This file is present only if the |
| .B CONFIG_MAGIC_SYSRQ |
| kernel configuration option is enabled. |
| For further details see the Linux kernel source file |
| .I Documentation/admin\-guide/sysrq.rst |
| .\" commit 9d85025b0418163fae079c9ba8f8445212de8568 |
| (or |
| .I Documentation/sysrq.txt |
| before Linux 4.10). |
| .TP |
| .I /proc/sys/kernel/version |
| This file contains a string such as: |
| .IP |
| #5 Wed Feb 25 21:49:24 MET 1998 |
| .IP |
| The "#5" means that |
| this is the fifth kernel built from this source base and the |
| date following it indicates the time the kernel was built. |
| .TP |
| .IR /proc/sys/kernel/threads\-max " (since Linux 2.3.11)" |
| .\" The following is based on Documentation/sysctl/kernel.txt |
| This file specifies the system-wide limit on the number of |
| threads (tasks) that can be created on the system. |
| .IP |
| Since Linux 4.1, |
| .\" commit 230633d109e35b0a24277498e773edeb79b4a331 |
| the value that can be written to |
| .I threads\-max |
| is bounded. |
| The minimum value that can be written is 20. |
| The maximum value that can be written is given by the |
| constant |
| .B FUTEX_TID_MASK |
| (0x3fffffff). |
| If a value outside of this range is written to |
| .IR threads\-max , |
| the error |
| .B EINVAL |
| occurs. |
| .IP |
| The value written is checked against the available RAM pages. |
| If the thread structures would occupy too much (more than 1/8th) |
| of the available RAM pages, |
| .I threads\-max |
| is reduced accordingly. |
| .TP |
| .IR /proc/sys/kernel/yama/ptrace_scope " (since Linux 3.5)" |
| See |
| .BR ptrace (2). |
| .TP |
| .IR /proc/sys/kernel/zero\-paged " (PowerPC only)" |
| This file |
| contains a flag. |
| When enabled (nonzero), Linux-PPC will pre-zero pages in |
| the idle loop, possibly speeding up get_free_pages. |
| .TP |
| .I /proc/sys/net |
| This directory contains networking stuff. |
| Explanations for some of the files under this directory can be found in |
| .BR tcp (7) |
| and |
| .BR ip (7). |
| .TP |
| .I /proc/sys/net/core/bpf_jit_enable |
| See |
| .BR bpf (2). |
| .TP |
| .I /proc/sys/net/core/somaxconn |
| This file defines a ceiling value for the |
| .I backlog |
| argument of |
| .BR listen (2); |
| see the |
| .BR listen (2) |
| manual page for details. |
| .TP |
| .I /proc/sys/proc |
| This directory may be empty. |
| .TP |
| .I /proc/sys/sunrpc |
| This directory supports Sun remote procedure call for network filesystem |
| (NFS). |
| On some systems, it is not present. |
| .TP |
| .IR /proc/sys/user " (since Linux 4.9)" |
| See |
| .BR namespaces (7). |
| .TP |
| .I /proc/sys/vm |
| This directory contains files for memory management tuning, buffer and |
| cache management. |
| .TP |
| .IR /proc/sys/vm/admin_reserve_kbytes " (since Linux 3.10)" |
| .\" commit 4eeab4f5580d11bffedc697684b91b0bca0d5009 |
| This file defines the amount of free memory (in KiB) on the system that |
| should be reserved for users with the capability |
| .BR CAP_SYS_ADMIN . |
| .IP |
| The default value in this file is the minimum of [3% of free pages, 8MiB] |
| expressed as KiB. |
| The default is intended to provide enough for the superuser |
| to log in and kill a process, if necessary, |
| under the default overcommit 'guess' mode (i.e., 0 in |
| .IR /proc/sys/vm/overcommit_memory ). |
| .IP |
| Systems running in "overcommit never" mode (i.e., 2 in |
| .IR /proc/sys/vm/overcommit_memory ) |
| should increase the value in this file to account |
| for the full virtual memory size of the programs used to recover (e.g., |
| .BR login (1) |
| .BR ssh (1), |
| and |
| .BR top (1)) |
| Otherwise, the superuser may not be able to log in to recover the system. |
| For example, on x86-64 a suitable value is 131072 (128MiB reserved). |
| .IP |
| Changing the value in this file takes effect whenever |
| an application requests memory. |
| .TP |
| .IR /proc/sys/vm/compact_memory " (since Linux 2.6.35)" |
| When 1 is written to this file, all zones are compacted such that free |
| memory is available in contiguous blocks where possible. |
| The effect of this action can be seen by examining |
| .IR /proc/buddyinfo . |
| .IP |
| Present only if the kernel was configured with |
| .BR CONFIG_COMPACTION . |
| .TP |
| .IR /proc/sys/vm/drop_caches " (since Linux 2.6.16)" |
| Writing to this file causes the kernel to drop clean caches, dentries, and |
| inodes from memory, causing that memory to become free. |
| This can be useful for memory management testing and |
| performing reproducible filesystem benchmarks. |
| Because writing to this file causes the benefits of caching to be lost, |
| it can degrade overall system performance. |
| .IP |
| To free pagecache, use: |
| .IP |
| echo 1 > /proc/sys/vm/drop_caches |
| .IP |
| To free dentries and inodes, use: |
| .IP |
| echo 2 > /proc/sys/vm/drop_caches |
| .IP |
| To free pagecache, dentries and inodes, use: |
| .IP |
| echo 3 > /proc/sys/vm/drop_caches |
| .IP |
| Because writing to this file is a nondestructive operation and dirty objects |
| are not freeable, the |
| user should run |
| .BR sync (1) |
| first. |
| .TP |
| .IR /proc/sys/vm/legacy_va_layout " (since Linux 2.6.9)" |
| .\" The following is from Documentation/filesystems/proc.txt |
| If nonzero, this disables the new 32-bit memory-mapping layout; |
| the kernel will use the legacy (2.4) layout for all processes. |
| .TP |
| .IR /proc/sys/vm/memory_failure_early_kill " (since Linux 2.6.32)" |
| .\" The following is based on the text in Documentation/sysctl/vm.txt |
| Control how to kill processes when an uncorrected memory error |
| (typically a 2-bit error in a memory module) |
| that cannot be handled by the kernel |
| is detected in the background by hardware. |
| In some cases (like the page still having a valid copy on disk), |
| the kernel will handle the failure |
| transparently without affecting any applications. |
| But if there is no other up-to-date copy of the data, |
| it will kill processes to prevent any data corruptions from propagating. |
| .IP |
| The file has one of the following values: |
| .RS |
| .IP 1: 4 |
| Kill all processes that have the corrupted-and-not-reloadable page mapped |
| as soon as the corruption is detected. |
| Note that this is not supported for a few types of pages, |
| such as kernel internally |
| allocated data or the swap cache, but works for the majority of user pages. |
| .IP 0: 4 |
| Unmap the corrupted page from all processes and kill a process |
| only if it tries to access the page. |
| .RE |
| .IP |
| The kill is performed using a |
| .B SIGBUS |
| signal with |
| .I si_code |
| set to |
| .BR BUS_MCEERR_AO . |
| Processes can handle this if they want to; see |
| .BR sigaction (2) |
| for more details. |
| .IP |
| This feature is active only on architectures/platforms with advanced machine |
| check handling and depends on the hardware capabilities. |
| .IP |
| Applications can override the |
| .I memory_failure_early_kill |
| setting individually with the |
| .BR prctl (2) |
| .B PR_MCE_KILL |
| operation. |
| .IP |
| Present only if the kernel was configured with |
| .BR CONFIG_MEMORY_FAILURE . |
| .TP |
| .IR /proc/sys/vm/memory_failure_recovery " (since Linux 2.6.32)" |
| .\" The following is based on the text in Documentation/sysctl/vm.txt |
| Enable memory failure recovery (when supported by the platform). |
| .RS |
| .IP 1: 4 |
| Attempt recovery. |
| .IP 0: 4 |
| Always panic on a memory failure. |
| .RE |
| .IP |
| Present only if the kernel was configured with |
| .BR CONFIG_MEMORY_FAILURE . |
| .TP |
| .IR /proc/sys/vm/oom_dump_tasks " (since Linux 2.6.25)" |
| .\" The following is from Documentation/sysctl/vm.txt |
| Enables a system-wide task dump (excluding kernel threads) to be |
| produced when the kernel performs an OOM-killing. |
| The dump includes the following information |
| for each task (thread, process): |
| thread ID, real user ID, thread group ID (process ID), |
| virtual memory size, resident set size, |
| the CPU that the task is scheduled on, |
| oom_adj score (see the description of |
| .IR /proc/[pid]/oom_adj ), |
| and command name. |
| This is helpful to determine why the OOM-killer was invoked |
| and to identify the rogue task that caused it. |
| .IP |
| If this contains the value zero, this information is suppressed. |
| On very large systems with thousands of tasks, |
| it may not be feasible to dump the memory state information for each one. |
| Such systems should not be forced to incur a performance penalty in |
| OOM situations when the information may not be desired. |
| .IP |
| If this is set to nonzero, this information is shown whenever the |
| OOM-killer actually kills a memory-hogging task. |
| .IP |
| The default value is 0. |
| .TP |
| .IR /proc/sys/vm/oom_kill_allocating_task " (since Linux 2.6.24)" |
| .\" The following is from Documentation/sysctl/vm.txt |
| This enables or disables killing the OOM-triggering task in |
| out-of-memory situations. |
| .IP |
| If this is set to zero, the OOM-killer will scan through the entire |
| tasklist and select a task based on heuristics to kill. |
| This normally selects a rogue memory-hogging task that |
| frees up a large amount of memory when killed. |
| .IP |
| If this is set to nonzero, the OOM-killer simply kills the task that |
| triggered the out-of-memory condition. |
| This avoids a possibly expensive tasklist scan. |
| .IP |
| If |
| .I /proc/sys/vm/panic_on_oom |
| is nonzero, it takes precedence over whatever value is used in |
| .IR /proc/sys/vm/oom_kill_allocating_task . |
| .IP |
| The default value is 0. |
| .TP |
| .IR /proc/sys/vm/overcommit_kbytes " (since Linux 3.14)" |
| .\" commit 49f0ce5f92321cdcf741e35f385669a421013cb7 |
| This writable file provides an alternative to |
| .IR /proc/sys/vm/overcommit_ratio |
| for controlling the |
| .I CommitLimit |
| when |
| .IR /proc/sys/vm/overcommit_memory |
| has the value 2. |
| It allows the amount of memory overcommitting to be specified as |
| an absolute value (in kB), |
| rather than as a percentage, as is done with |
| .IR overcommit_ratio . |
| This allows for finer-grained control of |
| .IR CommitLimit |
| on systems with extremely large memory sizes. |
| .IP |
| Only one of |
| .IR overcommit_kbytes |
| or |
| .IR overcommit_ratio |
| can have an effect: |
| if |
| .IR overcommit_kbytes |
| has a nonzero value, then it is used to calculate |
| .IR CommitLimit , |
| otherwise |
| .IR overcommit_ratio |
| is used. |
| Writing a value to either of these files causes the |
| value in the other file to be set to zero. |
| .TP |
| .I /proc/sys/vm/overcommit_memory |
| This file contains the kernel virtual memory accounting mode. |
| Values are: |
| .RS |
| .IP |
| 0: heuristic overcommit (this is the default) |
| .br |
| 1: always overcommit, never check |
| .br |
| 2: always check, never overcommit |
| .RE |
| .IP |
| In mode 0, calls of |
| .BR mmap (2) |
| with |
| .B MAP_NORESERVE |
| are not checked, and the default check is very weak, |
| leading to the risk of getting a process "OOM-killed". |
| .IP |
| In mode 1, the kernel pretends there is always enough memory, |
| until memory actually runs out. |
| One use case for this mode is scientific computing applications |
| that employ large sparse arrays. |
| In Linux kernel versions before 2.6.0, any nonzero value implies mode 1. |
| .IP |
| In mode 2 (available since Linux 2.6), the total virtual address space |
| that can be allocated |
| .RI ( CommitLimit |
| in |
| .IR /proc/meminfo ) |
| is calculated as |
| .IP |
| CommitLimit = (total_RAM \- total_huge_TLB) * |
| overcommit_ratio / 100 + total_swap |
| .IP |
| where: |
| .RS 12 |
| .IP * 3 |
| .I total_RAM |
| is the total amount of RAM on the system; |
| .IP * |
| .I total_huge_TLB |
| is the amount of memory set aside for huge pages; |
| .IP * |
| .I overcommit_ratio |
| is the value in |
| .IR /proc/sys/vm/overcommit_ratio ; |
| and |
| .IP * |
| .I total_swap |
| is the amount of swap space. |
| .RE |
| .IP |
| For example, on a system with 16 GB of physical RAM, 16 GB |
| of swap, no space dedicated to huge pages, and an |
| .I overcommit_ratio |
| of 50, this formula yields a |
| .I CommitLimit |
| of 24 GB. |
| .IP |
| Since Linux 3.14, if the value in |
| .I /proc/sys/vm/overcommit_kbytes |
| is nonzero, then |
| .I CommitLimit |
| is instead calculated as: |
| .IP |
| CommitLimit = overcommit_kbytes + total_swap |
| .IP |
| See also the description of |
| .IR /proc/sys/vm/admin_reserve_kbytes |
| and |
| .IR /proc/sys/vm/user_reserve_kbytes . |
| .TP |
| .IR /proc/sys/vm/overcommit_ratio " (since Linux 2.6.0)" |
| This writable file defines a percentage by which memory |
| can be overcommitted. |
| The default value in the file is 50. |
| See the description of |
| .IR /proc/sys/vm/overcommit_memory . |
| .TP |
| .IR /proc/sys/vm/panic_on_oom " (since Linux 2.6.18)" |
| .\" The following is adapted from Documentation/sysctl/vm.txt |
| This enables or disables a kernel panic in |
| an out-of-memory situation. |
| .IP |
| If this file is set to the value 0, |
| the kernel's OOM-killer will kill some rogue process. |
| Usually, the OOM-killer is able to kill a rogue process and the |
| system will survive. |
| .IP |
| If this file is set to the value 1, |
| then the kernel normally panics when out-of-memory happens. |
| However, if a process limits allocations to certain nodes |
| using memory policies |
| .RB ( mbind (2) |
| .BR MPOL_BIND ) |
| or cpusets |
| .RB ( cpuset (7)) |
| and those nodes reach memory exhaustion status, |
| one process may be killed by the OOM-killer. |
| No panic occurs in this case: |
| because other nodes' memory may be free, |
| this means the system as a whole may not have reached |
| an out-of-memory situation yet. |
| .IP |
| If this file is set to the value 2, |
| the kernel always panics when an out-of-memory condition occurs. |
| .IP |
| The default value is 0. |
| 1 and 2 are for failover of clustering. |
| Select either according to your policy of failover. |
| .TP |
| .IR /proc/sys/vm/swappiness |
| .\" The following is from Documentation/sysctl/vm.txt |
| The value in this file controls how aggressively the kernel will swap |
| memory pages. |
| Higher values increase aggressiveness, lower values |
| decrease aggressiveness. |
| The default value is 60. |
| .TP |
| .IR /proc/sys/vm/user_reserve_kbytes " (since Linux 3.10)" |
| .\" commit c9b1d0981fcce3d9976d7b7a56e4e0503bc610dd |
| Specifies an amount of memory (in KiB) to reserve for user processes. |
| This is intended to prevent a user from starting a single memory hogging |
| process, such that they cannot recover (kill the hog). |
| The value in this file has an effect only when |
| .IR /proc/sys/vm/overcommit_memory |
| is set to 2 ("overcommit never" mode). |
| In this case, the system reserves an amount of memory that is the minimum |
| of [3% of current process size, |
| .IR user_reserve_kbytes ]. |
| .IP |
| The default value in this file is the minimum of [3% of free pages, 128MiB] |
| expressed as KiB. |
| .IP |
| If the value in this file is set to zero, |
| then a user will be allowed to allocate all free memory with a single process |
| (minus the amount reserved by |
| .IR /proc/sys/vm/admin_reserve_kbytes ). |
| Any subsequent attempts to execute a command will result in |
| "fork: Cannot allocate memory". |
| .IP |
| Changing the value in this file takes effect whenever |
| an application requests memory. |
| .TP |
| .IR /proc/sys/vm/unprivileged_userfaultfd " (since Linux 5.2)" |
| .\" cefdca0a86be517bc390fc4541e3674b8e7803b0 |
| This (writable) file exposes a flag that controls whether |
| unprivileged processes are allowed to employ |
| .BR userfaultfd (2). |
| If this file has the value 1, then unprivileged processes may use |
| .BR userfaultfd (2). |
| If this file has the value 0, then only processes that have the |
| .B CAP_SYS_PTRACE |
| capability may employ |
| .BR userfaultfd (2). |
| The default value in this file is 1. |
| .TP |
| .IR /proc/sysrq\-trigger " (since Linux 2.4.21)" |
| Writing a character to this file triggers the same SysRq function as |
| typing ALT-SysRq-<character> (see the description of |
| .IR /proc/sys/kernel/sysrq ). |
| This file is normally writable only by |
| .IR root . |
| For further details see the Linux kernel source file |
| .I Documentation/admin\-guide/sysrq.rst |
| .\" commit 9d85025b0418163fae079c9ba8f8445212de8568 |
| (or |
| .I Documentation/sysrq.txt |
| before Linux 4.10). |
| .TP |
| .I /proc/sysvipc |
| Subdirectory containing the pseudo-files |
| .IR msg ", " sem " and " shm "." |
| These files list the System V Interprocess Communication (IPC) objects |
| (respectively: message queues, semaphores, and shared memory) |
| that currently exist on the system, |
| providing similar information to that available via |
| .BR ipcs (1). |
| These files have headers and are formatted (one IPC object per line) |
| for easy understanding. |
| .BR sysvipc (7) |
| provides further background on the information shown by these files. |
| .TP |
| .IR /proc/thread\-self " (since Linux 3.17)" |
| .\" commit 0097875bd41528922fb3bb5f348c53f17e00e2fd |
| This directory refers to the thread accessing the |
| .I /proc |
| filesystem, |
| and is identical to the |
| .I /proc/self/task/[tid] |
| directory named by the process thread ID |
| .RI ( [tid] ) |
| of the same thread. |
| .TP |
| .IR /proc/timer_list " (since Linux 2.6.21)" |
| .\" commit 289f480af87e45f7a6de6ba9b4c061c2e259fe98 |
| This read-only file exposes a list of all currently pending |
| (high-resolution) timers, |
| all clock-event sources, and their parameters in a human-readable form. |
| .TP |
| .IR /proc/timer_stats " (from Linux 2.6.21 until Linux 4.10)" |
| .\" commit 82f67cd9fca8c8762c15ba7ed0d5747588c1e221 |
| .\" Date: Fri Feb 16 01:28:13 2007 -0800 |
| .\" Text largely derived from Documentation/timers/timer_stats.txt |
| .\" removed in commit dfb4357da6ddbdf57d583ba64361c9d792b0e0b1 |
| .\" Date: Wed Feb 8 11:26:59 2017 -0800 |
| This is a debugging facility to make timer (ab)use in a Linux |
| system visible to kernel and user-space developers. |
| It can be used by kernel and user-space developers to verify that |
| their code does not make undue use of timers. |
| The goal is to avoid unnecessary wakeups, |
| thereby optimizing power consumption. |
| .IP |
| If enabled in the kernel |
| .RB ( CONFIG_TIMER_STATS ), |
| but not used, |
| it has almost zero run-time overhead and a relatively small |
| data-structure overhead. |
| Even if collection is enabled at run time, overhead is low: |
| all the locking is per-CPU and lookup is hashed. |
| .IP |
| The |
| .I /proc/timer_stats |
| file is used both to control sampling facility and to read out the |
| sampled information. |
| .IP |
| The |
| .I timer_stats |
| functionality is inactive on bootup. |
| A sampling period can be started using the following command: |
| .IP |
| .in +4n |
| .EX |
| # echo 1 > /proc/timer_stats |
| .EE |
| .in |
| .IP |
| The following command stops a sampling period: |
| .IP |
| .in +4n |
| .EX |
| # echo 0 > /proc/timer_stats |
| .EE |
| .in |
| .IP |
| The statistics can be retrieved by: |
| .IP |
| .in +4n |
| .EX |
| $ cat /proc/timer_stats |
| .EE |
| .in |
| .IP |
| While sampling is enabled, each readout from |
| .I /proc/timer_stats |
| will see |
| newly updated statistics. |
| Once sampling is disabled, the sampled information |
| is kept until a new sample period is started. |
| This allows multiple readouts. |
| .IP |
| Sample output from |
| .IR /proc/timer_stats : |
| .IP |
| .in +4n |
| .EX |
| .RB $ " cat /proc/timer_stats" |
| Timer Stats Version: v0.3 |
| Sample period: 1.764 s |
| Collection: active |
| 255, 0 swapper/3 hrtimer_start_range_ns (tick_sched_timer) |
| 71, 0 swapper/1 hrtimer_start_range_ns (tick_sched_timer) |
| 58, 0 swapper/0 hrtimer_start_range_ns (tick_sched_timer) |
| 4, 1694 gnome\-shell mod_delayed_work_on (delayed_work_timer_fn) |
| 17, 7 rcu_sched rcu_gp_kthread (process_timeout) |
| \&... |
| 1, 4911 kworker/u16:0 mod_delayed_work_on (delayed_work_timer_fn) |
| 1D, 2522 kworker/0:0 queue_delayed_work_on (delayed_work_timer_fn) |
| 1029 total events, 583.333 events/sec |
| .EE |
| .in |
| .IP |
| The output columns are: |
| .RS |
| .IP * 3 |
| a count of the number of events, |
| optionally (since Linux 2.6.23) followed by the letter \(aqD\(aq |
| .\" commit c5c061b8f9726bc2c25e19dec227933a13d1e6b7 deferrable timers |
| if this is a deferrable timer; |
| .IP * |
| the PID of the process that initialized the timer; |
| .IP * |
| the name of the process that initialized the timer; |
| .IP * |
| the function where the timer was initialized; and |
| .IP * |
| (in parentheses) |
| the callback function that is associated with the timer. |
| .RE |
| .IP |
| During the Linux 4.11 development cycle, |
| this file was removed because of security concerns, |
| as it exposes information across namespaces. |
| Furthermore, it is possible to obtain |
| the same information via in-kernel tracing facilities such as ftrace. |
| .TP |
| .I /proc/tty |
| Subdirectory containing the pseudo-files and subdirectories for |
| tty drivers and line disciplines. |
| .TP |
| .I /proc/uptime |
| This file contains two numbers (values in seconds): the uptime of the |
| system (including time spent in suspend) and the amount of time spent |
| in the idle process. |
| .TP |
| .I /proc/version |
| This string identifies the kernel version that is currently running. |
| It includes the contents of |
| .IR /proc/sys/kernel/ostype , |
| .I /proc/sys/kernel/osrelease |
| and |
| .IR /proc/sys/kernel/version . |
| For example: |
| .IP |
| .in +4n |
| .EX |
| Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994 |
| .EE |
| .in |
| .\" FIXME 2.6.13 seems to have /proc/vmcore implemented; document this |
| .\" See Documentation/kdump/kdump.txt |
| .\" commit 666bfddbe8b8fd4fd44617d6c55193d5ac7edb29 |
| .\" Needs CONFIG_VMCORE |
| .\" |
| .TP |
| .IR /proc/vmstat " (since Linux 2.6.0)" |
| This file displays various virtual memory statistics. |
| Each line of this file contains a single name-value pair, |
| delimited by white space. |
| Some lines are present only if the kernel was configured with |
| suitable options. |
| (In some cases, the options required for particular files have changed |
| across kernel versions, so they are not listed here. |
| Details can be found by consulting the kernel source code.) |
| The following fields may be present: |
| .\" FIXME We need explanations for each of the following fields... |
| .RS |
| .TP |
| .IR nr_free_pages " (since Linux 2.6.31)" |
| .\" commit d23ad42324cc4378132e51f2fc5c9ba6cbe75182 |
| .TP |
| .IR nr_alloc_batch " (since Linux 3.12)" |
| .\" commit 81c0a2bb515fd4daae8cab64352877480792b515 |
| .TP |
| .IR nr_inactive_anon " (since Linux 2.6.28)" |
| .\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db |
| .TP |
| .IR nr_active_anon " (since Linux 2.6.28)" |
| .\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db |
| .TP |
| .IR nr_inactive_file " (since Linux 2.6.28)" |
| .\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db |
| .TP |
| .IR nr_active_file " (since Linux 2.6.28)" |
| .\" commit 4f98a2fee8acdb4ac84545df98cccecfd130f8db |
| .TP |
| .IR nr_unevictable " (since Linux 2.6.28)" |
| .\" commit 7b854121eb3e5ba0241882ff939e2c485228c9c5 |
| .TP |
| .IR nr_mlock " (since Linux 2.6.28)" |
| .\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820 |
| .TP |
| .IR nr_anon_pages " (since Linux 2.6.18)" |
| .\" commit f3dbd34460ff54962d3e3244b6bcb7f5295356e6 |
| .TP |
| .IR nr_mapped " (since Linux 2.6.0)" |
| .TP |
| .IR nr_file_pages " (since Linux 2.6.18)" |
| .\" commit 347ce434d57da80fd5809c0c836f206a50999c26 |
| .TP |
| .IR nr_dirty " (since Linux 2.6.0)" |
| .TP |
| .IR nr_writeback " (since Linux 2.6.0)" |
| .TP |
| .IR nr_slab_reclaimable " (since Linux 2.6.19)" |
| .\" commit 972d1a7b140569084439a81265a0f15b74e924e0 |
| .\" Linux 2.6.0 had nr_slab |
| .TP |
| .IR nr_slab_unreclaimable " (since Linux 2.6.19)" |
| .\" commit 972d1a7b140569084439a81265a0f15b74e924e0 |
| .TP |
| .IR nr_page_table_pages " (since Linux 2.6.0)" |
| .TP |
| .IR nr_kernel_stack " (since Linux 2.6.32)" |
| .\" commit c6a7f5728a1db45d30df55a01adc130b4ab0327c |
| Amount of memory allocated to kernel stacks. |
| .TP |
| .IR nr_unstable " (since Linux 2.6.0)" |
| .TP |
| .IR nr_bounce " (since Linux 2.6.12)" |
| .\" commit edfbe2b0038723e5699ab22695ccd62b5542a5c1 |
| .TP |
| .IR nr_vmscan_write " (since Linux 2.6.19)" |
| .\" commit e129b5c23c2b471d47f1c5d2b8b193fc2034af43 |
| .TP |
| .IR nr_vmscan_immediate_reclaim " (since Linux 3.2)" |
| .\" commit 49ea7eb65e7c5060807fb9312b1ad4c3eab82e2c |
| .TP |
| .IR nr_writeback_temp " (since Linux 2.6.26)" |
| .\" commit fc3ba692a4d19019387c5acaea63131f9eab05dd |
| .TP |
| .IR nr_isolated_anon " (since Linux 2.6.32)" |
| .\" commit a731286de62294b63d8ceb3c5914ac52cc17e690 |
| .TP |
| .IR nr_isolated_file " (since Linux 2.6.32)" |
| .\" commit a731286de62294b63d8ceb3c5914ac52cc17e690 |
| .TP |
| .IR nr_shmem " (since Linux 2.6.32)" |
| .\" commit 4b02108ac1b3354a22b0d83c684797692efdc395 |
| Pages used by shmem and |
| .BR tmpfs (5). |
| .TP |
| .IR nr_dirtied " (since Linux 2.6.37)" |
| .\" commit ea941f0e2a8c02ae876cd73deb4e1557248f258c |
| .TP |
| .IR nr_written " (since Linux 2.6.37)" |
| .\" commit ea941f0e2a8c02ae876cd73deb4e1557248f258c |
| .TP |
| .IR nr_pages_scanned " (since Linux 3.17)" |
| .\" commit 0d5d823ab4e608ec7b52ac4410de4cb74bbe0edd |
| .TP |
| .IR numa_hit " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR numa_miss " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR numa_foreign " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR numa_interleave " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR numa_local " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR numa_other " (since Linux 2.6.18)" |
| .\" commit ca889e6c45e0b112cb2ca9d35afc66297519b5d5 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR workingset_refault " (since Linux 3.15)" |
| .\" commit a528910e12ec7ee203095eb1711468a66b9b60b0 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR workingset_activate " (since Linux 3.15)" |
| .\" commit a528910e12ec7ee203095eb1711468a66b9b60b0 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR workingset_nodereclaim " (since Linux 3.15)" |
| .\" commit 449dd6984d0e47643c04c807f609dd56d48d5bcc |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR nr_anon_transparent_hugepages " (since Linux 2.6.38)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR nr_free_cma " (since Linux 3.7)" |
| .\" commit d1ce749a0db12202b711d1aba1d29e823034648d |
| Number of free CMA (Contiguous Memory Allocator) pages. |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR nr_dirty_threshold " (since Linux 2.6.37)" |
| .\" commit 79da826aee6a10902ef411bc65864bd02102fa83 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR nr_dirty_background_threshold " (since Linux 2.6.37)" |
| .\" commit 79da826aee6a10902ef411bc65864bd02102fa83 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgpgin " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgpgout " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pswpin " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pswpout " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgalloc_dma " (since Linux 2.6.5)" |
| .\" Linux 2.6.0 had pgalloc |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgalloc_dma32 " (since Linux 2.6.16)" |
| .\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgalloc_normal " (since Linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgalloc_high " (since Linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgalloc_movable " (since Linux 2.6.23)" |
| .\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgfree " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgactivate " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgdeactivate " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgfault " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgmajfault " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgrefill_dma " (since Linux 2.6.5)" |
| .\" Linux 2.6.0 had pgrefill |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgrefill_dma32 " (since Linux 2.6.16)" |
| .\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgrefill_normal " (since Linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgrefill_high " (since Linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgrefill_movable " (since Linux 2.6.23)" |
| .\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .\" Formerly there were |
| .\" pgsteal_high |
| .\" pgsteal_normal |
| .\" pgsteal_dma32 |
| .\" pgsteal_dma |
| .\" These were split out into pgsteal_kswapd* and pgsteal_direct* |
| .\" in commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .TP |
| .IR pgsteal_kswapd_dma " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Linux 2.6.0 had pgsteal |
| .\" Present only if the kernel was configured with |
| .\" .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_kswapd_dma32 " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_kswapd_normal " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_kswapd_high " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgsteal_kswapd_movable " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_direct_dma |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_direct_dma32 " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_direct_normal " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgsteal_direct_high " (since Linux 3.4)" |
| .\" commit 904249aa68010c8e223263c922fcbb840a3f42e4 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgsteal_direct_movable " (since Linux 2.6.23)" |
| .\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_kswapd_dma |
| .\" Linux 2.6.0 had pgscan |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_kswapd_dma32 " (since Linux 2.6.16)" |
| .\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_kswapd_normal " (since Linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_kswapd_high |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgscan_kswapd_movable " (since Linux 2.6.23)" |
| .\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_direct_dma |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_direct_dma32 " (since Linux 2.6.16)" |
| .\" commit 9328b8faae922e52073785ed6c1eaa8565648a0e |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_direct_normal |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_direct_high |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HIGHMEM . |
| .TP |
| .IR pgscan_direct_movable " (since Linux 2.6.23)" |
| .\" commit 2a1e274acf0b1c192face19a4be7c12d4503eaaf |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgscan_direct_throttle " (since Linux 3.6)" |
| .\" commit 68243e76ee343d63c6cf76978588a885951e2818 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR zone_reclaim_failed " (since linux 2.6.31)" |
| .\" commit 24cf72518c79cdcda486ed26074ff8151291cf65 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA . |
| .TP |
| .IR pginodesteal " (since linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR slabs_scanned " (since linux 2.6.5)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR kswapd_inodesteal " (since linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR kswapd_low_wmark_hit_quickly " (since 2.6.33)" |
| .\" commit bb3ab596832b920c703d1aea1ce76d69c0f71fb7 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR kswapd_high_wmark_hit_quickly " (since 2.6.33)" |
| .\" commit bb3ab596832b920c703d1aea1ce76d69c0f71fb7 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pageoutrun " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR allocstall " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR pgrotated " (since Linux 2.6.0)" |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR drop_pagecache " (since Linux 3.15)" |
| .\" commit 5509a5d27b971a90b940e148ca9ca53312e4fa7a |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR drop_slab " (since Linux 3.15)" |
| .\" commit 5509a5d27b971a90b940e148ca9ca53312e4fa7a |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR numa_pte_updates " (since Linux 3.8)" |
| .\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING . |
| .TP |
| .IR numa_huge_pte_updates " (since Linux 3.13)" |
| .\" commit 72403b4a0fbdf433c1fe0127e49864658f6f6468 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING . |
| .TP |
| .IR numa_hint_faults " (since Linux 3.8)" |
| .\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING . |
| .TP |
| .IR numa_hint_faults_local " (since Linux 3.8)" |
| .\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING . |
| .TP |
| .IR numa_pages_migrated " (since Linux 3.8)" |
| .\" commit 03c5a6e16322c997bf8f264851bfa3f532ad515f |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING |
| .\" and |
| .\" .BR CONFIG_NUMA_BALANCING . |
| .TP |
| .IR pgmigrate_success " (since Linux 3.8)" |
| .\" commit 5647bc293ab15f66a7b1cda850c5e9d162a6c7c2 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_MIGRATION . |
| .TP |
| .IR pgmigrate_fail " (since Linux 3.8)" |
| .\" commit 5647bc293ab15f66a7b1cda850c5e9d162a6c7c2 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_MIGRATION . |
| .TP |
| .IR compact_migrate_scanned " (since Linux 3.8)" |
| .\" commit 397487db696cae0b026a474a5cd66f4e372995e6 |
| .\" Linux 3.8 dropped compact_blocks_moved, compact_pages_moved, and |
| .\" compact_pagemigrate_failed |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR compact_free_scanned " (since Linux 3.8)" |
| .\" commit 397487db696cae0b026a474a5cd66f4e372995e6 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR compact_isolated " (since Linux 3.8)" |
| .\" commit 397487db696cae0b026a474a5cd66f4e372995e6 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR compact_stall " (since Linux 2.6.35)" |
| .\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR compact_fail " (since Linux 2.6.35)" |
| .\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR compact_success " (since Linux 2.6.35)" |
| .\" commit 56de7263fcf3eb10c8dcdf8d59a9cec831795f3f |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_COMPACTION . |
| .TP |
| .IR htlb_buddy_alloc_success " (since Linux 2.6.26)" |
| .\" commit 3b1163006332302117b1b2acf226d4014ff46525 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HUGETLB_PAGE . |
| .TP |
| .IR htlb_buddy_alloc_fail " (since Linux 2.6.26)" |
| .\" commit 3b1163006332302117b1b2acf226d4014ff46525 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_HUGETLB_PAGE . |
| .TP |
| .IR unevictable_pgs_culled " (since Linux 2.6.28)" |
| .\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_scanned " (since Linux 2.6.28)" |
| .\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_rescued " (since Linux 2.6.28)" |
| .\" commit bbfd28eee9fbd73e780b19beb3dc562befbb94fa |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_mlocked " (since Linux 2.6.28)" |
| .\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_munlocked " (since Linux 2.6.28)" |
| .\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_cleared " (since Linux 2.6.28)" |
| .\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .TP |
| .IR unevictable_pgs_stranded " (since Linux 2.6.28)" |
| .\" commit 5344b7e648980cc2ca613ec03a56a8222ff48820 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS . |
| .\" Linux 3.7 removed unevictable_pgs_mlockfreed |
| .TP |
| .IR thp_fault_alloc " (since Linux 2.6.39)" |
| .\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_fault_fallback " (since Linux 2.6.39)" |
| .\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_collapse_alloc " (since Linux 2.6.39)" |
| .\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_collapse_alloc_failed " (since Linux 2.6.39)" |
| .\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_split " (since Linux 2.6.39)" |
| .\" commit 81ab4201fb7d91d6b0cd9ad5b4b16776e4bed145 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_zero_page_alloc " (since Linux 3.8)" |
| .\" commit d8a8e1f0da3d29d7268b3300c96a059d63901b76 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR thp_zero_page_alloc_failed " (since Linux 3.8)" |
| .\" commit d8a8e1f0da3d29d7268b3300c96a059d63901b76 |
| See the kernel source file |
| .IR Documentation/admin\-guide/mm/transhuge.rst . |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_TRANSPARENT_HUGEPAGE . |
| .TP |
| .IR balloon_inflate " (since Linux 3.18)" |
| .\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_MEMORY_BALLOON . |
| .TP |
| .IR balloon_deflate " (since Linux 3.18)" |
| .\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS |
| .\" and |
| .\" .BR CONFIG_MEMORY_BALLOON . |
| .TP |
| .IR balloon_migrate " (since Linux 3.18)" |
| .\" commit 09316c09dde33aae14f34489d9e3d243ec0d5938 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_VM_EVENT_COUNTERS , |
| .\" .BR CONFIG_MEMORY_BALLOON , |
| .\" and |
| .\" .BR CONFIG_BALLOON_COMPACTION . |
| .TP |
| .IR nr_tlb_remote_flush " (since Linux 3.12)" |
| .\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_TLBFLUSH |
| .\" and |
| .\" .BR CONFIG_SMP . |
| .TP |
| .IR nr_tlb_remote_flush_received " (since Linux 3.12)" |
| .\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_TLBFLUSH |
| .\" and |
| .\" .BR CONFIG_SMP . |
| .TP |
| .IR nr_tlb_local_flush_all " (since Linux 3.12)" |
| .\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_TLBFLUSH . |
| .TP |
| .IR nr_tlb_local_flush_one " (since Linux 3.12)" |
| .\" commit 9824cf9753ecbe8f5b47aa9b2f218207defea211 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_TLBFLUSH . |
| .TP |
| .IR vmacache_find_calls " (since Linux 3.16)" |
| .\" commit 4f115147ff802267d0aa41e361c5aa5bd933d896 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_VM_VMACACHE . |
| .TP |
| .IR vmacache_find_hits " (since Linux 3.16)" |
| .\" commit 4f115147ff802267d0aa41e361c5aa5bd933d896 |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_VM_VMACACHE . |
| .TP |
| .IR vmacache_full_flushes " (since Linux 3.19)" |
| .\" commit f5f302e21257ebb0c074bbafc37606c26d28cc3d |
| .\" Present only if the kernel was configured with |
| .\" .BR CONFIG_DEBUG_VM_VMACACHE . |
| .RE |
| .TP |
| .IR /proc/zoneinfo " (since Linux 2.6.13)" |
| This file displays information about memory zones. |
| This is useful for analyzing virtual memory behavior. |
| .\" FIXME more should be said about /proc/zoneinfo |
| .SH NOTES |
| Many files contain strings (e.g., the environment and command line) |
| that are in the internal format, |
| with subfields terminated by null bytes (\(aq\e0\(aq). |
| When inspecting such files, you may find that the results are more readable |
| if you use a command of the following form to display them: |
| .PP |
| .in +4n |
| .EX |
| .RB "$" " cat \fIfile\fP | tr \(aq\e000\(aq \(aq\en\(aq" |
| .EE |
| .in |
| .PP |
| This manual page is incomplete, possibly inaccurate, and is the kind |
| of thing that needs to be updated very often. |
| .\" .SH ACKNOWLEDGEMENTS |
| .\" The material on /proc/sys/fs and /proc/sys/kernel is closely based on |
| .\" kernel source documentation files written by Rik van Riel. |
| .SH SEE ALSO |
| .BR cat (1), |
| .BR dmesg (1), |
| .BR find (1), |
| .BR free (1), |
| .BR htop (1), |
| .BR init (1), |
| .BR ps (1), |
| .BR pstree (1), |
| .BR tr (1), |
| .BR uptime (1), |
| .BR chroot (2), |
| .BR mmap (2), |
| .BR readlink (2), |
| .BR syslog (2), |
| .BR slabinfo (5), |
| .BR sysfs (5), |
| .BR hier (7), |
| .BR namespaces (7), |
| .BR time (7), |
| .BR arp (8), |
| .BR hdparm (8), |
| .BR ifconfig (8), |
| .BR lsmod (8), |
| .BR lspci (8), |
| .BR mount (8), |
| .BR netstat (8), |
| .BR procinfo (8), |
| .BR route (8), |
| .BR sysctl (8) |
| .PP |
| The Linux kernel source files: |
| .IR Documentation/filesystems/proc.txt , |
| .IR Documentation/sysctl/fs.txt , |
| .IR Documentation/sysctl/kernel.txt , |
| .IR Documentation/sysctl/net.txt , |
| and |
| .IR Documentation/sysctl/vm.txt . |