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fea681da | 1 | .\" Copyright (C) 1994, 1995 by Daniel Quinlan (quinlan@yggdrasil.com) |
f352b560 | 2 | .\" and Copyright (C) 2002-2008,2017 Michael Kerrisk <mtk.manpages@gmail.com> |
fea681da MK |
3 | .\" with networking additions from Alan Cox (A.Cox@swansea.ac.uk) |
4 | .\" and scsi additions from Michael Neuffer (neuffer@mail.uni-mainz.de) | |
5 | .\" and sysctl additions from Andries Brouwer (aeb@cwi.nl) | |
6 | .\" and System V IPC (as well as various other) additions from | |
c11b1abf | 7 | .\" Michael Kerrisk <mtk.manpages@gmail.com> |
fea681da | 8 | .\" |
e4a74ca8 | 9 | .\" SPDX-License-Identifier: GPL-2.0-or-later |
fea681da MK |
10 | .\" |
11 | .\" Modified 1995-05-17 by faith@cs.unc.edu | |
12 | .\" Minor changes by aeb and Marty Leisner (leisner@sdsp.mc.xerox.com). | |
13 | .\" Modified 1996-04-13, 1996-07-22 by aeb@cwi.nl | |
14 | .\" Modified 2001-12-16 by rwhron@earthlink.net | |
15 | .\" Modified 2002-07-13 by jbelton@shaw.ca | |
16 | .\" Modified 2002-07-22, 2003-05-27, 2004-04-06, 2004-05-25 | |
c11b1abf | 17 | .\" by Michael Kerrisk <mtk.manpages@gmail.com> |
5d6d14a0 MK |
18 | .\" 2004-11-17, mtk -- updated notes on /proc/loadavg |
19 | .\" 2004-12-01, mtk, rtsig-max and rtsig-nr went away in 2.6.8 | |
568105c6 MK |
20 | .\" 2004-12-14, mtk, updated 'statm', and fixed error in order of list |
21 | .\" 2005-05-12, mtk, updated 'stat' | |
6d64ca9c | 22 | .\" 2005-07-13, mtk, added /proc/sys/fs/mqueue/* |
363f747c MK |
23 | .\" 2005-09-16, mtk, Added /proc/sys/fs/suid_dumpable |
24 | .\" 2005-09-19, mtk, added /proc/zoneinfo | |
b4e9ee8f | 25 | .\" 2005-03-01, mtk, moved /proc/sys/fs/mqueue/* material to mq_overview.7. |
69119dc7 MK |
26 | .\" 2008-06-05, mtk, Added /proc/[pid]/oom_score, /proc/[pid]/oom_adj, |
27 | .\" /proc/[pid]/limits, /proc/[pid]/mountinfo, /proc/[pid]/mountstats, | |
28 | .\" and /proc/[pid]/fdinfo/*. | |
29 | .\" 2008-06-19, mtk, Documented /proc/[pid]/status. | |
cc2d5c36 | 30 | .\" 2008-07-15, mtk, added /proc/config.gz |
363f747c | 31 | .\" |
43d42cc0 | 32 | .\" FIXME cross check against Documentation/filesystems/proc.txt |
c13182ef | 33 | .\" to see what information could be imported from that file |
c533af9d | 34 | .\" into this file. |
fea681da | 35 | .\" |
6e00b7a8 | 36 | .TH PROC 5 2021-08-27 "Linux" "Linux Programmer's Manual" |
fea681da | 37 | .SH NAME |
9ee4a2b6 | 38 | proc \- process information pseudo-filesystem |
fea681da MK |
39 | .SH DESCRIPTION |
40 | The | |
31fa1fd2 | 41 | .B proc |
ac8727b6 | 42 | filesystem is a pseudo-filesystem which provides an interface to |
c13182ef MK |
43 | kernel data structures. |
44 | It is commonly mounted at | |
fea681da | 45 | .IR /proc . |
b574c52d MK |
46 | Typically, it is mounted automatically by the system, |
47 | but it can also be mounted manually using a command such as: | |
48 | .PP | |
49 | .in +4n | |
50 | .EX | |
51 | mount \-t proc proc /proc | |
52 | .EE | |
53 | .in | |
54 | .PP | |
7e174651 | 55 | Most of the files in the |
31fa1fd2 | 56 | .B proc |
7e174651 | 57 | filesystem are read-only, |
64165e01 | 58 | but some files are writable, allowing kernel variables to be changed. |
7e174651 | 59 | .\" |
fee59977 MK |
60 | .SS Mount options |
61 | The | |
31fa1fd2 | 62 | .B proc |
fee59977 MK |
63 | filesystem supports the following mount options: |
64 | .TP | |
65 | .BR hidepid "=\fIn\fP (since Linux 3.3)" | |
66 | .\" commit 0499680a42141d86417a8fbaa8c8db806bea1201 | |
67 | This option controls who can access the information in | |
68 | .IR /proc/[pid] | |
69 | directories. | |
70 | The argument, | |
71 | .IR n , | |
72 | is one of the following values: | |
73 | .RS | |
74 | .TP 4 | |
75 | 0 | |
76 | Everybody may access all | |
77 | .IR /proc/[pid] | |
78 | directories. | |
79 | This is the traditional behavior, | |
80 | and the default if this mount option is not specified. | |
81 | .TP | |
82 | 1 | |
83 | Users may not access files and subdirectories inside any | |
84 | .IR /proc/[pid] | |
85 | directories but their own (the | |
86 | .IR /proc/[pid] | |
87 | directories themselves remain visible). | |
88 | Sensitive files such as | |
97949440 | 89 | .IR /proc/[pid]/cmdline |
fee59977 | 90 | and |
97949440 | 91 | .IR /proc/[pid]/status |
fee59977 MK |
92 | are now protected against other users. |
93 | This makes it impossible to learn whether any user is running a | |
94 | specific program | |
95 | (so long as the program doesn't otherwise reveal itself by its behavior). | |
96 | .\" As an additional bonus, since | |
97949440 | 97 | .\" .IR /proc/[pid]/cmdline |
9d4976ce | 98 | .\" is inaccessible for other users, |
fee59977 MK |
99 | .\" poorly written programs passing sensitive information via |
100 | .\" program arguments are now protected against local eavesdroppers. | |
101 | .TP | |
102 | 2 | |
103 | As for mode 1, but in addition the | |
104 | .IR /proc/[pid] | |
105 | directories belonging to other users become invisible. | |
106 | This means that | |
107 | .IR /proc/[pid] | |
108 | entries can no longer be used to discover the PIDs on the system. | |
109 | This doesn't hide the fact that a process with a specific PID value exists | |
9bc87ed0 | 110 | (it can be learned by other means, for example, by "kill \-0 $PID"), |
fee59977 MK |
111 | but it hides a process's UID and GID, |
112 | which could otherwise be learned by employing | |
113 | .BR stat (2) | |
114 | on a | |
115 | .IR /proc/[pid] | |
116 | directory. | |
117 | This greatly complicates an attacker's task of gathering | |
118 | information about running processes (e.g., discovering whether | |
119 | some daemon is running with elevated privileges, | |
120 | whether another user is running some sensitive program, | |
121 | whether other users are running any program at all, and so on). | |
122 | .RE | |
123 | .TP | |
124 | .BR gid "=\fIgid\fP (since Linux 3.3)" | |
125 | .\" commit 0499680a42141d86417a8fbaa8c8db806bea1201 | |
126 | Specifies the ID of a group whose members are authorized to | |
127 | learn process information otherwise prohibited by | |
128 | .BR hidepid | |
95b1c1d1 | 129 | (i.e., users in this group behave as though |
fee59977 MK |
130 | .I /proc |
131 | was mounted with | |
95b1c1d1 | 132 | .IR hidepid=0 ). |
fee59977 MK |
133 | This group should be used instead of approaches such as putting |
134 | nonroot users into the | |
135 | .BR sudoers (5) | |
136 | file. | |
3c7cfa32 MK |
137 | .\" |
138 | .SS Overview | |
139 | Underneath | |
140 | .IR /proc , | |
141 | there are the following general groups of files and subdirectories: | |
142 | .TP | |
143 | .IR /proc/[pid] " subdirectories" | |
144 | Each one of these subdirectories contains files and subdirectories | |
145 | exposing information about the process with the corresponding process ID. | |
146 | .IP | |
147 | Underneath each of the | |
148 | .I /proc/[pid] | |
149 | directories, a | |
7fe3b32b | 150 | .I task |
3c7cfa32 | 151 | subdirectory contains subdirectories of the form |
7fe3b32b | 152 | .IR task/[tid] , |
3c7cfa32 MK |
153 | which contain corresponding information about each of the threads |
154 | in the process, where | |
155 | .I tid | |
156 | is the kernel thread ID of the thread. | |
01df7b70 MK |
157 | .IP |
158 | The | |
159 | .I /proc/[pid] | |
160 | subdirectories are visible when iterating through | |
161 | .I /proc | |
162 | with | |
163 | .BR getdents (2) | |
164 | (and thus are visible when one uses | |
165 | .BR ls (1) | |
166 | to view the contents of | |
167 | .IR /proc ). | |
168 | .TP | |
169 | .IR /proc/[tid] " subdirectories" | |
170 | Each one of these subdirectories contains files and subdirectories | |
171 | exposing information about the thread with the corresponding thread ID. | |
37cd58d2 MK |
172 | The contents of these directories are the same as the corresponding |
173 | .IR /proc/[pid]/task/[tid] | |
174 | directories. | |
01df7b70 MK |
175 | .IP |
176 | The | |
177 | .I /proc/[tid] | |
178 | subdirectories are | |
179 | .I not | |
180 | visible when iterating through | |
181 | .I /proc | |
182 | with | |
183 | .BR getdents (2) | |
184 | (and thus are | |
185 | .I not | |
186 | visible when one uses | |
187 | .BR ls (1) | |
3c7cfa32 MK |
188 | to view the contents of |
189 | .IR /proc ). | |
190 | .TP | |
191 | .I /proc/self | |
192 | When a process accesses this magic symbolic link, | |
193 | it resolves to the process's own | |
194 | .I /proc/[pid] | |
195 | directory. | |
196 | .TP | |
184d797d | 197 | .I /proc/thread\-self |
3c7cfa32 MK |
198 | When a thread accesses this magic symbolic link, |
199 | it resolves to the process's own | |
7fe3b32b | 200 | .I /proc/self/task/[tid] |
3c7cfa32 MK |
201 | directory. |
202 | .TP | |
184d797d | 203 | .I /proc/[a\-z]* |
3c7cfa32 MK |
204 | Various other files and subdirectories under |
205 | .I /proc | |
206 | expose system-wide information. | |
207 | .PP | |
208 | All of the above are described in more detail below. | |
209 | .\" | |
fee59977 | 210 | .SS Files and directories |
71b36dc7 MK |
211 | The following list provides details of many of the files and directories |
212 | under the | |
743638fd MK |
213 | .I /proc |
214 | hierarchy. | |
fea681da | 215 | .TP |
69119dc7 | 216 | .I /proc/[pid] |
fea681da MK |
217 | There is a numerical subdirectory for each running process; the |
218 | subdirectory is named by the process ID. | |
1e6a8e2f MK |
219 | Each |
220 | .I /proc/[pid] | |
e96ad1fd MK |
221 | subdirectory contains the pseudo-files and directories described below. |
222 | .IP | |
223 | The files inside each | |
224 | .I /proc/[pid] | |
225 | directory are normally owned by the effective user and | |
3bdb8ec5 MK |
226 | effective group ID of the process. |
227 | However, as a security measure, the ownership is made | |
228 | .IR root:root | |
229 | if the process's "dumpable" attribute is set to a value other than 1. | |
fb49322d | 230 | .IP |
ae636827 MK |
231 | Before Linux 4.11, |
232 | .\" commit 68eb94f16227336a5773b83ecfa8290f1d6b78ce | |
233 | .IR root:root | |
234 | meant the "global" root user ID and group ID | |
235 | (i.e., UID 0 and GID 0 in the initial user namespace). | |
236 | Since Linux 4.11, | |
237 | if the process is in a noninitial user namespace that has a | |
238 | valid mapping for user (group) ID 0 inside the namespace, then | |
239 | the user (group) ownership of the files under | |
240 | .I /proc/[pid] | |
241 | is instead made the same as the root user (group) ID of the namespace. | |
242 | This means that inside a container, | |
243 | things work as expected for the container "root" user. | |
244 | .IP | |
fb49322d | 245 | The process's "dumpable" attribute may change for the following reasons: |
3bdb8ec5 MK |
246 | .RS |
247 | .IP * 3 | |
248 | The attribute was explicitly set via the | |
249 | .BR prctl (2) | |
250 | .B PR_SET_DUMPABLE | |
251 | operation. | |
252 | .IP * | |
253 | The attribute was reset to the value in the file | |
254 | .IR /proc/sys/fs/suid_dumpable | |
255 | (described below), for the reasons described in | |
256 | .BR prctl (2). | |
257 | .RE | |
258 | .IP | |
259 | Resetting the "dumpable" attribute to 1 reverts the ownership of the | |
260 | .IR /proc/[pid]/* | |
eada5570 | 261 | files to the process's effective UID and GID. |
03687209 MK |
262 | Note, however, that if the effective UID or GID is subsequently modified, |
263 | then the "dumpable" attribute may be reset, as described in | |
264 | .BR prctl (2). | |
265 | Therefore, it may be desirable to reset the "dumpable" attribute | |
266 | .I after | |
267 | making any desired changes to the process's effective UID or GID. | |
b7a42567 MK |
268 | .TP |
269 | .I /proc/[pid]/attr | |
270 | .\" https://lwn.net/Articles/28222/ | |
271 | .\" From: Stephen Smalley <sds@epoch.ncsc.mil> | |
272 | .\" To: LKML and others | |
273 | .\" Subject: [RFC][PATCH] Process Attribute API for Security Modules | |
274 | .\" Date: 08 Apr 2003 16:17:52 -0400 | |
275 | .\" | |
b3fb99e8 MK |
276 | .\" http://www.nsa.gov/research/_files/selinux/papers/module/x362.shtml |
277 | .\" | |
b7a42567 MK |
278 | The files in this directory provide an API for security modules. |
279 | The contents of this directory are files that can be read and written | |
280 | in order to set security-related attributes. | |
281 | This directory was added to support SELinux, | |
282 | but the intention was that the API be general enough to support | |
283 | other security modules. | |
284 | For the purpose of explanation, | |
285 | examples of how SELinux uses these files are provided below. | |
2dad4c59 | 286 | .IP |
b7a42567 MK |
287 | This directory is present only if the kernel was configured with |
288 | .BR CONFIG_SECURITY . | |
289 | .TP | |
290 | .IR /proc/[pid]/attr/current " (since Linux 2.6.0)" | |
291 | The contents of this file represent the current | |
292 | security attributes of the process. | |
2dad4c59 | 293 | .IP |
fd44bdc7 TY |
294 | In SELinux, this file is used to get the security context of a process. |
295 | Prior to Linux 2.6.11, this file could not be used to set the security | |
296 | context (a write was always denied), since SELinux limited process security | |
297 | transitions to | |
b7a42567 MK |
298 | .BR execve (2) |
299 | (see the description of | |
300 | .IR /proc/[pid]/attr/exec , | |
301 | below). | |
fd44bdc7 TY |
302 | Since Linux 2.6.11, SELinux lifted this restriction and began supporting |
303 | "set" operations via writes to this node if authorized by policy, | |
304 | although use of this operation is only suitable for applications that are | |
305 | trusted to maintain any desired separation between the old and new security | |
b6620a25 | 306 | contexts. |
8adf5862 | 307 | .IP |
b6620a25 | 308 | Prior to Linux 2.6.28, SELinux did not allow threads within a |
83a20af0 | 309 | multithreaded process to set their security context via this node |
fd44bdc7 | 310 | as it would yield an inconsistency among the security contexts of the |
b6620a25 MK |
311 | threads sharing the same memory space. |
312 | Since Linux 2.6.28, SELinux lifted | |
fd44bdc7 | 313 | this restriction and began supporting "set" operations for threads within |
b6620a25 | 314 | a multithreaded process if the new security context is bounded by the old |
fd44bdc7 TY |
315 | security context, where the bounded relation is defined in policy and |
316 | guarantees that the new security context has a subset of the permissions | |
317 | of the old security context. | |
8adf5862 | 318 | .IP |
b7a42567 MK |
319 | Other security modules may choose to support "set" operations via |
320 | writes to this node. | |
321 | .TP | |
322 | .IR /proc/[pid]/attr/exec " (since Linux 2.6.0)" | |
323 | This file represents the attributes to assign to the | |
324 | process upon a subsequent | |
325 | .BR execve (2). | |
2dad4c59 | 326 | .IP |
b7a42567 MK |
327 | In SELinux, |
328 | this is needed to support role/domain transitions, and | |
329 | .BR execve (2) | |
330 | is the preferred point to make such transitions because it offers better | |
331 | control over the initialization of the process in the new security label | |
332 | and the inheritance of state. | |
333 | In SELinux, this attribute is reset on | |
334 | .BR execve (2) | |
335 | so that the new program reverts to the default behavior for any | |
336 | .BR execve (2) | |
337 | calls that it may make. | |
338 | In SELinux, a process can set | |
339 | only its own | |
340 | .I /proc/[pid]/attr/exec | |
341 | attribute. | |
342 | .TP | |
343 | .IR /proc/[pid]/attr/fscreate " (since Linux 2.6.0)" | |
344 | This file represents the attributes to assign to files | |
345 | created by subsequent calls to | |
346 | .BR open (2), | |
347 | .BR mkdir (2), | |
348 | .BR symlink (2), | |
349 | and | |
350 | .BR mknod (2) | |
2dad4c59 | 351 | .IP |
b7a42567 MK |
352 | SELinux employs this file to support creation of a file |
353 | (using the aforementioned system calls) | |
354 | in a secure state, | |
355 | so that there is no risk of inappropriate access being obtained | |
356 | between the time of creation and the time that attributes are set. | |
357 | In SELinux, this attribute is reset on | |
358 | .BR execve (2), | |
359 | so that the new program reverts to the default behavior for | |
360 | any file creation calls it may make, but the attribute will persist | |
361 | across multiple file creation calls within a program unless it is | |
362 | explicitly reset. | |
363 | In SELinux, a process can set only its own | |
364 | .IR /proc/[pid]/attr/fscreate | |
365 | attribute. | |
366 | .TP | |
666db07e MK |
367 | .IR /proc/[pid]/attr/keycreate " (since Linux 2.6.18)" |
368 | .\" commit 4eb582cf1fbd7b9e5f466e3718a59c957e75254e | |
666db07e MK |
369 | If a process writes a security context into this file, |
370 | all subsequently created keys | |
371 | .RB ( add_key (2)) | |
372 | will be labeled with this context. | |
373 | For further information, see the kernel source file | |
6b3ead8f ES |
374 | .I Documentation/security/keys/core.rst |
375 | (or file | |
376 | .\" commit b68101a1e8f0263dbc7b8375d2a7c57c6216fb76 | |
377 | .I Documentation/security/keys.txt | |
378 | on Linux between 3.0 and 4.13, or | |
379 | .\" commit d410fa4ef99112386de5f218dd7df7b4fca910b4 | |
380 | .I Documentation/keys.txt | |
381 | before Linux 3.0). | |
2702dc21 | 382 | .TP |
93401860 MK |
383 | .IR /proc/[pid]/attr/prev " (since Linux 2.6.0)" |
384 | This file contains the security context of the process before the last | |
385 | .BR execve (2); | |
386 | that is, the previous value of | |
387 | .IR /proc/[pid]/attr/current . | |
388 | .TP | |
2702dc21 MK |
389 | .IR /proc/[pid]/attr/socketcreate " (since Linux 2.6.18)" |
390 | .\" commit 42c3e03ef6b298813557cdb997bd6db619cd65a2 | |
391 | If a process writes a security context into this file, | |
392 | all subsequently created sockets will be labeled with this context. | |
39b35179 MK |
393 | .TP |
394 | .IR /proc/[pid]/autogroup " (since Linux 2.6.38)" | |
395 | .\" commit 5091faa449ee0b7d73bc296a93bca9540fc51d0a | |
396 | See | |
397 | .BR sched (7). | |
fea681da | 398 | .TP |
d6bec36e MK |
399 | .IR /proc/[pid]/auxv " (since 2.6.0)" |
400 | .\" Precisely: Linux 2.6.0-test7 | |
857f1942 | 401 | This contains the contents of the ELF interpreter information passed |
c13182ef | 402 | to the process at exec time. |
857f1942 | 403 | The format is one \fIunsigned long\fP ID |
c13182ef | 404 | plus one \fIunsigned long\fP value for each entry. |
857f1942 | 405 | The last entry contains two zeros. |
4c69c692 MK |
406 | See also |
407 | .BR getauxval (3). | |
2dad4c59 | 408 | .IP |
82664739 MK |
409 | Permission to access this file is governed by a ptrace access mode |
410 | .B PTRACE_MODE_READ_FSCREDS | |
411 | check; see | |
412 | .BR ptrace (2). | |
b5d204d0 | 413 | .TP |
8d708d6b | 414 | .IR /proc/[pid]/cgroup " (since Linux 2.6.24)" |
5c2181ad MK |
415 | See |
416 | .BR cgroups (7). | |
76e0451c MK |
417 | .TP |
418 | .IR /proc/[pid]/clear_refs " (since Linux 2.6.22)" | |
419 | .\" commit b813e931b4c8235bb42e301096ea97dbdee3e8fe (2.6.22) | |
420 | .\" commit 398499d5f3613c47f2143b8c54a04efb5d7a6da9 (2.6.32) | |
421 | .\" commit 040fa02077de01c7e08fa75be6125e4ca5636011 (3.11) | |
b4e9ee8f | 422 | .\" |
b4e9ee8f | 423 | .\" "Clears page referenced bits shown in smaps output" |
76e0451c | 424 | .\" write-only, writable only by the owner of the process |
2dad4c59 | 425 | .IP |
76e0451c | 426 | This is a write-only file, writable only by owner of the process. |
2dad4c59 | 427 | .IP |
76e0451c MK |
428 | The following values may be written to the file: |
429 | .RS | |
430 | .TP | |
431 | 1 (since Linux 2.6.22) | |
432 | .\" Internally: CLEAR_REFS_ALL | |
433 | Reset the PG_Referenced and ACCESSED/YOUNG | |
434 | bits for all the pages associated with the process. | |
435 | (Before kernel 2.6.32, writing any nonzero value to this file | |
436 | had this effect.) | |
437 | .TP | |
438 | 2 (since Linux 2.6.32) | |
439 | .\" Internally: CLEAR_REFS_ANON | |
440 | Reset the PG_Referenced and ACCESSED/YOUNG | |
441 | bits for all anonymous pages associated with the process. | |
442 | .TP | |
443 | 3 (since Linux 2.6.32) | |
444 | .\" Internally: CLEAR_REFS_MAPPED | |
445 | Reset the PG_Referenced and ACCESSED/YOUNG | |
446 | bits for all file-mapped pages associated with the process. | |
447 | .RE | |
448 | .IP | |
449 | Clearing the PG_Referenced and ACCESSED/YOUNG bits provides a method | |
450 | to measure approximately how much memory a process is using. | |
322d49fb | 451 | One first inspects the values in the "Referenced" fields |
76e0451c MK |
452 | for the VMAs shown in |
453 | .IR /proc/[pid]/smaps | |
454 | to get an idea of the memory footprint of the | |
455 | process. | |
456 | One then clears the PG_Referenced and ACCESSED/YOUNG bits | |
457 | and, after some measured time interval, | |
322d49fb | 458 | once again inspects the values in the "Referenced" fields |
76e0451c MK |
459 | to get an idea of the change in memory footprint of the |
460 | process during the measured interval. | |
461 | If one is interested only in inspecting the selected mapping types, | |
462 | then the value 2 or 3 can be used instead of 1. | |
2dad4c59 | 463 | .IP |
dfdf642e | 464 | Further values can be written to affect different properties: |
76e0451c MK |
465 | .RS |
466 | .TP | |
467 | 4 (since Linux 3.11) | |
468 | Clear the soft-dirty bit for all the pages associated with the process. | |
469 | .\" Internally: CLEAR_REFS_SOFT_DIRTY | |
470 | This is used (in conjunction with | |
471 | .IR /proc/[pid]/pagemap ) | |
472 | by the check-point restore system to discover which pages of a process | |
473 | have been dirtied since the file | |
474 | .IR /proc/[pid]/clear_refs | |
475 | was written to. | |
dfdf642e NK |
476 | .TP |
477 | 5 (since Linux 4.0) | |
478 | .\" Internally: CLEAR_REFS_MM_HIWATER_RSS | |
0989246e MK |
479 | Reset the peak resident set size ("high water mark") to the process's |
480 | current resident set size value. | |
76e0451c MK |
481 | .RE |
482 | .IP | |
483 | Writing any value to | |
484 | .IR /proc/[pid]/clear_refs | |
485 | other than those listed above has no effect. | |
2dad4c59 | 486 | .IP |
76e0451c MK |
487 | The |
488 | .IR /proc/[pid]/clear_refs | |
489 | file is present only if the | |
490 | .B CONFIG_PROC_PAGE_MONITOR | |
491 | kernel configuration option is enabled. | |
857f1942 | 492 | .TP |
69119dc7 | 493 | .I /proc/[pid]/cmdline |
6975c16e | 494 | This read-only file holds the complete command line for the process, |
b447cd58 MK |
495 | unless the process is a zombie. |
496 | .\" In 2.3.26, this also used to be true if the process was swapped out. | |
497 | In the latter case, there is nothing in this file: | |
75b94dc3 | 498 | that is, a read on this file will return 0 characters. |
b447cd58 | 499 | The command-line arguments appear in this file as a set of |
d1a71985 | 500 | strings separated by null bytes (\(aq\e0\(aq), |
6596d270 | 501 | with a further null byte after the last string. |
ee669cca MF |
502 | .IP |
503 | If, after an | |
504 | .BR execve (2), | |
b258106f MK |
505 | the process modifies its |
506 | .I argv | |
507 | strings, those changes will show up here. | |
508 | This is not the same thing as modifying the | |
509 | .I argv | |
510 | array. | |
ee669cca MF |
511 | .IP |
512 | Furthermore, a process may change the memory location that this file refers via | |
513 | .BR prctl (2) | |
514 | operations such as | |
515 | .BR PR_SET_MM_ARG_START . | |
4ad5b7a5 JW |
516 | .IP |
517 | Think of this file as the command line that the process wants you to see. | |
32d7ef00 MK |
518 | .TP |
519 | .IR /proc/[pid]/comm " (since Linux 2.6.33)" | |
520 | .\" commit 4614a696bd1c3a9af3a08f0e5874830a85b889d4 | |
521 | This file exposes the process's | |
522 | .I comm | |
523 | value\(emthat is, the command name associated with the process. | |
524 | Different threads in the same process may have different | |
525 | .I comm | |
526 | values, accessible via | |
527 | .IR /proc/[pid]/task/[tid]/comm . | |
528 | A thread may modify its | |
529 | .I comm | |
530 | value, or that of any of other thread in the same thread group (see | |
531 | the discussion of | |
532 | .B CLONE_THREAD | |
533 | in | |
534 | .BR clone (2)), | |
535 | by writing to the file | |
536 | .IR /proc/self/task/[tid]/comm . | |
537 | Strings longer than | |
538 | .B TASK_COMM_LEN | |
b463b03f | 539 | (16) characters (including the terminating null byte) are silently truncated. |
2dad4c59 | 540 | .IP |
ef4f4031 | 541 | This file provides a superset of the |
32d7ef00 MK |
542 | .BR prctl (2) |
543 | .B PR_SET_NAME | |
544 | and | |
545 | .B PR_GET_NAME | |
546 | operations, and is employed by | |
547 | .BR pthread_setname_np (3) | |
548 | when used to rename threads other than the caller. | |
b65e24c3 MK |
549 | The value in this file is used for the |
550 | .I %e | |
551 | specifier in | |
552 | .IR /proc/sys/kernel/core_pattern ; | |
553 | see | |
a00214da | 554 | .BR core (5). |
fea681da | 555 | .TP |
7e07d950 | 556 | .IR /proc/[pid]/coredump_filter " (since Linux 2.6.23)" |
b4e9ee8f MK |
557 | See |
558 | .BR core (5). | |
5c411b17 | 559 | .TP |
7e07d950 MK |
560 | .IR /proc/[pid]/cpuset " (since Linux 2.6.12)" |
561 | .\" and/proc/[pid]/task/[tid]/cpuset | |
5c411b17 MK |
562 | See |
563 | .BR cpuset (7). | |
b4e9ee8f | 564 | .TP |
69119dc7 | 565 | .I /proc/[pid]/cwd |
c13182ef | 566 | This is a symbolic link to the current working directory of the process. |
59a40ed7 MK |
567 | To find out the current working directory of process 20, |
568 | for instance, you can do this: | |
2dad4c59 | 569 | .IP |
59a40ed7 | 570 | .in +4n |
37d5e699 | 571 | .EX |
9eff2f49 | 572 | .RB "$" " cd /proc/20/cwd; pwd \-P" |
37d5e699 | 573 | .EE |
59a40ed7 | 574 | .in |
2dad4c59 | 575 | .IP |
afcaf646 | 576 | .\" The following was still true as at kernel 2.6.13 |
c13182ef MK |
577 | In a multithreaded process, the contents of this symbolic link |
578 | are not available if the main thread has already terminated | |
afcaf646 | 579 | (typically by calling |
59a40ed7 | 580 | .BR pthread_exit (3)). |
2dad4c59 | 581 | .IP |
b902fe18 MK |
582 | Permission to dereference or read |
583 | .RB ( readlink (2)) | |
584 | this symbolic link is governed by a ptrace access mode | |
585 | .B PTRACE_MODE_READ_FSCREDS | |
586 | check; see | |
587 | .BR ptrace (2). | |
fea681da | 588 | .TP |
69119dc7 | 589 | .I /proc/[pid]/environ |
09651080 MK |
590 | This file contains the initial environment that was set |
591 | when the currently executing program was started via | |
592 | .BR execve (2). | |
d1a71985 | 593 | The entries are separated by null bytes (\(aq\e0\(aq), |
b4e9ee8f | 594 | and there may be a null byte at the end. |
fea681da | 595 | Thus, to print out the environment of process 1, you would do: |
37d5e699 | 596 | .IP |
a08ea57c | 597 | .in +4n |
37d5e699 | 598 | .EX |
d1081b23 | 599 | .RB "$" " cat /proc/1/environ | tr \(aq\e000\(aq \(aq\en\(aq" |
37d5e699 | 600 | .EE |
a08ea57c | 601 | .in |
2dad4c59 | 602 | .IP |
09651080 MK |
603 | If, after an |
604 | .BR execve (2), | |
605 | the process modifies its environment | |
c187d2a1 | 606 | (e.g., by calling functions such as |
387e2438 MF |
607 | .BR putenv (3) |
608 | or modifying the | |
609 | .BR environ (7) | |
610 | variable directly), | |
09651080 MK |
611 | this file will |
612 | .I not | |
613 | reflect those changes. | |
2dad4c59 | 614 | .IP |
c187d2a1 | 615 | Furthermore, a process may change the memory location that this file refers via |
387e2438 | 616 | .BR prctl (2) |
c187d2a1 | 617 | operations such as |
387e2438 | 618 | .BR PR_SET_MM_ENV_START . |
2dad4c59 | 619 | .IP |
82664739 MK |
620 | Permission to access this file is governed by a ptrace access mode |
621 | .B PTRACE_MODE_READ_FSCREDS | |
622 | check; see | |
623 | .BR ptrace (2). | |
fea681da | 624 | .TP |
69119dc7 | 625 | .I /proc/[pid]/exe |
fea681da | 626 | Under Linux 2.2 and later, this file is a symbolic link |
2d7195b8 | 627 | containing the actual pathname of the executed command. |
c13182ef MK |
628 | This symbolic link can be dereferenced normally; attempting to open |
629 | it will open the executable. | |
630 | You can even type | |
69119dc7 | 631 | .I /proc/[pid]/exe |
06dd061c | 632 | to run another copy of the same executable that is being run by |
69119dc7 | 633 | process [pid]. |
7e3c767a GJ |
634 | If the pathname has been unlinked, the symbolic link will contain the |
635 | string \(aq(deleted)\(aq appended to the original pathname. | |
afcaf646 | 636 | .\" The following was still true as at kernel 2.6.13 |
c13182ef MK |
637 | In a multithreaded process, the contents of this symbolic link |
638 | are not available if the main thread has already terminated | |
afcaf646 MK |
639 | (typically by calling |
640 | .BR pthread_exit (3)). | |
2dad4c59 | 641 | .IP |
b902fe18 MK |
642 | Permission to dereference or read |
643 | .RB ( readlink (2)) | |
644 | this symbolic link is governed by a ptrace access mode | |
645 | .B PTRACE_MODE_READ_FSCREDS | |
646 | check; see | |
647 | .BR ptrace (2). | |
2dad4c59 | 648 | .IP |
eb9a0b2f | 649 | Under Linux 2.0 and earlier, |
69119dc7 | 650 | .I /proc/[pid]/exe |
c13182ef MK |
651 | is a pointer to the binary which was executed, |
652 | and appears as a symbolic link. | |
653 | A | |
fea681da MK |
654 | .BR readlink (2) |
655 | call on this file under Linux 2.0 returns a string in the format: | |
2dad4c59 | 656 | .IP |
59a40ed7 | 657 | [device]:inode |
2dad4c59 | 658 | .IP |
fea681da MK |
659 | For example, [0301]:1502 would be inode 1502 on device major 03 (IDE, |
660 | MFM, etc. drives) minor 01 (first partition on the first drive). | |
2dad4c59 | 661 | .IP |
fea681da | 662 | .BR find (1) |
59a40ed7 MK |
663 | with the |
664 | .I \-inum | |
665 | option can be used to locate the file. | |
fea681da | 666 | .TP |
d4529654 | 667 | .I /proc/[pid]/fd/ |
fea681da MK |
668 | This is a subdirectory containing one entry for each file which the |
669 | process has open, named by its file descriptor, and which is a | |
c13182ef | 670 | symbolic link to the actual file. |
f78ed33a | 671 | Thus, 0 is standard input, 1 standard output, 2 standard error, and so on. |
2dad4c59 | 672 | .IP |
f75715e0 MK |
673 | For file descriptors for pipes and sockets, |
674 | the entries will be symbolic links whose content is the | |
675 | file type with the inode. | |
d4529654 MF |
676 | A |
677 | .BR readlink (2) | |
678 | call on this file returns a string in the format: | |
2dad4c59 | 679 | .IP |
d4529654 | 680 | type:[inode] |
2dad4c59 | 681 | .IP |
f75715e0 MK |
682 | For example, |
683 | .I socket:[2248868] | |
684 | will be a socket and its inode is 2248868. | |
685 | For sockets, that inode can be used to find more information | |
686 | in one of the files under | |
d4529654 | 687 | .IR /proc/net/ . |
2dad4c59 | 688 | .IP |
2b7a2ac5 MK |
689 | For file descriptors that have no corresponding inode |
690 | (e.g., file descriptors produced by | |
89e284a2 | 691 | .BR bpf (2), |
2b7a2ac5 MK |
692 | .BR epoll_create (2), |
693 | .BR eventfd (2), | |
694 | .BR inotify_init (2), | |
89e284a2 | 695 | .BR perf_event_open (2), |
2b7a2ac5 | 696 | .BR signalfd (2), |
89e284a2 | 697 | .BR timerfd_create (2), |
2b7a2ac5 | 698 | and |
e8675558 | 699 | .BR userfaultfd (2)), |
2b7a2ac5 | 700 | the entry will be a symbolic link with contents of the form |
2dad4c59 | 701 | .IP |
2b7a2ac5 | 702 | anon_inode:<file-type> |
2dad4c59 | 703 | .IP |
e2a5929d | 704 | In many cases (but not all), the |
2b7a2ac5 MK |
705 | .I file-type |
706 | is surrounded by square brackets. | |
2dad4c59 | 707 | .IP |
2b7a2ac5 MK |
708 | For example, an epoll file descriptor will have a symbolic link |
709 | whose content is the string | |
710 | .IR "anon_inode:[eventpoll]" . | |
2dad4c59 | 711 | .IP |
d4529654 | 712 | .\"The following was still true as at kernel 2.6.13 |
afcaf646 | 713 | In a multithreaded process, the contents of this directory |
c13182ef | 714 | are not available if the main thread has already terminated |
afcaf646 MK |
715 | (typically by calling |
716 | .BR pthread_exit (3)). | |
2dad4c59 | 717 | .IP |
20c1a631 MK |
718 | Programs that take a filename as a command-line argument, |
719 | but don't take input from standard input if no argument is supplied, | |
720 | and programs that write to a file named as a command-line argument, | |
721 | but don't send their output to standard output | |
59a40ed7 | 722 | if no argument is supplied, can nevertheless be made to use |
20c1a631 MK |
723 | standard input or standard output by using |
724 | .IR /proc/[pid]/fd | |
725 | files as command-line arguments. | |
59a40ed7 MK |
726 | For example, assuming that |
727 | .I \-i | |
728 | is the flag designating an input file and | |
729 | .I \-o | |
730 | is the flag designating an output file: | |
37d5e699 | 731 | .IP |
a08ea57c | 732 | .in +4n |
37d5e699 | 733 | .EX |
b43a3b30 | 734 | .RB "$" " foobar \-i /proc/self/fd/0 \-o /proc/self/fd/1 ..." |
37d5e699 | 735 | .EE |
a08ea57c | 736 | .in |
2dad4c59 | 737 | .IP |
fea681da MK |
738 | and you have a working filter. |
739 | .\" The following is not true in my tests (MTK): | |
740 | .\" Note that this will not work for | |
741 | .\" programs that seek on their files, as the files in the fd directory | |
742 | .\" are not seekable. | |
2dad4c59 | 743 | .IP |
59a40ed7 MK |
744 | .I /proc/self/fd/N |
745 | is approximately the same as | |
746 | .I /dev/fd/N | |
008f1ecc | 747 | in some UNIX and UNIX-like systems. |
c13182ef | 748 | Most Linux MAKEDEV scripts symbolically link |
59a40ed7 MK |
749 | .I /dev/fd |
750 | to | |
751 | .IR /proc/self/fd , | |
752 | in fact. | |
2dad4c59 | 753 | .IP |
59a40ed7 MK |
754 | Most systems provide symbolic links |
755 | .IR /dev/stdin , | |
756 | .IR /dev/stdout , | |
757 | and | |
758 | .IR /dev/stderr , | |
759 | which respectively link to the files | |
760 | .IR 0 , | |
761 | .IR 1 , | |
762 | and | |
763 | .IR 2 | |
764 | in | |
765 | .IR /proc/self/fd . | |
766 | Thus the example command above could be written as: | |
d6bd89f3 | 767 | .IP |
59a40ed7 | 768 | .in +4n |
37d5e699 | 769 | .EX |
b43a3b30 | 770 | .RB "$" " foobar \-i /dev/stdin \-o /dev/stdout ..." |
37d5e699 | 771 | .EE |
59a40ed7 | 772 | .in |
138a191e MK |
773 | .IP |
774 | Permission to dereference or read | |
775 | .RB ( readlink (2)) | |
776 | the symbolic links in this directory is governed by a ptrace access mode | |
777 | .B PTRACE_MODE_READ_FSCREDS | |
778 | check; see | |
779 | .BR ptrace (2). | |
81c8aeb6 LW |
780 | .IP |
781 | Note that for file descriptors referring to inodes (pipes and sockets, see above), | |
782 | those inodes still have permission bits and ownership information | |
783 | distinct from those of the | |
784 | .I /proc/[pid]/fd | |
785 | entry, | |
786 | and that the owner may differ from the user and group IDs of the process. | |
787 | An unprivileged process may lack permissions to open them, as in this example: | |
788 | .IP | |
789 | .in +4n | |
790 | .EX | |
184d797d | 791 | .RB "$" " echo test | sudo \-u nobody cat" |
81c8aeb6 | 792 | test |
184d797d | 793 | .RB "$" " echo test | sudo \-u nobody cat /proc/self/fd/0" |
81c8aeb6 LW |
794 | cat: /proc/self/fd/0: Permission denied |
795 | .EE | |
796 | .in | |
797 | .IP | |
798 | File descriptor 0 refers to the pipe created by the shell | |
799 | and owned by that shell's user, which is not | |
800 | .IR nobody , | |
801 | so | |
802 | .B cat | |
803 | does not have permission to create a new file descriptor to read from that inode, | |
804 | even though it can still read from its existing file descriptor 0. | |
69ab425e | 805 | .TP |
7e07d950 | 806 | .IR /proc/[pid]/fdinfo/ " (since Linux 2.6.22)" |
69ab425e MK |
807 | This is a subdirectory containing one entry for each file which the |
808 | process has open, named by its file descriptor. | |
0275956d | 809 | The files in this directory are readable only by the owner of the process. |
69ab425e | 810 | The contents of each file can be read to obtain information |
0275956d MK |
811 | about the corresponding file descriptor. |
812 | The content depends on the type of file referred to by the | |
d9cb0d7d | 813 | corresponding file descriptor. |
2dad4c59 | 814 | .IP |
0275956d | 815 | For regular files and directories, we see something like: |
37d5e699 | 816 | .IP |
69ab425e | 817 | .in +4n |
37d5e699 | 818 | .EX |
69ab425e MK |
819 | .RB "$" " cat /proc/12015/fdinfo/4" |
820 | pos: 1000 | |
821 | flags: 01002002 | |
0275956d | 822 | mnt_id: 21 |
37d5e699 | 823 | .EE |
69ab425e | 824 | .in |
2dad4c59 | 825 | .IP |
9599cbb3 MK |
826 | The fields are as follows: |
827 | .RS | |
828 | .TP | |
69ab425e | 829 | .I pos |
9599cbb3 MK |
830 | This is a decimal number showing the file offset. |
831 | .TP | |
69ab425e | 832 | .I flags |
9599cbb3 | 833 | This is an octal number that displays the |
69ab425e MK |
834 | file access mode and file status flags (see |
835 | .BR open (2)). | |
d7e537ce MK |
836 | If the close-on-exec file descriptor flag is set, then |
837 | .I flags | |
838 | will also include the value | |
839 | .BR O_CLOEXEC . | |
2dad4c59 | 840 | .IP |
d7e537ce MK |
841 | Before Linux 3.1, |
842 | .\" commit 1117f72ea0217ba0cc19f05adbbd8b9a397f5ab7 | |
843 | this field incorrectly displayed the setting of | |
844 | .B O_CLOEXEC | |
845 | at the time the file was opened, | |
846 | rather than the current setting of the close-on-exec flag. | |
9599cbb3 MK |
847 | .TP |
848 | .I | |
0275956d | 849 | .I mnt_id |
9599cbb3 | 850 | This field, present since Linux 3.15, |
0275956d | 851 | .\" commit 49d063cb353265c3af701bab215ac438ca7df36d |
525a8b54 | 852 | is the ID of the mount containing this file. |
0275956d MK |
853 | See the description of |
854 | .IR /proc/[pid]/mountinfo . | |
9599cbb3 MK |
855 | .RE |
856 | .IP | |
6e7622ee MK |
857 | For eventfd file descriptors (see |
858 | .BR eventfd (2)), | |
b6a7fd50 MK |
859 | we see (since Linux 3.8) |
860 | .\" commit cbac5542d48127b546a23d816380a7926eee1c25 | |
861 | the following fields: | |
2dad4c59 | 862 | .IP |
6e7622ee | 863 | .in +4n |
37d5e699 | 864 | .EX |
6e7622ee MK |
865 | pos: 0 |
866 | flags: 02 | |
867 | mnt_id: 10 | |
184d797d | 868 | eventfd\-count: 40 |
37d5e699 | 869 | .EE |
6e7622ee | 870 | .in |
2dad4c59 | 871 | .IP |
184d797d | 872 | .I eventfd\-count |
6e7622ee | 873 | is the current value of the eventfd counter, in hexadecimal. |
2dad4c59 | 874 | .IP |
58d375dd MK |
875 | For epoll file descriptors (see |
876 | .BR epoll (7)), | |
b6a7fd50 MK |
877 | we see (since Linux 3.8) |
878 | .\" commit 138d22b58696c506799f8de759804083ff9effae | |
879 | the following fields: | |
2dad4c59 | 880 | .IP |
58d375dd | 881 | .in +4n |
37d5e699 | 882 | .EX |
58d375dd MK |
883 | pos: 0 |
884 | flags: 02 | |
885 | mnt_id: 10 | |
886 | tfd: 9 events: 19 data: 74253d2500000009 | |
887 | tfd: 7 events: 19 data: 74253d2500000007 | |
37d5e699 | 888 | .EE |
58d375dd | 889 | .in |
2dad4c59 | 890 | .IP |
58d375dd MK |
891 | Each of the lines beginning |
892 | .I tfd | |
893 | describes one of the file descriptors being monitored via | |
894 | the epoll file descriptor (see | |
895 | .BR epoll_ctl (2) | |
896 | for some details). | |
897 | The | |
898 | .IR tfd | |
899 | field is the number of the file descriptor. | |
900 | The | |
901 | .I events | |
902 | field is a hexadecimal mask of the events being monitored for this file | |
903 | descriptor. | |
904 | The | |
905 | .I data | |
906 | field is the data value associated with this file descriptor. | |
2dad4c59 | 907 | .IP |
f8a14cac MK |
908 | For signalfd file descriptors (see |
909 | .BR signalfd (2)), | |
b6a7fd50 MK |
910 | we see (since Linux 3.8) |
911 | .\" commit 138d22b58696c506799f8de759804083ff9effae | |
912 | the following fields: | |
2dad4c59 | 913 | .IP |
f8a14cac | 914 | .in +4n |
37d5e699 | 915 | .EX |
f8a14cac MK |
916 | pos: 0 |
917 | flags: 02 | |
918 | mnt_id: 10 | |
919 | sigmask: 0000000000000006 | |
37d5e699 | 920 | .EE |
f8a14cac | 921 | .in |
2dad4c59 | 922 | .IP |
f8a14cac MK |
923 | .I sigmask |
924 | is the hexadecimal mask of signals that are accepted via this | |
925 | signalfd file descriptor. | |
926 | (In this example, bits 2 and 3 are set, corresponding to the signals | |
927 | .B SIGINT | |
928 | and | |
929 | .BR SIGQUIT ; | |
930 | see | |
931 | .BR signal (7).) | |
2dad4c59 | 932 | .IP |
4e77145c MK |
933 | For inotify file descriptors (see |
934 | .BR inotify (7)), | |
935 | we see (since Linux 3.8) | |
936 | the following fields: | |
2dad4c59 | 937 | .IP |
4e77145c | 938 | .in +4n |
37d5e699 | 939 | .EX |
4e77145c MK |
940 | pos: 0 |
941 | flags: 00 | |
942 | mnt_id: 11 | |
184d797d JW |
943 | inotify wd:2 ino:7ef82a sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:2af87e00220ffd73 |
944 | inotify wd:1 ino:192627 sdev:800001 mask:800afff ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:27261900802dfd73 | |
37d5e699 | 945 | .EE |
4e77145c | 946 | .in |
2dad4c59 | 947 | .IP |
4e77145c MK |
948 | Each of the lines beginning with "inotify" displays information about |
949 | one file or directory that is being monitored. | |
950 | The fields in this line are as follows: | |
951 | .RS | |
952 | .TP | |
953 | .I wd | |
954 | A watch descriptor number (in decimal). | |
955 | .TP | |
956 | .I ino | |
957 | The inode number of the target file (in hexadecimal). | |
958 | .TP | |
959 | .I sdev | |
960 | The ID of the device where the target file resides (in hexadecimal). | |
961 | .TP | |
962 | .I mask | |
963 | The mask of events being monitored for the target file (in hexadecimal). | |
964 | .RE | |
965 | .IP | |
966 | If the kernel was built with exportfs support, the path to the target | |
967 | file is exposed as a file handle, via three hexadecimal fields: | |
184d797d JW |
968 | .IR fhandle\-bytes , |
969 | .IR fhandle\-type , | |
4e77145c MK |
970 | and |
971 | .IR f_handle . | |
2dad4c59 | 972 | .IP |
e2444bcb MK |
973 | For fanotify file descriptors (see |
974 | .BR fanotify (7)), | |
975 | we see (since Linux 3.8) | |
976 | the following fields: | |
2dad4c59 | 977 | .IP |
e2444bcb | 978 | .in +4n |
37d5e699 | 979 | .EX |
e2444bcb MK |
980 | pos: 0 |
981 | flags: 02 | |
982 | mnt_id: 11 | |
184d797d JW |
983 | fanotify flags:0 event\-flags:88002 |
984 | fanotify ino:19264f sdev:800001 mflags:0 mask:1 ignored_mask:0 fhandle\-bytes:8 fhandle\-type:1 f_handle:4f261900a82dfd73 | |
37d5e699 | 985 | .EE |
e2444bcb | 986 | .in |
2dad4c59 | 987 | .IP |
e2444bcb MK |
988 | The fourth line displays information defined when the fanotify group |
989 | was created via | |
990 | .BR fanotify_init (2): | |
991 | .RS | |
992 | .TP | |
993 | .I flags | |
994 | The | |
995 | .I flags | |
996 | argument given to | |
997 | .BR fanotify_init (2) | |
998 | (expressed in hexadecimal). | |
999 | .TP | |
184d797d | 1000 | .I event\-flags |
e2444bcb MK |
1001 | The |
1002 | .I event_f_flags | |
1003 | argument given to | |
1004 | .BR fanotify_init (2) | |
1005 | (expressed in hexadecimal). | |
1006 | .RE | |
1007 | .IP | |
1008 | Each additional line shown in the file contains information | |
1009 | about one of the marks in the fanotify group. | |
1010 | Most of these fields are as for inotify, except: | |
1011 | .RS | |
1012 | .TP | |
1013 | .I mflags | |
1014 | The flags associated with the mark | |
1015 | (expressed in hexadecimal). | |
1016 | .TP | |
1017 | .I mask | |
1018 | The events mask for this mark | |
1019 | (expressed in hexadecimal). | |
1020 | .TP | |
1021 | .I ignored_mask | |
1022 | The mask of events that are ignored for this mark | |
1023 | (expressed in hexadecimal). | |
1024 | .RE | |
1025 | .IP | |
1026 | For details on these fields, see | |
1027 | .BR fanotify_mark (2). | |
340a16a6 LW |
1028 | .IP |
1029 | For timerfd file descriptors (see | |
1030 | .BR timerfd (2)), | |
1031 | we see (since Linux 3.17) | |
cd595f62 | 1032 | .\" commit af9c4957cf212ad9cf0bee34c95cb11de5426e85 |
340a16a6 LW |
1033 | the following fields: |
1034 | .IP | |
1035 | .in +4n | |
1036 | .EX | |
1037 | pos: 0 | |
1038 | flags: 02004002 | |
1039 | mnt_id: 13 | |
1040 | clockid: 0 | |
1041 | ticks: 0 | |
1042 | settime flags: 03 | |
1043 | it_value: (7695568592, 640020877) | |
1044 | it_interval: (0, 0) | |
1045 | .EE | |
1046 | .in | |
1cdbc3a6 MK |
1047 | .RS |
1048 | .TP | |
340a16a6 | 1049 | .I clockid |
1cdbc3a6 | 1050 | This is the numeric value of the clock ID |
734ec506 MK |
1051 | (corresponding to one of the |
1052 | .B CLOCK_* | |
1053 | constants defined via | |
a6425049 | 1054 | .IR <time.h> ) |
cb5a67a4 | 1055 | that is used to mark the progress of the timer (in this example, 0 is |
340a16a6 | 1056 | .BR CLOCK_REALTIME ). |
1cdbc3a6 | 1057 | .TP |
340a16a6 | 1058 | .I ticks |
1cdbc3a6 MK |
1059 | This is the number of timer expirations that have occurred, |
1060 | (i.e., the value that | |
340a16a6 | 1061 | .BR read (2) |
1cdbc3a6 MK |
1062 | on it would return). |
1063 | .TP | |
340a16a6 | 1064 | .I settime flags |
1cdbc3a6 | 1065 | This field lists the flags with which the timerfd was last armed (see |
340a16a6 LW |
1066 | .BR timerfd_settime (2)), |
1067 | in octal | |
1068 | (in this example, both | |
1069 | .B TFD_TIMER_ABSTIME | |
1070 | and | |
1071 | .B TFD_TIMER_CANCEL_ON_SET | |
1072 | are set). | |
1cdbc3a6 | 1073 | .TP |
340a16a6 | 1074 | .I it_value |
1cdbc3a6 MK |
1075 | This field contains the amount of time until the timer will next expire, |
1076 | expressed in seconds and nanoseconds. | |
734ec506 MK |
1077 | This is always expressed as a relative value, |
1078 | regardless of whether the timer was created using the | |
1079 | .B TFD_TIMER_ABSTIME | |
1080 | flag. | |
1cdbc3a6 | 1081 | .TP |
340a16a6 | 1082 | .I it_interval |
1cdbc3a6 MK |
1083 | This field contains the interval of the timer, |
1084 | in seconds and nanoseconds. | |
1085 | (The | |
1086 | .I it_value | |
1087 | and | |
1088 | .I it_interval | |
1089 | fields contain the values that | |
340a16a6 | 1090 | .BR timerfd_gettime (2) |
1cdbc3a6 MK |
1091 | on this file descriptor would return.) |
1092 | .RE | |
0ca2fc4d | 1093 | .TP |
93401860 MK |
1094 | .IR /proc/[pid]/gid_map " (since Linux 3.5)" |
1095 | See | |
1096 | .BR user_namespaces (7). | |
1097 | .TP | |
0ca2fc4d | 1098 | .IR /proc/[pid]/io " (since kernel 2.6.20)" |
68f11066 MK |
1099 | .\" commit 7c3ab7381e79dfc7db14a67c6f4f3285664e1ec2 |
1100 | This file contains I/O statistics for the process, for example: | |
37d5e699 | 1101 | .IP |
0ca2fc4d | 1102 | .in +4n |
37d5e699 | 1103 | .EX |
0ca2fc4d PS |
1104 | .RB "#" " cat /proc/3828/io" |
1105 | rchar: 323934931 | |
1106 | wchar: 323929600 | |
1107 | syscr: 632687 | |
1108 | syscw: 632675 | |
1109 | read_bytes: 0 | |
1110 | write_bytes: 323932160 | |
1111 | cancelled_write_bytes: 0 | |
37d5e699 | 1112 | .EE |
0ca2fc4d | 1113 | .in |
2dad4c59 | 1114 | .IP |
0ca2fc4d PS |
1115 | The fields are as follows: |
1116 | .RS | |
68f11066 MK |
1117 | .TP |
1118 | .IR rchar ": characters read" | |
0ca2fc4d PS |
1119 | The number of bytes which this task has caused to be read from storage. |
1120 | This is simply the sum of bytes which this process passed to | |
1121 | .BR read (2) | |
68f11066 | 1122 | and similar system calls. |
11256884 | 1123 | It includes things such as terminal I/O and |
68f11066 MK |
1124 | is unaffected by whether or not actual |
1125 | physical disk I/O was required (the read might have been satisfied from | |
0ca2fc4d | 1126 | pagecache). |
68f11066 MK |
1127 | .TP |
1128 | .IR wchar ": characters written" | |
0ca2fc4d PS |
1129 | The number of bytes which this task has caused, or shall cause to be written |
1130 | to disk. | |
1131 | Similar caveats apply here as with | |
1132 | .IR rchar . | |
68f11066 MK |
1133 | .TP |
1134 | .IR syscr ": read syscalls" | |
1135 | Attempt to count the number of read I/O operations\(emthat is, | |
1136 | system calls such as | |
0ca2fc4d PS |
1137 | .BR read (2) |
1138 | and | |
1139 | .BR pread (2). | |
68f11066 MK |
1140 | .TP |
1141 | .IR syscw ": write syscalls" | |
1142 | Attempt to count the number of write I/O operations\(emthat is, | |
1143 | system calls such as | |
0ca2fc4d PS |
1144 | .BR write (2) |
1145 | and | |
1146 | .BR pwrite (2). | |
68f11066 MK |
1147 | .TP |
1148 | .IR read_bytes ": bytes read" | |
0ca2fc4d PS |
1149 | Attempt to count the number of bytes which this process really did cause to |
1150 | be fetched from the storage layer. | |
1151 | This is accurate for block-backed filesystems. | |
68f11066 MK |
1152 | .TP |
1153 | .IR write_bytes ": bytes written" | |
0ca2fc4d PS |
1154 | Attempt to count the number of bytes which this process caused to be sent to |
1155 | the storage layer. | |
68f11066 | 1156 | .TP |
0ca2fc4d | 1157 | .IR cancelled_write_bytes : |
0ca2fc4d | 1158 | The big inaccuracy here is truncate. |
c7169ee5 | 1159 | If a process writes 1 MB to a file and then deletes the file, |
0ca2fc4d | 1160 | it will in fact perform no writeout. |
c7169ee5 | 1161 | But it will have been accounted as having caused 1 MB of write. |
68f11066 | 1162 | In other words: this field represents the number of bytes which this process |
0ca2fc4d | 1163 | caused to not happen, by truncating pagecache. |
68f11066 | 1164 | A task can cause "negative" I/O too. |
0ca2fc4d | 1165 | If this task truncates some dirty pagecache, |
68f11066 MK |
1166 | some I/O which another task has been accounted for |
1167 | (in its | |
1168 | .IR write_bytes ) | |
1169 | will not be happening. | |
1170 | .RE | |
0ca2fc4d PS |
1171 | .IP |
1172 | .IR Note : | |
68f11066 | 1173 | In the current implementation, things are a bit racy on 32-bit systems: |
0ca2fc4d PS |
1174 | if process A reads process B's |
1175 | .I /proc/[pid]/io | |
68f11066 | 1176 | while process B is updating one of these 64-bit counters, |
0ca2fc4d | 1177 | process A could see an intermediate result. |
2dad4c59 | 1178 | .IP |
d8e2972a MK |
1179 | Permission to access this file is governed by a ptrace access mode |
1180 | .B PTRACE_MODE_READ_FSCREDS | |
1181 | check; see | |
1182 | .BR ptrace (2). | |
f6e17121 | 1183 | .TP |
7e07d950 | 1184 | .IR /proc/[pid]/limits " (since Linux 2.6.24)" |
69ab425e MK |
1185 | This file displays the soft limit, hard limit, and units of measurement |
1186 | for each of the process's resource limits (see | |
1187 | .BR getrlimit (2)). | |
1188 | Up to and including Linux 2.6.35, | |
1189 | this file is protected to allow reading only by the real UID of the process. | |
1190 | Since Linux 2.6.36, | |
1191 | .\" commit 3036e7b490bf7878c6dae952eec5fb87b1106589 | |
1192 | this file is readable by all users on the system. | |
df2a8576 MK |
1193 | .\" FIXME Describe /proc/[pid]/loginuid |
1194 | .\" Added in 2.6.11; updating requires CAP_AUDIT_CONTROL | |
1195 | .\" CONFIG_AUDITSYSCALL | |
b4f89985 | 1196 | .TP |
0dbe186a | 1197 | .IR /proc/[pid]/map_files/ " (since kernel 3.3)" |
18cdd0ac MK |
1198 | .\" commit 640708a2cff7f81e246243b0073c66e6ece7e53e |
1199 | This subdirectory contains entries corresponding to memory-mapped | |
b4f89985 PE |
1200 | files (see |
1201 | .BR mmap (2)). | |
18cdd0ac MK |
1202 | Entries are named by memory region start and end |
1203 | address pair (expressed as hexadecimal numbers), | |
1204 | and are symbolic links to the mapped files themselves. | |
1205 | Here is an example, with the output wrapped and reformatted to fit on an 80-column display: | |
37d5e699 | 1206 | .IP |
b4f89985 | 1207 | .in +4n |
37d5e699 | 1208 | .EX |
184d797d | 1209 | .RB "#" " ls \-l /proc/self/map_files/" |
18cdd0ac | 1210 | lr\-\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:31 |
9bc87ed0 | 1211 | 3252e00000\-3252e20000 \-> /usr/lib64/ld\-2.15.so |
b4f89985 | 1212 | \&... |
37d5e699 | 1213 | .EE |
b4f89985 | 1214 | .in |
2dad4c59 | 1215 | .IP |
b4f89985 | 1216 | Although these entries are present for memory regions that were |
d6a56978 | 1217 | mapped with the |
b4f89985 | 1218 | .BR MAP_FILE |
18cdd0ac | 1219 | flag, the way anonymous shared memory (regions created with the |
b4f89985 PE |
1220 | .B MAP_ANON | MAP_SHARED |
1221 | flags) | |
1222 | is implemented in Linux | |
18cdd0ac MK |
1223 | means that such regions also appear on this directory. |
1224 | Here is an example where the target file is the deleted | |
1225 | .I /dev/zero | |
1226 | one: | |
37d5e699 | 1227 | .IP |
b4f89985 | 1228 | .in +4n |
37d5e699 | 1229 | .EX |
18cdd0ac MK |
1230 | lrw\-\-\-\-\-\-\-. 1 root root 64 Apr 16 21:33 |
1231 | 7fc075d2f000\-7fc075e6f000 \-> /dev/zero (deleted) | |
37d5e699 | 1232 | .EE |
b4f89985 | 1233 | .in |
2dad4c59 | 1234 | .IP |
6a036b00 KF |
1235 | Permission to access this file is governed by a ptrace access mode |
1236 | .B PTRACE_MODE_READ_FSCREDS | |
1237 | check; see | |
1238 | .BR ptrace (2). | |
1239 | .IP | |
84eb2279 MK |
1240 | Until kernel version 4.3, |
1241 | .\" commit bdb4d100afe9818aebd1d98ced575c5ef143456c | |
1242 | this directory appeared only if the | |
b4f89985 | 1243 | .B CONFIG_CHECKPOINT_RESTORE |
6a036b00 | 1244 | kernel configuration option was enabled. |
167f94b7 MK |
1245 | .IP |
1246 | Capabilities are required to read the contents of the symbolic links in | |
1247 | this directory: before Linux 5.9, the reading process requires | |
1248 | .BR CAP_SYS_ADMIN | |
1249 | in the initial user namespace; | |
1250 | since Linux 5.9, the reading process must have either | |
1251 | .BR CAP_SYS_ADMIN | |
1252 | or | |
1253 | .BR CAP_CHECKPOINT_RESTORE | |
1254 | in the user namespace where it resides. | |
fea681da | 1255 | .TP |
69119dc7 | 1256 | .I /proc/[pid]/maps |
fea681da MK |
1257 | A file containing the currently mapped memory regions and their access |
1258 | permissions. | |
bbf9f397 MK |
1259 | See |
1260 | .BR mmap (2) | |
1261 | for some further information about memory mappings. | |
2dad4c59 | 1262 | .IP |
aee2f0bf MK |
1263 | Permission to access this file is governed by a ptrace access mode |
1264 | .B PTRACE_MODE_READ_FSCREDS | |
1265 | check; see | |
1266 | .BR ptrace (2). | |
2dad4c59 | 1267 | .IP |
dd0c3b96 | 1268 | The format of the file is: |
c1a022dc | 1269 | .IP |
73942082 | 1270 | .in +4n |
c1a022dc | 1271 | .EX |
21781757 | 1272 | .I "address perms offset dev inode pathname" |
184d797d JW |
1273 | 00400000\-00452000 r\-xp 00000000 08:02 173521 /usr/bin/dbus\-daemon |
1274 | 00651000\-00652000 r\-\-p 00051000 08:02 173521 /usr/bin/dbus\-daemon | |
1275 | 00652000\-00655000 rw\-p 00052000 08:02 173521 /usr/bin/dbus\-daemon | |
1276 | 00e03000\-00e24000 rw\-p 00000000 00:00 0 [heap] | |
1277 | 00e24000\-011f7000 rw\-p 00000000 00:00 0 [heap] | |
182090db | 1278 | \&... |
184d797d JW |
1279 | 35b1800000\-35b1820000 r\-xp 00000000 08:02 135522 /usr/lib64/ld\-2.15.so |
1280 | 35b1a1f000\-35b1a20000 r\-\-p 0001f000 08:02 135522 /usr/lib64/ld\-2.15.so | |
1281 | 35b1a20000\-35b1a21000 rw\-p 00020000 08:02 135522 /usr/lib64/ld\-2.15.so | |
1282 | 35b1a21000\-35b1a22000 rw\-p 00000000 00:00 0 | |
1283 | 35b1c00000\-35b1dac000 r\-xp 00000000 08:02 135870 /usr/lib64/libc\-2.15.so | |
1284 | 35b1dac000\-35b1fac000 \-\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so | |
1285 | 35b1fac000\-35b1fb0000 r\-\-p 001ac000 08:02 135870 /usr/lib64/libc\-2.15.so | |
1286 | 35b1fb0000\-35b1fb2000 rw\-p 001b0000 08:02 135870 /usr/lib64/libc\-2.15.so | |
182090db | 1287 | \&... |
184d797d | 1288 | f2c6ff8c000\-7f2c7078c000 rw\-p 00000000 00:00 0 [stack:986] |
182090db | 1289 | \&... |
184d797d JW |
1290 | 7fffb2c0d000\-7fffb2c2e000 rw\-p 00000000 00:00 0 [stack] |
1291 | 7fffb2d48000\-7fffb2d49000 r\-xp 00000000 00:00 0 [vdso] | |
c1a022dc | 1292 | .EE |
21781757 | 1293 | .in |
c1a022dc | 1294 | .IP |
7d2e6d74 | 1295 | The |
3eb8c588 MK |
1296 | .I address |
1297 | field is the address space in the process that the mapping occupies. | |
1298 | The | |
1299 | .I perms | |
1300 | field is a set of permissions: | |
2dad4c59 | 1301 | .IP |
161b8eda | 1302 | .in +4n |
37d5e699 | 1303 | .EX |
fea681da MK |
1304 | r = read |
1305 | w = write | |
1306 | x = execute | |
1307 | s = shared | |
1308 | p = private (copy on write) | |
37d5e699 | 1309 | .EE |
fea681da | 1310 | .in |
2dad4c59 | 1311 | .IP |
3eb8c588 MK |
1312 | The |
1313 | .I offset | |
b844cf04 | 1314 | field is the offset into the file/whatever; |
3eb8c588 MK |
1315 | .I dev |
1316 | is the device | |
dd0c3b96 | 1317 | (major:minor); |
3eb8c588 MK |
1318 | .I inode |
1319 | is the inode on that device. | |
59a40ed7 | 1320 | 0 indicates that no inode is associated with the memory region, |
16e64bae | 1321 | as would be the case with BSS (uninitialized data). |
2dad4c59 | 1322 | .IP |
3eb8c588 MK |
1323 | The |
1324 | .I pathname | |
1325 | field will usually be the file that is backing the mapping. | |
491ea6f1 | 1326 | For ELF files, |
3eb8c588 MK |
1327 | you can easily coordinate with the |
1328 | .I offset | |
1329 | field by looking at the | |
491ea6f1 MK |
1330 | Offset field in the ELF program headers |
1331 | .RI ( "readelf\ \-l" ). | |
2dad4c59 | 1332 | .IP |
491ea6f1 | 1333 | There are additional helpful pseudo-paths: |
0019177e | 1334 | .RS |
61b0b1f4 MK |
1335 | .TP |
1336 | .IR [stack] | |
16e64bae | 1337 | The initial process's (also known as the main thread's) stack. |
61b0b1f4 | 1338 | .TP |
bca7fbb5 MK |
1339 | .IR [stack:<tid>] " (from Linux 3.4 to 4.4)" |
1340 | .\" commit b76437579d1344b612cf1851ae610c636cec7db0 (added) | |
1341 | .\" commit 65376df582174ffcec9e6471bf5b0dd79ba05e4a (removed) | |
61b0b1f4 | 1342 | A thread's stack (where the |
3eb8c588 | 1343 | .IR <tid> |
61b0b1f4 | 1344 | is a thread ID). |
491ea6f1 | 1345 | It corresponds to the |
3eb8c588 | 1346 | .IR /proc/[pid]/task/[tid]/ |
37d32c38 | 1347 | path. |
bca7fbb5 MK |
1348 | This field was removed in Linux 4.5, since providing this information |
1349 | for a process with large numbers of threads is expensive. | |
61b0b1f4 | 1350 | .TP |
7d2e6d74 | 1351 | .IR [vdso] |
61b0b1f4 | 1352 | The virtual dynamically linked shared object. |
c56a0185 MK |
1353 | See |
1354 | .BR vdso (7). | |
61b0b1f4 | 1355 | .TP |
7d2e6d74 | 1356 | .IR [heap] |
61b0b1f4 MK |
1357 | The process's heap. |
1358 | .in | |
61b0b1f4 MK |
1359 | .RE |
1360 | .IP | |
3eb8c588 MK |
1361 | If the |
1362 | .I pathname | |
1363 | field is blank, | |
40382e5e MK |
1364 | this is an anonymous mapping as obtained via |
1365 | .BR mmap (2). | |
61b0b1f4 MK |
1366 | There is no easy way to coordinate this back to a process's source, |
1367 | short of running it through | |
491ea6f1 MK |
1368 | .BR gdb (1), |
1369 | .BR strace (1), | |
1370 | or similar. | |
2dad4c59 | 1371 | .IP |
b6547479 EK |
1372 | .I pathname |
1373 | is shown unescaped except for newline characters, which are replaced | |
d512e7b4 MK |
1374 | with an octal escape sequence. |
1375 | As a result, it is not possible to determine whether the original | |
1376 | pathname contained a newline character or the literal | |
9363af08 | 1377 | .I \e012 |
b6547479 EK |
1378 | character sequence. |
1379 | .IP | |
1380 | If the mapping is file-backed and the file has been deleted, the string | |
d512e7b4 MK |
1381 | " (deleted)" is appended to the pathname. |
1382 | Note that this is ambiguous too. | |
b6547479 | 1383 | .IP |
eb9a0b2f | 1384 | Under Linux 2.0, there is no field giving pathname. |
fea681da | 1385 | .TP |
69119dc7 | 1386 | .I /proc/[pid]/mem |
fea681da MK |
1387 | This file can be used to access the pages of a process's memory through |
1388 | .BR open (2), | |
1389 | .BR read (2), | |
1390 | and | |
ccb2bb0d | 1391 | .BR lseek (2). |
2dad4c59 | 1392 | .IP |
aee2f0bf MK |
1393 | Permission to access this file is governed by a ptrace access mode |
1394 | .B PTRACE_MODE_ATTACH_FSCREDS | |
1395 | check; see | |
1396 | .BR ptrace (2). | |
b4e9ee8f | 1397 | .TP |
69119dc7 | 1398 | .IR /proc/[pid]/mountinfo " (since Linux 2.6.26)" |
b4e9ee8f | 1399 | .\" This info adapted from Documentation/filesystems/proc.txt |
fb4bdaa1 | 1400 | .\" commit 2d4d4864ac08caff5c204a752bd004eed4f08760 |
525a8b54 | 1401 | This file contains information about mounts |
ef5b47f6 MK |
1402 | in the process's mount namespace (see |
1403 | .BR mount_namespaces (7)). | |
fb4bdaa1 MK |
1404 | It supplies various information |
1405 | (e.g., propagation state, root of mount for bind mounts, | |
1406 | identifier for each mount and its parent) that is missing from the (older) | |
1407 | .IR /proc/[pid]/mounts | |
1408 | file, and fixes various other problems with that file | |
1409 | (e.g., nonextensibility, | |
1410 | failure to distinguish per-mount versus per-superblock options). | |
2dad4c59 | 1411 | .IP |
fb4bdaa1 | 1412 | The file contains lines of the form: |
c1a022dc | 1413 | .IP |
c1a022dc | 1414 | .EX |
0f619d1f | 1415 | 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 \- ext3 /dev/root rw,errors=continue |
b4e9ee8f | 1416 | (1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11) |
c1a022dc | 1417 | .EE |
b4e9ee8f MK |
1418 | .IP |
1419 | The numbers in parentheses are labels for the descriptions below: | |
3bc960c2 | 1420 | .RS 7 |
b4e9ee8f MK |
1421 | .TP 5 |
1422 | (1) | |
0f619d1f | 1423 | mount ID: a unique ID for the mount (may be reused after |
b4e9ee8f MK |
1424 | .BR umount (2)). |
1425 | .TP | |
1426 | (2) | |
29270550 MK |
1427 | parent ID: the ID of the parent mount |
1428 | (or of self for the root of this mount namespace's mount tree). | |
1429 | .IP | |
8c420ed8 MK |
1430 | If a new mount is stacked on top of a previous existing mount |
1431 | (so that it hides the existing mount) at pathname P, | |
1432 | then the parent of the new mount is the previous mount at that location. | |
1433 | Thus, when looking at all the mounts stacked at a particular location, | |
1434 | the top-most mount is the one that is not the parent | |
1435 | of any other mount at the same location. | |
1436 | (Note, however, that this top-most mount will be accessible only if | |
1437 | the longest path subprefix of P that is a mount point | |
1438 | is not itself hidden by a stacked mount.) | |
1439 | .IP | |
525a8b54 | 1440 | If the parent mount lies outside the process's root directory (see |
29270550 MK |
1441 | .BR chroot (2)), |
1442 | the ID shown here won't have a corresponding record in | |
35cf1b93 | 1443 | .I mountinfo |
29270550 | 1444 | whose mount ID (field 1) matches this parent mount ID |
525a8b54 | 1445 | (because mounts that lie outside the process's root directory |
29270550 MK |
1446 | are not shown in |
1447 | .IR mountinfo ). | |
1448 | As a special case of this point, | |
525a8b54 | 1449 | the process's root mount may have a parent mount |
29270550 MK |
1450 | (for the initramfs filesystem) that lies |
1451 | .\" Miklos Szeredi, Nov 2017: The hidden one is the initramfs, I believe | |
1452 | .\" mtk: In the initial mount namespace, this hidden ID has the value 0 | |
1453 | outside the process's root directory, | |
525a8b54 | 1454 | and an entry for that mount will not appear in |
29270550 | 1455 | .IR mountinfo . |
b4e9ee8f MK |
1456 | .TP |
1457 | (3) | |
0f619d1f | 1458 | major:minor: the value of |
b4e9ee8f | 1459 | .I st_dev |
0f619d1f | 1460 | for files on this filesystem (see |
b4e9ee8f MK |
1461 | .BR stat (2)). |
1462 | .TP | |
1463 | (4) | |
0f619d1f | 1464 | root: the pathname of the directory in the filesystem |
8d857fcb | 1465 | which forms the root of this mount. |
b4e9ee8f MK |
1466 | .TP |
1467 | (5) | |
ebdc66e2 | 1468 | mount point: the pathname of the mount point relative |
0f619d1f | 1469 | to the process's root directory. |
b4e9ee8f MK |
1470 | .TP |
1471 | (6) | |
adab7ac8 MK |
1472 | mount options: per-mount options (see |
1473 | .BR mount (2)). | |
b4e9ee8f MK |
1474 | .TP |
1475 | (7) | |
0f619d1f | 1476 | optional fields: zero or more fields of the form "tag[:value]"; see below. |
b4e9ee8f MK |
1477 | .TP |
1478 | (8) | |
0f619d1f | 1479 | separator: the end of the optional fields is marked by a single hyphen. |
b4e9ee8f MK |
1480 | .TP |
1481 | (9) | |
0f619d1f | 1482 | filesystem type: the filesystem type in the form "type[.subtype]". |
b4e9ee8f MK |
1483 | .TP |
1484 | (10) | |
9ee4a2b6 | 1485 | mount source: filesystem-specific information or "none". |
b4e9ee8f MK |
1486 | .TP |
1487 | (11) | |
adab7ac8 MK |
1488 | super options: per-superblock options (see |
1489 | .BR mount (2)). | |
b4e9ee8f MK |
1490 | .RE |
1491 | .IP | |
966b5839 MK |
1492 | Currently, the possible optional fields are |
1493 | .IR shared , | |
1494 | .IR master , | |
1495 | .IR propagate_from , | |
1496 | and | |
1497 | .IR unbindable . | |
1498 | See | |
1499 | .BR mount_namespaces (7) | |
1500 | for a description of these fields. | |
0f619d1f MK |
1501 | Parsers should ignore all unrecognized optional fields. |
1502 | .IP | |
8a5fc410 MK |
1503 | For more information on mount propagation see |
1504 | .I Documentation/filesystems/sharedsubtree.rst | |
1505 | (or | |
b4e9ee8f | 1506 | .I Documentation/filesystems/sharedsubtree.txt |
8a5fc410 | 1507 | before Linux 5.8) |
66a9882e | 1508 | in the Linux kernel source tree. |
b4e9ee8f | 1509 | .TP |
cea61382 | 1510 | .IR /proc/[pid]/mounts " (since Linux 2.4.19)" |
226cb3a8 | 1511 | This file lists all the filesystems currently mounted in the |
ef5b47f6 MK |
1512 | process's mount namespace (see |
1513 | .BR mount_namespaces (7)). | |
cea61382 MK |
1514 | The format of this file is documented in |
1515 | .BR fstab (5). | |
2dad4c59 | 1516 | .IP |
cea61382 MK |
1517 | Since kernel version 2.6.15, this file is pollable: |
1518 | after opening the file for reading, a change in this file | |
9ee4a2b6 | 1519 | (i.e., a filesystem mount or unmount) causes |
cea61382 | 1520 | .BR select (2) |
226cb3a8 | 1521 | to mark the file descriptor as having an exceptional condition, and |
cea61382 MK |
1522 | .BR poll (2) |
1523 | and | |
1524 | .BR epoll_wait (2) | |
226cb3a8 MK |
1525 | mark the file as having a priority event |
1526 | .RB ( POLLPRI ). | |
1527 | (Before Linux 2.6.30, | |
1528 | a change in this file was indicated by the file descriptor | |
1529 | being marked as readable for | |
1530 | .BR select (2), | |
1531 | and being marked as having an error condition for | |
1532 | .BR poll (2) | |
1533 | and | |
1534 | .BR epoll_wait (2).) | |
cea61382 | 1535 | .TP |
69119dc7 | 1536 | .IR /proc/[pid]/mountstats " (since Linux 2.6.17)" |
783a6233 | 1537 | This file exports information (statistics, configuration information) |
525a8b54 | 1538 | about the mounts in the process's mount namespace (see |
ef5b47f6 | 1539 | .BR mount_namespaces (7)). |
b4e9ee8f | 1540 | Lines in this file have the form: |
37d5e699 MK |
1541 | .IP |
1542 | .in +4n | |
1543 | .EX | |
31572c71 MK |
1544 | device /dev/sda7 mounted on /home with fstype ext3 [stats] |
1545 | ( 1 ) ( 2 ) (3 ) ( 4 ) | |
37d5e699 MK |
1546 | .EE |
1547 | .in | |
b4e9ee8f MK |
1548 | .IP |
1549 | The fields in each line are: | |
3bc960c2 | 1550 | .RS 7 |
b4e9ee8f MK |
1551 | .TP 5 |
1552 | (1) | |
1553 | The name of the mounted device | |
1554 | (or "nodevice" if there is no corresponding device). | |
1555 | .TP | |
1556 | (2) | |
9ee4a2b6 | 1557 | The mount point within the filesystem tree. |
b4e9ee8f MK |
1558 | .TP |
1559 | (3) | |
9ee4a2b6 | 1560 | The filesystem type. |
b4e9ee8f MK |
1561 | .TP |
1562 | (4) | |
1563 | Optional statistics and configuration information. | |
9ee4a2b6 | 1564 | Currently (as at Linux 2.6.26), only NFS filesystems export |
b4e9ee8f MK |
1565 | information via this field. |
1566 | .RE | |
1567 | .IP | |
90878f7c | 1568 | This file is readable only by the owner of the process. |
b4e9ee8f | 1569 | .TP |
2d3fb75b | 1570 | .IR /proc/[pid]/net " (since Linux 2.6.25)" |
9fb88bc8 MK |
1571 | See the description of |
1572 | .IR /proc/net . | |
1573 | .TP | |
b4a185e5 | 1574 | .IR /proc/[pid]/ns/ " (since Linux 3.0)" |
2c4201f0 | 1575 | .\" See commit 6b4e306aa3dc94a0545eb9279475b1ab6209a31f |
b4a185e5 EB |
1576 | This is a subdirectory containing one entry for each namespace that |
1577 | supports being manipulated by | |
80e63655 | 1578 | .BR setns (2). |
cf8bfe6d MK |
1579 | For more information, see |
1580 | .BR namespaces (7). | |
b4a185e5 | 1581 | .TP |
69119dc7 | 1582 | .IR /proc/[pid]/numa_maps " (since Linux 2.6.14)" |
610f75cc MK |
1583 | See |
1584 | .BR numa (7). | |
7388733a | 1585 | .TP |
69119dc7 | 1586 | .IR /proc/[pid]/oom_adj " (since Linux 2.6.11)" |
b4e9ee8f | 1587 | This file can be used to adjust the score used to select which process |
0425de01 | 1588 | should be killed in an out-of-memory (OOM) situation. |
b4e9ee8f MK |
1589 | The kernel uses this value for a bit-shift operation of the process's |
1590 | .IR oom_score | |
1591 | value: | |
5b8dbfd4 MK |
1592 | valid values are in the range \-16 to +15, |
1593 | plus the special value \-17, | |
b4e9ee8f MK |
1594 | which disables OOM-killing altogether for this process. |
1595 | A positive score increases the likelihood of this | |
1596 | process being killed by the OOM-killer; | |
1597 | a negative score decreases the likelihood. | |
de8e9cc1 | 1598 | .IP |
b4e9ee8f MK |
1599 | The default value for this file is 0; |
1600 | a new process inherits its parent's | |
1601 | .I oom_adj | |
1602 | setting. | |
1603 | A process must be privileged | |
1604 | .RB ( CAP_SYS_RESOURCE ) | |
1605 | to update this file. | |
f2c8b197 MK |
1606 | .IP |
1607 | Since Linux 2.6.36, use of this file is deprecated in favor of | |
1608 | .IR /proc/[pid]/oom_score_adj . | |
b4e9ee8f | 1609 | .TP |
69119dc7 | 1610 | .IR /proc/[pid]/oom_score " (since Linux 2.6.11)" |
5753354a MF |
1611 | .\" See mm/oom_kill.c::badness() in pre 2.6.36 sources |
1612 | .\" See mm/oom_kill.c::oom_badness() after 2.6.36 | |
1613 | .\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10 | |
b4e9ee8f MK |
1614 | This file displays the current score that the kernel gives to |
1615 | this process for the purpose of selecting a process | |
1616 | for the OOM-killer. | |
1617 | A higher score means that the process is more likely to be | |
1618 | selected by the OOM-killer. | |
1619 | The basis for this score is the amount of memory used by the process, | |
1620 | with increases (+) or decreases (\-) for factors including: | |
5753354a MF |
1621 | .\" See mm/oom_kill.c::badness() in pre 2.6.36 sources |
1622 | .\" See mm/oom_kill.c::oom_badness() after 2.6.36 | |
1623 | .\" commit a63d83f427fbce97a6cea0db2e64b0eb8435cd10 | |
1624 | .RS | |
1625 | .IP * 2 | |
9b0e3937 | 1626 | whether the process is privileged (\-). |
5753354a MF |
1627 | .\" More precisely, if it has CAP_SYS_ADMIN or (pre 2.6.36) CAP_SYS_RESOURCE |
1628 | .RE | |
1629 | .IP | |
1630 | Before kernel 2.6.36 the following factors were also used in the calculation of oom_score: | |
b4e9ee8f MK |
1631 | .RS |
1632 | .IP * 2 | |
1633 | whether the process creates a lot of children using | |
1634 | .BR fork (2) | |
1635 | (+); | |
1636 | .IP * | |
1637 | whether the process has been running a long time, | |
1638 | or has used a lot of CPU time (\-); | |
1639 | .IP * | |
5753354a | 1640 | whether the process has a low nice value (i.e., > 0) (+); and |
b4e9ee8f MK |
1641 | .IP * |
1642 | whether the process is making direct hardware access (\-). | |
1643 | .\" More precisely, if it has CAP_SYS_RAWIO | |
1644 | .RE | |
1645 | .IP | |
1646 | The | |
1647 | .I oom_score | |
f2c8b197 MK |
1648 | also reflects the adjustment specified by the |
1649 | .I oom_score_adj | |
1650 | or | |
b4e9ee8f MK |
1651 | .I oom_adj |
1652 | setting for the process. | |
f2c8b197 MK |
1653 | .TP |
1654 | .IR /proc/[pid]/oom_score_adj " (since Linux 2.6.36)" | |
1655 | .\" Text taken from 3.7 Documentation/filesystems/proc.txt | |
1656 | This file can be used to adjust the badness heuristic used to select which | |
1657 | process gets killed in out-of-memory conditions. | |
2dad4c59 | 1658 | .IP |
f2c8b197 MK |
1659 | The badness heuristic assigns a value to each candidate task ranging from 0 |
1660 | (never kill) to 1000 (always kill) to determine which process is targeted. | |
1661 | The units are roughly a proportion along that range of | |
1662 | allowed memory the process may allocate from, | |
1663 | based on an estimation of its current memory and swap use. | |
1664 | For example, if a task is using all allowed memory, | |
1665 | its badness score will be 1000. | |
1666 | If it is using half of its allowed memory, its score will be 500. | |
2dad4c59 | 1667 | .IP |
f2c8b197 MK |
1668 | There is an additional factor included in the badness score: root |
1669 | processes are given 3% extra memory over other tasks. | |
2dad4c59 | 1670 | .IP |
f2c8b197 | 1671 | The amount of "allowed" memory depends on the context |
0633f951 | 1672 | in which the OOM-killer was called. |
f2c8b197 MK |
1673 | If it is due to the memory assigned to the allocating task's cpuset |
1674 | being exhausted, | |
1675 | the allowed memory represents the set of mems assigned to that | |
1676 | cpuset (see | |
1677 | .BR cpuset (7)). | |
1678 | If it is due to a mempolicy's node(s) being exhausted, | |
1679 | the allowed memory represents the set of mempolicy nodes. | |
1680 | If it is due to a memory limit (or swap limit) being reached, | |
1681 | the allowed memory is that configured limit. | |
1682 | Finally, if it is due to the entire system being out of memory, the | |
1683 | allowed memory represents all allocatable resources. | |
2dad4c59 | 1684 | .IP |
f2c8b197 | 1685 | The value of |
0633f951 | 1686 | .I oom_score_adj |
f2c8b197 MK |
1687 | is added to the badness score before it |
1688 | is used to determine which task to kill. | |
1689 | Acceptable values range from \-1000 | |
1690 | (OOM_SCORE_ADJ_MIN) to +1000 (OOM_SCORE_ADJ_MAX). | |
0633f951 | 1691 | This allows user space to control the preference for OOM-killing, |
f2c8b197 | 1692 | ranging from always preferring a certain |
a45168bf | 1693 | task or completely disabling it from OOM-killing. |
f2c8b197 | 1694 | The lowest possible value, \-1000, is |
0633f951 | 1695 | equivalent to disabling OOM-killing entirely for that task, |
f2c8b197 | 1696 | since it will always report a badness score of 0. |
2dad4c59 | 1697 | .IP |
f2c8b197 MK |
1698 | Consequently, it is very simple for user space to define |
1699 | the amount of memory to consider for each task. | |
48ac01a7 | 1700 | Setting an |
f2c8b197 MK |
1701 | .I oom_score_adj |
1702 | value of +500, for example, | |
1703 | is roughly equivalent to allowing the remainder of tasks sharing the | |
1704 | same system, cpuset, mempolicy, or memory controller resources | |
1705 | to use at least 50% more memory. | |
1706 | A value of \-500, on the other hand, would be roughly | |
1707 | equivalent to discounting 50% of the task's | |
1708 | allowed memory from being considered as scoring against the task. | |
2dad4c59 | 1709 | .IP |
0633f951 | 1710 | For backward compatibility with previous kernels, |
f2c8b197 MK |
1711 | .I /proc/[pid]/oom_adj |
1712 | can still be used to tune the badness score. | |
1713 | Its value is | |
9f1b9726 | 1714 | scaled linearly with |
f2c8b197 | 1715 | .IR oom_score_adj . |
2dad4c59 | 1716 | .IP |
f2c8b197 MK |
1717 | Writing to |
1718 | .IR /proc/[pid]/oom_score_adj | |
1719 | or | |
1720 | .IR /proc/[pid]/oom_adj | |
1721 | will change the other with its scaled value. | |
6f752251 MK |
1722 | .IP |
1723 | The | |
1724 | .BR choom (1) | |
1725 | program provides a command-line interface for adjusting the | |
1726 | .I oom_score_adj | |
1727 | value of a running process or a newly executed command. | |
b0aa1e51 MK |
1728 | .TP |
1729 | .IR /proc/[pid]/pagemap " (since Linux 2.6.25)" | |
1730 | This file shows the mapping of each of the process's virtual pages | |
1731 | into physical page frames or swap area. | |
1732 | It contains one 64-bit value for each virtual page, | |
1733 | with the bits set as follows: | |
0019177e | 1734 | .RS |
b0aa1e51 MK |
1735 | .TP |
1736 | 63 | |
1737 | If set, the page is present in RAM. | |
1738 | .TP | |
1739 | 62 | |
1740 | If set, the page is in swap space | |
1741 | .TP | |
1742 | 61 (since Linux 3.5) | |
1743 | The page is a file-mapped page or a shared anonymous page. | |
1744 | .TP | |
2e84528d | 1745 | 60\(en57 (since Linux 3.11) |
b0aa1e51 MK |
1746 | Zero |
1747 | .\" Not quite true; see commit 541c237c0923f567c9c4cabb8a81635baadc713f | |
1748 | .TP | |
2e84528d | 1749 | 56 (since Linux 4.2) |
abfbcb56 MK |
1750 | .\" commit 77bb499bb60f4b79cca7d139c8041662860fcf87 |
1751 | .\" commit 83b4b0bb635eee2b8e075062e4e008d1bc110ed7 | |
2e84528d OE |
1752 | The page is exclusively mapped. |
1753 | .TP | |
b5301584 | 1754 | 55 (since Linux 3.11) |
b0aa1e51 MK |
1755 | PTE is soft-dirty |
1756 | (see the kernel source file | |
184d797d | 1757 | .IR Documentation/admin\-guide/mm/soft\-dirty.rst ). |
b0aa1e51 | 1758 | .TP |
9bc87ed0 | 1759 | 54\(en0 |
b0aa1e51 MK |
1760 | If the page is present in RAM (bit 63), then these bits |
1761 | provide the page frame number, which can be used to index | |
1762 | .IR /proc/kpageflags | |
1763 | and | |
1764 | .IR /proc/kpagecount . | |
1765 | If the page is present in swap (bit 62), | |
9bc87ed0 | 1766 | then bits 4\(en0 give the swap type, and bits 54\(en5 encode the swap offset. |
b0aa1e51 MK |
1767 | .RE |
1768 | .IP | |
9bc87ed0 | 1769 | Before Linux 3.11, bits 60\(en55 were |
b0aa1e51 MK |
1770 | used to encode the base-2 log of the page size. |
1771 | .IP | |
1772 | To employ | |
1773 | .IR /proc/[pid]/pagemap | |
1774 | efficiently, use | |
1775 | .IR /proc/[pid]/maps | |
1776 | to determine which areas of memory are actually mapped and seek | |
1777 | to skip over unmapped regions. | |
1778 | .IP | |
1779 | The | |
1780 | .IR /proc/[pid]/pagemap | |
1781 | file is present only if the | |
1782 | .B CONFIG_PROC_PAGE_MONITOR | |
1783 | kernel configuration option is enabled. | |
2dad4c59 | 1784 | .IP |
aee2f0bf MK |
1785 | Permission to access this file is governed by a ptrace access mode |
1786 | .B PTRACE_MODE_READ_FSCREDS | |
1787 | check; see | |
1788 | .BR ptrace (2). | |
7c2905d1 MK |
1789 | .TP |
1790 | .IR /proc/[pid]/personality " (since Linux 2.6.28)" | |
1791 | .\" commit 478307230810d7e2a753ed220db9066dfdf88718 | |
1792 | This read-only file exposes the process's execution domain, as set by | |
1793 | .BR personality (2). | |
1794 | The value is displayed in hexadecimal notation. | |
2dad4c59 | 1795 | .IP |
4834ae91 MK |
1796 | Permission to access this file is governed by a ptrace access mode |
1797 | .B PTRACE_MODE_ATTACH_FSCREDS | |
1798 | check; see | |
1799 | .BR ptrace (2). | |
fea681da | 1800 | .TP |
69119dc7 | 1801 | .I /proc/[pid]/root |
008f1ecc | 1802 | UNIX and Linux support the idea of a per-process root of the |
9ee4a2b6 | 1803 | filesystem, set by the |
fea681da | 1804 | .BR chroot (2) |
c13182ef MK |
1805 | system call. |
1806 | This file is a symbolic link that points to the process's | |
14d70713 MK |
1807 | root directory, and behaves in the same way as |
1808 | .IR exe , | |
1809 | and | |
1810 | .IR fd/* . | |
2dad4c59 | 1811 | .IP |
948f0ff4 | 1812 | Note however that this file is not merely a symbolic link. |
2b312241 MF |
1813 | It provides the same view of the filesystem (including namespaces and the |
1814 | set of per-process mounts) as the process itself. | |
a77efd58 MK |
1815 | An example illustrates this point. |
1816 | In one terminal, we start a shell in new user and mount namespaces, | |
525a8b54 | 1817 | and in that shell we create some new mounts: |
2dad4c59 | 1818 | .IP |
a77efd58 | 1819 | .in +4n |
37d5e699 | 1820 | .EX |
861d36ba | 1821 | $ \fBPS1=\(aqsh1# \(aq unshare \-Urnm\fP |
a77efd58 MK |
1822 | sh1# \fBmount \-t tmpfs tmpfs /etc\fP # Mount empty tmpfs at /etc |
1823 | sh1# \fBmount \-\-bind /usr /dev\fP # Mount /usr at /dev | |
89f92905 | 1824 | sh1# \fBecho $$\fP |
a77efd58 | 1825 | 27123 |
37d5e699 | 1826 | .EE |
a77efd58 | 1827 | .in |
2dad4c59 | 1828 | .IP |
a77efd58 MK |
1829 | In a second terminal window, in the initial mount namespace, |
1830 | we look at the contents of the corresponding mounts in | |
1831 | the initial and new namespaces: | |
2dad4c59 | 1832 | .IP |
a77efd58 | 1833 | .in +4n |
37d5e699 | 1834 | .EX |
861d36ba | 1835 | $ \fBPS1=\(aqsh2# \(aq sudo sh\fP |
a77efd58 MK |
1836 | sh2# \fBls /etc | wc \-l\fP # In initial NS |
1837 | 309 | |
1838 | sh2# \fBls /proc/27123/root/etc | wc \-l\fP # /etc in other NS | |
1839 | 0 # The empty tmpfs dir | |
1840 | sh2# \fBls /dev | wc \-l\fP # In initial NS | |
1841 | 205 | |
1842 | sh2# \fBls /proc/27123/root/dev | wc \-l\fP # /dev in other NS | |
1843 | 11 # Actually bind | |
1844 | # mounted to /usr | |
1845 | sh2# \fBls /usr | wc \-l\fP # /usr in initial NS | |
1846 | 11 | |
37d5e699 | 1847 | .EE |
a77efd58 | 1848 | .in |
2dad4c59 | 1849 | .IP |
afcaf646 | 1850 | .\" The following was still true as at kernel 2.6.13 |
3ed7270e MK |
1851 | In a multithreaded process, the contents of the |
1852 | .I /proc/[pid]/root | |
1853 | symbolic link are not available if the main thread has already terminated | |
afcaf646 MK |
1854 | (typically by calling |
1855 | .BR pthread_exit (3)). | |
2dad4c59 | 1856 | .IP |
b902fe18 MK |
1857 | Permission to dereference or read |
1858 | .RB ( readlink (2)) | |
1859 | this symbolic link is governed by a ptrace access mode | |
1860 | .B PTRACE_MODE_READ_FSCREDS | |
1861 | check; see | |
1862 | .BR ptrace (2). | |
8273bf01 MK |
1863 | .TP |
1864 | .IR /proc/[pid]/projid_map " (since Linux 3.7)" | |
43d42cc0 | 1865 | .\" commit f76d207a66c3a53defea67e7d36c3eb1b7d6d61d |
8273bf01 MK |
1866 | See |
1867 | .BR user_namespaces (7). | |
15869389 MK |
1868 | .TP |
1869 | .IR /proc/[pid]/seccomp " (Linux 2.6.12 to 2.6.22)" | |
1870 | This file can be used to read and change the process's | |
1871 | secure computing (seccomp) mode setting. | |
1872 | It contains the value 0 if the process is not in seccomp mode, | |
1873 | and 1 if the process is in strict seccomp mode (see | |
1874 | .BR seccomp (2)). | |
1875 | Writing 1 to this file places the process irreversibly in strict seccomp mode. | |
1876 | (Further attempts to write to the file fail with the | |
1877 | .B EPERM | |
1878 | error.) | |
2dad4c59 | 1879 | .IP |
15869389 MK |
1880 | In Linux 2.6.23, |
1881 | this file went away, to be replaced by the | |
1882 | .BR prctl (2) | |
1883 | .BR PR_GET_SECCOMP | |
1884 | and | |
1885 | .BR PR_SET_SECCOMP | |
1886 | operations (and later by | |
1887 | .BR seccomp (2) | |
1888 | and the | |
1889 | .I Seccomp | |
1890 | field in | |
1891 | .IR /proc/[pid]/status ). | |
69119dc7 | 1892 | .\" FIXME Describe /proc/[pid]/sessionid |
b3fb99e8 | 1893 | .\" commit 1e0bd7550ea9cf474b1ad4c6ff5729a507f75fdc |
b4e9ee8f | 1894 | .\" CONFIG_AUDITSYSCALL |
43d42cc0 | 1895 | .\" Added in 2.6.25; read-only; only readable by real UID |
bea08fec | 1896 | .\" |
69119dc7 | 1897 | .\" FIXME Describe /proc/[pid]/sched |
b4e9ee8f MK |
1898 | .\" Added in 2.6.23 |
1899 | .\" CONFIG_SCHED_DEBUG, and additional fields if CONFIG_SCHEDSTATS | |
1900 | .\" Displays various scheduling parameters | |
1901 | .\" This file can be written, to reset stats | |
ef4f4031 | 1902 | .\" The set of fields exposed by this file have changed |
b3fb99e8 MK |
1903 | .\" significantly over time. |
1904 | .\" commit 43ae34cb4cd650d1eb4460a8253a8e747ba052ac | |
1905 | .\" | |
69119dc7 MK |
1906 | .\" FIXME Describe /proc/[pid]/schedstats and |
1907 | .\" /proc/[pid]/task/[tid]/schedstats | |
b4e9ee8f MK |
1908 | .\" Added in 2.6.9 |
1909 | .\" CONFIG_SCHEDSTATS | |
fea681da | 1910 | .TP |
5c92b1b7 | 1911 | .IR /proc/[pid]/setgroups " (since Linux 3.19)" |
ab28dba9 MK |
1912 | See |
1913 | .BR user_namespaces (7). | |
d520465b | 1914 | .TP |
69119dc7 | 1915 | .IR /proc/[pid]/smaps " (since Linux 2.6.14)" |
b07b19c4 | 1916 | This file shows memory consumption for each of the process's mappings. |
859503c3 MK |
1917 | (The |
1918 | .BR pmap (1) | |
1919 | command displays similar information, | |
1920 | in a form that may be easier for parsing.) | |
1f0add28 | 1921 | For each mapping there is a series of lines such as the following: |
37d5e699 | 1922 | .IP |
a08ea57c | 1923 | .in +4n |
37d5e699 | 1924 | .EX |
9bc87ed0 | 1925 | 00400000\-0048a000 r\-xp 00000000 fd:03 960637 /bin/bash |
95fe794d PG |
1926 | Size: 552 kB |
1927 | Rss: 460 kB | |
1928 | Pss: 100 kB | |
1929 | Shared_Clean: 452 kB | |
1930 | Shared_Dirty: 0 kB | |
1931 | Private_Clean: 8 kB | |
1932 | Private_Dirty: 0 kB | |
1933 | Referenced: 460 kB | |
1934 | Anonymous: 0 kB | |
1935 | AnonHugePages: 0 kB | |
4ad958e1 MK |
1936 | ShmemHugePages: 0 kB |
1937 | ShmemPmdMapped: 0 kB | |
95fe794d PG |
1938 | Swap: 0 kB |
1939 | KernelPageSize: 4 kB | |
1940 | MMUPageSize: 4 kB | |
6861f8f0 MK |
1941 | KernelPageSize: 4 kB |
1942 | MMUPageSize: 4 kB | |
95fe794d | 1943 | Locked: 0 kB |
2f057281 | 1944 | ProtectionKey: 0 |
eb848708 | 1945 | VmFlags: rd ex mr mw me dw |
37d5e699 | 1946 | .EE |
a08ea57c | 1947 | .in |
2d3fb75b | 1948 | .IP |
b07b19c4 MK |
1949 | The first of these lines shows the same information as is displayed |
1950 | for the mapping in | |
69119dc7 | 1951 | .IR /proc/[pid]/maps . |
c3d59262 | 1952 | The following lines show the size of the mapping, |
95fe794d | 1953 | the amount of the mapping that is currently resident in RAM ("Rss"), |
a5a3e91b | 1954 | the process's proportional share of this mapping ("Pss"), |
1f0add28 | 1955 | the number of clean and dirty shared pages in the mapping, |
c7ce200d | 1956 | and the number of clean and dirty private pages in the mapping. |
95fe794d | 1957 | "Referenced" indicates the amount of memory currently marked as |
1f0add28 MK |
1958 | referenced or accessed. |
1959 | "Anonymous" shows the amount of memory | |
1960 | that does not belong to any file. | |
1961 | "Swap" shows how much | |
95fe794d | 1962 | would-be-anonymous memory is also used, but out on swap. |
2dad4c59 | 1963 | .IP |
6861f8f0 MK |
1964 | The "KernelPageSize" line (available since Linux 2.6.29) |
1965 | is the page size used by the kernel to back the virtual memory area. | |
1f0add28 MK |
1966 | This matches the size used by the MMU in the majority of cases. |
1967 | However, one counter-example occurs on PPC64 kernels | |
c7169ee5 | 1968 | whereby a kernel using 64 kB as a base page size may still use 4 kB |
1f0add28 | 1969 | pages for the MMU on older processors. |
6861f8f0 MK |
1970 | To distinguish the two attributes, the "MMUPageSize" line |
1971 | (also available since Linux 2.6.29) | |
1972 | reports the page size used by the MMU. | |
2dad4c59 | 1973 | .IP |
95fe794d PG |
1974 | The "Locked" indicates whether the mapping is locked in memory |
1975 | or not. | |
2dad4c59 | 1976 | .IP |
9b780b06 MK |
1977 | The "ProtectionKey" line (available since Linux 4.9, on x86 only) |
1978 | contains the memory protection key (see | |
1979 | .BR pkeys (7)) | |
1980 | associated with the virtual memory area. | |
1981 | This entry is present only if the kernel was built with the | |
1982 | .B CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS | |
9ae9894c | 1983 | configuration option (since Linux 4.6). |
2dad4c59 | 1984 | .IP |
eb848708 MK |
1985 | The "VmFlags" line (available since Linux 3.8) |
1986 | represents the kernel flags associated with the virtual memory area, | |
1987 | encoded using the following two-letter codes: | |
2dad4c59 | 1988 | .IP |
95fe794d | 1989 | rd - readable |
1f0add28 | 1990 | wr - writable |
95fe794d PG |
1991 | ex - executable |
1992 | sh - shared | |
1993 | mr - may read | |
1994 | mw - may write | |
1995 | me - may execute | |
1996 | ms - may share | |
723e333c | 1997 | gd - stack segment grows down |
95fe794d PG |
1998 | pf - pure PFN range |
1999 | dw - disabled write to the mapped file | |
2000 | lo - pages are locked in memory | |
2001 | io - memory mapped I/O area | |
2002 | sr - sequential read advise provided | |
2003 | rr - random read advise provided | |
2004 | dc - do not copy area on fork | |
2005 | de - do not expand area on remapping | |
2006 | ac - area is accountable | |
2007 | nr - swap space is not reserved for the area | |
2008 | ht - area uses huge tlb pages | |
9a766452 | 2009 | sf - perform synchronous page faults (since Linux 4.15) |
efd54c4a | 2010 | nl - non-linear mapping (removed in Linux 4.0) |
95fe794d | 2011 | ar - architecture specific flag |
016dedb3 | 2012 | wf - wipe on fork (since Linux 4.14) |
95fe794d | 2013 | dd - do not include area into core dump |
8485aade | 2014 | sd - soft-dirty flag (since Linux 3.13) |
95fe794d PG |
2015 | mm - mixed map area |
2016 | hg - huge page advise flag | |
2017 | nh - no-huge page advise flag | |
b5408a0f | 2018 | mg - mergeable advise flag |
bc60704e MK |
2019 | um - userfaultfd missing pages tracking (since Linux 4.3) |
2020 | uw - userfaultfd wprotect pages tracking (since Linux 4.3) | |
2dad4c59 | 2021 | .IP |
e618d945 MK |
2022 | The |
2023 | .IR /proc/[pid]/smaps | |
2024 | file is present only if the | |
2025 | .B CONFIG_PROC_PAGE_MONITOR | |
2026 | kernel configuration option is enabled. | |
b07b19c4 | 2027 | .TP |
67aac6fb MK |
2028 | .IR /proc/[pid]/stack " (since Linux 2.6.29)" |
2029 | .\" 2ec220e27f5040aec1e88901c1b6ea3d135787ad | |
2030 | This file provides a symbolic trace of the function calls in this | |
2031 | process's kernel stack. | |
2032 | This file is provided only if the kernel was built with the | |
2033 | .B CONFIG_STACKTRACE | |
2034 | configuration option. | |
2dad4c59 | 2035 | .IP |
4834ae91 MK |
2036 | Permission to access this file is governed by a ptrace access mode |
2037 | .B PTRACE_MODE_ATTACH_FSCREDS | |
2038 | check; see | |
2039 | .BR ptrace (2). | |
67aac6fb | 2040 | .TP |
69119dc7 | 2041 | .I /proc/[pid]/stat |
c13182ef MK |
2042 | Status information about the process. |
2043 | This is used by | |
2044 | .BR ps (1). | |
082bf5b8 MK |
2045 | It is defined in the kernel source file |
2046 | .IR fs/proc/array.c "." | |
2dad4c59 | 2047 | .IP |
fea681da MK |
2048 | The fields, in order, with their proper |
2049 | .BR scanf (3) | |
b02b4b74 MK |
2050 | format specifiers, are listed below. |
2051 | Whether or not certain of these fields display valid information is governed by | |
2052 | a ptrace access mode | |
2c916a1d | 2053 | .BR PTRACE_MODE_READ_FSCREDS " | " PTRACE_MODE_NOAUDIT |
b02b4b74 MK |
2054 | check (refer to |
2055 | .BR ptrace (2)). | |
2056 | If the check denies access, then the field value is displayed as 0. | |
2057 | The affected fields are indicated with the marking [PT]. | |
fea681da | 2058 | .RS |
14948ad6 | 2059 | .TP |
62e4a418 MK |
2060 | (1) \fIpid\fP \ %d |
2061 | .br | |
2062 | The process ID. | |
fea681da | 2063 | .TP |
62e4a418 MK |
2064 | (2) \fIcomm\fP \ %s |
2065 | The filename of the executable, in parentheses. | |
b260aaec AD |
2066 | Strings longer than |
2067 | .B TASK_COMM_LEN | |
2068 | (16) characters (including the terminating null byte) are silently truncated. | |
c13182ef | 2069 | This is visible whether or not the executable is swapped out. |
fea681da | 2070 | .TP |
62e4a418 | 2071 | (3) \fIstate\fP \ %c |
31293f37 MK |
2072 | One of the following characters, indicating process state: |
2073 | .RS | |
2074 | .IP R 3 | |
2075 | Running | |
2076 | .IP S | |
2077 | Sleeping in an interruptible wait | |
2078 | .IP D | |
2079 | Waiting in uninterruptible | |
2080 | disk sleep | |
2081 | .IP Z | |
2082 | Zombie | |
2083 | .IP T | |
2084 | Stopped (on a signal) or (before Linux 2.6.33) trace stopped | |
2085 | .IP t | |
2086 | .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 | |
2087 | Tracing stop (Linux 2.6.33 onward) | |
2088 | .IP W | |
2089 | Paging (only before Linux 2.6.0) | |
2090 | .IP X | |
ef4f4031 | 2091 | Dead (from Linux 2.6.0 onward) |
31293f37 MK |
2092 | .IP x |
2093 | .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 | |
2094 | Dead (Linux 2.6.33 to | |
2095 | .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 | |
2096 | 3.13 only) | |
2097 | .IP K | |
2098 | .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 | |
2099 | Wakekill (Linux 2.6.33 to | |
2100 | .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 | |
2101 | 3.13 only) | |
2102 | .IP W | |
2103 | .\" commit 44d90df6b757c59651ddd55f1a84f28132b50d29 | |
2104 | Waking (Linux 2.6.33 to | |
2105 | .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 | |
2106 | 3.13 only) | |
2107 | .IP P | |
2108 | .\" commit f2530dc71cf0822f90bb63ea4600caaef33a66bb | |
2109 | Parked (Linux 3.9 to | |
2110 | .\" commit 74e37200de8e9c4e09b70c21c3f13c2071e77457 | |
2111 | 3.13 only) | |
2112 | .RE | |
fea681da | 2113 | .TP |
62e4a418 | 2114 | (4) \fIppid\fP \ %d |
e0fdc57c | 2115 | The PID of the parent of this process. |
fea681da | 2116 | .TP |
62e4a418 MK |
2117 | (5) \fIpgrp\fP \ %d |
2118 | The process group ID of the process. | |
fea681da | 2119 | .TP |
62e4a418 MK |
2120 | (6) \fIsession\fP \ %d |
2121 | The session ID of the process. | |
fea681da | 2122 | .TP |
62e4a418 MK |
2123 | (7) \fItty_nr\fP \ %d |
2124 | The controlling terminal of the process. | |
59a40ed7 MK |
2125 | (The minor device number is contained in the combination of bits |
2126 | 31 to 20 and 7 to 0; | |
b97deb97 | 2127 | the major device number is in bits 15 to 8.) |
fea681da | 2128 | .TP |
62e4a418 | 2129 | (8) \fItpgid\fP \ %d |
fea681da | 2130 | .\" This field and following, up to and including wchan added 0.99.1 |
62e4a418 | 2131 | The ID of the foreground process group of the controlling |
59a40ed7 | 2132 | terminal of the process. |
fea681da | 2133 | .TP |
62e4a418 MK |
2134 | (9) \fIflags\fP \ %u |
2135 | The kernel flags word of the process. | |
c13182ef | 2136 | For bit meanings, |
66a9882e | 2137 | see the PF_* defines in the Linux kernel source file |
00702acc | 2138 | .IR include/linux/sched.h . |
fea681da | 2139 | Details depend on the kernel version. |
2dad4c59 | 2140 | .IP |
62e4a418 | 2141 | The format for this field was %lu before Linux 2.6. |
fea681da | 2142 | .TP |
ee566744 | 2143 | (10) \fIminflt\fP \ %lu |
62e4a418 | 2144 | The number of minor faults the process has made which have not |
fea681da MK |
2145 | required loading a memory page from disk. |
2146 | .TP | |
62e4a418 MK |
2147 | (11) \fIcminflt\fP \ %lu |
2148 | The number of minor faults that the process's | |
fea681da MK |
2149 | waited-for children have made. |
2150 | .TP | |
62e4a418 MK |
2151 | (12) \fImajflt\fP \ %lu |
2152 | The number of major faults the process has made which have | |
fea681da MK |
2153 | required loading a memory page from disk. |
2154 | .TP | |
62e4a418 MK |
2155 | (13) \fIcmajflt\fP \ %lu |
2156 | The number of major faults that the process's | |
fea681da MK |
2157 | waited-for children have made. |
2158 | .TP | |
62e4a418 MK |
2159 | (14) \fIutime\fP \ %lu |
2160 | Amount of time that this process has been scheduled in user mode, | |
7a017e24 | 2161 | measured in clock ticks (divide by |
67914165 | 2162 | .IR sysconf(_SC_CLK_TCK) ). |
a1c9dc59 MK |
2163 | This includes guest time, \fIguest_time\fP |
2164 | (time spent running a virtual CPU, see below), | |
2165 | so that applications that are not aware of the guest time field | |
2166 | do not lose that time from their calculations. | |
fea681da | 2167 | .TP |
62e4a418 MK |
2168 | (15) \fIstime\fP \ %lu |
2169 | Amount of time that this process has been scheduled in kernel mode, | |
7a017e24 | 2170 | measured in clock ticks (divide by |
67914165 | 2171 | .IR sysconf(_SC_CLK_TCK) ). |
fea681da | 2172 | .TP |
62e4a418 MK |
2173 | (16) \fIcutime\fP \ %ld |
2174 | Amount of time that this process's | |
7a017e24 MK |
2175 | waited-for children have been scheduled in user mode, |
2176 | measured in clock ticks (divide by | |
67914165 | 2177 | .IR sysconf(_SC_CLK_TCK) ). |
c13182ef | 2178 | (See also |
fea681da | 2179 | .BR times (2).) |
a1c9dc59 MK |
2180 | This includes guest time, \fIcguest_time\fP |
2181 | (time spent running a virtual CPU, see below). | |
fea681da | 2182 | .TP |
62e4a418 MK |
2183 | (17) \fIcstime\fP \ %ld |
2184 | Amount of time that this process's | |
7a017e24 MK |
2185 | waited-for children have been scheduled in kernel mode, |
2186 | measured in clock ticks (divide by | |
67914165 | 2187 | .IR sysconf(_SC_CLK_TCK) ). |
fea681da | 2188 | .TP |
62e4a418 MK |
2189 | (18) \fIpriority\fP \ %ld |
2190 | (Explanation for Linux 2.6) | |
59a40ed7 MK |
2191 | For processes running a real-time scheduling policy |
2192 | .RI ( policy | |
2193 | below; see | |
2194 | .BR sched_setscheduler (2)), | |
2195 | this is the negated scheduling priority, minus one; | |
2196 | that is, a number in the range \-2 to \-100, | |
2197 | corresponding to real-time priorities 1 to 99. | |
2198 | For processes running under a non-real-time scheduling policy, | |
2199 | this is the raw nice value | |
2200 | .RB ( setpriority (2)) | |
2201 | as represented in the kernel. | |
2202 | The kernel stores nice values as numbers | |
2203 | in the range 0 (high) to 39 (low), | |
2204 | corresponding to the user-visible nice range of \-20 to 19. | |
2dad4c59 | 2205 | .IP |
59a40ed7 MK |
2206 | Before Linux 2.6, this was a scaled value based on |
2207 | the scheduler weighting given to this process. | |
2208 | .\" And back in kernel 1.2 days things were different again. | |
fea681da | 2209 | .TP |
62e4a418 MK |
2210 | (19) \fInice\fP \ %ld |
2211 | The nice value (see | |
59a40ed7 MK |
2212 | .BR setpriority (2)), |
2213 | a value in the range 19 (low priority) to \-20 (high priority). | |
2214 | .\" Back in kernel 1.2 days things were different. | |
fea681da MK |
2215 | .\" .TP |
2216 | .\" \fIcounter\fP %ld | |
2217 | .\" The current maximum size in jiffies of the process's next timeslice, | |
2218 | .\" or what is currently left of its current timeslice, if it is the | |
2219 | .\" currently running process. | |
2220 | .\" .TP | |
2221 | .\" \fItimeout\fP %u | |
2222 | .\" The time in jiffies of the process's next timeout. | |
0e94f77b | 2223 | .\" timeout was removed sometime around 2.1/2.2 |
aa610245 | 2224 | .TP |
62e4a418 MK |
2225 | (20) \fInum_threads\fP \ %ld |
2226 | Number of threads in this process (since Linux 2.6). | |
bb83d1b9 | 2227 | Before kernel 2.6, this field was hard coded to 0 as a placeholder |
0e94f77b | 2228 | for an earlier removed field. |
fea681da | 2229 | .TP |
62e4a418 MK |
2230 | (21) \fIitrealvalue\fP \ %ld |
2231 | The time in jiffies before the next | |
8bd58774 MK |
2232 | .B SIGALRM |
2233 | is sent to the process due to an interval timer. | |
0e94f77b MK |
2234 | Since kernel 2.6.17, this field is no longer maintained, |
2235 | and is hard coded as 0. | |
fea681da | 2236 | .TP |
62e4a418 MK |
2237 | (22) \fIstarttime\fP \ %llu |
2238 | The time the process started after system boot. | |
055024ed MK |
2239 | In kernels before Linux 2.6, this value was expressed in jiffies. |
2240 | Since Linux 2.6, the value is expressed in clock ticks (divide by | |
2241 | .IR sysconf(_SC_CLK_TCK) ). | |
2dad4c59 | 2242 | .IP |
62e4a418 | 2243 | The format for this field was %lu before Linux 2.6. |
fea681da | 2244 | .TP |
62e4a418 MK |
2245 | (23) \fIvsize\fP \ %lu |
2246 | Virtual memory size in bytes. | |
fea681da | 2247 | .TP |
62e4a418 MK |
2248 | (24) \fIrss\fP \ %ld |
2249 | Resident Set Size: number of pages the process has in real memory. | |
c13182ef | 2250 | This is just the pages which |
5fab2e7c | 2251 | count toward text, data, or stack space. |
c13182ef | 2252 | This does not include pages |
fea681da | 2253 | which have not been demand-loaded in, or which are swapped out. |
20e43cd6 JH |
2254 | This value is inaccurate; see |
2255 | .I /proc/[pid]/statm | |
2256 | below. | |
fea681da | 2257 | .TP |
62e4a418 MK |
2258 | (25) \fIrsslim\fP \ %lu |
2259 | Current soft limit in bytes on the rss of the process; | |
59a40ed7 MK |
2260 | see the description of |
2261 | .B RLIMIT_RSS | |
2262 | in | |
2b5407af | 2263 | .BR getrlimit (2). |
fea681da | 2264 | .TP |
b02b4b74 | 2265 | (26) \fIstartcode\fP \ %lu \ [PT] |
62e4a418 | 2266 | The address above which program text can run. |
fea681da | 2267 | .TP |
b02b4b74 | 2268 | (27) \fIendcode\fP \ %lu \ [PT] |
62e4a418 | 2269 | The address below which program text can run. |
fea681da | 2270 | .TP |
b02b4b74 | 2271 | (28) \fIstartstack\fP \ %lu \ [PT] |
62e4a418 | 2272 | The address of the start (i.e., bottom) of the stack. |
fea681da | 2273 | .TP |
b02b4b74 | 2274 | (29) \fIkstkesp\fP \ %lu \ [PT] |
62e4a418 | 2275 | The current value of ESP (stack pointer), as found in the |
fea681da MK |
2276 | kernel stack page for the process. |
2277 | .TP | |
b02b4b74 | 2278 | (30) \fIkstkeip\fP \ %lu \ [PT] |
62e4a418 | 2279 | The current EIP (instruction pointer). |
fea681da | 2280 | .TP |
62e4a418 MK |
2281 | (31) \fIsignal\fP \ %lu |
2282 | The bitmap of pending signals, displayed as a decimal number. | |
59a40ed7 | 2283 | Obsolete, because it does not provide information on real-time signals; use |
69119dc7 | 2284 | .I /proc/[pid]/status |
59a40ed7 | 2285 | instead. |
fea681da | 2286 | .TP |
62e4a418 MK |
2287 | (32) \fIblocked\fP \ %lu |
2288 | The bitmap of blocked signals, displayed as a decimal number. | |
59a40ed7 | 2289 | Obsolete, because it does not provide information on real-time signals; use |
69119dc7 | 2290 | .I /proc/[pid]/status |
59a40ed7 | 2291 | instead. |
fea681da | 2292 | .TP |
62e4a418 MK |
2293 | (33) \fIsigignore\fP \ %lu |
2294 | The bitmap of ignored signals, displayed as a decimal number. | |
59a40ed7 | 2295 | Obsolete, because it does not provide information on real-time signals; use |
69119dc7 | 2296 | .I /proc/[pid]/status |
59a40ed7 | 2297 | instead. |
fea681da | 2298 | .TP |
62e4a418 MK |
2299 | (34) \fIsigcatch\fP \ %lu |
2300 | The bitmap of caught signals, displayed as a decimal number. | |
59a40ed7 | 2301 | Obsolete, because it does not provide information on real-time signals; use |
69119dc7 | 2302 | .I /proc/[pid]/status |
59a40ed7 | 2303 | instead. |
fea681da | 2304 | .TP |
b02b4b74 | 2305 | (35) \fIwchan\fP \ %lu \ [PT] |
62e4a418 | 2306 | This is the "channel" in which the process is waiting. |
2054f761 MK |
2307 | It is the address of a location in the kernel where the process is sleeping. |
2308 | The corresponding symbolic name can be found in | |
2309 | .IR /proc/[pid]/wchan . | |
fea681da | 2310 | .TP |
62e4a418 | 2311 | (36) \fInswap\fP \ %lu |
0633f951 | 2312 | .\" nswap was added in 2.0 |
4d9b6984 | 2313 | Number of pages swapped (not maintained). |
fea681da | 2314 | .TP |
62e4a418 | 2315 | (37) \fIcnswap\fP \ %lu |
0633f951 | 2316 | .\" cnswap was added in 2.0 |
4d9b6984 | 2317 | Cumulative \fInswap\fP for child processes (not maintained). |
fea681da | 2318 | .TP |
62e4a418 MK |
2319 | (38) \fIexit_signal\fP \ %d \ (since Linux 2.1.22) |
2320 | Signal to be sent to parent when we die. | |
fea681da | 2321 | .TP |
62e4a418 MK |
2322 | (39) \fIprocessor\fP \ %d \ (since Linux 2.2.8) |
2323 | CPU number last executed on. | |
568105c6 | 2324 | .TP |
62e4a418 MK |
2325 | (40) \fIrt_priority\fP \ %u \ (since Linux 2.5.19) |
2326 | Real-time scheduling priority, a number in the range 1 to 99 for | |
59a40ed7 MK |
2327 | processes scheduled under a real-time policy, |
2328 | or 0, for non-real-time processes (see | |
568105c6 MK |
2329 | .BR sched_setscheduler (2)). |
2330 | .TP | |
62e4a418 MK |
2331 | (41) \fIpolicy\fP \ %u \ (since Linux 2.5.19) |
2332 | Scheduling policy (see | |
568105c6 | 2333 | .BR sched_setscheduler (2)). |
cd60dedd | 2334 | Decode using the SCHED_* constants in |
59a40ed7 | 2335 | .IR linux/sched.h . |
2dad4c59 | 2336 | .IP |
62e4a418 | 2337 | The format for this field was %lu before Linux 2.6.22. |
167450d6 | 2338 | .TP |
62e4a418 MK |
2339 | (42) \fIdelayacct_blkio_ticks\fP \ %llu \ (since Linux 2.6.18) |
2340 | Aggregated block I/O delays, measured in clock ticks (centiseconds). | |
14c06953 | 2341 | .TP |
62e4a418 MK |
2342 | (43) \fIguest_time\fP \ %lu \ (since Linux 2.6.24) |
2343 | Guest time of the process (time spent running a virtual CPU | |
7a017e24 | 2344 | for a guest operating system), measured in clock ticks (divide by |
67914165 | 2345 | .IR sysconf(_SC_CLK_TCK) ). |
14c06953 | 2346 | .TP |
62e4a418 MK |
2347 | (44) \fIcguest_time\fP \ %ld \ (since Linux 2.6.24) |
2348 | Guest time of the process's children, measured in clock ticks (divide by | |
67914165 | 2349 | .IR sysconf(_SC_CLK_TCK) ). |
fea681da | 2350 | .TP |
b02b4b74 | 2351 | (45) \fIstart_data\fP \ %lu \ (since Linux 3.3) \ [PT] |
0be30a54 | 2352 | .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
62e4a418 | 2353 | Address above which program initialized and |
426bc8d7 | 2354 | uninitialized (BSS) data are placed. |
12449ae3 | 2355 | .TP |
b02b4b74 | 2356 | (46) \fIend_data\fP \ %lu \ (since Linux 3.3) \ [PT] |
0be30a54 | 2357 | .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
62e4a418 | 2358 | Address below which program initialized and |
426bc8d7 | 2359 | uninitialized (BSS) data are placed. |
12449ae3 | 2360 | .TP |
b02b4b74 | 2361 | (47) \fIstart_brk\fP \ %lu \ (since Linux 3.3) \ [PT] |
0be30a54 | 2362 | .\" commit b3f7f573a20081910e34e99cbc91831f4f02f1ff |
62e4a418 | 2363 | Address above which program heap can be expanded with |
426bc8d7 | 2364 | .BR brk (2). |
12449ae3 | 2365 | .TP |
b02b4b74 | 2366 | (48) \fIarg_start\fP \ %lu \ (since Linux 3.5) \ [PT] |
0be30a54 | 2367 | .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
62e4a418 | 2368 | Address above which program command-line arguments |
426bc8d7 MK |
2369 | .RI ( argv ) |
2370 | are placed. | |
12449ae3 | 2371 | .TP |
b02b4b74 | 2372 | (49) \fIarg_end\fP \ %lu \ (since Linux 3.5) \ [PT] |
0be30a54 | 2373 | .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
62e4a418 | 2374 | Address below program command-line arguments |
426bc8d7 MK |
2375 | .RI ( argv ) |
2376 | are placed. | |
12449ae3 | 2377 | .TP |
b02b4b74 | 2378 | (50) \fIenv_start\fP \ %lu \ (since Linux 3.5) \ [PT] |
0be30a54 | 2379 | .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
62e4a418 | 2380 | Address above which program environment is placed. |
12449ae3 | 2381 | .TP |
b02b4b74 | 2382 | (51) \fIenv_end\fP \ %lu \ (since Linux 3.5) \ [PT] |
0be30a54 | 2383 | .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
62e4a418 | 2384 | Address below which program environment is placed. |
12449ae3 | 2385 | .TP |
b02b4b74 | 2386 | (52) \fIexit_code\fP \ %d \ (since Linux 3.5) \ [PT] |
0be30a54 | 2387 | .\" commit 5b172087f99189416d5f47fd7ab5e6fb762a9ba3 |
62e4a418 | 2388 | The thread's exit status in the form reported by |
426bc8d7 | 2389 | .BR waitpid (2). |
12449ae3 | 2390 | .RE |
2391 | .TP | |
69119dc7 | 2392 | .I /proc/[pid]/statm |
59a40ed7 | 2393 | Provides information about memory usage, measured in pages. |
c13182ef | 2394 | The columns are: |
37d5e699 | 2395 | .IP |
a08ea57c | 2396 | .in +4n |
37d5e699 | 2397 | .EX |
cb42fb56 | 2398 | size (1) total program size |
69119dc7 | 2399 | (same as VmSize in \fI/proc/[pid]/status\fP) |
cb42fb56 | 2400 | resident (2) resident set size |
20e43cd6 | 2401 | (inaccurate; same as VmRSS in \fI/proc/[pid]/status\fP) |
14948ad6 MK |
2402 | shared (3) number of resident shared pages |
2403 | (i.e., backed by a file) | |
20e43cd6 JH |
2404 | (inaccurate; same as RssFile+RssShmem in |
2405 | \fI/proc/[pid]/status\fP) | |
cb42fb56 | 2406 | text (4) text (code) |
59a40ed7 | 2407 | .\" (not including libs; broken, includes data segment) |
d133b9b3 | 2408 | lib (5) library (unused since Linux 2.6; always 0) |
cb42fb56 | 2409 | data (6) data + stack |
59a40ed7 | 2410 | .\" (including libs; broken, includes library text) |
d133b9b3 | 2411 | dt (7) dirty pages (unused since Linux 2.6; always 0) |
37d5e699 | 2412 | .EE |
a08ea57c | 2413 | .in |
20e43cd6 JH |
2414 | .IP |
2415 | .\" See SPLIT_RSS_COUNTING in the kernel. | |
2416 | .\" Inaccuracy is bounded by TASK_RSS_EVENTS_THRESH. | |
2417 | Some of these values are inaccurate because | |
2418 | of a kernel-internal scalability optimization. | |
2419 | If accurate values are required, use | |
2420 | .I /proc/[pid]/smaps | |
2421 | or | |
2422 | .I /proc/[pid]/smaps_rollup | |
2423 | instead, which are much slower but provide accurate, detailed information. | |
fea681da | 2424 | .TP |
69119dc7 | 2425 | .I /proc/[pid]/status |
fea681da | 2426 | Provides much of the information in |
69119dc7 | 2427 | .I /proc/[pid]/stat |
fea681da | 2428 | and |
69119dc7 | 2429 | .I /proc/[pid]/statm |
fea681da | 2430 | in a format that's easier for humans to parse. |
16b5f7ba | 2431 | Here's an example: |
37d5e699 | 2432 | .IP |
16b5f7ba | 2433 | .in +4n |
37d5e699 | 2434 | .EX |
b43a3b30 | 2435 | .RB "$" " cat /proc/$$/status" |
16b5f7ba | 2436 | Name: bash |
a79343e9 | 2437 | Umask: 0022 |
16b5f7ba | 2438 | State: S (sleeping) |
aac0b30f | 2439 | Tgid: 17248 |
2d2dfb69 | 2440 | Ngid: 0 |
aac0b30f MK |
2441 | Pid: 17248 |
2442 | PPid: 17200 | |
16b5f7ba MK |
2443 | TracerPid: 0 |
2444 | Uid: 1000 1000 1000 1000 | |
2445 | Gid: 100 100 100 100 | |
2446 | FDSize: 256 | |
2447 | Groups: 16 33 100 | |
aac0b30f MK |
2448 | NStgid: 17248 |
2449 | NSpid: 17248 | |
2450 | NSpgid: 17248 | |
2451 | NSsid: 17200 | |
06b7cee0 MK |
2452 | VmPeak: 131168 kB |
2453 | VmSize: 131168 kB | |
2454 | VmLck: 0 kB | |
2455 | VmPin: 0 kB | |
2456 | VmHWM: 13484 kB | |
2457 | VmRSS: 13484 kB | |
e546617e MK |
2458 | RssAnon: 10264 kB |
2459 | RssFile: 3220 kB | |
2460 | RssShmem: 0 kB | |
06b7cee0 MK |
2461 | VmData: 10332 kB |
2462 | VmStk: 136 kB | |
2463 | VmExe: 992 kB | |
2464 | VmLib: 2104 kB | |
2465 | VmPTE: 76 kB | |
2466 | VmPMD: 12 kB | |
2467 | VmSwap: 0 kB | |
4084d612 | 2468 | HugetlbPages: 0 kB # 4.4 |
4641c596 | 2469 | CoreDumping: 0 # 4.15 |
16b5f7ba MK |
2470 | Threads: 1 |
2471 | SigQ: 0/3067 | |
2472 | SigPnd: 0000000000000000 | |
2473 | ShdPnd: 0000000000000000 | |
2474 | SigBlk: 0000000000010000 | |
2475 | SigIgn: 0000000000384004 | |
2476 | SigCgt: 000000004b813efb | |
2477 | CapInh: 0000000000000000 | |
2478 | CapPrm: 0000000000000000 | |
2479 | CapEff: 0000000000000000 | |
2480 | CapBnd: ffffffffffffffff | |
6112ea97 | 2481 | CapAmb: 0000000000000000 |
6c0ed873 | 2482 | NoNewPrivs: 0 |
039b6546 | 2483 | Seccomp: 0 |
bf8fc275 | 2484 | Speculation_Store_Bypass: vulnerable |
16b5f7ba MK |
2485 | Cpus_allowed: 00000001 |
2486 | Cpus_allowed_list: 0 | |
2487 | Mems_allowed: 1 | |
2488 | Mems_allowed_list: 0 | |
2489 | voluntary_ctxt_switches: 150 | |
2490 | nonvoluntary_ctxt_switches: 545 | |
37d5e699 | 2491 | .EE |
16b5f7ba MK |
2492 | .in |
2493 | .IP | |
2494 | The fields are as follows: | |
2495 | .RS | |
bd13ace0 MK |
2496 | .TP |
2497 | .IR Name | |
16b5f7ba | 2498 | Command run by this process. |
b260aaec AD |
2499 | Strings longer than |
2500 | .B TASK_COMM_LEN | |
2501 | (16) characters (including the terminating null byte) are silently truncated. | |
bd13ace0 MK |
2502 | .TP |
2503 | .IR Umask | |
53473996 MK |
2504 | Process umask, expressed in octal with a leading zero; see |
2505 | .BR umask (2). | |
a79343e9 | 2506 | (Since Linux 4.7.) |
bd13ace0 MK |
2507 | .TP |
2508 | .IR State | |
4175f999 MK |
2509 | Current state of the process. |
2510 | One of | |
16b5f7ba MK |
2511 | "R (running)", |
2512 | "S (sleeping)", | |
2513 | "D (disk sleep)", | |
2514 | "T (stopped)", | |
ea893369 | 2515 | "t (tracing stop)", |
16b5f7ba MK |
2516 | "Z (zombie)", |
2517 | or | |
2518 | "X (dead)". | |
bd13ace0 MK |
2519 | .TP |
2520 | .IR Tgid | |
16b5f7ba | 2521 | Thread group ID (i.e., Process ID). |
bd13ace0 MK |
2522 | .TP |
2523 | .IR Ngid | |
2d2dfb69 | 2524 | NUMA group ID (0 if none; since Linux 3.13). |
bd13ace0 MK |
2525 | .TP |
2526 | .IR Pid | |
16b5f7ba MK |
2527 | Thread ID (see |
2528 | .BR gettid (2)). | |
bd13ace0 MK |
2529 | .TP |
2530 | .IR PPid | |
a1bc91d5 | 2531 | PID of parent process. |
bd13ace0 MK |
2532 | .TP |
2533 | .IR TracerPid | |
16b5f7ba | 2534 | PID of process tracing this process (0 if not being traced). |
bd13ace0 MK |
2535 | .TP |
2536 | .IR Uid ", " Gid | |
9ee4a2b6 | 2537 | Real, effective, saved set, and filesystem UIDs (GIDs). |
bd13ace0 MK |
2538 | .TP |
2539 | .IR FDSize | |
16b5f7ba | 2540 | Number of file descriptor slots currently allocated. |
bd13ace0 MK |
2541 | .TP |
2542 | .IR Groups | |
16b5f7ba | 2543 | Supplementary group list. |
bd13ace0 MK |
2544 | .TP |
2545 | .IR NStgid | |
aac0b30f MK |
2546 | Thread group ID (i.e., PID) in each of the PID namespaces of which |
2547 | .I [pid] | |
2548 | is a member. | |
2549 | The leftmost entry shows the value with respect to the PID namespace | |
0aae4092 KF |
2550 | of the process that mounted this procfs (or the root namespace |
2551 | if mounted by the kernel), | |
aac0b30f MK |
2552 | followed by the value in successively nested inner namespaces. |
2553 | .\" commit e4bc33245124db69b74a6d853ac76c2976f472d5 | |
2554 | (Since Linux 4.1.) | |
bd13ace0 MK |
2555 | .TP |
2556 | .IR NSpid | |
aac0b30f MK |
2557 | Thread ID in each of the PID namespaces of which |
2558 | .I [pid] | |
2559 | is a member. | |
2560 | The fields are ordered as for | |
2561 | .IR NStgid . | |
2562 | (Since Linux 4.1.) | |
bd13ace0 MK |
2563 | .TP |
2564 | .IR NSpgid | |
aac0b30f MK |
2565 | Process group ID in each of the PID namespaces of which |
2566 | .I [pid] | |
2567 | is a member. | |
2568 | The fields are ordered as for | |
2569 | .IR NStgid . | |
2570 | (Since Linux 4.1.) | |
bd13ace0 MK |
2571 | .TP |
2572 | .IR NSsid | |
aac0b30f MK |
2573 | descendant namespace session ID hierarchy |
2574 | Session ID in each of the PID namespaces of which | |
2575 | .I [pid] | |
2576 | is a member. | |
2577 | The fields are ordered as for | |
2578 | .IR NStgid . | |
2579 | (Since Linux 4.1.) | |
bd13ace0 MK |
2580 | .TP |
2581 | .IR VmPeak | |
16b5f7ba | 2582 | Peak virtual memory size. |
bd13ace0 MK |
2583 | .TP |
2584 | .IR VmSize | |
16b5f7ba | 2585 | Virtual memory size. |
bd13ace0 MK |
2586 | .TP |
2587 | .IR VmLck | |
fde39195 | 2588 | Locked memory size (see |
f8bfb68e | 2589 | .BR mlock (2)). |
bd13ace0 MK |
2590 | .TP |
2591 | .IR VmPin | |
15789039 TY |
2592 | Pinned memory size |
2593 | .\" commit bc3e53f682d93df677dbd5006a404722b3adfe18 | |
2594 | (since Linux 3.2). | |
2595 | These are pages that can't be moved because something needs to | |
2596 | directly access physical memory. | |
bd13ace0 MK |
2597 | .TP |
2598 | .IR VmHWM | |
16b5f7ba | 2599 | Peak resident set size ("high water mark"). |
20e43cd6 JH |
2600 | This value is inaccurate; see |
2601 | .I /proc/[pid]/statm | |
2602 | above. | |
bd13ace0 MK |
2603 | .TP |
2604 | .IR VmRSS | |
16b5f7ba | 2605 | Resident set size. |
e546617e MK |
2606 | Note that the value here is the sum of |
2607 | .IR RssAnon , | |
2608 | .IR RssFile , | |
2609 | and | |
2610 | .IR RssShmem . | |
20e43cd6 JH |
2611 | This value is inaccurate; see |
2612 | .I /proc/[pid]/statm | |
2613 | above. | |
bd13ace0 MK |
2614 | .TP |
2615 | .IR RssAnon | |
e546617e MK |
2616 | Size of resident anonymous memory. |
2617 | .\" commit bf9683d6990589390b5178dafe8fd06808869293 | |
2618 | (since Linux 4.5). | |
20e43cd6 JH |
2619 | This value is inaccurate; see |
2620 | .I /proc/[pid]/statm | |
2621 | above. | |
bd13ace0 MK |
2622 | .TP |
2623 | .IR RssFile | |
e546617e MK |
2624 | Size of resident file mappings. |
2625 | .\" commit bf9683d6990589390b5178dafe8fd06808869293 | |
2626 | (since Linux 4.5). | |
20e43cd6 JH |
2627 | This value is inaccurate; see |
2628 | .I /proc/[pid]/statm | |
2629 | above. | |
bd13ace0 MK |
2630 | .TP |
2631 | .IR RssShmem | |
78230722 | 2632 | Size of resident shared memory (includes System V shared memory, |
4e07c70f MK |
2633 | mappings from |
2634 | .BR tmpfs (5), | |
2635 | and shared anonymous mappings). | |
e546617e MK |
2636 | .\" commit bf9683d6990589390b5178dafe8fd06808869293 |
2637 | (since Linux 4.5). | |
bd13ace0 MK |
2638 | .TP |
2639 | .IR VmData ", " VmStk ", " VmExe | |
16b5f7ba | 2640 | Size of data, stack, and text segments. |
20e43cd6 JH |
2641 | This value is inaccurate; see |
2642 | .I /proc/[pid]/statm | |
2643 | above. | |
bd13ace0 MK |
2644 | .TP |
2645 | .IR VmLib | |
16b5f7ba | 2646 | Shared library code size. |
bd13ace0 MK |
2647 | .TP |
2648 | .IR VmPTE | |
16b5f7ba | 2649 | Page table entries size (since Linux 2.6.10). |
bd13ace0 MK |
2650 | .TP |
2651 | .IR VmPMD | |
e28af9cd | 2652 | .\" commit dc6c9a35b66b520cf67e05d8ca60ebecad3b0479 |
fcfac78d | 2653 | Size of second-level page tables (added in Linux 4.0; removed in Linux 4.15). |
bd13ace0 MK |
2654 | .TP |
2655 | .IR VmSwap | |
1ddc1665 | 2656 | .\" commit b084d4353ff99d824d3bc5a5c2c22c70b1fba722 |
fce21149 MK |
2657 | Swapped-out virtual memory size by anonymous private pages; |
2658 | shmem swap usage is not included (since Linux 2.6.34). | |
20e43cd6 JH |
2659 | This value is inaccurate; see |
2660 | .I /proc/[pid]/statm | |
2661 | above. | |
bd13ace0 MK |
2662 | .TP |
2663 | .IR HugetlbPages | |
422425ff | 2664 | Size of hugetlb memory portions |
4084d612 MK |
2665 | .\" commit 5d317b2b6536592a9b51fe65faed43d65ca9158e |
2666 | (since Linux 4.4). | |
bd13ace0 MK |
2667 | .TP |
2668 | .IR CoreDumping | |
4641c596 MK |
2669 | Contains the value 1 if the process is currently dumping core, |
2670 | and 0 if it is not | |
2671 | .\" commit c643401218be0f4ab3522e0c0a63016596d6e9ca | |
2672 | (since Linux 4.15). | |
2673 | This information can be used by a monitoring process to avoid killing | |
2674 | a process that is currently dumping core, | |
2675 | which could result in a corrupted core dump file. | |
bd13ace0 MK |
2676 | .TP |
2677 | .IR Threads | |
16b5f7ba | 2678 | Number of threads in process containing this thread. |
bd13ace0 MK |
2679 | .TP |
2680 | .IR SigQ | |
6ee625eb MK |
2681 | This field contains two slash-separated numbers that relate to |
2682 | queued signals for the real user ID of this process. | |
2683 | The first of these is the number of currently queued | |
2684 | signals for this real user ID, and the second is the | |
2685 | resource limit on the number of queued signals for this process | |
2686 | (see the description of | |
2687 | .BR RLIMIT_SIGPENDING | |
2688 | in | |
2689 | .BR getrlimit (2)). | |
bd13ace0 MK |
2690 | .TP |
2691 | .IR SigPnd ", " ShdPnd | |
8bfbac5d | 2692 | Mask (expressed in hexadecimal) |
9b8887eb | 2693 | of signals pending for thread and for process as a whole (see |
16b5f7ba MK |
2694 | .BR pthreads (7) |
2695 | and | |
2696 | .BR signal (7)). | |
bd13ace0 MK |
2697 | .TP |
2698 | .IR SigBlk ", " SigIgn ", " SigCgt | |
8d839a56 | 2699 | Masks (expressed in hexadecimal) |
a4e6603a | 2700 | indicating signals being blocked, ignored, and caught (see |
16b5f7ba | 2701 | .BR signal (7)). |
bd13ace0 MK |
2702 | .TP |
2703 | .IR CapInh ", " CapPrm ", " CapEff | |
8d839a56 | 2704 | Masks (expressed in hexadecimal) |
a4e6603a | 2705 | of capabilities enabled in inheritable, permitted, and effective sets |
16b5f7ba MK |
2706 | (see |
2707 | .BR capabilities (7)). | |
bd13ace0 MK |
2708 | .TP |
2709 | .IR CapBnd | |
a4e6603a | 2710 | Capability bounding set, expressed in hexadecimal |
7e07d950 | 2711 | (since Linux 2.6.26, see |
16b5f7ba | 2712 | .BR capabilities (7)). |
bd13ace0 MK |
2713 | .TP |
2714 | .IR CapAmb | |
a4e6603a | 2715 | Ambient capability set, expressed in hexadecimal |
6112ea97 MK |
2716 | (since Linux 4.3, see |
2717 | .BR capabilities (7)). | |
bd13ace0 MK |
2718 | .TP |
2719 | .IR NoNewPrivs | |
6c0ed873 MK |
2720 | .\" commit af884cd4a5ae62fcf5e321fecf0ec1014730353d |
2721 | Value of the | |
2722 | .I no_new_privs | |
2723 | bit | |
2724 | (since Linux 4.10, see | |
2725 | .BR prctl (2)). | |
bd13ace0 MK |
2726 | .TP |
2727 | .IR Seccomp | |
039b6546 MK |
2728 | .\" commit 2f4b3bf6b2318cfaa177ec5a802f4d8d6afbd816 |
2729 | Seccomp mode of the process | |
2730 | (since Linux 3.8, see | |
2731 | .BR seccomp (2)). | |
2732 | 0 means | |
2733 | .BR SECCOMP_MODE_DISABLED ; | |
2734 | 1 means | |
2735 | .BR SECCOMP_MODE_STRICT ; | |
2736 | 2 means | |
2737 | .BR SECCOMP_MODE_FILTER . | |
2738 | This field is provided only if the kernel was built with the | |
2739 | .BR CONFIG_SECCOMP | |
2740 | kernel configuration option enabled. | |
bd13ace0 MK |
2741 | .TP |
2742 | .IR Speculation_Store_Bypass | |
bf8fc275 NF |
2743 | .\" commit fae1fa0fc6cca8beee3ab8ed71d54f9a78fa3f64 |
2744 | Speculation flaw mitigation state | |
2745 | (since Linux 4.17, see | |
2746 | .BR prctl (2)). | |
bd13ace0 MK |
2747 | .TP |
2748 | .IR Cpus_allowed | |
a4e6603a | 2749 | Hexadecimal mask of CPUs on which this process may run |
16b5f7ba MK |
2750 | (since Linux 2.6.24, see |
2751 | .BR cpuset (7)). | |
bd13ace0 MK |
2752 | .TP |
2753 | .IR Cpus_allowed_list | |
16b5f7ba MK |
2754 | Same as previous, but in "list format" |
2755 | (since Linux 2.6.26, see | |
2756 | .BR cpuset (7)). | |
bd13ace0 MK |
2757 | .TP |
2758 | .IR Mems_allowed | |
16b5f7ba MK |
2759 | Mask of memory nodes allowed to this process |
2760 | (since Linux 2.6.24, see | |
2761 | .BR cpuset (7)). | |
bd13ace0 MK |
2762 | .TP |
2763 | .IR Mems_allowed_list | |
16b5f7ba MK |
2764 | Same as previous, but in "list format" |
2765 | (since Linux 2.6.26, see | |
2766 | .BR cpuset (7)). | |
bd13ace0 MK |
2767 | .TP |
2768 | .IR voluntary_ctxt_switches ", " nonvoluntary_ctxt_switches | |
16b5f7ba MK |
2769 | Number of voluntary and involuntary context switches (since Linux 2.6.23). |
2770 | .RE | |
afb7b014 MK |
2771 | .TP |
2772 | .IR /proc/[pid]/syscall " (since Linux 2.6.27)" | |
2773 | .\" commit ebcb67341fee34061430f3367f2e507e52ee051b | |
2774 | This file exposes the system call number and argument registers for the | |
2775 | system call currently being executed by the process, | |
2776 | followed by the values of the stack pointer and program counter registers. | |
2777 | The values of all six argument registers are exposed, | |
2778 | although most system calls use fewer registers. | |
2dad4c59 | 2779 | .IP |
afb7b014 | 2780 | If the process is blocked, but not in a system call, |
1fb61947 | 2781 | then the file displays \-1 in place of the system call number, |
afb7b014 | 2782 | followed by just the values of the stack pointer and program counter. |
64fcb6e1 | 2783 | If process is not blocked, then the file contains just the string "running". |
2dad4c59 | 2784 | .IP |
afb7b014 MK |
2785 | This file is present only if the kernel was configured with |
2786 | .BR CONFIG_HAVE_ARCH_TRACEHOOK . | |
2dad4c59 | 2787 | .IP |
4834ae91 MK |
2788 | Permission to access this file is governed by a ptrace access mode |
2789 | .B PTRACE_MODE_ATTACH_FSCREDS | |
2790 | check; see | |
2791 | .BR ptrace (2). | |
fea681da | 2792 | .TP |
d6bec36e MK |
2793 | .IR /proc/[pid]/task " (since Linux 2.6.0)" |
2794 | .\" Precisely: Linux 2.6.0-test6 | |
afcaf646 MK |
2795 | This is a directory that contains one subdirectory |
2796 | for each thread in the process. | |
69119dc7 MK |
2797 | The name of each subdirectory is the numerical thread ID |
2798 | .RI ( [tid] ) | |
2799 | of the thread (see | |
afcaf646 | 2800 | .BR gettid (2)). |
eb8567a5 | 2801 | .IP |
afcaf646 MK |
2802 | Within each of these subdirectories, there is a set of |
2803 | files with the same names and contents as under the | |
69119dc7 | 2804 | .I /proc/[pid] |
afcaf646 MK |
2805 | directories. |
2806 | For attributes that are shared by all threads, the contents for | |
2807 | each of the files under the | |
69119dc7 | 2808 | .I task/[tid] |
afcaf646 | 2809 | subdirectories will be the same as in the corresponding |
c13182ef | 2810 | file in the parent |
69119dc7 | 2811 | .I /proc/[pid] |
afcaf646 | 2812 | directory |
c13182ef | 2813 | (e.g., in a multithreaded process, all of the |
69119dc7 | 2814 | .I task/[tid]/cwd |
c13182ef | 2815 | files will have the same value as the |
69119dc7 | 2816 | .I /proc/[pid]/cwd |
c13182ef | 2817 | file in the parent directory, since all of the threads in a process |
afcaf646 MK |
2818 | share a working directory). |
2819 | For attributes that are distinct for each thread, | |
c13182ef | 2820 | the corresponding files under |
69119dc7 | 2821 | .I task/[tid] |
afcaf646 | 2822 | may have different values (e.g., various fields in each of the |
69119dc7 | 2823 | .I task/[tid]/status |
4a40c703 JH |
2824 | files may be different for each thread), |
2825 | .\" in particular: "children" :/ | |
2826 | or they might not exist in | |
2827 | .I /proc/[pid] | |
2828 | at all. | |
eb8567a5 | 2829 | .IP |
afcaf646 MK |
2830 | .\" The following was still true as at kernel 2.6.13 |
2831 | In a multithreaded process, the contents of the | |
69119dc7 | 2832 | .I /proc/[pid]/task |
c13182ef | 2833 | directory are not available if the main thread has already terminated |
afcaf646 MK |
2834 | (typically by calling |
2835 | .BR pthread_exit (3)). | |
4a40c703 JH |
2836 | .TP |
2837 | .IR /proc/[pid]/task/[tid]/children " (since Linux 3.5)" | |
2838 | .\" commit 818411616baf46ceba0cff6f05af3a9b294734f7 | |
2839 | A space-separated list of child tasks of this task. | |
2840 | Each child task is represented by its TID. | |
2dad4c59 | 2841 | .IP |
4a40c703 | 2842 | .\" see comments in get_children_pid() in fs/proc/array.c |
45dd5092 MK |
2843 | This option is intended for use by the checkpoint-restore (CRIU) system, |
2844 | and reliably provides a list of children only if all of the child processes | |
2845 | are stopped or frozen. | |
2846 | It does not work properly if children of the target task exit while | |
4a40c703 | 2847 | the file is being read! |
45dd5092 | 2848 | Exiting children may cause non-exiting children to be omitted from the list. |
4a40c703 | 2849 | This makes this interface even more unreliable than classic PID-based |
45dd5092 MK |
2850 | approaches if the inspected task and its children aren't frozen, |
2851 | and most code should probably not use this interface. | |
2dad4c59 | 2852 | .IP |
7ded2db4 MK |
2853 | Until Linux 4.2, the presence of this file was governed by the |
2854 | .B CONFIG_CHECKPOINT_RESTORE | |
2855 | kernel configuration option. | |
2856 | Since Linux 4.2, | |
2857 | .\" commit 2e13ba54a2682eea24918b87ad3edf70c2cf085b | |
ae34c521 | 2858 | it is governed by the |
7ded2db4 MK |
2859 | .B CONFIG_PROC_CHILDREN |
2860 | option. | |
afcaf646 | 2861 | .TP |
1509ca0e MK |
2862 | .IR /proc/[pid]/timers " (since Linux 3.10)" |
2863 | .\" commit 5ed67f05f66c41e39880a6d61358438a25f9fee5 | |
2864 | .\" commit 48f6a7a511ef8823fdff39afee0320092d43a8a0 | |
2865 | A list of the POSIX timers for this process. | |
93691c1e | 2866 | Each timer is listed with a line that starts with the string "ID:". |
1509ca0e | 2867 | For example: |
2dad4c59 | 2868 | .IP |
1509ca0e | 2869 | .in +4n |
37d5e699 | 2870 | .EX |
1509ca0e MK |
2871 | ID: 1 |
2872 | signal: 60/00007fff86e452a8 | |
2873 | notify: signal/pid.2634 | |
2874 | ClockID: 0 | |
2875 | ID: 0 | |
2876 | signal: 60/00007fff86e452a8 | |
2877 | notify: signal/pid.2634 | |
2878 | ClockID: 1 | |
37d5e699 | 2879 | .EE |
1509ca0e | 2880 | .in |
2dad4c59 | 2881 | .IP |
1509ca0e MK |
2882 | The lines shown for each timer have the following meanings: |
2883 | .RS | |
2884 | .TP | |
2885 | .I ID | |
2886 | The ID for this timer. | |
2887 | This is not the same as the timer ID returned by | |
2888 | .BR timer_create (2); | |
2889 | rather, it is the same kernel-internal ID that is available via the | |
2890 | .I si_timerid | |
2891 | field of the | |
2892 | .IR siginfo_t | |
2893 | structure (see | |
2894 | .BR sigaction (2)). | |
2895 | .TP | |
2896 | .I signal | |
2897 | This is the signal number that this timer uses to deliver notifications | |
2898 | followed by a slash, and then the | |
7f1ea8fb | 2899 | .I sigev_value |
1509ca0e MK |
2900 | value supplied to the signal handler. |
2901 | Valid only for timers that notify via a signal. | |
2902 | .TP | |
2903 | .I notify | |
2904 | The part before the slash specifies the mechanism | |
2905 | that this timer uses to deliver notifications, | |
2906 | and is one of "thread", "signal", or "none". | |
2907 | Immediately following the slash is either the string "tid" for timers | |
2908 | with | |
2909 | .B SIGEV_THREAD_ID | |
2910 | notification, or "pid" for timers that notify by other mechanisms. | |
dbe6f88b MK |
2911 | Following the "." is the PID of the process |
2912 | (or the kernel thread ID of the thread) that will be delivered | |
1509ca0e MK |
2913 | a signal if the timer delivers notifications via a signal. |
2914 | .TP | |
2915 | .I ClockID | |
2916 | This field identifies the clock that the timer uses for measuring time. | |
2917 | For most clocks, this is a number that matches one of the user-space | |
2918 | .BR CLOCK_* | |
9d54c087 | 2919 | constants exposed via |
1509ca0e MK |
2920 | .IR <time.h> . |
2921 | .B CLOCK_PROCESS_CPUTIME_ID | |
9bc87ed0 | 2922 | timers display with a value of \-6 |
1509ca0e MK |
2923 | in this field. |
2924 | .B CLOCK_THREAD_CPUTIME_ID | |
9bc87ed0 | 2925 | timers display with a value of \-2 |
1509ca0e MK |
2926 | in this field. |
2927 | .RE | |
5734da6d MK |
2928 | .IP |
2929 | This file is available only when the kernel was configured with | |
2930 | .BR CONFIG_CHECKPOINT_RESTORE . | |
1509ca0e | 2931 | .TP |
11f60142 MK |
2932 | .IR /proc/[pid]/timerslack_ns " (since Linux 4.6)" |
2933 | .\" commit da8b44d5a9f8bf26da637b7336508ca534d6b319 | |
2934 | .\" commit 5de23d435e88996b1efe0e2cebe242074ce67c9e | |
2935 | This file exposes the process's "current" timer slack value, | |
2936 | expressed in nanoseconds. | |
2937 | The file is writable, | |
2938 | allowing the process's timer slack value to be changed. | |
2939 | Writing 0 to this file resets the "current" timer slack to the | |
2940 | "default" timer slack value. | |
2941 | For further details, see the discussion of | |
2942 | .BR PR_SET_TIMERSLACK | |
2943 | in | |
2944 | .BR prctl (2). | |
2dad4c59 | 2945 | .IP |
5daae264 MK |
2946 | Initially, |
2947 | permission to access this file was governed by a ptrace access mode | |
a62e0e01 | 2948 | .B PTRACE_MODE_ATTACH_FSCREDS |
5daae264 MK |
2949 | check (see |
2950 | .BR ptrace (2)). | |
2951 | However, this was subsequently deemed too strict a requirement | |
2952 | (and had the side effect that requiring a process to have the | |
2953 | .B CAP_SYS_PTRACE | |
2954 | capability would also allow it to view and change any process's memory). | |
2955 | Therefore, since Linux 4.9, | |
2956 | .\" commit 7abbaf94049914f074306d960b0f968ffe52e59f | |
2957 | only the (weaker) | |
2958 | .B CAP_SYS_NICE | |
2959 | capability is required to access this file. | |
11f60142 | 2960 | .TP |
dd0ccf19 | 2961 | .IR /proc/[pid]/uid_map " (since Linux 3.5)" |
b1aad373 MK |
2962 | See |
2963 | .BR user_namespaces (7). | |
2964 | .TP | |
2965 | .IR /proc/[pid]/wchan " (since Linux 2.6.0)" | |
2966 | The symbolic name corresponding to the location | |
2967 | in the kernel where the process is sleeping. | |
2dad4c59 | 2968 | .IP |
82664739 MK |
2969 | Permission to access this file is governed by a ptrace access mode |
2970 | .B PTRACE_MODE_READ_FSCREDS | |
2971 | check; see | |
2972 | .BR ptrace (2). | |
b1aad373 | 2973 | .TP |
01df7b70 MK |
2974 | .IR /proc/[tid] |
2975 | There is a numerical subdirectory for each running thread | |
2976 | that is not a thread group leader | |
2977 | (i.e., a thread whose thread ID is not the same as its process ID); | |
2978 | the subdirectory is named by the thread ID. | |
2979 | Each one of these subdirectories contains files and subdirectories | |
2980 | exposing information about the thread with the thread ID | |
2981 | .IR tid . | |
2982 | The contents of these directories are the same as the corresponding | |
71190ded | 2983 | .IR /proc/[pid]/task/[tid] |
01df7b70 MK |
2984 | directories. |
2985 | .IP | |
2986 | The | |
2987 | .I /proc/[tid] | |
2988 | subdirectories are | |
2989 | .I not | |
2990 | visible when iterating through | |
2991 | .I /proc | |
2992 | with | |
2993 | .BR getdents (2) | |
2994 | (and thus are | |
2995 | .I not | |
2996 | visible when one uses | |
2997 | .BR ls (1) | |
2998 | to view the contents of | |
2999 | .IR /proc ). | |
37cd58d2 MK |
3000 | However, the pathnames of these directories are visible to |
3001 | (i.e., usable as arguments in) | |
3002 | system calls that operate on pathnames. | |
01df7b70 | 3003 | .TP |
b1aad373 MK |
3004 | .I /proc/apm |
3005 | Advanced power management version and battery information when | |
3006 | .B CONFIG_APM | |
3007 | is defined at kernel compilation time. | |
3008 | .TP | |
3009 | .I /proc/buddyinfo | |
3010 | This file contains information which is used for diagnosing memory | |
3011 | fragmentation issues. | |
3012 | Each line starts with the identification of the node and the name | |
f68d8104 | 3013 | of the zone which together identify a memory region. |
b1aad373 MK |
3014 | This is then |
3015 | followed by the count of available chunks of a certain order in | |
3016 | which these zones are split. | |
3017 | The size in bytes of a certain order is given by the formula: | |
2dad4c59 | 3018 | .IP |
b1aad373 | 3019 | (2^order)\ *\ PAGE_SIZE |
2dad4c59 | 3020 | .IP |
b1aad373 MK |
3021 | The binary buddy allocator algorithm inside the kernel will split |
3022 | one chunk into two chunks of a smaller order (thus with half the | |
3023 | size) or combine two contiguous chunks into one larger chunk of | |
3024 | a higher order (thus with double the size) to satisfy allocation | |
3025 | requests and to counter memory fragmentation. | |
3026 | The order matches the column number, when starting to count at zero. | |
2dad4c59 | 3027 | .IP |
b5b0d21e | 3028 | For example on an x86-64 system: |
e3fb1b6b | 3029 | .RS -12 |
37d5e699 | 3030 | .EX |
b1aad373 MK |
3031 | Node 0, zone DMA 1 1 1 0 2 1 1 0 1 1 3 |
3032 | Node 0, zone DMA32 65 47 4 81 52 28 13 10 5 1 404 | |
3033 | Node 0, zone Normal 216 55 189 101 84 38 37 27 5 3 587 | |
37d5e699 | 3034 | .EE |
e3fb1b6b | 3035 | .RE |
2dad4c59 | 3036 | .IP |
b1aad373 MK |
3037 | In this example, there is one node containing three zones and there |
3038 | are 11 different chunk sizes. | |
3039 | If the page size is 4 kilobytes, then the first zone called | |
3040 | .I DMA | |
3041 | (on x86 the first 16 megabyte of memory) has 1 chunk of 4 kilobytes | |
3042 | (order 0) available and has 3 chunks of 4 megabytes (order 10) available. | |
2dad4c59 | 3043 | .IP |
b1aad373 MK |
3044 | If the memory is heavily fragmented, the counters for higher |
3045 | order chunks will be zero and allocation of large contiguous areas | |
3046 | will fail. | |
2dad4c59 | 3047 | .IP |
b1aad373 MK |
3048 | Further information about the zones can be found in |
3049 | .IR /proc/zoneinfo . | |
3050 | .TP | |
3051 | .I /proc/bus | |
7371ef9e | 3052 | Contains subdirectories for installed buses. |
b1aad373 MK |
3053 | .TP |
3054 | .I /proc/bus/pccard | |
3055 | Subdirectory for PCMCIA devices when | |
3056 | .B CONFIG_PCMCIA | |
3057 | is set at kernel compilation time. | |
3058 | .TP | |
fea681da MK |
3059 | .I /proc/bus/pccard/drivers |
3060 | .TP | |
3061 | .I /proc/bus/pci | |
c13182ef | 3062 | Contains various bus subdirectories and pseudo-files containing |
7371ef9e | 3063 | information about PCI buses, installed devices, and device |
c13182ef MK |
3064 | drivers. |
3065 | Some of these files are not ASCII. | |
fea681da MK |
3066 | .TP |
3067 | .I /proc/bus/pci/devices | |
59a40ed7 | 3068 | Information about PCI devices. |
c13182ef | 3069 | They may be accessed through |
fea681da MK |
3070 | .BR lspci (8) |
3071 | and | |
3072 | .BR setpci (8). | |
3073 | .TP | |
12b23dfe MK |
3074 | .IR /proc/cgroups " (since Linux 2.6.24)" |
3075 | See | |
3076 | .BR cgroups (7). | |
3077 | .TP | |
fea681da | 3078 | .I /proc/cmdline |
c13182ef MK |
3079 | Arguments passed to the Linux kernel at boot time. |
3080 | Often done via a boot manager such as | |
59a40ed7 MK |
3081 | .BR lilo (8) |
3082 | or | |
3083 | .BR grub (8). | |
f6e524c4 MK |
3084 | .TP |
3085 | .IR /proc/config.gz " (since Linux 2.6)" | |
3086 | This file exposes the configuration options that were used | |
c3d9780d | 3087 | to build the currently running kernel, |
f6e524c4 MK |
3088 | in the same format as they would be shown in the |
3089 | .I .config | |
3090 | file that resulted when configuring the kernel (using | |
3091 | .IR "make xconfig" , | |
3092 | .IR "make config" , | |
3093 | or similar). | |
3094 | The file contents are compressed; view or search them using | |
f78ed33a MK |
3095 | .BR zcat (1) |
3096 | and | |
3097 | .BR zgrep (1). | |
f6e524c4 | 3098 | As long as no changes have been made to the following file, |
250e01ec MK |
3099 | the contents of |
3100 | .I /proc/config.gz | |
37d5e699 MK |
3101 | are the same as those provided by: |
3102 | .IP | |
f6e524c4 | 3103 | .in +4n |
37d5e699 | 3104 | .EX |
c3074d70 | 3105 | cat /lib/modules/$(uname \-r)/build/.config |
37d5e699 | 3106 | .EE |
f6e524c4 | 3107 | .in |
250e01ec MK |
3108 | .IP |
3109 | .I /proc/config.gz | |
90878f7c | 3110 | is provided only if the kernel is configured with |
250e01ec | 3111 | .BR CONFIG_IKCONFIG_PROC . |
fea681da | 3112 | .TP |
577c0e20 MK |
3113 | .I /proc/crypto |
3114 | A list of the ciphers provided by the kernel crypto API. | |
3115 | For details, see the kernel | |
3116 | .I "Linux Kernel Crypto API" | |
3117 | documentation available under the kernel source directory | |
e94de168 ES |
3118 | .I Documentation/crypto/ |
3119 | .\" commit 3b72c814a8e8cd638e1ba0da4dfce501e9dff5af | |
3120 | (or | |
3121 | .I Documentation/DocBook | |
3122 | before 4.10; | |
3123 | the documentation can be built using a command such as | |
577c0e20 | 3124 | .IR "make htmldocs" |
e94de168 | 3125 | in the root directory of the kernel source tree). |
577c0e20 | 3126 | .TP |
fea681da MK |
3127 | .I /proc/cpuinfo |
3128 | This is a collection of CPU and system architecture dependent items, | |
3129 | for each supported architecture a different list. | |
3130 | Two common entries are \fIprocessor\fP which gives CPU number and | |
c13182ef MK |
3131 | \fIbogomips\fP; a system constant that is calculated |
3132 | during kernel initialization. | |
3133 | SMP machines have information for | |
fea681da | 3134 | each CPU. |
a091f002 MK |
3135 | The |
3136 | .BR lscpu (1) | |
3137 | command gathers its information from this file. | |
fea681da MK |
3138 | .TP |
3139 | .I /proc/devices | |
c13182ef MK |
3140 | Text listing of major numbers and device groups. |
3141 | This can be used by MAKEDEV scripts for consistency with the kernel. | |
fea681da MK |
3142 | .TP |
3143 | .IR /proc/diskstats " (since Linux 2.5.69)" | |
3144 | This file contains disk I/O statistics for each disk device. | |
66a9882e | 3145 | See the Linux kernel source file |
8a5fc410 MK |
3146 | .I ./Documentation/admin\-guide/iostats.rst |
3147 | (or | |
fea681da | 3148 | .I Documentation/iostats.txt |
8a5fc410 | 3149 | before Linux 5.3) |
fea681da MK |
3150 | for further information. |
3151 | .TP | |
3152 | .I /proc/dma | |
c13182ef | 3153 | This is a list of the registered \fIISA\fP DMA (direct memory access) |
fea681da MK |
3154 | channels in use. |
3155 | .TP | |
3156 | .I /proc/driver | |
3157 | Empty subdirectory. | |
3158 | .TP | |
3159 | .I /proc/execdomains | |
3160 | List of the execution domains (ABI personalities). | |
3161 | .TP | |
3162 | .I /proc/fb | |
097585ed MK |
3163 | Frame buffer information when |
3164 | .B CONFIG_FB | |
3165 | is defined during kernel compilation. | |
fea681da MK |
3166 | .TP |
3167 | .I /proc/filesystems | |
9ee4a2b6 MK |
3168 | A text listing of the filesystems which are supported by the kernel, |
3169 | namely filesystems which were compiled into the kernel or whose kernel | |
6387216b MK |
3170 | modules are currently loaded. |
3171 | (See also | |
fb477da2 | 3172 | .BR filesystems (5).) |
9ee4a2b6 | 3173 | If a filesystem is marked with "nodev", |
809d0164 | 3174 | this means that it does not require a block device to be mounted |
9ee4a2b6 | 3175 | (e.g., virtual filesystem, network filesystem). |
2dad4c59 | 3176 | .IP |
809d0164 MK |
3177 | Incidentally, this file may be used by |
3178 | .BR mount (8) | |
9ee4a2b6 MK |
3179 | when no filesystem is specified and it didn't manage to determine the |
3180 | filesystem type. | |
3181 | Then filesystems contained in this file are tried | |
809d0164 | 3182 | (excepted those that are marked with "nodev"). |
fea681da MK |
3183 | .TP |
3184 | .I /proc/fs | |
df352acc | 3185 | .\" FIXME Much more needs to be said about /proc/fs |
91085d85 | 3186 | .\" |
df352acc MK |
3187 | Contains subdirectories that in turn contain files |
3188 | with information about (certain) mounted filesystems. | |
fea681da MK |
3189 | .TP |
3190 | .I /proc/ide | |
3191 | This directory | |
59a40ed7 MK |
3192 | exists on systems with the IDE bus. |
3193 | There are directories for each IDE channel and attached device. | |
c13182ef | 3194 | Files include: |
2dad4c59 | 3195 | .IP |
a08ea57c | 3196 | .in +4n |
37d5e699 | 3197 | .EX |
fea681da MK |
3198 | cache buffer size in KB |
3199 | capacity number of sectors | |
3200 | driver driver version | |
3201 | geometry physical and logical geometry | |
9fdfa163 | 3202 | identify in hexadecimal |
fea681da | 3203 | media media type |
861d36ba | 3204 | model manufacturer\(aqs model number |
fea681da | 3205 | settings drive settings |
a6a5e521 MK |
3206 | smart_thresholds IDE disk management thresholds (in hex) |
3207 | smart_values IDE disk management values (in hex) | |
37d5e699 | 3208 | .EE |
a08ea57c | 3209 | .in |
2dad4c59 | 3210 | .IP |
c13182ef | 3211 | The |
fea681da MK |
3212 | .BR hdparm (8) |
3213 | utility provides access to this information in a friendly format. | |
3214 | .TP | |
3215 | .I /proc/interrupts | |
23ec6ff0 MK |
3216 | This is used to record the number of interrupts per CPU per IO device. |
3217 | Since Linux 2.6.24, | |
9ea5bc66 | 3218 | for the i386 and x86-64 architectures, at least, this also includes |
23ec6ff0 MK |
3219 | interrupts internal to the system (that is, not associated with a device |
3220 | as such), such as NMI (nonmaskable interrupt), LOC (local timer interrupt), | |
3221 | and for SMP systems, TLB (TLB flush interrupt), RES (rescheduling | |
3222 | interrupt), CAL (remote function call interrupt), and possibly others. | |
3223 | Very easy to read formatting, done in ASCII. | |
fea681da MK |
3224 | .TP |
3225 | .I /proc/iomem | |
3226 | I/O memory map in Linux 2.4. | |
3227 | .TP | |
3228 | .I /proc/ioports | |
c13182ef | 3229 | This is a list of currently registered Input-Output port regions that |
fea681da MK |
3230 | are in use. |
3231 | .TP | |
3232 | .IR /proc/kallsyms " (since Linux 2.5.71)" | |
3233 | This holds the kernel exported symbol definitions used by the | |
3234 | .BR modules (X) | |
3235 | tools to dynamically link and bind loadable modules. | |
3236 | In Linux 2.5.47 and earlier, a similar file with slightly different syntax | |
3237 | was named | |
3238 | .IR ksyms . | |
3239 | .TP | |
3240 | .I /proc/kcore | |
3241 | This file represents the physical memory of the system and is stored | |
c13182ef MK |
3242 | in the ELF core file format. |
3243 | With this pseudo-file, and an unstripped | |
9a67332e MK |
3244 | kernel |
3245 | .RI ( /usr/src/linux/vmlinux ) | |
3246 | binary, GDB can be used to | |
fea681da | 3247 | examine the current state of any kernel data structures. |
2dad4c59 | 3248 | .IP |
fea681da | 3249 | The total length of the file is the size of physical memory (RAM) plus |
ee8655b5 | 3250 | 4\ KiB. |
fea681da | 3251 | .TP |
653836fb MK |
3252 | .IR /proc/keys " (since Linux 2.6.10)" |
3253 | See | |
3254 | .BR keyrings (7). | |
3255 | .TP | |
184d797d | 3256 | .IR /proc/key\-users " (since Linux 2.6.10)" |
653836fb MK |
3257 | See |
3258 | .BR keyrings (7). | |
3259 | .TP | |
fea681da MK |
3260 | .I /proc/kmsg |
3261 | This file can be used instead of the | |
3262 | .BR syslog (2) | |
c13182ef MK |
3263 | system call to read kernel messages. |
3264 | A process must have superuser | |
fea681da | 3265 | privileges to read this file, and only one process should read this |
c13182ef MK |
3266 | file. |
3267 | This file should not be read if a syslog process is running | |
fea681da MK |
3268 | which uses the |
3269 | .BR syslog (2) | |
3270 | system call facility to log kernel messages. | |
2dad4c59 | 3271 | .IP |
fea681da | 3272 | Information in this file is retrieved with the |
c4517613 | 3273 | .BR dmesg (1) |
fea681da MK |
3274 | program. |
3275 | .TP | |
55d68a94 | 3276 | .IR /proc/kpagecgroup " (since Linux 4.3)" |
0e462d71 | 3277 | .\" commit 80ae2fdceba8313b0433f899bdd9c6c463291a17 |
55d68a94 OE |
3278 | This file contains a 64-bit inode number of |
3279 | the memory cgroup each page is charged to, | |
3280 | indexed by page frame number (see the discussion of | |
3281 | .IR /proc/[pid]/pagemap ). | |
3282 | .IP | |
3283 | The | |
3284 | .IR /proc/kpagecgroup | |
3285 | file is present only if the | |
3286 | .B CONFIG_MEMCG | |
3287 | kernel configuration option is enabled. | |
3288 | .TP | |
ff56ac8b MK |
3289 | .IR /proc/kpagecount " (since Linux 2.6.25)" |
3290 | This file contains a 64-bit count of the number of | |
3291 | times each physical page frame is mapped, | |
3292 | indexed by page frame number (see the discussion of | |
3293 | .IR /proc/[pid]/pagemap ). | |
3294 | .IP | |
3295 | The | |
3296 | .IR /proc/kpagecount | |
3297 | file is present only if the | |
3298 | .B CONFIG_PROC_PAGE_MONITOR | |
59d566a9 MK |
3299 | kernel configuration option is enabled. |
3300 | .TP | |
3301 | .IR /proc/kpageflags " (since Linux 2.6.25)" | |
ef4f4031 | 3302 | This file contains 64-bit masks corresponding to each physical page frame; |
59d566a9 MK |
3303 | it is indexed by page frame number (see the discussion of |
3304 | .IR /proc/[pid]/pagemap ). | |
3305 | The bits are as follows: | |
2dad4c59 | 3306 | .IP |
59d566a9 MK |
3307 | 0 - KPF_LOCKED |
3308 | 1 - KPF_ERROR | |
3309 | 2 - KPF_REFERENCED | |
3310 | 3 - KPF_UPTODATE | |
3311 | 4 - KPF_DIRTY | |
3312 | 5 - KPF_LRU | |
3313 | 6 - KPF_ACTIVE | |
3314 | 7 - KPF_SLAB | |
3315 | 8 - KPF_WRITEBACK | |
3316 | 9 - KPF_RECLAIM | |
3317 | 10 - KPF_BUDDY | |
3318 | 11 - KPF_MMAP (since Linux 2.6.31) | |
3319 | 12 - KPF_ANON (since Linux 2.6.31) | |
3320 | 13 - KPF_SWAPCACHE (since Linux 2.6.31) | |
3321 | 14 - KPF_SWAPBACKED (since Linux 2.6.31) | |
3322 | 15 - KPF_COMPOUND_HEAD (since Linux 2.6.31) | |
3323 | 16 - KPF_COMPOUND_TAIL (since Linux 2.6.31) | |
d0ffc687 | 3324 | 17 - KPF_HUGE (since Linux 2.6.31) |
59d566a9 MK |
3325 | 18 - KPF_UNEVICTABLE (since Linux 2.6.31) |
3326 | 19 - KPF_HWPOISON (since Linux 2.6.31) | |
3327 | 20 - KPF_NOPAGE (since Linux 2.6.31) | |
3328 | 21 - KPF_KSM (since Linux 2.6.32) | |
3329 | 22 - KPF_THP (since Linux 3.4) | |
5487da4c MK |
3330 | 23 - KPF_BALLOON (since Linux 3.18) |
3331 | .\" KPF_BALLOON: commit 09316c09dde33aae14f34489d9e3d243ec0d5938 | |
f38dfdf1 | 3332 | 24 - KPF_ZERO_PAGE (since Linux 4.0) |
c6f182bc | 3333 | .\" KPF_ZERO_PAGE: commit 56873f43abdcd574b25105867a990f067747b2f4 |
f38dfdf1 | 3334 | 25 - KPF_IDLE (since Linux 4.3) |
c6f182bc | 3335 | .\" KPF_IDLE: commit f074a8f49eb87cde95ac9d040ad5e7ea4f029738 |
2dad4c59 | 3336 | .IP |
59d566a9 MK |
3337 | For further details on the meanings of these bits, |
3338 | see the kernel source file | |
184d797d | 3339 | .IR Documentation/admin\-guide/mm/pagemap.rst . |
59d566a9 MK |
3340 | Before kernel 2.6.29, |
3341 | .\" commit ad3bdefe877afb47480418fdb05ecd42842de65e | |
3342 | .\" commit e07a4b9217d1e97d2f3a62b6b070efdc61212110 | |
3343 | .BR KPF_WRITEBACK , | |
3344 | .BR KPF_RECLAIM , | |
3345 | .BR KPF_BUDDY , | |
3346 | and | |
3347 | .BR KPF_LOCKED | |
3348 | did not report correctly. | |
3349 | .IP | |
3350 | The | |
3351 | .IR /proc/kpageflags | |
3352 | file is present only if the | |
3353 | .B CONFIG_PROC_PAGE_MONITOR | |
ff56ac8b MK |
3354 | kernel configuration option is enabled. |
3355 | .TP | |
93f18cbb | 3356 | .IR /proc/ksyms " (Linux 1.1.23\(en2.5.47)" |
fea681da MK |
3357 | See |
3358 | .IR /proc/kallsyms . | |
3359 | .TP | |
3360 | .I /proc/loadavg | |
6b05dc38 MK |
3361 | The first three fields in this file are load average figures |
3362 | giving the number of jobs in the run queue (state R) | |
fea681da MK |
3363 | or waiting for disk I/O (state D) averaged over 1, 5, and 15 minutes. |
3364 | They are the same as the load average numbers given by | |
3365 | .BR uptime (1) | |
3366 | and other programs. | |
6b05dc38 | 3367 | The fourth field consists of two numbers separated by a slash (/). |
78fc91ec EDB |
3368 | The first of these is the number of currently runnable kernel |
3369 | scheduling entities (processes, threads). | |
6b05dc38 MK |
3370 | The value after the slash is the number of kernel scheduling entities |
3371 | that currently exist on the system. | |
3372 | The fifth field is the PID of the process that was most | |
3373 | recently created on the system. | |
fea681da MK |
3374 | .TP |
3375 | .I /proc/locks | |
3376 | This file shows current file locks | |
3377 | .RB ( flock "(2) and " fcntl (2)) | |
3378 | and leases | |
3379 | .RB ( fcntl (2)). | |
f352b560 MK |
3380 | .IP |
3381 | An example of the content shown in this file is the following: | |
3382 | .IP | |
3383 | .in +4n | |
3384 | .EX | |
3385 | 1: POSIX ADVISORY READ 5433 08:01:7864448 128 128 | |
3386 | 2: FLOCK ADVISORY WRITE 2001 08:01:7864554 0 EOF | |
3387 | 3: FLOCK ADVISORY WRITE 1568 00:2f:32388 0 EOF | |
3388 | 4: POSIX ADVISORY WRITE 699 00:16:28457 0 EOF | |
3389 | 5: POSIX ADVISORY WRITE 764 00:16:21448 0 0 | |
3390 | 6: POSIX ADVISORY READ 3548 08:01:7867240 1 1 | |
3391 | 7: POSIX ADVISORY READ 3548 08:01:7865567 1826 2335 | |
184d797d | 3392 | 8: OFDLCK ADVISORY WRITE \-1 08:01:8713209 128 191 |
f352b560 MK |
3393 | .EE |
3394 | .in | |
3395 | .IP | |
3396 | The fields shown in each line are as follows: | |
3397 | .RS | |
3398 | .IP (1) 4 | |
3399 | The ordinal position of the lock in the list. | |
3400 | .IP (2) | |
3401 | The lock type. | |
3402 | Values that may appear here include: | |
3403 | .RS | |
3404 | .TP | |
3405 | .B FLOCK | |
3406 | This is a BSD file lock created using | |
3407 | .BR flock (2). | |
3408 | .TP | |
3409 | .B OFDLCK | |
3410 | This is an open file description (OFD) lock created using | |
3411 | .BR fcntl (2). | |
3412 | .TP | |
3413 | .B POSIX | |
3414 | This is a POSIX byte-range lock created using | |
3415 | .BR fcntl (2). | |
3416 | .RE | |
3417 | .IP (3) | |
3418 | Among the strings that can appear here are the following: | |
3419 | .RS | |
3420 | .TP | |
3421 | .B ADVISORY | |
3422 | This is an advisory lock. | |
3423 | .TP | |
3424 | .B MANDATORY | |
3425 | This is a mandatory lock. | |
3426 | .RE | |
3427 | .IP (4) | |
3428 | The type of lock. | |
3429 | Values that can appear here are: | |
3430 | .RS | |
3431 | .TP | |
3432 | .B READ | |
3433 | This is a POSIX or OFD read lock, or a BSD shared lock. | |
3434 | .TP | |
3435 | .B WRITE | |
3436 | This is a POSIX or OFD write lock, or a BSD exclusive lock. | |
3437 | .RE | |
3438 | .IP (5) | |
3439 | The PID of the process that owns the lock. | |
3440 | .IP | |
3441 | Because OFD locks are not owned by a single process | |
3442 | (since multiple processes may have file descriptors that | |
3443 | refer to the same open file description), | |
3444 | the value \-1 is displayed in this field for OFD locks. | |
3445 | (Before kernel 4.14, | |
52f842a5 | 3446 | .\" commit 9d5b86ac13c573795525ecac6ed2db39ab23e2a8 |
f352b560 MK |
3447 | a bug meant that the PID of the process that |
3448 | initially acquired the lock was displayed instead of the value \-1.) | |
3449 | .IP (6) | |
3450 | Three colon-separated subfields that identify the major and minor device | |
3451 | ID of the device containing the filesystem where the locked file resides, | |
3452 | followed by the inode number of the locked file. | |
3453 | .IP (7) | |
3454 | The byte offset of the first byte of the lock. | |
3455 | For BSD locks, this value is always 0. | |
3456 | .IP (8) | |
3457 | The byte offset of the last byte of the lock. | |
3458 | .B EOF | |
3459 | in this field means that the lock extends to the end of the file. | |
3460 | For BSD locks, the value shown is always | |
3461 | .IR EOF . | |
3462 | .RE | |
3463 | .IP | |
8fb9b45a MK |
3464 | Since Linux 4.9, |
3465 | .\" commit d67fd44f697dff293d7cdc29af929241b669affe | |
3466 | the list of locks shown in | |
3467 | .I /proc/locks | |
3468 | is filtered to show just the locks for the processes in the PID | |
3469 | namespace (see | |
3470 | .BR pid_namespaces (7)) | |
3471 | for which the | |
3472 | .I /proc | |
3473 | filesystem was mounted. | |
1dbe854b | 3474 | (In the initial PID namespace, |
8fb9b45a MK |
3475 | there is no filtering of the records shown in this file.) |
3476 | .IP | |
9f1002a1 MK |
3477 | The |
3478 | .BR lslocks (8) | |
3479 | command provides a bit more information about each lock. | |
fea681da | 3480 | .TP |
89dd5f8a | 3481 | .IR /proc/malloc " (only up to and including Linux 2.2)" |
59a40ed7 | 3482 | .\" It looks like this only ever did something back in 1.0 days |
90878f7c | 3483 | This file is present only if |
89dd5f8a | 3484 | .B CONFIG_DEBUG_MALLOC |
097585ed | 3485 | was defined during compilation. |
fea681da MK |
3486 | .TP |
3487 | .I /proc/meminfo | |
77b802ec MK |
3488 | This file reports statistics about memory usage on the system. |
3489 | It is used by | |
fea681da MK |
3490 | .BR free (1) |
3491 | to report the amount of free and used memory (both physical and swap) | |
3492 | on the system as well as the shared memory and buffers used by the | |
3493 | kernel. | |
3ba3d5b1 MK |
3494 | Each line of the file consists of a parameter name, followed by a colon, |
3495 | the value of the parameter, and an option unit of measurement (e.g., "kB"). | |
3496 | The list below describes the parameter names and | |
3497 | the format specifier required to read the field value. | |
3498 | Except as noted below, | |
3499 | all of the fields have been present since at least Linux 2.6.0. | |
86cf87d7 | 3500 | Some fields are displayed only if the kernel was configured |
3ba3d5b1 MK |
3501 | with various options; those dependencies are noted in the list. |
3502 | .RS | |
3503 | .TP | |
3504 | .IR MemTotal " %lu" | |
449dd4e2 | 3505 | Total usable RAM (i.e., physical RAM minus a few reserved |
99e91586 | 3506 | bits and the kernel binary code). |
3ba3d5b1 MK |
3507 | .TP |
3508 | .IR MemFree " %lu" | |
7bccb7d4 DP |
3509 | The sum of |
3510 | .IR LowFree + HighFree . | |
3ba3d5b1 | 3511 | .TP |
8b4b1f68 MK |
3512 | .IR MemAvailable " %lu (since Linux 3.14)" |
3513 | An estimate of how much memory is available for starting new | |
3514 | applications, without swapping. | |
3515 | .TP | |
3ba3d5b1 | 3516 | .IR Buffers " %lu" |
99e91586 | 3517 | Relatively temporary storage for raw disk blocks that |
c7169ee5 | 3518 | shouldn't get tremendously large (20 MB or so). |
3ba3d5b1 MK |
3519 | .TP |
3520 | .IR Cached " %lu" | |
3521 | In-memory cache for files read from the disk (the page cache). | |
3522 | Doesn't include | |
3523 | .IR SwapCached . | |
3524 | .TP | |
3525 | .IR SwapCached " %lu" | |
3526 | Memory that once was swapped out, is swapped back in but | |
3527 | still also is in the swap file. | |
fa1d2749 | 3528 | (If memory pressure is high, these pages |
3ba3d5b1 | 3529 | don't need to be swapped out again because they are already |
99e91586 | 3530 | in the swap file. |
3ba3d5b1 MK |
3531 | This saves I/O.) |
3532 | .TP | |
3533 | .IR Active " %lu" | |
3534 | Memory that has been used more recently and usually not | |
3535 | reclaimed unless absolutely necessary. | |
3536 | .TP | |
3537 | .IR Inactive " %lu" | |
3538 | Memory which has been less recently used. | |
3539 | It is more eligible to be reclaimed for other purposes. | |
3540 | .TP | |
3541 | .IR Active(anon) " %lu (since Linux 2.6.28)" | |
3542 | [To be documented.] | |
3543 | .TP | |
3544 | .IR Inactive(anon) " %lu (since Linux 2.6.28)" | |
3545 | [To be documented.] | |
3546 | .TP | |
3547 | .IR Active(file) " %lu (since Linux 2.6.28)" | |
3548 | [To be documented.] | |
3549 | .TP | |
3550 | .IR Inactive(file) " %lu (since Linux 2.6.28)" | |
3551 | [To be documented.] | |
3552 | .TP | |
3553 | .IR Unevictable " %lu (since Linux 2.6.28)" | |
3554 | (From Linux 2.6.28 to 2.6.30, | |
3555 | \fBCONFIG_UNEVICTABLE_LRU\fP was required.) | |
3556 | [To be documented.] | |
3557 | .TP | |
46fbfc07 | 3558 | .IR Mlocked " %lu (since Linux 2.6.28)" |
3ba3d5b1 MK |
3559 | (From Linux 2.6.28 to 2.6.30, |
3560 | \fBCONFIG_UNEVICTABLE_LRU\fP was required.) | |
3561 | [To be documented.] | |
3562 | .TP | |
3563 | .IR HighTotal " %lu" | |
3564 | (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) | |
3565 | Total amount of highmem. | |
af2d18b2 | 3566 | Highmem is all memory above \(ti860 MB of physical memory. |
3ba3d5b1 MK |
3567 | Highmem areas are for use by user-space programs, |
3568 | or for the page cache. | |
3569 | The kernel must use tricks to access | |
3570 | this memory, making it slower to access than lowmem. | |
3571 | .TP | |
0dbe186a | 3572 | .IR HighFree " %lu" |
3ba3d5b1 MK |
3573 | (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
3574 | Amount of free highmem. | |
3575 | .TP | |
0dbe186a | 3576 | .IR LowTotal " %lu" |
3ba3d5b1 MK |
3577 | (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
3578 | Total amount of lowmem. | |
3579 | Lowmem is memory which can be used for everything that | |
3580 | highmem can be used for, but it is also available for the | |
3581 | kernel's use for its own data structures. | |
3582 | Among many other things, | |
99e91586 | 3583 | it is where everything from |
7bccb7d4 DP |
3584 | .I Slab |
3585 | is allocated. | |
3ba3d5b1 MK |
3586 | Bad things happen when you're out of lowmem. |
3587 | .TP | |
0dbe186a | 3588 | .IR LowFree " %lu" |
3ba3d5b1 MK |
3589 | (Starting with Linux 2.6.19, \fBCONFIG_HIGHMEM\fP is required.) |
3590 | Amount of free lowmem. | |
3591 | .TP | |
3592 | .IR MmapCopy " %lu (since Linux 2.6.29)" | |
99e91586 DP |
3593 | .RB ( CONFIG_MMU |
3594 | is required.) | |
3ba3d5b1 MK |
3595 | [To be documented.] |
3596 | .TP | |
3597 | .IR SwapTotal " %lu" | |
3598 | Total amount of swap space available. | |
3599 | .TP | |
3600 | .IR SwapFree " %lu" | |
c16d4f25 | 3601 | Amount of swap space that is currently unused. |
3ba3d5b1 MK |
3602 | .TP |
3603 | .IR Dirty " %lu" | |
3604 | Memory which is waiting to get written back to the disk. | |
3605 | .TP | |
3606 | .IR Writeback " %lu" | |
3607 | Memory which is actively being written back to the disk. | |
3608 | .TP | |
3609 | .IR AnonPages " %lu (since Linux 2.6.18)" | |
3610 | Non-file backed pages mapped into user-space page tables. | |
3611 | .TP | |
3612 | .IR Mapped " %lu" | |
fda70f5b MK |
3613 | Files which have been mapped into memory (with |
3614 | .BR mmap (2)), | |
3615 | such as libraries. | |
3ba3d5b1 MK |
3616 | .TP |
3617 | .IR Shmem " %lu (since Linux 2.6.32)" | |
eb775c04 MK |
3618 | Amount of memory consumed in |
3619 | .BR tmpfs (5) | |
3620 | filesystems. | |
3ba3d5b1 | 3621 | .TP |
7375eaab MK |
3622 | .IR KReclaimable " %lu (since Linux 4.20)" |
3623 | Kernel allocations that the kernel will attempt to reclaim | |
3624 | under memory pressure. | |
3625 | Includes | |
3626 | .I SReclaimable | |
3627 | (below), and other direct allocations with a shrinker. | |
3628 | .TP | |
3ba3d5b1 MK |
3629 | .IR Slab " %lu" |
3630 | In-kernel data structures cache. | |
5a5bde70 MK |
3631 | (See |
3632 | .BR slabinfo (5).) | |
3ba3d5b1 MK |
3633 | .TP |
3634 | .IR SReclaimable " %lu (since Linux 2.6.19)" | |
7bccb7d4 DP |
3635 | Part of |
3636 | .IR Slab , | |
3637 | that might be reclaimed, such as caches. | |
3ba3d5b1 MK |
3638 | .TP |
3639 | .IR SUnreclaim " %lu (since Linux 2.6.19)" | |
7bccb7d4 DP |
3640 | Part of |
3641 | .IR Slab , | |
3642 | that cannot be reclaimed on memory pressure. | |
3ba3d5b1 MK |
3643 | .TP |
3644 | .IR KernelStack " %lu (since Linux 2.6.32)" | |
3645 | Amount of memory allocated to kernel stacks. | |
3646 | .TP | |
3647 | .IR PageTables " %lu (since Linux 2.6.18)" | |
3648 | Amount of memory dedicated to the lowest level of page tables. | |
3649 | .TP | |
3650 | .IR Quicklists " %lu (since Linux 2.6.27)" | |
3651 | (\fBCONFIG_QUICKLIST\fP is required.) | |
3652 | [To be documented.] | |
3653 | .TP | |
3654 | .IR NFS_Unstable " %lu (since Linux 2.6.18)" | |
3655 | NFS pages sent to the server, but not yet committed to stable storage. | |
3656 | .TP | |
3657 | .IR Bounce " %lu (since Linux 2.6.18)" | |
3658 | Memory used for block device "bounce buffers". | |
3659 | .TP | |
3660 | .IR WritebackTmp " %lu (since Linux 2.6.26)" | |
3661 | Memory used by FUSE for temporary writeback buffers. | |
3662 | .TP | |
3663 | .IR CommitLimit " %lu (since Linux 2.6.10)" | |
cd7b6c40 MK |
3664 | This is the total amount of memory currently available to |
3665 | be allocated on the system, expressed in kilobytes. | |
90878f7c MK |
3666 | This limit is adhered to |
3667 | only if strict overcommit accounting is enabled (mode 2 in | |
cd7b6c40 MK |
3668 | .IR /proc/sys/vm/overcommit_memory ). |
3669 | The limit is calculated according to the formula described under | |
3670 | .IR /proc/sys/vm/overcommit_memory . | |
3671 | For further details, see the kernel source file | |
184d797d | 3672 | .IR Documentation/vm/overcommit\-accounting.rst . |
3ba3d5b1 MK |
3673 | .TP |
3674 | .IR Committed_AS " %lu" | |
3675 | The amount of memory presently allocated on the system. | |
3676 | The committed memory is a sum of all of the memory which | |
3677 | has been allocated by processes, even if it has not been | |
3678 | "used" by them as of yet. | |
c7169ee5 | 3679 | A process which allocates 1 GB of memory (using |
3ba3d5b1 | 3680 | .BR malloc (3) |
c7169ee5 MK |
3681 | or similar), but touches only 300 MB of that memory will show up |
3682 | as using only 300 MB of memory even if it has the address space | |
3683 | allocated for the entire 1 GB. | |
2dad4c59 | 3684 | .IP |
c7169ee5 | 3685 | This 1 GB is memory which has been "committed" to by the VM |
3ba3d5b1 | 3686 | and can be used at any time by the allocating application. |
cd7b6c40 | 3687 | With strict overcommit enabled on the system (mode 2 in |
d9e0f03d | 3688 | .IR /proc/sys/vm/overcommit_memory ), |
3ba3d5b1 MK |
3689 | allocations which would exceed the |
3690 | .I CommitLimit | |
cd7b6c40 | 3691 | will not be permitted. |
3ba3d5b1 MK |
3692 | This is useful if one needs to guarantee that processes will not |
3693 | fail due to lack of memory once that memory has been successfully allocated. | |
3694 | .TP | |
3695 | .IR VmallocTotal " %lu" | |
3696 | Total size of vmalloc memory area. | |
3697 | .TP | |
3698 | .IR VmallocUsed " %lu" | |
2fc546f9 MK |
3699 | Amount of vmalloc area which is used. |
3700 | Since Linux 4.4, | |
3701 | .\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0 | |
3702 | this field is no longer calculated, and is hard coded as 0. | |
3703 | See | |
bfe9256a | 3704 | .IR /proc/vmallocinfo . |
3ba3d5b1 MK |
3705 | .TP |
3706 | .IR VmallocChunk " %lu" | |
2fc546f9 MK |
3707 | Largest contiguous block of vmalloc area which is free. |
3708 | Since Linux 4.4, | |
3709 | .\" commit a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0 | |
3710 | this field is no longer calculated and is hard coded as 0. | |
3711 | See | |
bfe9256a | 3712 | .IR /proc/vmallocinfo . |
3ba3d5b1 MK |
3713 | .TP |
3714 | .IR HardwareCorrupted " %lu (since Linux 2.6.32)" | |
3715 | (\fBCONFIG_MEMORY_FAILURE\fP is required.) | |
3716 | [To be documented.] | |
3717 | .TP | |
f7bbc79d MK |
3718 | .IR LazyFree " %lu (since Linux 4.12)" |
3719 | Shows the amount of memory marked by | |
3720 | .BR madvise (2) | |
3721 | .BR MADV_FREE . | |
3722 | .TP | |
3ba3d5b1 MK |
3723 | .IR AnonHugePages " %lu (since Linux 2.6.38)" |
3724 | (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) | |
7fac88a9 | 3725 | Non-file backed huge pages mapped into user-space page tables. |
3ba3d5b1 | 3726 | .TP |
4ad958e1 MK |
3727 | .IR ShmemHugePages " %lu (since Linux 4.8)" |
3728 | (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) | |
4e07c70f MK |
3729 | Memory used by shared memory (shmem) and |
3730 | .BR tmpfs (5) | |
c7169ee5 | 3731 | allocated with huge pages. |
4ad958e1 MK |
3732 | .TP |
3733 | .IR ShmemPmdMapped " %lu (since Linux 4.8)" | |
3734 | (\fBCONFIG_TRANSPARENT_HUGEPAGE\fP is required.) | |
956e74b4 | 3735 | Shared memory mapped into user space with huge pages. |
4ad958e1 | 3736 | .TP |
43179f55 MK |
3737 | .IR CmaTotal " %lu (since Linux 3.1)" |
3738 | Total CMA (Contiguous Memory Allocator) pages. | |
3739 | (\fBCONFIG_CMA\fP is required.) | |
3740 | .TP | |
3741 | .IR CmaFree " %lu (since Linux 3.1)" | |
3742 | Free CMA (Contiguous Memory Allocator) pages. | |
3743 | (\fBCONFIG_CMA\fP is required.) | |
3744 | .TP | |
3ba3d5b1 MK |
3745 | .IR HugePages_Total " %lu" |
3746 | (\fBCONFIG_HUGETLB_PAGE\fP is required.) | |
3747 | The size of the pool of huge pages. | |
3748 | .TP | |
3749 | .IR HugePages_Free " %lu" | |
3750 | (\fBCONFIG_HUGETLB_PAGE\fP is required.) | |
3751 | The number of huge pages in the pool that are not yet allocated. | |
3752 | .TP | |
3753 | .IR HugePages_Rsvd " %lu (since Linux 2.6.17)" | |
3754 | (\fBCONFIG_HUGETLB_PAGE\fP is required.) | |
3755 | This is the number of huge pages for | |
3756 | which a commitment to allocate from the pool has been made, | |
3757 | but no allocation has yet been made. | |
3758 | These reserved huge pages | |
3759 | guarantee that an application will be able to allocate a | |
3760 | huge page from the pool of huge pages at fault time. | |
3761 | .TP | |
aa8a6b4f | 3762 | .IR HugePages_Surp " %lu (since Linux 2.6.24)" |
3ba3d5b1 MK |
3763 | (\fBCONFIG_HUGETLB_PAGE\fP is required.) |
3764 | This is the number of huge pages in | |
3765 | the pool above the value in | |
3766 | .IR /proc/sys/vm/nr_hugepages . | |
3767 | The maximum number of surplus huge pages is controlled by | |
3768 | .IR /proc/sys/vm/nr_overcommit_hugepages . | |
3769 | .TP | |
3770 | .IR Hugepagesize " %lu" | |
3771 | (\fBCONFIG_HUGETLB_PAGE\fP is required.) | |
3772 | The size of huge pages. | |
d5268de1 MK |
3773 | .TP |
3774 | .IR DirectMap4k " %lu (since Linux 2.6.27)" | |
c7169ee5 | 3775 | Number of bytes of RAM linearly mapped by kernel in 4 kB pages. |
d5268de1 MK |
3776 | (x86.) |
3777 | .TP | |
3778 | .IR DirectMap4M " %lu (since Linux 2.6.27)" | |
c7169ee5 | 3779 | Number of bytes of RAM linearly mapped by kernel in 4 MB pages. |
d5268de1 MK |
3780 | (x86 with |
3781 | .BR CONFIG_X86_64 | |
3782 | or | |
3783 | .BR CONFIG_X86_PAE | |
3784 | enabled.) | |
3785 | .TP | |
3786 | .IR DirectMap2M " %lu (since Linux 2.6.27)" | |
c7169ee5 | 3787 | Number of bytes of RAM linearly mapped by kernel in 2 MB pages. |
d5268de1 MK |
3788 | (x86 with neither |
3789 | .BR CONFIG_X86_64 | |
3790 | nor | |
3791 | .BR CONFIG_X86_PAE | |
3792 | enabled.) | |
3793 | .TP | |
3794 | .IR DirectMap1G " %lu (since Linux 2.6.27)" | |
3795 | (x86 with | |
3796 | .BR CONFIG_X86_64 | |
3797 | and | |
3798 | .B CONFIG_X86_DIRECT_GBPAGES | |
3799 | enabled.) | |
3ba3d5b1 | 3800 | .RE |
fea681da | 3801 | .TP |
aa341984 MK |
3802 | .I /proc/modules |
3803 | A text list of the modules that have been loaded by the system. | |
3804 | See also | |
3805 | .BR lsmod (8). | |
3806 | .TP | |
fea681da | 3807 | .I /proc/mounts |
c1eea65a | 3808 | Before kernel 2.4.19, this file was a list |
9ee4a2b6 | 3809 | of all the filesystems currently mounted on the system. |
ef5b47f6 MK |
3810 | With the introduction of per-process mount namespaces in Linux 2.4.19 (see |
3811 | .BR mount_namespaces (7)), | |
3812 | this file became a link to | |
c1eea65a | 3813 | .IR /proc/self/mounts , |
525a8b54 | 3814 | which lists the mounts of the process's own mount namespace. |
fea681da | 3815 | The format of this file is documented in |
31e9a9ec | 3816 | .BR fstab (5). |
fea681da | 3817 | .TP |
fea681da | 3818 | .I /proc/mtrr |
c13182ef | 3819 | Memory Type Range Registers. |
66a9882e | 3820 | See the Linux kernel source file |
8a5fc410 MK |
3821 | .I Documentation/x86/mtrr.rst |
3822 | (or | |
a8999e1f ES |
3823 | .I Documentation/x86/mtrr.txt |
3824 | .\" commit 7225e75144b9718cbbe1820d9c011c809d5773fd | |
8a5fc410 | 3825 | before Linux 5.2, or |
cfe70b66 | 3826 | .I Documentation/mtrr.txt |
a8999e1f | 3827 | before Linux 2.6.28) |
fea681da MK |
3828 | for details. |
3829 | .TP | |
3830 | .I /proc/net | |
ccb4bcdc MK |
3831 | This directory contains various files and subdirectories containing |
3832 | information about the networking layer. | |
3833 | The files contain ASCII structures and are, | |
59a40ed7 MK |
3834 | therefore, readable with |
3835 | .BR cat (1). | |
c13182ef | 3836 | However, the standard |
fea681da MK |
3837 | .BR netstat (8) |
3838 | suite provides much cleaner access to these files. | |
2dad4c59 | 3839 | .IP |
9fb88bc8 MK |
3840 | With the advent of network namespaces, |
3841 | various information relating to the network stack is virtualized (see | |
40002795 | 3842 | .BR network_namespaces (7)). |
9fb88bc8 MK |
3843 | Thus, since Linux 2.6.25, |
3844 | .\" commit e9720acd728a46cb40daa52c99a979f7c4ff195c | |
3845 | .IR /proc/net | |
3846 | is a symbolic link to the directory | |
3847 | .IR /proc/self/net , | |
3848 | which contains the same files and directories as listed below. | |
3849 | However, these files and directories now expose information | |
3850 | for the network namespace of which the process is a member. | |
fea681da MK |
3851 | .TP |
3852 | .I /proc/net/arp | |
3853 | This holds an ASCII readable dump of the kernel ARP table used for | |
c13182ef | 3854 | address resolutions. |
01d0a447 | 3855 | It will show both dynamically learned and preprogrammed ARP entries. |
c13182ef | 3856 | The format is: |
c1a022dc | 3857 | .IP |
e3fb1b6b | 3858 | .in +4n |
c1a022dc | 3859 | .EX |
fea681da MK |
3860 | IP address HW type Flags HW address Mask Device |
3861 | 192.168.0.50 0x1 0x2 00:50:BF:25:68:F3 * eth0 | |
3862 | 192.168.0.250 0x1 0xc 00:00:00:00:00:00 * eth0 | |
c1a022dc | 3863 | .EE |
fea681da | 3864 | .in |
c1a022dc | 3865 | .IP |
6c04f928 | 3866 | Here "IP address" is the IPv4 address of the machine and the "HW type" |
c13182ef MK |
3867 | is the hardware type of the address from RFC\ 826. |
3868 | The flags are the internal | |
9a67332e MK |
3869 | flags of the ARP structure (as defined in |
3870 | .IR /usr/include/linux/if_arp.h ) | |
3871 | and | |
6c04f928 | 3872 | the "HW address" is the data link layer mapping for that IP address if |
fea681da MK |
3873 | it is known. |
3874 | .TP | |
3875 | .I /proc/net/dev | |
c13182ef MK |
3876 | The dev pseudo-file contains network device status information. |
3877 | This gives | |
3878 | the number of received and sent packets, the number of errors and | |
fea681da | 3879 | collisions |
c13182ef MK |
3880 | and other basic statistics. |
3881 | These are used by the | |
fea681da | 3882 | .BR ifconfig (8) |
c13182ef MK |
3883 | program to report device status. |
3884 | The format is: | |
c1a022dc | 3885 | .IP |
c1a022dc | 3886 | .EX |
184d797d | 3887 | Inter\-| Receive | Transmit |
fea681da MK |
3888 | face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed |
3889 | lo: 2776770 11307 0 0 0 0 0 0 2776770 11307 0 0 0 0 0 0 | |
3890 | eth0: 1215645 2751 0 0 0 0 0 0 1782404 4324 0 0 0 427 0 0 | |
3891 | ppp0: 1622270 5552 1 0 0 0 0 0 354130 5669 0 0 0 0 0 0 | |
3892 | tap0: 7714 81 0 0 0 0 0 0 7714 81 0 0 0 0 0 0 | |
c1a022dc | 3893 | .EE |
fea681da MK |
3894 | .\" .TP |
3895 | .\" .I /proc/net/ipx | |
3896 | .\" No information. | |
3897 | .\" .TP | |
3898 | .\" .I /proc/net/ipx_route | |
3899 | .\" No information. | |
3900 | .TP | |
3901 | .I /proc/net/dev_mcast | |
3902 | Defined in | |
3903 | .IR /usr/src/linux/net/core/dev_mcast.c : | |
37d5e699 | 3904 | .IP |
161b8eda | 3905 | .in +4n |
37d5e699 | 3906 | .EX |
9fdfa163 | 3907 | indx interface_name dmi_u dmi_g dmi_address |
fea681da MK |
3908 | 2 eth0 1 0 01005e000001 |
3909 | 3 eth1 1 0 01005e000001 | |
3910 | 4 eth2 1 0 01005e000001 | |
37d5e699 | 3911 | .EE |
fea681da | 3912 | .in |
fea681da MK |
3913 | .TP |
3914 | .I /proc/net/igmp | |
c13182ef MK |
3915 | Internet Group Management Protocol. |
3916 | Defined in | |
fea681da MK |
3917 | .IR /usr/src/linux/net/core/igmp.c . |
3918 | .TP | |
3919 | .I /proc/net/rarp | |
3920 | This file uses the same format as the | |
3921 | .I arp | |
3922 | file and contains the current reverse mapping database used to provide | |
3923 | .BR rarp (8) | |
c13182ef MK |
3924 | reverse address lookup services. |
3925 | If RARP is not configured into the | |
fea681da MK |
3926 | kernel, |
3927 | this file will not be present. | |
3928 | .TP | |
3929 | .I /proc/net/raw | |
c13182ef MK |
3930 | Holds a dump of the RAW socket table. |
3931 | Much of the information is not of | |
fea681da | 3932 | use |
c13182ef | 3933 | apart from debugging. |
6c04f928 | 3934 | The "sl" value is the kernel hash slot for the |
fea681da | 3935 | socket, |
6c04f928 MK |
3936 | the "local_address" is the local address and protocol number pair. |
3937 | \&"St" is | |
c13182ef MK |
3938 | the internal status of the socket. |
3939 | The "tx_queue" and "rx_queue" are the | |
fea681da | 3940 | outgoing and incoming data queue in terms of kernel memory usage. |
94e9d9fe | 3941 | The "tr", "tm\->when", and "rexmits" fields are not used by RAW. |
fdc196f5 MK |
3942 | The "uid" |
3943 | field holds the effective UID of the creator of the socket. | |
fea681da MK |
3944 | .\" .TP |
3945 | .\" .I /proc/net/route | |
3946 | .\" No information, but looks similar to | |
3947 | .\" .BR route (8). | |
3948 | .TP | |
3949 | .I /proc/net/snmp | |
c13182ef | 3950 | This file holds the ASCII data needed for the IP, ICMP, TCP, and UDP |
fea681da | 3951 | management |
763f0e47 | 3952 | information bases for an SNMP agent. |
fea681da MK |
3953 | .TP |
3954 | .I /proc/net/tcp | |
c13182ef MK |
3955 | Holds a dump of the TCP socket table. |
3956 | Much of the information is not | |
3957 | of use apart from debugging. | |
3958 | The "sl" value is the kernel hash slot | |
6beb1671 MK |
3959 | for the socket, the "local_address" is the local address and port number pair. |
3960 | The "rem_address" is the remote address and port number pair | |
6c04f928 MK |
3961 | (if connected). |
3962 | \&"St" is the internal status of the socket. | |
3963 | The "tx_queue" and "rx_queue" are the | |
fea681da | 3964 | outgoing and incoming data queue in terms of kernel memory usage. |
94e9d9fe | 3965 | The "tr", "tm\->when", and "rexmits" fields hold internal information of |
f33774c4 | 3966 | the kernel socket state and are useful only for debugging. |
fdc196f5 MK |
3967 | The "uid" |
3968 | field holds the effective UID of the creator of the socket. | |
fea681da MK |
3969 | .TP |
3970 | .I /proc/net/udp | |
c13182ef MK |
3971 | Holds a dump of the UDP socket table. |
3972 | Much of the information is not of | |
3973 | use apart from debugging. | |
3974 | The "sl" value is the kernel hash slot for the | |
6beb1671 MK |
3975 | socket, the "local_address" is the local address and port number pair. |
3976 | The "rem_address" is the remote address and port number pair | |
f2d607ee MK |
3977 | (if connected). |
3978 | "St" is the internal status of the socket. | |
fea681da | 3979 | The "tx_queue" and "rx_queue" are the outgoing and incoming data queue |
c13182ef | 3980 | in terms of kernel memory usage. |
94e9d9fe | 3981 | The "tr", "tm\->when", and "rexmits" fields |
c13182ef | 3982 | are not used by UDP. |
fdc196f5 MK |
3983 | The "uid" |
3984 | field holds the effective UID of the creator of the socket. | |
fea681da | 3985 | The format is: |
c1a022dc | 3986 | .IP |
c1a022dc | 3987 | .EX |
94e9d9fe | 3988 | sl local_address rem_address st tx_queue rx_queue tr rexmits tm\->when uid |
fea681da MK |
3989 | 1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0 |
3990 | 1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0 | |
3991 | 1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 | |
c1a022dc | 3992 | .EE |
fea681da MK |
3993 | .TP |
3994 | .I /proc/net/unix | |
008f1ecc | 3995 | Lists the UNIX domain sockets present within the system and their |
c13182ef MK |
3996 | status. |
3997 | The format is: | |
c1a022dc | 3998 | .IP |
c1a022dc | 3999 | .EX |
9d30b1a6 MW |
4000 | Num RefCount Protocol Flags Type St Inode Path |
4001 | 0: 00000002 00000000 00000000 0001 03 42 | |
4002 | 1: 00000001 00000000 00010000 0001 01 1948 /dev/printer | |
c1a022dc | 4003 | .EE |
c1a022dc | 4004 | .IP |
756f55f6 MK |
4005 | The fields are as follows: |
4006 | .RS | |
4007 | .TP 10 | |
4008 | .IR Num : | |
4009 | the kernel table slot number. | |
4010 | .TP | |
4011 | .IR RefCount : | |
4012 | the number of users of the socket. | |
4013 | .TP | |
4014 | .IR Protocol : | |
4015 | currently always 0. | |
4016 | .TP | |
4017 | .IR Flags : | |
4018 | the internal kernel flags holding the status of the socket. | |
4019 | .TP | |
4020 | .IR Type : | |
a405066e MK |
4021 | the socket type. |
4022 | For | |
4023 | .BR SOCK_STREAM | |
4024 | sockets, this is 0001; for | |
4025 | .BR SOCK_DGRAM | |
4026 | sockets, it is 0002; and for | |
4027 | .BR SOCK_SEQPACKET | |
4028 | sockets, it is 0005. | |
756f55f6 MK |
4029 | .TP |
4030 | .IR St : | |
4031 | the internal state of the socket. | |
4032 | .TP | |
9d30b1a6 MW |
4033 | .IR Inode : |
4034 | the inode number of the socket. | |
4035 | .TP | |
756f55f6 | 4036 | .IR Path : |
590ba7e5 | 4037 | the bound pathname (if any) of the socket. |
8f8a46fb MK |
4038 | Sockets in the abstract namespace are included in the list, |
4039 | and are shown with a | |
4040 | .I Path | |
4041 | that commences with the character '@'. | |
756f55f6 | 4042 | .RE |
fea681da | 4043 | .TP |
ed8de0e4 | 4044 | .I /proc/net/netfilter/nfnetlink_queue |
6f858d5c | 4045 | This file contains information about netfilter user-space queueing, if used. |
f2d607ee MK |
4046 | Each line represents a queue. |
4047 | Queues that have not been subscribed to | |
6f858d5c | 4048 | by user space are not shown. |
37d5e699 MK |
4049 | .IP |
4050 | .in +4n | |
4051 | .EX | |
ed8de0e4 FW |
4052 | 1 4207 0 2 65535 0 0 0 1 |
4053 | (1) (2) (3)(4) (5) (6) (7) (8) | |
37d5e699 MK |
4054 | .EE |
4055 | .in | |
ed8de0e4 FW |
4056 | .IP |
4057 | The fields in each line are: | |
4058 | .RS 7 | |
4059 | .TP 5 | |
4060 | (1) | |
f2d607ee MK |
4061 | The ID of the queue. |
4062 | This matches what is specified in the | |
ed8de0e4 FW |
4063 | .B \-\-queue\-num |
4064 | or | |
4065 | .B \-\-queue\-balance | |
4066 | options to the | |
4067 | .BR iptables (8) | |
f2d607ee MK |
4068 | NFQUEUE target. |
4069 | See | |
184d797d | 4070 | .BR iptables\-extensions (8) |
ed8de0e4 FW |
4071 | for more information. |
4072 | .TP | |
4073 | (2) | |
7672e08e | 4074 | The netlink port ID subscribed to the queue. |
ed8de0e4 FW |
4075 | .TP |
4076 | (3) | |
4077 | The number of packets currently queued and waiting to be processed by | |
4078 | the application. | |
4079 | .TP | |
4080 | (4) | |
f2d607ee MK |
4081 | The copy mode of the queue. |
4082 | It is either 1 (metadata only) or 2 | |
6f858d5c | 4083 | (also copy payload data to user space). |
ed8de0e4 FW |
4084 | .TP |
4085 | (5) | |
1dea597b | 4086 | Copy range; that is, how many bytes of packet payload should be copied to |
6f858d5c | 4087 | user space at most. |
ed8de0e4 FW |
4088 | .TP |
4089 | (6) | |
f2d607ee MK |
4090 | queue dropped. |
4091 | Number of packets that had to be dropped by the kernel because | |
6f858d5c | 4092 | too many packets are already waiting for user space to send back the mandatory |
ed8de0e4 FW |
4093 | accept/drop verdicts. |
4094 | .TP | |
4095 | (7) | |
f2d607ee MK |
4096 | queue user dropped. |
4097 | Number of packets that were dropped within the netlink | |
4098 | subsystem. | |
4099 | Such drops usually happen when the corresponding socket buffer is | |
6f858d5c | 4100 | full; that is, user space is not able to read messages fast enough. |
ed8de0e4 FW |
4101 | .TP |
4102 | (8) | |
f2d607ee MK |
4103 | sequence number. |
4104 | Every queued packet is associated with a (32-bit) | |
11fd5e7c | 4105 | monotonically increasing sequence number. |
ed8de0e4 FW |
4106 | This shows the ID of the most recent packet queued. |
4107 | .RE | |
4108 | .IP | |
f33774c4 | 4109 | The last number exists only for compatibility reasons and is always 1. |
ed8de0e4 | 4110 | .TP |
fea681da | 4111 | .I /proc/partitions |
f042d149 MK |
4112 | Contains the major and minor numbers of each partition as well as the number |
4113 | of 1024-byte blocks and the partition name. | |
fea681da MK |
4114 | .TP |
4115 | .I /proc/pci | |
4116 | This is a listing of all PCI devices found during kernel initialization | |
4117 | and their configuration. | |
2dad4c59 | 4118 | .IP |
59a40ed7 MK |
4119 | This file has been deprecated in favor of a new |
4120 | .I /proc | |
2990d781 MK |
4121 | interface for PCI |
4122 | .RI ( /proc/bus/pci ). | |
4123 | It became optional in Linux 2.2 (available with | |
4124 | .B CONFIG_PCI_OLD_PROC | |
4125 | set at kernel compilation). | |
24b74457 | 4126 | It became once more nonoptionally enabled in Linux 2.4. |
2990d781 MK |
4127 | Next, it was deprecated in Linux 2.6 (still available with |
4128 | .B CONFIG_PCI_LEGACY_PROC | |
4129 | set), and finally removed altogether since Linux 2.6.17. | |
43d42cc0 | 4130 | .\" FIXME Document /proc/sched_debug (since Linux 2.6.23) |
69119dc7 | 4131 | .\" See also /proc/[pid]/sched |
caea7868 MK |
4132 | .TP |
4133 | .IR /proc/profile " (since Linux 2.4)" | |
4134 | This file is present only if the kernel was booted with the | |
4135 | .I profile=1 | |
4136 | command-line option. | |
4137 | It exposes kernel profiling information in a binary format for use by | |
4138 | .BR readprofile (1). | |
4139 | Writing (e.g., an empty string) to this file resets the profiling counters; | |
4140 | on some architectures, | |
4141 | writing a binary integer "profiling multiplier" of size | |
4142 | .IR sizeof(int) | |
8a3ac89a | 4143 | sets the profiling interrupt frequency. |
fea681da MK |
4144 | .TP |
4145 | .I /proc/scsi | |
59a40ed7 MK |
4146 | A directory with the |
4147 | .I scsi | |
4148 | mid-level pseudo-file and various SCSI low-level | |
2990d781 MK |
4149 | driver directories, |
4150 | which contain a file for each SCSI host in this system, all of | |
c13182ef MK |
4151 | which give the status of some part of the SCSI IO subsystem. |
4152 | These files contain ASCII structures and are, therefore, readable with | |
2990d781 | 4153 | .BR cat (1). |
2dad4c59 | 4154 | .IP |
c13182ef | 4155 | You can also write to some of the files to reconfigure the subsystem or |
59a40ed7 | 4156 | switch certain features on or off. |
fea681da MK |
4157 | .TP |
4158 | .I /proc/scsi/scsi | |
c13182ef | 4159 | This is a listing of all SCSI devices known to the kernel. |
59a40ed7 | 4160 | The listing is similar to the one seen during bootup. |
184d797d | 4161 | scsi currently supports only the \fIadd\-single\-device\fP command which |
59a40ed7 | 4162 | allows root to add a hotplugged device to the list of known devices. |
2dad4c59 | 4163 | .IP |
59a40ed7 | 4164 | The command |
37d5e699 | 4165 | .IP |
59a40ed7 | 4166 | .in +4n |
37d5e699 | 4167 | .EX |
184d797d | 4168 | echo \(aqscsi add\-single\-device 1 0 5 0\(aq > /proc/scsi/scsi |
37d5e699 | 4169 | .EE |
59a40ed7 | 4170 | .in |
37d5e699 | 4171 | .IP |
c13182ef MK |
4172 | will cause |
4173 | host scsi1 to scan on SCSI channel 0 for a device on ID 5 LUN 0. | |
4174 | If there | |
fea681da MK |
4175 | is already a device known on this address or the address is invalid, an |
4176 | error will be returned. | |
4177 | .TP | |
4178 | .I /proc/scsi/[drivername] | |
c13182ef MK |
4179 | \fI[drivername]\fP can currently be NCR53c7xx, aha152x, aha1542, aha1740, |
4180 | aic7xxx, buslogic, eata_dma, eata_pio, fdomain, in2000, pas16, qlogic, | |
184d797d | 4181 | scsi_debug, seagate, t128, u15\-24f, ultrastore, or wd7000. |
c13182ef | 4182 | These directories show up for all drivers that registered at least one |
59a40ed7 | 4183 | SCSI HBA. |
c13182ef | 4184 | Every directory contains one file per registered host. |
59a40ed7 | 4185 | Every host-file is named after the number the host was assigned during |
c13182ef | 4186 | initialization. |
2dad4c59 | 4187 | .IP |
c13182ef | 4188 | Reading these files will usually show driver and host configuration, |
f78ed33a | 4189 | statistics, and so on. |
2dad4c59 | 4190 | .IP |
fea681da MK |
4191 | Writing to these files allows different things on different hosts. |
4192 | For example, with the \fIlatency\fP and \fInolatency\fP commands, | |
4193 | root can switch on and off command latency measurement code in the | |
c13182ef MK |
4194 | eata_dma driver. |
4195 | With the \fIlockup\fP and \fIunlock\fP commands, | |
4196 | root can control bus lockups simulated by the scsi_debug driver. | |
fea681da MK |
4197 | .TP |
4198 | .I /proc/self | |
59a40ed7 MK |
4199 | This directory refers to the process accessing the |
4200 | .I /proc | |
9ee4a2b6 | 4201 | filesystem, |
59a40ed7 MK |
4202 | and is identical to the |
4203 | .I /proc | |
4204 | directory named by the process ID of the same process. | |
fea681da MK |
4205 | .TP |
4206 | .I /proc/slabinfo | |
c13182ef | 4207 | Information about kernel caches. |
c13182ef | 4208 | See |
fea681da MK |
4209 | .BR slabinfo (5) |
4210 | for details. | |
4211 | .TP | |
4212 | .I /proc/stat | |
c13182ef MK |
4213 | kernel/system statistics. |
4214 | Varies with architecture. | |
4215 | Common | |
fea681da MK |
4216 | entries include: |
4217 | .RS | |
4218 | .TP | |
46f6dbe8 ES |
4219 | .I cpu 10132153 290696 3084719 46828483 16683 0 25195 0 175628 0 |
4220 | .TQ | |
4221 | .I cpu0 1393280 32966 572056 13343292 6130 0 17875 0 23933 0 | |
bfbfcd18 | 4222 | The amount of time, measured in units of |
268f000b MK |
4223 | USER_HZ (1/100ths of a second on most architectures, use |
4224 | .IR sysconf(_SC_CLK_TCK) | |
4225 | to obtain the right value), | |
b81087ab | 4226 | .\" 1024 on Alpha and ia64 |
46f6dbe8 ES |
4227 | that the system ("cpu" line) or the specific CPU ("cpu\fIN\fR" line) |
4228 | spent in various states: | |
ae3b8047 MK |
4229 | .RS |
4230 | .TP | |
4231 | .I user | |
ea0841f6 | 4232 | (1) Time spent in user mode. |
ae3b8047 MK |
4233 | .TP |
4234 | .I nice | |
0633f951 | 4235 | (2) Time spent in user mode with low priority (nice). |
9f1b9726 | 4236 | .TP |
ae3b8047 | 4237 | .I system |
0633f951 | 4238 | (3) Time spent in system mode. |
ae3b8047 MK |
4239 | .TP |
4240 | .I idle | |
ea0841f6 | 4241 | (4) Time spent in the idle task. |
bea08fec | 4242 | .\" FIXME . Actually, the following info about the /proc/stat 'cpu' field |
e04a1f93 MK |
4243 | .\" does not seem to be quite right (at least in 2.6.12 or 3.6): |
4244 | .\" the idle time in /proc/uptime does not quite match this value | |
4245 | This value should be USER_HZ times the | |
4cb1deb7 MK |
4246 | second entry in the |
4247 | .I /proc/uptime | |
4248 | pseudo-file. | |
ae3b8047 MK |
4249 | .TP |
4250 | .IR iowait " (since Linux 2.5.41)" | |
ea0841f6 | 4251 | (5) Time waiting for I/O to complete. |
e0a73a31 MK |
4252 | This value is not reliable, for the following reasons: |
4253 | .\" See kernel commit 9c240d757658a3ae9968dd309e674c61f07c7f48 | |
4254 | .RS | |
4255 | .IP 1. 3 | |
4256 | The CPU will not wait for I/O to complete; | |
4257 | iowait is the time that a task is waiting for I/O to complete. | |
4258 | When a CPU goes into idle state for outstanding task I/O, | |
4259 | another task will be scheduled on this CPU. | |
4260 | .IP 2. | |
4261 | On a multi-core CPU, | |
4262 | the task waiting for I/O to complete is not running on any CPU, | |
4263 | so the iowait of each CPU is difficult to calculate. | |
4264 | .IP 3. | |
4265 | The value in this field may | |
4266 | .I decrease | |
4267 | in certain conditions. | |
2d3fb75b | 4268 | .RE |
ae3b8047 | 4269 | .TP |
d6bec36e MK |
4270 | .IR irq " (since Linux 2.6.0)" |
4271 | .\" Precisely: Linux 2.6.0-test4 | |
ea0841f6 | 4272 | (6) Time servicing interrupts. |
ae3b8047 | 4273 | .TP |
c7169ee5 | 4274 | .IR softirq " (since Linux 2.6.0)" |
d6bec36e | 4275 | .\" Precisely: Linux 2.6.0-test4 |
ea0841f6 | 4276 | (7) Time servicing softirqs. |
ae3b8047 MK |
4277 | .TP |
4278 | .IR steal " (since Linux 2.6.11)" | |
ea0841f6 | 4279 | (8) Stolen time, which is the time spent in other operating systems when |
9de1f6cc | 4280 | running in a virtualized environment |
ae3b8047 MK |
4281 | .TP |
4282 | .IR guest " (since Linux 2.6.24)" | |
0633f951 | 4283 | (9) Time spent running a virtual CPU for guest |
afef1764 | 4284 | operating systems under the control of the Linux kernel. |
14c06953 | 4285 | .\" See Changelog entry for 5e84cfde51cf303d368fcb48f22059f37b3872de |
d4fd4120 MK |
4286 | .TP |
4287 | .IR guest_nice " (since Linux 2.6.33)" | |
4288 | .\" commit ce0e7b28fb75cb003cfc8d0238613aaf1c55e797 | |
4289 | (10) Time spent running a niced guest (virtual CPU for guest | |
4290 | operating systems under the control of the Linux kernel). | |
ae3b8047 | 4291 | .RE |
fea681da MK |
4292 | .TP |
4293 | \fIpage 5741 1808\fP | |
4294 | The number of pages the system paged in and the number that were paged | |
4295 | out (from disk). | |
4296 | .TP | |
4297 | \fIswap 1 0\fP | |
4298 | The number of swap pages that have been brought in and out. | |
4299 | .TP | |
bea08fec | 4300 | .\" FIXME . The following is not the full picture for the 'intr' of |
777f5a9e | 4301 | .\" /proc/stat on 2.6: |
fea681da | 4302 | \fIintr 1462898\fP |
bfbfcd18 MK |
4303 | This line shows counts of interrupts serviced since boot time, |
4304 | for each of the possible system interrupts. | |
d63ff76e | 4305 | The first column is the total of all interrupts serviced |
d6a56978 MK |
4306 | including unnumbered architecture specific interrupts; |
4307 | each subsequent column is the total for that particular numbered interrupt. | |
d63ff76e | 4308 | Unnumbered interrupts are not shown, only summed into the total. |
fea681da MK |
4309 | .TP |
4310 | \fIdisk_io: (2,0):(31,30,5764,1,2) (3,0):\fP... | |
636297e9 | 4311 | (major,disk_idx):(noinfo, read_io_ops, blks_read, write_io_ops, blks_written) |
bfbfcd18 MK |
4312 | .br |
4313 | (Linux 2.4 only) | |
fea681da MK |
4314 | .TP |
4315 | \fIctxt 115315\fP | |
4316 | The number of context switches that the system underwent. | |
4317 | .TP | |
4318 | \fIbtime 769041601\fP | |
f49c451a | 4319 | boot time, in seconds since the Epoch, 1970-01-01 00:00:00 +0000 (UTC). |
fea681da MK |
4320 | .TP |
4321 | \fIprocesses 86031\fP | |
4322 | Number of forks since boot. | |
bfbfcd18 MK |
4323 | .TP |
4324 | \fIprocs_running 6\fP | |
4325 | Number of processes in runnable state. | |
5fab2e7c | 4326 | (Linux 2.5.45 onward.) |
bfbfcd18 MK |
4327 | .TP |
4328 | \fIprocs_blocked 2\fP | |
4329 | Number of processes blocked waiting for I/O to complete. | |
5fab2e7c | 4330 | (Linux 2.5.45 onward.) |
76f6f102 ES |
4331 | .TP |
4332 | .I softirq 229245889 94 60001584 13619 5175704 2471304 28 51212741 59130143 0 51240672 | |
4333 | .\" commit d3d64df21d3d0de675a0d3ffa7c10514f3644b30 | |
4334 | This line shows the number of softirq for all CPUs. | |
4335 | The first column is the total of all softirqs and | |
4336 | each subsequent column is the total for particular softirq. | |
d7f23d0b | 4337 | (Linux 2.6.31 onward.) |
fea681da MK |
4338 | .RE |
4339 | .TP | |
4340 | .I /proc/swaps | |
c13182ef MK |
4341 | Swap areas in use. |
4342 | See also | |
fea681da MK |
4343 | .BR swapon (8). |
4344 | .TP | |
4345 | .I /proc/sys | |
4346 | This directory (present since 1.3.57) contains a number of files | |
4347 | and subdirectories corresponding to kernel variables. | |
13648a9c | 4348 | These variables can be read and in some cases modified using |
9ee4a2b6 | 4349 | the \fI/proc\fP filesystem, and the (deprecated) |
fea681da | 4350 | .BR sysctl (2) |
c13182ef | 4351 | system call. |
2dad4c59 | 4352 | .IP |
d1a71985 | 4353 | String values may be terminated by either \(aq\e0\(aq or \(aq\en\(aq. |
2dad4c59 | 4354 | .IP |
84ff8c1e | 4355 | Integer and long values may be written either in decimal or in |
0629df8b | 4356 | hexadecimal notation (e.g., 0x3FFF). |
e8aa7100 MK |
4357 | When writing multiple integer or long values, these may be separated |
4358 | by any of the following whitespace characters: | |
d1a71985 | 4359 | \(aq\ \(aq, \(aq\et\(aq, or \(aq\en\(aq. |
e8aa7100 | 4360 | Using other separators leads to the error |
84ff8c1e | 4361 | .BR EINVAL . |
fea681da | 4362 | .TP |
6ab7c0aa | 4363 | .IR /proc/sys/abi " (since Linux 2.4.10)" |
fea681da | 4364 | This directory may contain files with application binary information. |
6ab7c0aa | 4365 | .\" On some systems, it is not present. |
66a9882e | 4366 | See the Linux kernel source file |
8a5fc410 MK |
4367 | .I Documentation/sysctl/abi.rst |
4368 | (or | |
6ab7c0aa | 4369 | .I Documentation/sysctl/abi.txt |
8a5fc410 | 4370 | before Linux 5.3) |
6ab7c0aa | 4371 | for more information. |
fea681da MK |
4372 | .TP |
4373 | .I /proc/sys/debug | |
4374 | This directory may be empty. | |
4375 | .TP | |
4376 | .I /proc/sys/dev | |
e2badfdf | 4377 | This directory contains device-specific information (e.g., |
9a67332e | 4378 | .IR dev/cdrom/info ). |
fea681da MK |
4379 | On |
4380 | some systems, it may be empty. | |
4381 | .TP | |
4382 | .I /proc/sys/fs | |
49236d3c | 4383 | This directory contains the files and subdirectories for kernel variables |
9ee4a2b6 | 4384 | related to filesystems. |
fea681da | 4385 | .TP |
b49c2acb | 4386 | .IR /proc/sys/fs/aio\-max\-nr " and " /proc/sys/fs/aio\-nr " (since Linux 2.6.4)" |
cd415e73 | 4387 | .I aio\-nr |
9f51687a MK |
4388 | is the running total of the number of events specified by |
4389 | .BR io_setup (2) | |
4390 | calls for all currently active AIO contexts. | |
4391 | If | |
cd415e73 | 4392 | .I aio\-nr |
9f51687a | 4393 | reaches |
cd415e73 | 4394 | .IR aio\-max\-nr , |
9f51687a MK |
4395 | then |
4396 | .BR io_setup (2) | |
4397 | will fail with the error | |
4398 | .BR EAGAIN . | |
4399 | Raising | |
cd415e73 | 4400 | .I aio\-max\-nr |
9f51687a MK |
4401 | does not result in the preallocation or resizing |
4402 | of any kernel data structures. | |
4403 | .TP | |
fea681da | 4404 | .I /proc/sys/fs/binfmt_misc |
c13182ef | 4405 | Documentation for files in this directory can be found |
a2923df0 | 4406 | in the Linux kernel source in the file |
184d797d | 4407 | .IR Documentation/admin\-guide/binfmt\-misc.rst |
a2923df0 MK |
4408 | (or in |
4409 | .IR Documentation/binfmt_misc.txt | |
4410 | on older kernels). | |
fea681da | 4411 | .TP |
184d797d | 4412 | .IR /proc/sys/fs/dentry\-state " (since Linux 2.2)" |
59a40ed7 MK |
4413 | This file contains information about the status of the |
4414 | directory cache (dcache). | |
4415 | The file contains six numbers, | |
81533e83 | 4416 | .IR nr_dentry ", " nr_unused ", " age_limit " (age in seconds)," |
59a40ed7 | 4417 | .I want_pages |
fea681da | 4418 | (pages requested by system) and two dummy values. |
59a40ed7 MK |
4419 | .RS |
4420 | .IP * 2 | |
4421 | .I nr_dentry | |
4422 | is the number of allocated dentries (dcache entries). | |
4423 | This field is unused in Linux 2.2. | |
4424 | .IP * | |
4425 | .I nr_unused | |
4426 | is the number of unused dentries. | |
4427 | .IP * | |
4428 | .I age_limit | |
4429 | .\" looks like this is unused in kernels 2.2 to 2.6 | |
4430 | is the age in seconds after which dcache entries | |
4431 | can be reclaimed when memory is short. | |
4432 | .IP * | |
4433 | .I want_pages | |
4434 | .\" looks like this is unused in kernels 2.2 to 2.6 | |
c7094399 | 4435 | is nonzero when the kernel has called shrink_dcache_pages() and the |
fea681da | 4436 | dcache isn't pruned yet. |
59a40ed7 | 4437 | .RE |
fea681da | 4438 | .TP |
184d797d | 4439 | .I /proc/sys/fs/dir\-notify\-enable |
fea681da MK |
4440 | This file can be used to disable or enable the |
4441 | .I dnotify | |
4442 | interface described in | |
4443 | .BR fcntl (2) | |
4444 | on a system-wide basis. | |
4445 | A value of 0 in this file disables the interface, | |
4446 | and a value of 1 enables it. | |
4447 | .TP | |
184d797d | 4448 | .I /proc/sys/fs/dquot\-max |
fea681da MK |
4449 | This file shows the maximum number of cached disk quota entries. |
4450 | On some (2.4) systems, it is not present. | |
4451 | If the number of free cached disk quota entries is very low and | |
4452 | you have some awesome number of simultaneous system users, | |
4453 | you might want to raise the limit. | |
4454 | .TP | |
184d797d | 4455 | .I /proc/sys/fs/dquot\-nr |
fea681da MK |
4456 | This file shows the number of allocated disk quota |
4457 | entries and the number of free disk quota entries. | |
4458 | .TP | |
24cb4a4b | 4459 | .IR /proc/sys/fs/epoll " (since Linux 2.6.28)" |
242b46af MK |
4460 | This directory contains the file |
4461 | .IR max_user_watches , | |
24cb4a4b MK |
4462 | which can be used to limit the amount of kernel memory consumed by the |
4463 | .I epoll | |
4464 | interface. | |
4465 | For further details, see | |