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PROC(5)			   Linux Programmer's Manual		       PROC(5)



NAME
       proc - process information pseudo-filesystem

DESCRIPTION
       The  proc filesystem is a pseudo-filesystem which provides an interface
       to kernel data structures.  It is commonly mounted at /proc.   Most  of
       it is read-only, but some files allow kernel variables to be changed.

   Mount options
       The proc filesystem supports the following mount options:

       hidepid=n (since Linux 3.3)
	      This   option   controls	who  can  access  the  information  in
	      /proc/[pid] directories.	The argument, n, is one of the follow-
	      ing values:

	      0	  Everybody  may  access all /proc/[pid] directories.  This is
		  the traditional behavior, and	 the  default  if  this	 mount
		  option is not specified.

	      1	  Users	 may  not  access  files and subdirectories inside any
		  /proc/[pid]  directories  but	 their	own  (the  /proc/[pid]
		  directories  themselves  remain  visible).   Sensitive files
		  such as /proc/[pid]/cmdline and /proc/[pid]/status  are  now
		  protected  against other users.  This makes it impossible to
		  learn whether any user is running  a	specific  program  (so
		  long	as  the program doesn't otherwise reveal itself by its
		  behavior).

	      2	  As for mode 1, but in addition the  /proc/[pid]  directories
		  belonging  to other users become invisible.  This means that
		  /proc/[pid] entries can no longer be used  to	 discover  the
		  PIDs	on  the	 system.   This	 doesn't  hide the fact that a
		  process with a specific PID value exists (it can be  learned
		  by  other  means,  for  example,  by "kill -0 $PID"), but it
		  hides a process's UID and  GID,  which  could	 otherwise  be
		  learned  by  employing  stat(2)  on a /proc/[pid] directory.
		  This greatly complicates an  attacker's  task	 of  gathering
		  information	about  running	processes  (e.g.,  discovering
		  whether some daemon is  running  with	 elevated  privileges,
		  whether  another  user  is  running  some sensitive program,
		  whether other users are running any program at all,  and  so
		  on).

       gid=gid (since Linux 3.3)
	      Specifies	 the  ID  of  a	 group whose members are authorized to
	      learn  process  information  otherwise  prohibited  by   hidepid
	      (ie/e/,  users  in this group behave as though /proc was mounted
	      with hidepid=0.  This group should be used instead of approaches
	      such as putting nonroot users into the sudoers(5) file.

   Files and directories
       The  following  list  describes many of the files and directories under
       the /proc hierarchy.

       /proc/[pid]
	      There is a numerical subdirectory for each running process;  the
	      subdirectory is named by the process ID.	Each such subdirectory
	      contains the following pseudo-files and directories.

       /proc/[pid]/attr
	      The files in this directory provide an API for security modules.
	      The  contents  of	 this directory are files that can be read and
	      written in  order	 to  set  security-related  attributes.	  This
	      directory	 was  added  to support SELinux, but the intention was
	      that the API be general enough to support	 other	security  mod-
	      ules.   For  the purpose of explanation, examples of how SELinux
	      uses these files are provided below.

	      This directory is present only if the kernel was configured with
	      CONFIG_SECURITY.

       /proc/[pid]/attr/current (since Linux 2.6.0)
	      The  contents  of	 this  file  represent	the  current  security
	      attributes of the process.

	      In SELinux, this file is used to get the security context	 of  a
	      process.	 Prior to Linux 2.6.11, this file could not be used to
	      set the security context (a  write  was  always  denied),	 since
	      SELinux  limited	process security transitions to execve(2) (see
	      the description of /proc/[pid]/attr/exec, below).	  Since	 Linux
	      2.6.11,  SELinux	lifted	this  restriction and began supporting
	      "set" operations via writes to this node if authorized  by  pol-
	      icy,  although use of this operation is only suitable for appli-
	      cations that are trusted	to  maintain  any  desired  separation
	      between  the  old	 and  new  security  contexts.	Prior to Linux
	      2.6.28, SELinux did not allow threads  within  a	multi-threaded
	      process  to set their security context via this node as it would
	      yield an	inconsistency  among  the  security  contexts  of  the
	      threads  sharing	the  same  memory  space.  Since Linux 2.6.28,
	      SELinux lifted this restriction and began supporting "set" oper-
	      ations  for  threads  within  a multithreaded process if the new
	      security context is bounded by the old security  context,	 where
	      the  bounded  relation  is defined in policy and guarantees that
	      the new security context has a subset of the permissions of  the
	      old security context.  Other security modules may choose to sup-
	      port "set" operations via writes to this node.

       /proc/[pid]/attr/exec (since Linux 2.6.0)
	      This file represents the attributes to  assign  to  the  process
	      upon a subsequent execve(2).

	      In  SELinux,  this is needed to support role/domain transitions,
	      and execve(2) is the preferred point to  make  such  transitions
	      because  it offers better control over the initialization of the
	      process in the new security label and the inheritance of	state.
	      In SELinux, this attribute is reset on execve(2) so that the new
	      program reverts to the default behavior for any execve(2)	 calls
	      that  it	may  make.  In SELinux, a process can set only its own
	      /proc/[pid]/attr/exec attribute.

       /proc/[pid]/attr/fscreate (since Linux 2.6.0)
	      This file represents the attributes to assign to	files  created
	      by  subsequent  calls  to	 open(2),  mkdir(2),  symlink(2),  and
	      mknod(2)

	      SELinux employs this file to support creation of a  file	(using
	      the  aforementioned  system  calls)  in  a secure state, so that
	      there is no risk of inappropriate access being obtained  between
	      the  time	 of creation and the time that attributes are set.  In
	      SELinux, this attribute is reset on execve(2), so that  the  new
	      program  reverts	to  the default behavior for any file creation
	      calls it may make, but the attribute will persist across	multi-
	      ple file creation calls within a program unless it is explicitly
	      reset.   In  SELinux,  a	process	  can	set   only   its   own
	      /proc/[pid]/attr/fscreate attribute.

       /proc/[pid]/attr/prev (since Linux 2.6.0)
	      This  file  contains  the security context of the process before
	      the  last	 execve(2);   that   is,   the	 previous   value   of
	      /proc/[pid]/attr/current.

       /proc/[pid]/attr/keycreate (since Linux 2.6.18)
	      If  a process writes a security context into this file, all sub-
	      sequently created keys (add_key(2)) will be  labeled  with  this
	      context.	 For  further  information, see the kernel source file
	      Documentation/keys.txt.

       /proc/[pid]/attr/socketcreate (since Linux 2.6.18)
	      If a process writes a security context into this file, all  sub-
	      sequently created sockets will be labeled with this context.

       /proc/[pid]/auxv (since 2.6.0-test7)
	      This  contains  the  contents of the ELF interpreter information
	      passed to the process at exec time.  The format is one  unsigned
	      long  ID	plus one unsigned long value for each entry.  The last
	      entry contains two zeros.	 See also getauxval(3).

       /proc/[pid]/cgroup (since Linux 2.6.24)
	      This file describes control groups  to  which  the  process/task
	      belongs.	 For each cgroup hierarchy there is one entry contain-
	      ing colon-separated fields of the form:

		  5:cpuacct,cpu,cpuset:/daemons

	      The colon-separated fields are, from left to right:

		  1. hierarchy ID number

		  2. set of subsystems bound to the hierarchy

		  3. control group in  the  hierarchy  to  which  the  process
		     belongs

	      This  file is present only if the CONFIG_CGROUPS kernel configu-
	      ration option is enabled.

       /proc/[pid]/clear_refs (since Linux 2.6.22)

	      This is a	 write-only  file,  writable  only  by	owner  of  the
	      process.

	      The following values may be written to the file:

	      1 (since Linux 2.6.22)
		     Reset  the	 PG_Referenced and ACCESSED/YOUNG bits for all
		     the pages associated with the  process.   (Before	kernel
		     2.6.32,  writing  any nonzero value to this file had this
		     effect.)

	      2 (since Linux 2.6.32)
		     Reset the PG_Referenced and ACCESSED/YOUNG bits  for  all
		     anonymous pages associated with the process.

	      3 (since Linux 2.6.32)
		     Reset  the	 PG_Referenced and ACCESSED/YOUNG bits for all
		     file-mapped pages associated with the process.

	      Clearing the PG_Referenced and ACCESSED/YOUNG  bits  provides  a
	      method  to  measure  approximately  how much memory a process is
	      using.  One first inspects the values in the "Referenced" fields
	      for  the	VMAs  shown in /proc/[pid]/smaps to get an idea of the
	      memory footprint of the process.	One then clears the  PG_Refer-
	      enced  and  ACCESSED/YOUNG  bits	and,  after some measured time
	      interval, once again inspects the	 values	 in  the  "Referenced"
	      fields  to  get an idea of the change in memory footprint of the
	      process during the measured interval.  If one is interested only
	      in  inspecting the selected mapping types, then the value 2 or 3
	      can be used instead of 1.

	      A further value can be written to affect a different bit:

	      4 (since Linux 3.11)
		     Clear the soft-dirty bit for  all	the  pages  associated
		     with  the	process.   This	 is  used (in conjunction with
		     /proc/[pid]/pagemap) by the check-point restore system to
		     discover which pages of a process have been dirtied since
		     the file /proc/[pid]/clear_refs was written to.

	      Writing any value to  /proc/[pid]/clear_refs  other  than	 those
	      listed above has no effect.

	      The  /proc/[pid]/clear_refs  file	 is  present  only if the CON-
	      FIG_PROC_PAGE_MONITOR kernel configuration option is enabled.

       /proc/[pid]/cmdline
	      This read-only file holds the  complete  command	line  for  the
	      process,	unless	the  process is a zombie.  In the latter case,
	      there is nothing in this file: that is, a read on this file will
	      return  0 characters.  The command-line arguments appear in this
	      file as a set of strings separated by null bytes ('\0'), with  a
	      further null byte after the last string.

       /proc/[pid]/comm (since Linux 2.6.33)
	      This file exposes the process's comm value--that is, the command
	      name associated with the process.	 Different threads in the same
	      process	may   have   different	comm  values,  accessible  via
	      /proc/[pid]/task/[tid]/comm.   A	thread	may  modify  its  comm
	      value,  or  that of any of other thread in the same thread group
	      (see the discussion of CLONE_THREAD in clone(2)), by writing  to
	      the   file   /proc/self/task/[tid]/comm.	 Strings  longer  than
	      TASK_COMM_LEN (16) characters are silently truncated.

	      This file provides a superset of the  prctl(2)  PR_SET_NAME  and
	      PR_GET_NAME operations, and is employed by pthread_setname_np(3)
	      when used to rename threads other than the caller.

       /proc/[pid]/coredump_filter (since Linux 2.6.23)
	      See core(5).

       /proc/[pid]/cpuset (since Linux 2.6.12)
	      See cpuset(7).

       /proc/[pid]/cwd
	      This is a symbolic link to the current working directory of  the
	      process.	 To  find out the current working directory of process
	      20, for instance, you can do this:

		  $ cd /proc/20/cwd; /bin/pwd

	      Note that the pwd command is often a shell built-in,  and	 might
	      not work properly.  In bash(1), you may use pwd -P.

	      In  a  multithreaded process, the contents of this symbolic link
	      are not available if the	main  thread  has  already  terminated
	      (typically by calling pthread_exit(3)).

       /proc/[pid]/environ
	      This file contains the environment for the process.  The entries
	      are separated by null bytes ('\0'), and there may be a null byte
	      at  the  end.   Thus, to print out the environment of process 1,
	      you would do:

		  $ strings /proc/1/environ

       /proc/[pid]/exe
	      Under Linux 2.2 and later, this file is a symbolic link contain-
	      ing  the actual pathname of the executed command.	 This symbolic
	      link can be dereferenced normally; attempting to	open  it  will
	      open  the	 executable.  You can even type /proc/[pid]/exe to run
	      another copy of the same executable that is being run by process
	      [pid].   If  the	pathname  has been unlinked, the symbolic link
	      will contain the string '(deleted)'  appended  to	 the  original
	      pathname.	 In a multithreaded process, the contents of this sym-
	      bolic link are not available if the main thread has already ter-
	      minated (typically by calling pthread_exit(3)).

	      Under Linux 2.0 and earlier, /proc/[pid]/exe is a pointer to the
	      binary which was executed, and appears as a  symbolic  link.   A
	      readlink(2)  call	 on this file under Linux 2.0 returns a string
	      in the format:

		  [device]:inode

	      For example, [0301]:1502 would be inode 1502 on device major  03
	      (IDE,  MFM,  etc. drives) minor 01 (first partition on the first
	      drive).

	      find(1) with the -inum option can be used to locate the file.

       /proc/[pid]/fd/
	      This is a subdirectory containing one entry for each file	 which
	      the process has open, named by its file descriptor, and which is
	      a symbolic link to the actual file.  Thus, 0 is standard	input,
	      1 standard output, 2 standard error, and so on.

	      For  file descriptors for pipes and sockets, the entries will be
	      symbolic links whose content is the file type with the inode.  A
	      readlink(2) call on this file returns a string in the format:

		  type:[inode]

	      For  example, socket:[2248868] will be a socket and its inode is
	      2248868.	For sockets, that inode	 can  be  used	to  find  more
	      information in one of the files under /proc/net/.

	      For  file	 descriptors  that  have no corresponding inode (e.g.,
	      file descriptors produced by epoll_create(2),  eventfd(2),  ino-
	      tify_init(2),  signalfd(2), and timerfd(2)), the entry will be a
	      symbolic link with contents of the form

		  anon_inode:<file-type>

	      In some cases, the file-type is surrounded by square brackets.

	      For example, an epoll file descriptor will have a symbolic  link
	      whose content is the string anon_inode:[eventpoll].

	      In  a  multithreaded process, the contents of this directory are
	      not available if the main thread has already  terminated	(typi-
	      cally by calling pthread_exit(3)).

	      Programs	that  will take a filename as a command-line argument,
	      but will not take input from standard input if  no  argument  is
	      supplied,	 or that write to a file named as a command-line argu-
	      ment, but will not send their output to standard	output	if  no
	      argument	is  supplied, can nevertheless be made to use standard
	      input or standard out using /proc/[pid]/fd.  For example, assum-
	      ing  that -i is the flag designating an input file and -o is the
	      flag designating an output file:

		  $ foobar -i /proc/self/fd/0 -o /proc/self/fd/1 ...

	      and you have a working filter.

	      /proc/self/fd/N is approximately the same as /dev/fd/N  in  some
	      UNIX and UNIX-like systems.  Most Linux MAKEDEV scripts symboli-
	      cally link /dev/fd to /proc/self/fd, in fact.

	      Most systems provide symbolic links /dev/stdin, /dev/stdout, and
	      /dev/stderr, which respectively link to the files 0, 1, and 2 in
	      /proc/self/fd.  Thus the example command above could be  written
	      as:

		  $ foobar -i /dev/stdin -o /dev/stdout ...

       /proc/[pid]/fdinfo/ (since Linux 2.6.22)
	      This  is a subdirectory containing one entry for each file which
	      the process has open, named by its file descriptor.   The	 files
	      in this directory are readable only by the owner of the process.
	      The contents of each file can  be	 read  to  obtain  information
	      about the corresponding file descriptor.	The content depends on
	      the type of file referred to by the corresponding descriptor.

	      For regular files and directories, we see something like:

		  $ cat /proc/12015/fdinfo/4
		  pos:	  1000
		  flags:  01002002
		  mnt_id: 21

	      The pos field is a decimal number showing the current file  off-
	      set.   The flags field is an octal number that displays the file
	      access mode and file status flags	 (see  open(2)).   The	mnt_id
	      field,  present  since  Linux 3.15, is the ID of the mount point
	      containing    this    file.     See    the    description	    of
	      /proc/[pid]/mountinfo.

	      For  eventfd  file descriptors (see eventfd(2)), we see the fol-
	      lowing fields:

		  pos: 0
		  flags:    02
		  mnt_id:   10
		  eventfd-count:	       40

	      eventfd-count is the current value of the	 eventfd  counter,  in
	      hexadecimal.

	      For  epoll file descriptors (see epoll(7)), we see the following
	      fields:

		  pos: 0
		  flags:    02
		  mnt_id:   10
		  tfd:	      9 events:	      19 data: 74253d2500000009
		  tfd:	      7 events:	      19 data: 74253d2500000007

	      Each of the lines	 beginning  tfd	 describes  one	 of  the  file
	      descriptors  being  monitored via the epoll file descriptor (see
	      epoll_ctl(2) for some details).  The tfd field is the number  of
	      the  file descriptor.  The events field is a hexadecimal mask of
	      the events being monitored for this file descriptor.   The  data
	      field is the data value associated with this file descriptor.

	      For signalfd file descriptors (see signalfd(2)), we see the fol-
	      lowing fields:

		  pos: 0
		  flags:    02
		  mnt_id:   10
		  sigmask:  0000000000000006

	      sigmask is the hexadecimal mask of signals that are accepted via
	      this  signalfd  file descriptor.	(In this example, bits 2 and 3
	      are set, corresponding to the signals SIGINT  and	 SIGQUIT;  see
	      signal(7).)

       /proc/[pid]/io (since kernel 2.6.20)
	      This file contains I/O statistics for the process, for example:

		  # cat /proc/3828/io
		  rchar: 323934931
		  wchar: 323929600
		  syscr: 632687
		  syscw: 632675
		  read_bytes: 0
		  write_bytes: 323932160
		  cancelled_write_bytes: 0

	      The fields are as follows:

	      rchar: characters read
		     The number of bytes which this task has caused to be read
		     from storage.  This is simply the sum of bytes which this
		     process  passed  to read(2) and similar system calls.  It
		     includes things such as terminal I/O and is unaffected by
		     whether or not actual physical disk I/O was required (the
		     read might have been satisfied from pagecache).

	      wchar: characters written
		     The number of bytes which this task has caused, or	 shall
		     cause  to be written to disk.  Similar caveats apply here
		     as with rchar.

	      syscr: read syscalls
		     Attempt to count the number of read I/O  operations--that
		     is, system calls such as read(2) and pread(2).

	      syscw: write syscalls
		     Attempt to count the number of write I/O operations--that
		     is, system calls such as write(2) and pwrite(2).

	      read_bytes: bytes read
		     Attempt to count the number of bytes which	 this  process
		     really  did  cause	 to be fetched from the storage layer.
		     This is accurate for block-backed filesystems.

	      write_bytes: bytes written
		     Attempt to count the number of bytes which	 this  process
		     caused to be sent to the storage layer.

	      cancelled_write_bytes:
		     The big inaccuracy here is truncate.  If a process writes
		     1MB to a file and then deletes the file, it will in  fact
		     perform  no writeout.  But it will have been accounted as
		     having caused 1MB of write.  In other words:  this	 field
		     represents	 the number of bytes which this process caused
		     to not happen, by truncating pagecache.  A task can cause
		     "negative"	 I/O  too.   If this task truncates some dirty
		     pagecache, some I/O which another task has been accounted
		     for (in its write_bytes) will not be happening.

	      Note:  In	 the  current implementation, things are a bit racy on
	      32-bit systems: if process A reads  process  B's	/proc/[pid]/io
	      while  process  B	 is  updating  one  of	these 64-bit counters,
	      process A could see an intermediate result.

       /proc/[pid]/gid_map (since Linux 3.5)
	      See user_namespaces(7).

       /proc/[pid]/limits (since Linux 2.6.24)
	      This file displays the soft limit, hard limit, and units of mea-
	      surement	for  each  of the process's resource limits (see getr-
	      limit(2)).  Up to and including Linux 2.6.35, this file is  pro-
	      tected  to  allow	 reading  only by the real UID of the process.
	      Since Linux 2.6.36, this file is readable by all	users  on  the
	      system.

       /proc/[pid]/map_files/ (since kernel 3.3)
	      This  subdirectory  contains  entries  corresponding  to memory-
	      mapped files (see mmap(2)).  Entries are named by memory	region
	      start  and  end address pair (expressed as hexadecimal numbers),
	      and are symbolic links to the mapped files themselves.  Here  is
	      an example, with the output wrapped and reformatted to fit on an
	      80-column display:

		  # ls -l /proc/self/map_files/
		  lr--------. 1 root root 64 Apr 16 21:31
			      3252e00000-3252e20000 -> /usr/lib64/ld-2.15.so
		  ...

	      Although these entries are present for memory regions that  were
	      mapped  with  the MAP_FILE flag, the way anonymous shared memory
	      (regions created with the MAP_ANON | MAP_SHARED flags) is imple-
	      mented  in  Linux	 means	that  such regions also appear on this
	      directory.  Here is an example where  the	 target	 file  is  the
	      deleted /dev/zero one:


		  lrw-------. 1 root root 64 Apr 16 21:33
			      7fc075d2f000-7fc075e6f000 -> /dev/zero (deleted)

	      This  directory  appears	only  if the CONFIG_CHECKPOINT_RESTORE
	      kernel   configuration	option	  is	enabled.     Privilege
	      (CAP_SYS_ADMIN)  is required to view the contents of this direc-
	      tory.

       /proc/[pid]/maps
	      A file containing the currently mapped memory regions and	 their
	      access  permissions.   See  mmap(2) for some further information
	      about memory mappings.

	      The format of the file is:

       address		 perms offset  dev   inode	 pathname
       00400000-00452000 r-xp 00000000 08:02 173521	 /usr/bin/dbus-daemon
       00651000-00652000 r--p 00051000 08:02 173521	 /usr/bin/dbus-daemon
       00652000-00655000 rw-p 00052000 08:02 173521	 /usr/bin/dbus-daemon
       00e03000-00e24000 rw-p 00000000 00:00 0		 [heap]
       00e24000-011f7000 rw-p 00000000 00:00 0		 [heap]
       ...
       35b1800000-35b1820000 r-xp 00000000 08:02 135522	 /usr/lib64/ld-2.15.so
       35b1a1f000-35b1a20000 r--p 0001f000 08:02 135522	 /usr/lib64/ld-2.15.so
       35b1a20000-35b1a21000 rw-p 00020000 08:02 135522	 /usr/lib64/ld-2.15.so
       35b1a21000-35b1a22000 rw-p 00000000 00:00 0
       35b1c00000-35b1dac000 r-xp 00000000 08:02 135870	 /usr/lib64/libc-2.15.so
       35b1dac000-35b1fac000 ---p 001ac000 08:02 135870	 /usr/lib64/libc-2.15.so
       35b1fac000-35b1fb0000 r--p 001ac000 08:02 135870	 /usr/lib64/libc-2.15.so
       35b1fb0000-35b1fb2000 rw-p 001b0000 08:02 135870	 /usr/lib64/libc-2.15.so
       ...
       f2c6ff8c000-7f2c7078c000 rw-p 00000000 00:00 0	 [stack:986]
       ...
       7fffb2c0d000-7fffb2c2e000 rw-p 00000000 00:00 0	 [stack]
       7fffb2d48000-7fffb2d49000 r-xp 00000000 00:00 0	 [vdso]

	      The address field is the address space in the process  that  the
	      mapping occupies.	 The perms field is a set of permissions:

		   r = read
		   w = write
		   x = execute
		   s = shared
		   p = private (copy on write)

	      The  offset  field  is the offset into the file/whatever; dev is
	      the device (major:minor); inode is the inode on that device.   0
	      indicates that no inode is associated with the memory region, as
	      would be the case with BSS (uninitialized data).

	      The pathname field will usually be the file that is backing  the
	      mapping.	For ELF files, you can easily coordinate with the off-
	      set field by looking at the Offset  field	 in  the  ELF  program
	      headers (readelf -l).

	      There are additional helpful pseudo-paths:

		   [stack]
			  The  initial	process's  (also  known	 as  the  main
			  thread's) stack.

		   [stack:<tid>] (since Linux 3.4)
			  A thread's stack (where the <tid> is a  thread  ID).
			  It corresponds to the /proc/[pid]/task/[tid]/ path.

		   [vdso] The virtual dynamically linked shared object.

		   [heap] The process's heap.

	      If  the pathname field is blank, this is an anonymous mapping as
	      obtained via the mmap(2) function.  There	 is  no	 easy  way  to
	      coordinate  this back to a process's source, short of running it
	      through gdb(1), strace(1), or similar.

	      Under Linux 2.0, there is no field giving pathname.

       /proc/[pid]/mem
	      This file can be used to access the pages of a process's	memory
	      through open(2), read(2), and lseek(2).

       /proc/[pid]/mountinfo (since Linux 2.6.26)
	      This  file contains information about mount points.  It contains
	      lines of the form:

	      36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
	      (1)(2)(3)	  (4)	(5)	 (6)	  (7)	(8) (9)	  (10)	       (11)

	      The numbers in  parentheses  are	labels	for  the  descriptions
	      below:

	      (1)  mount  ID:  unique  identifier  of the mount (may be reused
		   after umount(2)).

	      (2)  parent ID: ID of parent mount (or of self for  the  top  of
		   the mount tree).

	      (3)  major:minor:	 value	of st_dev for files on filesystem (see
		   stat(2)).

	      (4)  root: root of the mount within the filesystem.

	      (5)  mount point: mount point relative to the process's root.

	      (6)  mount options: per-mount options.

	      (7)  optional  fields:  zero  or	more  fields   of   the	  form
		   "tag[:value]".

	      (8)  separator: marks the end of the optional fields.

	      (9)  filesystem type: name of filesystem in the form "type[.sub-
		   type]".

	      (10) mount source: filesystem-specific information or "none".

	      (11) super options: per-superblock options.

	      Parsers should ignore all unrecognized  optional	fields.	  Cur-
	      rently the possible optional fields are:

		   shared:X	     mount is shared in peer group X

		   master:X	     mount is slave to peer group X

		   propagate_from:X  mount  is	slave and receives propagation
				     from peer group X (*)

		   unbindable	     mount is unbindable

	      (*) X is the closest dominant peer  group	 under	the  process's
	      root.  If X is the immediate master of the mount, or if there is
	      no dominant peer group under the same root, then only the	 "mas-
	      ter:X" field is present and not the "propagate_from:X" field.

	      For  more	 information  on  mount	 propagation  see:  Documenta-
	      tion/filesystems/sharedsubtree.txt in the	 Linux	kernel	source
	      tree.

       /proc/[pid]/mounts (since Linux 2.4.19)
	      This  is	a list of all the filesystems currently mounted in the
	      process's mount namespace.  The format of	 this  file  is	 docu-
	      mented  in  fstab(5).  Since kernel version 2.6.15, this file is
	      pollable: after opening the file for reading, a change  in  this
	      file  (i.e.,  a filesystem mount or unmount) causes select(2) to
	      mark  the	 file  descriptor  as  readable,   and	 poll(2)   and
	      epoll_wait(2)  mark  the file as having an error condition.  See
	      namespaces(7) for more information.

       /proc/[pid]/mountstats (since Linux 2.6.17)
	      This file exports information (statistics, configuration	infor-
	      mation) about the mount points in the process's mount namespace.
	      Lines in this file have the form:

	      device /dev/sda7 mounted on /home with fstype ext3 [statistics]
	      (	      1	     )		  ( 2 )		    (3 ) (4)

	      The fields in each line are:

	      (1)  The name of the mounted device (or "nodevice" if  there  is
		   no corresponding device).

	      (2)  The mount point within the filesystem tree.

	      (3)  The filesystem type.

	      (4)  Optional  statistics	 and  configuration information.  Cur-
		   rently (as at Linux 2.6.26), only  NFS  filesystems	export
		   information via this field.

	      This file is readable only by the owner of the process.

	      See namespaces(7) for more information.

       /proc/[pid]/ns/ (since Linux 3.0)
	      This  is	a subdirectory containing one entry for each namespace
	      that supports being manipulated by setns(2).  For more  informa-
	      tion, see namespaces(7).


       /proc/[pid]/numa_maps (since Linux 2.6.14)
	      See numa(7).

       /proc/[pid]/oom_adj (since Linux 2.6.11)
	      This  file  can be used to adjust the score used to select which
	      process should be killed in an  out-of-memory  (OOM)  situation.
	      The  kernel  uses	 this  value  for a bit-shift operation of the
	      process's oom_score value: valid values are in the range -16  to
	      +15,  plus  the  special	value  -17, which disables OOM-killing
	      altogether for this process.  A  positive	 score	increases  the
	      likelihood  of  this  process  being killed by the OOM-killer; a
	      negative score decreases the likelihood.

	      The default value for this file is 0; a new process inherits its
	      parent's	 oom_adj   setting.   A	 process  must	be  privileged
	      (CAP_SYS_RESOURCE) to update this file.

	      Since Linux 2.6.36, use of this file is deprecated in  favor  of
	      /proc/[pid]/oom_score_adj.

       /proc/[pid]/oom_score (since Linux 2.6.11)
	      This  file  displays  the current score that the kernel gives to
	      this process for the purpose of selecting a process for the OOM-
	      killer.  A higher score means that the process is more likely to
	      be selected by the OOM-killer.  The basis for this score is  the
	      amount  of  memory  used	by  the process, with increases (+) or
	      decreases (-) for factors including:

	      * whether the process creates a lot of  children	using  fork(2)
		(+);

	      * whether	 the process has been running a long time, or has used
		a lot of CPU time (-);

	      * whether the process has a low nice value (i.e., > 0) (+);

	      * whether the process is privileged (-); and

	      * whether the process is making direct hardware access (-).

	      The oom_score also reflects  the	adjustment  specified  by  the
	      oom_score_adj or oom_adj setting for the process.

       /proc/[pid]/oom_score_adj (since Linux 2.6.36)
	      This  file  can  be used to adjust the badness heuristic used to
	      select which process gets killed in out-of-memory conditions.

	      The badness heuristic assigns a value  to	 each  candidate  task
	      ranging  from  0 (never kill) to 1000 (always kill) to determine
	      which process is targeted.  The units are roughly	 a  proportion
	      along  that  range  of  allowed  memory the process may allocate
	      from, based on an estimation of its current memory and swap use.
	      For  example, if a task is using all allowed memory, its badness
	      score will be 1000.  If it is using half of its allowed  memory,
	      its score will be 500.

	      There  is	 an  additional	 factor included in the badness score:
	      root processes are given 3% extra memory over other tasks.

	      The amount of "allowed" memory depends on the context  in	 which
	      the  OOM-killer was called.  If it is due to the memory assigned
	      to the allocating task's cpuset  being  exhausted,  the  allowed
	      memory  represents  the set of mems assigned to that cpuset (see
	      cpuset(7)).  If  it  is  due  to	a  mempolicy's	node(s)	 being
	      exhausted,  the  allowed	memory represents the set of mempolicy
	      nodes.  If it is due to a memory limit  (or  swap	 limit)	 being
	      reached,	the allowed memory is that configured limit.  Finally,
	      if it is due to the entire  system  being	 out  of  memory,  the
	      allowed memory represents all allocatable resources.

	      The  value of oom_score_adj is added to the badness score before
	      it is used to determine which task to kill.   Acceptable	values
	      range	from	 -1000	   (OOM_SCORE_ADJ_MIN)	   to	 +1000
	      (OOM_SCORE_ADJ_MAX).  This allows	 user  space  to  control  the
	      preference  for  OOM-killing,  ranging  from always preferring a
	      certain task or completely disabling it from OOM	killing.   The
	      lowest  possible	value,	-1000, is equivalent to disabling OOM-
	      killing entirely for that task, since it will  always  report  a
	      badness score of 0.

	      Consequently,  it	 is  very  simple for user space to define the
	      amount  of  memory  to  consider	for  each  task.   Setting   a
	      oom_score_adj  value of +500, for example, is roughly equivalent
	      to allowing the remainder of  tasks  sharing  the	 same  system,
	      cpuset,  mempolicy,  or  memory  controller  resources to use at
	      least 50% more memory.  A value of  -500,	 on  the  other	 hand,
	      would  be	 roughly  equivalent  to discounting 50% of the task's
	      allowed memory from being	 considered  as	 scoring  against  the
	      task.

	      For    backward	 compatibility	  with	  previous    kernels,
	      /proc/[pid]/oom_adj can still be used to tune the badness score.
	      Its value is scaled linearly with oom_score_adj.

	      Writing to /proc/[pid]/oom_score_adj or /proc/[pid]/oom_adj will
	      change the other with its scaled value.

       /proc/[pid]/pagemap (since Linux 2.6.25)
	      This file shows the mapping of each  of  the  process's  virtual
	      pages  into  physical page frames or swap area.  It contains one
	      64-bit value for each virtual page, with the bits	 set  as  fol-
	      lows:

		   63	  If set, the page is present in RAM.

		   62	  If set, the page is in swap space

		   61 (since Linux 3.5)
			  The page is a file-mapped page or a shared anonymous
			  page.

		   60-56 (since Linux 3.11)
			  Zero

		   55 (Since Linux 3.11)
			  PTE is soft-dirty (see the kernel source file	 Docu-
			  mentation/vm/soft-dirty.txt).

		   54-0	  If  the  page is present in RAM (bit 63), then these
			  bits provide the page frame  number,	which  can  be
			  used to index /proc/kpageflags and /proc/kpagecount.
			  If the page is present in swap (bit 62),  then  bits
			  4-0  give  the  swap	type, and bits 54-5 encode the
			  swap offset.

	      Before Linux 3.11, bits 60-55 were used to encode the base-2 log
	      of the page size.

	      To  employ /proc/[pid]/pagemap efficiently, use /proc/[pid]/maps
	      to determine which areas of memory are actually mapped and  seek
	      to skip over unmapped regions.

	      The  /proc/[pid]/pagemap	file  is  present  only	 if  the  CON-
	      FIG_PROC_PAGE_MONITOR kernel configuration option is enabled.

       /proc/[pid]/personality (since Linux 2.6.28)
	      This read-only file exposes the process's execution  domain,  as
	      set  by  personality(2).	 The value is displayed in hexadecimal
	      notation.

       /proc/[pid]/root
	      UNIX and Linux support the idea of a  per-process	 root  of  the
	      filesystem,  set	by  the chroot(2) system call.	This file is a
	      symbolic link that points to the process's root  directory,  and
	      behaves in the same way as exe, and fd/*.

	      In  a  multithreaded process, the contents of this symbolic link
	      are not available if the	main  thread  has  already  terminated
	      (typically by calling pthread_exit(3)).

       /proc/[pid]/seccomp (from Linux 2.6.12 to 2.6.22)
	      Read/set	the  seccomp  mode for the process.  If this file con-
	      tains the value zero, seccomp mode is not enabled.  Writing  the
	      value  1	to this file (irreversibly) places the process in sec-
	      comp  mode:  the	only  permitted	 system	 calls	are   read(2),
	      write(2),	 _exit(2),  and	 sigreturn(2).	This file went away in
	      Linux 2.6.23, when it was replaced by  a	prctl(2)-based	mecha-
	      nism.

       /proc/[pid]/setgroups (since Linux 3.19)
	      See user_namespaces(7).

       /proc/[pid]/smaps (since Linux 2.6.14)
	      This  file  shows	 memory	 consumption for each of the process's
	      mappings.	 (The pmap(1) command displays similar information, in
	      a	 form that may be easier for parsing.)	For each mapping there
	      is a series of lines such as the following:

		  00400000-0048a000 r-xp 00000000 fd:03 960637	     /bin/bash
		  Size:		       552 kB
		  Rss:		       460 kB
		  Pss:		       100 kB
		  Shared_Clean:	       452 kB
		  Shared_Dirty:		 0 kB
		  Private_Clean:	 8 kB
		  Private_Dirty:	 0 kB
		  Referenced:	       460 kB
		  Anonymous:		 0 kB
		  AnonHugePages:	 0 kB
		  Swap:			 0 kB
		  KernelPageSize:	 4 kB
		  MMUPageSize:		 4 kB
		  Locked:		 0 kB

	      The first of these lines shows the same information as  is  dis-
	      played for the mapping in /proc/[pid]/maps.  The remaining lines
	      show the size of the mapping, the amount of the mapping that  is
	      currently	 resident  in  RAM  ("Rss"), the process' proportional
	      share of this mapping ("Pss"), the number	 of  clean  and	 dirty
	      shared  pages  in the mapping, and the number of clean and dirty
	      private pages in the mapping.  "Referenced" indicates the amount
	      of  memory  currently marked as referenced or accessed.  "Anony-
	      mous" shows the amount of memory that does  not  belong  to  any
	      file.   "Swap"  shows how much would-be-anonymous memory is also
	      used, but out on swap.

	      The "KernelPageSize" entry is the page size used by  the	kernel
	      to  back	a  VMA.	  This matches the size used by the MMU in the
	      majority of cases.  However, one counter-example occurs on PPC64
	      kernels whereby a kernel using 64K as a base page size may still
	      use 4K pages for the MMU on older processors.   To  distinguish,
	      this  patch  reports  "MMUPageSize" as the page size used by the
	      MMU.

	      The "Locked" indicates whether the mapping is locked  in	memory
	      or not.

	      "VmFlags"	 field represents the kernel flags associated with the
	      particular virtual memory area in	 two  letter  encoded  manner.
	      The codes are the following:

		  rd  - readable
		  wr  - writable
		  ex  - executable
		  sh  - shared
		  mr  - may read
		  mw  - may write
		  me  - may execute
		  ms  - may share
		  gd  - stack segment grows down
		  pf  - pure PFN range
		  dw  - disabled write to the mapped file
		  lo  - pages are locked in memory
		  io  - memory mapped I/O area
		  sr  - sequential read advise provided
		  rr  - random read advise provided
		  dc  - do not copy area on fork
		  de  - do not expand area on remapping
		  ac  - area is accountable
		  nr  - swap space is not reserved for the area
		  ht  - area uses huge tlb pages
		  nl  - non-linear mapping
		  ar  - architecture specific flag
		  dd  - do not include area into core dump
		  sd  - soft-dirty flag
		  mm  - mixed map area
		  hg  - huge page advise flag
		  nh  - no-huge page advise flag
		  mg  - mergeable advise flag

	      The   /proc/[pid]/smaps	file  is  present  only	 if  the  CON-
	      FIG_PROC_PAGE_MONITOR kernel configuration option is enabled.

       /proc/[pid]/stack (since Linux 2.6.29)
	      This file provides a symbolic trace of  the  function  calls  in
	      this  process's kernel stack.  This file is provided only if the
	      kernel  was  built  with	the  CONFIG_STACKTRACE	 configuration
	      option.

       /proc/[pid]/stat
	      Status  information  about  the process.	This is used by ps(1).
	      It is defined in the kernel source file fs/proc/array.c.

	      The fields, in order, with their proper scanf(3)	format	speci-
	      fiers, are:

	      (1) pid  %d
			The process ID.

	      (2) comm	%s
			The  filename of the executable, in parentheses.  This
			is visible whether or not the  executable  is  swapped
			out.

	      (3) state	 %c
			One  of	 the  following characters, indicating process
			state:

			R  Running

			S  Sleeping in an interruptible wait

			D  Waiting in uninterruptible disk sleep

			Z  Zombie

			T  Stopped (on a  signal)  or  (before	Linux  2.6.33)
			   trace stopped

			t  Tracing stop (Linux 2.6.33 onward)

			W  Paging (only before Linux 2.6.0)

			X  Dead (from Linux 2.6.0 onward)

			x  Dead (Linux 2.6.33 to 3.13 only)

			K  Wakekill (Linux 2.6.33 to 3.13 only)

			W  Waking (Linux 2.6.33 to 3.13 only)

			P  Parked (Linux 3.9 to 3.13 only)

	      (4) ppid	%d
			The PID of the parent of this process.

	      (5) pgrp	%d
			The process group ID of the process.

	      (6) session  %d
			The session ID of the process.

	      (7) tty_nr  %d
			The  controlling  terminal of the process.  (The minor
			device number is contained in the combination of  bits
			31  to	20  and	 7 to 0; the major device number is in
			bits 15 to 8.)

	      (8) tpgid	 %d
			The ID of the foreground process group of the control-
			ling terminal of the process.

	      (9) flags	 %u
			The  kernel  flags word of the process.	 For bit mean-
			ings, see the PF_* defines in the Linux kernel	source
			file  include/linux/sched.h.   Details	depend	on the
			kernel version.

			The format for this field was %lu before Linux 2.6.

	      (10) minflt  %lu
			The number of minor faults the process has made	 which
			have not required loading a memory page from disk.

	      (11) cminflt  %lu
			The  number of minor faults that the process's waited-
			for children have made.

	      (12) majflt  %lu
			The number of major faults the process has made	 which
			have required loading a memory page from disk.

	      (13) cmajflt  %lu
			The  number of major faults that the process's waited-
			for children have made.

	      (14) utime  %lu
			Amount of time that this process has been scheduled in
			user   mode,   measured	 in  clock  ticks  (divide  by
			sysconf(_SC_CLK_TCK)).	 This  includes	 guest	 time,
			guest_time  (time  spent  running  a  virtual CPU, see
			below), so that applications that are not aware of the
			guest time field do not lose that time from their cal-
			culations.

	      (15) stime  %lu
			Amount of time that this process has been scheduled in
			kernel	mode,  measured	 in  clock  ticks  (divide  by
			sysconf(_SC_CLK_TCK)).

	      (16) cutime  %ld
			Amount of time that this process's waited-for children
			have  been  scheduled  in user mode, measured in clock
			ticks (divide  by  sysconf(_SC_CLK_TCK)).   (See  also
			times(2).)   This  includes  guest  time,  cguest_time
			(time spent running a virtual CPU, see below).

	      (17) cstime  %ld
			Amount of time that this process's waited-for children
			have  been scheduled in kernel mode, measured in clock
			ticks (divide by sysconf(_SC_CLK_TCK)).

	      (18) priority  %ld
			(Explanation for Linux 2.6) For	 processes  running  a
			real-time   scheduling	 policy	  (policy  below;  see
			sched_setscheduler(2)), this is the negated scheduling
			priority, minus one; that is, a number in the range -2
			to -100, corresponding to real-time  priorities	 1  to
			99.   For  processes  running  under  a	 non-real-time
			scheduling policy, this is the raw nice value (setpri-
			ority(2))  as  represented  in the kernel.  The kernel
			stores nice values as numbers in the range 0 (high) to
			39 (low), corresponding to the user-visible nice range
			of -20 to 19.

			Before Linux 2.6, this was a scaled value based on the
			scheduler weighting given to this process.

	      (19) nice	 %ld
			The  nice  value  (see setpriority(2)), a value in the
			range 19 (low priority) to -20 (high priority).

	      (20) num_threads	%ld
			Number of threads in this process (since  Linux	 2.6).
			Before kernel 2.6, this field was hard coded to 0 as a
			placeholder for an earlier removed field.

	      (21) itrealvalue	%ld
			The time in jiffies before the next SIGALRM is sent to
			the  process  due  to an interval timer.  Since kernel
			2.6.17, this field is no  longer  maintained,  and  is
			hard coded as 0.

	      (22) starttime  %llu
			The  time  the	process started after system boot.  In
			kernels before Linux 2.6, this value was expressed  in
			jiffies.   Since  Linux 2.6, the value is expressed in
			clock ticks (divide by sysconf(_SC_CLK_TCK)).

			The format for this field was %lu before Linux 2.6.

	      (23) vsize  %lu
			Virtual memory size in bytes.

	      (24) rss	%ld
			Resident Set Size: number of pages the process has  in
			real  memory.	This  is  just	the  pages which count
			toward text, data, or  stack  space.   This  does  not
			include pages which have not been demand-loaded in, or
			which are swapped out.

	      (25) rsslim  %lu
			Current soft limit in bytes on the rss of the process;
			see the description of RLIMIT_RSS in getrlimit(2).

	      (26) startcode  %lu
			The address above which program text can run.

	      (27) endcode  %lu
			The address below which program text can run.

	      (28) startstack  %lu
			The address of the start (i.e., bottom) of the stack.

	      (29) kstkesp  %lu
			The  current value of ESP (stack pointer), as found in
			the kernel stack page for the process.

	      (30) kstkeip  %lu
			The current EIP (instruction pointer).

	      (31) signal  %lu
			The bitmap of pending signals, displayed as a  decimal
			number.	  Obsolete, because it does not provide infor-
			mation on real-time  signals;  use  /proc/[pid]/status
			instead.

	      (32) blocked  %lu
			The  bitmap of blocked signals, displayed as a decimal
			number.	 Obsolete, because it does not provide	infor-
			mation	on  real-time  signals; use /proc/[pid]/status
			instead.

	      (33) sigignore  %lu
			The bitmap of ignored signals, displayed as a  decimal
			number.	  Obsolete, because it does not provide infor-
			mation on real-time  signals;  use  /proc/[pid]/status
			instead.

	      (34) sigcatch  %lu
			The  bitmap  of caught signals, displayed as a decimal
			number.	 Obsolete, because it does not provide	infor-
			mation	on  real-time  signals; use /proc/[pid]/status
			instead.

	      (35) wchan  %lu
			This is the "channel" in which the process is waiting.
			It  is	the  address of a location in the kernel where
			the process is sleeping.  The  corresponding  symbolic
			name can be found in /proc/[pid]/wchan.

	      (36) nswap  %lu
			Number of pages swapped (not maintained).

	      (37) cnswap  %lu
			Cumulative nswap for child processes (not maintained).

	      (38) exit_signal	%d  (since Linux 2.1.22)
			Signal to be sent to parent when we die.

	      (39) processor  %d  (since Linux 2.2.8)
			CPU number last executed on.

	      (40) rt_priority	%u  (since Linux 2.5.19)
			Real-time scheduling priority, a number in the range 1
			to 99 for processes scheduled under a  real-time  pol-
			icy,   or   0,	 for   non-real-time   processes  (see
			sched_setscheduler(2)).

	      (41) policy  %u  (since Linux 2.5.19)
			Scheduling policy (see sched_setscheduler(2)).	Decode
			using the SCHED_* constants in linux/sched.h.

			The format for this field was %lu before Linux 2.6.22.

	      (42) delayacct_blkio_ticks  %llu	(since Linux 2.6.18)
			Aggregated  block  I/O delays, measured in clock ticks
			(centiseconds).

	      (43) guest_time  %lu  (since Linux 2.6.24)
			Guest time of the process (time spent running  a  vir-
			tual  CPU  for	a guest operating system), measured in
			clock ticks (divide by sysconf(_SC_CLK_TCK)).

	      (44) cguest_time	%ld  (since Linux 2.6.24)
			Guest time of  the  process's  children,  measured  in
			clock ticks (divide by sysconf(_SC_CLK_TCK)).

	      (45) start_data  %lu  (since Linux 3.3)
			Address above which program initialized and uninitial-
			ized (BSS) data are placed.

	      (46) end_data  %lu  (since Linux 3.3)
			Address below which program initialized and uninitial-
			ized (BSS) data are placed.

	      (47) start_brk  %lu  (since Linux 3.3)
			Address	 above which program heap can be expanded with
			brk(2).

	      (48) arg_start  %lu  (since Linux 3.5)
			Address above  which  program  command-line  arguments
			(argv) are placed.

	      (49) arg_end  %lu	 (since Linux 3.5)
			Address	 below	program	 command-line arguments (argv)
			are placed.

	      (50) env_start  %lu  (since Linux 3.5)
			Address above which program environment is placed.

	      (51) env_end  %lu	 (since Linux 3.5)
			Address below which program environment is placed.

	      (52) exit_code  %d  (since Linux 3.5)
			The thread's exit status in the form reported by wait-
			pid(2).

       /proc/[pid]/statm
	      Provides information about memory usage, measured in pages.  The
	      columns are:

		  size	     (1) total program size
			     (same as VmSize in /proc/[pid]/status)
		  resident   (2) resident set size
			     (same as VmRSS in /proc/[pid]/status)
		  share	     (3) shared pages (i.e., backed by a file)
		  text	     (4) text (code)
		  lib	     (5) library (unused in Linux 2.6)
		  data	     (6) data + stack
		  dt	     (7) dirty pages (unused in Linux 2.6)

       /proc/[pid]/status
	      Provides	much  of  the  information  in	/proc/[pid]/stat   and
	      /proc/[pid]/statm in a format that's easier for humans to parse.
	      Here's an example:

		  $ cat /proc/$$/status
		  Name:	  bash
		  State:  S (sleeping)
		  Tgid:	  3515
		  Pid:	  3515
		  PPid:	  3452
		  TracerPid:	  0
		  Uid:	  1000	  1000	  1000	  1000
		  Gid:	  100	  100	  100	  100
		  FDSize: 256
		  Groups: 16 33 100
		  VmPeak:     9136 kB
		  VmSize:     7896 kB
		  VmLck:	 0 kB
		  VmPin:	 0 kB
		  VmHWM:      7572 kB
		  VmRSS:      6316 kB
		  VmData:     5224 kB
		  VmStk:	88 kB
		  VmExe:       572 kB
		  VmLib:      1708 kB
		  VmPMD:	 4 kB
		  VmPTE:	20 kB
		  VmSwap:	 0 kB
		  Threads:	  1
		  SigQ:	  0/3067
		  SigPnd: 0000000000000000
		  ShdPnd: 0000000000000000
		  SigBlk: 0000000000010000
		  SigIgn: 0000000000384004
		  SigCgt: 000000004b813efb
		  CapInh: 0000000000000000
		  CapPrm: 0000000000000000
		  CapEff: 0000000000000000
		  CapBnd: ffffffffffffffff
		  CapAmb:   0000000000000000
		  Seccomp:	  0
		  Cpus_allowed:	  00000001
		  Cpus_allowed_list:	  0
		  Mems_allowed:	  1
		  Mems_allowed_list:	  0
		  voluntary_ctxt_switches:	  150
		  nonvoluntary_ctxt_switches:	  545

	      The fields are as follows:

	      * Name: Command run by this process.

	      * State: Current state of the process.  One of "R (running)", "S
		(sleeping)",  "D  (disk	 sleep)",  "T  (stopped)", "T (tracing
		stop)", "Z (zombie)", or "X (dead)".

	      * Tgid: Thread group ID (i.e., Process ID).

	      * Pid: Thread ID (see gettid(2)).

	      * PPid: PID of parent process.

	      * TracerPid: PID of process tracing this process (0 if not being
		traced).

	      * Uid,  Gid:  Real,  effective,  saved  set, and filesystem UIDs
		(GIDs).

	      * FDSize: Number of file descriptor slots currently allocated.

	      * Groups: Supplementary group list.

	      * VmPeak: Peak virtual memory size.

	      * VmSize: Virtual memory size.

	      * VmLck: Locked memory size (see mlock(3)).

	      * VmPin: Pinned memory size (since Linux 3.2).  These are	 pages
		that can't be moved because something needs to directly access
		physical memory.

	      * VmHWM: Peak resident set size ("high water mark").

	      * VmRSS: Resident set size.

	      * VmData, VmStk, VmExe: Size of data, stack, and text segments.

	      * VmLib: Shared library code size.

	      * VmPTE: Page table entries size (since Linux 2.6.10).

	      * VmPMD: Size of second-level page tables (since Linux 4.0).

	      * VmSwap: Swapped-out virtual memory size by  anonymous  private
		pages; shmem swap usage is not included (since Linux 2.6.34).

	      * Threads: Number of threads in process containing this thread.

	      * SigQ:  This  field  contains  two slash-separated numbers that
		relate to queued signals for the real user ID of this process.
		The  first  of these is the number of currently queued signals
		for this real user ID, and the second is the resource limit on
		the  number  of	 queued	 signals  for  this  process  (see the
		description of RLIMIT_SIGPENDING in getrlimit(2)).

	      * SigPnd, ShdPnd: Number of signals pending for thread  and  for
		process as a whole (see pthreads(7) and signal(7)).

	      * SigBlk,	  SigIgn,   SigCgt:  Masks  indicating	signals	 being
		blocked, ignored, and caught (see signal(7)).

	      * CapInh, CapPrm,	 CapEff:  Masks	 of  capabilities  enabled  in
		inheritable,  permitted,  and  effective  sets	(see capabili-
		ties(7)).

	      * CapBnd: Capability Bounding set (since Linux 2.6.26, see capa-
		bilities(7)).

	      * CapAmb: Ambient capability set (since Linux 4.3, see capabili-
		ties(7)).

	      * Seccomp: Seccomp mode of the process  (since  Linux  3.8,  see
		seccomp(2)).   0  means	 SECCOMP_MODE_DISABLED;	 1  means SEC-
		COMP_MODE_STRICT; 2 means SECCOMP_MODE_FILTER.	This field  is
		provided  only if the kernel was built with the CONFIG_SECCOMP
		kernel configuration option enabled.

	      * Cpus_allowed: Mask of CPUs  on	which  this  process  may  run
		(since Linux 2.6.24, see cpuset(7)).

	      * Cpus_allowed_list:  Same  as  previous,	 but  in "list format"
		(since Linux 2.6.26, see cpuset(7)).

	      * Mems_allowed: Mask of memory nodes  allowed  to	 this  process
		(since Linux 2.6.24, see cpuset(7)).

	      * Mems_allowed_list:  Same  as  previous,	 but  in "list format"
		(since Linux 2.6.26, see cpuset(7)).

	      * voluntary_ctxt_switches, nonvoluntary_ctxt_switches: Number of
		voluntary   and	 involuntary  context  switches	 (since	 Linux
		2.6.23).

       /proc/[pid]/syscall (since Linux 2.6.27)
	      This file exposes the system call number and argument  registers
	      for  the	system	call  currently being executed by the process,
	      followed by the values of the stack pointer and program  counter
	      registers.   The	values	of  all	 six  argument	registers  are
	      exposed, although most system calls use fewer registers.

	      If the process is blocked, but not in a system  call,  then  the
	      file displays -1 in place of the system call number, followed by
	      just the values of the stack pointer and	program	 counter.   If
	      process  is  not blocked, then the file contains just the string
	      "running".

	      This file is present only if the kernel was configured with CON-
	      FIG_HAVE_ARCH_TRACEHOOK.

       /proc/[pid]/task (since Linux 2.6.0-test6)
	      This  is	a  directory  that  contains one subdirectory for each
	      thread in the process.  The name of  each	 subdirectory  is  the
	      numerical	 thread	 ID  ([tid])  of  the  thread (see gettid(2)).
	      Within each of these subdirectories, there is  a	set  of	 files
	      with the same names and contents as under the /proc/[pid] direc-
	      tories.  For attributes that are shared by all threads, the con-
	      tents  for each of the files under the task/[tid] subdirectories
	      will be the same as in the  corresponding	 file  in  the	parent
	      /proc/[pid]  directory (e.g., in a multithreaded process, all of
	      the task/[tid]/cwd  files	 will  have  the  same	value  as  the
	      /proc/[pid]/cwd  file  in the parent directory, since all of the
	      threads in a process share a working directory).	For attributes
	      that are distinct for each thread, the corresponding files under
	      task/[tid] may have different values (e.g.,  various  fields  in
	      each  of	the  task/[tid]/status files may be different for each
	      thread).

	      In a multithreaded process, the contents of the /proc/[pid]/task
	      directory	 are not available if the main thread has already ter-
	      minated (typically by calling pthread_exit(3)).

       /proc/[pid]/timers (since Linux 3.10)
	      A list of the POSIX timers for  this  process.   Each  timer  is
	      listed with a line that starts with the string "ID:".  For exam-
	      ple:

		  ID: 1
		  signal: 60/00007fff86e452a8
		  notify: signal/pid.2634
		  ClockID: 0
		  ID: 0
		  signal: 60/00007fff86e452a8
		  notify: signal/pid.2634
		  ClockID: 1

	      The lines shown for each timer have the following meanings:

	      ID     The ID for this timer.  This is not the same as the timer
		     ID	 returned  by  timer_create(2); rather, it is the same
		     kernel-internal ID that is available via  the  si_timerid
		     field of the siginfo_t structure (see sigaction(2)).

	      signal This is the signal number that this timer uses to deliver
		     notifications  followed  by  a  slash,   and   then   the
		     sigev_value  value supplied to the signal handler.	 Valid
		     only for timers that notify via a signal.

	      notify The part before the slash specifies  the  mechanism  that
		     this  timer  uses to deliver notifications, and is one of
		     "thread", "signal", or "none".  Immediately following the
		     slash   is	 either	 the  string  "tid"  for  timers  with
		     SIGEV_THREAD_ID notification, or "pid"  for  timers  that
		     notify by other mechanisms.  Following the "." is the PID
		     of the process (or the kernel thread ID  of  the  thread)
		     that  will	 be  delivered	a signal if the timer delivers
		     notifications via a signal.

	      ClockID
		     This field identifies the clock that the timer  uses  for
		     measuring	time.	For most clocks, this is a number that
		     matches one of the user-space CLOCK_*  constants  exposed
		     via  <time.h>.   CLOCK_PROCESS_CPUTIME_ID	timers display
		     with    a	  value	   of	 -6	in     this	field.
		     CLOCK_THREAD_CPUTIME_ID timers display with a value of -2
		     in this field.

	      This file is available only when the kernel was configured  with
	      CONFIG_CHECKPOINT_RESTORE.

       /proc/[pid]/uid_map, /proc/[pid]/gid_map (since Linux 3.5)
	      See user_namespaces(7).

       /proc/[pid]/wchan (since Linux 2.6.0)
	      The  symbolic  name  corresponding to the location in the kernel
	      where the process is sleeping.

       /proc/apm
	      Advanced power management version and battery  information  when
	      CONFIG_APM is defined at kernel compilation time.

       /proc/buddyinfo
	      This file contains information which is used for diagnosing mem-
	      ory fragmentation issues.	 Each line starts with the identifica-
	      tion  of	the node and the name of the zone which together iden-
	      tify a memory region This is  then  followed  by	the  count  of
	      available	 chunks	 of  a	certain order in which these zones are
	      split.  The size in bytes of a certain order  is	given  by  the
	      formula:

		  (2^order) * PAGE_SIZE

	      The  binary  buddy  allocator  algorithm	inside the kernel will
	      split one chunk into two chunks of a smaller  order  (thus  with
	      half  the size) or combine two contiguous chunks into one larger
	      chunk of a higher order (thus with double the size)  to  satisfy
	      allocation  requests  and	 to counter memory fragmentation.  The
	      order matches the column number, when starting to count at zero.

	      For example on a x86_64 system:

  Node 0, zone	   DMA	   1	1    1	  0    2    1	 1    0	   1	1    3
  Node 0, zone	 DMA32	  65   47    4	 81   52   28	13   10	   5	1  404
  Node 0, zone	Normal	 216   55  189	101   84   38	37   27	   5	3  587

	      In this example, there is one node containing  three  zones  and
	      there are 11 different chunk sizes.  If the page size is 4 kilo-
	      bytes, then the first zone called	 DMA  (on  x86	the  first  16
	      megabyte	of memory) has 1 chunk of 4 kilobytes (order 0) avail-
	      able and has 3 chunks of 4 megabytes (order 10) available.

	      If the memory is heavily fragmented,  the	 counters  for	higher
	      order  chunks  will  be  zero and allocation of large contiguous
	      areas will fail.

	      Further information about the zones can be found in  /proc/zone-
	      info.

       /proc/bus
	      Contains subdirectories for installed busses.

       /proc/bus/pccard
	      Subdirectory  for	 PCMCIA	 devices  when CONFIG_PCMCIA is set at
	      kernel compilation time.

       /proc/bus/pccard/drivers

       /proc/bus/pci
	      Contains various bus subdirectories and pseudo-files  containing
	      information  about  PCI  busses,	installed  devices, and device
	      drivers.	Some of these files are not ASCII.

       /proc/bus/pci/devices
	      Information about PCI devices.  They  may	 be  accessed  through
	      lspci(8) and setpci(8).

       /proc/cmdline
	      Arguments	 passed	 to the Linux kernel at boot time.  Often done
	      via a boot manager such as lilo(8) or grub(8).

       /proc/config.gz (since Linux 2.6)
	      This file exposes the configuration options that	were  used  to
	      build  the  currently running kernel, in the same format as they
	      would be shown in the .config file that resulted when  configur-
	      ing  the	kernel	(using make xconfig, make config, or similar).
	      The file contents are compressed;	 view  or  search  them	 using
	      zcat(1)  and  zgrep(1).  As long as no changes have been made to
	      the following file, the contents of /proc/config.gz are the same
	      as those provided by :

		  cat /lib/modules/$(uname -r)/build/.config

	      /proc/config.gz  is  provided  only  if the kernel is configured
	      with CONFIG_IKCONFIG_PROC.

       /proc/crypto
	      A list of the ciphers provided by the kernel  crypto  API.   For
	      details,	see  the  kernel Linux Kernel Crypto API documentation
	      available under the kernel source	 directory  Documentation/Doc-
	      Book.   (That documentation can be built using a command such as
	      make htmldocs in the root directory of the kernel source tree.)

       /proc/cpuinfo
	      This is a collection of CPU and  system  architecture  dependent
	      items,  for  each	 supported architecture a different list.  Two
	      common  entries  are  processor  which  gives  CPU  number   and
	      bogomips;	 a  system  constant  that is calculated during kernel
	      initialization.  SMP machines have  information  for  each  CPU.
	      The lscpu(1) command gathers its information from this file.

       /proc/devices
	      Text  listing  of	 major numbers and device groups.  This can be
	      used by MAKEDEV scripts for consistency with the kernel.

       /proc/diskstats (since Linux 2.5.69)
	      This file contains disk I/O statistics  for  each	 disk  device.
	      See  the	Linux kernel source file Documentation/iostats.txt for
	      further information.

       /proc/dma
	      This is a list of the registered ISA DMA (direct memory  access)
	      channels in use.

       /proc/driver
	      Empty subdirectory.

       /proc/execdomains
	      List of the execution domains (ABI personalities).

       /proc/fb
	      Frame buffer information when CONFIG_FB is defined during kernel
	      compilation.

       /proc/filesystems
	      A text listing of the filesystems which  are  supported  by  the
	      kernel,  namely  filesystems which were compiled into the kernel
	      or  whose	 kernel	 modules  are  currently  loaded.   (See  also
	      filesystems(5).)	 If  a filesystem is marked with "nodev", this
	      means that it does not require a	block  device  to  be  mounted
	      (e.g., virtual filesystem, network filesystem).

	      Incidentally, this file may be used by mount(8) when no filesys-
	      tem is specified and it didn't manage to determine the  filesys-
	      tem  type.   Then	 filesystems  contained in this file are tried
	      (excepted those that are marked with "nodev").

       /proc/fs
	      Contains subdirectories that in turn contain files with informa-
	      tion about (certain) mounted filesystems.

       /proc/ide
	      This  directory  exists  on systems with the IDE bus.  There are
	      directories for each IDE channel	and  attached  device.	 Files
	      include:

		  cache		     buffer size in KB
		  capacity	     number of sectors
		  driver	     driver version
		  geometry	     physical and logical geometry
		  identify	     in hexadecimal
		  media		     media type
		  model		     manufacturer's model number
		  settings	     drive settings
		  smart_thresholds   in hexadecimal
		  smart_values	     in hexadecimal

	      The  hdparm(8)  utility provides access to this information in a
	      friendly format.

       /proc/interrupts
	      This is used to record the number of interrupts per CPU  per  IO
	      device.	Since  Linux 2.6.24, for the i386 and x86_64 architec-
	      tures, at least, this also includes interrupts internal  to  the
	      system  (that is, not associated with a device as such), such as
	      NMI (nonmaskable interrupt), LOC (local  timer  interrupt),  and
	      for  SMP	systems,  TLB (TLB flush interrupt), RES (rescheduling
	      interrupt), CAL (remote function call interrupt),	 and  possibly
	      others.  Very easy to read formatting, done in ASCII.

       /proc/iomem
	      I/O memory map in Linux 2.4.

       /proc/ioports
	      This is a list of currently registered Input-Output port regions
	      that are in use.

       /proc/kallsyms (since Linux 2.5.71)
	      This holds the kernel exported symbol definitions	 used  by  the
	      modules(X)  tools to dynamically link and bind loadable modules.
	      In Linux 2.5.47 and earlier, a similar file with	slightly  dif-
	      ferent syntax was named ksyms.

       /proc/kcore
	      This  file  represents  the physical memory of the system and is
	      stored in the ELF core file format.  With this pseudo-file,  and
	      an unstripped kernel (/usr/src/linux/vmlinux) binary, GDB can be
	      used to examine the current state of any kernel data structures.

	      The total length of the file is  the  size  of  physical	memory
	      (RAM) plus 4KB.

       /proc/kmsg
	      This  file  can  be used instead of the syslog(2) system call to
	      read kernel messages.  A process must have superuser  privileges
	      to  read	this file, and only one process should read this file.
	      This file should not be read if  a  syslog  process  is  running
	      which uses the syslog(2) system call facility to log kernel mes-
	      sages.

	      Information in this file is retrieved with the dmesg(1) program.

       /proc/kpagecount (since Linux 2.6.25)
	      This file contains a 64-bit count of the number  of  times  each
	      physical page frame is mapped, indexed by page frame number (see
	      the discussion of /proc/[pid]/pagemap).

	      The  /proc/kpagecount  file  is  present	only   if   the	  CON-
	      FIG_PROC_PAGE_MONITOR kernel configuration option is enabled.

       /proc/kpageflags (since Linux 2.6.25)
	      This  file  contains 64-bit masks corresponding to each physical
	      page frame; it is indexed by page frame number (see the  discus-
	      sion of /proc/[pid]/pagemap).  The bits are as follows:

		   0 - KPF_LOCKED
		   1 - KPF_ERROR
		   2 - KPF_REFERENCED
		   3 - KPF_UPTODATE
		   4 - KPF_DIRTY
		   5 - KPF_LRU
		   6 - KPF_ACTIVE
		   7 - KPF_SLAB
		   8 - KPF_WRITEBACK
		   9 - KPF_RECLAIM
		  10 - KPF_BUDDY
		  11 - KPF_MMAP		  (since Linux 2.6.31)
		  12 - KPF_ANON		  (since Linux 2.6.31)
		  13 - KPF_SWAPCACHE	  (since Linux 2.6.31)
		  14 - KPF_SWAPBACKED	  (since Linux 2.6.31)
		  15 - KPF_COMPOUND_HEAD  (since Linux 2.6.31)
		  16 - KPF_COMPOUND_TAIL  (since Linux 2.6.31)
		  16 - KPF_HUGE		  (since Linux 2.6.31)
		  18 - KPF_UNEVICTABLE	  (since Linux 2.6.31)
		  19 - KPF_HWPOISON	  (since Linux 2.6.31)
		  20 - KPF_NOPAGE	  (since Linux 2.6.31)
		  21 - KPF_KSM		  (since Linux 2.6.32)
		  22 - KPF_THP		  (since Linux 3.4)

	      For  further details on the meanings of these bits, see the ker-
	      nel source  file	Documentation/vm/pagemap.txt.	Before	kernel
	      2.6.29,  KPF_WRITEBACK,  KPF_RECLAIM,  KPF_BUDDY, and KPF_LOCKED
	      did not report correctly.

	      The  /proc/kpageflags  file  is  present	only   if   the	  CON-
	      FIG_PROC_PAGE_MONITOR kernel configuration option is enabled.

       /proc/ksyms (Linux 1.1.23-2.5.47)
	      See /proc/kallsyms.

       /proc/loadavg
	      The  first  three	 fields	 in this file are load average figures
	      giving the number of jobs in the run queue (state R) or  waiting
	      for disk I/O (state D) averaged over 1, 5, and 15 minutes.  They
	      are the same as the load average numbers given by uptime(1)  and
	      other  programs.	The fourth field consists of two numbers sepa-
	      rated by a slash (/).  The first of these is the number of  cur-
	      rently runnable kernel scheduling entities (processes, threads).
	      The value after the slash is the	number	of  kernel  scheduling
	      entities that currently exist on the system.  The fifth field is
	      the PID of the process that was most  recently  created  on  the
	      system.

       /proc/locks
	      This  file  shows current file locks (flock(2) and fcntl(2)) and
	      leases (fcntl(2)).

       /proc/malloc (only up to and including Linux 2.2)
	      This file is present only	 if  CONFIG_DEBUG_MALLOC  was  defined
	      during compilation.

       /proc/meminfo
	      This  file  reports statistics about memory usage on the system.
	      It is used by free(1) to report the amount of free and used mem-
	      ory (both physical and swap) on the system as well as the shared
	      memory and buffers used by the kernel.  Each line	 of  the  file
	      consists	of a parameter name, followed by a colon, the value of
	      the parameter, and an option unit of measurement	(e.g.,	"kB").
	      The  list	 below	describes  the	parameter names and the format
	      specifier required to read the field  value.   Except  as	 noted
	      below,  all of the fields have been present since at least Linux
	      2.6.0.  Some fields are displayed only if the kernel was config-
	      ured  with  various options; those dependencies are noted in the
	      list.

	      MemTotal %lu
		     Total usable RAM (i.e., physical RAM minus a few reserved
		     bits and the kernel binary code).

	      MemFree %lu
		     The sum of LowFree+HighFree.

	      Buffers %lu
		     Relatively	 temporary  storage  for  raw disk blocks that
		     shouldn't get tremendously large (20MB or so).

	      Cached %lu
		     In-memory cache for files read from the  disk  (the  page
		     cache).  Doesn't include SwapCached.

	      SwapCached %lu
		     Memory  that once was swapped out, is swapped back in but
		     still also is in the swap file.  (If memory  pressure  is
		     high,  these  pages  don't	 need  to be swapped out again
		     because they are already in the swap  file.   This	 saves
		     I/O.)

	      Active %lu
		     Memory  that  has been used more recently and usually not
		     reclaimed unless absolutely necessary.

	      Inactive %lu
		     Memory which has been less recently  used.	  It  is  more
		     eligible to be reclaimed for other purposes.

	      Active(anon) %lu (since Linux 2.6.28)
		     [To be documented.]

	      Inactive(anon) %lu (since Linux 2.6.28)
		     [To be documented.]

	      Active(file) %lu (since Linux 2.6.28)
		     [To be documented.]

	      Inactive(file) %lu (since Linux 2.6.28)
		     [To be documented.]

	      Unevictable %lu (since Linux 2.6.28)
		     (From  Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU was
		     required.)	 [To be documented.]

	      Mlocked %lu (since Linux 2.6.28)
		     (From Linux 2.6.28 to 2.6.30, CONFIG_UNEVICTABLE_LRU  was
		     required.)	 [To be documented.]

	      HighTotal %lu
		     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
		     Total amount of highmem.  Highmem	is  all	 memory	 above
		     ~860MB  of physical memory.  Highmem areas are for use by
		     user-space programs, or for the page cache.   The	kernel
		     must  use	tricks to access this memory, making it slower
		     to access than lowmem.

	      HighFree %lu
		     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
		     Amount of free highmem.

	      LowTotal %lu
		     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
		     Total amount of lowmem.  Lowmem is memory	which  can  be
		     used  for everything that highmem can be used for, but it
		     is also available for the kernel's use for its  own  data
		     structures.   Among many other things, it is where every-
		     thing from Slab is allocated.   Bad  things  happen  when
		     you're out of lowmem.

	      LowFree %lu
		     (Starting with Linux 2.6.19, CONFIG_HIGHMEM is required.)
		     Amount of free lowmem.

	      MmapCopy %lu (since Linux 2.6.29)
		     (CONFIG_MMU is required.)	[To be documented.]

	      SwapTotal %lu
		     Total amount of swap space available.

	      SwapFree %lu
		     Amount of swap space that is currently unused.

	      Dirty %lu
		     Memory which is waiting to get written back to the disk.

	      Writeback %lu
		     Memory which is actively being written back to the disk.

	      AnonPages %lu (since Linux 2.6.18)
		     Non-file backed pages mapped into user-space page tables.

	      Mapped %lu
		     Files which have been mapped into memory (with  mmap(2)),
		     such as libraries.

	      Shmem %lu (since Linux 2.6.32)
		     [To be documented.]

	      Slab %lu
		     In-kernel data structures cache.

	      SReclaimable %lu (since Linux 2.6.19)
		     Part of Slab, that might be reclaimed, such as caches.

	      SUnreclaim %lu (since Linux 2.6.19)
		     Part  of  Slab,  that cannot be reclaimed on memory pres-
		     sure.

	      KernelStack %lu (since Linux 2.6.32)
		     Amount of memory allocated to kernel stacks.

	      PageTables %lu (since Linux 2.6.18)
		     Amount of memory dedicated to the lowest  level  of  page
		     tables.

	      Quicklists %lu (since Linux 2.6.27)
		     (CONFIG_QUICKLIST is required.)  [To be documented.]

	      NFS_Unstable %lu (since Linux 2.6.18)
		     NFS  pages	 sent  to the server, but not yet committed to
		     stable storage.

	      Bounce %lu (since Linux 2.6.18)
		     Memory used for block device "bounce buffers".

	      WritebackTmp %lu (since Linux 2.6.26)
		     Memory used by FUSE for temporary writeback buffers.

	      CommitLimit %lu (since Linux 2.6.10)
		     This is the total amount of memory currently available to
		     be allocated on the system, expressed in kilobytes.  This
		     limit is adhered to only if strict overcommit  accounting
		     is	 enabled  (mode	 2 in /proc/sys/vm/overcommit_memory).
		     The  limit	 is  calculated	 according  to	 the   formula
		     described under /proc/sys/vm/overcommit_memory.  For fur-
		     ther details,  see	 the  kernel  source  file  Documenta-
		     tion/vm/overcommit-accounting.

	      Committed_AS %lu
		     The  amount  of memory presently allocated on the system.
		     The committed memory is a sum of all of the memory	 which
		     has  been allocated by processes, even if it has not been
		     "used" by them as of yet.	A process which allocates  1GB
		     of	 memory (using malloc(3) or similar), but touches only
		     300MB of that memory will show up as using only 300MB  of
		     memory even if it has the address space allocated for the
		     entire 1GB.

		     This 1GB is memory which has been "committed" to  by  the
		     VM and can be used at any time by the allocating applica-
		     tion.  With strict overcommit enabled on the system (mode
		     2	in  IR	/proc/sys/vm/overcommit_memory	), allocations
		     which would exceed the CommitLimit will not be permitted.
		     This  is  useful if one needs to guarantee that processes
		     will not fail due to lack of memory once that memory  has
		     been successfully allocated.

	      VmallocTotal %lu
		     Total size of vmalloc memory area.

	      VmallocUsed %lu
		     Amount of vmalloc area which is used.

	      VmallocChunk %lu
		     Largest contiguous block of vmalloc area which is free.

	      HardwareCorrupted %lu (since Linux 2.6.32)
		     (CONFIG_MEMORY_FAILURE is required.)  [To be documented.]

	      AnonHugePages %lu (since Linux 2.6.38)
		     (CONFIG_TRANSPARENT_HUGEPAGE   is	 required.)   Non-file
		     backed huge pages mapped into user-space page tables.

	      HugePages_Total %lu
		     (CONFIG_HUGETLB_PAGE is required.)	 The size of the  pool
		     of huge pages.

	      HugePages_Free %lu
		     (CONFIG_HUGETLB_PAGE  is  required.)   The number of huge
		     pages in the pool that are not yet allocated.

	      HugePages_Rsvd %lu (since Linux 2.6.17)
		     (CONFIG_HUGETLB_PAGE is required.)	 This is the number of
		     huge  pages  for  which a commitment to allocate from the
		     pool has been made, but no allocation has yet been	 made.
		     These  reserved  huge pages guarantee that an application
		     will be able to allocate a huge page  from	 the  pool  of
		     huge pages at fault time.

	      HugePages_Surp %lu (since Linux 2.6.24)
		     (CONFIG_HUGETLB_PAGE is required.)	 This is the number of
		     huge   pages   in	 the   pool   above   the   value   in
		     /proc/sys/vm/nr_hugepages.	 The maximum number of surplus
		     huge  pages  is  controlled  by  /proc/sys/vm/nr_overcom-
		     mit_hugepages.

	      Hugepagesize %lu
		     (CONFIG_HUGETLB_PAGE  is  required.)   The	 size  of huge
		     pages.

       /proc/modules
	      A text list of the modules that have been loaded by the  system.
	      See also lsmod(8).

       /proc/mounts
	      Before  kernel  2.4.19, this file was a list of all the filesys-
	      tems currently mounted on the system.  With the introduction  of
	      per-process mount namespaces in Linux 2.4.19, this file became a
	      link to /proc/self/mounts, which lists the mount points  of  the
	      process's own mount namespace.  The format of this file is docu-
	      mented in fstab(5).

       /proc/mtrr
	      Memory Type Range Registers.  See the Linux kernel  source  file
	      Documentation/mtrr.txt for details.

       /proc/net
	      various  net  pseudo-files, all of which give the status of some
	      part of the networking layer.  These files contain ASCII	struc-
	      tures  and  are,	therefore, readable with cat(1).  However, the
	      standard netstat(8) suite provides much cleaner access to	 these
	      files.

       /proc/net/arp
	      This  holds  an ASCII readable dump of the kernel ARP table used
	      for address resolutions.	It will show both dynamically  learned
	      and preprogrammed ARP entries.  The format is:

	IP address     HW type	 Flags	   HW address	       Mask   Device
	192.168.0.50   0x1	 0x2	   00:50:BF:25:68:F3   *      eth0
	192.168.0.250  0x1	 0xc	   00:00:00:00:00:00   *      eth0

	      Here "IP address" is the IPv4 address of the machine and the "HW
	      type" is the hardware type of the	 address  from	RFC 826.   The
	      flags are the internal flags of the ARP structure (as defined in
	      /usr/include/linux/if_arp.h) and the "HW address"	 is  the  data
	      link layer mapping for that IP address if it is known.

       /proc/net/dev
	      The  dev pseudo-file contains network device status information.
	      This gives the number of received and sent packets,  the	number
	      of  errors and collisions and other basic statistics.  These are
	      used by the ifconfig(8) program to report	 device	 status.   The
	      format is:

 Inter-|   Receive						  |  Transmit
  face |bytes	 packets errs drop fifo frame compressed multicast|bytes    packets errs drop fifo colls carrier compressed
     lo: 2776770   11307    0	 0    0	    0	       0	 0  2776770   11307    0    0	 0     0       0	  0
   eth0: 1215645    2751    0	 0    0	    0	       0	 0  1782404    4324    0    0	 0   427       0	  0
   ppp0: 1622270    5552    1	 0    0	    0	       0	 0   354130    5669    0    0	 0     0       0	  0
   tap0:    7714      81    0	 0    0	    0	       0	 0     7714	 81    0    0	 0     0       0	  0

       /proc/net/dev_mcast
	      Defined in /usr/src/linux/net/core/dev_mcast.c:
		   indx interface_name	dmi_u dmi_g dmi_address
		   2	eth0		1     0	    01005e000001
		   3	eth1		1     0	    01005e000001
		   4	eth2		1     0	    01005e000001

       /proc/net/igmp
	      Internet	   Group     Management	   Protocol.	 Defined    in
	      /usr/src/linux/net/core/igmp.c.

       /proc/net/rarp
	      This file uses the same format as the arp file and contains  the
	      current reverse mapping database used to provide rarp(8) reverse
	      address lookup services.	If RARP is  not	 configured  into  the
	      kernel, this file will not be present.

       /proc/net/raw
	      Holds  a	dump of the RAW socket table.  Much of the information
	      is not of use apart from debugging.  The "sl" value is the  ker-
	      nel  hash	 slot for the socket, the "local_address" is the local
	      address and protocol number pair.	 "St" is the  internal	status
	      of  the  socket.	The "tx_queue" and "rx_queue" are the outgoing
	      and incoming data queue in terms of kernel  memory  usage.   The
	      "tr", "tm->when", and "rexmits" fields are not used by RAW.  The
	      "uid" field holds the  effective	UID  of	 the  creator  of  the
	      socket.

       /proc/net/snmp
	      This file holds the ASCII data needed for the IP, ICMP, TCP, and
	      UDP management information bases for an SNMP agent.

       /proc/net/tcp
	      Holds a dump of the TCP socket table.  Much of  the  information
	      is  not of use apart from debugging.  The "sl" value is the ker-
	      nel hash slot for the socket, the "local_address" is  the	 local
	      address  and  port number pair.  The "rem_address" is the remote
	      address and port number pair (if connected).  "St" is the inter-
	      nal status of the socket.	 The "tx_queue" and "rx_queue" are the
	      outgoing and incoming data  queue	 in  terms  of	kernel	memory
	      usage.  The "tr", "tm->when", and "rexmits" fields hold internal
	      information of the kernel socket state and are useful  only  for
	      debugging.   The "uid" field holds the effective UID of the cre-
	      ator of the socket.

       /proc/net/udp
	      Holds a dump of the UDP socket table.  Much of  the  information
	      is  not of use apart from debugging.  The "sl" value is the ker-
	      nel hash slot for the socket, the "local_address" is  the	 local
	      address  and  port number pair.  The "rem_address" is the remote
	      address and port number pair (if connected).  "St" is the inter-
	      nal status of the socket.	 The "tx_queue" and "rx_queue" are the
	      outgoing and incoming data  queue	 in  terms  of	kernel	memory
	      usage.   The "tr", "tm->when", and "rexmits" fields are not used
	      by UDP.  The "uid" field holds the effective UID of the  creator
	      of the socket.  The format is:

 sl  local_address rem_address	 st tx_queue rx_queue tr rexmits  tm->when uid
  1: 01642C89:0201 0C642C89:03FF 01 00000000:00000001 01:000071BA 00000000 0
  1: 00000000:0801 00000000:0000 0A 00000000:00000000 00:00000000 6F000100 0
  1: 00000000:0201 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0

       /proc/net/unix
	      Lists  the  UNIX	domain	sockets	 present within the system and
	      their status.  The format is:
	      Num RefCount Protocol Flags    Type St Path
	       0: 00000002 00000000 00000000 0001 03
	       1: 00000001 00000000 00010000 0001 01 /dev/printer

	      The fields are as follows:

	      Num:	the kernel table slot number.

	      RefCount: the number of users of the socket.

	      Protocol: currently always 0.

	      Flags:	the internal kernel flags holding the  status  of  the
			socket.

	      Type:	the  socket  type.   For  SOCK_STREAM sockets, this is
			0001; for SOCK_DGRAM sockets,  it  is  0002;  and  for
			SOCK_SEQPACKET sockets, it is 0005.

	      St:	the internal state of the socket.

	      Path:	the bound path (if any) of the socket.	Sockets in the
			abstract namespace are included in the list,  and  are
			shown  with  a	Path that commences with the character
			'@'.

       /proc/net/netfilter/nfnetlink_queue
	      This file contains information about netfilter userspace	queue-
	      ing,  if	used.  Each line represents a queue.  Queues that have
	      not been subscribed to by userspace are not shown.

		 1   4207     0	 2 65535     0	   0	    0  1
		(1)   (2)    (3)(4)  (5)    (6)	  (7)	   (8)

	      The fields in each line are:

	      (1)  The ID of the queue.	 This matches what is specified in the
		   --queue-num	or  --queue-balance options to the iptables(8)
		   NFQUEUE target.  See iptables-extensions(8) for more infor-
		   mation.

	      (2)  The netlink port ID subscribed to the queue.

	      (3)  The	number	of  packets currently queued and waiting to be
		   processed by the application.

	      (4)  The copy mode of the queue.	It is either 1 (metadata only)
		   or 2 (also copy payload data to userspace).

	      (5)  Copy	 range;	 that  is,  how	 many  bytes of packet payload
		   should be copied to userspace at most.

	      (6)  queue dropped.  Number of packets that had to be dropped by
		   the kernel because too many packets are already waiting for
		   userspace to send back the mandatory accept/drop verdicts.

	      (7)  queue user dropped.	Number of packets  that	 were  dropped
		   within  the	netlink	 subsystem.  Such drops usually happen
		   when the corresponding socket  buffer  is  full;  that  is,
		   userspace is not able to read messages fast enough.

	      (8)  sequence  number.  Every queued packet is associated with a
		   (32-bit) monotonically-increasing  sequence	number.	  This
		   shows the ID of the most recent packet queued.

	      The  last	 number	 exists	 only for compatibility reasons and is
	      always 1.

       /proc/partitions
	      Contains the major and minor numbers of each partition  as  well
	      as the number of 1024-byte blocks and the partition name.

       /proc/pci
	      This  is	a  listing of all PCI devices found during kernel ini-
	      tialization and their configuration.

	      This file has been deprecated in favor of a new /proc  interface
	      for  PCI	(/proc/bus/pci).   It  became  optional	 in  Linux 2.2
	      (available with CONFIG_PCI_OLD_PROC set at kernel	 compilation).
	      It  became  once more nonoptionally enabled in Linux 2.4.	 Next,
	      it was deprecated	 in  Linux  2.6	 (still	 available  with  CON-
	      FIG_PCI_LEGACY_PROC  set),  and finally removed altogether since
	      Linux 2.6.17.

       /proc/profile (since Linux 2.4)
	      This file is present only if the kernel was booted with the pro-
	      file=1  command-line option.  It exposes kernel profiling infor-
	      mation in a binary format for use	 by  readprofile(1).   Writing
	      (e.g.,  an empty string) to this file resets the profiling coun-
	      ters; on some architectures, writing a binary integer "profiling
	      multiplier"  of  size  sizeof(int)  sets the profiling interrupt
	      frequency.

       /proc/scsi
	      A directory with the scsi mid-level pseudo-file and various SCSI
	      low-level driver directories, which contain a file for each SCSI
	      host in this system, all of which give the status of  some  part
	      of  the SCSI IO subsystem.  These files contain ASCII structures
	      and are, therefore, readable with cat(1).

	      You can also write to some of the files to reconfigure the  sub-
	      system or switch certain features on or off.

       /proc/scsi/scsi
	      This  is a listing of all SCSI devices known to the kernel.  The
	      listing is similar to the one seen  during  bootup.   scsi  cur-
	      rently  supports only the add-single-device command which allows
	      root to add a hotplugged device to the list of known devices.

	      The command

		  echo 'scsi add-single-device 1 0 5 0' > /proc/scsi/scsi

	      will cause host scsi1 to scan on SCSI channel 0 for a device  on
	      ID  5 LUN 0.  If there is already a device known on this address
	      or the address is invalid, an error will be returned.

       /proc/scsi/[drivername]
	      [drivername]  can	 currently  be	NCR53c7xx,  aha152x,  aha1542,
	      aha1740, aic7xxx, buslogic, eata_dma, eata_pio, fdomain, in2000,
	      pas16, qlogic, scsi_debug, seagate, t128,	 u15-24f,  ultrastore,
	      or  wd7000.  These directories show up for all drivers that reg-
	      istered at least one SCSI HBA.   Every  directory	 contains  one
	      file  per	 registered  host.  Every host-file is named after the
	      number the host was assigned during initialization.

	      Reading these files will usually show driver and host configura-
	      tion, statistics, and so on.

	      Writing  to  these  files	 allows	 different things on different
	      hosts.  For example, with the latency  and  nolatency  commands,
	      root  can	 switch on and off command latency measurement code in
	      the eata_dma driver.  With the lockup and unlock commands,  root
	      can control bus lockups simulated by the scsi_debug driver.

       /proc/self
	      This  directory  refers  to  the	process	 accessing  the	 /proc
	      filesystem, and is identical to the /proc directory named by the
	      process ID of the same process.

       /proc/slabinfo
	      Information  about  kernel caches.  Since Linux 2.6.16 this file
	      is present only if the CONFIG_SLAB kernel	 configuration	option
	      is enabled.  The columns in /proc/slabinfo are:

		  cache-name
		  num-active-objs
		  total-objs
		  object-size
		  num-active-slabs
		  total-slabs
		  num-pages-per-slab

	      See slabinfo(5) for details.

       /proc/stat
	      kernel/system  statistics.   Varies  with	 architecture.	Common
	      entries include:

	      cpu  3357 0 4313 1362393
		     The  amount  of  time,  measured  in  units  of   USER_HZ
		     (1/100ths	 of   a	 second	 on  most  architectures,  use
		     sysconf(_SC_CLK_TCK) to obtain the right value), that the
		     system spent in various states:

		     user   (1) Time spent in user mode.

		     nice   (2)	 Time  spent  in  user	mode with low priority
			    (nice).

		     system (3) Time spent in system mode.

		     idle   (4) Time spent  in	the  idle  task.   This	 value
			    should  be	USER_HZ	 times the second entry in the
			    /proc/uptime pseudo-file.

		     iowait (since Linux 2.5.41)
			    (5) Time waiting for I/O to complete.

		     irq (since Linux 2.6.0-test4)
			    (6) Time servicing interrupts.

		     softirq (since Linux 2.6.0-test4)
			    (7) Time servicing softirqs.

		     steal (since Linux 2.6.11)
			    (8) Stolen time, which is the time spent in	 other
			    operating  systems	when  running in a virtualized
			    environment

		     guest (since Linux 2.6.24)
			    (9) Time spent running a  virtual  CPU  for	 guest
			    operating  systems	under the control of the Linux
			    kernel.

		     guest_nice (since Linux 2.6.33)
			    (10) Time spent running a niced guest (virtual CPU
			    for	 guest	operating systems under the control of
			    the Linux kernel).

	      page 5741 1808
		     The number of pages the system paged in  and  the	number
		     that were paged out (from disk).

	      swap 1 0
		     The  number  of  swap pages that have been brought in and
		     out.

	      intr 1462898
		     This line shows counts of interrupts serviced since  boot
		     time,  for	 each  of the possible system interrupts.  The
		     first column is the  total	 of  all  interrupts  serviced
		     including	unnumbered  architecture  specific interrupts;
		     each subsequent column is the total for  that  particular
		     numbered interrupt.  Unnumbered interrupts are not shown,
		     only summed into the total.

	      disk_io: (2,0):(31,30,5764,1,2) (3,0):...
		     (major,disk_idx):(noinfo,	   read_io_ops,	    blks_read,
		     write_io_ops, blks_written)
		     (Linux 2.4 only)

	      ctxt 115315
		     The number of context switches that the system underwent.

	      btime 769041601
		     boot   time,  in  seconds	since  the  Epoch,  1970-01-01
		     00:00:00 +0000 (UTC).

	      processes 86031
		     Number of forks since boot.

	      procs_running 6
		     Number of processes in  runnable  state.	(Linux	2.5.45
		     onward.)

	      procs_blocked 2
		     Number  of processes blocked waiting for I/O to complete.
		     (Linux 2.5.45 onward.)

       /proc/swaps
	      Swap areas in use.  See also swapon(8).

       /proc/sys
	      This directory (present since 1.3.57) contains a number of files
	      and  subdirectories  corresponding  to  kernel variables.	 These
	      variables can be read and sometimes  modified  using  the	 /proc
	      filesystem, and the (deprecated) sysctl(2) system call.

	      String values may be terminated by either '\0' or '\n'.

	      Integer  and  long values may be written either in decimal or in
	      hexadecimal notation (e.g. 0x3FFF).  When writing multiple inte-
	      ger or long values, these may be separated by any of the follow-
	      ing whitespace characters: ' ', '\t', or '\n'.  Using other sep-
	      arators leads to the error EINVAL.

       /proc/sys/abi (since Linux 2.4.10)
	      This  directory may contain files with application binary infor-
	      mation.	See  the   Linux   kernel   source   file   Documenta-
	      tion/sysctl/abi.txt for more information.

       /proc/sys/debug
	      This directory may be empty.

       /proc/sys/dev
	      This   directory	contains  device-specific  information	(e.g.,
	      dev/cdrom/info).	On some systems, it may be empty.

       /proc/sys/fs
	      This directory contains the files and subdirectories for	kernel
	      variables related to filesystems.

       /proc/sys/fs/binfmt_misc
	      Documentation  for  files	 in this directory can be found in the
	      Linux kernel sources in Documentation/binfmt_misc.txt.

       /proc/sys/fs/dentry-state (since Linux 2.2)
	      This file contains information about the status of the directory
	      cache  (dcache).	 The  file  contains  six  numbers, nr_dentry,
	      nr_unused,  age_limit  (age  in  seconds),   want_pages	(pages
	      requested by system) and two dummy values.

	      * nr_dentry   is	 the  number  of  allocated  dentries  (dcache
		entries).  This field is unused in Linux 2.2.

	      * nr_unused is the number of unused dentries.

	      * age_limit is the age in seconds after which dcache entries can
		be reclaimed when memory is short.

	      * want_pages   is	  nonzero   when   the	 kernel	  has	called
		shrink_dcache_pages() and the dcache isn't pruned yet.

       /proc/sys/fs/dir-notify-enable
	      This file can be used to disable or enable the dnotify interface
	      described	 in  fcntl(2) on a system-wide basis.  A value of 0 in
	      this file disables the interface, and a value of 1 enables it.

       /proc/sys/fs/dquot-max
	      This file shows the maximum number of cached disk quota entries.
	      On some (2.4) systems, it is not present.	 If the number of free
	      cached disk quota entries is very low and you have some  awesome
	      number of simultaneous system users, you might want to raise the
	      limit.

       /proc/sys/fs/dquot-nr
	      This file shows the number of allocated disk quota  entries  and
	      the number of free disk quota entries.

       /proc/sys/fs/epoll (since Linux 2.6.28)
	      This  directory contains the file max_user_watches, which can be
	      used to limit the amount of kernel memory consumed by the	 epoll
	      interface.  For further details, see epoll(7).

       /proc/sys/fs/file-max
	      This  file  defines  a  system-wide  limit on the number of open
	      files for all processes.	System calls that fail when encounter-
	      ing  this	 limit	fail  with  the error ENFILE.  (See also setr-
	      limit(2), which can be used by a process to set the  per-process
	      limit,  RLIMIT_NOFILE,  on the number of files it may open.)  If
	      you get lots of error messages in the kernel log	about  running
	      out  of  file  handles  (look  for "VFS: file-max limit <number>
	      reached"), try increasing this value:

		  echo 100000 > /proc/sys/fs/file-max

	      Privileged processes (CAP_SYS_ADMIN) can override	 the  file-max
	      limit.

       /proc/sys/fs/file-nr
	      This  (read-only)	 file  contains	 three	numbers: the number of
	      allocated file handles (i.e.,  the  number  of  files  presently
	      opened); the number of free file handles; and the maximum number
	      of file handles (i.e., the same value as /proc/sys/fs/file-max).
	      If the number of allocated file handles is close to the maximum,
	      you should consider increasing the maximum.  Before  Linux  2.6,
	      the  kernel  allocated  file  handles dynamically, but it didn't
	      free them again.	Instead the free file handles were kept	 in  a
	      list  for	 reallocation; the "free file handles" value indicates
	      the size of that list.  A large  number  of  free	 file  handles
	      indicates	 that  there was a past peak in the usage of open file
	      handles.	Since Linux 2.6, the kernel does deallocate freed file
	      handles, and the "free file handles" value is always zero.

       /proc/sys/fs/inode-max (only present until Linux 2.2)
	      This file contains the maximum number of in-memory inodes.  This
	      value should be 3-4 times larger than  the  value	 in  file-max,
	      since  stdin,  stdout  and network sockets also need an inode to
	      handle them.  When you regularly run out of inodes, you need  to
	      increase this value.

	      Starting	with  Linux  2.4, there is no longer a static limit on
	      the number of inodes, and this file is removed.

       /proc/sys/fs/inode-nr
	      This file contains the first two values from inode-state.

       /proc/sys/fs/inode-state
	      This file contains  seven	 numbers:  nr_inodes,  nr_free_inodes,
	      preshrink, and four dummy values (always zero).

	      nr_inodes	 is  the  number  of  inodes the system has allocated.
	      nr_free_inodes represents the number of free inodes.

	      preshrink is nonzero when the nr_inodes > inode-max and the sys-
	      tem  needs  to  prune the inode list instead of allocating more;
	      since Linux 2.4, this field is a dummy value (always zero).

       /proc/sys/fs/inotify (since Linux 2.6.13)
	      This     directory     contains	  files	    max_queued_events,
	      max_user_instances,  and	max_user_watches,  that can be used to
	      limit the amount of kernel memory consumed by the inotify inter-
	      face.  For further details, see inotify(7).

       /proc/sys/fs/lease-break-time
	      This file specifies the grace period that the kernel grants to a
	      process holding a file lease (fcntl(2)) after it has sent a sig-
	      nal to that process notifying it that another process is waiting
	      to open the file.	 If the lease holder does not remove or	 down-
	      grade  the  lease	 within this grace period, the kernel forcibly
	      breaks the lease.

       /proc/sys/fs/leases-enable
	      This  file  can  be  used	 to  enable  or	 disable  file	leases
	      (fcntl(2))  on  a	 system-wide basis.  If this file contains the
	      value 0, leases are disabled.  A nonzero value enables leases.

       /proc/sys/fs/mqueue (since Linux 2.6.6)
	      This  directory  contains	 files	 msg_max,   msgsize_max,   and
	      queues_max,  controlling	the  resources	used  by POSIX message
	      queues.  See mq_overview(7) for details.

       /proc/sys/fs/nr_open (since Linux 2.6.25)
	      This  file  imposes  ceiling  on	the   value   to   which   the
	      RLIMIT_NOFILE  resource  limit can be raised (see getrlimit(2)).
	      This ceiling is enforced for both	 unprivileged  and  privileged
	      process.	 The  default  value in this file is 1048576.  (Before
	      Linux 2.6.25, the ceiling for RLIMIT_NOFILE  was	hard-coded  to
	      the same value.)

       /proc/sys/fs/overflowgid and /proc/sys/fs/overflowuid
	      These  files  allow you to change the value of the fixed UID and
	      GID.  The default	 is  65534.   Some  filesystems	 support  only
	      16-bit  UIDs  and	 GIDs,	although in Linux UIDs and GIDs are 32
	      bits.  When one of these	filesystems  is	 mounted  with	writes
	      enabled, any UID or GID that would exceed 65535 is translated to
	      the overflow value before being written to disk.

       /proc/sys/fs/pipe-max-size (since Linux 2.6.35)
	      The value in this file defines an upper limit  for  raising  the
	      capacity	of  a  pipe using the fcntl(2) F_SETPIPE_SZ operation.
	      This limit applies only to unprivileged processes.  The  default
	      value  for  this	file is 1,048,576.  The value assigned to this
	      file may be  rounded  upward,  to	 reflect  the  value  actually
	      employed	for  a	convenient  implementation.   To determine the
	      rounded-up value,	 display  the  contents	 of  this  file	 after
	      assigning a value to it.	The minimum value that can be assigned
	      to this file is the system page size.

       /proc/sys/fs/protected_hardlinks (since Linux 3.6)
	      When the value in this file is 0, no restrictions are placed  on
	      the  creation of hard links (i.e., this is the historical behav-
	      ior before Linux 3.6).  When the value in this file is 1, a hard
	      link  can be created to a target file only if one of the follow-
	      ing conditions is true:

	      *	 The caller has the CAP_FOWNER capability.

	      *	 The filesystem UID of the process creating the	 link  matches
		 the  owner  (UID) of the target file (as described in creden-
		 tials(7), a process's filesystem UID is normally the same  as
		 its effective UID).

	      *	 All of the following conditions are true:

		  o  the target is a regular file;

		  o  the  target  file	does not have its set-user-ID mode bit
		     enabled;

		  o  the target file does not have both its  set-group-ID  and
		     group-executable mode bits enabled; and

		  o  the  caller  has  permission to read and write the target
		     file (either via the file's permissions mask  or  because
		     it has suitable capabilities).

	      The  default  value  in  this file is 0.	Setting the value to 1
	      prevents a longstanding class of security issues caused by hard-
	      link-based  time-of-check, time-of-use races, most commonly seen
	      in world-writable directories such as /tmp.  The	common	method
	      of  exploiting  this  flaw is to cross privilege boundaries when
	      following a given hard link (i.e., a root process follows a hard
	      link created by another user).  Additionally, on systems without
	      separated partitions, this stops unauthorized users  from	 "pin-
	      ning"  vulnerable	 set-user-ID  and  set-group-ID	 files against
	      being upgraded by	 the  administrator,  or  linking  to  special
	      files.

       /proc/sys/fs/protected_symlinks (since Linux 3.6)
	      When  the value in this file is 0, no restrictions are placed on
	      following symbolic links (i.e., this is the historical  behavior
	      before  Linux  3.6).  When the value in this file is 1, symbolic
	      links are followed only in the following circumstances:

	      *	 the filesystem UID of the process following the link  matches
		 the owner (UID) of the symbolic link (as described in creden-
		 tials(7), a process's filesystem UID is normally the same  as
		 its effective UID);

	      *	 the link is not in a sticky world-writable directory; or

	      *	 the  symbolic	link  and  its	parent directory have the same
		 owner (UID)

	      A system call that fails to follow a symbolic  link  because  of
	      the above restrictions returns the error EACCES in errno.

	      The  default  value  in  this file is 0.	Setting the value to 1
	      avoids a longstanding class of security issues based on time-of-
	      check, time-of-use races when accessing symbolic links.

       /proc/sys/fs/suid_dumpable (since Linux 2.6.13)
	      The  value  in  this  file is assigned to a process's "dumpable"
	      flag in the circumstances described in prctl(2).	In effect, the
	      value  in	 this file determines whether core dump files are pro-
	      duced for set-user-ID or otherwise  protected/tainted  binaries.
	      Three different integer values can be specified:

	      0 (default)
		     This  provides  the traditional (pre-Linux 2.6.13) behav-
		     ior.  A core dump will not	 be  produced  for  a  process
		     which  has	 changed  credentials  (by calling seteuid(2),
		     setgid(2), or similar, or by executing a  set-user-ID  or
		     set-group-ID  program) or whose binary does not have read
		     permission enabled.

	      1 ("debug")
		     All processes dump core when possible.  The core dump  is
		     owned  by	the  filesystem user ID of the dumping process
		     and no security is applied.  This is intended for	system
		     debugging situations only.	 Ptrace is unchecked.

	      2 ("suidsafe")
		     Any  binary  which	 normally would not be dumped (see "0"
		     above) is dumped readable by root only.  This allows  the
		     user  to  remove  the  core dump file but not to read it.
		     For security reasons core dumps in	 this  mode  will  not
		     overwrite	one  another  or  other	 files.	  This mode is
		     appropriate when administrators are attempting  to	 debug
		     problems in a normal environment.

		     Additionally, since Linux 3.6, /proc/sys/kernel/core_pat-
		     tern must either be an absolute pathname or a  pipe  com-
		     mand,  as	detailed in core(5).  Warnings will be written
		     to the kernel log if core_pattern does not	 follow	 these
		     rules, and no core dump will be produced.

       /proc/sys/fs/super-max
	      This  file  controls the maximum number of superblocks, and thus
	      the maximum number of mounted filesystems the kernel  can	 have.
	      You  need	 increase  only	 super-max  if	you need to mount more
	      filesystems than the current value in super-max allows you to.

       /proc/sys/fs/super-nr
	      This file contains the number of filesystems currently mounted.

       /proc/sys/kernel
	      This directory contains files  controlling  a  range  of	kernel
	      parameters, as described below.

       /proc/sys/kernel/acct
	      This  file contains three numbers: highwater, lowwater, and fre-
	      quency.  If BSD-style process accounting is enabled, these  val-
	      ues control its behavior.	 If free space on filesystem where the
	      log lives goes below lowwater percent, accounting suspends.   If
	      free  space  gets	 above	highwater percent, accounting resumes.
	      frequency determines how often the kernel checks the  amount  of
	      free  space  (value is in seconds).  Default values are 4, 2 and
	      30.  That is, suspend accounting if 2% or less  space  is	 free;
	      resume  it  if  4%  or  more space is free; consider information
	      about amount of free space valid for 30 seconds.

       /proc/sys/kernel/auto_msgmni (Linux 2.6.27 to 3.18)
	      From Linux 2.6.27 to 3.18, this file was used to control	recom-
	      puting of the value in /proc/sys/kernel/msgmni upon the addition
	      or removal of memory or  upon  IPC  namespace  creation/removal.
	      Echoing  "1" into this file enabled msgmni automatic recomputing
	      (and triggered a recomputation of msgmni based  on  the  current
	      amount of available memory and number of IPC namespaces).	 Echo-
	      ing "0" disabled automatic recomputing.  (Automatic  recomputing
	      was  also	 disabled  if  a  value	 was  explicitly  assigned  to
	      /proc/sys/kernel/msgmni.)	 The default value in auto_msgmni  was
	      1.

	      Since  Linux  3.19,  the	content	 of  this  file	 has no effect
	      (because msgmni defaults to near the  maximum  value  possible),
	      and reads from this file always return the value "0".

       /proc/sys/kernel/cap_last_cap (since Linux 3.2)
	      See capabilities(7).

       /proc/sys/kernel/cap-bound (from Linux 2.2 to 2.6.24)
	      This  file holds the value of the kernel capability bounding set
	      (expressed as a signed  decimal  number).	  This	set  is	 ANDed
	      against	the   capabilities   permitted	to  a  process	during
	      execve(2).  Starting with Linux 2.6.25, the system-wide capabil-
	      ity  bounding  set disappeared, and was replaced by a per-thread
	      bounding set; see capabilities(7).

       /proc/sys/kernel/core_pattern
	      See core(5).

       /proc/sys/kernel/core_uses_pid
	      See core(5).

       /proc/sys/kernel/ctrl-alt-del
	      This file controls the handling of Ctrl-Alt-Del  from  the  key-
	      board.   When  the  value	 in  this  file	 is 0, Ctrl-Alt-Del is
	      trapped and sent to the init(1) program  to  handle  a  graceful
	      restart.	 When the value is greater than zero, Linux's reaction
	      to a Vulcan Nerve Pinch (tm) will be an immediate reboot,	 with-
	      out  even syncing its dirty buffers.  Note: when a program (like
	      dosemu) has the keyboard in  "raw"  mode,	 the  ctrl-alt-del  is
	      intercepted by the program before it ever reaches the kernel tty
	      layer, and it's up to the program to decide what to do with it.

       /proc/sys/kernel/dmesg_restrict (since Linux 2.6.37)
	      The value in this file determines who can see kernel syslog con-
	      tents.   A  value of 0 in this file imposes no restrictions.  If
	      the value is 1, only privileged users can read the  kernel  sys-
	      log.   (See  syslog(2) for more details.)	 Since Linux 3.4, only
	      users with the CAP_SYS_ADMIN capability may change the value  in
	      this file.

       /proc/sys/kernel/domainname and /proc/sys/kernel/hostname
	      can  be  used  to	 set the NIS/YP domainname and the hostname of
	      your box in exactly the same way as the  commands	 domainname(1)
	      and hostname(1), that is:

		  # echo 'darkstar' > /proc/sys/kernel/hostname
		  # echo 'mydomain' > /proc/sys/kernel/domainname

	      has the same effect as

		  # hostname 'darkstar'
		  # domainname 'mydomain'

	      Note,  however, that the classic darkstar.frop.org has the host-
	      name "darkstar" and DNS (Internet Domain Name Server) domainname
	      "frop.org", not to be confused with the NIS (Network Information
	      Service) or YP (Yellow  Pages)  domainname.   These  two	domain
	      names  are  in general different.	 For a detailed discussion see
	      the hostname(1) man page.

       /proc/sys/kernel/hotplug
	      This file contains the path for the hotplug policy  agent.   The
	      default value in this file is /sbin/hotplug.

       /proc/sys/kernel/htab-reclaim
	      (PowerPC	only) If this file is set to a nonzero value, the Pow-
	      erPC htab (see kernel  file  Documentation/powerpc/ppc_htab.txt)
	      is pruned each time the system hits the idle loop.

       /proc/sys/kernel/kptr_restrict (since Linux 2.6.38)
	      The  value  in this file determines whether kernel addresses are
	      exposed via /proc files and other interfaces.  A value of	 0  in
	      this  file  imposes  no restrictions.  If the value is 1, kernel
	      pointers printed using the %pK format specifier will be replaced
	      with  zeros  unless  the user has the CAP_SYSLOG capability.  If
	      the value is 2, kernel pointers printed  using  the  %pK	format
	      specifier	 will  be replaced with zeros regardless of the user's
	      capabilities.  The initial default value for this	 file  was  1,
	      but  the	default was changed to 0 in Linux 2.6.39.  Since Linux
	      3.4, only users with the CAP_SYS_ADMIN capability can change the
	      value in this file.

       /proc/sys/kernel/l2cr
	      (PowerPC	only)  This  file contains a flag that controls the L2
	      cache of G3 processor boards.  If	 0,  the  cache	 is  disabled.
	      Enabled if nonzero.

       /proc/sys/kernel/modprobe
	      This  file  contains the path for the kernel module loader.  The
	      default value is /sbin/modprobe.	The file is  present  only  if
	      the  kernel  is  built  with  the CONFIG_MODULES (CONFIG_KMOD in
	      Linux 2.6.26 and earlier) option enabled.	 It  is	 described  by
	      the  Linux  kernel  source  file Documentation/kmod.txt (present
	      only in kernel 2.4 and earlier).

       /proc/sys/kernel/modules_disabled (since Linux 2.6.31)
	      A toggle value indicating if modules are allowed to be loaded in
	      an  otherwise  modular kernel.  This toggle defaults to off (0),
	      but can be set true (1).	Once  true,  modules  can  be  neither
	      loaded nor unloaded, and the toggle cannot be set back to false.
	      The file is present only if the kernel is built  with  the  CON-
	      FIG_MODULES option enabled.

       /proc/sys/kernel/msgmax (since Linux 2.2)
	      This  file  defines  a  system-wide limit specifying the maximum
	      number of bytes in a single message written on a System  V  mes-
	      sage queue.

       /proc/sys/kernel/msgmni (since Linux 2.4)
	      This file defines the system-wide limit on the number of message
	      queue identifiers.  See also /proc/sys/kernel/auto_msgmni.

       /proc/sys/kernel/msgmnb (since Linux 2.2)
	      This file defines a system-wide parameter used to initialize the
	      msg_qbytes setting for subsequently created message queues.  The
	      msg_qbytes setting specifies the maximum number  of  bytes  that
	      may be written to the message queue.

       /proc/sys/kernel/ngroups_max (since Linux 2.6.4)
	      This  is	a  read-only file that displays the upper limit on the
	      number of a process's group memberships.

       /proc/sys/kernel/ostype and /proc/sys/kernel/osrelease
	      These files give substrings of /proc/version.

       /proc/sys/kernel/overflowgid and /proc/sys/kernel/overflowuid
	      These files duplicate  the  files	 /proc/sys/fs/overflowgid  and
	      /proc/sys/fs/overflowuid.

       /proc/sys/kernel/panic
	      This  file  gives	 read/write  access  to	 the  kernel  variable
	      panic_timeout.  If this is zero,	the  kernel  will  loop	 on  a
	      panic;  if  nonzero, it indicates that the kernel should autore-
	      boot after this number of seconds.  When you  use	 the  software
	      watchdog device driver, the recommended setting is 60.

       /proc/sys/kernel/panic_on_oops (since Linux 2.5.68)
	      This  file controls the kernel's behavior when an oops or BUG is
	      encountered.  If this file contains 0, then the system tries  to
	      continue	operation.  If it contains 1, then the system delays a
	      few seconds (to give klogd time to record the oops  output)  and
	      then   panics.   If  the	/proc/sys/kernel/panic	file  is  also
	      nonzero, then the machine will be rebooted.

       /proc/sys/kernel/pid_max (since Linux 2.5.34)
	      This file specifies the value at which PIDs wrap	around	(i.e.,
	      the  value  in  this  file is one greater than the maximum PID).
	      PIDs greater than this value are not allocated; thus, the	 value
	      in  this file also acts as a system-wide limit on the total num-
	      ber of processes and threads.  The default value for this	 file,
	      32768,  results in the same range of PIDs as on earlier kernels.
	      On 32-bit platforms, 32768 is the maximum value for pid_max.  On
	      64-bit  systems,	pid_max	 can  be  set  to any value up to 2^22
	      (PID_MAX_LIMIT, approximately 4 million).

       /proc/sys/kernel/powersave-nap (PowerPC only)
	      This file contains a flag.  If set, Linux-PPC will use the "nap"
	      mode of powersaving, otherwise the "doze" mode will be used.

       /proc/sys/kernel/printk
	      See syslog(2).

       /proc/sys/kernel/pty (since Linux 2.6.4)
	      This directory contains two files relating to the number of UNIX
	      98 pseudoterminals (see pts(4)) on the system.

       /proc/sys/kernel/pty/max
	      This file defines the maximum number of pseudoterminals.

       /proc/sys/kernel/pty/nr
	      This read-only file indicates how many pseudoterminals are  cur-
	      rently in use.

       /proc/sys/kernel/random
	      This directory contains various parameters controlling the oper-
	      ation of the file /dev/random.  See random(4) for further infor-
	      mation.

       /proc/sys/kernel/random/uuid (since Linux 2.4)
	      Each  read from this read-only file returns a randomly generated
	      128-bit UUID, as a string in the standard UUID format.

       /proc/sys/kernel/randomize_va_space (since Linux 2.6.12)
	      Select the address space layout randomization (ASLR) policy  for
	      the  system  (on architectures that support ASLR).  Three values
	      are supported for this file:

	      0	 Turn ASLR off.	 This is the default  for  architectures  that
		 don't	support	 ASLR,	and when the kernel is booted with the
		 norandmaps parameter.

	      1	 Make the addresses of mmap(2) allocations, the stack, and the
		 VDSO  page  randomized.   Among other things, this means that
		 shared libraries will be loaded at randomized addresses.  The
		 text  segment of PIE-linked binaries will also be loaded at a
		 randomized address.  This value is the default if the	kernel
		 was configured with CONFIG_COMPAT_BRK.

	      2	 (Since	 Linux	2.6.25) Also support heap randomization.  This
		 value is the default if the kernel was	 not  configured  with
		 CONFIG_COMPAT_BRK.

       /proc/sys/kernel/real-root-dev
	      This file is documented in the Linux kernel source file Documen-
	      tation/initrd.txt.

       /proc/sys/kernel/reboot-cmd (Sparc only)
	      This file seems to be a way to give an  argument	to  the	 SPARC
	      ROM/Flash	 boot  loader.	 Maybe	to  tell  it  what to do after
	      rebooting?

       /proc/sys/kernel/rtsig-max
	      (Only in kernels up to and including  2.6.7;  see	 setrlimit(2))
	      This  file can be used to tune the maximum number of POSIX real-
	      time (queued) signals that can be outstanding in the system.

       /proc/sys/kernel/rtsig-nr
	      (Only in kernels up to and including 2.6.7.)   This  file	 shows
	      the number POSIX real-time signals currently queued.

       /proc/sys/kernel/sched_rr_timeslice_ms (since Linux 3.9)
	      See sched_rr_get_interval(2).

       /proc/sys/kernel/sched_rt_period_us (Since Linux 2.6.25)
	      See sched(7).

       /proc/sys/kernel/sched_rt_runtime_us (Since Linux 2.6.25)
	      See sched(7).

       /proc/sys/kernel/sem (since Linux 2.4)
	      This  file  contains  4 numbers defining limits for System V IPC
	      semaphores.  These fields are, in order:

	      SEMMSL  The maximum semaphores per semaphore set.

	      SEMMNS  A system-wide limit on the number of semaphores  in  all
		      semaphore sets.

	      SEMOPM  The  maximum  number of operations that may be specified
		      in a semop(2) call.

	      SEMMNI  A system-wide limit on the maximum number	 of  semaphore
		      identifiers.

       /proc/sys/kernel/sg-big-buff
	      This file shows the size of the generic SCSI device (sg) buffer.
	      You can't tune it just yet, but you could change it  at  compile
	      time  by	editing	 include/scsi/sg.h  and	 changing the value of
	      SG_BIG_BUFF.  However, there shouldn't be any reason  to	change
	      this value.

       /proc/sys/kernel/shm_rmid_forced (since Linux 3.1)
	      If  this	file  is set to 1, all System V shared memory segments
	      will be marked for destruction as soon as the number of attached
	      processes	 falls to zero; in other words, it is no longer possi-
	      ble to create shared memory segments that exist independently of
	      any attached process.

	      The effect is as though a shmctl(2) IPC_RMID is performed on all
	      existing segments as well as all segments created in the	future
	      (until  this  file  is reset to 0).  Note that existing segments
	      that are attached to no process will  be	immediately  destroyed
	      when  this  file	is  set	 to  1.	 Setting this option will also
	      destroy segments that were created,  but	never  attached,  upon
	      termination  of  the  process  that  created  the	 segment  with
	      shmget(2).

	      Setting this file to 1 provides a way of ensuring that all  Sys-
	      tem  V  shared  memory segments are counted against the resource
	      usage and resource limits (see the description of	 RLIMIT_AS  in
	      getrlimit(2)) of at least one process.

	      Because  setting	this  file to 1 produces behavior that is non-
	      standard and could also break existing applications, the default
	      value  in this file is 0.	 Only set this file to 1 if you have a
	      good understanding of the semantics of  the  applications	 using
	      System V shared memory on your system.

       /proc/sys/kernel/shmall (since Linux 2.2)
	      This  file contains the system-wide limit on the total number of
	      pages of System V shared memory.

       /proc/sys/kernel/shmmax (since Linux 2.2)
	      This file can be used to query and set the run-time limit on the
	      maximum  (System	V  IPC) shared memory segment size that can be
	      created.	Shared memory segments up to 1GB are now supported  in
	      the kernel.  This value defaults to SHMMAX.

       /proc/sys/kernel/shmmni (since Linux 2.4)
	      This  file  specifies the system-wide maximum number of System V
	      shared memory segments that can be created.

       /proc/sys/kernel/sysctl_writes_strict (since Linux 3.16)
	      The value in this file determines how the	 file  offset  affects
	      the  behavior of updating entries in files under /proc/sys.  The
	      file has three possible values:

	      -1  This provides legacy	handling,  with	 no  printk  warnings.
		  Each	write(2)  must	fully contain the value to be written,
		  and multiple writes on the same file descriptor  will	 over-
		  write the entire value, regardless of the file position.

	      0	  (default)  This  provides  the  same behavior as for -1, but
		  printk warnings  are	written	 for  processes	 that  perform
		  writes when the file offset is not 0.

	      1	  Respect  the file offset when writing strings into /proc/sys
		  files.  Multiple writes will append  to  the	value  buffer.
		  Anything written beyond the maximum length of the value buf-
		  fer will be ignored.	Writes to  numeric  /proc/sys  entries
		  must	always be at file offset 0 and the value must be fully
		  contained in the buffer provided to write(2).

       /proc/sys/kernel/sysrq
	      This file controls the functions allowed to be  invoked  by  the
	      SysRq  key.   By default, the file contains 1 meaning that every
	      possible SysRq request is allowed	 (in  older  kernel  versions,
	      SysRq was disabled by default, and you were required to specifi-
	      cally enable it at run-time, but this is not the case any more).
	      Possible values in this file are:

	      0	   Disable sysrq completely

	      1	   Enable all functions of sysrq

	      > 1  Bit mask of allowed sysrq functions, as follows:
		     2	Enable control of console logging level
		     4	Enable control of keyboard (SAK, unraw)
		     8	Enable debugging dumps of processes etc.
		    16	Enable sync command
		    32	Enable remount read-only
		    64	Enable signaling of processes (term, kill, oom-kill)
		   128	Allow reboot/poweroff
		   256	Allow nicing of all real-time tasks

	      This  file is present only if the CONFIG_MAGIC_SYSRQ kernel con-
	      figuration option is enabled.  For further details see the Linux
	      kernel source file Documentation/sysrq.txt.

       /proc/sys/kernel/version
	      This file contains a string such as:

		  #5 Wed Feb 25 21:49:24 MET 1998

	      The  "#5"	 means	that  this is the fifth kernel built from this
	      source base and the date following it  indicates	the  time  the
	      kernel was built.

       /proc/sys/kernel/threads-max (since Linux 2.3.11)
	      This  file  specifies  the  system-wide  limit  on the number of
	      threads (tasks) that can be created on the system.

	      Since Linux 4.1, the value that can be written to threads-max is
	      bounded.	The minimum value that can be written is 20.  The max-
	      imum value  that	can  be	 written  is  given  by	 the  constant
	      FUTEX_TID_MASK  (0x3fffffff).   If a value outside of this range
	      is written to threads-max, the error EINVAL occurs.

	      The value written is checked against the	available  RAM	pages.
	      If the thread structures would occupy too much (more than 1/8th)
	      of the available RAM pages, threads-max is reduced accordingly.

       /proc/sys/kernel/yama/ptrace_scope (since Linux 3.5)
	      See ptrace(2).

       /proc/sys/kernel/zero-paged (PowerPC only)
	      This file contains a flag.  When	enabled	 (nonzero),  Linux-PPC
	      will  pre-zero  pages  in	 the  idle  loop, possibly speeding up
	      get_free_pages.

       /proc/sys/net
	      This directory contains networking stuff.	 Explanations for some
	      of  the  files  under  this directory can be found in tcp(7) and
	      ip(7).

       /proc/sys/net/core/bpf_jit_enable
	      See bpf(2).

       /proc/sys/net/core/somaxconn
	      This file defines a ceiling value for the	 backlog  argument  of
	      listen(2); see the listen(2) manual page for details.

       /proc/sys/proc
	      This directory may be empty.

       /proc/sys/sunrpc
	      This  directory  supports	 Sun remote procedure call for network
	      filesystem (NFS).	 On some systems, it is not present.

       /proc/sys/vm
	      This directory contains files for memory management tuning, buf-
	      fer and cache management.

       /proc/sys/vm/compact_memory (since Linux 2.6.35)
	      When  1  is  written  to this file, all zones are compacted such
	      that free memory is available in contiguous blocks where	possi-
	      ble.   The  effect  of  this  action  can	 be  seen by examining
	      /proc/buddyinfo.

	      Only present if  the  kernel  was	 configured  with  CONFIG_COM-
	      PACTION.

       /proc/sys/vm/drop_caches (since Linux 2.6.16)
	      Writing  to  this	 file  causes the kernel to drop clean caches,
	      dentries, and inodes from memory, causing that memory to	become
	      free.  This can be useful for memory management testing and per-
	      forming reproducible filesystem benchmarks.  Because writing  to
	      this  file  causes  the  benefits	 of caching to be lost, it can
	      degrade overall system performance.

	      To free pagecache, use:

		  echo 1 > /proc/sys/vm/drop_caches

	      To free dentries and inodes, use:

		  echo 2 > /proc/sys/vm/drop_caches

	      To free pagecache, dentries and inodes, use:

		  echo 3 > /proc/sys/vm/drop_caches

	      Because writing to this file is a nondestructive	operation  and
	      dirty  objects  are  not	freeable,  the user should run sync(1)
	      first.

       /proc/sys/vm/legacy_va_layout (since Linux 2.6.9)
	      If nonzero, this disables the new 32-bit memory-mapping  layout;
	      the kernel will use the legacy (2.4) layout for all processes.

       /proc/sys/vm/memory_failure_early_kill (since Linux 2.6.32)
	      Control  how  to kill processes when an uncorrected memory error
	      (typically a 2-bit error in a memory module) that cannot be han-
	      dled  by	the  kernel is detected in the background by hardware.
	      In some cases (like the page still having a valid copy on disk),
	      the kernel will handle the failure transparently without affect-
	      ing any applications.  But if there is no other up-to-date  copy
	      of  the data, it will kill processes to prevent any data corrup-
	      tions from propagating.

	      The file has one of the following values:

	      1:  Kill all processes that have	the  corrupted-and-not-reload-
		  able	page  mapped  as  soon	as the corruption is detected.
		  Note this is not supported for a few types  of  pages,  like
		  kernel  internally  allocated	 data  or  the swap cache, but
		  works for the majority of user pages.

	      0:  Only unmap the corrupted page from all  processes  and  kill
		  only a process that tries to access it.

	      The  kill is performed using a SIGBUS signal with si_code set to
	      BUS_MCEERR_AO.  Processes can handle this if they want  to;  see
	      sigaction(2) for more details.

	      This  feature  is	 active	 only  on architectures/platforms with
	      advanced machine check handling  and  depends  on	 the  hardware
	      capabilities.

	      Applications  can override the memory_failure_early_kill setting
	      individually with the prctl(2) PR_MCE_KILL operation.

	      Only present if  the  kernel  was	 configured  with  CONFIG_MEM-
	      ORY_FAILURE.

       /proc/sys/vm/memory_failure_recovery (since Linux 2.6.32)
	      Enable memory failure recovery (when supported by the platform)

	      1:  Attempt recovery.

	      0:  Always panic on a memory failure.

	      Only  present  if	 the  kernel  was  configured with CONFIG_MEM-
	      ORY_FAILURE.

       /proc/sys/vm/oom_dump_tasks (since Linux 2.6.25)
	      Enables a system-wide task dump (excluding kernel threads) to be
	      produced	when  the  kernel  performs  an OOM-killing.  The dump
	      includes	the  following	information  for  each	task  (thread,
	      process): thread ID, real user ID, thread group ID (process ID),
	      virtual memory size, resident set size, the CPU that the task is
	      scheduled	  on,	oom_adj	  score	  (see	 the   description  of
	      /proc/[pid]/oom_adj), and command	 name.	 This  is  helpful  to
	      determine	 why  the  OOM-killer  was invoked and to identify the
	      rogue task that caused it.

	      If this contains the value zero, this information is suppressed.
	      On  very	large  systems	with thousands of tasks, it may not be
	      feasible to dump the memory  state  information  for  each  one.
	      Such systems should not be forced to incur a performance penalty
	      in OOM situations when the information may not be desired.

	      If this is set to nonzero, this information  is  shown  whenever
	      the OOM-killer actually kills a memory-hogging task.

	      The default value is 0.

       /proc/sys/vm/oom_kill_allocating_task (since Linux 2.6.24)
	      This enables or disables killing the OOM-triggering task in out-
	      of-memory situations.

	      If this is set to zero, the OOM-killer  will  scan  through  the
	      entire  tasklist	and select a task based on heuristics to kill.
	      This normally selects a rogue memory-hogging task that frees  up
	      a large amount of memory when killed.

	      If  this is set to nonzero, the OOM-killer simply kills the task
	      that triggered the out-of-memory condition.  This avoids a  pos-
	      sibly expensive tasklist scan.

	      If  /proc/sys/vm/panic_on_oom  is	 nonzero,  it takes precedence
	      over whatever value is  used  in	/proc/sys/vm/oom_kill_allocat-
	      ing_task.

	      The default value is 0.

       /proc/sys/vm/overcommit_kbytes (since Linux 3.14)
	      This writable file provides an alternative to /proc/sys/vm/over-
	      commit_ratio    for    controlling    the	   CommitLimit	  when
	      /proc/sys/vm/overcommit_memory  has  the value 2.	 It allows the
	      amount of memory overcommitting to be specified as  an  absolute
	      value  (in  kB),	rather	than  as a percentage, as is done with
	      overcommit_ratio.	 This allows for finer-grained control of Com-
	      mitLimit on systems with extremely large memory sizes.

	      Only  one	 of  overcommit_kbytes or overcommit_ratio can have an
	      effect: if overcommit_kbytes has a nonzero  value,  then	it  is
	      used  to	calculate  CommitLimit,	 otherwise overcommit_ratio is
	      used.  Writing a value to either of these files causes the value
	      in the other file to be set to zero.

       /proc/sys/vm/overcommit_memory
	      This  file  contains  the kernel virtual memory accounting mode.
	      Values are:

		     0: heuristic overcommit (this is the default)
		     1: always overcommit, never check
		     2: always check, never overcommit

	      In mode 0, calls of mmap(2) with MAP_NORESERVE are not  checked,
	      and  the default check is very weak, leading to the risk of get-
	      ting a process "OOM-killed".  Under Linux 2.4, any nonzero value
	      implies mode 1.

	      In mode 2 (available since Linux 2.6), the total virtual address
	      space that can be allocated (CommitLimit	in  /proc/meminfo)  is
	      calculated as

		  CommitLimit = (total_RAM - total_huge_TLB) *
				overcommit_ratio / 100 + total_swap

	      where:

		   *  total_RAM is the total amount of RAM on the system;

		   *  total_huge_TLB  is  the  amount  of memory set aside for
		      huge pages;

		   *  overcommit_ratio is the value  in	 /proc/sys/vm/overcom-
		      mit_ratio; and

		   *  total_swap is the amount of swap space.

	      For  example,  on	 a  system  with 16GB of physical RAM, 16GB of
	      swap, no space dedicated to huge pages, and an  overcommit_ratio
	      of 50, this formula yields a CommitLimit of 24GB.

	      Since Linux 3.14, if the value in /proc/sys/vm/overcommit_kbytes
	      is nonzero, then CommitLimit is instead calculated as:

		  CommitLimit = overcommit_kbytes + total_swap

       /proc/sys/vm/overcommit_ratio (since Linux 2.6.0)
	      This writable file defines a percentage by which memory  can  be
	      overcommitted.   The  default  value in the file is 50.  See the
	      description of /proc/sys/vm/overcommit_memory.

       /proc/sys/vm/panic_on_oom (since Linux 2.6.18)
	      This enables or disables a kernel panic in an out-of-memory sit-
	      uation.

	      If this file is set to the value 0, the kernel's OOM-killer will
	      kill some rogue process.	Usually, the  OOM-killer  is  able  to
	      kill a rogue process and the system will survive.

	      If  this	file  is  set to the value 1, then the kernel normally
	      panics when out-of-memory happens.  However, if a process limits
	      allocations  to  certain	nodes  using memory policies (mbind(2)
	      MPOL_BIND) or cpusets (cpuset(7)) and those nodes	 reach	memory
	      exhaustion  status, one process may be killed by the OOM-killer.
	      No panic occurs in this case: because other nodes' memory may be
	      free,  this  means the system as a whole may not have reached an
	      out-of-memory situation yet.

	      If this file is set to the value 2,  the	kernel	always	panics
	      when an out-of-memory condition occurs.

	      The default value is 0.  1 and 2 are for failover of clustering.
	      Select either according to your policy of failover.

       /proc/sys/vm/swappiness
	      The value in this file controls how aggressively the kernel will
	      swap memory pages.  Higher values increase aggressiveness, lower
	      values decrease aggressiveness.  The default value is 60.

       /proc/sysrq-trigger (since Linux 2.4.21)
	      Writing a character to this file triggers the same  SysRq	 func-
	      tion  as	typing	ALT-SysRq-<character>  (see the description of
	      /proc/sys/kernel/sysrq).	This file is normally writable only by
	      root.  For further details see the Linux kernel source file Doc-
	      umentation/sysrq.txt.

       /proc/sysvipc
	      Subdirectory containing  the  pseudo-files  msg,	sem  and  shm.
	      These  files  list the System V Interprocess Communication (IPC)
	      objects (respectively: message queues,  semaphores,  and	shared
	      memory)  that  currently	exist on the system, providing similar
	      information to that available via	 ipcs(1).   These  files  have
	      headers  and  are	 formatted  (one IPC object per line) for easy
	      understanding.  svipc(7)	provides  further  background  on  the
	      information shown by these files.

       /proc/thread-self (since Linux 3.17)
	      This directory refers to the thread accessing the /proc filesys-
	      tem, and is identical  to	 the  /proc/self/task/[tid]  directory
	      named by the process thread ID ([tid]) of the same thread.

       /proc/timer_list (since Linux 2.6.21)
	      This  read-only  file  exposes  a	 list of all currently pending
	      (high-resolution) timers, all  clock-event  sources,  and	 their
	      parameters in a human-readable form.

       /proc/timer_stats (since Linux 2.6.21)
	      This  is	a  debugging facility to make timer (ab)use in a Linux
	      system visible to kernel and user-space developers.  It  can  be
	      used  by	kernel	and user-space developers to verify that their
	      code does not make undue use of timers.  The goal	 is  to	 avoid
	      unnecessary wakeups, thereby optimizing power consumption.

	      If  enabled in the kernel (CONFIG_TIMER_STATS), but not used, it
	      has almost zero runtime overhead and a  relatively  small	 data-
	      structure	 overhead.   Even if collection is enabled at runtime,
	      overhead is low: all  the	 locking  is  per-CPU  and  lookup  is
	      hashed.

	      The  /proc/timer_stats  file  is	used  both to control sampling
	      facility and to read out the sampled information.

	      The timer_stats functionality is inactive on bootup.  A sampling
	      period can be started using the following command:

		  # echo 1 > /proc/timer_stats

	      The following command stops a sampling period:

		  # echo 0 > /proc/timer_stats

	      The statistics can be retrieved by:

		  $ cat /proc/timer_stats

	      While  sampling  is enabled, each readout from /proc/timer_stats
	      will see newly updated statistics.  Once sampling	 is  disabled,
	      the  sampled  information	 is  kept until a new sample period is
	      started.	This allows multiple readouts.

	      Sample output from /proc/timer_stats:

   $ cat /proc/timer_stats
   Timer Stats Version: v0.3
   Sample period: 1.764 s
   Collection: active
     255,     0 swapper/3	 hrtimer_start_range_ns (tick_sched_timer)
      71,     0 swapper/1	 hrtimer_start_range_ns (tick_sched_timer)
      58,     0 swapper/0	 hrtimer_start_range_ns (tick_sched_timer)
       4,  1694 gnome-shell	 mod_delayed_work_on (delayed_work_timer_fn)
      17,     7 rcu_sched	 rcu_gp_kthread (process_timeout)
   ...
       1,  4911 kworker/u16:0	 mod_delayed_work_on (delayed_work_timer_fn)
      1D,  2522 kworker/0:0	 queue_delayed_work_on (delayed_work_timer_fn)
   1029 total events, 583.333 events/sec


	      The output columns are:

	      *	 a count of the number	of  events,  optionally	 (since	 Linux
		 2.6.23)  followed  by	the letter 'D' if this is a deferrable
		 timer;

	      *	 the PID of the process that initialized the timer;

	      *	 the name of the process that initialized the timer;

	      *	 the function where the timer was initialized; and

	      *	 (in parentheses) the callback	function  that	is  associated
		 with the timer.

       /proc/tty
	      Subdirectory  containing the pseudo-files and subdirectories for
	      tty drivers and line disciplines.

       /proc/uptime
	      This file contains two numbers: the uptime of the	 system	 (sec-
	      onds), and the amount of time spent in idle process (seconds).

       /proc/version
	      This string identifies the kernel version that is currently run-
	      ning.  It	 includes  the	contents  of  /proc/sys/kernel/ostype,
	      /proc/sys/kernel/osrelease  and  /proc/sys/kernel/version.   For
	      example:
	    Linux version 1.0.9 (quinlan@phaze) #1 Sat May 14 01:51:54 EDT 1994

       /proc/vmstat (since Linux 2.6.0)
	      This file displays various virtual memory statistics.  Each line
	      of  this	file  contains	a single name-value pair, delimited by
	      white space.  Some files are present only if the kernel was con-
	      figured  with  suitable  options.	  (In  some cases, the options
	      required for particular files have changed  across  kernel  ver-
	      sions,  so  they	are  not listed here.  Details can be found by
	      consulting the kernel source code.)  The following fields may be
	      present:

	      nr_free_pages (since Linux 2.6.31)

	      nr_alloc_batch (since Linux 3.12)

	      nr_inactive_anon (since Linux 2.6.28)

	      nr_active_anon (since Linux 2.6.28)

	      nr_inactive_file (since Linux 2.6.28)

	      nr_active_file (since Linux 2.6.28)

	      nr_unevictable (since Linux 2.6.28)

	      nr_mlock (since Linux 2.6.28)

	      nr_anon_pages (since Linux 2.6.18)

	      nr_mapped (since Linux 2.6.0)

	      nr_file_pages (since Linux 2.6.18)

	      nr_dirty (since Linux 2.6.0)

	      nr_writeback (since Linux 2.6.0)

	      nr_slab_reclaimable (since Linux 2.6.19)

	      nr_slab_unreclaimable (since Linux 2.6.19)

	      nr_page_table_pages (since Linux 2.6.0)

	      nr_kernel_stack (since Linux 2.6.32)
		     Amount of memory allocated to kernel stacks.

	      nr_unstable (since Linux 2.6.0)

	      nr_bounce (since Linux 2.6.12)

	      nr_vmscan_write (since Linux 2.6.19)

	      nr_vmscan_immediate_reclaim (since Linux 3.2)

	      nr_writeback_temp (since Linux 2.6.26)

	      nr_isolated_anon (since Linux 2.6.32)

	      nr_isolated_file (since Linux 2.6.32)

	      nr_shmem (since Linux 2.6.32)
		     Pages used by shmem and tmpfs.

	      nr_dirtied (since Linux 2.6.37)

	      nr_written (since Linux 2.6.37)

	      nr_pages_scanned (since Linux 3.17)

	      numa_hit (since Linux 2.6.18)

	      numa_miss (since Linux 2.6.18)

	      numa_foreign (since Linux 2.6.18)

	      numa_interleave (since Linux 2.6.18)

	      numa_local (since Linux 2.6.18)

	      numa_other (since Linux 2.6.18)

	      workingset_refault (since Linux 3.15)

	      workingset_activate (since Linux 3.15)

	      workingset_nodereclaim (since Linux 3.15)

	      nr_anon_transparent_hugepages (since Linux 2.6.38)

	      nr_free_cma (since Linux 3.7)
		     Number of free CMA (Contiguous Memory Allocator) pages.

	      nr_dirty_threshold (since Linux 2.6.37)

	      nr_dirty_background_threshold (since Linux 2.6.37)

	      pgpgin (since Linux 2.6.0)

	      pgpgout (since Linux 2.6.0)

	      pswpin (since Linux 2.6.0)

	      pswpout (since Linux 2.6.0)

	      pgalloc_dma (since Linux 2.6.5)

	      pgalloc_dma32 (since Linux 2.6.16)

	      pgalloc_normal (since Linux 2.6.5)

	      pgalloc_high (since Linux 2.6.5)

	      pgalloc_movable (since Linux 2.6.23)

	      pgfree (since Linux 2.6.0)

	      pgactivate (since Linux 2.6.0)

	      pgdeactivate (since Linux 2.6.0)

	      pgfault (since Linux 2.6.0)

	      pgmajfault (since Linux 2.6.0)

	      pgrefill_dma (since Linux 2.6.5)

	      pgrefill_dma32 (since Linux 2.6.16)

	      pgrefill_normal (since Linux 2.6.5)

	      pgrefill_high (since Linux 2.6.5)

	      pgrefill_movable (since Linux 2.6.23)

	      pgsteal_kswapd_dma (since Linux 3.4)

	      pgsteal_kswapd_dma32 (since Linux 3.4)

	      pgsteal_kswapd_normal (since Linux 3.4)

	      pgsteal_kswapd_high (since Linux 3.4)

	      pgsteal_kswapd_movable (since Linux 3.4)

	      pgsteal_direct_dma

	      pgsteal_direct_dma32 (since Linux 3.4)

	      pgsteal_direct_normal (since Linux 3.4)

	      pgsteal_direct_high (since Linux 3.4)

	      pgsteal_direct_movable (since Linux 2.6.23)

	      pgscan_kswapd_dma

	      pgscan_kswapd_dma32 (since Linux 2.6.16)

	      pgscan_kswapd_normal (since Linux 2.6.5)

	      pgscan_kswapd_high

	      pgscan_kswapd_movable (since Linux 2.6.23)

	      pgscan_direct_dma

	      pgscan_direct_dma32 (since Linux 2.6.16)

	      pgscan_direct_normal

	      pgscan_direct_high

	      pgscan_direct_movable (since Linux 2.6.23)

	      pgscan_direct_throttle (since Linux 3.6)

	      zone_reclaim_failed (since linux 2.6.31)

	      pginodesteal (since linux 2.6.0)

	      slabs_scanned (since linux 2.6.5)

	      kswapd_inodesteal (since linux 2.6.0)

	      kswapd_low_wmark_hit_quickly (since 2.6.33)

	      kswapd_high_wmark_hit_quickly (since 2.6.33)

	      pageoutrun (since Linux 2.6.0)

	      allocstall (since Linux 2.6.0)

	      pgrotated (since Linux 2.6.0)

	      drop_pagecache (since Linux 3.15)

	      drop_slab (since Linux 3.15)

	      numa_pte_updates (since Linux 3.8)

	      numa_huge_pte_updates (since Linux 3.13)

	      numa_hint_faults (since Linux 3.8)

	      numa_hint_faults_local (since Linux 3.8)

	      numa_pages_migrated (since Linux 3.8)

	      pgmigrate_success (since Linux 3.8)

	      pgmigrate_fail (since Linux 3.8)

	      compact_migrate_scanned (since Linux 3.8)

	      compact_free_scanned (since Linux 3.8)

	      compact_isolated (since Linux 3.8)

	      compact_stall (since Linux 2.6.35)
		     See   the	 kernel	  source  file	Documentation/vm/tran-
		     shuge.txt.

	      compact_fail (since Linux 2.6.35)
		     See  the  kernel	source	 file	Documentation/vm/tran-
		     shuge.txt.

	      compact_success (since Linux 2.6.35)
		     See   the	 kernel	  source  file	Documentation/vm/tran-
		     shuge.txt.

	      htlb_buddy_alloc_success (since Linux 2.6.26)

	      htlb_buddy_alloc_fail (since Linux 2.6.26)

	      unevictable_pgs_culled (since Linux 2.6.28)

	      unevictable_pgs_scanned (since Linux 2.6.28)

	      unevictable_pgs_rescued (since Linux 2.6.28)

	      unevictable_pgs_mlocked (since Linux 2.6.28)

	      unevictable_pgs_munlocked (since Linux 2.6.28)

	      unevictable_pgs_cleared (since Linux 2.6.28)

	      unevictable_pgs_stranded (since Linux 2.6.28)

	      thp_fault_alloc (since Linux 2.6.39)
		     See  the  kernel	source	 file	Documentation/vm/tran-
		     shuge.txt.

	      thp_fault_fallback (since Linux 2.6.39)
		     See   the	 kernel	  source  file	Documentation/vm/tran-
		     shuge.txt.

	      thp_collapse_alloc (since Linux 2.6.39)
		     See  the  kernel	source	 file	Documentation/vm/tran-
		     shuge.txt.

	      thp_collapse_alloc_failed (since Linux 2.6.39)
		     See   the	 kernel	  source  file	Documentation/vm/tran-
		     shuge.txt.

	      thp_split (since Linux 2.6.39)
		     See  the  kernel	source	 file	Documentation/vm/tran-
		     shuge.txt.

	      thp_zero_page_alloc (since Linux 3.8)
		     See   the	 kernel	  source  file	Documentation/vm/tran-
		     shuge.txt.

	      thp_zero_page_alloc_failed (since Linux 3.8)
		     See  the  kernel	source	 file	Documentation/vm/tran-
		     shuge.txt.

	      balloon_inflate (since Linux 3.18)

	      balloon_deflate (since Linux 3.18)

	      balloon_migrate (since Linux 3.18)

	      nr_tlb_remote_flush (since Linux 3.12)

	      nr_tlb_remote_flush_received (since Linux 3.12)

	      nr_tlb_local_flush_all (since Linux 3.12)

	      nr_tlb_local_flush_one (since Linux 3.12)

	      vmacache_find_calls (since Linux 3.16)

	      vmacache_find_hits (since Linux 3.16)

	      vmacache_full_flushes (since Linux 3.19)

       /proc/zoneinfo (since Linux 2.6.13)
	      This  file display information about memory zones.  This is use-
	      ful for analyzing virtual memory behavior.

NOTES
       Many strings (i.e., the environment and command line) are in the inter-
       nal  format, with subfields terminated by null bytes ('\0'), so you may
       find that things are more readable if you use od -c or tr  "\000"  "\n"
       to read them.  Alternatively, echo `cat <file>` works well.

       This manual page is incomplete, possibly inaccurate, and is the kind of
       thing that needs to be updated very often.

SEE ALSO
       cat(1), dmesg(1), find(1), free(1), ps(1), tr(1), uptime(1), chroot(2),
       mmap(2),	 readlink(2),  syslog(2), slabinfo(5), hier(7), namespaces(7),
       time(7), arp(8), hdparm(8), ifconfig(8), init(1),  lsmod(8),  lspci(8),
       mount(8), netstat(8), procinfo(8), route(8), sysctl(8)

       The Linux kernel source files: Documentation/filesystems/proc.txt Docu-
       mentation/sysctl/fs.txt,	 Documentation/sysctl/kernel.txt,   Documenta-
       tion/sysctl/net.txt, and Documentation/sysctl/vm.txt.

COLOPHON
       This  page  is  part of release 4.04 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest	  version     of     this    page,    can    be	   found    at
       http://www.kernel.org/doc/man-pages/.



Linux				  2015-12-05			       PROC(5)