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

NAME
       proc - process information pseudo-file system

DESCRIPTION
       The proc	file system is a pseudo-file system which is used as an	inter-
       face 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.

       The following outline gives a quick tour	through	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]/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.

       /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]/cmdline
	      This 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 charac-
	      ters.  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]/coredump_filter (since kernel 2.6.23)
	      See core(5).

       /proc/[pid]/cpuset (since kernel	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 as is	being run  by  process
	      [pid].   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, etc.

	      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 kernel 2.6.22)
	      This  is a subdirectory containing one entry for each file which
	      the process has open, named by its file  descriptor.   The  con-
	      tents  of	 each file can be read to obtain information about the
	      corresponding file descriptor, for example:

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

	      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 files	in this	directory are readable only by	the  owner  of
	      the process.

       /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]/limits (since kernel	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.

       /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 file system (see
		   stat(2)).

	      (4)  root: root of the mount within the file system.

	      (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)  file	  system  type:	 name  of  file	 system	 in  the  form
		   "type[.subtype]".

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

	      (11) super options: per-super block 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 file systems 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 file system 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.

       /proc/[pid]/mountstats (since Linux 2.6.17)
	      This  file exports information (statistics, configuration	infor-
	      mation) about the	mount points  in  the  process's  name	space.
	      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 file system tree.

	      (3)  The file system type.

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

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

       /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 information
	      about namespaces,	see clone(2).

       /proc/[pid]/ns/ipc (since Linux 3.0)
	      Bind mounting this file (see mount(2)) to	somewhere else in  the
	      filesystem  keeps	 the IPC namespace of the process specified by
	      pid alive	even if	all processes currently	in the namespace  ter-
	      minate.

	      Opening this file	returns	a file handle for the IPC namespace of
	      the process specified by pid.  As	long as	this  file  descriptor
	      remains  open,  the IPC namespace	will remain alive, even	if all
	      processes	in the namespace terminate.  The file  descriptor  can
	      be passed	to setns(2).

       /proc/[pid]/ns/net (since Linux 3.0)
	      Bind  mounting this file (see mount(2)) to somewhere else	in the
	      filesystem keeps the network namespace of	the process  specified
	      by pid alive even	if all processes in the	namespace terminate.

	      Opening  this  file returns a file handle	for the	network	names-
	      pace of the process specified by pid.   As  long	as  this  file
	      descriptor  remains  open,  the  network	namespace  will	remain
	      alive, even if all processes in the  namespace  terminate.   The
	      file descriptor can be passed to setns(2).

       /proc/[pid]/ns/uts (since Linux 3.0)
	      Bind  mounting this file (see mount(2)) to somewhere else	in the
	      filesystem keeps the UTS namespace of the	process	 specified  by
	      pid  alive even if all processes currently in the	namespace ter-
	      minate.

	      Opening this file	returns	a file handle for the UTS namespace of
	      the  process  specified by pid.  As long as this file descriptor
	      remains open, the	UTS namespace will remain alive, even  if  all
	      processes	 in  the namespace terminate.  The file	descriptor can
	      be passed	to setns(2).

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

	      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]/smaps (since	Linux 2.6.14)
	      This file	shows memory consumption for  each  of	the  process's
	      mappings.	  For each of mappings there is	a series of lines such
	      as the following:

		  08048000-080bc000 r-xp 00000000 03:02	13130	   /bin/bash
		  Size:		      464 kB
		  Rss:		      424 kB
		  Shared_Clean:	      424 kB
		  Shared_Dirty:		0 kB
		  Private_Clean:	0 kB
		  Private_Dirty:	0 kB

	      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, the number of	clean and dirty	shared
	      pages in the mapping, and	the number of clean and	dirty  private
	      pages in the mapping.

	      This file	is present only	if the CONFIG_MMU kernel configuration
	      option is	enabled.

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

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

	      pid %d	  (1) The process ID.

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

	      state %c	  (3) One character from the string "RSDZTW"  where  R
			  is  running, S is sleeping in	an interruptible wait,
			  D is waiting in uninterruptible  disk	 sleep,	 Z  is
			  zombie,  T is	traced or stopped (on a	signal), and W
			  is paging.

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

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

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

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

	      tpgid %d	  (8)  The  ID	of the foreground process group	of the
			  controlling terminal of the process.

	      flags %u (%lu before Linux 2.6.22)
			  (9) The kernel flags word of the process.   For  bit
			  meanings,  see  the PF_* defines in the Linux	kernel
			  source file include/linux/sched.h.   Details	depend
			  on the kernel	version.

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

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

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

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

	      utime %lu	  (14) 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 calculations.

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

	      cutime %ld  (16) 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).

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

	      priority %ld
			  (18) (Explanation for	Linux 2.6) For processes  run-
			  ning	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  (setpriority(2))	 as represented	in the
			  kernel.  The kernel stores nice values as numbers in
			  the range 0 (high) to	39 (low), corresponding	to the
			  user-visible nice range of -20 to 19.

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

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

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

	      itrealvalue %ld
			  (21) 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.

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

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

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

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

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

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

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

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

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

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

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

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

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

	      wchan %lu	  (35)	This  is the "channel" in which	the process is
			  waiting.  It is the address of a  system  call,  and
			  can be looked	up in a	namelist if you	need a textual
			  name.	 (If you have an  up-to-date  /etc/psdatabase,
			  then try ps -l to see	the WCHAN field	in action.)

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

	      cnswap %lu  (37) Cumulative nswap	for child processes (not main-
			  tained).

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

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

	      rt_priority %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
			  (40) Real-time scheduling priority, a	number in  the
			  range	 1 to 99 for processes scheduled under a real-
			  time policy, or 0, for non-real-time processes  (see
			  sched_setscheduler(2)).

	      policy %u	(since Linux 2.5.19; was %lu before Linux 2.6.22)
			  (41)	Scheduling policy (see sched_setscheduler(2)).
			  Decode using the SCHED_* constants in	linux/sched.h.

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

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

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

       /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
		  VmHWM:      7572 kB
		  VmRSS:      6316 kB
		  VmData:     5224 kB
		  VmStk:	88 kB
		  VmExe:       572 kB
		  VmLib:      1708 kB
		  VmPTE:	20 kB
		  Threads:	  1
		  SigQ:	  0/3067
		  SigPnd: 0000000000000000
		  ShdPnd: 0000000000000000
		  SigBlk: 0000000000010000
		  SigIgn: 0000000000384004
		  SigCgt: 000000004b813efb
		  CapInh: 0000000000000000
		  CapPrm: 0000000000000000
		  CapEff: 0000000000000000
		  CapBnd: ffffffffffffffff
		  Cpus_allowed:	  00000001
		  Cpus_allowed_list:	  0
		  Mems_allowed:	  1
		  Mems_allowed_list:	  0
		  voluntary_ctxt_switches:	  150
		  nonvoluntary_ctxt_switches:	  545

	      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  file  system  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)).

	      *	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).

	      *	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  kernel  2.6.26,  see
		capabilities(7)).

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

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

       /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), zgrep(1), etc.  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/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 file systems which are  supported  by  the
	      kernel,  namely file systems which were compiled into the	kernel
	      or  whose	 kernel	 modules  are  currently  loaded.   (See  also
	      filesystems(5).)	 If a file system is marked with "nodev", this
	      means that it does not require a	block  device  to  be  mounted
	      (e.g., virtual file system, network file system).

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

       /proc/fs
	      Empty subdirectory.

       /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/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 fileds 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 mmaped, 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)
		     Based  on	the  overcommit	ratio ('vm.overcommit_ratio'),
		     this is the total amount of  memory  currently  available
		     to	 be allocated on the system.  This limit is adhered to
		     only if strict overcommit accounting is enabled  (mode  2
		     in	 /proc/sys/vm/overcommit_ratio).   The	CommitLimit is
		     calculated	using the following formula:

			 CommitLimit = (overcommit_ratio  *  Physical  RAM)  +
		     Swap

		     For example, on a system with 1GB of physical RAM and 7GB
		     of	swap with  a  overcommit_ratio	of  30,	 this  formula
		     yields a CommitLimit of 7.3GB.  For more details, see the
		     memory overcommit documentation in	the kernel source file
		     Documentation/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  "commit-
		     ted"  to  by  the	VM  and	can be used at any time	by the
		     allocating	application.  With strict  overcommit  enabled
		     on	 the  system  (mode 2 /proc/sys/vm/overcommit_memory),
		     allocations which would exceed the	CommitLimit  (detailed
		     above)  will  not	be  permitted.	 This is useful	if one
		     needs to guarantee	that processes will not	 fail  due  to
		     lack  of  memory  once  that memory has been successfully
		     allocated.

	      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 file  sys-
	      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 only useful 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

	      Here  "Num"  is  the kernel table	slot number, "RefCount"	is the
	      number of	users of the socket, "Protocol"	is currently always 0,
	      "Flags"  represent  the internal kernel flags holding the	status
	      of the socket.  Currently, type is always	"1" (UNIX domain data-
	      gram  sockets are	not yet	supported in the kernel).  "St"	is the
	      internal state of	the socket and Path is the bound path (if any)
	      of the socket.

       /proc/partitions
	      Contains	major  and  minor numbers of each partition as well as
	      number of	blocks and 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,	etc.

	      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  file
	      system,  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;
		     each subsequent column is	the  total  for	 a  particular
		     interrupt.

	      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
	      file system, and the (deprecated)	sysctl(2) system call.

       /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 file	systems.

       /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.  (See also setrlimit(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 increas-
	      ing this value:

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

	      The kernel constant NR_OPEN imposes an upper limit on the	 value
	      that may be placed in file-max.

	      If  you  increase	 /proc/sys/fs/file-max,	 be  sure  to increase
	      /proc/sys/fs/inode-max  to  3-4	times	the   new   value   of
	      /proc/sys/fs/file-max, or	you will run out of inodes.

	      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
	      This file	contains the maximum number of in-memory  inodes.   On
	      some (2.4) systems, it may not be	present.  This value should be
	      3-4 times	larger than the	value in 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.

       /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.  nr_inodes is the number of
	      inodes the system	has allocated.	This can be slightly more than
	      inode-max	 because Linux allocates them one page full at a time.
	      nr_free_inodes represents	the number of free inodes.   preshrink
	      is  nonzero  when	the nr_inodes >	inode-max and the system needs
	      to prune the inode list instead of allocating more.

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

       /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-
	      iour  before  Linux  3.6).   When	the value in this file is 1, a
	      hard link	can be created to a target file	only  if  one  of  the
	      following	conditions is true:

	      *	 The caller has	the CAP_FOWNER capability.

	      *	 The  file system UID of the process creating the link matches
		 the owner (UID) of the	target file (as	described  in  creden-
		 tials(7), a process's file system 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  permission
		     bit enabled;

		  o  the  target  file does not	have both its set-group-ID and
		     group-executable permission 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 behaviour
	      before Linux 3.6).  When the value in this file is  1,  symbolic
	      links are	followed only in the following circumstances:

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

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

	      *	 the symbolic link and 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 determines	whether	core  dump  files  are
	      produced	for  set-user-ID  or otherwise protected/tainted bina-
	      ries.  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 file system 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 file systems the kernel can have.
	      You need increase	only super-max if you need to mount more  file
	      systems than the current value in	super-max allows you to.

       /proc/sys/fs/super-nr
	      This file	contains the number of file systems 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	values
	      control its behavior.  If	free space on file  system  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/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(8) program  to  handle  a  graceful
	      restart.	 When the value	is greater than	zero, Linux's reaction
	      to a Vulcan Nerve	Pinch (tm) will	be an immediate	reboot,	 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
	      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.

       /proc/sys/kernel/msgmnb
	      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/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 autoreboot
	      after  this number of seconds.  When you use the software	watch-
	      dog 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).
	      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
	      The four values in this file are console_loglevel,  default_mes-
	      sage_loglevel,	 minimum_console_level,	   and	  default_con-
	      sole_loglevel.  These values influence  printk()	behavior  when
	      printing or logging error	messages.  See syslog(2) for more info
	      on the different loglevels.  Messages  with  a  higher  priority
	      than  console_loglevel will be printed to	the console.  Messages
	      without an explicit  priority  will  be  printed	with  priority
	      default_message_level.   minimum_console_loglevel	is the minimum
	      (highest)	 value	to  which   console_loglevel   can   be	  set.
	      default_console_loglevel	 is   the   default   value  for  con-
	      sole_loglevel.

       /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/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/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
	      This file	contains the system-wide limit on the total number  of
	      pages of System V	shared memory.

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

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

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

       /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.

       /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/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
	      file system (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/drop_caches	(since Linux 2.6.16)
	      Writing  to  this	 file  causes the kernel to drop clean caches,
	      dentries and inodes from memory, causing that memory  to	become
	      free.

	      To  free	pagecache,  use	 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 this is a	nondestructive operation and dirty objects are
	      not freeable, the	user should run	sync(8)	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_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 on	the system is limited to (SS +
	      RAM*(r/100)), where SS is	the size of the	swap space, and	RAM is
	      the  size	 of  the physical memory, and r	is the contents	of the
	      file /proc/sys/vm/overcommit_ratio.

       /proc/sys/vm/overcommit_ratio
	      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/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)
	      This file	displays various virtual memory	statistics.

       /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), time(7), arp(8),
       hdparm(8),  ifconfig(8),	 init(8),  lsmod(8),  lspci(8),	mount(8), net-
       stat(8),	procinfo(8), route(8), sysctl(8)

       The Linux kernel	source files:  Documentation/filesystems/proc.txt  and
       Documentation/sysctl/vm.txt.

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found	at http://www.kernel.org/doc/man-pages/.

Linux				  2013-08-01			       PROC(5)

NAME | DESCRIPTION | NOTES | SEE ALSO | COLOPHON

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