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NAME

       proc - process information pseudo-filesystem

DESCRIPTION

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

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

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

       /proc/[pid]/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
              containing 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
              configuration option is enabled.

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

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

              The following values may be written to the file:

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

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

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

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

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

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

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

              The  /proc/[pid]/clear_refs  file  is  present   only   if   the
              CONFIG_PROC_PAGE_MONITOR kernel configuration 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
              characters.  The command-line arguments appear in this file as a
              set  of  strings  separated by null bytes (''), 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 (''), 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
              containing  the  actual  pathname of the executed command.  This
              symbolic link can be dereferenced normally; attempting  to  open
              it  will open the executable.  You can even type /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
              symbolic link are not available if the main thread  has  already
              terminated (typically by calling pthread_exit(3)).

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

                  [device]:inode

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

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

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

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

                  type:[inode]

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

              For  file  descriptors  that  have no corresponding inode (e.g.,
              file  descriptors  produced  by   epoll_create(2),   eventfd(2),
              inotify_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
              (typically 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
              argument, but will not send their output to standard  output  if
              no  argument  is  supplied,  can  nevertheless  be  made  to use
              standard  input  or  standard  out  using  /proc/[pid]/fd.   For
              example,  assuming 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
              symbolically 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
              contents  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
              offset.   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
              measurement  for  each  of  the  process's  resource limits (see
              getrlimit(2)).  Up to and including Linux 2.6.35, this  file  is
              protected  to allow reading only by the real UID of the process.
              Since Linux 2.6.36, 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
              implemented 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
              offset field by looking at the Offset field in the  ELF  program
              headers (readelf -l).

              There are additional helpful pseudo-paths:

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

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

                   [vdso] The virtual dynamically linked shared object.

                   [heap] The process's heap.

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

              Under Linux 2.0 there is no field giving pathname.

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

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

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

              The numbers in  parentheses  are  labels  for  the  descriptions
              below:

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

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

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

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

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

              (6)  mount options: per-mount options.

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

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

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

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

              (11) super options: per-superblock options.

              Parsers  should  ignore  all   unrecognized   optional   fields.
              Currently 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
              "master:X"  field  is  present  and  not  the "propagate_from:X"
              field.

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

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

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

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

              The fields in each line are:

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

              (2)  The mount point within the filesystem tree.

              (3)  The filesystem type.

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

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

       /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
              terminate.

              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
              namespace 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
              terminate.

              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
              filesystem,  set  by  the chroot(2) system call.  This file is a
              symbolic link that points to the process's root  directory,  and
              behaves in the same way as exe, and fd/*.

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

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

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

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

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

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

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

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

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

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

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

              The   fields,  in  order,  with  their  proper  scanf(3)  format
              specifiers, 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,
                          measured     in     clock     ticks    (divide    by
                          sysconf(_SC_CLK_TCK)).

              priority %ld
                          (18)  (Explanation  for  Linux  2.6)  For  processes
                          running a real-time scheduling policy (policy below;
                          see  sched_setscheduler(2)),  this  is  the  negated
                          scheduling priority, minus one; that is, a number in
                          the range -2 to  -100,  corresponding  to  real-time
                          priorities  1  to 99.  For processes running under a
                          non-real-time scheduling policy,  this  is  the  raw
                          nice  value  (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
                          getrlimit(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
                          provide   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
                          provide  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
                          provide   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
                          provide  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  location  in  the
                          kernel   where   the   process   is  sleeping.   The
                          corresponding  symbolic  name  can   be   found   in
                          /proc/[pid]/wchan.

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

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

              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  filesystem  UIDs
                (GIDs).

              * FDSize: Number of file descriptor slots currently allocated.

              * Groups: Supplementary group list.

              * VmPeak: Peak virtual memory size.

              * VmSize: Virtual memory size.

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

              * 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
                capabilities(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]
              directories.  For attributes that are shared by all threads, the
              contents   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
              terminated (typically by calling pthread_exit(3)).

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

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

       /proc/bus
              Contains subdirectories for installed busses.

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

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

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

              The lines shown for each timer have the following meanings:

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

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

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

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

       /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
              configuring  the  kernel  (using  make  xconfig, make config, or
              similar).  The file contents are compressed; view or search them
              using  zcat(1)  and  zgrep(1).   As long as no changes have been
              made to the following file, the contents of /proc/config.gz  are
              the same as those provided by :

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

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

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

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

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

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

       /proc/driver
              Empty subdirectory.

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

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

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

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

       /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
              architectures,  at least, this also includes interrupts internal
              to the system (that is, not associated with a device  as  such),
              such   as   NMI   (nonmaskable   interrupt),  LOC  (local  timer
              interrupt), and for SMP systems, TLB (TLB flush interrupt),  RES
              (rescheduling  interrupt), CAL (remote function call interrupt),
              and possibly others.  Very easy  to  read  formatting,  done  in
              ASCII.

       /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
              different 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
              messages.

              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
              separated  by  a slash (/).  The first of these is the number of
              currently  runnable  kernel  scheduling   entities   (processes,
              threads).   The  value  after  the slash is the number of kernel
              scheduling entities that currently exist  on  the  system.   The
              fifth  field  is  the  PID of the process that was most recently
              created on the system.

       /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
              memory (both physical and swap) on the system  as  well  as  the
              shared  memory and buffers used by the kernel.  Each line of the
              file consists of a parameter name,  followed  by  a  colon,  the
              value of the parameter, and an option unit of measurement (e.g.,
              "kB").  The list below describes the  parameter  names  and  the
              format  specifier  required  to read the field value.  Except as
              noted below, all of the fields have been present since at  least
              Linux  2.6.0.   Some fileds are displayed only if the kernel was
              configured 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
                     everything  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
                     pressure.

              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 =
                             ([total RAM pages] - [total huge TLB pages]) *
                             overcommit_ratio / 100 + [total swap pages]

                     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
                     "committed"  to  by the VM and can be used at any time by
                     the  allocating  application.   With  strict   overcommit
                     enabled       on       the       system      (mode      2
                     /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_overcommit_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
              filesystems   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 documented 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
              structures 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
              kernel hash slot for the  socket,  the  "local_address"  is  the
              local  address  and  protocol number pair.  "St" is the internal
              status of the socket.  The "tx_queue"  and  "rx_queue"  are  the
              outgoing  and  incoming  data  queue  in  terms of kernel memory
              usage.  The "tr", "tm->when", and "rexmits" fields are not  used
              by  RAW.  The "uid" field holds the effective UID of the creator
              of the socket.

       /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
              kernel  hash  slot  for  the  socket, the "local_address" is the
              local address and port number pair.  The  "rem_address"  is  the
              remote address and port number pair (if connected).  "St" is the
              internal status of the socket.  The  "tx_queue"  and  "rx_queue"
              are  the  outgoing  and  incoming  data queue in terms of kernel
              memory usage.  The "tr", "tm->when", and "rexmits"  fields  hold
              internal  information  of  the  kernel socket state and are only
              useful for debugging.  The "uid" field holds the  effective  UID
              of the creator of the socket.

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

 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
              datagram  sockets are not yet supported in the kernel).  "St" is
              the internal state of the socket and Path is the bound path  (if
              any) of the socket.

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

       /proc/pci
              This is a  listing  of  all  PCI  devices  found  during  kernel
              initialization 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
              CONFIG_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
              profile=1 command-line  option.   It  exposes  kernel  profiling
              information  in  a  binary  format  for  use  by readprofile(1).
              Writing  (e.g.,  an  empty  string)  to  this  file  resets  the
              profiling  counters;  on  some  architectures,  writing a binary
              integer "profiling multiplier"  of  size  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
              subsystem 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
              currently 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
              registered at least one SCSI HBA.  Every directory contains  one
              file  per  registered  host.  Every host-file is named after the
              number the host was assigned during initialization.

              Reading  these  files  will  usually  show   driver   and   host
              configuration, statistics, and so on.

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

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

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

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

              See slabinfo(5) for details.

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

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

                     user   (1) Time spent in user mode.

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

                     system (3) Time spent in system mode.

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

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

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

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

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

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

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

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

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

              intr 1462898
                     This line shows counts of interrupts serviced since  boot
                     time,  for  each  of the possible system interrupts.  The
                     first column is the total  of  all  interrupts  serviced;
                     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
              filesystem, and the (deprecated) sysctl(2) system call.

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

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

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

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

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

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

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

              * nr_unused is the number of unused dentries.

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

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

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

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

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

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

       /proc/sys/fs/file-max
              This  file  defines  a  system-wide  limit on the number of open
              files for all processes.  (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
              increasing 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.

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

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

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

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

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

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

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

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

       /proc/sys/fs/inotify (since Linux 2.6.13)
              This     directory     contains     files     max_queued_events,
              max_user_instances,  and  max_user_watches,  that can be used to
              limit the amount  of  kernel  memory  consumed  by  the  inotify
              interface.  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
              signal  to  that  process  notifying  it that another process is
              waiting to open the file.  If the lease holder does  not  remove
              or  downgrade  the  lease  within  this grace period, the kernel
              forcibly breaks the lease.

       /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  filesystems support only
              16-bit UIDs and GIDs, although in Linux UIDs  and  GIDs  are  32
              bits.   When  one  of  these  filesystems is mounted with writes
              enabled, any UID or GID that would exceed 65535 is translated to
              the overflow value before being written to disk.

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

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

              *  The caller has the CAP_FOWNER capability.

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

              *  All of the following conditions are true:

                  ·  the target is a regular file;

                  ·  the target file does not have its set-user-ID  permission
                     bit enabled;

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

                  ·  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
              "pinning" 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  filesystem UID of the process following the link matches
                 the owner  (UID)  of  the  symbolic  link  (as  described  in
                 credentials(7),  a  process's  filesystem UID is normally the
                 same as its effective UID);

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

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

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

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

       /proc/sys/fs/suid_dumpable (since Linux 2.6.13)
              The value in this file determines whether core  dump  files  are
              produced   for   set-user-ID   or   otherwise  protected/tainted
              binaries.  Three different integer values can be specified:

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

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

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

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

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

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

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

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

       /proc/sys/kernel/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
              capability 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
              keyboard.  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,
              without even syncing its dirty buffers.  Note:  when  a  program
              (like  dosemu)  has the keyboard in "raw" mode, the ctrl-alt-del
              is intercepted by the program before it ever reaches the  kernel
              tty  layer, and it's up to the program to decide what to do with
              it.

       /proc/sys/kernel/dmesg_restrict (since Linux 2.6.37)
              The value in this file determines  who  can  see  kernel  syslog
              contents.   A  value  of 0 in this file imposes no restrictions.
              If the value is 1, only privileged users  can  read  the  kernel
              syslog.   (See  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
              hostname  "darkstar"  and  DNS  (Internet  Domain  Name  Server)
              domainname  "frop.org", not to be confused with the NIS (Network
              Information Service) or YP (Yellow Pages) domainname.  These two
              domain   names   are  in  general  different.   For  a  detailed
              discussion see the 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
              PowerPC         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
              CONFIG_MODULES option enabled.

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

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

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

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

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

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

       /proc/sys/kernel/pid_max (since Linux 2.5.34)
              This  file  specifies the value at which PIDs wrap around (i.e.,
              the value in this file is one greater  than  the  maximum  PID).
              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_message_loglevel,       minimum_console_level,       and
              default_console_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
              console_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
              currently in use.

       /proc/sys/kernel/random
              This  directory  contains  various  parameters  controlling  the
              operation  of  the  file /dev/random.  See random(4) for further
              information.

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

       /proc/sys/kernel/real-root-dev
              This  file  is  documented  in  the  Linux  kernel  source  file
              Documentation/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
              possible  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
              System 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
              nonstandard and could  also  break  existing  applications,  the
              default value in this file is 0.  Only set this file to 1 if you
              have a good understanding of the semantics of  the  applications
              using System V shared memory on your system.

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

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

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

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

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

              This file is  present  only  if  the  CONFIG_MAGIC_SYSRQ  kernel
              configuration  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
              filesystem (NFS).  On some systems, it is not present.

       /proc/sys/vm
              This  directory  contains  files  for  memory management tuning,
              buffer 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.  This can be useful  for  memory  management  testing  and
              performing  reproducible filesystem benchmarks.  Because writing
              to this file causes the benefits of caching to be lost,  it  can
              degrade overall system performance.

              To free pagecache, use:

                  echo 1 > /proc/sys/vm/drop_caches

              To free dentries and inodes, use:

                  echo 2 > /proc/sys/vm/drop_caches

              To free pagecache, dentries and inodes, use:

                  echo 3 > /proc/sys/vm/drop_caches

              Because  writing  to this file is a nondestructive operation and
              dirty objects are not freeable,  the  user  should  run  sync(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
              handled by the kernel is detected in the background by hardware.
              In some cases (like the page still having a valid copy on disk),
              the  kernel  will  handle  the  failure  transparently   without
              affecting any applications.  But if there is no other up-to-date
              copy of the data, it will kill processes  to  prevent  any  data
              corruptions from propagating.

              The file has one of the following values:

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

              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_MEMORY_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_MEMORY_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
              possibly 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_allocating_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
              getting  a  process  "OOM-killed".   Under Linux 2.4 any nonzero
              value implies mode 1.  In mode 2 (available  since  Linux  2.6),
              the  total virtual address space on the system is limited to (SS
              + RAM*(r/100)), where SS is the size of the swap space, and  RAM
              is the size of the physical memory, and r is the contents of the
              file /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
              situation.

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

              If  this  file  is  set to the value 1, then the kernel normally
              panics when out-of-memory happens.  However, if a process limits
              allocations  to  certain  nodes  using memory policies (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
              function 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
              Documentation/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
              (seconds),  and  the  amount  of  time  spent  in  idle  process
              (seconds).

       /proc/version
              This string identifies the  kernel  version  that  is  currently
              running.   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
              useful for analyzing virtual memory behavior.

NOTES

       Many strings (i.e., the  environment  and  command  line)  are  in  the
       internal format, with subfields terminated by null bytes (''), so you
       may find that things are more readable if you use od -c  or  tr  ""
       "
" 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),
       netstat(8), procinfo(8), route(8), sysctl(8)

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

COLOPHON

       This  page  is  part of release 3.65 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/.



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