dynamic_pager.tproj/dynamic_pager.8

   1 .\" Copyright (c) 2003 Apple Computer, Inc.  All rights reserved.
   2 .\"
   3 .Dd July 8, 2003
   4 .Dt dynamic_pager 8
   5 .Os "Mac OS X"
   6 .Sh NAME
   7 .Nm dynamic_pager
   8 .Nd external storage manager for dynamic pager
   9 .Sh SYNOPSIS
  10 .Nm dynamic_pager
  11 .Op Fl F Ar filename
  12 .Op Fl S Ar filesize
  13 .Op Fl H Ar high-water-trigger
  14 .Op Fl L Ar low-water-trigger
  15 .Op Fl P Ar priority
  16 .Sh DESCRIPTION
  17 The
  18 .Nm dynamic_pager
  19 daemon manages a pool of external swap files
  20 which the kernel uses to support demand paging.
  21 This pool is expanded with new swap files
  22 as load on the system increases.
  23 It is contracted when the swapping resources are no longer needed.  The
  24 .Nm dynamic_pager
  25 daemon also provides a notification service
  26 for those applications which wish to receive notices
  27 when the external paging pool expands or contracts.
  28 .Sh OPTIONS
  29 .Bl -tag -width Ds
  30 .\" ==========
  31 .It Fl F
  32 The base name of the
  33 .Ar filename
  34 to use for the external paging files.  By default this is
  35 .Pa /private/var/vm/swapfile .
  36 .\" ==========
  37 .It Fl H
  38 If there are less than
  39 .Ar high-water-trigger
  40 bytes free in the external paging files, the kernel will signal
  41 .Nm dynamic_pager
  42 to add a new external paging file.
  43 .\" ==========
  44 .It Fl L
  45 If there are more than
  46 .Ar low-water-trigger
  47 bytes free in the external paging files, the kernel will coalese in-use pages
  48 and signal
  49 .Nm dynamic_pager
  50 to discard an external paging file.
  51 .Ar Low-water-trigger
  52 must be greater than
  53 .Ar high-water-trigger
  54 +
  55 .Ar filesize .
  56 .\" ==========
  57 .It Fl P
  58 This option is currently unimplemented.
  59 .\" ==========
  60 .It Fl S
  61 The fixed
  62 .Ar filesize
  63 [in bytes] to use for the paging files.  By default
  64 .Nm dynamic_pager
  65 uses variable sized paging files, using larger sized files as paging demands
  66 increase.  The
  67 .Fl S ,
  68 .Fl H
  69 and
  70 .Fl L
  71 options disable that default and cause
  72 .Nm dynamic_pager
  73 to use a series of fixed sized external paging files.
  74 .El
  75 .Sh FILES
  76 .Bl -tag -width /Library/Preferences/com.apple.virtualMemory.plist -compact
  77 .It Pa /private/var/vm/swapfile*
  78 Default external paging files.
  79 .It Pa /Library/Preferences/com.apple.virtualMemory.plist
  80 Configuration file.
  81 .El
  82 .Sh XML PROPERTY LIST KEYS
  83 The following keys can be specified in the configuration file.  Please see
  84 .Xr plist 5
  85 for more information about property list files.
  86 .Pp
  87 .Bl -ohang
  88 .It Sy UseEncryptedSwap <boolean>
  89 This optional key activates encrypted swap (aka Secure VM), so that all data is encrypted before being written to a swap file.  The default is on for portable computers and off for other computers.
  90 .El