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 dynamic pager external storage manager
   9 .Sh SYNOPSIS
  10 .Nm dynamic_pager
  11 .Op Fl E
  12 .Op Fl F Ar filename
  13 .Op Fl S Ar filesize
  14 .Op Fl H Ar high-water-trigger
  15 .Op Fl L Ar low-water-trigger
  16 .Op Fl P Ar priority
  17 .Sh DESCRIPTION
  18 The
  19 .Nm dynamic_pager
  20 daemon manages a pool of external swap files which the kernel uses to
  21 support demand paging.  This pool is expanded with new swap files as load on
  22 the system increases, and contracted when the swapping resources are no
  23 longer needed.  The
  24 .Nm dynamic_pager
  25 daemon also provides a notification service for those applications which
  26 wish to receive notices when the external paging pool expands or contracts.
  27 .Sh OPTIONS
  28 .Bl -tag -width Ds
  29 .It Fl E
  30 Encrypt the data in the swap files.
  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 .It Fl S
  37 The fixed
  38 .Ar filesize
  39 [in bytes] to use for the paging files.  By default
  40 .Nm dynamic_pager
  41 uses variable sized paging files, using larger sized files as paging demands
  42 increase.  The
  43 .Fl S ,
  44 .Fl H
  45 and
  46 .Fl L
  47 options disable that default and cause
  48 .Nm dynamic_pager
  49 to use a series of fixed sized external paging files.
  50 .It Fl H
  51 If there are less than
  52 .Ar high-water-trigger
  53 bytes free in the external paging files, the kernel will signal
  54 .Nm dynamic_pager
  55 to add a new external paging file.
  56 .It Fl L
  57 If there are more than
  58 .Ar low-water-trigger
  59 bytes free in the external paging files, the kernel will coalese in-use pages
  60 and signal
  61 .Nm dynamic_pager
  62 to discard an external paging file.
  63 .Ar Low-water-trigger
  64 must be greater than
  65 .Ar high-water-trigger
  66 +
  67 .Ar filesize .
  68 .It Fl P
  69 This option is currently unimplemented.
  70 .El
  71 .Sh FILES
  72 .Bl -tag -width /private/var/vp/swapfile* -compact
  73 .It Pa /private/var/vm/swapfile*
  74 Default external paging files.
  75 .El