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 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 which the kernel uses to
  20 support demand paging.  This pool is expanded with new swap files as load on
  21 the system increases, and contracted when the swapping resources are no
  22 longer needed.  The
  23 .Nm dynamic_pager
  24 daemon also provides a notification service for those applications which
  25 wish to receive notices when the external paging pool expands or contracts.
  26 .Sh OPTIONS
  27 .Bl -tag -width Ds
  28 .It Fl F
  29 The base name of the
  30 .Ar filename
  31 to use for the external paging files.  By default this is
  32 .Pa /private/var/vm/swapfile .
  33 .It Fl S
  34 The fixed
  35 .Ar filesize
  36 [in bytes] to use for the paging files.  By default
  37 .Nm dynamic_pager
  38 uses variable sized paging files, using larger sized files as paging demands
  39 increase.  The
  40 .Fl S ,
  41 .Fl H
  42 and
  43 .Fl L
  44 options disable that default and cause
  45 .Nm dynamic_pager
  46 to use a series of fixed sized external paging files.
  47 .It Fl H
  48 If there are less than
  49 .Ar high-water-trigger
  50 bytes free in the external paging files, the kernel will signal
  51 .Nm dynamic_pager
  52 to add a new external paging file.
  53 .It Fl L
  54 If there are more than
  55 .Ar low-water-trigger
  56 bytes free in the external paging files, the kernel will coalese in-use pages
  57 and signal
  58 .Nm dynamic_pager
  59 to discard an external paging file.
  60 .Ar Low-water-trigger
  61 must be greater than
  62 .Ar high-water-trigger
  63 +
  64 .Ar filesize .
  65 .It Fl P
  66 This option is currently unimplemented.
  67 .Sh FILES
  68 .Bl -tag -width /private/var/vp/swapfile* --compact
  69 .It Pa /private/var/vm/swapfile*
  70 Default external paging files.
  71 .Sh SEE ALSO
  72 .Xr macx_swapon 2 ,
  73 .Xr macx_swapoff 2 .