[apple/system_cmds.git] / dynamic_pager.tproj / dynamic_pager.8

.\" Copyright (c) 2003 Apple Computer, Inc.  All rights reserved.
.\"
.Dd July 8, 2003
.Dt dynamic_pager 8
.Os "Mac OS X"
.Sh NAME
.Nm dynamic_pager
.Nd dynamic pager external storage manager
.Sh SYNOPSIS
.Nm dynamic_pager
.Op Fl F Ar filename
.Op Fl S Ar filesize
.Op Fl H Ar high-water-trigger
.Op Fl L Ar low-water-trigger
.Op Fl P Ar priority
.Sh DESCRIPTION
The
.Nm dynamic_pager
daemon manages a pool of external swap files which the kernel uses to
support demand paging.  This pool is expanded with new swap files as load on
the system increases, and contracted when the swapping resources are no
longer needed.  The
.Nm dynamic_pager
daemon also provides a notification service for those applications which
wish to receive notices when the external paging pool expands or contracts.
.Sh OPTIONS
.Bl -tag -width Ds
.It Fl F
The base name of the
.Ar filename
to use for the external paging files.  By default this is
.Pa /private/var/vm/swapfile .
.It Fl S
The fixed
.Ar filesize
[in bytes] to use for the paging files.  By default
.Nm dynamic_pager
uses variable sized paging files, using larger sized files as paging demands
increase.  The
.Fl S ,
.Fl H
and
.Fl L
options disable that default and cause
.Nm dynamic_pager
to use a series of fixed sized external paging files.
.It Fl H
If there are less than
.Ar high-water-trigger
bytes free in the external paging files, the kernel will signal
.Nm dynamic_pager
to add a new external paging file.
.It Fl L
If there are more than
.Ar low-water-trigger
bytes free in the external paging files, the kernel will coalese in-use pages
and signal
.Nm dynamic_pager
to discard an external paging file.
.Ar Low-water-trigger
must be greater than
.Ar high-water-trigger
+
.Ar filesize .
.It Fl P
This option is currently unimplemented.
.Sh FILES
.Bl -tag -width /private/var/vp/swapfile* --compact
.It Pa /private/var/vm/swapfile*
Default external paging files.
.Sh SEE ALSO
.Xr macx_swapon 2 ,
.Xr macx_swapoff 2 .
Commit	Line	Data
c3a08f59 A	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 .