[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 E
.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 E
Encrypt the data in the swap files.
.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.
.El
.Sh FILES
.Bl -tag -width /private/var/vp/swapfile* -compact
.It Pa /private/var/vm/swapfile*
Default external paging files.
.El
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
2fc1e207	11	.Op Fl E
c3a08f59 A	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
2fc1e207 A	29	.It Fl E
2fc1e207 A	30	Encrypt the data in the swap files.
c3a08f59 A	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.
83f6dbe8	70	.El
c3a08f59	71	.Sh FILES
83f6dbe8	72	.Bl -tag -width /private/var/vp/swapfile* -compact
c3a08f59 A	73	.It Pa /private/var/vm/swapfile*
c3a08f59 A	74	Default external paging files.
83f6dbe8	75	.El