168 lines
4.6 KiB
Groff
168 lines
4.6 KiB
Groff
.\"
|
|
.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice(s), this list of conditions and the following disclaimer as
|
|
.\" the first lines of this file unmodified other than the possible
|
|
.\" addition of one or more copyright notices.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice(s), this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
|
|
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
|
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
|
|
.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
|
|
.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
|
|
.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
|
|
.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
|
|
.\" DAMAGE.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd December 1, 2001
|
|
.Dt VM_PAGE_BITS 9
|
|
.Os
|
|
.Sh NAME
|
|
.Nm vm_page_bits ,
|
|
.Nm vm_page_set_validclean ,
|
|
.Nm vm_page_clear_dirty ,
|
|
.Nm vm_page_set_invalid ,
|
|
.Nm vm_page_zero_invalid ,
|
|
.Nm vm_page_is_valid ,
|
|
.Nm vm_page_test_dirty ,
|
|
.Nm vm_page_dirty ,
|
|
.Nm vm_page_undirty
|
|
.Nd "manage page clean and dirty bits"
|
|
.Sh SYNOPSIS
|
|
.In sys/param.h
|
|
.In vm/vm.h
|
|
.In vm/vm_page.h
|
|
.Ft int
|
|
.Fn vm_page_bits "int base" "int size"
|
|
.Ft void
|
|
.Fn vm_page_set_validclean "vm_page_t m" "int base" "int size"
|
|
.Ft void
|
|
.Fn vm_page_clear_dirty "vm_page_t m" "int base" "int size"
|
|
.Ft void
|
|
.Fn vm_page_set_invalid "vm_page_t m" "int base" "int size"
|
|
.Ft void
|
|
.Fn vm_page_zero_invalid "vm_page_t m" "boolean_t setvalid"
|
|
.Ft int
|
|
.Fn vm_page_is_valid "vm_page_t m" "int base" "int size"
|
|
.Ft void
|
|
.Fn vm_page_test_dirty "vm_page_t m"
|
|
.Ft void
|
|
.Fn vm_page_dirty "vm_page_t m"
|
|
.Ft void
|
|
.Fn vm_page_undirty "vm_page_t m"
|
|
.Sh DESCRIPTION
|
|
.Fn vm_page_bits
|
|
calculates the bits representing the
|
|
.Dv DEV_BSIZE
|
|
range of bytes between
|
|
.Fa base
|
|
and
|
|
.Fa size .
|
|
The byte range is expected to be within a single page, and if
|
|
.Fa size
|
|
is zero, no bits will be set.
|
|
.Pp
|
|
.Fn vm_page_set_validclean
|
|
flags the byte range between
|
|
.Fa base
|
|
and
|
|
.Fa size
|
|
as valid and clean.
|
|
The range is expected to be
|
|
.Dv DEV_BSIZE
|
|
aligned and no larger than
|
|
.Dv PAGE_SIZE .
|
|
If it is not properly aligned, any unaligned chunks of the
|
|
.Dv DEV_BSIZE
|
|
blocks at the beginning and end of the range will be zeroed.
|
|
.Pp
|
|
If
|
|
.Fa base
|
|
is zero and
|
|
.Fa size
|
|
is one page, the modified bit in the page map is cleared; as well,
|
|
the
|
|
.Dv VPO_NOSYNC
|
|
flag is cleared.
|
|
.Pp
|
|
.Fn vm_page_clear_dirty
|
|
clears the dirty bits within a page in the range between
|
|
.Fa base
|
|
and
|
|
.Fa size .
|
|
The bits representing the range are calculated by calling
|
|
.Fn vm_page_bits .
|
|
.Pp
|
|
.Fn vm_page_set_invalid
|
|
clears the bits in both the valid and dirty flags representing
|
|
the
|
|
.Dv DEV_BSIZE
|
|
blocks between
|
|
.Fa base
|
|
and
|
|
.Fa size
|
|
in the page.
|
|
The bits are calculated by calling
|
|
.Fn vm_page_bits .
|
|
As well as clearing the bits within the page, the generation
|
|
number within the object holding the page is incremented.
|
|
.Pp
|
|
.Fn vm_page_zero_invalid
|
|
zeroes all of the blocks within the page that are currently
|
|
flagged as invalid.
|
|
If
|
|
.Fa setvalid
|
|
is
|
|
.Dv TRUE ,
|
|
all of the valid bits within the page are set.
|
|
.Pp
|
|
In some cases, such as NFS, the valid bits cannot be set
|
|
in order to maintain cache consistency.
|
|
.Pp
|
|
.Fn vm_page_is_valid
|
|
checks to determine if the all of the
|
|
.Dv DEV_BSIZE
|
|
blocks between
|
|
.Fa base
|
|
and
|
|
.Fa size
|
|
of the page are valid.
|
|
If
|
|
.Fa size
|
|
is zero and the page is entirely invalid
|
|
.Fn vm_page_is_valid
|
|
will return
|
|
.Dv TRUE ,
|
|
in all other cases a size of zero will return
|
|
.Dv FALSE .
|
|
.Pp
|
|
.Fn vm_page_test_dirty
|
|
checks if a page has been modified via any of its physical maps,
|
|
and if so, flags the entire page as dirty.
|
|
.Fn vm_page_dirty
|
|
is called to modify the dirty bits.
|
|
.Pp
|
|
.Fn vm_page_dirty
|
|
flags the entire page as dirty.
|
|
It is expected that the page is not currently on the cache queue.
|
|
.Pp
|
|
.Fn vm_page_undirty
|
|
clears all of the dirty bits in a page.
|
|
.Sh NOTES
|
|
None of these functions are allowed to block.
|
|
.Sh AUTHORS
|
|
This manual page was written by
|
|
.An Chad David Aq Mt davidc@acns.ab.ca .
|