99 lines
3.0 KiB
Groff
99 lines
3.0 KiB
Groff
.\"
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.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice(s), this list of conditions and the following disclaimer as
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.\" the first lines of this file unmodified other than the possible
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.\" addition of one or more copyright notices.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice(s), this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
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.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 24, 2001
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.Dt VM_PAGE_FREE 9
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.Os
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.Sh NAME
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.Nm vm_page_free
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.Nm vm_page_free_toq
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.Nm vm_page_free_zero
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.Nm vm_page_try_to_free
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.Nd "free a page"
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.Sh SYNOPSIS
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.In sys/param.h
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.In vm/vm.h
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.In vm/vm_page.h
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.Ft void
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.Fn vm_page_free "vm_page_t m"
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.Ft void
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.Fn vm_page_free_toq "vm_page_t m"
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.Ft void
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.Fn vm_page_free_zero "vm_page_t m"
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.Ft int
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.Fn vm_page_try_to_free "vm_page_t m"
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.Sh DESCRIPTION
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The
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.Fn vm_page_free_toq
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function moves a page into the free queue, and disassociates it from
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its object.
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If the page is held, wired, already free, or its busy count is not
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zero the system will panic.
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If the
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.Dv PG_ZERO
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flag is set on the page is it placed at the end of the free queue;
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otherwise, it is placed at the front.
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.Pp
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If the page's object is of type
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.Dv OBJT_VNODE
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and it is the last page associated with the object the underlying
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vnode may be freed.
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.Pp
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The
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.Fn vm_page_free
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and
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.Fn vm_page_free_zero
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functions both call
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.Fn vm_page_free_toq
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to actually free page, but
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.Fn vm_page_free_zero
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sets the
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.Dv PG_ZERO
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flag and
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.Fn vm_page_free
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clears the
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.Dv PG_ZERO
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flag prior to the call to
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.Fn vm_page_free_toq .
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.Pp
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The
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.Fn vm_page_try_to_free
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function verifies that the page is not held, wired, busy or dirty, and
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if so marks the page as busy, drops any protection that may be set on
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the page, and frees it.
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.Sh RETURN VALUES
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.Fn vm_page_try_to_free
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returns 1 if it is able to free the page; otherwise, 0 is returned.
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.Sh SEE ALSO
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.Xr vm_page_busy 9 ,
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.Xr vm_page_hold 9 ,
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.Xr vm_page_wire 9
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.Sh AUTHORS
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This manual page was written by
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.An Chad David Aq davidc@acns.ab.ca .
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