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 July 24, 2001 .Dt VM_PAGE_FREE 9 .Os .Sh NAME .Nm vm_page_free , .Nm vm_page_free_toq , .Nm vm_page_free_zero , .Nm vm_page_try_to_free .Nd "free a page" .Sh SYNOPSIS n sys/param.h n vm/vm.h n vm/vm_page.h .Ft void .Fn vm_page_free "vm_page_t m" .Ft void .Fn vm_page_free_toq "vm_page_t m" .Ft void .Fn vm_page_free_zero "vm_page_t m" .Ft int .Fn vm_page_try_to_free "vm_page_t m" .Sh DESCRIPTION The .Fn vm_page_free_toq function moves a page into the free queue, and disassociates it from its object. If the page is held, wired, already free, or its busy count is not zero, the system will panic. If the .Dv PG_ZERO flag is set on the page, it is placed at the end of the free queue; otherwise, it is placed at the front.

p If the page's object is of type .Dv OBJT_VNODE and it is the last page associated with the object, the underlying vnode may be freed.

p The .Fn vm_page_free and .Fn vm_page_free_zero functions both call .Fn vm_page_free_toq to actually free the page, but .Fn vm_page_free_zero sets the .Dv PG_ZERO flag and .Fn vm_page_free clears the .Dv PG_ZERO flag prior to the call to .Fn vm_page_free_toq .

p The .Fn vm_page_try_to_free function verifies that the page is not held, wired, busy or dirty, and if so, marks the page as busy, drops any protection that may be set on the page, and frees it. .Sh RETURN VALUES .Fn vm_page_try_to_free returns 1 if it is able to free the page; otherwise, 0 is returned. .Sh SEE ALSO .Xr vm_page_busy 9 , .Xr vm_page_hold 9 , .Xr vm_page_wire 9 .Sh AUTHORS This manual page was written by .An Chad David Aq davidc@acns.ab.ca .