1.\" 2.\" Copyright (C) 2001 Chad David <davidc@acns.ab.ca>. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice(s), this list of conditions and the following disclaimer as 9.\" the first lines of this file unmodified other than the possible 10.\" addition of one or more copyright notices. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice(s), this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY 16.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18.\" DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY 19.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 22.\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH 25.\" DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd July 24, 2001 30.Dt VM_PAGE_FREE 9 31.Os 32.Sh NAME 33.Nm vm_page_free , 34.Nm vm_page_free_toq , 35.Nm vm_page_free_zero , 36.Nm vm_page_try_to_free 37.Nd "free a page" 38.Sh SYNOPSIS 39.In sys/param.h 40.In vm/vm.h 41.In vm/vm_page.h 42.Ft void 43.Fn vm_page_free "vm_page_t m" 44.Ft void 45.Fn vm_page_free_toq "vm_page_t m" 46.Ft void 47.Fn vm_page_free_zero "vm_page_t m" 48.Ft int 49.Fn vm_page_try_to_free "vm_page_t m" 50.Sh DESCRIPTION 51The 52.Fn vm_page_free_toq 53function moves a page into the free queue, and disassociates it from 54its object. 55If the page is held, wired, already free, or its busy count is not 56zero, the system will panic. 57If the 58.Dv PG_ZERO 59flag is set on the page, it is placed at the end of the free queue; 60otherwise, it is placed at the front. 61.Pp 62If the page's object is of type 63.Dv OBJT_VNODE 64and it is the last page associated with the object, the underlying 65vnode may be freed. 66.Pp 67The 68.Fn vm_page_free 69and 70.Fn vm_page_free_zero 71functions both call 72.Fn vm_page_free_toq 73to actually free the page, but 74.Fn vm_page_free_zero 75sets the 76.Dv PG_ZERO 77flag and 78.Fn vm_page_free 79clears the 80.Dv PG_ZERO 81flag prior to the call to 82.Fn vm_page_free_toq . 83.Pp 84The 85.Fn vm_page_try_to_free 86function verifies that the page is not held, wired, busy or dirty, and 87if so, marks the page as busy, drops any protection that may be set on 88the page, and frees it. 89.Sh RETURN VALUES 90.Fn vm_page_try_to_free 91returns 1 if it is able to free the page; otherwise, 0 is returned. 92.Sh SEE ALSO 93.Xr vm_page_busy 9 , 94.Xr vm_page_hold 9 , 95.Xr vm_page_wire 9 96.Sh AUTHORS 97This manual page was written by 98.An Chad David Aq Mt davidc@acns.ab.ca . 99