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.\" |
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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: src/share/man/man9/vm_page_free.9,v 1.2 2001/08/08 10:04:08 ru Exp $ |
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.\" $MidnightBSD$ |
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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, it is 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 the 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 . |
