2001-12-02 02:13:35 +00:00
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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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.\" DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 30, 2001
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.Dt VM_PAGE_DONTNEED 9
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.Os
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.Sh NAME
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.Nm vm_page_dontneed
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.Nd "indicate that a page is not needed anymore"
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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_dontneed "vm_page_t m"
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.Sh DESCRIPTION
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The
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.Fn vm_page_dontneed
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function advises the VM system that the given page is no longer
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required.
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2001-12-14 09:11:13 +00:00
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If the page is already in the inactive queue or in the cache queue, this
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2001-12-02 02:13:35 +00:00
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function does nothing; otherwise the page is deactivated.
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.Pp
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Note that
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.Fn vm_page_dontneed
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does not necessarily deactivate a page, but instead implements an
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algorithm that attempts to prevent small objects from having their
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pages reused too quickly, and large objects from flushing smaller
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ones from the queues as their pages are released.
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.Sh SEE ALSO
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.Xr vm_page_deactivate 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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