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+.\"
+.\" 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 13, 2001
+.Dt VM_PAGE_ALLOC 9
+.Os
+.Sh NAME
+.Nm vm_page_alloc
+.Nd "allocates a page for the object and index"
+.Sh SYNOPSIS
+.In sys/param.h
+.In vm/vm.h
+.In vm/vm_page.h
+.Ft vm_page_t
+.Fn vm_page_alloc "vm_object_t object" "vm_pindex_t pindex" "int page_req"
+.Sh DESCRIPTION
+The
+.Fn vm_page_alloc
+function allocates a page for
+.Fa pindex
+in the VM object
+.Fa object .
+It is assumed that a page has not already been allocated for
+.Fa pindex
+and
+.Fa object .
+.Pp
+The
+.Fn vm_page_alloc
+function will not block.
+.Pp
+Its arguments are:
+.Bl -tag -width ".Fa page_req"
+.It Fa object
+The VM object to allocate the page for.
+.It Fa pindex
+The index of the page that should be allocated.
+.It Fa page_req
+A flag indicating how the page should be allocated.
+.Bl -tag -width ".Dv VM_ALLOC_INTERRUPT"
+.It Dv VM_ALLOC_NORMAL
+The page should be allocated with no special treatment.
+.It Dv VM_ALLOC_SYSTEM
+The page can be allocated even if the buffer cache queue is empty
+and the free count is above the interrupt reserved water mark.
+This should be used only when the system really needs the page.
+.It Dv VM_ALLOC_INTERRUPT
+.Fn vm_page_alloc
+is being called during an interrupt and therefore the cache cannot
+be accessed.
+The page will only be returned successfully if the free count is greater
+than zero.
+.It Dv VM_ALLOC_ZERO
+The same as
+.Dv VM_ALLOC_NORMAL
+except the page returned is zeroed.
+.El
+.El
+.Sh RETURN VALUES
+A
+.Vt vm_page_t
+is returned if successful; otherwise,
+.Dv NULL
+is returned.
+.Sh NOTES
+The pager process is always upgraded to
+.Dv VM_ALLOC_SYSTEM
+unless
+.Dv VM_ALLOC_INTERRUPT
+is set.
+.Sh AUTHORS
+This man page was written by
+.An Chad David Aq davidc@acns.ab.ca .
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