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diff --git a/share/man/man9/vm_page_alloc.9 b/share/man/man9/vm_page_alloc.9 new file mode 100644 index 0000000..082574f --- /dev/null +++ b/share/man/man9/vm_page_alloc.9 @@ -0,0 +1,139 @@ +.\" +.\" 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 January 28, 2012 +.Dt VM_PAGE_ALLOC 9 +.Os +.Sh NAME +.Nm vm_page_alloc +.Nd "allocate a page for a" +.Vt vm_object +.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 req" +.Sh DESCRIPTION +The +.Fn vm_page_alloc +function allocates a page at +.Fa pindex +within +.Fa object . +It is assumed that a page has not already been allocated at +.Fa pindex . +The page returned is inserted into the object, unless +.Dv VM_ALLOC_NOOBJ +is specified in the +.Fa req . +The page may exist in the vm object cache, in which case it will +be reactivated instead, moving from the cache into the object page list. +.Pp +.Fn vm_page_alloc +will not sleep. +.Pp +Its arguments are: +.Bl -tag -width ".Fa object" +.It Fa object +The VM object to allocate the page for. +The +.Fa object +must be locked if +.Dv VM_ALLOC_NOOBJ +is not specified. +.It Fa pindex +The index into the object at which the page should be inserted. +.It Fa req +The bitwise-inclusive OR of a class and any optional flags indicating +how the page should be allocated. +.Pp +Exactly one of the following classes must be specified: +.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 if the cache is empty and the free +page count is above the interrupt reserved water mark. +This flag 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. +A page will be returned successfully if the free page count is greater +than zero. +.El +.Pp +The optional flags are: +.Bl -tag -width ".Dv VM_ALLOC_IFNOTCACHED" +.It Dv VM_ALLOC_NOBUSY +The returned page will not be exclusive busy. +.It Dv VM_ALLOC_NODUMP +The returned page will not be included in any kernel core dumps +regardless of whether or not it is mapped in to KVA. +.It Dv VM_ALLOC_NOOBJ +Do not associate the allocated page with a vm object. +The +.Fa object +argument is ignored. +.It Dv VM_ALLOC_IFCACHED +Allocate the page only if it is cached. +Otherwise, return +.Dv NULL . +.It Dv VM_ALLOC_IFNOTCACHED +Only allocate the page if it is not cached in the +.Fa object . +If the page at the specified +.Fa pindex +is cached, NULL is returned instead. +.It Dv VM_ALLOC_SBUSY +The returned page will be shared busy. +.It Dv VM_ALLOC_WIRED +The returned page will be wired. +.It Dv VM_ALLOC_ZERO +Indicate a preference for a pre-zeroed page. +There is no guarantee that the returned page will be zeroed, but it +will have the +.Dv PG_ZERO +flag set if it is zeroed. +.El +.El +.Sh RETURN VALUES +The +.Vt vm_page_t +that was allocated 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 manual page was written by +.An Chad David Aq Mt davidc@acns.ab.ca . |
