.\" .\" Copyright (C) 2001 Chad David . 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: src/share/man/man9/vm_page_alloc.9,v 1.6 2005/06/28 20:15:18 hmp Exp $ .\" .Dd December 19, 2010 .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 page_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, but is not inserted into the pmap. The vm_object must be locked on entry. .Pp .Fn vm_page_alloc 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 into the object at which the page should be inserted. .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_QUICK The page should only be allocated from the free queue. .It Dv VM_ALLOC_SYSTEM The page can be allocated if the cache queue is empty and the free page count is above the interrupt reserved water mark. If .Dv VM_ALLOC_INTERRUPT is set, the page can be allocated as long as the free page count is greater than zero. 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 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 Indicate a preference for a pre-zeroed page. There is no guarantee that the page thus returned will be zeroed, but it will be marked as such. .El .El .Sh RETURN VALUES The .Vt vm_page_t that was allocated is returned if successful; otherwise, .Dv NULL is returned. The returned page will be marked PG_BUSY. .Sh AUTHORS This manual page was written by .An Chad David Aq Mt davidc@acns.ab.ca .