/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
* 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, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, 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 AUTHOR ``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 AUTHOR 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.
*
* from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
*/
/*
* The UVM memory object interface. Notes:
*
* A UVM memory object represents a list of pages, which are managed by
* the object's pager operations (uvm_object::pgops). All pages belonging
* to an object are owned by it and thus protected by the object lock.
*
* The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
* By default, the lock is allocated dynamically using mutex_obj(9) cache.
* Lock sharing is normally used when there is an underlying object. For
* example, vnode representing a file may have an underlying node, which
* is the case for tmpfs and layered file systems. In such case, vnode's
* UVM object and the underlying UVM object shares the lock (note that the
* vnode_t::v_interlock points to uvm_object::vmobjlock).
*
* The reference count is managed atomically for the anonymous UVM objects.
* For other objects, it is arbitrary (may use the lock or atomics).
*/
struct krwlock;
struct uvm_object {
struct krwlock * vmobjlock; /* lock on object */
const struct uvm_pagerops *pgops; /* pager ops */
int uo_npages; /* # of pages in uo_pages */
unsigned uo_refs; /* reference count */
struct radix_tree uo_pages; /* tree of pages */
LIST_HEAD(,ubc_map) uo_ubc; /* ubc mappings */
};
/*
* tags for uo_pages
*/
#define UVM_PAGE_DIRTY_TAG 1 /* might be dirty (!PG_CLEAN) */
#define UVM_PAGE_WRITEBACK_TAG 2 /* being written back */
/*
* UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
* object is a kernel memory object rather than a normal one (kernel
* memory objects don't have reference counts -- they never die).
*
* this value is used to detected kernel object mappings at uvm_unmap()
* time. normally when an object is unmapped its pages eventually become
* deactivated and then paged out and/or freed. this is not useful
* for kernel objects... when a kernel object is unmapped we always want
* to free the resources associated with the mapping. UVM_OBJ_KERN
* allows us to decide which type of unmapping we want to do.
*/
#define UVM_OBJ_KERN (-2)
