sys/uvm/uvm_object.h

   1 /*      $NetBSD: uvm_object.h,v 1.33 2012/09/14 22:20:50 rmind Exp $    */
   2
   3 /*
   4  * Copyright (c) 1997 Charles D. Cranor and Washington University.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  *
  27  * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
  28  */
  29
  30 #ifndef _UVM_UVM_OBJECT_H_
  31 #define _UVM_UVM_OBJECT_H_
  32
  33 #include <sys/queue.h>
  34 #include <sys/rbtree.h>
  35 #include <uvm/uvm_pglist.h>
  36
  37 /*
  38  * The UVM memory object interface.  Notes:
  39  *
  40  * A UVM memory object represents a list of pages, which are managed by
  41  * the object's pager operations (uvm_object::pgops).  All pages belonging
  42  * to an object are owned by it and thus protected by the object lock.
  43  *
  44  * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
  45  * By default, the lock is allocated dynamically using mutex_obj(9) cache.
  46  * Lock sharing is normally used when there is an underlying object.  For
  47  * example, vnode representing a file may have an underlying node, which
  48  * is the case for tmpfs and layered file systems.  In such case, vnode's
  49  * UVM object and the underlying UVM object shares the lock (note that the
  50  * vnode_t::v_interlock points to uvm_object::vmobjlock).
  51  *
  52  * The reference count is managed atomically for the anonymous UVM objects.
  53  * For other objects, it is arbitrary (may use the lock or atomics).
  54  */
  55
  56 struct uvm_object {
  57         kmutex_t *              vmobjlock;      /* lock on memq */
  58         const struct uvm_pagerops *pgops;       /* pager ops */
  59         struct pglist           memq;           /* pages in this object */
  60         int                     uo_npages;      /* # of pages in memq */
  61         unsigned                uo_refs;        /* reference count */
  62         struct rb_tree          rb_tree;        /* tree of pages */
  63         LIST_HEAD(,ubc_map)     uo_ubc;         /* ubc mappings */
  64 };
  65
  66 /*
  67  * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
  68  * object is a kernel memory object rather than a normal one (kernel
  69  * memory objects don't have reference counts -- they never die).
  70  *
  71  * this value is used to detected kernel object mappings at uvm_unmap()
  72  * time.   normally when an object is unmapped its pages eventaully become
  73  * deactivated and then paged out and/or freed.    this is not useful
  74  * for kernel objects... when a kernel object is unmapped we always want
  75  * to free the resources associated with the mapping.   UVM_OBJ_KERN
  76  * allows us to decide which type of unmapping we want to do.
  77  */
  78 #define UVM_OBJ_KERN            (-2)
  79
  80 #define UVM_OBJ_IS_KERN_OBJECT(uobj)                                    \
  81         ((uobj)->uo_refs == UVM_OBJ_KERN)
  82
  83 #ifdef _KERNEL
  84
  85 extern const struct uvm_pagerops uvm_vnodeops;
  86 extern const struct uvm_pagerops uvm_deviceops;
  87 extern const struct uvm_pagerops ubc_pager;
  88 extern const struct uvm_pagerops aobj_pager;
  89
  90 #define UVM_OBJ_IS_VNODE(uobj)                                          \
  91         ((uobj)->pgops == &uvm_vnodeops)
  92
  93 #define UVM_OBJ_IS_DEVICE(uobj)                                         \
  94         ((uobj)->pgops == &uvm_deviceops)
  95
  96 #define UVM_OBJ_IS_VTEXT(uobj)                                          \
  97         (UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))
  98
  99 #define UVM_OBJ_IS_CLEAN(uobj)                                          \
 100         (UVM_OBJ_IS_VNODE(uobj) && uvn_clean_p(uobj))
 101
 102 /*
 103  * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.
 104  * (ie. wants to avoid writable user mappings.)
 105  *
 106  * XXX bad name
 107  */
 108
 109 #define UVM_OBJ_NEEDS_WRITEFAULT(uobj)                                  \
 110         (UVM_OBJ_IS_VNODE(uobj) && uvn_needs_writefault_p(uobj))
 111
 112 #define UVM_OBJ_IS_AOBJ(uobj)                                           \
 113         ((uobj)->pgops == &aobj_pager)
 114
 115 extern const rb_tree_ops_t uvm_page_tree_ops;
 116
 117 #endif /* _KERNEL */
 118
 119 #endif /* _UVM_UVM_OBJECT_H_ */