sys/vm/vm_page2.h

   1 /*-
   2  * Copyright (c) 1982, 1986, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)vmmeter.h   8.2 (Berkeley) 7/10/94
  34  * $FreeBSD: src/sys/sys/vmmeter.h,v 1.21.2.2 2002/10/10 19:28:21 dillon Exp $
  35  * $DragonFly: src/sys/vm/vm_page2.h,v 1.3 2008/04/14 20:00:29 dillon Exp $
  36  */
  37
  38 #ifndef _VM_VM_PAGE2_H_
  39 #define _VM_VM_PAGE2_H_
  40
  41 #ifndef _SYS_VMMETER_H_
  42 #include <sys/vmmeter.h>
  43 #endif
  44 #ifndef _SYS_QUEUE_H_
  45 #include <sys/queue.h>
  46 #endif
  47 #ifndef _VM_PAGE_H_
  48 #include <vm/vm_page.h>
  49 #endif
  50
  51 #ifdef _KERNEL
  52
  53 /*
  54  * Return TRUE if we are under our reserved low-free-pages threshold
  55  */
  56
  57 static __inline
  58 int
  59 vm_page_count_reserved(void)
  60 {
  61     return (vmstats.v_free_reserved >
  62         (vmstats.v_free_count + vmstats.v_cache_count));
  63 }
  64
  65 /*
  66  * Return TRUE if we are under our severe low-free-pages threshold
  67  *
  68  * This routine is typically used at the user<->system interface to determine
  69  * whether we need to block in order to avoid a low memory deadlock.
  70  */
  71
  72 static __inline
  73 int
  74 vm_page_count_severe(void)
  75 {
  76     return (vmstats.v_free_severe >
  77         (vmstats.v_free_count + vmstats.v_cache_count));
  78 }
  79
  80 /*
  81  * Return TRUE if we are under our minimum low-free-pages threshold.
  82  *
  83  * This routine is typically used within the system to determine whether
  84  * we can execute potentially very expensive code in terms of memory.  It
  85  * is also used by the pageout daemon to calculate when to sleep, when
  86  * to wake waiters up, and when (after making a pass) to become more
  87  * desparate.
  88  */
  89
  90 static __inline
  91 int
  92 vm_page_count_min(void)
  93 {
  94     return (vmstats.v_free_min >
  95         (vmstats.v_free_count + vmstats.v_cache_count));
  96 }
  97
  98 /*
  99  * Return TRUE if we have not reached our free page target during
 100  * free page recovery operations.
 101  */
 102
 103 static __inline
 104 int
 105 vm_page_count_target(void)
 106 {
 107     return (vmstats.v_free_target >
 108         (vmstats.v_free_count + vmstats.v_cache_count));
 109 }
 110
 111 /*
 112  * Return the number of pages we need to free-up or cache
 113  * A positive number indicates that we do not have enough free pages.
 114  */
 115
 116 static __inline
 117 int
 118 vm_paging_target(void)
 119 {
 120     return (
 121         (vmstats.v_free_target + vmstats.v_cache_min) -
 122         (vmstats.v_free_count + vmstats.v_cache_count)
 123     );
 124 }
 125
 126 /*
 127  * Return a positive number if the pagedaemon needs to be woken up.
 128  */
 129
 130 static __inline
 131 int
 132 vm_paging_needed(void)
 133 {
 134     return (
 135         (vmstats.v_free_reserved + vmstats.v_cache_min) >
 136         (vmstats.v_free_count + vmstats.v_cache_count)
 137     );
 138 }
 139
 140 static __inline
 141 void
 142 vm_page_event(vm_page_t m, vm_page_event_t event)
 143 {
 144     if (LIST_FIRST(&m->action_list))
 145         vm_page_event_internal(m, event);
 146 }
 147
 148 static __inline
 149 void
 150 vm_page_init_action(vm_page_action_t action,
 151                     void (*func)(vm_page_t, vm_page_action_t), void *data)
 152 {
 153     action->func = func;
 154     action->data = data;
 155 }
 156
 157 static __inline
 158 void
 159 vm_page_register_action(vm_page_t m, vm_page_action_t action,
 160                         vm_page_event_t event)
 161 {
 162     action->event = event;
 163     LIST_INSERT_HEAD(&m->action_list, action, entry);
 164 }
 165
 166 static __inline
 167 void
 168 vm_page_unregister_action(vm_page_t m, vm_page_action_t action)
 169 {
 170     if (action->event != VMEVENT_NONE) {
 171         action->event = VMEVENT_NONE;
 172         LIST_REMOVE(action, entry);
 173     }
 174 }
 175
 176 #endif  /* _KERNEL */
 177 #endif  /* _VM_VM_PAGE2_H_ */
 178