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 severe low-free-pages threshold
  55  *
  56  * This causes user processes to stall to avoid exhausting memory that
  57  * the kernel might need.
  58  *
  59  * reserved < severe < minimum < target < paging_target
  60  */
  61 static __inline
  62 int
  63 vm_page_count_severe(void)
  64 {
  65     return (vmstats.v_free_severe >
  66             vmstats.v_free_count + vmstats.v_cache_count ||
  67             vmstats.v_free_reserved > vmstats.v_free_count);
  68 }
  69
  70 /*
  71  * Return TRUE if we are under our minimum low-free-pages threshold.
  72  * This activates the pageout demon.  The pageout demon tries to
  73  * reach the target but may stop once it satisfies the minimum.
  74  *
  75  * reserved < severe < minimum < target < paging_target
  76  */
  77 static __inline
  78 int
  79 vm_page_count_min(int donotcount)
  80 {
  81     return (vmstats.v_free_min + donotcount >
  82             (vmstats.v_free_count + vmstats.v_cache_count) ||
  83             vmstats.v_free_reserved > vmstats.v_free_count);
  84 }
  85
  86 /*
  87  * Return TRUE if we are under our free page target.  The pageout demon
  88  * tries to reach the target but may stop once it gets past the min.
  89  */
  90 static __inline
  91 int
  92 vm_page_count_target(void)
  93 {
  94     return (vmstats.v_free_target >
  95             (vmstats.v_free_count + vmstats.v_cache_count) ||
  96             vmstats.v_free_reserved > vmstats.v_free_count);
  97 }
  98
  99 /*
 100  * Return the number of pages the pageout daemon needs to move into the
 101  * cache or free lists.  A negative number means we have sufficient free
 102  * pages.
 103  *
 104  * The target free+cache is greater than vm_page_count_target().  The
 105  * frontend uses vm_page_count_target() while the backend continue freeing
 106  * based on vm_paging_target().
 107  *
 108  * This function DOES NOT return TRUE or FALSE.
 109  */
 110 static __inline
 111 int
 112 vm_paging_target(void)
 113 {
 114     return (
 115         (vmstats.v_free_target + vmstats.v_cache_min) -
 116         (vmstats.v_free_count + vmstats.v_cache_count)
 117     );
 118 }
 119
 120 /*
 121  * Return TRUE if hysteresis dictates we should nominally wakeup the
 122  * pageout daemon to start working on freeing up some memory.  This
 123  * routine should NOT be used to determine when to block on the VM system.
 124  * We want to wakeup the pageout daemon before we might otherwise block.
 125  *
 126  * Paging begins when cache+free drops below cache_min + free_min.
 127  */
 128 static __inline
 129 int
 130 vm_paging_needed(void)
 131 {
 132     if (vmstats.v_free_min + vmstats.v_cache_min >
 133         vmstats.v_free_count + vmstats.v_cache_count) {
 134                 return 1;
 135     }
 136     if (vmstats.v_free_min > vmstats.v_free_count)
 137                 return 1;
 138     return 0;
 139 }
 140
 141 static __inline
 142 void
 143 vm_page_event(vm_page_t m, vm_page_event_t event)
 144 {
 145     if (m->flags & PG_ACTIONLIST)
 146         vm_page_event_internal(m, event);
 147 }
 148
 149 static __inline
 150 void
 151 vm_page_init_action(vm_page_t m, vm_page_action_t action,
 152                     void (*func)(vm_page_t, vm_page_action_t), void *data)
 153 {
 154     action->m = m;
 155     action->func = func;
 156     action->data = data;
 157 }
 158
 159 /*
 160  * Clear dirty bits in the VM page but truncate the
 161  * end to a DEV_BSIZE'd boundary.
 162  *
 163  * Used when reading data in, typically via getpages.
 164  * The partial device block at the end of the truncation
 165  * range should not lose its dirty bit.
 166  *
 167  * NOTE: This function does not clear the pmap modified bit.
 168  */
 169 static __inline
 170 void
 171 vm_page_clear_dirty_end_nonincl(vm_page_t m, int base, int size)
 172 {
 173     size = (base + size) & ~DEV_BMASK;
 174     if (base < size)
 175         vm_page_clear_dirty(m, base, size - base);
 176 }
 177
 178 /*
 179  * Clear dirty bits in the VM page but truncate the
 180  * beginning to a DEV_BSIZE'd boundary.
 181  *
 182  * Used when truncating a buffer.  The partial device
 183  * block at the beginning of the truncation range
 184  * should not lose its dirty bit.
 185  *
 186  * NOTE: This function does not clear the pmap modified bit.
 187  */
 188 static __inline
 189 void
 190 vm_page_clear_dirty_beg_nonincl(vm_page_t m, int base, int size)
 191 {
 192     size += base;
 193     base = (base + DEV_BMASK) & ~DEV_BMASK;
 194     if (base < size)
 195         vm_page_clear_dirty(m, base, size - base);
 196 }
 197
 198 #endif  /* _KERNEL */
 199 #endif  /* _VM_VM_PAGE2_H_ */
 200