sys/vm/phys_pager.c

   1 /*
   2  * (MPSAFE)
   3  *
   4  * Copyright (c) 2000 Peter Wemm
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD: src/sys/vm/phys_pager.c,v 1.3.2.3 2000/12/17 02:05:41 alfred Exp $
  28  */
  29 #include <sys/param.h>
  30 #include <sys/systm.h>
  31 #include <sys/linker_set.h>
  32 #include <sys/conf.h>
  33 #include <sys/mman.h>
  34 #include <sys/sysctl.h>
  35
  36 #include <vm/vm.h>
  37 #include <vm/vm_object.h>
  38 #include <vm/vm_page.h>
  39 #include <vm/vm_pager.h>
  40 #include <vm/vm_zone.h>
  41
  42 #include <sys/thread2.h>
  43
  44 /*
  45  * No requirements.
  46  */
  47 vm_object_t
  48 phys_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
  49 {
  50         vm_object_t object;
  51
  52         /*
  53          * Offset should be page aligned.
  54          */
  55         if (foff & PAGE_MASK)
  56                 return (NULL);
  57
  58         size = round_page64(size);
  59
  60         KKASSERT(handle == NULL);
  61         object = vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(foff + size));
  62
  63         return (object);
  64 }
  65
  66 /*
  67  * No requirements.
  68  */
  69 static void
  70 phys_pager_dealloc(vm_object_t object)
  71 {
  72         KKASSERT(object->handle == NULL);
  73         KKASSERT(object->swblock_count == 0);
  74 }
  75
  76 /*
  77  * No requirements.
  78  */
  79 static int
  80 phys_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
  81 {
  82         vm_page_t m = *mpp;
  83
  84         if ((m->flags & PG_ZERO) == 0)
  85                 vm_page_zero_fill(m);
  86         vm_page_flag_set(m, PG_ZERO);
  87         /* Switch off pv_entries */
  88         vm_page_unmanage(m);
  89         m->valid = VM_PAGE_BITS_ALL;
  90         m->dirty = VM_PAGE_BITS_ALL;
  91
  92         return (VM_PAGER_OK);
  93 }
  94
  95 /*
  96  * No requirements.
  97  */
  98 static void
  99 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count,
 100                     boolean_t sync, int *rtvals)
 101 {
 102
 103         panic("phys_pager_putpage called");
 104 }
 105
 106 /*
 107  * Implement a pretty aggressive clustered getpages strategy.  Hint that
 108  * everything in an entire 4MB window should be prefaulted at once.
 109  *
 110  * XXX 4MB (1024 slots per page table page) is convenient for x86,
 111  * but may not be for other arches.
 112  */
 113 #ifndef PHYSCLUSTER
 114 #define PHYSCLUSTER 1024
 115 #endif
 116
 117 /*
 118  * No requirements.
 119  */
 120 static boolean_t
 121 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex)
 122 {
 123         return (TRUE);
 124 }
 125
 126 struct pagerops physpagerops = {
 127         phys_pager_dealloc,
 128         phys_pager_getpage,
 129         phys_pager_putpages,
 130         phys_pager_haspage
 131 };