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 #include <vm/vm_page2.h>
  44
  45 /*
  46  * No requirements.
  47  */
  48 vm_object_t
  49 phys_pager_alloc(void *handle, off_t size, vm_prot_t prot, off_t foff)
  50 {
  51         vm_object_t object;
  52
  53         /*
  54          * Offset should be page aligned.
  55          */
  56         if (foff & PAGE_MASK)
  57                 return (NULL);
  58
  59         size = round_page64(size);
  60
  61         KKASSERT(handle == NULL);
  62         object = vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(foff + size));
  63
  64         return (object);
  65 }
  66
  67 /*
  68  * No requirements.
  69  */
  70 static void
  71 phys_pager_dealloc(vm_object_t object)
  72 {
  73         KKASSERT(object->handle == NULL);
  74         KKASSERT(object->swblock_count == 0);
  75 }
  76
  77 /*
  78  * No requirements.
  79  */
  80 static int
  81 phys_pager_getpage(vm_object_t object, vm_page_t *mpp, int seqaccess)
  82 {
  83         vm_page_t m = *mpp;
  84
  85         if ((m->flags & PG_ZERO) == 0)
  86                 vm_page_zero_fill(m);
  87         vm_page_flag_set(m, PG_ZERO);
  88         /* Switch off pv_entries */
  89         vm_page_unmanage(m);
  90         m->valid = VM_PAGE_BITS_ALL;
  91         m->dirty = VM_PAGE_BITS_ALL;
  92
  93         return (VM_PAGER_OK);
  94 }
  95
  96 /*
  97  * No requirements.
  98  */
  99 static void
 100 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count,
 101                     int sync, int *rtvals)
 102 {
 103
 104         panic("phys_pager_putpage called");
 105 }
 106
 107 /*
 108  * Implement a pretty aggressive clustered getpages strategy.  Hint that
 109  * everything in an entire 4MB window should be prefaulted at once.
 110  *
 111  * XXX 4MB (1024 slots per page table page) is convenient for x86,
 112  * but may not be for other arches.
 113  */
 114 #ifndef PHYSCLUSTER
 115 #define PHYSCLUSTER 1024
 116 #endif
 117
 118 /*
 119  * No requirements.
 120  */
 121 static boolean_t
 122 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex)
 123 {
 124         return (TRUE);
 125 }
 126
 127 struct pagerops physpagerops = {
 128         phys_pager_dealloc,
 129         phys_pager_getpage,
 130         phys_pager_putpages,
 131         phys_pager_haspage
 132 };