phys_pager.c revision 76827
1/* 2 * Copyright (c) 2000 Peter Wemm 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD: head/sys/vm/phys_pager.c 76827 2001-05-19 01:28:09Z alfred $ 26 */ 27 28#include <sys/param.h> 29#include <sys/systm.h> 30#include <sys/linker_set.h> 31#include <sys/conf.h> 32#include <sys/kernel.h> 33#include <sys/lock.h> 34#include <sys/mutex.h> 35#include <sys/mman.h> 36#include <sys/sysctl.h> 37 38#include <vm/vm.h> 39#include <vm/vm_object.h> 40#include <vm/vm_page.h> 41#include <vm/vm_pager.h> 42#include <vm/vm_zone.h> 43 44/* prevent concurrant creation races */ 45static int phys_pager_alloc_lock; 46/* list of device pager objects */ 47static struct pagerlst phys_pager_object_list; 48/* protect access to phys_pager_object_list */ 49static struct mtx phys_pager_mtx; 50 51static void 52phys_pager_init(void) 53{ 54 55 TAILQ_INIT(&phys_pager_object_list); 56 mtx_init(&phys_pager_mtx, "phys_pager list", MTX_DEF); 57} 58 59static vm_object_t 60phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 61 vm_ooffset_t foff) 62{ 63 vm_object_t object; 64 65 /* 66 * Offset should be page aligned. 67 */ 68 if (foff & PAGE_MASK) 69 return (NULL); 70 71 size = round_page(size); 72 73 if (handle != NULL) { 74 /* 75 * Lock to prevent object creation race condition. 76 */ 77 while (phys_pager_alloc_lock) { 78 phys_pager_alloc_lock = -1; 79 msleep(&phys_pager_alloc_lock, &vm_mtx, PVM, "swpalc", 0); 80 } 81 82 /* 83 * Look up pager, creating as necessary. 84 */ 85 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 86 if (object == NULL) { 87 /* 88 * Allocate object and associate it with the pager. 89 */ 90 object = vm_object_allocate(OBJT_PHYS, 91 OFF_TO_IDX(foff + size)); 92 object->handle = handle; 93 mtx_lock(&phys_pager_mtx); 94 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 95 pager_object_list); 96 mtx_unlock(&phys_pager_mtx); 97 } else { 98 /* 99 * Gain a reference to the object. 100 */ 101 vm_object_reference(object); 102 if (OFF_TO_IDX(foff + size) > object->size) 103 object->size = OFF_TO_IDX(foff + size); 104 } 105 if (phys_pager_alloc_lock) 106 wakeup(&phys_pager_alloc_lock); 107 phys_pager_alloc_lock = 0; 108 109 } else { 110 object = vm_object_allocate(OBJT_PHYS, 111 OFF_TO_IDX(foff + size)); 112 } 113 114 return (object); 115} 116 117static void 118phys_pager_dealloc(vm_object_t object) 119{ 120 121 if (object->handle != NULL) { 122 mtx_lock(&phys_pager_mtx); 123 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 124 mtx_unlock(&phys_pager_mtx); 125 } 126} 127 128static int 129phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 130{ 131 int i, s; 132 133 s = splvm(); 134 /* 135 * Fill as many pages as vm_fault has allocated for us. 136 */ 137 for (i = 0; i < count; i++) { 138 if ((m[i]->flags & PG_ZERO) == 0) 139 vm_page_zero_fill(m[i]); 140 vm_page_flag_set(m[i], PG_ZERO); 141 /* Switch off pv_entries */ 142 vm_page_unmanage(m[i]); 143 m[i]->valid = VM_PAGE_BITS_ALL; 144 m[i]->dirty = 0; 145 /* The requested page must remain busy, the others not. */ 146 if (reqpage != i) { 147 vm_page_flag_clear(m[i], PG_BUSY); 148 m[i]->busy = 0; 149 } 150 } 151 splx(s); 152 153 return (VM_PAGER_OK); 154} 155 156static void 157phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 158 int *rtvals) 159{ 160 161 panic("phys_pager_putpage called"); 162} 163 164/* 165 * Implement a pretty aggressive clustered getpages strategy. Hint that 166 * everything in an entire 4MB window should be prefaulted at once. 167 * 168 * XXX 4MB (1024 slots per page table page) is convenient for x86, 169 * but may not be for other arches. 170 */ 171#ifndef PHYSCLUSTER 172#define PHYSCLUSTER 1024 173#endif 174static boolean_t 175phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 176 int *after) 177{ 178 vm_pindex_t base, end; 179 180 base = pindex & (~(PHYSCLUSTER - 1)); 181 end = base + (PHYSCLUSTER - 1); 182 if (before != NULL) 183 *before = pindex - base; 184 if (after != NULL) 185 *after = end - pindex; 186 return (TRUE); 187} 188 189struct pagerops physpagerops = { 190 phys_pager_init, 191 phys_pager_alloc, 192 phys_pager_dealloc, 193 phys_pager_getpages, 194 phys_pager_putpages, 195 phys_pager_haspage, 196 NULL 197}; 198