phys_pager.c revision 60757
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 60757 2000-05-21 13:41:29Z peter $ 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/mman.h> 33#include <sys/sysctl.h> 34 35#include <vm/vm.h> 36#include <vm/vm_object.h> 37#include <vm/vm_page.h> 38#include <vm/vm_pager.h> 39#include <vm/vm_zone.h> 40 41static void phys_pager_init __P((void)); 42static vm_object_t phys_pager_alloc __P((void *, vm_ooffset_t, vm_prot_t, 43 vm_ooffset_t)); 44static void phys_pager_dealloc __P((vm_object_t)); 45static int phys_pager_getpages __P((vm_object_t, vm_page_t *, int, int)); 46static void phys_pager_putpages __P((vm_object_t, vm_page_t *, int, 47 boolean_t, int *)); 48static boolean_t phys_pager_haspage __P((vm_object_t, vm_pindex_t, int *, 49 int *)); 50 51/* list of device pager objects */ 52static struct pagerlst phys_pager_object_list; 53 54static int phys_pager_alloc_lock, phys_pager_alloc_lock_want; 55 56struct pagerops physpagerops = { 57 phys_pager_init, 58 phys_pager_alloc, 59 phys_pager_dealloc, 60 phys_pager_getpages, 61 phys_pager_putpages, 62 phys_pager_haspage, 63 NULL 64}; 65 66static void 67phys_pager_init() 68{ 69 TAILQ_INIT(&phys_pager_object_list); 70} 71 72static vm_object_t 73phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 74 vm_ooffset_t foff) 75{ 76 vm_object_t object; 77 78 /* 79 * Offset should be page aligned. 80 */ 81 if (foff & PAGE_MASK) 82 return (NULL); 83 84 size = round_page(size); 85 86 /* 87 * Lock to prevent object creation race condition. 88 */ 89 while (phys_pager_alloc_lock) { 90 phys_pager_alloc_lock_want++; 91 tsleep(&phys_pager_alloc_lock, PVM, "ppall", 0); 92 phys_pager_alloc_lock_want--; 93 } 94 phys_pager_alloc_lock = 1; 95 96 /* 97 * Look up pager, creating as necessary. 98 */ 99 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 100 if (object == NULL) { 101 /* 102 * Allocate object and associate it with the pager. 103 */ 104 object = vm_object_allocate(OBJT_PHYS, 105 OFF_TO_IDX(foff + size)); 106 object->handle = handle; 107 TAILQ_INIT(&object->un_pager.physp.physp_pglist); 108 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 109 pager_object_list); 110 } else { 111 /* 112 * Gain a reference to the object. 113 */ 114 vm_object_reference(object); 115 if (OFF_TO_IDX(foff + size) > object->size) 116 object->size = OFF_TO_IDX(foff + size); 117 } 118 119 phys_pager_alloc_lock = 0; 120 if (phys_pager_alloc_lock_want) 121 wakeup(&phys_pager_alloc_lock); 122 123 return (object); 124} 125 126static void 127phys_pager_dealloc(object) 128 vm_object_t object; 129{ 130 vm_page_t m; 131 int s; 132 133 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 134 /* 135 * Free up our fake pages. 136 */ 137 s = splvm(); 138 while ((m = TAILQ_FIRST(&object->un_pager.physp.physp_pglist)) != 0) { 139 TAILQ_REMOVE(&object->un_pager.physp.physp_pglist, m, pageq); 140 /* return the page back to normal */ 141 m->flags &= ~PG_FICTITIOUS; 142 m->dirty = 0; 143 vm_page_unwire(m, 0); 144 vm_page_flag_clear(m, PG_ZERO); 145 vm_page_free(m); 146 } 147 splx(s); 148} 149 150static int 151phys_pager_getpages(object, m, count, reqpage) 152 vm_object_t object; 153 vm_page_t *m; 154 int count; 155 int reqpage; 156{ 157 int i, s; 158 159 s = splvm(); 160 /* 161 * Fill as many pages as vm_fault has allocated for us. 162 */ 163 for (i = 0; i < count; i++) { 164 if ((m[i]->flags & PG_ZERO) == 0) 165 vm_page_zero_fill(m[i]); 166 vm_page_flag_set(m[i], PG_ZERO); 167 /* Switch off pv_entries */ 168 vm_page_wire(m[i]); 169 vm_page_flag_set(m[i], PG_FICTITIOUS); 170 m[i]->valid = VM_PAGE_BITS_ALL; 171 m[i]->dirty = 0; 172 /* The requested page must remain busy, the others not. */ 173 if (reqpage != i) { 174 vm_page_flag_clear(m[i], PG_BUSY); 175 m[i]->busy = 0; 176 } 177 TAILQ_INSERT_TAIL(&object->un_pager.physp.physp_pglist, m[i], 178 pageq); 179 } 180 splx(s); 181 182 return (VM_PAGER_OK); 183} 184 185static void 186phys_pager_putpages(object, m, count, sync, rtvals) 187 vm_object_t object; 188 vm_page_t *m; 189 int count; 190 boolean_t sync; 191 int *rtvals; 192{ 193 panic("phys_pager_putpage called"); 194} 195 196/* 197 * Implement a pretty aggressive clustered getpages strategy. Hint that 198 * everything in an entire 4MB window should be prefaulted at once. 199 * 200 * XXX 4MB (1024 slots per page table page) is convenient for x86, 201 * but may not be for other arches. 202 */ 203#ifndef PHYSCLUSTER 204#define PHYSCLUSTER 1024 205#endif 206static boolean_t 207phys_pager_haspage(object, pindex, before, after) 208 vm_object_t object; 209 vm_pindex_t pindex; 210 int *before; 211 int *after; 212{ 213 vm_pindex_t base, end; 214 215 base = pindex & (~(PHYSCLUSTER - 1)); 216 end = base + (PHYSCLUSTER - 1); 217 if (before != NULL) 218 *before = pindex - base; 219 if (after != NULL) 220 *after = end - pindex; 221 return (TRUE); 222} 223