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: src/sys/vm/phys_pager.c,v 1.3.2.3 2000/12/17 02:05:41 alfred Exp $ 26 * $DragonFly: src/sys/vm/phys_pager.c,v 1.3 2003/07/19 21:14:53 dillon Exp $ 27 */ 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 /* list of device pager objects */ 43 static struct pagerlst phys_pager_object_list; 44 45 static int phys_pager_alloc_lock, phys_pager_alloc_lock_want; 46 47 static void 48 phys_pager_init(void) 49 { 50 51 TAILQ_INIT(&phys_pager_object_list); 52 } 53 54 static vm_object_t 55 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 56 vm_ooffset_t foff) 57 { 58 vm_object_t object; 59 60 /* 61 * Offset should be page aligned. 62 */ 63 if (foff & PAGE_MASK) 64 return (NULL); 65 66 size = round_page(size); 67 68 if (handle != NULL) { 69 /* 70 * Lock to prevent object creation race condition. 71 */ 72 while (phys_pager_alloc_lock) { 73 phys_pager_alloc_lock_want++; 74 tsleep(&phys_pager_alloc_lock, 0, "ppall", 0); 75 phys_pager_alloc_lock_want--; 76 } 77 phys_pager_alloc_lock = 1; 78 79 /* 80 * Look up pager, creating as necessary. 81 */ 82 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 83 if (object == NULL) { 84 /* 85 * Allocate object and associate it with the pager. 86 */ 87 object = vm_object_allocate(OBJT_PHYS, 88 OFF_TO_IDX(foff + size)); 89 object->handle = handle; 90 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 91 pager_object_list); 92 } else { 93 /* 94 * Gain a reference to the object. 95 */ 96 vm_object_reference(object); 97 if (OFF_TO_IDX(foff + size) > object->size) 98 object->size = OFF_TO_IDX(foff + size); 99 } 100 phys_pager_alloc_lock = 0; 101 if (phys_pager_alloc_lock_want) 102 wakeup(&phys_pager_alloc_lock); 103 } else { 104 object = vm_object_allocate(OBJT_PHYS, 105 OFF_TO_IDX(foff + size)); 106 } 107 108 return (object); 109 } 110 111 static void 112 phys_pager_dealloc(vm_object_t object) 113 { 114 115 if (object->handle != NULL) 116 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 117 } 118 119 static int 120 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 121 { 122 int i, s; 123 124 s = splvm(); 125 /* 126 * Fill as many pages as vm_fault has allocated for us. 127 */ 128 for (i = 0; i < count; i++) { 129 if ((m[i]->flags & PG_ZERO) == 0) 130 vm_page_zero_fill(m[i]); 131 vm_page_flag_set(m[i], PG_ZERO); 132 /* Switch off pv_entries */ 133 vm_page_unmanage(m[i]); 134 m[i]->valid = VM_PAGE_BITS_ALL; 135 m[i]->dirty = 0; 136 /* The requested page must remain busy, the others not. */ 137 if (reqpage != i) { 138 vm_page_flag_clear(m[i], PG_BUSY); 139 m[i]->busy = 0; 140 } 141 } 142 splx(s); 143 144 return (VM_PAGER_OK); 145 } 146 147 static void 148 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 149 int *rtvals) 150 { 151 152 panic("phys_pager_putpage called"); 153 } 154 155 /* 156 * Implement a pretty aggressive clustered getpages strategy. Hint that 157 * everything in an entire 4MB window should be prefaulted at once. 158 * 159 * XXX 4MB (1024 slots per page table page) is convenient for x86, 160 * but may not be for other arches. 161 */ 162 #ifndef PHYSCLUSTER 163 #define PHYSCLUSTER 1024 164 #endif 165 static boolean_t 166 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 167 int *after) 168 { 169 vm_pindex_t base, end; 170 171 base = pindex & (~(PHYSCLUSTER - 1)); 172 end = base + (PHYSCLUSTER - 1); 173 if (before != NULL) 174 *before = pindex - base; 175 if (after != NULL) 176 *after = end - pindex; 177 return (TRUE); 178 } 179 180 struct pagerops physpagerops = { 181 phys_pager_init, 182 phys_pager_alloc, 183 phys_pager_dealloc, 184 phys_pager_getpages, 185 phys_pager_putpages, 186 phys_pager_haspage, 187 NULL 188 }; 189