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 1.4 2004/10/12 19:29:34 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 #include <sys/thread2.h> 43 44 /* list of device pager objects */ 45 static struct pagerlst phys_pager_object_list; 46 47 static int phys_pager_alloc_lock, phys_pager_alloc_lock_want; 48 49 static void 50 phys_pager_init(void) 51 { 52 53 TAILQ_INIT(&phys_pager_object_list); 54 } 55 56 static vm_object_t 57 phys_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, 58 vm_ooffset_t foff) 59 { 60 vm_object_t object; 61 62 /* 63 * Offset should be page aligned. 64 */ 65 if (foff & PAGE_MASK) 66 return (NULL); 67 68 size = round_page(size); 69 70 if (handle != NULL) { 71 /* 72 * Lock to prevent object creation race condition. 73 */ 74 while (phys_pager_alloc_lock) { 75 phys_pager_alloc_lock_want++; 76 tsleep(&phys_pager_alloc_lock, 0, "ppall", 0); 77 phys_pager_alloc_lock_want--; 78 } 79 phys_pager_alloc_lock = 1; 80 81 /* 82 * Look up pager, creating as necessary. 83 */ 84 object = vm_pager_object_lookup(&phys_pager_object_list, handle); 85 if (object == NULL) { 86 /* 87 * Allocate object and associate it with the pager. 88 */ 89 object = vm_object_allocate(OBJT_PHYS, 90 OFF_TO_IDX(foff + size)); 91 object->handle = handle; 92 TAILQ_INSERT_TAIL(&phys_pager_object_list, object, 93 pager_object_list); 94 } else { 95 /* 96 * Gain a reference to the object. 97 */ 98 vm_object_reference(object); 99 if (OFF_TO_IDX(foff + size) > object->size) 100 object->size = OFF_TO_IDX(foff + size); 101 } 102 phys_pager_alloc_lock = 0; 103 if (phys_pager_alloc_lock_want) 104 wakeup(&phys_pager_alloc_lock); 105 } else { 106 object = vm_object_allocate(OBJT_PHYS, 107 OFF_TO_IDX(foff + size)); 108 } 109 110 return (object); 111 } 112 113 static void 114 phys_pager_dealloc(vm_object_t object) 115 { 116 117 if (object->handle != NULL) 118 TAILQ_REMOVE(&phys_pager_object_list, object, pager_object_list); 119 } 120 121 static int 122 phys_pager_getpages(vm_object_t object, vm_page_t *m, int count, int reqpage) 123 { 124 int i; 125 126 crit_enter(); 127 /* 128 * Fill as many pages as vm_fault has allocated for us. 129 */ 130 for (i = 0; i < count; i++) { 131 if ((m[i]->flags & PG_ZERO) == 0) 132 vm_page_zero_fill(m[i]); 133 vm_page_flag_set(m[i], PG_ZERO); 134 /* Switch off pv_entries */ 135 vm_page_unmanage(m[i]); 136 m[i]->valid = VM_PAGE_BITS_ALL; 137 m[i]->dirty = 0; 138 /* The requested page must remain busy, the others not. */ 139 if (reqpage != i) { 140 vm_page_flag_clear(m[i], PG_BUSY); 141 m[i]->busy = 0; 142 } 143 } 144 crit_exit(); 145 146 return (VM_PAGER_OK); 147 } 148 149 static void 150 phys_pager_putpages(vm_object_t object, vm_page_t *m, int count, boolean_t sync, 151 int *rtvals) 152 { 153 154 panic("phys_pager_putpage called"); 155 } 156 157 /* 158 * Implement a pretty aggressive clustered getpages strategy. Hint that 159 * everything in an entire 4MB window should be prefaulted at once. 160 * 161 * XXX 4MB (1024 slots per page table page) is convenient for x86, 162 * but may not be for other arches. 163 */ 164 #ifndef PHYSCLUSTER 165 #define PHYSCLUSTER 1024 166 #endif 167 static boolean_t 168 phys_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before, 169 int *after) 170 { 171 vm_pindex_t base, end; 172 173 base = pindex & (~(PHYSCLUSTER - 1)); 174 end = base + (PHYSCLUSTER - 1); 175 if (before != NULL) 176 *before = pindex - base; 177 if (after != NULL) 178 *after = end - pindex; 179 return (TRUE); 180 } 181 182 struct pagerops physpagerops = { 183 phys_pager_init, 184 phys_pager_alloc, 185 phys_pager_dealloc, 186 phys_pager_getpages, 187 phys_pager_putpages, 188 phys_pager_haspage, 189 NULL 190 }; 191