1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * %sccs.include.redist.c% 9 * 10 * @(#)vm_pager.c 8.3 (Berkeley) 11/14/93 11 * 12 * 13 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 14 * All rights reserved. 15 * 16 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 17 * 18 * Permission to use, copy, modify and distribute this software and 19 * its documentation is hereby granted, provided that both the copyright 20 * notice and this permission notice appear in all copies of the 21 * software, derivative works or modified versions, and any portions 22 * thereof, and that both notices appear in supporting documentation. 23 * 24 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 25 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 26 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 27 * 28 * Carnegie Mellon requests users of this software to return to 29 * 30 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 31 * School of Computer Science 32 * Carnegie Mellon University 33 * Pittsburgh PA 15213-3890 34 * 35 * any improvements or extensions that they make and grant Carnegie the 36 * rights to redistribute these changes. 37 */ 38 39 /* 40 * Paging space routine stubs. Emulates a matchmaker-like interface 41 * for builtin pagers. 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/malloc.h> 47 48 #include <vm/vm.h> 49 #include <vm/vm_page.h> 50 #include <vm/vm_kern.h> 51 52 #ifdef SWAPPAGER 53 extern struct pagerops swappagerops; 54 #endif 55 56 #ifdef VNODEPAGER 57 extern struct pagerops vnodepagerops; 58 #endif 59 60 #ifdef DEVPAGER 61 extern struct pagerops devicepagerops; 62 #endif 63 64 struct pagerops *pagertab[] = { 65 #ifdef SWAPPAGER 66 &swappagerops, /* PG_SWAP */ 67 #else 68 NULL, 69 #endif 70 #ifdef VNODEPAGER 71 &vnodepagerops, /* PG_VNODE */ 72 #else 73 NULL, 74 #endif 75 #ifdef DEVPAGER 76 &devicepagerops, /* PG_DEV */ 77 #else 78 NULL, 79 #endif 80 }; 81 int npagers = sizeof (pagertab) / sizeof (pagertab[0]); 82 83 struct pagerops *dfltpagerops = NULL; /* default pager */ 84 85 /* 86 * Kernel address space for mapping pages. 87 * Used by pagers where KVAs are needed for IO. 88 */ 89 #define PAGER_MAP_SIZE (256 * PAGE_SIZE) 90 vm_map_t pager_map; 91 vm_offset_t pager_sva, pager_eva; 92 93 void 94 vm_pager_init() 95 { 96 struct pagerops **pgops; 97 98 /* 99 * Allocate a kernel submap for tracking get/put page mappings 100 */ 101 pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva, 102 PAGER_MAP_SIZE, FALSE); 103 /* 104 * Initialize known pagers 105 */ 106 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 107 if (pgops) 108 (*(*pgops)->pgo_init)(); 109 if (dfltpagerops == NULL) 110 panic("no default pager"); 111 } 112 113 /* 114 * Allocate an instance of a pager of the given type. 115 * Size, protection and offset parameters are passed in for pagers that 116 * need to perform page-level validation (e.g. the device pager). 117 */ 118 vm_pager_t 119 vm_pager_allocate(type, handle, size, prot, off) 120 int type; 121 caddr_t handle; 122 vm_size_t size; 123 vm_prot_t prot; 124 vm_offset_t off; 125 { 126 vm_pager_t pager; 127 struct pagerops *ops; 128 129 ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type]; 130 if (ops) 131 return ((*ops->pgo_alloc)(handle, size, prot, off)); 132 return (NULL); 133 } 134 135 void 136 vm_pager_deallocate(pager) 137 vm_pager_t pager; 138 { 139 if (pager == NULL) 140 panic("vm_pager_deallocate: null pager"); 141 142 VM_PAGER_DEALLOC(pager); 143 } 144 145 int 146 vm_pager_get(pager, m, sync) 147 vm_pager_t pager; 148 vm_page_t m; 149 boolean_t sync; 150 { 151 extern boolean_t vm_page_zero_fill(); 152 153 if (pager == NULL) 154 return(vm_page_zero_fill(m) ? VM_PAGER_OK : VM_PAGER_FAIL); 155 return(VM_PAGER_GET(pager, m, sync)); 156 } 157 158 int 159 vm_pager_put(pager, m, sync) 160 vm_pager_t pager; 161 vm_page_t m; 162 boolean_t sync; 163 { 164 if (pager == NULL) 165 panic("vm_pager_put: null pager"); 166 return(VM_PAGER_PUT(pager, m, sync)); 167 } 168 169 boolean_t 170 vm_pager_has_page(pager, offset) 171 vm_pager_t pager; 172 vm_offset_t offset; 173 { 174 if (pager == NULL) 175 panic("vm_pager_has_page"); 176 return(VM_PAGER_HASPAGE(pager, offset)); 177 } 178 179 /* 180 * Called by pageout daemon before going back to sleep. 181 * Gives pagers a chance to clean up any completed async pageing operations. 182 */ 183 void 184 vm_pager_sync() 185 { 186 struct pagerops **pgops; 187 188 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 189 if (pgops) 190 (*(*pgops)->pgo_putpage)(NULL, NULL, FALSE); 191 } 192 193 vm_offset_t 194 vm_pager_map_page(m) 195 vm_page_t m; 196 { 197 vm_offset_t kva; 198 199 #ifdef DEBUG 200 if ((m->flags & PG_BUSY) == 0) 201 panic("vm_pager_map_page: page not busy"); 202 if (m->flags & PG_PAGEROWNED) 203 printf("vm_pager_map_page: page %x already in pager\n", m); 204 #endif 205 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 206 #ifdef DEBUG 207 m->flags |= PG_PAGEROWNED; 208 #endif 209 pmap_enter(vm_map_pmap(pager_map), kva, VM_PAGE_TO_PHYS(m), 210 VM_PROT_DEFAULT, TRUE); 211 return(kva); 212 } 213 214 void 215 vm_pager_unmap_page(kva) 216 vm_offset_t kva; 217 { 218 #ifdef DEBUG 219 vm_page_t m; 220 221 m = PHYS_TO_VM_PAGE(pmap_extract(vm_map_pmap(pager_map), kva)); 222 #endif 223 pmap_remove(vm_map_pmap(pager_map), kva, kva + PAGE_SIZE); 224 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 225 #ifdef DEBUG 226 if (m->flags & PG_PAGEROWNED) 227 m->flags &= ~PG_PAGEROWNED; 228 else 229 printf("vm_pager_unmap_page: page %x(%x/%x) not owned\n", 230 m, kva, VM_PAGE_TO_PHYS(m)); 231 #endif 232 } 233 234 vm_pager_t 235 vm_pager_lookup(list, handle) 236 register queue_head_t *list; 237 caddr_t handle; 238 { 239 register vm_pager_t pager; 240 241 pager = (vm_pager_t) queue_first(list); 242 while (!queue_end(list, (queue_entry_t)pager)) { 243 if (pager->pg_handle == handle) 244 return(pager); 245 pager = (vm_pager_t) queue_next(&pager->pg_list); 246 } 247 return(NULL); 248 } 249 250 /* 251 * This routine gains a reference to the object. 252 * Explicit deallocation is necessary. 253 */ 254 int 255 pager_cache(object, should_cache) 256 vm_object_t object; 257 boolean_t should_cache; 258 { 259 if (object == NULL) 260 return(KERN_INVALID_ARGUMENT); 261 262 vm_object_cache_lock(); 263 vm_object_lock(object); 264 if (should_cache) 265 object->flags |= OBJ_CANPERSIST; 266 else 267 object->flags &= ~OBJ_CANPERSIST; 268 vm_object_unlock(object); 269 vm_object_cache_unlock(); 270 271 vm_object_deallocate(object); 272 273 return(KERN_SUCCESS); 274 } 275