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 8.2 (Berkeley) 11/10/93 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 #endif 68 #ifdef VNODEPAGER 69 &vnodepagerops, /* PG_VNODE */ 70 #endif 71 #ifdef DEVPAGER 72 &devicepagerops, /* PG_DEV */ 73 #endif 74 }; 75 int npagers = sizeof (pagertab) / sizeof (pagertab[0]); 76 77 struct pagerops *dfltpagerops = NULL; /* default pager */ 78 79 /* 80 * Kernel address space for mapping pages. 81 * Used by pagers where KVAs are needed for IO. 82 */ 83 #define PAGER_MAP_SIZE (256 * PAGE_SIZE) 84 vm_map_t pager_map; 85 vm_offset_t pager_sva, pager_eva; 86 87 void 88 vm_pager_init() 89 { 90 struct pagerops **pgops; 91 92 /* 93 * Allocate a kernel submap for tracking get/put page mappings 94 */ 95 pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva, 96 PAGER_MAP_SIZE, FALSE); 97 /* 98 * Initialize known pagers 99 */ 100 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 101 (*(*pgops)->pgo_init)(); 102 if (dfltpagerops == NULL) 103 panic("no default pager"); 104 } 105 106 /* 107 * Allocate an instance of a pager of the given type. 108 */ 109 vm_pager_t 110 vm_pager_allocate(type, handle, size, prot, off) 111 int type; 112 caddr_t handle; 113 vm_size_t size; 114 vm_prot_t prot; 115 vm_offset_t off; 116 { 117 vm_pager_t pager; 118 struct pagerops *ops; 119 120 ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type]; 121 return ((*ops->pgo_alloc)(handle, size, prot, off)); 122 } 123 124 void 125 vm_pager_deallocate(pager) 126 vm_pager_t pager; 127 { 128 if (pager == NULL) 129 panic("vm_pager_deallocate: null pager"); 130 131 VM_PAGER_DEALLOC(pager); 132 } 133 134 int 135 vm_pager_get(pager, m, sync) 136 vm_pager_t pager; 137 vm_page_t m; 138 boolean_t sync; 139 { 140 extern boolean_t vm_page_zero_fill(); 141 142 if (pager == NULL) 143 return(vm_page_zero_fill(m) ? VM_PAGER_OK : VM_PAGER_FAIL); 144 return(VM_PAGER_GET(pager, m, sync)); 145 } 146 147 int 148 vm_pager_put(pager, m, sync) 149 vm_pager_t pager; 150 vm_page_t m; 151 boolean_t sync; 152 { 153 if (pager == NULL) 154 panic("vm_pager_put: null pager"); 155 return(VM_PAGER_PUT(pager, m, sync)); 156 } 157 158 boolean_t 159 vm_pager_has_page(pager, offset) 160 vm_pager_t pager; 161 vm_offset_t offset; 162 { 163 if (pager == NULL) 164 panic("vm_pager_has_page"); 165 return(VM_PAGER_HASPAGE(pager, offset)); 166 } 167 168 /* 169 * Called by pageout daemon before going back to sleep. 170 * Gives pagers a chance to clean up any completed async pageing operations. 171 */ 172 void 173 vm_pager_sync() 174 { 175 struct pagerops **pgops; 176 177 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 178 (*(*pgops)->pgo_putpage)(NULL, NULL, FALSE); 179 } 180 181 vm_offset_t 182 vm_pager_map_page(m) 183 vm_page_t m; 184 { 185 vm_offset_t kva; 186 187 #ifdef DEBUG 188 if ((m->flags & PG_BUSY) == 0) 189 panic("vm_pager_map_page: page not busy"); 190 if (m->flags & PG_PAGEROWNED) 191 printf("vm_pager_map_page: page %x already in pager\n", m); 192 #endif 193 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 194 #ifdef DEBUG 195 m->flags |= PG_PAGEROWNED; 196 #endif 197 pmap_enter(vm_map_pmap(pager_map), kva, VM_PAGE_TO_PHYS(m), 198 VM_PROT_DEFAULT, TRUE); 199 return(kva); 200 } 201 202 void 203 vm_pager_unmap_page(kva) 204 vm_offset_t kva; 205 { 206 #ifdef DEBUG 207 vm_page_t m; 208 209 m = PHYS_TO_VM_PAGE(pmap_extract(vm_map_pmap(pager_map), kva)); 210 #endif 211 pmap_remove(vm_map_pmap(pager_map), kva, kva + PAGE_SIZE); 212 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 213 #ifdef DEBUG 214 if (m->flags & PG_PAGEROWNED) 215 m->flags &= ~PG_PAGEROWNED; 216 else 217 printf("vm_pager_unmap_page: page %x(%x/%x) not owned\n", 218 m, kva, VM_PAGE_TO_PHYS(m)); 219 #endif 220 } 221 222 vm_pager_t 223 vm_pager_lookup(list, handle) 224 register queue_head_t *list; 225 caddr_t handle; 226 { 227 register vm_pager_t pager; 228 229 pager = (vm_pager_t) queue_first(list); 230 while (!queue_end(list, (queue_entry_t)pager)) { 231 if (pager->pg_handle == handle) 232 return(pager); 233 pager = (vm_pager_t) queue_next(&pager->pg_list); 234 } 235 return(NULL); 236 } 237 238 /* 239 * This routine gains a reference to the object. 240 * Explicit deallocation is necessary. 241 */ 242 int 243 pager_cache(object, should_cache) 244 vm_object_t object; 245 boolean_t should_cache; 246 { 247 if (object == NULL) 248 return(KERN_INVALID_ARGUMENT); 249 250 vm_object_cache_lock(); 251 vm_object_lock(object); 252 if (should_cache) 253 object->flags |= OBJ_CANPERSIST; 254 else 255 object->flags &= ~OBJ_CANPERSIST; 256 vm_object_unlock(object); 257 vm_object_cache_unlock(); 258 259 vm_object_deallocate(object); 260 261 return(KERN_SUCCESS); 262 } 263