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 8.1 (Berkeley) 06/11/93 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) 111 int type; 112 caddr_t handle; 113 vm_size_t size; 114 vm_prot_t prot; 115 { 116 vm_pager_t pager; 117 struct pagerops *ops; 118 119 ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type]; 120 return((*ops->pgo_alloc)(handle, size, prot)); 121 } 122 123 void 124 vm_pager_deallocate(pager) 125 vm_pager_t pager; 126 { 127 if (pager == NULL) 128 panic("vm_pager_deallocate: null pager"); 129 130 VM_PAGER_DEALLOC(pager); 131 } 132 133 int 134 vm_pager_get(pager, m, sync) 135 vm_pager_t pager; 136 vm_page_t m; 137 boolean_t sync; 138 { 139 extern boolean_t vm_page_zero_fill(); 140 141 if (pager == NULL) 142 return(vm_page_zero_fill(m) ? VM_PAGER_OK : VM_PAGER_FAIL); 143 return(VM_PAGER_GET(pager, m, sync)); 144 } 145 146 int 147 vm_pager_put(pager, m, sync) 148 vm_pager_t pager; 149 vm_page_t m; 150 boolean_t sync; 151 { 152 if (pager == NULL) 153 panic("vm_pager_put: null pager"); 154 return(VM_PAGER_PUT(pager, m, sync)); 155 } 156 157 boolean_t 158 vm_pager_has_page(pager, offset) 159 vm_pager_t pager; 160 vm_offset_t offset; 161 { 162 if (pager == NULL) 163 panic("vm_pager_has_page"); 164 return(VM_PAGER_HASPAGE(pager, offset)); 165 } 166 167 /* 168 * Called by pageout daemon before going back to sleep. 169 * Gives pagers a chance to clean up any completed async pageing operations. 170 */ 171 void 172 vm_pager_sync() 173 { 174 struct pagerops **pgops; 175 176 for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) 177 (*(*pgops)->pgo_putpage)(NULL, NULL, FALSE); 178 } 179 180 vm_offset_t 181 vm_pager_map_page(m) 182 vm_page_t m; 183 { 184 vm_offset_t kva; 185 186 #ifdef DEBUG 187 if ((m->flags & PG_BUSY) == 0) 188 panic("vm_pager_map_page: page not busy"); 189 if (m->flags & PG_PAGEROWNED) 190 printf("vm_pager_map_page: page %x already in pager\n", m); 191 #endif 192 kva = kmem_alloc_wait(pager_map, PAGE_SIZE); 193 #ifdef DEBUG 194 m->flags |= PG_PAGEROWNED; 195 #endif 196 pmap_enter(vm_map_pmap(pager_map), kva, VM_PAGE_TO_PHYS(m), 197 VM_PROT_DEFAULT, TRUE); 198 return(kva); 199 } 200 201 void 202 vm_pager_unmap_page(kva) 203 vm_offset_t kva; 204 { 205 #ifdef DEBUG 206 vm_page_t m; 207 208 m = PHYS_TO_VM_PAGE(pmap_extract(vm_map_pmap(pager_map), kva)); 209 #endif 210 pmap_remove(vm_map_pmap(pager_map), kva, kva + PAGE_SIZE); 211 kmem_free_wakeup(pager_map, kva, PAGE_SIZE); 212 #ifdef DEBUG 213 if (m->flags & PG_PAGEROWNED) 214 m->flags &= ~PG_PAGEROWNED; 215 else 216 printf("vm_pager_unmap_page: page %x(%x/%x) not owned\n", 217 m, kva, VM_PAGE_TO_PHYS(m)); 218 #endif 219 } 220 221 vm_pager_t 222 vm_pager_lookup(list, handle) 223 register queue_head_t *list; 224 caddr_t handle; 225 { 226 register vm_pager_t pager; 227 228 pager = (vm_pager_t) queue_first(list); 229 while (!queue_end(list, (queue_entry_t)pager)) { 230 if (pager->pg_handle == handle) 231 return(pager); 232 pager = (vm_pager_t) queue_next(&pager->pg_list); 233 } 234 return(NULL); 235 } 236 237 /* 238 * This routine gains a reference to the object. 239 * Explicit deallocation is necessary. 240 */ 241 int 242 pager_cache(object, should_cache) 243 vm_object_t object; 244 boolean_t should_cache; 245 { 246 if (object == NULL) 247 return(KERN_INVALID_ARGUMENT); 248 249 vm_object_cache_lock(); 250 vm_object_lock(object); 251 if (should_cache) 252 object->flags |= OBJ_CANPERSIST; 253 else 254 object->flags &= ~OBJ_CANPERSIST; 255 vm_object_unlock(object); 256 vm_object_cache_unlock(); 257 258 vm_object_deallocate(object); 259 260 return(KERN_SUCCESS); 261 } 262