Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/uvm/uvm_pager.c
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1 /* $NetBSD: uvm_pager.c,v 1.62.2.1 2004/05/10 14:26:44 tron Exp $ */ 2 3 /* 4 * 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Charles D. Cranor and 19 * Washington University. 20 * 4. The name of the author may not be used to endorse or promote products 21 * derived from this software without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 33 * 34 * from: Id: uvm_pager.c,v 1.1.2.23 1998/02/02 20:38:06 chuck Exp 35 */ 36 37 /* 38 * uvm_pager.c: generic functions used to assist the pagers. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: uvm_pager.c,v 1.62.2.1 2004/05/10 14:26:44 tron Exp $"); 43 44 #include "opt_uvmhist.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/proc.h> 49 #include <sys/malloc.h> 50 #include <sys/pool.h> 51 #include <sys/vnode.h> 52 53 #define UVM_PAGER 54 #include <uvm/uvm.h> 55 56 struct pool *uvm_aiobuf_pool; 57 58 /* 59 * list of uvm pagers in the system 60 */ 61 62 struct uvm_pagerops * const uvmpagerops[] = { 63 &aobj_pager, 64 &uvm_deviceops, 65 &uvm_vnodeops, 66 &ubc_pager, 67 }; 68 69 /* 70 * the pager map: provides KVA for I/O 71 */ 72 73 struct vm_map *pager_map; /* XXX */ 74 struct simplelock pager_map_wanted_lock; 75 boolean_t pager_map_wanted; /* locked by pager map */ 76 static vaddr_t emergva; 77 static boolean_t emerginuse; 78 79 /* 80 * uvm_pager_init: init pagers (at boot time) 81 */ 82 83 void 84 uvm_pager_init() 85 { 86 u_int lcv; 87 vaddr_t sva, eva; 88 89 /* 90 * init pager map 91 */ 92 93 sva = 0; 94 pager_map = uvm_km_suballoc(kernel_map, &sva, &eva, PAGER_MAP_SIZE, 0, 95 FALSE, NULL); 96 simple_lock_init(&pager_map_wanted_lock); 97 pager_map_wanted = FALSE; 98 emergva = uvm_km_valloc(kernel_map, round_page(MAXPHYS)); 99 emerginuse = FALSE; 100 101 /* 102 * init ASYNC I/O queue 103 */ 104 105 TAILQ_INIT(&uvm.aio_done); 106 107 /* 108 * call pager init functions 109 */ 110 for (lcv = 0 ; lcv < sizeof(uvmpagerops)/sizeof(struct uvm_pagerops *); 111 lcv++) { 112 if (uvmpagerops[lcv]->pgo_init) 113 uvmpagerops[lcv]->pgo_init(); 114 } 115 } 116 117 /* 118 * uvm_pagermapin: map pages into KVA (pager_map) for I/O that needs mappings 119 * 120 * we basically just map in a blank map entry to reserve the space in the 121 * map and then use pmap_enter() to put the mappings in by hand. 122 */ 123 124 vaddr_t 125 uvm_pagermapin(pps, npages, flags) 126 struct vm_page **pps; 127 int npages; 128 int flags; 129 { 130 vsize_t size; 131 vaddr_t kva; 132 vaddr_t cva; 133 struct vm_page *pp; 134 vm_prot_t prot; 135 UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist); 136 137 UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d)", pps, npages,0,0); 138 139 /* 140 * compute protection. outgoing I/O only needs read 141 * access to the page, whereas incoming needs read/write. 142 */ 143 144 prot = VM_PROT_READ; 145 if (flags & UVMPAGER_MAPIN_READ) 146 prot |= VM_PROT_WRITE; 147 148 ReStart: 149 size = npages << PAGE_SHIFT; 150 kva = 0; /* let system choose VA */ 151 152 if (uvm_map(pager_map, &kva, size, NULL, 153 UVM_UNKNOWN_OFFSET, 0, UVM_FLAG_NOMERGE) != 0) { 154 if (curproc == uvm.pagedaemon_proc) { 155 simple_lock(&pager_map_wanted_lock); 156 if (emerginuse) { 157 UVM_UNLOCK_AND_WAIT(&emergva, 158 &pager_map_wanted_lock, FALSE, 159 "emergva", 0); 160 goto ReStart; 161 } 162 emerginuse = TRUE; 163 simple_unlock(&pager_map_wanted_lock); 164 kva = emergva; 165 /* The shift implicitly truncates to PAGE_SIZE */ 166 KASSERT(npages <= (MAXPHYS >> PAGE_SHIFT)); 167 goto enter; 168 } 169 if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { 170 UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0); 171 return(0); 172 } 173 simple_lock(&pager_map_wanted_lock); 174 pager_map_wanted = TRUE; 175 UVMHIST_LOG(maphist, " SLEEPING on pager_map",0,0,0,0); 176 UVM_UNLOCK_AND_WAIT(pager_map, &pager_map_wanted_lock, FALSE, 177 "pager_map", 0); 178 goto ReStart; 179 } 180 181 enter: 182 /* got it */ 183 for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { 184 pp = *pps++; 185 KASSERT(pp); 186 KASSERT(pp->flags & PG_BUSY); 187 pmap_kenter_pa(cva, VM_PAGE_TO_PHYS(pp), prot); 188 } 189 pmap_update(vm_map_pmap(pager_map)); 190 191 UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0); 192 return(kva); 193 } 194 195 /* 196 * uvm_pagermapout: remove pager_map mapping 197 * 198 * we remove our mappings by hand and then remove the mapping (waking 199 * up anyone wanting space). 200 */ 201 202 void 203 uvm_pagermapout(kva, npages) 204 vaddr_t kva; 205 int npages; 206 { 207 vsize_t size = npages << PAGE_SHIFT; 208 struct vm_map_entry *entries; 209 UVMHIST_FUNC("uvm_pagermapout"); UVMHIST_CALLED(maphist); 210 211 UVMHIST_LOG(maphist, " (kva=0x%x, npages=%d)", kva, npages,0,0); 212 213 /* 214 * duplicate uvm_unmap, but add in pager_map_wanted handling. 215 */ 216 217 pmap_kremove(kva, npages << PAGE_SHIFT); 218 if (kva == emergva) { 219 simple_lock(&pager_map_wanted_lock); 220 emerginuse = FALSE; 221 wakeup(&emergva); 222 simple_unlock(&pager_map_wanted_lock); 223 return; 224 } 225 226 vm_map_lock(pager_map); 227 uvm_unmap_remove(pager_map, kva, kva + size, &entries); 228 simple_lock(&pager_map_wanted_lock); 229 if (pager_map_wanted) { 230 pager_map_wanted = FALSE; 231 wakeup(pager_map); 232 } 233 simple_unlock(&pager_map_wanted_lock); 234 vm_map_unlock(pager_map); 235 if (entries) 236 uvm_unmap_detach(entries, 0); 237 pmap_update(pmap_kernel()); 238 UVMHIST_LOG(maphist,"<- done",0,0,0,0); 239 } 240 241 /* 242 * interrupt-context iodone handler for nested i/o bufs. 243 * 244 * => must be at splbio(). 245 */ 246 247 void 248 uvm_aio_biodone1(bp) 249 struct buf *bp; 250 { 251 struct buf *mbp = bp->b_private; 252 253 KASSERT(mbp != bp); 254 if (bp->b_flags & B_ERROR) { 255 mbp->b_flags |= B_ERROR; 256 mbp->b_error = bp->b_error; 257 } 258 mbp->b_resid -= bp->b_bcount; 259 pool_put(&bufpool, bp); 260 if (mbp->b_resid == 0) { 261 biodone(mbp); 262 } 263 } 264 265 /* 266 * interrupt-context iodone handler for single-buf i/os 267 * or the top-level buf of a nested-buf i/o. 268 * 269 * => must be at splbio(). 270 */ 271 272 void 273 uvm_aio_biodone(bp) 274 struct buf *bp; 275 { 276 /* reset b_iodone for when this is a single-buf i/o. */ 277 bp->b_iodone = uvm_aio_aiodone; 278 279 simple_lock(&uvm.aiodoned_lock); /* locks uvm.aio_done */ 280 TAILQ_INSERT_TAIL(&uvm.aio_done, bp, b_freelist); 281 wakeup(&uvm.aiodoned); 282 simple_unlock(&uvm.aiodoned_lock); 283 } 284 285 /* 286 * uvm_aio_aiodone: do iodone processing for async i/os. 287 * this should be called in thread context, not interrupt context. 288 */ 289 290 void 291 uvm_aio_aiodone(bp) 292 struct buf *bp; 293 { 294 int npages = bp->b_bufsize >> PAGE_SHIFT; 295 struct vm_page *pg, *pgs[npages]; 296 struct uvm_object *uobj; 297 struct simplelock *slock; 298 int s, i, error, swslot; 299 boolean_t write, swap; 300 UVMHIST_FUNC("uvm_aio_aiodone"); UVMHIST_CALLED(ubchist); 301 UVMHIST_LOG(ubchist, "bp %p", bp, 0,0,0); 302 303 error = (bp->b_flags & B_ERROR) ? (bp->b_error ? bp->b_error : EIO) : 0; 304 write = (bp->b_flags & B_READ) == 0; 305 /* XXXUBC B_NOCACHE is for swap pager, should be done differently */ 306 if (write && !(bp->b_flags & B_NOCACHE) && bioops.io_pageiodone) { 307 (*bioops.io_pageiodone)(bp); 308 } 309 310 uobj = NULL; 311 for (i = 0; i < npages; i++) { 312 pgs[i] = uvm_pageratop((vaddr_t)bp->b_data + (i << PAGE_SHIFT)); 313 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0); 314 } 315 uvm_pagermapout((vaddr_t)bp->b_data, npages); 316 317 swslot = 0; 318 slock = NULL; 319 pg = pgs[0]; 320 swap = (pg->uanon != NULL && pg->uobject == NULL) || 321 (pg->pqflags & PQ_AOBJ) != 0; 322 if (!swap) { 323 uobj = pg->uobject; 324 slock = &uobj->vmobjlock; 325 simple_lock(slock); 326 uvm_lock_pageq(); 327 } else if (error) { 328 if (pg->uobject != NULL) { 329 swslot = uao_find_swslot(pg->uobject, 330 pg->offset >> PAGE_SHIFT); 331 } else { 332 swslot = pg->uanon->an_swslot; 333 } 334 KASSERT(swslot); 335 } 336 for (i = 0; i < npages; i++) { 337 pg = pgs[i]; 338 KASSERT(swap || pg->uobject == uobj); 339 UVMHIST_LOG(ubchist, "pg %p", pg, 0,0,0); 340 341 /* 342 * for swap i/os, lock each page's object (or anon) 343 * individually since each page may need a different lock. 344 */ 345 346 if (swap) { 347 if (pg->uobject != NULL) { 348 slock = &pg->uobject->vmobjlock; 349 } else { 350 slock = &pg->uanon->an_lock; 351 } 352 simple_lock(slock); 353 uvm_lock_pageq(); 354 } 355 356 /* 357 * process errors. for reads, just mark the page to be freed. 358 * for writes, if the error was ENOMEM, we assume this was 359 * a transient failure so we mark the page dirty so that 360 * we'll try to write it again later. for all other write 361 * errors, we assume the error is permanent, thus the data 362 * in the page is lost. bummer. 363 */ 364 365 if (error) { 366 int slot; 367 if (!write) { 368 pg->flags |= PG_RELEASED; 369 continue; 370 } else if (error == ENOMEM) { 371 if (pg->flags & PG_PAGEOUT) { 372 pg->flags &= ~PG_PAGEOUT; 373 uvmexp.paging--; 374 } 375 pg->flags &= ~PG_CLEAN; 376 uvm_pageactivate(pg); 377 slot = 0; 378 } else 379 slot = SWSLOT_BAD; 380 381 if (swap) { 382 if (pg->uobject != NULL) { 383 int oldslot; 384 oldslot = uao_set_swslot(pg->uobject, 385 pg->offset >> PAGE_SHIFT, slot); 386 KASSERT(oldslot == swslot + i); 387 } else { 388 KASSERT(pg->uanon->an_swslot == 389 swslot + i); 390 pg->uanon->an_swslot = slot; 391 } 392 } 393 } 394 395 /* 396 * if the page is PG_FAKE, this must have been a read to 397 * initialize the page. clear PG_FAKE and activate the page. 398 * we must also clear the pmap "modified" flag since it may 399 * still be set from the page's previous identity. 400 */ 401 402 if (pg->flags & PG_FAKE) { 403 KASSERT(!write); 404 pg->flags &= ~PG_FAKE; 405 uvm_pageactivate(pg); 406 pmap_clear_modify(pg); 407 } 408 409 /* 410 * do accounting for pagedaemon i/o and arrange to free 411 * the pages instead of just unbusying them. 412 */ 413 414 if (pg->flags & PG_PAGEOUT) { 415 pg->flags &= ~PG_PAGEOUT; 416 uvmexp.paging--; 417 pg->flags |= PG_RELEASED; 418 } 419 420 /* 421 * for swap pages, unlock everything for this page now. 422 */ 423 424 if (swap) { 425 if (pg->uobject == NULL && pg->uanon->an_ref == 0 && 426 (pg->flags & PG_RELEASED) != 0) { 427 uvm_unlock_pageq(); 428 uvm_anon_release(pg->uanon); 429 } else { 430 uvm_page_unbusy(&pg, 1); 431 uvm_unlock_pageq(); 432 simple_unlock(slock); 433 } 434 } 435 } 436 if (!swap) { 437 uvm_page_unbusy(pgs, npages); 438 uvm_unlock_pageq(); 439 simple_unlock(slock); 440 } else { 441 KASSERT(write); 442 443 /* these pages are now only in swap. */ 444 simple_lock(&uvm.swap_data_lock); 445 KASSERT(uvmexp.swpgonly + npages <= uvmexp.swpginuse); 446 if (error != ENOMEM) 447 uvmexp.swpgonly += npages; 448 simple_unlock(&uvm.swap_data_lock); 449 if (error) { 450 if (error != ENOMEM) 451 uvm_swap_markbad(swslot, npages); 452 else 453 uvm_swap_free(swslot, npages); 454 } 455 uvmexp.pdpending--; 456 } 457 s = splbio(); 458 if (write && (bp->b_flags & B_AGE) != 0) { 459 vwakeup(bp); 460 } 461 pool_put(&bufpool, bp); 462 splx(s); 463 }
Cache object: e2b75adde68626003f275a9a01a395fd
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