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 1.78 2006/09/15 15:51:13 yamt 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 1.78 2006/09/15 15:51:13 yamt Exp $"); 43 44 #include "opt_uvmhist.h" 45 #include "opt_readahead.h" 46 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/proc.h> 50 #include <sys/malloc.h> 51 #include <sys/pool.h> 52 #include <sys/vnode.h> 53 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(void) 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_alloc(kernel_map, round_page(MAXPHYS), 0, 99 UVM_KMF_VAONLY); 100 #if defined(DEBUG) 101 if (emergva == 0) 102 panic("emergva"); 103 #endif 104 emerginuse = FALSE; 105 106 /* 107 * init ASYNC I/O queue 108 */ 109 110 TAILQ_INIT(&uvm.aio_done); 111 112 /* 113 * call pager init functions 114 */ 115 for (lcv = 0 ; lcv < sizeof(uvmpagerops)/sizeof(struct uvm_pagerops *); 116 lcv++) { 117 if (uvmpagerops[lcv]->pgo_init) 118 uvmpagerops[lcv]->pgo_init(); 119 } 120 } 121 122 /* 123 * uvm_pagermapin: map pages into KVA (pager_map) for I/O that needs mappings 124 * 125 * we basically just map in a blank map entry to reserve the space in the 126 * map and then use pmap_enter() to put the mappings in by hand. 127 */ 128 129 vaddr_t 130 uvm_pagermapin(struct vm_page **pps, int npages, int flags) 131 { 132 vsize_t size; 133 vaddr_t kva; 134 vaddr_t cva; 135 struct vm_page *pp; 136 vm_prot_t prot; 137 const boolean_t pdaemon = curproc == uvm.pagedaemon_proc; 138 UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist); 139 140 UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d)", pps, npages,0,0); 141 142 /* 143 * compute protection. outgoing I/O only needs read 144 * access to the page, whereas incoming needs read/write. 145 */ 146 147 prot = VM_PROT_READ; 148 if (flags & UVMPAGER_MAPIN_READ) 149 prot |= VM_PROT_WRITE; 150 151 ReStart: 152 size = npages << PAGE_SHIFT; 153 kva = 0; /* let system choose VA */ 154 155 if (uvm_map(pager_map, &kva, size, NULL, UVM_UNKNOWN_OFFSET, 0, 156 UVM_FLAG_NOMERGE | (pdaemon ? UVM_FLAG_NOWAIT : 0)) != 0) { 157 if (pdaemon) { 158 simple_lock(&pager_map_wanted_lock); 159 if (emerginuse) { 160 UVM_UNLOCK_AND_WAIT(&emergva, 161 &pager_map_wanted_lock, FALSE, 162 "emergva", 0); 163 goto ReStart; 164 } 165 emerginuse = TRUE; 166 simple_unlock(&pager_map_wanted_lock); 167 kva = emergva; 168 /* The shift implicitly truncates to PAGE_SIZE */ 169 KASSERT(npages <= (MAXPHYS >> PAGE_SHIFT)); 170 goto enter; 171 } 172 if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { 173 UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0); 174 return(0); 175 } 176 simple_lock(&pager_map_wanted_lock); 177 pager_map_wanted = TRUE; 178 UVMHIST_LOG(maphist, " SLEEPING on pager_map",0,0,0,0); 179 UVM_UNLOCK_AND_WAIT(pager_map, &pager_map_wanted_lock, FALSE, 180 "pager_map", 0); 181 goto ReStart; 182 } 183 184 enter: 185 /* got it */ 186 for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { 187 pp = *pps++; 188 KASSERT(pp); 189 KASSERT(pp->flags & PG_BUSY); 190 pmap_kenter_pa(cva, VM_PAGE_TO_PHYS(pp), prot); 191 } 192 pmap_update(vm_map_pmap(pager_map)); 193 194 UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0); 195 return(kva); 196 } 197 198 /* 199 * uvm_pagermapout: remove pager_map mapping 200 * 201 * we remove our mappings by hand and then remove the mapping (waking 202 * up anyone wanting space). 203 */ 204 205 void 206 uvm_pagermapout(vaddr_t kva, int npages) 207 { 208 vsize_t size = npages << PAGE_SHIFT; 209 struct vm_map_entry *entries; 210 UVMHIST_FUNC("uvm_pagermapout"); UVMHIST_CALLED(maphist); 211 212 UVMHIST_LOG(maphist, " (kva=0x%x, npages=%d)", kva, npages,0,0); 213 214 /* 215 * duplicate uvm_unmap, but add in pager_map_wanted handling. 216 */ 217 218 pmap_kremove(kva, npages << PAGE_SHIFT); 219 if (kva == emergva) { 220 simple_lock(&pager_map_wanted_lock); 221 emerginuse = FALSE; 222 wakeup(&emergva); 223 simple_unlock(&pager_map_wanted_lock); 224 return; 225 } 226 227 vm_map_lock(pager_map); 228 uvm_unmap_remove(pager_map, kva, kva + size, &entries, NULL, 0); 229 simple_lock(&pager_map_wanted_lock); 230 if (pager_map_wanted) { 231 pager_map_wanted = FALSE; 232 wakeup(pager_map); 233 } 234 simple_unlock(&pager_map_wanted_lock); 235 vm_map_unlock(pager_map); 236 if (entries) 237 uvm_unmap_detach(entries, 0); 238 pmap_update(pmap_kernel()); 239 UVMHIST_LOG(maphist,"<- done",0,0,0,0); 240 } 241 242 /* 243 * interrupt-context iodone handler for nested i/o bufs. 244 * 245 * => must be at splbio(). 246 */ 247 248 void 249 uvm_aio_biodone1(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 putiobuf(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(struct buf *bp) 274 { 275 /* reset b_iodone for when this is a single-buf i/o. */ 276 bp->b_iodone = uvm_aio_aiodone; 277 278 simple_lock(&uvm.aiodoned_lock); /* locks uvm.aio_done */ 279 TAILQ_INSERT_TAIL(&uvm.aio_done, bp, b_freelist); 280 wakeup(&uvm.aiodoned); 281 simple_unlock(&uvm.aiodoned_lock); 282 } 283 284 /* 285 * uvm_aio_aiodone: do iodone processing for async i/os. 286 * this should be called in thread context, not interrupt context. 287 */ 288 289 void 290 uvm_aio_aiodone(struct buf *bp) 291 { 292 int npages = bp->b_bufsize >> PAGE_SHIFT; 293 struct vm_page *pg, *pgs[npages]; 294 struct uvm_object *uobj; 295 struct simplelock *slock; 296 int s, i, error, swslot; 297 boolean_t write, swap; 298 UVMHIST_FUNC("uvm_aio_aiodone"); UVMHIST_CALLED(ubchist); 299 UVMHIST_LOG(ubchist, "bp %p", bp, 0,0,0); 300 301 error = (bp->b_flags & B_ERROR) ? (bp->b_error ? bp->b_error : EIO) : 0; 302 write = (bp->b_flags & B_READ) == 0; 303 /* XXXUBC B_NOCACHE is for swap pager, should be done differently */ 304 if (write && !(bp->b_flags & B_NOCACHE) && bioops.io_pageiodone) { 305 (*bioops.io_pageiodone)(bp); 306 } 307 308 uobj = NULL; 309 for (i = 0; i < npages; i++) { 310 pgs[i] = uvm_pageratop((vaddr_t)bp->b_data + (i << PAGE_SHIFT)); 311 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0); 312 } 313 uvm_pagermapout((vaddr_t)bp->b_data, npages); 314 315 swslot = 0; 316 slock = NULL; 317 pg = pgs[0]; 318 swap = (pg->uanon != NULL && pg->uobject == NULL) || 319 (pg->pqflags & PQ_AOBJ) != 0; 320 if (!swap) { 321 uobj = pg->uobject; 322 slock = &uobj->vmobjlock; 323 simple_lock(slock); 324 uvm_lock_pageq(); 325 } else { 326 #if defined(VMSWAP) 327 if (error) { 328 if (pg->uobject != NULL) { 329 swslot = uao_find_swslot(pg->uobject, 330 pg->offset >> PAGE_SHIFT); 331 } else { 332 KASSERT(pg->uanon != NULL); 333 swslot = pg->uanon->an_swslot; 334 } 335 KASSERT(swslot); 336 } 337 #else /* defined(VMSWAP) */ 338 panic("%s: swap", __func__); 339 #endif /* defined(VMSWAP) */ 340 } 341 for (i = 0; i < npages; i++) { 342 pg = pgs[i]; 343 KASSERT(swap || pg->uobject == uobj); 344 UVMHIST_LOG(ubchist, "pg %p", pg, 0,0,0); 345 346 #if defined(VMSWAP) 347 /* 348 * for swap i/os, lock each page's object (or anon) 349 * individually since each page may need a different lock. 350 */ 351 352 if (swap) { 353 if (pg->uobject != NULL) { 354 slock = &pg->uobject->vmobjlock; 355 } else { 356 slock = &pg->uanon->an_lock; 357 } 358 simple_lock(slock); 359 uvm_lock_pageq(); 360 } 361 #endif /* defined(VMSWAP) */ 362 363 /* 364 * process errors. for reads, just mark the page to be freed. 365 * for writes, if the error was ENOMEM, we assume this was 366 * a transient failure so we mark the page dirty so that 367 * we'll try to write it again later. for all other write 368 * errors, we assume the error is permanent, thus the data 369 * in the page is lost. bummer. 370 */ 371 372 if (error) { 373 int slot; 374 if (!write) { 375 pg->flags |= PG_RELEASED; 376 continue; 377 } else if (error == ENOMEM) { 378 if (pg->flags & PG_PAGEOUT) { 379 pg->flags &= ~PG_PAGEOUT; 380 uvmexp.paging--; 381 } 382 pg->flags &= ~PG_CLEAN; 383 uvm_pageactivate(pg); 384 slot = 0; 385 } else 386 slot = SWSLOT_BAD; 387 388 #if defined(VMSWAP) 389 if (swap) { 390 if (pg->uobject != NULL) { 391 int oldslot; 392 oldslot = uao_set_swslot(pg->uobject, 393 pg->offset >> PAGE_SHIFT, slot); 394 KASSERT(oldslot == swslot + i); 395 } else { 396 KASSERT(pg->uanon->an_swslot == 397 swslot + i); 398 pg->uanon->an_swslot = slot; 399 } 400 } 401 #endif /* defined(VMSWAP) */ 402 } 403 404 /* 405 * if the page is PG_FAKE, this must have been a read to 406 * initialize the page. clear PG_FAKE and activate the page. 407 * we must also clear the pmap "modified" flag since it may 408 * still be set from the page's previous identity. 409 */ 410 411 if (pg->flags & PG_FAKE) { 412 KASSERT(!write); 413 pg->flags &= ~PG_FAKE; 414 #if defined(READAHEAD_STATS) 415 pg->pqflags |= PQ_READAHEAD; 416 uvm_ra_total.ev_count++; 417 #endif /* defined(READAHEAD_STATS) */ 418 KASSERT((pg->flags & PG_CLEAN) != 0); 419 uvm_pageenqueue(pg); 420 pmap_clear_modify(pg); 421 } 422 423 /* 424 * do accounting for pagedaemon i/o and arrange to free 425 * the pages instead of just unbusying them. 426 */ 427 428 if (pg->flags & PG_PAGEOUT) { 429 pg->flags &= ~PG_PAGEOUT; 430 uvmexp.paging--; 431 uvmexp.pdfreed++; 432 pg->flags |= PG_RELEASED; 433 } 434 435 #if defined(VMSWAP) 436 /* 437 * for swap pages, unlock everything for this page now. 438 */ 439 440 if (swap) { 441 if (pg->uobject == NULL && pg->uanon->an_ref == 0 && 442 (pg->flags & PG_RELEASED) != 0) { 443 uvm_unlock_pageq(); 444 uvm_anon_release(pg->uanon); 445 } else { 446 uvm_page_unbusy(&pg, 1); 447 uvm_unlock_pageq(); 448 simple_unlock(slock); 449 } 450 } 451 #endif /* defined(VMSWAP) */ 452 } 453 if (!swap) { 454 uvm_page_unbusy(pgs, npages); 455 uvm_unlock_pageq(); 456 simple_unlock(slock); 457 } else { 458 #if defined(VMSWAP) 459 KASSERT(write); 460 461 /* these pages are now only in swap. */ 462 simple_lock(&uvm.swap_data_lock); 463 KASSERT(uvmexp.swpgonly + npages <= uvmexp.swpginuse); 464 if (error != ENOMEM) 465 uvmexp.swpgonly += npages; 466 simple_unlock(&uvm.swap_data_lock); 467 if (error) { 468 if (error != ENOMEM) 469 uvm_swap_markbad(swslot, npages); 470 else 471 uvm_swap_free(swslot, npages); 472 } 473 uvmexp.pdpending--; 474 #endif /* defined(VMSWAP) */ 475 } 476 s = splbio(); 477 if (write && (bp->b_flags & B_AGE) != 0) { 478 vwakeup(bp); 479 } 480 putiobuf(bp); 481 splx(s); 482 } 483 484 /* 485 * uvm_pageratop: convert KVAs in the pager map back to their page 486 * structures. 487 */ 488 489 struct vm_page * 490 uvm_pageratop(vaddr_t kva) 491 { 492 struct vm_page *pg; 493 paddr_t pa; 494 boolean_t rv; 495 496 rv = pmap_extract(pmap_kernel(), kva, &pa); 497 KASSERT(rv); 498 pg = PHYS_TO_VM_PAGE(pa); 499 KASSERT(pg != NULL); 500 return (pg); 501 }
Cache object: 30410697ec30099a6f13a0dbb2d37c39
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