1 /* $NetBSD: uvm_pager.c,v 1.100 2011/04/23 18:14:12 rmind Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * from: Id: uvm_pager.c,v 1.1.2.23 1998/02/02 20:38:06 chuck Exp 28 */ 29 30 /* 31 * uvm_pager.c: generic functions used to assist the pagers. 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: uvm_pager.c,v 1.100 2011/04/23 18:14:12 rmind Exp $"); 36 37 #include "opt_uvmhist.h" 38 #include "opt_readahead.h" 39 #include "opt_pagermap.h" 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/vnode.h> 44 #include <sys/buf.h> 45 46 #include <uvm/uvm.h> 47 48 /* 49 * XXX 50 * this is needed until the device strategy interface 51 * is changed to do physically-addressed i/o. 52 */ 53 54 #ifndef PAGER_MAP_DEFAULT_SIZE 55 #define PAGER_MAP_DEFAULT_SIZE (16 * 1024 * 1024) 56 #endif 57 58 #ifndef PAGER_MAP_SIZE 59 #define PAGER_MAP_SIZE PAGER_MAP_DEFAULT_SIZE 60 #endif 61 62 size_t pager_map_size = PAGER_MAP_SIZE; 63 64 /* 65 * list of uvm pagers in the system 66 */ 67 68 const struct uvm_pagerops * const uvmpagerops[] = { 69 &aobj_pager, 70 &uvm_deviceops, 71 &uvm_vnodeops, 72 &ubc_pager, 73 }; 74 75 /* 76 * the pager map: provides KVA for I/O 77 */ 78 79 struct vm_map *pager_map; /* XXX */ 80 kmutex_t pager_map_wanted_lock; 81 bool pager_map_wanted; /* locked by pager map */ 82 static vaddr_t emergva; 83 static bool emerginuse; 84 85 /* 86 * uvm_pager_init: init pagers (at boot time) 87 */ 88 89 void 90 uvm_pager_init(void) 91 { 92 u_int lcv; 93 vaddr_t sva, eva; 94 95 /* 96 * init pager map 97 */ 98 99 sva = 0; 100 pager_map = uvm_km_suballoc(kernel_map, &sva, &eva, pager_map_size, 0, 101 false, NULL); 102 mutex_init(&pager_map_wanted_lock, MUTEX_DEFAULT, IPL_NONE); 103 pager_map_wanted = false; 104 emergva = uvm_km_alloc(kernel_map, round_page(MAXPHYS), 0, 105 UVM_KMF_VAONLY); 106 #if defined(DEBUG) 107 if (emergva == 0) 108 panic("emergva"); 109 #endif 110 emerginuse = false; 111 112 /* 113 * init ASYNC I/O queue 114 */ 115 116 TAILQ_INIT(&uvm.aio_done); 117 118 /* 119 * call pager init functions 120 */ 121 for (lcv = 0 ; lcv < __arraycount(uvmpagerops); lcv++) { 122 if (uvmpagerops[lcv]->pgo_init) 123 uvmpagerops[lcv]->pgo_init(); 124 } 125 } 126 127 /* 128 * uvm_pagermapin: map pages into KVA (pager_map) for I/O that needs mappings 129 * 130 * we basically just map in a blank map entry to reserve the space in the 131 * map and then use pmap_enter() to put the mappings in by hand. 132 */ 133 134 vaddr_t 135 uvm_pagermapin(struct vm_page **pps, int npages, int flags) 136 { 137 vsize_t size; 138 vaddr_t kva; 139 vaddr_t cva; 140 struct vm_page *pp; 141 vm_prot_t prot; 142 const bool pdaemon = curlwp == uvm.pagedaemon_lwp; 143 UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist); 144 145 UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d)", pps, npages,0,0); 146 147 /* 148 * compute protection. outgoing I/O only needs read 149 * access to the page, whereas incoming needs read/write. 150 */ 151 152 prot = VM_PROT_READ; 153 if (flags & UVMPAGER_MAPIN_READ) 154 prot |= VM_PROT_WRITE; 155 156 ReStart: 157 size = npages << PAGE_SHIFT; 158 kva = 0; /* let system choose VA */ 159 160 if (uvm_map(pager_map, &kva, size, NULL, UVM_UNKNOWN_OFFSET, 0, 161 UVM_FLAG_NOMERGE | (pdaemon ? UVM_FLAG_NOWAIT : 0)) != 0) { 162 if (pdaemon) { 163 mutex_enter(&pager_map_wanted_lock); 164 if (emerginuse) { 165 UVM_UNLOCK_AND_WAIT(&emergva, 166 &pager_map_wanted_lock, false, 167 "emergva", 0); 168 goto ReStart; 169 } 170 emerginuse = true; 171 mutex_exit(&pager_map_wanted_lock); 172 kva = emergva; 173 /* The shift implicitly truncates to PAGE_SIZE */ 174 KASSERT(npages <= (MAXPHYS >> PAGE_SHIFT)); 175 goto enter; 176 } 177 if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { 178 UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0); 179 return(0); 180 } 181 mutex_enter(&pager_map_wanted_lock); 182 pager_map_wanted = true; 183 UVMHIST_LOG(maphist, " SLEEPING on pager_map",0,0,0,0); 184 UVM_UNLOCK_AND_WAIT(pager_map, &pager_map_wanted_lock, false, 185 "pager_map", 0); 186 goto ReStart; 187 } 188 189 enter: 190 /* got it */ 191 for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { 192 pp = *pps++; 193 KASSERT(pp); 194 KASSERT(pp->flags & PG_BUSY); 195 pmap_kenter_pa(cva, VM_PAGE_TO_PHYS(pp), prot, 0); 196 } 197 pmap_update(vm_map_pmap(pager_map)); 198 199 UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0); 200 return(kva); 201 } 202 203 /* 204 * uvm_pagermapout: remove pager_map mapping 205 * 206 * we remove our mappings by hand and then remove the mapping (waking 207 * up anyone wanting space). 208 */ 209 210 void 211 uvm_pagermapout(vaddr_t kva, int npages) 212 { 213 vsize_t size = npages << PAGE_SHIFT; 214 struct vm_map_entry *entries; 215 UVMHIST_FUNC("uvm_pagermapout"); UVMHIST_CALLED(maphist); 216 217 UVMHIST_LOG(maphist, " (kva=0x%x, npages=%d)", kva, npages,0,0); 218 219 /* 220 * duplicate uvm_unmap, but add in pager_map_wanted handling. 221 */ 222 223 pmap_kremove(kva, npages << PAGE_SHIFT); 224 pmap_update(pmap_kernel()); 225 226 if (kva == emergva) { 227 mutex_enter(&pager_map_wanted_lock); 228 emerginuse = false; 229 wakeup(&emergva); 230 mutex_exit(&pager_map_wanted_lock); 231 return; 232 } 233 234 vm_map_lock(pager_map); 235 uvm_unmap_remove(pager_map, kva, kva + size, &entries, NULL, 0); 236 mutex_enter(&pager_map_wanted_lock); 237 if (pager_map_wanted) { 238 pager_map_wanted = false; 239 wakeup(pager_map); 240 } 241 mutex_exit(&pager_map_wanted_lock); 242 vm_map_unlock(pager_map); 243 if (entries) 244 uvm_unmap_detach(entries, 0); 245 UVMHIST_LOG(maphist,"<- done",0,0,0,0); 246 } 247 248 /* 249 * interrupt-context iodone handler for single-buf i/os 250 * or the top-level buf of a nested-buf i/o. 251 */ 252 253 void 254 uvm_aio_biodone(struct buf *bp) 255 { 256 /* reset b_iodone for when this is a single-buf i/o. */ 257 bp->b_iodone = uvm_aio_aiodone; 258 259 workqueue_enqueue(uvm.aiodone_queue, &bp->b_work, NULL); 260 } 261 262 void 263 uvm_aio_aiodone_pages(struct vm_page **pgs, int npages, bool write, int error) 264 { 265 struct uvm_object *uobj; 266 struct vm_page *pg; 267 kmutex_t *slock; 268 int pageout_done; 269 int swslot; 270 int i; 271 bool swap; 272 UVMHIST_FUNC("uvm_aio_aiodone_pages"); UVMHIST_CALLED(ubchist); 273 274 swslot = 0; 275 pageout_done = 0; 276 slock = NULL; 277 uobj = NULL; 278 pg = pgs[0]; 279 swap = (pg->uanon != NULL && pg->uobject == NULL) || 280 (pg->pqflags & PQ_AOBJ) != 0; 281 if (!swap) { 282 uobj = pg->uobject; 283 slock = &uobj->vmobjlock; 284 mutex_enter(slock); 285 mutex_enter(&uvm_pageqlock); 286 } else { 287 #if defined(VMSWAP) 288 if (error) { 289 if (pg->uobject != NULL) { 290 swslot = uao_find_swslot(pg->uobject, 291 pg->offset >> PAGE_SHIFT); 292 } else { 293 KASSERT(pg->uanon != NULL); 294 swslot = pg->uanon->an_swslot; 295 } 296 KASSERT(swslot); 297 } 298 #else /* defined(VMSWAP) */ 299 panic("%s: swap", __func__); 300 #endif /* defined(VMSWAP) */ 301 } 302 for (i = 0; i < npages; i++) { 303 pg = pgs[i]; 304 KASSERT(swap || pg->uobject == uobj); 305 UVMHIST_LOG(ubchist, "pg %p", pg, 0,0,0); 306 307 #if defined(VMSWAP) 308 /* 309 * for swap i/os, lock each page's object (or anon) 310 * individually since each page may need a different lock. 311 */ 312 313 if (swap) { 314 if (pg->uobject != NULL) { 315 slock = &pg->uobject->vmobjlock; 316 } else { 317 slock = &pg->uanon->an_lock; 318 } 319 mutex_enter(slock); 320 mutex_enter(&uvm_pageqlock); 321 } 322 #endif /* defined(VMSWAP) */ 323 324 /* 325 * process errors. for reads, just mark the page to be freed. 326 * for writes, if the error was ENOMEM, we assume this was 327 * a transient failure so we mark the page dirty so that 328 * we'll try to write it again later. for all other write 329 * errors, we assume the error is permanent, thus the data 330 * in the page is lost. bummer. 331 */ 332 333 if (error) { 334 int slot; 335 if (!write) { 336 pg->flags |= PG_RELEASED; 337 continue; 338 } else if (error == ENOMEM) { 339 if (pg->flags & PG_PAGEOUT) { 340 pg->flags &= ~PG_PAGEOUT; 341 pageout_done++; 342 } 343 pg->flags &= ~PG_CLEAN; 344 uvm_pageactivate(pg); 345 slot = 0; 346 } else 347 slot = SWSLOT_BAD; 348 349 #if defined(VMSWAP) 350 if (swap) { 351 if (pg->uobject != NULL) { 352 int oldslot; 353 oldslot = uao_set_swslot(pg->uobject, 354 pg->offset >> PAGE_SHIFT, slot); 355 KASSERT(oldslot == swslot + i); 356 } else { 357 KASSERT(pg->uanon->an_swslot == 358 swslot + i); 359 pg->uanon->an_swslot = slot; 360 } 361 } 362 #endif /* defined(VMSWAP) */ 363 } 364 365 /* 366 * if the page is PG_FAKE, this must have been a read to 367 * initialize the page. clear PG_FAKE and activate the page. 368 * we must also clear the pmap "modified" flag since it may 369 * still be set from the page's previous identity. 370 */ 371 372 if (pg->flags & PG_FAKE) { 373 KASSERT(!write); 374 pg->flags &= ~PG_FAKE; 375 #if defined(READAHEAD_STATS) 376 pg->pqflags |= PQ_READAHEAD; 377 uvm_ra_total.ev_count++; 378 #endif /* defined(READAHEAD_STATS) */ 379 KASSERT((pg->flags & PG_CLEAN) != 0); 380 uvm_pageenqueue(pg); 381 pmap_clear_modify(pg); 382 } 383 384 /* 385 * do accounting for pagedaemon i/o and arrange to free 386 * the pages instead of just unbusying them. 387 */ 388 389 if (pg->flags & PG_PAGEOUT) { 390 pg->flags &= ~PG_PAGEOUT; 391 pageout_done++; 392 uvmexp.pdfreed++; 393 pg->flags |= PG_RELEASED; 394 } 395 396 #if defined(VMSWAP) 397 /* 398 * for swap pages, unlock everything for this page now. 399 */ 400 401 if (swap) { 402 if (pg->uobject == NULL && pg->uanon->an_ref == 0 && 403 (pg->flags & PG_RELEASED) != 0) { 404 mutex_exit(&uvm_pageqlock); 405 uvm_anon_release(pg->uanon); 406 } else { 407 uvm_page_unbusy(&pg, 1); 408 mutex_exit(&uvm_pageqlock); 409 mutex_exit(slock); 410 } 411 } 412 #endif /* defined(VMSWAP) */ 413 } 414 uvm_pageout_done(pageout_done); 415 if (!swap) { 416 uvm_page_unbusy(pgs, npages); 417 mutex_exit(&uvm_pageqlock); 418 mutex_exit(slock); 419 } else { 420 #if defined(VMSWAP) 421 KASSERT(write); 422 423 /* these pages are now only in swap. */ 424 mutex_enter(&uvm_swap_data_lock); 425 KASSERT(uvmexp.swpgonly + npages <= uvmexp.swpginuse); 426 if (error != ENOMEM) 427 uvmexp.swpgonly += npages; 428 mutex_exit(&uvm_swap_data_lock); 429 if (error) { 430 if (error != ENOMEM) 431 uvm_swap_markbad(swslot, npages); 432 else 433 uvm_swap_free(swslot, npages); 434 } 435 uvmexp.pdpending--; 436 #endif /* defined(VMSWAP) */ 437 } 438 } 439 440 /* 441 * uvm_aio_aiodone: do iodone processing for async i/os. 442 * this should be called in thread context, not interrupt context. 443 */ 444 445 void 446 uvm_aio_aiodone(struct buf *bp) 447 { 448 int npages = bp->b_bufsize >> PAGE_SHIFT; 449 struct vm_page *pgs[npages]; 450 int i, error; 451 bool write; 452 UVMHIST_FUNC("uvm_aio_aiodone"); UVMHIST_CALLED(ubchist); 453 UVMHIST_LOG(ubchist, "bp %p", bp, 0,0,0); 454 455 error = bp->b_error; 456 write = (bp->b_flags & B_READ) == 0; 457 458 for (i = 0; i < npages; i++) { 459 pgs[i] = uvm_pageratop((vaddr_t)bp->b_data + (i << PAGE_SHIFT)); 460 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0); 461 } 462 uvm_pagermapout((vaddr_t)bp->b_data, npages); 463 464 uvm_aio_aiodone_pages(pgs, npages, write, error); 465 466 if (write && (bp->b_cflags & BC_AGE) != 0) { 467 mutex_enter(bp->b_objlock); 468 vwakeup(bp); 469 mutex_exit(bp->b_objlock); 470 } 471 putiobuf(bp); 472 } 473 474 /* 475 * uvm_pageratop: convert KVAs in the pager map back to their page 476 * structures. 477 */ 478 479 struct vm_page * 480 uvm_pageratop(vaddr_t kva) 481 { 482 struct vm_page *pg; 483 paddr_t pa; 484 bool rv; 485 486 rv = pmap_extract(pmap_kernel(), kva, &pa); 487 KASSERT(rv); 488 pg = PHYS_TO_VM_PAGE(pa); 489 KASSERT(pg != NULL); 490 return (pg); 491 } 492