1 /* $NetBSD: uvm_pager.c,v 1.66 2005/04/01 11:59:39 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 1.66 2005/04/01 11:59:39 yamt 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_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(pps, npages, flags) 131 struct vm_page **pps; 132 int npages; 133 int flags; 134 { 135 vsize_t size; 136 vaddr_t kva; 137 vaddr_t cva; 138 struct vm_page *pp; 139 vm_prot_t prot; 140 UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist); 141 142 UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d)", pps, npages,0,0); 143 144 /* 145 * compute protection. outgoing I/O only needs read 146 * access to the page, whereas incoming needs read/write. 147 */ 148 149 prot = VM_PROT_READ; 150 if (flags & UVMPAGER_MAPIN_READ) 151 prot |= VM_PROT_WRITE; 152 153 ReStart: 154 size = npages << PAGE_SHIFT; 155 kva = 0; /* let system choose VA */ 156 157 if (uvm_map(pager_map, &kva, size, NULL, 158 UVM_UNKNOWN_OFFSET, 0, UVM_FLAG_NOMERGE) != 0) { 159 if (curproc == uvm.pagedaemon_proc) { 160 simple_lock(&pager_map_wanted_lock); 161 if (emerginuse) { 162 UVM_UNLOCK_AND_WAIT(&emergva, 163 &pager_map_wanted_lock, FALSE, 164 "emergva", 0); 165 goto ReStart; 166 } 167 emerginuse = TRUE; 168 simple_unlock(&pager_map_wanted_lock); 169 kva = emergva; 170 /* The shift implicitly truncates to PAGE_SIZE */ 171 KASSERT(npages <= (MAXPHYS >> PAGE_SHIFT)); 172 goto enter; 173 } 174 if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { 175 UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0); 176 return(0); 177 } 178 simple_lock(&pager_map_wanted_lock); 179 pager_map_wanted = TRUE; 180 UVMHIST_LOG(maphist, " SLEEPING on pager_map",0,0,0,0); 181 UVM_UNLOCK_AND_WAIT(pager_map, &pager_map_wanted_lock, FALSE, 182 "pager_map", 0); 183 goto ReStart; 184 } 185 186 enter: 187 /* got it */ 188 for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { 189 pp = *pps++; 190 KASSERT(pp); 191 KASSERT(pp->flags & PG_BUSY); 192 pmap_kenter_pa(cva, VM_PAGE_TO_PHYS(pp), prot); 193 } 194 pmap_update(vm_map_pmap(pager_map)); 195 196 UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0); 197 return(kva); 198 } 199 200 /* 201 * uvm_pagermapout: remove pager_map mapping 202 * 203 * we remove our mappings by hand and then remove the mapping (waking 204 * up anyone wanting space). 205 */ 206 207 void 208 uvm_pagermapout(kva, npages) 209 vaddr_t kva; 210 int npages; 211 { 212 vsize_t size = npages << PAGE_SHIFT; 213 struct vm_map_entry *entries; 214 UVMHIST_FUNC("uvm_pagermapout"); UVMHIST_CALLED(maphist); 215 216 UVMHIST_LOG(maphist, " (kva=0x%x, npages=%d)", kva, npages,0,0); 217 218 /* 219 * duplicate uvm_unmap, but add in pager_map_wanted handling. 220 */ 221 222 pmap_kremove(kva, npages << PAGE_SHIFT); 223 if (kva == emergva) { 224 simple_lock(&pager_map_wanted_lock); 225 emerginuse = FALSE; 226 wakeup(&emergva); 227 simple_unlock(&pager_map_wanted_lock); 228 return; 229 } 230 231 vm_map_lock(pager_map); 232 uvm_unmap_remove(pager_map, kva, kva + size, &entries, NULL, 0); 233 simple_lock(&pager_map_wanted_lock); 234 if (pager_map_wanted) { 235 pager_map_wanted = FALSE; 236 wakeup(pager_map); 237 } 238 simple_unlock(&pager_map_wanted_lock); 239 vm_map_unlock(pager_map); 240 if (entries) 241 uvm_unmap_detach(entries, 0); 242 pmap_update(pmap_kernel()); 243 UVMHIST_LOG(maphist,"<- done",0,0,0,0); 244 } 245 246 /* 247 * interrupt-context iodone handler for nested i/o bufs. 248 * 249 * => must be at splbio(). 250 */ 251 252 void 253 uvm_aio_biodone1(bp) 254 struct buf *bp; 255 { 256 struct buf *mbp = bp->b_private; 257 258 KASSERT(mbp != bp); 259 if (bp->b_flags & B_ERROR) { 260 mbp->b_flags |= B_ERROR; 261 mbp->b_error = bp->b_error; 262 } 263 mbp->b_resid -= bp->b_bcount; 264 pool_put(&bufpool, bp); 265 if (mbp->b_resid == 0) { 266 biodone(mbp); 267 } 268 } 269 270 /* 271 * interrupt-context iodone handler for single-buf i/os 272 * or the top-level buf of a nested-buf i/o. 273 * 274 * => must be at splbio(). 275 */ 276 277 void 278 uvm_aio_biodone(bp) 279 struct buf *bp; 280 { 281 /* reset b_iodone for when this is a single-buf i/o. */ 282 bp->b_iodone = uvm_aio_aiodone; 283 284 simple_lock(&uvm.aiodoned_lock); /* locks uvm.aio_done */ 285 TAILQ_INSERT_TAIL(&uvm.aio_done, bp, b_freelist); 286 wakeup(&uvm.aiodoned); 287 simple_unlock(&uvm.aiodoned_lock); 288 } 289 290 /* 291 * uvm_aio_aiodone: do iodone processing for async i/os. 292 * this should be called in thread context, not interrupt context. 293 */ 294 295 void 296 uvm_aio_aiodone(bp) 297 struct buf *bp; 298 { 299 int npages = bp->b_bufsize >> PAGE_SHIFT; 300 struct vm_page *pg, *pgs[npages]; 301 struct uvm_object *uobj; 302 struct simplelock *slock; 303 int s, i, error, swslot; 304 boolean_t write, swap; 305 UVMHIST_FUNC("uvm_aio_aiodone"); UVMHIST_CALLED(ubchist); 306 UVMHIST_LOG(ubchist, "bp %p", bp, 0,0,0); 307 308 error = (bp->b_flags & B_ERROR) ? (bp->b_error ? bp->b_error : EIO) : 0; 309 write = (bp->b_flags & B_READ) == 0; 310 /* XXXUBC B_NOCACHE is for swap pager, should be done differently */ 311 if (write && !(bp->b_flags & B_NOCACHE) && bioops.io_pageiodone) { 312 (*bioops.io_pageiodone)(bp); 313 } 314 315 uobj = NULL; 316 for (i = 0; i < npages; i++) { 317 pgs[i] = uvm_pageratop((vaddr_t)bp->b_data + (i << PAGE_SHIFT)); 318 UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0); 319 } 320 uvm_pagermapout((vaddr_t)bp->b_data, npages); 321 322 swslot = 0; 323 slock = NULL; 324 pg = pgs[0]; 325 swap = (pg->uanon != NULL && pg->uobject == NULL) || 326 (pg->pqflags & PQ_AOBJ) != 0; 327 if (!swap) { 328 uobj = pg->uobject; 329 slock = &uobj->vmobjlock; 330 simple_lock(slock); 331 uvm_lock_pageq(); 332 } else if (error) { 333 if (pg->uobject != NULL) { 334 swslot = uao_find_swslot(pg->uobject, 335 pg->offset >> PAGE_SHIFT); 336 } else { 337 swslot = pg->uanon->an_swslot; 338 } 339 KASSERT(swslot); 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 /* 347 * for swap i/os, lock each page's object (or anon) 348 * individually since each page may need a different lock. 349 */ 350 351 if (swap) { 352 if (pg->uobject != NULL) { 353 slock = &pg->uobject->vmobjlock; 354 } else { 355 slock = &pg->uanon->an_lock; 356 } 357 simple_lock(slock); 358 uvm_lock_pageq(); 359 } 360 361 /* 362 * process errors. for reads, just mark the page to be freed. 363 * for writes, if the error was ENOMEM, we assume this was 364 * a transient failure so we mark the page dirty so that 365 * we'll try to write it again later. for all other write 366 * errors, we assume the error is permanent, thus the data 367 * in the page is lost. bummer. 368 */ 369 370 if (error) { 371 int slot; 372 if (!write) { 373 pg->flags |= PG_RELEASED; 374 continue; 375 } else if (error == ENOMEM) { 376 if (pg->flags & PG_PAGEOUT) { 377 pg->flags &= ~PG_PAGEOUT; 378 uvmexp.paging--; 379 } 380 pg->flags &= ~PG_CLEAN; 381 uvm_pageactivate(pg); 382 slot = 0; 383 } else 384 slot = SWSLOT_BAD; 385 386 if (swap) { 387 if (pg->uobject != NULL) { 388 int oldslot; 389 oldslot = uao_set_swslot(pg->uobject, 390 pg->offset >> PAGE_SHIFT, slot); 391 KASSERT(oldslot == swslot + i); 392 } else { 393 KASSERT(pg->uanon->an_swslot == 394 swslot + i); 395 pg->uanon->an_swslot = slot; 396 } 397 } 398 } 399 400 /* 401 * if the page is PG_FAKE, this must have been a read to 402 * initialize the page. clear PG_FAKE and activate the page. 403 * we must also clear the pmap "modified" flag since it may 404 * still be set from the page's previous identity. 405 */ 406 407 if (pg->flags & PG_FAKE) { 408 KASSERT(!write); 409 pg->flags &= ~PG_FAKE; 410 uvm_pageactivate(pg); 411 pmap_clear_modify(pg); 412 } 413 414 /* 415 * do accounting for pagedaemon i/o and arrange to free 416 * the pages instead of just unbusying them. 417 */ 418 419 if (pg->flags & PG_PAGEOUT) { 420 pg->flags &= ~PG_PAGEOUT; 421 uvmexp.paging--; 422 uvmexp.pdfreed++; 423 pg->flags |= PG_RELEASED; 424 } 425 426 /* 427 * for swap pages, unlock everything for this page now. 428 */ 429 430 if (swap) { 431 if (pg->uobject == NULL && pg->uanon->an_ref == 0 && 432 (pg->flags & PG_RELEASED) != 0) { 433 uvm_unlock_pageq(); 434 uvm_anon_release(pg->uanon); 435 } else { 436 uvm_page_unbusy(&pg, 1); 437 uvm_unlock_pageq(); 438 simple_unlock(slock); 439 } 440 } 441 } 442 if (!swap) { 443 uvm_page_unbusy(pgs, npages); 444 uvm_unlock_pageq(); 445 simple_unlock(slock); 446 } else { 447 KASSERT(write); 448 449 /* these pages are now only in swap. */ 450 simple_lock(&uvm.swap_data_lock); 451 KASSERT(uvmexp.swpgonly + npages <= uvmexp.swpginuse); 452 if (error != ENOMEM) 453 uvmexp.swpgonly += npages; 454 simple_unlock(&uvm.swap_data_lock); 455 if (error) { 456 if (error != ENOMEM) 457 uvm_swap_markbad(swslot, npages); 458 else 459 uvm_swap_free(swslot, npages); 460 } 461 uvmexp.pdpending--; 462 } 463 s = splbio(); 464 if (write && (bp->b_flags & B_AGE) != 0) { 465 vwakeup(bp); 466 } 467 pool_put(&bufpool, bp); 468 splx(s); 469 } 470