1 /* $NetBSD: uvm_swap.c,v 1.106 2006/09/08 20:58:58 elad Exp $ */ 2 3 /* 4 * Copyright (c) 1995, 1996, 1997 Matthew R. Green 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 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * from: NetBSD: vm_swap.c,v 1.52 1997/12/02 13:47:37 pk Exp 31 * from: Id: uvm_swap.c,v 1.1.2.42 1998/02/02 20:38:06 chuck Exp 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.106 2006/09/08 20:58:58 elad Exp $"); 36 37 #include "fs_nfs.h" 38 #include "opt_uvmhist.h" 39 #include "opt_compat_netbsd.h" 40 #include "opt_ddb.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/buf.h> 45 #include <sys/bufq.h> 46 #include <sys/conf.h> 47 #include <sys/proc.h> 48 #include <sys/namei.h> 49 #include <sys/disklabel.h> 50 #include <sys/errno.h> 51 #include <sys/kernel.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 #include <sys/file.h> 55 #include <sys/extent.h> 56 #include <sys/blist.h> 57 #include <sys/mount.h> 58 #include <sys/pool.h> 59 #include <sys/sa.h> 60 #include <sys/syscallargs.h> 61 #include <sys/swap.h> 62 #include <sys/kauth.h> 63 64 #include <uvm/uvm.h> 65 66 #include <miscfs/specfs/specdev.h> 67 68 /* 69 * uvm_swap.c: manage configuration and i/o to swap space. 70 */ 71 72 /* 73 * swap space is managed in the following way: 74 * 75 * each swap partition or file is described by a "swapdev" structure. 76 * each "swapdev" structure contains a "swapent" structure which contains 77 * information that is passed up to the user (via system calls). 78 * 79 * each swap partition is assigned a "priority" (int) which controls 80 * swap parition usage. 81 * 82 * the system maintains a global data structure describing all swap 83 * partitions/files. there is a sorted LIST of "swappri" structures 84 * which describe "swapdev"'s at that priority. this LIST is headed 85 * by the "swap_priority" global var. each "swappri" contains a 86 * CIRCLEQ of "swapdev" structures at that priority. 87 * 88 * locking: 89 * - swap_syscall_lock (sleep lock): this lock serializes the swapctl 90 * system call and prevents the swap priority list from changing 91 * while we are in the middle of a system call (e.g. SWAP_STATS). 92 * - uvm.swap_data_lock (simple_lock): this lock protects all swap data 93 * structures including the priority list, the swapdev structures, 94 * and the swapmap extent. 95 * 96 * each swap device has the following info: 97 * - swap device in use (could be disabled, preventing future use) 98 * - swap enabled (allows new allocations on swap) 99 * - map info in /dev/drum 100 * - vnode pointer 101 * for swap files only: 102 * - block size 103 * - max byte count in buffer 104 * - buffer 105 * 106 * userland controls and configures swap with the swapctl(2) system call. 107 * the sys_swapctl performs the following operations: 108 * [1] SWAP_NSWAP: returns the number of swap devices currently configured 109 * [2] SWAP_STATS: given a pointer to an array of swapent structures 110 * (passed in via "arg") of a size passed in via "misc" ... we load 111 * the current swap config into the array. The actual work is done 112 * in the uvm_swap_stats(9) function. 113 * [3] SWAP_ON: given a pathname in arg (could be device or file) and a 114 * priority in "misc", start swapping on it. 115 * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device 116 * [5] SWAP_CTL: changes the priority of a swap device (new priority in 117 * "misc") 118 */ 119 120 /* 121 * swapdev: describes a single swap partition/file 122 * 123 * note the following should be true: 124 * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] 125 * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] 126 */ 127 struct swapdev { 128 struct oswapent swd_ose; 129 #define swd_dev swd_ose.ose_dev /* device id */ 130 #define swd_flags swd_ose.ose_flags /* flags:inuse/enable/fake */ 131 #define swd_priority swd_ose.ose_priority /* our priority */ 132 /* also: swd_ose.ose_nblks, swd_ose.ose_inuse */ 133 char *swd_path; /* saved pathname of device */ 134 int swd_pathlen; /* length of pathname */ 135 int swd_npages; /* #pages we can use */ 136 int swd_npginuse; /* #pages in use */ 137 int swd_npgbad; /* #pages bad */ 138 int swd_drumoffset; /* page0 offset in drum */ 139 int swd_drumsize; /* #pages in drum */ 140 blist_t swd_blist; /* blist for this swapdev */ 141 struct vnode *swd_vp; /* backing vnode */ 142 CIRCLEQ_ENTRY(swapdev) swd_next; /* priority circleq */ 143 144 int swd_bsize; /* blocksize (bytes) */ 145 int swd_maxactive; /* max active i/o reqs */ 146 struct bufq_state *swd_tab; /* buffer list */ 147 int swd_active; /* number of active buffers */ 148 }; 149 150 /* 151 * swap device priority entry; the list is kept sorted on `spi_priority'. 152 */ 153 struct swappri { 154 int spi_priority; /* priority */ 155 CIRCLEQ_HEAD(spi_swapdev, swapdev) spi_swapdev; 156 /* circleq of swapdevs at this priority */ 157 LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ 158 }; 159 160 /* 161 * The following two structures are used to keep track of data transfers 162 * on swap devices associated with regular files. 163 * NOTE: this code is more or less a copy of vnd.c; we use the same 164 * structure names here to ease porting.. 165 */ 166 struct vndxfer { 167 struct buf *vx_bp; /* Pointer to parent buffer */ 168 struct swapdev *vx_sdp; 169 int vx_error; 170 int vx_pending; /* # of pending aux buffers */ 171 int vx_flags; 172 #define VX_BUSY 1 173 #define VX_DEAD 2 174 }; 175 176 struct vndbuf { 177 struct buf vb_buf; 178 struct vndxfer *vb_xfer; 179 }; 180 181 182 /* 183 * We keep a of pool vndbuf's and vndxfer structures. 184 */ 185 POOL_INIT(vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", NULL); 186 POOL_INIT(vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", NULL); 187 188 #define getvndxfer(vnx) do { \ 189 int sp = splbio(); \ 190 vnx = pool_get(&vndxfer_pool, PR_WAITOK); \ 191 splx(sp); \ 192 } while (/*CONSTCOND*/ 0) 193 194 #define putvndxfer(vnx) { \ 195 pool_put(&vndxfer_pool, (void *)(vnx)); \ 196 } 197 198 #define getvndbuf(vbp) do { \ 199 int sp = splbio(); \ 200 vbp = pool_get(&vndbuf_pool, PR_WAITOK); \ 201 splx(sp); \ 202 } while (/*CONSTCOND*/ 0) 203 204 #define putvndbuf(vbp) { \ 205 pool_put(&vndbuf_pool, (void *)(vbp)); \ 206 } 207 208 /* 209 * local variables 210 */ 211 static struct extent *swapmap; /* controls the mapping of /dev/drum */ 212 213 MALLOC_DEFINE(M_VMSWAP, "VM swap", "VM swap structures"); 214 215 /* list of all active swap devices [by priority] */ 216 LIST_HEAD(swap_priority, swappri); 217 static struct swap_priority swap_priority; 218 219 /* locks */ 220 static struct lock swap_syscall_lock; 221 222 /* 223 * prototypes 224 */ 225 static struct swapdev *swapdrum_getsdp(int); 226 227 static struct swapdev *swaplist_find(struct vnode *, int); 228 static void swaplist_insert(struct swapdev *, 229 struct swappri *, int); 230 static void swaplist_trim(void); 231 232 static int swap_on(struct lwp *, struct swapdev *); 233 static int swap_off(struct lwp *, struct swapdev *); 234 235 static void uvm_swap_stats_locked(int, struct swapent *, int, register_t *); 236 237 static void sw_reg_strategy(struct swapdev *, struct buf *, int); 238 static void sw_reg_iodone(struct buf *); 239 static void sw_reg_start(struct swapdev *); 240 241 static int uvm_swap_io(struct vm_page **, int, int, int); 242 243 /* 244 * uvm_swap_init: init the swap system data structures and locks 245 * 246 * => called at boot time from init_main.c after the filesystems 247 * are brought up (which happens after uvm_init()) 248 */ 249 void 250 uvm_swap_init(void) 251 { 252 UVMHIST_FUNC("uvm_swap_init"); 253 254 UVMHIST_CALLED(pdhist); 255 /* 256 * first, init the swap list, its counter, and its lock. 257 * then get a handle on the vnode for /dev/drum by using 258 * the its dev_t number ("swapdev", from MD conf.c). 259 */ 260 261 LIST_INIT(&swap_priority); 262 uvmexp.nswapdev = 0; 263 lockinit(&swap_syscall_lock, PVM, "swapsys", 0, 0); 264 simple_lock_init(&uvm.swap_data_lock); 265 266 if (bdevvp(swapdev, &swapdev_vp)) 267 panic("uvm_swap_init: can't get vnode for swap device"); 268 269 /* 270 * create swap block resource map to map /dev/drum. the range 271 * from 1 to INT_MAX allows 2 gigablocks of swap space. note 272 * that block 0 is reserved (used to indicate an allocation 273 * failure, or no allocation). 274 */ 275 swapmap = extent_create("swapmap", 1, INT_MAX, 276 M_VMSWAP, 0, 0, EX_NOWAIT); 277 if (swapmap == 0) 278 panic("uvm_swap_init: extent_create failed"); 279 280 /* 281 * done! 282 */ 283 UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); 284 } 285 286 /* 287 * swaplist functions: functions that operate on the list of swap 288 * devices on the system. 289 */ 290 291 /* 292 * swaplist_insert: insert swap device "sdp" into the global list 293 * 294 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 295 * => caller must provide a newly malloc'd swappri structure (we will 296 * FREE it if we don't need it... this it to prevent malloc blocking 297 * here while adding swap) 298 */ 299 static void 300 swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) 301 { 302 struct swappri *spp, *pspp; 303 UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); 304 305 /* 306 * find entry at or after which to insert the new device. 307 */ 308 pspp = NULL; 309 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 310 if (priority <= spp->spi_priority) 311 break; 312 pspp = spp; 313 } 314 315 /* 316 * new priority? 317 */ 318 if (spp == NULL || spp->spi_priority != priority) { 319 spp = newspp; /* use newspp! */ 320 UVMHIST_LOG(pdhist, "created new swappri = %d", 321 priority, 0, 0, 0); 322 323 spp->spi_priority = priority; 324 CIRCLEQ_INIT(&spp->spi_swapdev); 325 326 if (pspp) 327 LIST_INSERT_AFTER(pspp, spp, spi_swappri); 328 else 329 LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); 330 } else { 331 /* we don't need a new priority structure, free it */ 332 FREE(newspp, M_VMSWAP); 333 } 334 335 /* 336 * priority found (or created). now insert on the priority's 337 * circleq list and bump the total number of swapdevs. 338 */ 339 sdp->swd_priority = priority; 340 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 341 uvmexp.nswapdev++; 342 } 343 344 /* 345 * swaplist_find: find and optionally remove a swap device from the 346 * global list. 347 * 348 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 349 * => we return the swapdev we found (and removed) 350 */ 351 static struct swapdev * 352 swaplist_find(struct vnode *vp, boolean_t remove) 353 { 354 struct swapdev *sdp; 355 struct swappri *spp; 356 357 /* 358 * search the lists for the requested vp 359 */ 360 361 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 362 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 363 if (sdp->swd_vp == vp) { 364 if (remove) { 365 CIRCLEQ_REMOVE(&spp->spi_swapdev, 366 sdp, swd_next); 367 uvmexp.nswapdev--; 368 } 369 return(sdp); 370 } 371 } 372 } 373 return (NULL); 374 } 375 376 377 /* 378 * swaplist_trim: scan priority list for empty priority entries and kill 379 * them. 380 * 381 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 382 */ 383 static void 384 swaplist_trim(void) 385 { 386 struct swappri *spp, *nextspp; 387 388 for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = nextspp) { 389 nextspp = LIST_NEXT(spp, spi_swappri); 390 if (CIRCLEQ_FIRST(&spp->spi_swapdev) != 391 (void *)&spp->spi_swapdev) 392 continue; 393 LIST_REMOVE(spp, spi_swappri); 394 free(spp, M_VMSWAP); 395 } 396 } 397 398 /* 399 * swapdrum_getsdp: given a page offset in /dev/drum, convert it back 400 * to the "swapdev" that maps that section of the drum. 401 * 402 * => each swapdev takes one big contig chunk of the drum 403 * => caller must hold uvm.swap_data_lock 404 */ 405 static struct swapdev * 406 swapdrum_getsdp(int pgno) 407 { 408 struct swapdev *sdp; 409 struct swappri *spp; 410 411 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 412 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 413 if (sdp->swd_flags & SWF_FAKE) 414 continue; 415 if (pgno >= sdp->swd_drumoffset && 416 pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { 417 return sdp; 418 } 419 } 420 } 421 return NULL; 422 } 423 424 425 /* 426 * sys_swapctl: main entry point for swapctl(2) system call 427 * [with two helper functions: swap_on and swap_off] 428 */ 429 int 430 sys_swapctl(struct lwp *l, void *v, register_t *retval) 431 { 432 struct sys_swapctl_args /* { 433 syscallarg(int) cmd; 434 syscallarg(void *) arg; 435 syscallarg(int) misc; 436 } */ *uap = (struct sys_swapctl_args *)v; 437 struct vnode *vp; 438 struct nameidata nd; 439 struct swappri *spp; 440 struct swapdev *sdp; 441 struct swapent *sep; 442 #define SWAP_PATH_MAX (PATH_MAX + 1) 443 char *userpath; 444 size_t len; 445 int error, misc; 446 int priority; 447 UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); 448 449 misc = SCARG(uap, misc); 450 451 /* 452 * ensure serialized syscall access by grabbing the swap_syscall_lock 453 */ 454 lockmgr(&swap_syscall_lock, LK_EXCLUSIVE, NULL); 455 456 userpath = malloc(SWAP_PATH_MAX, M_TEMP, M_WAITOK); 457 /* 458 * we handle the non-priv NSWAP and STATS request first. 459 * 460 * SWAP_NSWAP: return number of config'd swap devices 461 * [can also be obtained with uvmexp sysctl] 462 */ 463 if (SCARG(uap, cmd) == SWAP_NSWAP) { 464 UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d", uvmexp.nswapdev, 465 0, 0, 0); 466 *retval = uvmexp.nswapdev; 467 error = 0; 468 goto out; 469 } 470 471 /* 472 * SWAP_STATS: get stats on current # of configured swap devs 473 * 474 * note that the swap_priority list can't change as long 475 * as we are holding the swap_syscall_lock. we don't want 476 * to grab the uvm.swap_data_lock because we may fault&sleep during 477 * copyout() and we don't want to be holding that lock then! 478 */ 479 if (SCARG(uap, cmd) == SWAP_STATS 480 #if defined(COMPAT_13) 481 || SCARG(uap, cmd) == SWAP_OSTATS 482 #endif 483 ) { 484 if ((size_t)misc > (size_t)uvmexp.nswapdev) 485 misc = uvmexp.nswapdev; 486 #if defined(COMPAT_13) 487 if (SCARG(uap, cmd) == SWAP_OSTATS) 488 len = sizeof(struct oswapent) * misc; 489 else 490 #endif 491 len = sizeof(struct swapent) * misc; 492 sep = (struct swapent *)malloc(len, M_TEMP, M_WAITOK); 493 494 uvm_swap_stats_locked(SCARG(uap, cmd), sep, misc, retval); 495 error = copyout(sep, SCARG(uap, arg), len); 496 497 free(sep, M_TEMP); 498 UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); 499 goto out; 500 } 501 if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { 502 dev_t *devp = (dev_t *)SCARG(uap, arg); 503 504 error = copyout(&dumpdev, devp, sizeof(dumpdev)); 505 goto out; 506 } 507 508 /* 509 * all other requests require superuser privs. verify. 510 */ 511 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SWAPCTL, 512 0, NULL, NULL, NULL))) 513 goto out; 514 515 if (SCARG(uap, cmd) == SWAP_DUMPOFF) { 516 /* drop the current dump device */ 517 dumpdev = NODEV; 518 cpu_dumpconf(); 519 goto out; 520 } 521 522 /* 523 * at this point we expect a path name in arg. we will 524 * use namei() to gain a vnode reference (vref), and lock 525 * the vnode (VOP_LOCK). 526 * 527 * XXX: a NULL arg means use the root vnode pointer (e.g. for 528 * miniroot) 529 */ 530 if (SCARG(uap, arg) == NULL) { 531 vp = rootvp; /* miniroot */ 532 if (vget(vp, LK_EXCLUSIVE)) { 533 error = EBUSY; 534 goto out; 535 } 536 if (SCARG(uap, cmd) == SWAP_ON && 537 copystr("miniroot", userpath, SWAP_PATH_MAX, &len)) 538 panic("swapctl: miniroot copy failed"); 539 } else { 540 int space; 541 char *where; 542 543 if (SCARG(uap, cmd) == SWAP_ON) { 544 if ((error = copyinstr(SCARG(uap, arg), userpath, 545 SWAP_PATH_MAX, &len))) 546 goto out; 547 space = UIO_SYSSPACE; 548 where = userpath; 549 } else { 550 space = UIO_USERSPACE; 551 where = (char *)SCARG(uap, arg); 552 } 553 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, space, where, l); 554 if ((error = namei(&nd))) 555 goto out; 556 vp = nd.ni_vp; 557 } 558 /* note: "vp" is referenced and locked */ 559 560 error = 0; /* assume no error */ 561 switch(SCARG(uap, cmd)) { 562 563 case SWAP_DUMPDEV: 564 if (vp->v_type != VBLK) { 565 error = ENOTBLK; 566 break; 567 } 568 dumpdev = vp->v_rdev; 569 cpu_dumpconf(); 570 break; 571 572 case SWAP_CTL: 573 /* 574 * get new priority, remove old entry (if any) and then 575 * reinsert it in the correct place. finally, prune out 576 * any empty priority structures. 577 */ 578 priority = SCARG(uap, misc); 579 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 580 simple_lock(&uvm.swap_data_lock); 581 if ((sdp = swaplist_find(vp, 1)) == NULL) { 582 error = ENOENT; 583 } else { 584 swaplist_insert(sdp, spp, priority); 585 swaplist_trim(); 586 } 587 simple_unlock(&uvm.swap_data_lock); 588 if (error) 589 free(spp, M_VMSWAP); 590 break; 591 592 case SWAP_ON: 593 594 /* 595 * check for duplicates. if none found, then insert a 596 * dummy entry on the list to prevent someone else from 597 * trying to enable this device while we are working on 598 * it. 599 */ 600 601 priority = SCARG(uap, misc); 602 sdp = malloc(sizeof *sdp, M_VMSWAP, M_WAITOK); 603 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 604 memset(sdp, 0, sizeof(*sdp)); 605 sdp->swd_flags = SWF_FAKE; 606 sdp->swd_vp = vp; 607 sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; 608 bufq_alloc(&sdp->swd_tab, "disksort", BUFQ_SORT_RAWBLOCK); 609 simple_lock(&uvm.swap_data_lock); 610 if (swaplist_find(vp, 0) != NULL) { 611 error = EBUSY; 612 simple_unlock(&uvm.swap_data_lock); 613 bufq_free(sdp->swd_tab); 614 free(sdp, M_VMSWAP); 615 free(spp, M_VMSWAP); 616 break; 617 } 618 swaplist_insert(sdp, spp, priority); 619 simple_unlock(&uvm.swap_data_lock); 620 621 sdp->swd_pathlen = len; 622 sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); 623 if (copystr(userpath, sdp->swd_path, sdp->swd_pathlen, 0) != 0) 624 panic("swapctl: copystr"); 625 626 /* 627 * we've now got a FAKE placeholder in the swap list. 628 * now attempt to enable swap on it. if we fail, undo 629 * what we've done and kill the fake entry we just inserted. 630 * if swap_on is a success, it will clear the SWF_FAKE flag 631 */ 632 633 if ((error = swap_on(l, sdp)) != 0) { 634 simple_lock(&uvm.swap_data_lock); 635 (void) swaplist_find(vp, 1); /* kill fake entry */ 636 swaplist_trim(); 637 simple_unlock(&uvm.swap_data_lock); 638 bufq_free(sdp->swd_tab); 639 free(sdp->swd_path, M_VMSWAP); 640 free(sdp, M_VMSWAP); 641 break; 642 } 643 break; 644 645 case SWAP_OFF: 646 simple_lock(&uvm.swap_data_lock); 647 if ((sdp = swaplist_find(vp, 0)) == NULL) { 648 simple_unlock(&uvm.swap_data_lock); 649 error = ENXIO; 650 break; 651 } 652 653 /* 654 * If a device isn't in use or enabled, we 655 * can't stop swapping from it (again). 656 */ 657 if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { 658 simple_unlock(&uvm.swap_data_lock); 659 error = EBUSY; 660 break; 661 } 662 663 /* 664 * do the real work. 665 */ 666 error = swap_off(l, sdp); 667 break; 668 669 default: 670 error = EINVAL; 671 } 672 673 /* 674 * done! release the ref gained by namei() and unlock. 675 */ 676 vput(vp); 677 678 out: 679 free(userpath, M_TEMP); 680 lockmgr(&swap_syscall_lock, LK_RELEASE, NULL); 681 682 UVMHIST_LOG(pdhist, "<- done! error=%d", error, 0, 0, 0); 683 return (error); 684 } 685 686 /* 687 * swap_stats: implements swapctl(SWAP_STATS). The function is kept 688 * away from sys_swapctl() in order to allow COMPAT_* swapctl() 689 * emulation to use it directly without going through sys_swapctl(). 690 * The problem with using sys_swapctl() there is that it involves 691 * copying the swapent array to the stackgap, and this array's size 692 * is not known at build time. Hence it would not be possible to 693 * ensure it would fit in the stackgap in any case. 694 */ 695 void 696 uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) 697 { 698 699 lockmgr(&swap_syscall_lock, LK_EXCLUSIVE, NULL); 700 uvm_swap_stats_locked(cmd, sep, sec, retval); 701 lockmgr(&swap_syscall_lock, LK_RELEASE, NULL); 702 } 703 704 static void 705 uvm_swap_stats_locked(int cmd, struct swapent *sep, int sec, register_t *retval) 706 { 707 struct swappri *spp; 708 struct swapdev *sdp; 709 int count = 0; 710 711 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 712 for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); 713 sdp != (void *)&spp->spi_swapdev && sec-- > 0; 714 sdp = CIRCLEQ_NEXT(sdp, swd_next)) { 715 /* 716 * backwards compatibility for system call. 717 * note that we use 'struct oswapent' as an 718 * overlay into both 'struct swapdev' and 719 * the userland 'struct swapent', as we 720 * want to retain backwards compatibility 721 * with NetBSD 1.3. 722 */ 723 sdp->swd_ose.ose_inuse = 724 btodb((uint64_t)sdp->swd_npginuse << 725 PAGE_SHIFT); 726 (void)memcpy(sep, &sdp->swd_ose, 727 sizeof(struct oswapent)); 728 729 /* now copy out the path if necessary */ 730 #if defined(COMPAT_13) 731 if (cmd == SWAP_STATS) 732 #endif 733 (void)memcpy(&sep->se_path, sdp->swd_path, 734 sdp->swd_pathlen); 735 736 count++; 737 #if defined(COMPAT_13) 738 if (cmd == SWAP_OSTATS) 739 sep = (struct swapent *) 740 ((struct oswapent *)sep + 1); 741 else 742 #endif 743 sep++; 744 } 745 } 746 747 *retval = count; 748 return; 749 } 750 751 /* 752 * swap_on: attempt to enable a swapdev for swapping. note that the 753 * swapdev is already on the global list, but disabled (marked 754 * SWF_FAKE). 755 * 756 * => we avoid the start of the disk (to protect disk labels) 757 * => we also avoid the miniroot, if we are swapping to root. 758 * => caller should leave uvm.swap_data_lock unlocked, we may lock it 759 * if needed. 760 */ 761 static int 762 swap_on(struct lwp *l, struct swapdev *sdp) 763 { 764 struct vnode *vp; 765 int error, npages, nblocks, size; 766 long addr; 767 u_long result; 768 struct vattr va; 769 #ifdef NFS 770 extern int (**nfsv2_vnodeop_p)(void *); 771 #endif /* NFS */ 772 const struct bdevsw *bdev; 773 dev_t dev; 774 UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); 775 776 /* 777 * we want to enable swapping on sdp. the swd_vp contains 778 * the vnode we want (locked and ref'd), and the swd_dev 779 * contains the dev_t of the file, if it a block device. 780 */ 781 782 vp = sdp->swd_vp; 783 dev = sdp->swd_dev; 784 785 /* 786 * open the swap file (mostly useful for block device files to 787 * let device driver know what is up). 788 * 789 * we skip the open/close for root on swap because the root 790 * has already been opened when root was mounted (mountroot). 791 */ 792 if (vp != rootvp) { 793 if ((error = VOP_OPEN(vp, FREAD|FWRITE, l->l_cred, l))) 794 return (error); 795 } 796 797 /* XXX this only works for block devices */ 798 UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d", dev, major(dev), 0,0); 799 800 /* 801 * we now need to determine the size of the swap area. for 802 * block specials we can call the d_psize function. 803 * for normal files, we must stat [get attrs]. 804 * 805 * we put the result in nblks. 806 * for normal files, we also want the filesystem block size 807 * (which we get with statfs). 808 */ 809 switch (vp->v_type) { 810 case VBLK: 811 bdev = bdevsw_lookup(dev); 812 if (bdev == NULL || bdev->d_psize == NULL || 813 (nblocks = (*bdev->d_psize)(dev)) == -1) { 814 error = ENXIO; 815 goto bad; 816 } 817 break; 818 819 case VREG: 820 if ((error = VOP_GETATTR(vp, &va, l->l_cred, l))) 821 goto bad; 822 nblocks = (int)btodb(va.va_size); 823 if ((error = 824 VFS_STATVFS(vp->v_mount, &vp->v_mount->mnt_stat, l)) != 0) 825 goto bad; 826 827 sdp->swd_bsize = vp->v_mount->mnt_stat.f_iosize; 828 /* 829 * limit the max # of outstanding I/O requests we issue 830 * at any one time. take it easy on NFS servers. 831 */ 832 #ifdef NFS 833 if (vp->v_op == nfsv2_vnodeop_p) 834 sdp->swd_maxactive = 2; /* XXX */ 835 else 836 #endif /* NFS */ 837 sdp->swd_maxactive = 8; /* XXX */ 838 break; 839 840 default: 841 error = ENXIO; 842 goto bad; 843 } 844 845 /* 846 * save nblocks in a safe place and convert to pages. 847 */ 848 849 sdp->swd_ose.ose_nblks = nblocks; 850 npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; 851 852 /* 853 * for block special files, we want to make sure that leave 854 * the disklabel and bootblocks alone, so we arrange to skip 855 * over them (arbitrarily choosing to skip PAGE_SIZE bytes). 856 * note that because of this the "size" can be less than the 857 * actual number of blocks on the device. 858 */ 859 if (vp->v_type == VBLK) { 860 /* we use pages 1 to (size - 1) [inclusive] */ 861 size = npages - 1; 862 addr = 1; 863 } else { 864 /* we use pages 0 to (size - 1) [inclusive] */ 865 size = npages; 866 addr = 0; 867 } 868 869 /* 870 * make sure we have enough blocks for a reasonable sized swap 871 * area. we want at least one page. 872 */ 873 874 if (size < 1) { 875 UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); 876 error = EINVAL; 877 goto bad; 878 } 879 880 UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld\n", dev, size, addr, 0); 881 882 /* 883 * now we need to allocate an extent to manage this swap device 884 */ 885 886 sdp->swd_blist = blist_create(npages); 887 /* mark all expect the `saved' region free. */ 888 blist_free(sdp->swd_blist, addr, size); 889 890 /* 891 * if the vnode we are swapping to is the root vnode 892 * (i.e. we are swapping to the miniroot) then we want 893 * to make sure we don't overwrite it. do a statfs to 894 * find its size and skip over it. 895 */ 896 if (vp == rootvp) { 897 struct mount *mp; 898 struct statvfs *sp; 899 int rootblocks, rootpages; 900 901 mp = rootvnode->v_mount; 902 sp = &mp->mnt_stat; 903 rootblocks = sp->f_blocks * btodb(sp->f_frsize); 904 /* 905 * XXX: sp->f_blocks isn't the total number of 906 * blocks in the filesystem, it's the number of 907 * data blocks. so, our rootblocks almost 908 * definitely underestimates the total size 909 * of the filesystem - how badly depends on the 910 * details of the filesystem type. there isn't 911 * an obvious way to deal with this cleanly 912 * and perfectly, so for now we just pad our 913 * rootblocks estimate with an extra 5 percent. 914 */ 915 rootblocks += (rootblocks >> 5) + 916 (rootblocks >> 6) + 917 (rootblocks >> 7); 918 rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; 919 if (rootpages > size) 920 panic("swap_on: miniroot larger than swap?"); 921 922 if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { 923 panic("swap_on: unable to preserve miniroot"); 924 } 925 926 size -= rootpages; 927 printf("Preserved %d pages of miniroot ", rootpages); 928 printf("leaving %d pages of swap\n", size); 929 } 930 931 /* 932 * add a ref to vp to reflect usage as a swap device. 933 */ 934 vref(vp); 935 936 /* 937 * now add the new swapdev to the drum and enable. 938 */ 939 if (extent_alloc(swapmap, npages, EX_NOALIGN, EX_NOBOUNDARY, 940 EX_WAITOK, &result)) 941 panic("swapdrum_add"); 942 943 sdp->swd_drumoffset = (int)result; 944 sdp->swd_drumsize = npages; 945 sdp->swd_npages = size; 946 simple_lock(&uvm.swap_data_lock); 947 sdp->swd_flags &= ~SWF_FAKE; /* going live */ 948 sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); 949 uvmexp.swpages += size; 950 uvmexp.swpgavail += size; 951 simple_unlock(&uvm.swap_data_lock); 952 return (0); 953 954 /* 955 * failure: clean up and return error. 956 */ 957 958 bad: 959 if (sdp->swd_blist) { 960 blist_destroy(sdp->swd_blist); 961 } 962 if (vp != rootvp) { 963 (void)VOP_CLOSE(vp, FREAD|FWRITE, l->l_cred, l); 964 } 965 return (error); 966 } 967 968 /* 969 * swap_off: stop swapping on swapdev 970 * 971 * => swap data should be locked, we will unlock. 972 */ 973 static int 974 swap_off(struct lwp *l, struct swapdev *sdp) 975 { 976 int npages = sdp->swd_npages; 977 int error = 0; 978 979 UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); 980 UVMHIST_LOG(pdhist, " dev=%x, npages=%d", sdp->swd_dev,npages,0,0); 981 982 /* disable the swap area being removed */ 983 sdp->swd_flags &= ~SWF_ENABLE; 984 uvmexp.swpgavail -= npages; 985 simple_unlock(&uvm.swap_data_lock); 986 987 /* 988 * the idea is to find all the pages that are paged out to this 989 * device, and page them all in. in uvm, swap-backed pageable 990 * memory can take two forms: aobjs and anons. call the 991 * swapoff hook for each subsystem to bring in pages. 992 */ 993 994 if (uao_swap_off(sdp->swd_drumoffset, 995 sdp->swd_drumoffset + sdp->swd_drumsize) || 996 amap_swap_off(sdp->swd_drumoffset, 997 sdp->swd_drumoffset + sdp->swd_drumsize)) { 998 error = ENOMEM; 999 } else if (sdp->swd_npginuse > sdp->swd_npgbad) { 1000 error = EBUSY; 1001 } 1002 1003 if (error) { 1004 simple_lock(&uvm.swap_data_lock); 1005 sdp->swd_flags |= SWF_ENABLE; 1006 uvmexp.swpgavail += npages; 1007 simple_unlock(&uvm.swap_data_lock); 1008 1009 return error; 1010 } 1011 1012 /* 1013 * done with the vnode. 1014 * drop our ref on the vnode before calling VOP_CLOSE() 1015 * so that spec_close() can tell if this is the last close. 1016 */ 1017 vrele(sdp->swd_vp); 1018 if (sdp->swd_vp != rootvp) { 1019 (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, l->l_cred, l); 1020 } 1021 1022 simple_lock(&uvm.swap_data_lock); 1023 uvmexp.swpages -= npages; 1024 uvmexp.swpginuse -= sdp->swd_npgbad; 1025 1026 if (swaplist_find(sdp->swd_vp, 1) == NULL) 1027 panic("swap_off: swapdev not in list"); 1028 swaplist_trim(); 1029 simple_unlock(&uvm.swap_data_lock); 1030 1031 /* 1032 * free all resources! 1033 */ 1034 extent_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize, 1035 EX_WAITOK); 1036 blist_destroy(sdp->swd_blist); 1037 bufq_free(sdp->swd_tab); 1038 free(sdp, M_VMSWAP); 1039 return (0); 1040 } 1041 1042 /* 1043 * /dev/drum interface and i/o functions 1044 */ 1045 1046 /* 1047 * swstrategy: perform I/O on the drum 1048 * 1049 * => we must map the i/o request from the drum to the correct swapdev. 1050 */ 1051 static void 1052 swstrategy(struct buf *bp) 1053 { 1054 struct swapdev *sdp; 1055 struct vnode *vp; 1056 int s, pageno, bn; 1057 UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); 1058 1059 /* 1060 * convert block number to swapdev. note that swapdev can't 1061 * be yanked out from under us because we are holding resources 1062 * in it (i.e. the blocks we are doing I/O on). 1063 */ 1064 pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; 1065 simple_lock(&uvm.swap_data_lock); 1066 sdp = swapdrum_getsdp(pageno); 1067 simple_unlock(&uvm.swap_data_lock); 1068 if (sdp == NULL) { 1069 bp->b_error = EINVAL; 1070 bp->b_flags |= B_ERROR; 1071 biodone(bp); 1072 UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); 1073 return; 1074 } 1075 1076 /* 1077 * convert drum page number to block number on this swapdev. 1078 */ 1079 1080 pageno -= sdp->swd_drumoffset; /* page # on swapdev */ 1081 bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ 1082 1083 UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld", 1084 ((bp->b_flags & B_READ) == 0) ? "write" : "read", 1085 sdp->swd_drumoffset, bn, bp->b_bcount); 1086 1087 /* 1088 * for block devices we finish up here. 1089 * for regular files we have to do more work which we delegate 1090 * to sw_reg_strategy(). 1091 */ 1092 1093 switch (sdp->swd_vp->v_type) { 1094 default: 1095 panic("swstrategy: vnode type 0x%x", sdp->swd_vp->v_type); 1096 1097 case VBLK: 1098 1099 /* 1100 * must convert "bp" from an I/O on /dev/drum to an I/O 1101 * on the swapdev (sdp). 1102 */ 1103 s = splbio(); 1104 bp->b_blkno = bn; /* swapdev block number */ 1105 vp = sdp->swd_vp; /* swapdev vnode pointer */ 1106 bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ 1107 1108 /* 1109 * if we are doing a write, we have to redirect the i/o on 1110 * drum's v_numoutput counter to the swapdevs. 1111 */ 1112 if ((bp->b_flags & B_READ) == 0) { 1113 vwakeup(bp); /* kills one 'v_numoutput' on drum */ 1114 V_INCR_NUMOUTPUT(vp); /* put it on swapdev */ 1115 } 1116 1117 /* 1118 * finally plug in swapdev vnode and start I/O 1119 */ 1120 bp->b_vp = vp; 1121 splx(s); 1122 VOP_STRATEGY(vp, bp); 1123 return; 1124 1125 case VREG: 1126 /* 1127 * delegate to sw_reg_strategy function. 1128 */ 1129 sw_reg_strategy(sdp, bp, bn); 1130 return; 1131 } 1132 /* NOTREACHED */ 1133 } 1134 1135 /* 1136 * swread: the read function for the drum (just a call to physio) 1137 */ 1138 /*ARGSUSED*/ 1139 static int 1140 swread(dev_t dev, struct uio *uio, int ioflag) 1141 { 1142 UVMHIST_FUNC("swread"); UVMHIST_CALLED(pdhist); 1143 1144 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1145 return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); 1146 } 1147 1148 /* 1149 * swwrite: the write function for the drum (just a call to physio) 1150 */ 1151 /*ARGSUSED*/ 1152 static int 1153 swwrite(dev_t dev, struct uio *uio, int ioflag) 1154 { 1155 UVMHIST_FUNC("swwrite"); UVMHIST_CALLED(pdhist); 1156 1157 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1158 return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); 1159 } 1160 1161 const struct bdevsw swap_bdevsw = { 1162 noopen, noclose, swstrategy, noioctl, nodump, nosize, D_OTHER, 1163 }; 1164 1165 const struct cdevsw swap_cdevsw = { 1166 nullopen, nullclose, swread, swwrite, noioctl, 1167 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER, 1168 }; 1169 1170 /* 1171 * sw_reg_strategy: handle swap i/o to regular files 1172 */ 1173 static void 1174 sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) 1175 { 1176 struct vnode *vp; 1177 struct vndxfer *vnx; 1178 daddr_t nbn; 1179 caddr_t addr; 1180 off_t byteoff; 1181 int s, off, nra, error, sz, resid; 1182 UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); 1183 1184 /* 1185 * allocate a vndxfer head for this transfer and point it to 1186 * our buffer. 1187 */ 1188 getvndxfer(vnx); 1189 vnx->vx_flags = VX_BUSY; 1190 vnx->vx_error = 0; 1191 vnx->vx_pending = 0; 1192 vnx->vx_bp = bp; 1193 vnx->vx_sdp = sdp; 1194 1195 /* 1196 * setup for main loop where we read filesystem blocks into 1197 * our buffer. 1198 */ 1199 error = 0; 1200 bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ 1201 addr = bp->b_data; /* current position in buffer */ 1202 byteoff = dbtob((uint64_t)bn); 1203 1204 for (resid = bp->b_resid; resid; resid -= sz) { 1205 struct vndbuf *nbp; 1206 1207 /* 1208 * translate byteoffset into block number. return values: 1209 * vp = vnode of underlying device 1210 * nbn = new block number (on underlying vnode dev) 1211 * nra = num blocks we can read-ahead (excludes requested 1212 * block) 1213 */ 1214 nra = 0; 1215 error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, 1216 &vp, &nbn, &nra); 1217 1218 if (error == 0 && nbn == (daddr_t)-1) { 1219 /* 1220 * this used to just set error, but that doesn't 1221 * do the right thing. Instead, it causes random 1222 * memory errors. The panic() should remain until 1223 * this condition doesn't destabilize the system. 1224 */ 1225 #if 1 1226 panic("sw_reg_strategy: swap to sparse file"); 1227 #else 1228 error = EIO; /* failure */ 1229 #endif 1230 } 1231 1232 /* 1233 * punt if there was an error or a hole in the file. 1234 * we must wait for any i/o ops we have already started 1235 * to finish before returning. 1236 * 1237 * XXX we could deal with holes here but it would be 1238 * a hassle (in the write case). 1239 */ 1240 if (error) { 1241 s = splbio(); 1242 vnx->vx_error = error; /* pass error up */ 1243 goto out; 1244 } 1245 1246 /* 1247 * compute the size ("sz") of this transfer (in bytes). 1248 */ 1249 off = byteoff % sdp->swd_bsize; 1250 sz = (1 + nra) * sdp->swd_bsize - off; 1251 if (sz > resid) 1252 sz = resid; 1253 1254 UVMHIST_LOG(pdhist, "sw_reg_strategy: " 1255 "vp %p/%p offset 0x%x/0x%x", 1256 sdp->swd_vp, vp, byteoff, nbn); 1257 1258 /* 1259 * now get a buf structure. note that the vb_buf is 1260 * at the front of the nbp structure so that you can 1261 * cast pointers between the two structure easily. 1262 */ 1263 getvndbuf(nbp); 1264 BUF_INIT(&nbp->vb_buf); 1265 nbp->vb_buf.b_flags = bp->b_flags | B_CALL; 1266 nbp->vb_buf.b_bcount = sz; 1267 nbp->vb_buf.b_bufsize = sz; 1268 nbp->vb_buf.b_error = 0; 1269 nbp->vb_buf.b_data = addr; 1270 nbp->vb_buf.b_lblkno = 0; 1271 nbp->vb_buf.b_blkno = nbn + btodb(off); 1272 nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; 1273 nbp->vb_buf.b_iodone = sw_reg_iodone; 1274 nbp->vb_buf.b_vp = vp; 1275 if (vp->v_type == VBLK) { 1276 nbp->vb_buf.b_dev = vp->v_rdev; 1277 } 1278 1279 nbp->vb_xfer = vnx; /* patch it back in to vnx */ 1280 1281 /* 1282 * Just sort by block number 1283 */ 1284 s = splbio(); 1285 if (vnx->vx_error != 0) { 1286 putvndbuf(nbp); 1287 goto out; 1288 } 1289 vnx->vx_pending++; 1290 1291 /* sort it in and start I/O if we are not over our limit */ 1292 BUFQ_PUT(sdp->swd_tab, &nbp->vb_buf); 1293 sw_reg_start(sdp); 1294 splx(s); 1295 1296 /* 1297 * advance to the next I/O 1298 */ 1299 byteoff += sz; 1300 addr += sz; 1301 } 1302 1303 s = splbio(); 1304 1305 out: /* Arrive here at splbio */ 1306 vnx->vx_flags &= ~VX_BUSY; 1307 if (vnx->vx_pending == 0) { 1308 if (vnx->vx_error != 0) { 1309 bp->b_error = vnx->vx_error; 1310 bp->b_flags |= B_ERROR; 1311 } 1312 putvndxfer(vnx); 1313 biodone(bp); 1314 } 1315 splx(s); 1316 } 1317 1318 /* 1319 * sw_reg_start: start an I/O request on the requested swapdev 1320 * 1321 * => reqs are sorted by b_rawblkno (above) 1322 */ 1323 static void 1324 sw_reg_start(struct swapdev *sdp) 1325 { 1326 struct buf *bp; 1327 UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); 1328 1329 /* recursion control */ 1330 if ((sdp->swd_flags & SWF_BUSY) != 0) 1331 return; 1332 1333 sdp->swd_flags |= SWF_BUSY; 1334 1335 while (sdp->swd_active < sdp->swd_maxactive) { 1336 bp = BUFQ_GET(sdp->swd_tab); 1337 if (bp == NULL) 1338 break; 1339 sdp->swd_active++; 1340 1341 UVMHIST_LOG(pdhist, 1342 "sw_reg_start: bp %p vp %p blkno %p cnt %lx", 1343 bp, bp->b_vp, bp->b_blkno, bp->b_bcount); 1344 if ((bp->b_flags & B_READ) == 0) 1345 V_INCR_NUMOUTPUT(bp->b_vp); 1346 1347 VOP_STRATEGY(bp->b_vp, bp); 1348 } 1349 sdp->swd_flags &= ~SWF_BUSY; 1350 } 1351 1352 /* 1353 * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup 1354 * 1355 * => note that we can recover the vndbuf struct by casting the buf ptr 1356 */ 1357 static void 1358 sw_reg_iodone(struct buf *bp) 1359 { 1360 struct vndbuf *vbp = (struct vndbuf *) bp; 1361 struct vndxfer *vnx = vbp->vb_xfer; 1362 struct buf *pbp = vnx->vx_bp; /* parent buffer */ 1363 struct swapdev *sdp = vnx->vx_sdp; 1364 int s, resid, error; 1365 UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); 1366 1367 UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p", 1368 vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); 1369 UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", 1370 vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); 1371 1372 /* 1373 * protect vbp at splbio and update. 1374 */ 1375 1376 s = splbio(); 1377 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 1378 pbp->b_resid -= resid; 1379 vnx->vx_pending--; 1380 1381 if (vbp->vb_buf.b_flags & B_ERROR) { 1382 /* pass error upward */ 1383 error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; 1384 UVMHIST_LOG(pdhist, " got error=%d !", error, 0, 0, 0); 1385 vnx->vx_error = error; 1386 } 1387 1388 /* 1389 * kill vbp structure 1390 */ 1391 putvndbuf(vbp); 1392 1393 /* 1394 * wrap up this transaction if it has run to completion or, in 1395 * case of an error, when all auxiliary buffers have returned. 1396 */ 1397 if (vnx->vx_error != 0) { 1398 /* pass error upward */ 1399 pbp->b_flags |= B_ERROR; 1400 pbp->b_error = vnx->vx_error; 1401 if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { 1402 putvndxfer(vnx); 1403 biodone(pbp); 1404 } 1405 } else if (pbp->b_resid == 0) { 1406 KASSERT(vnx->vx_pending == 0); 1407 if ((vnx->vx_flags & VX_BUSY) == 0) { 1408 UVMHIST_LOG(pdhist, " iodone error=%d !", 1409 pbp, vnx->vx_error, 0, 0); 1410 putvndxfer(vnx); 1411 biodone(pbp); 1412 } 1413 } 1414 1415 /* 1416 * done! start next swapdev I/O if one is pending 1417 */ 1418 sdp->swd_active--; 1419 sw_reg_start(sdp); 1420 splx(s); 1421 } 1422 1423 1424 /* 1425 * uvm_swap_alloc: allocate space on swap 1426 * 1427 * => allocation is done "round robin" down the priority list, as we 1428 * allocate in a priority we "rotate" the circle queue. 1429 * => space can be freed with uvm_swap_free 1430 * => we return the page slot number in /dev/drum (0 == invalid slot) 1431 * => we lock uvm.swap_data_lock 1432 * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM 1433 */ 1434 int 1435 uvm_swap_alloc(int *nslots /* IN/OUT */, boolean_t lessok) 1436 { 1437 struct swapdev *sdp; 1438 struct swappri *spp; 1439 UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); 1440 1441 /* 1442 * no swap devices configured yet? definite failure. 1443 */ 1444 if (uvmexp.nswapdev < 1) 1445 return 0; 1446 1447 /* 1448 * lock data lock, convert slots into blocks, and enter loop 1449 */ 1450 simple_lock(&uvm.swap_data_lock); 1451 1452 ReTry: /* XXXMRG */ 1453 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 1454 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 1455 uint64_t result; 1456 1457 /* if it's not enabled, then we can't swap from it */ 1458 if ((sdp->swd_flags & SWF_ENABLE) == 0) 1459 continue; 1460 if (sdp->swd_npginuse + *nslots > sdp->swd_npages) 1461 continue; 1462 result = blist_alloc(sdp->swd_blist, *nslots); 1463 if (result == BLIST_NONE) { 1464 continue; 1465 } 1466 KASSERT(result < sdp->swd_drumsize); 1467 1468 /* 1469 * successful allocation! now rotate the circleq. 1470 */ 1471 CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); 1472 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 1473 sdp->swd_npginuse += *nslots; 1474 uvmexp.swpginuse += *nslots; 1475 simple_unlock(&uvm.swap_data_lock); 1476 /* done! return drum slot number */ 1477 UVMHIST_LOG(pdhist, 1478 "success! returning %d slots starting at %d", 1479 *nslots, result + sdp->swd_drumoffset, 0, 0); 1480 return (result + sdp->swd_drumoffset); 1481 } 1482 } 1483 1484 /* XXXMRG: BEGIN HACK */ 1485 if (*nslots > 1 && lessok) { 1486 *nslots = 1; 1487 /* XXXMRG: ugh! blist should support this for us */ 1488 goto ReTry; 1489 } 1490 /* XXXMRG: END HACK */ 1491 1492 simple_unlock(&uvm.swap_data_lock); 1493 return 0; 1494 } 1495 1496 boolean_t 1497 uvm_swapisfull(void) 1498 { 1499 boolean_t rv; 1500 1501 simple_lock(&uvm.swap_data_lock); 1502 KASSERT(uvmexp.swpgonly <= uvmexp.swpages); 1503 rv = (uvmexp.swpgonly >= uvmexp.swpgavail); 1504 simple_unlock(&uvm.swap_data_lock); 1505 1506 return (rv); 1507 } 1508 1509 /* 1510 * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors 1511 * 1512 * => we lock uvm.swap_data_lock 1513 */ 1514 void 1515 uvm_swap_markbad(int startslot, int nslots) 1516 { 1517 struct swapdev *sdp; 1518 UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); 1519 1520 simple_lock(&uvm.swap_data_lock); 1521 sdp = swapdrum_getsdp(startslot); 1522 KASSERT(sdp != NULL); 1523 1524 /* 1525 * we just keep track of how many pages have been marked bad 1526 * in this device, to make everything add up in swap_off(). 1527 * we assume here that the range of slots will all be within 1528 * one swap device. 1529 */ 1530 1531 KASSERT(uvmexp.swpgonly >= nslots); 1532 uvmexp.swpgonly -= nslots; 1533 sdp->swd_npgbad += nslots; 1534 UVMHIST_LOG(pdhist, "now %d bad", sdp->swd_npgbad, 0,0,0); 1535 simple_unlock(&uvm.swap_data_lock); 1536 } 1537 1538 /* 1539 * uvm_swap_free: free swap slots 1540 * 1541 * => this can be all or part of an allocation made by uvm_swap_alloc 1542 * => we lock uvm.swap_data_lock 1543 */ 1544 void 1545 uvm_swap_free(int startslot, int nslots) 1546 { 1547 struct swapdev *sdp; 1548 UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); 1549 1550 UVMHIST_LOG(pdhist, "freeing %d slots starting at %d", nslots, 1551 startslot, 0, 0); 1552 1553 /* 1554 * ignore attempts to free the "bad" slot. 1555 */ 1556 1557 if (startslot == SWSLOT_BAD) { 1558 return; 1559 } 1560 1561 /* 1562 * convert drum slot offset back to sdp, free the blocks 1563 * in the extent, and return. must hold pri lock to do 1564 * lookup and access the extent. 1565 */ 1566 1567 simple_lock(&uvm.swap_data_lock); 1568 sdp = swapdrum_getsdp(startslot); 1569 KASSERT(uvmexp.nswapdev >= 1); 1570 KASSERT(sdp != NULL); 1571 KASSERT(sdp->swd_npginuse >= nslots); 1572 blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); 1573 sdp->swd_npginuse -= nslots; 1574 uvmexp.swpginuse -= nslots; 1575 simple_unlock(&uvm.swap_data_lock); 1576 } 1577 1578 /* 1579 * uvm_swap_put: put any number of pages into a contig place on swap 1580 * 1581 * => can be sync or async 1582 */ 1583 1584 int 1585 uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) 1586 { 1587 int error; 1588 1589 error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | 1590 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1591 return error; 1592 } 1593 1594 /* 1595 * uvm_swap_get: get a single page from swap 1596 * 1597 * => usually a sync op (from fault) 1598 */ 1599 1600 int 1601 uvm_swap_get(struct vm_page *page, int swslot, int flags) 1602 { 1603 int error; 1604 1605 uvmexp.nswget++; 1606 KASSERT(flags & PGO_SYNCIO); 1607 if (swslot == SWSLOT_BAD) { 1608 return EIO; 1609 } 1610 1611 error = uvm_swap_io(&page, swslot, 1, B_READ | 1612 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1613 if (error == 0) { 1614 1615 /* 1616 * this page is no longer only in swap. 1617 */ 1618 1619 simple_lock(&uvm.swap_data_lock); 1620 KASSERT(uvmexp.swpgonly > 0); 1621 uvmexp.swpgonly--; 1622 simple_unlock(&uvm.swap_data_lock); 1623 } 1624 return error; 1625 } 1626 1627 /* 1628 * uvm_swap_io: do an i/o operation to swap 1629 */ 1630 1631 static int 1632 uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) 1633 { 1634 daddr_t startblk; 1635 struct buf *bp; 1636 vaddr_t kva; 1637 int error, s, mapinflags; 1638 boolean_t write, async; 1639 UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); 1640 1641 UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d", 1642 startslot, npages, flags, 0); 1643 1644 write = (flags & B_READ) == 0; 1645 async = (flags & B_ASYNC) != 0; 1646 1647 /* 1648 * convert starting drum slot to block number 1649 */ 1650 1651 startblk = btodb((uint64_t)startslot << PAGE_SHIFT); 1652 1653 /* 1654 * first, map the pages into the kernel. 1655 */ 1656 1657 mapinflags = !write ? 1658 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : 1659 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; 1660 kva = uvm_pagermapin(pps, npages, mapinflags); 1661 1662 /* 1663 * now allocate a buf for the i/o. 1664 */ 1665 1666 bp = getiobuf(); 1667 1668 /* 1669 * fill in the bp/sbp. we currently route our i/o through 1670 * /dev/drum's vnode [swapdev_vp]. 1671 */ 1672 1673 bp->b_flags = B_BUSY | B_NOCACHE | (flags & (B_READ|B_ASYNC)); 1674 bp->b_proc = &proc0; /* XXX */ 1675 bp->b_vnbufs.le_next = NOLIST; 1676 bp->b_data = (caddr_t)kva; 1677 bp->b_blkno = startblk; 1678 bp->b_vp = swapdev_vp; 1679 bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; 1680 1681 /* 1682 * bump v_numoutput (counter of number of active outputs). 1683 */ 1684 1685 if (write) { 1686 s = splbio(); 1687 V_INCR_NUMOUTPUT(swapdev_vp); 1688 splx(s); 1689 } 1690 1691 /* 1692 * for async ops we must set up the iodone handler. 1693 */ 1694 1695 if (async) { 1696 bp->b_flags |= B_CALL; 1697 bp->b_iodone = uvm_aio_biodone; 1698 UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); 1699 if (curproc == uvm.pagedaemon_proc) 1700 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1701 else 1702 BIO_SETPRIO(bp, BPRIO_TIMELIMITED); 1703 } else { 1704 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1705 } 1706 UVMHIST_LOG(pdhist, 1707 "about to start io: data = %p blkno = 0x%x, bcount = %ld", 1708 bp->b_data, bp->b_blkno, bp->b_bcount, 0); 1709 1710 /* 1711 * now we start the I/O, and if async, return. 1712 */ 1713 1714 VOP_STRATEGY(swapdev_vp, bp); 1715 if (async) 1716 return 0; 1717 1718 /* 1719 * must be sync i/o. wait for it to finish 1720 */ 1721 1722 error = biowait(bp); 1723 1724 /* 1725 * kill the pager mapping 1726 */ 1727 1728 uvm_pagermapout(kva, npages); 1729 1730 /* 1731 * now dispose of the buf and we're done. 1732 */ 1733 1734 s = splbio(); 1735 if (write) 1736 vwakeup(bp); 1737 putiobuf(bp); 1738 splx(s); 1739 UVMHIST_LOG(pdhist, "<- done (sync) error=%d", error, 0, 0, 0); 1740 return (error); 1741 } 1742