1 /* $NetBSD: uvm_swap.c,v 1.152 2010/07/09 08:13:33 hannken Exp $ */ 2 3 /* 4 * Copyright (c) 1995, 1996, 1997, 2009 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 * 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, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from: NetBSD: vm_swap.c,v 1.52 1997/12/02 13:47:37 pk Exp 29 * from: Id: uvm_swap.c,v 1.1.2.42 1998/02/02 20:38:06 chuck Exp 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.152 2010/07/09 08:13:33 hannken Exp $"); 34 35 #include "opt_uvmhist.h" 36 #include "opt_compat_netbsd.h" 37 #include "opt_ddb.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/buf.h> 42 #include <sys/bufq.h> 43 #include <sys/conf.h> 44 #include <sys/proc.h> 45 #include <sys/namei.h> 46 #include <sys/disklabel.h> 47 #include <sys/errno.h> 48 #include <sys/kernel.h> 49 #include <sys/malloc.h> 50 #include <sys/vnode.h> 51 #include <sys/file.h> 52 #include <sys/vmem.h> 53 #include <sys/blist.h> 54 #include <sys/mount.h> 55 #include <sys/pool.h> 56 #include <sys/syscallargs.h> 57 #include <sys/swap.h> 58 #include <sys/kauth.h> 59 #include <sys/sysctl.h> 60 #include <sys/workqueue.h> 61 62 #include <uvm/uvm.h> 63 64 #include <miscfs/specfs/specdev.h> 65 66 /* 67 * uvm_swap.c: manage configuration and i/o to swap space. 68 */ 69 70 /* 71 * swap space is managed in the following way: 72 * 73 * each swap partition or file is described by a "swapdev" structure. 74 * each "swapdev" structure contains a "swapent" structure which contains 75 * information that is passed up to the user (via system calls). 76 * 77 * each swap partition is assigned a "priority" (int) which controls 78 * swap parition usage. 79 * 80 * the system maintains a global data structure describing all swap 81 * partitions/files. there is a sorted LIST of "swappri" structures 82 * which describe "swapdev"'s at that priority. this LIST is headed 83 * by the "swap_priority" global var. each "swappri" contains a 84 * CIRCLEQ of "swapdev" structures at that priority. 85 * 86 * locking: 87 * - swap_syscall_lock (krwlock_t): this lock serializes the swapctl 88 * system call and prevents the swap priority list from changing 89 * while we are in the middle of a system call (e.g. SWAP_STATS). 90 * - uvm_swap_data_lock (kmutex_t): this lock protects all swap data 91 * structures including the priority list, the swapdev structures, 92 * and the swapmap arena. 93 * 94 * each swap device has the following info: 95 * - swap device in use (could be disabled, preventing future use) 96 * - swap enabled (allows new allocations on swap) 97 * - map info in /dev/drum 98 * - vnode pointer 99 * for swap files only: 100 * - block size 101 * - max byte count in buffer 102 * - buffer 103 * 104 * userland controls and configures swap with the swapctl(2) system call. 105 * the sys_swapctl performs the following operations: 106 * [1] SWAP_NSWAP: returns the number of swap devices currently configured 107 * [2] SWAP_STATS: given a pointer to an array of swapent structures 108 * (passed in via "arg") of a size passed in via "misc" ... we load 109 * the current swap config into the array. The actual work is done 110 * in the uvm_swap_stats(9) function. 111 * [3] SWAP_ON: given a pathname in arg (could be device or file) and a 112 * priority in "misc", start swapping on it. 113 * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device 114 * [5] SWAP_CTL: changes the priority of a swap device (new priority in 115 * "misc") 116 */ 117 118 /* 119 * swapdev: describes a single swap partition/file 120 * 121 * note the following should be true: 122 * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] 123 * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] 124 */ 125 struct swapdev { 126 dev_t swd_dev; /* device id */ 127 int swd_flags; /* flags:inuse/enable/fake */ 128 int swd_priority; /* our priority */ 129 int swd_nblks; /* blocks in this device */ 130 char *swd_path; /* saved pathname of device */ 131 int swd_pathlen; /* length of pathname */ 132 int swd_npages; /* #pages we can use */ 133 int swd_npginuse; /* #pages in use */ 134 int swd_npgbad; /* #pages bad */ 135 int swd_drumoffset; /* page0 offset in drum */ 136 int swd_drumsize; /* #pages in drum */ 137 blist_t swd_blist; /* blist for this swapdev */ 138 struct vnode *swd_vp; /* backing vnode */ 139 CIRCLEQ_ENTRY(swapdev) swd_next; /* priority circleq */ 140 141 int swd_bsize; /* blocksize (bytes) */ 142 int swd_maxactive; /* max active i/o reqs */ 143 struct bufq_state *swd_tab; /* buffer list */ 144 int swd_active; /* number of active buffers */ 145 }; 146 147 /* 148 * swap device priority entry; the list is kept sorted on `spi_priority'. 149 */ 150 struct swappri { 151 int spi_priority; /* priority */ 152 CIRCLEQ_HEAD(spi_swapdev, swapdev) spi_swapdev; 153 /* circleq of swapdevs at this priority */ 154 LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ 155 }; 156 157 /* 158 * The following two structures are used to keep track of data transfers 159 * on swap devices associated with regular files. 160 * NOTE: this code is more or less a copy of vnd.c; we use the same 161 * structure names here to ease porting.. 162 */ 163 struct vndxfer { 164 struct buf *vx_bp; /* Pointer to parent buffer */ 165 struct swapdev *vx_sdp; 166 int vx_error; 167 int vx_pending; /* # of pending aux buffers */ 168 int vx_flags; 169 #define VX_BUSY 1 170 #define VX_DEAD 2 171 }; 172 173 struct vndbuf { 174 struct buf vb_buf; 175 struct vndxfer *vb_xfer; 176 }; 177 178 /* 179 * NetBSD 1.3 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit 180 * dev_t and has no se_path[] member. 181 */ 182 struct swapent13 { 183 int32_t se13_dev; /* device id */ 184 int se13_flags; /* flags */ 185 int se13_nblks; /* total blocks */ 186 int se13_inuse; /* blocks in use */ 187 int se13_priority; /* priority of this device */ 188 }; 189 190 /* 191 * NetBSD 5.0 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit 192 * dev_t. 193 */ 194 struct swapent50 { 195 int32_t se50_dev; /* device id */ 196 int se50_flags; /* flags */ 197 int se50_nblks; /* total blocks */ 198 int se50_inuse; /* blocks in use */ 199 int se50_priority; /* priority of this device */ 200 char se50_path[PATH_MAX+1]; /* path name */ 201 }; 202 203 /* 204 * We keep a of pool vndbuf's and vndxfer structures. 205 */ 206 static struct pool vndxfer_pool, vndbuf_pool; 207 208 /* 209 * local variables 210 */ 211 MALLOC_DEFINE(M_VMSWAP, "VM swap", "VM swap structures"); 212 static vmem_t *swapmap; /* controls the mapping of /dev/drum */ 213 214 /* list of all active swap devices [by priority] */ 215 LIST_HEAD(swap_priority, swappri); 216 static struct swap_priority swap_priority; 217 218 /* locks */ 219 static krwlock_t swap_syscall_lock; 220 221 /* workqueue and use counter for swap to regular files */ 222 static int sw_reg_count = 0; 223 static struct workqueue *sw_reg_workqueue; 224 225 /* tuneables */ 226 u_int uvm_swapisfull_factor = 99; 227 228 /* 229 * prototypes 230 */ 231 static struct swapdev *swapdrum_getsdp(int); 232 233 static struct swapdev *swaplist_find(struct vnode *, bool); 234 static void swaplist_insert(struct swapdev *, 235 struct swappri *, int); 236 static void swaplist_trim(void); 237 238 static int swap_on(struct lwp *, struct swapdev *); 239 static int swap_off(struct lwp *, struct swapdev *); 240 241 static void uvm_swap_stats_locked(int, struct swapent *, int, register_t *); 242 243 static void sw_reg_strategy(struct swapdev *, struct buf *, int); 244 static void sw_reg_biodone(struct buf *); 245 static void sw_reg_iodone(struct work *wk, void *dummy); 246 static void sw_reg_start(struct swapdev *); 247 248 static int uvm_swap_io(struct vm_page **, int, int, int); 249 250 /* 251 * uvm_swap_init: init the swap system data structures and locks 252 * 253 * => called at boot time from init_main.c after the filesystems 254 * are brought up (which happens after uvm_init()) 255 */ 256 void 257 uvm_swap_init(void) 258 { 259 UVMHIST_FUNC("uvm_swap_init"); 260 261 UVMHIST_CALLED(pdhist); 262 /* 263 * first, init the swap list, its counter, and its lock. 264 * then get a handle on the vnode for /dev/drum by using 265 * the its dev_t number ("swapdev", from MD conf.c). 266 */ 267 268 LIST_INIT(&swap_priority); 269 uvmexp.nswapdev = 0; 270 rw_init(&swap_syscall_lock); 271 mutex_init(&uvm_swap_data_lock, MUTEX_DEFAULT, IPL_NONE); 272 273 if (bdevvp(swapdev, &swapdev_vp)) 274 panic("%s: can't get vnode for swap device", __func__); 275 if (vn_lock(swapdev_vp, LK_EXCLUSIVE | LK_RETRY)) 276 panic("%s: can't lock swap device", __func__); 277 if (VOP_OPEN(swapdev_vp, FREAD | FWRITE, NOCRED)) 278 panic("%s: can't open swap device", __func__); 279 VOP_UNLOCK(swapdev_vp); 280 281 /* 282 * create swap block resource map to map /dev/drum. the range 283 * from 1 to INT_MAX allows 2 gigablocks of swap space. note 284 * that block 0 is reserved (used to indicate an allocation 285 * failure, or no allocation). 286 */ 287 swapmap = vmem_create("swapmap", 1, INT_MAX - 1, 1, NULL, NULL, NULL, 0, 288 VM_NOSLEEP, IPL_NONE); 289 if (swapmap == 0) { 290 panic("%s: vmem_create failed", __func__); 291 } 292 293 pool_init(&vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", 294 NULL, IPL_BIO); 295 pool_init(&vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", 296 NULL, IPL_BIO); 297 298 UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); 299 } 300 301 /* 302 * swaplist functions: functions that operate on the list of swap 303 * devices on the system. 304 */ 305 306 /* 307 * swaplist_insert: insert swap device "sdp" into the global list 308 * 309 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 310 * => caller must provide a newly malloc'd swappri structure (we will 311 * FREE it if we don't need it... this it to prevent malloc blocking 312 * here while adding swap) 313 */ 314 static void 315 swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) 316 { 317 struct swappri *spp, *pspp; 318 UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); 319 320 /* 321 * find entry at or after which to insert the new device. 322 */ 323 pspp = NULL; 324 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 325 if (priority <= spp->spi_priority) 326 break; 327 pspp = spp; 328 } 329 330 /* 331 * new priority? 332 */ 333 if (spp == NULL || spp->spi_priority != priority) { 334 spp = newspp; /* use newspp! */ 335 UVMHIST_LOG(pdhist, "created new swappri = %d", 336 priority, 0, 0, 0); 337 338 spp->spi_priority = priority; 339 CIRCLEQ_INIT(&spp->spi_swapdev); 340 341 if (pspp) 342 LIST_INSERT_AFTER(pspp, spp, spi_swappri); 343 else 344 LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); 345 } else { 346 /* we don't need a new priority structure, free it */ 347 free(newspp, M_VMSWAP); 348 } 349 350 /* 351 * priority found (or created). now insert on the priority's 352 * circleq list and bump the total number of swapdevs. 353 */ 354 sdp->swd_priority = priority; 355 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 356 uvmexp.nswapdev++; 357 } 358 359 /* 360 * swaplist_find: find and optionally remove a swap device from the 361 * global list. 362 * 363 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 364 * => we return the swapdev we found (and removed) 365 */ 366 static struct swapdev * 367 swaplist_find(struct vnode *vp, bool remove) 368 { 369 struct swapdev *sdp; 370 struct swappri *spp; 371 372 /* 373 * search the lists for the requested vp 374 */ 375 376 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 377 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 378 if (sdp->swd_vp == vp) { 379 if (remove) { 380 CIRCLEQ_REMOVE(&spp->spi_swapdev, 381 sdp, swd_next); 382 uvmexp.nswapdev--; 383 } 384 return(sdp); 385 } 386 } 387 } 388 return (NULL); 389 } 390 391 /* 392 * swaplist_trim: scan priority list for empty priority entries and kill 393 * them. 394 * 395 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 396 */ 397 static void 398 swaplist_trim(void) 399 { 400 struct swappri *spp, *nextspp; 401 402 for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = nextspp) { 403 nextspp = LIST_NEXT(spp, spi_swappri); 404 if (CIRCLEQ_FIRST(&spp->spi_swapdev) != 405 (void *)&spp->spi_swapdev) 406 continue; 407 LIST_REMOVE(spp, spi_swappri); 408 free(spp, M_VMSWAP); 409 } 410 } 411 412 /* 413 * swapdrum_getsdp: given a page offset in /dev/drum, convert it back 414 * to the "swapdev" that maps that section of the drum. 415 * 416 * => each swapdev takes one big contig chunk of the drum 417 * => caller must hold uvm_swap_data_lock 418 */ 419 static struct swapdev * 420 swapdrum_getsdp(int pgno) 421 { 422 struct swapdev *sdp; 423 struct swappri *spp; 424 425 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 426 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 427 if (sdp->swd_flags & SWF_FAKE) 428 continue; 429 if (pgno >= sdp->swd_drumoffset && 430 pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { 431 return sdp; 432 } 433 } 434 } 435 return NULL; 436 } 437 438 439 /* 440 * sys_swapctl: main entry point for swapctl(2) system call 441 * [with two helper functions: swap_on and swap_off] 442 */ 443 int 444 sys_swapctl(struct lwp *l, const struct sys_swapctl_args *uap, register_t *retval) 445 { 446 /* { 447 syscallarg(int) cmd; 448 syscallarg(void *) arg; 449 syscallarg(int) misc; 450 } */ 451 struct vnode *vp; 452 struct nameidata nd; 453 struct swappri *spp; 454 struct swapdev *sdp; 455 struct swapent *sep; 456 #define SWAP_PATH_MAX (PATH_MAX + 1) 457 char *userpath; 458 size_t len; 459 int error, misc; 460 int priority; 461 UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); 462 463 misc = SCARG(uap, misc); 464 465 /* 466 * ensure serialized syscall access by grabbing the swap_syscall_lock 467 */ 468 rw_enter(&swap_syscall_lock, RW_WRITER); 469 470 userpath = malloc(SWAP_PATH_MAX, M_TEMP, M_WAITOK); 471 /* 472 * we handle the non-priv NSWAP and STATS request first. 473 * 474 * SWAP_NSWAP: return number of config'd swap devices 475 * [can also be obtained with uvmexp sysctl] 476 */ 477 if (SCARG(uap, cmd) == SWAP_NSWAP) { 478 UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d", uvmexp.nswapdev, 479 0, 0, 0); 480 *retval = uvmexp.nswapdev; 481 error = 0; 482 goto out; 483 } 484 485 /* 486 * SWAP_STATS: get stats on current # of configured swap devs 487 * 488 * note that the swap_priority list can't change as long 489 * as we are holding the swap_syscall_lock. we don't want 490 * to grab the uvm_swap_data_lock because we may fault&sleep during 491 * copyout() and we don't want to be holding that lock then! 492 */ 493 if (SCARG(uap, cmd) == SWAP_STATS 494 #if defined(COMPAT_50) 495 || SCARG(uap, cmd) == SWAP_STATS50 496 #endif 497 #if defined(COMPAT_13) 498 || SCARG(uap, cmd) == SWAP_STATS13 499 #endif 500 ) { 501 if ((size_t)misc > (size_t)uvmexp.nswapdev) 502 misc = uvmexp.nswapdev; 503 #if defined(COMPAT_13) 504 if (SCARG(uap, cmd) == SWAP_STATS13) 505 len = sizeof(struct swapent13) * misc; 506 else 507 #endif 508 #if defined(COMPAT_50) 509 if (SCARG(uap, cmd) == SWAP_STATS50) 510 len = sizeof(struct swapent50) * misc; 511 else 512 #endif 513 len = sizeof(struct swapent) * misc; 514 sep = (struct swapent *)malloc(len, M_TEMP, M_WAITOK); 515 516 uvm_swap_stats_locked(SCARG(uap, cmd), sep, misc, retval); 517 error = copyout(sep, SCARG(uap, arg), len); 518 519 free(sep, M_TEMP); 520 UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); 521 goto out; 522 } 523 if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { 524 dev_t *devp = (dev_t *)SCARG(uap, arg); 525 526 error = copyout(&dumpdev, devp, sizeof(dumpdev)); 527 goto out; 528 } 529 530 /* 531 * all other requests require superuser privs. verify. 532 */ 533 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SWAPCTL, 534 0, NULL, NULL, NULL))) 535 goto out; 536 537 if (SCARG(uap, cmd) == SWAP_DUMPOFF) { 538 /* drop the current dump device */ 539 dumpdev = NODEV; 540 dumpcdev = NODEV; 541 cpu_dumpconf(); 542 goto out; 543 } 544 545 /* 546 * at this point we expect a path name in arg. we will 547 * use namei() to gain a vnode reference (vref), and lock 548 * the vnode (VOP_LOCK). 549 * 550 * XXX: a NULL arg means use the root vnode pointer (e.g. for 551 * miniroot) 552 */ 553 if (SCARG(uap, arg) == NULL) { 554 vp = rootvp; /* miniroot */ 555 vref(vp); 556 if (vn_lock(vp, LK_EXCLUSIVE)) { 557 vrele(vp); 558 error = EBUSY; 559 goto out; 560 } 561 if (SCARG(uap, cmd) == SWAP_ON && 562 copystr("miniroot", userpath, SWAP_PATH_MAX, &len)) 563 panic("swapctl: miniroot copy failed"); 564 } else { 565 int space; 566 char *where; 567 568 if (SCARG(uap, cmd) == SWAP_ON) { 569 if ((error = copyinstr(SCARG(uap, arg), userpath, 570 SWAP_PATH_MAX, &len))) 571 goto out; 572 space = UIO_SYSSPACE; 573 where = userpath; 574 } else { 575 space = UIO_USERSPACE; 576 where = (char *)SCARG(uap, arg); 577 } 578 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, 579 space, where); 580 if ((error = namei(&nd))) 581 goto out; 582 vp = nd.ni_vp; 583 } 584 /* note: "vp" is referenced and locked */ 585 586 error = 0; /* assume no error */ 587 switch(SCARG(uap, cmd)) { 588 589 case SWAP_DUMPDEV: 590 if (vp->v_type != VBLK) { 591 error = ENOTBLK; 592 break; 593 } 594 if (bdevsw_lookup(vp->v_rdev)) { 595 dumpdev = vp->v_rdev; 596 dumpcdev = devsw_blk2chr(dumpdev); 597 } else 598 dumpdev = NODEV; 599 cpu_dumpconf(); 600 break; 601 602 case SWAP_CTL: 603 /* 604 * get new priority, remove old entry (if any) and then 605 * reinsert it in the correct place. finally, prune out 606 * any empty priority structures. 607 */ 608 priority = SCARG(uap, misc); 609 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 610 mutex_enter(&uvm_swap_data_lock); 611 if ((sdp = swaplist_find(vp, true)) == NULL) { 612 error = ENOENT; 613 } else { 614 swaplist_insert(sdp, spp, priority); 615 swaplist_trim(); 616 } 617 mutex_exit(&uvm_swap_data_lock); 618 if (error) 619 free(spp, M_VMSWAP); 620 break; 621 622 case SWAP_ON: 623 624 /* 625 * check for duplicates. if none found, then insert a 626 * dummy entry on the list to prevent someone else from 627 * trying to enable this device while we are working on 628 * it. 629 */ 630 631 priority = SCARG(uap, misc); 632 sdp = malloc(sizeof *sdp, M_VMSWAP, M_WAITOK); 633 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 634 memset(sdp, 0, sizeof(*sdp)); 635 sdp->swd_flags = SWF_FAKE; 636 sdp->swd_vp = vp; 637 sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; 638 bufq_alloc(&sdp->swd_tab, "disksort", BUFQ_SORT_RAWBLOCK); 639 mutex_enter(&uvm_swap_data_lock); 640 if (swaplist_find(vp, false) != NULL) { 641 error = EBUSY; 642 mutex_exit(&uvm_swap_data_lock); 643 bufq_free(sdp->swd_tab); 644 free(sdp, M_VMSWAP); 645 free(spp, M_VMSWAP); 646 break; 647 } 648 swaplist_insert(sdp, spp, priority); 649 mutex_exit(&uvm_swap_data_lock); 650 651 sdp->swd_pathlen = len; 652 sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); 653 if (copystr(userpath, sdp->swd_path, sdp->swd_pathlen, 0) != 0) 654 panic("swapctl: copystr"); 655 656 /* 657 * we've now got a FAKE placeholder in the swap list. 658 * now attempt to enable swap on it. if we fail, undo 659 * what we've done and kill the fake entry we just inserted. 660 * if swap_on is a success, it will clear the SWF_FAKE flag 661 */ 662 663 if ((error = swap_on(l, sdp)) != 0) { 664 mutex_enter(&uvm_swap_data_lock); 665 (void) swaplist_find(vp, true); /* kill fake entry */ 666 swaplist_trim(); 667 mutex_exit(&uvm_swap_data_lock); 668 bufq_free(sdp->swd_tab); 669 free(sdp->swd_path, M_VMSWAP); 670 free(sdp, M_VMSWAP); 671 break; 672 } 673 break; 674 675 case SWAP_OFF: 676 mutex_enter(&uvm_swap_data_lock); 677 if ((sdp = swaplist_find(vp, false)) == NULL) { 678 mutex_exit(&uvm_swap_data_lock); 679 error = ENXIO; 680 break; 681 } 682 683 /* 684 * If a device isn't in use or enabled, we 685 * can't stop swapping from it (again). 686 */ 687 if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { 688 mutex_exit(&uvm_swap_data_lock); 689 error = EBUSY; 690 break; 691 } 692 693 /* 694 * do the real work. 695 */ 696 error = swap_off(l, sdp); 697 break; 698 699 default: 700 error = EINVAL; 701 } 702 703 /* 704 * done! release the ref gained by namei() and unlock. 705 */ 706 vput(vp); 707 708 out: 709 free(userpath, M_TEMP); 710 rw_exit(&swap_syscall_lock); 711 712 UVMHIST_LOG(pdhist, "<- done! error=%d", error, 0, 0, 0); 713 return (error); 714 } 715 716 /* 717 * swap_stats: implements swapctl(SWAP_STATS). The function is kept 718 * away from sys_swapctl() in order to allow COMPAT_* swapctl() 719 * emulation to use it directly without going through sys_swapctl(). 720 * The problem with using sys_swapctl() there is that it involves 721 * copying the swapent array to the stackgap, and this array's size 722 * is not known at build time. Hence it would not be possible to 723 * ensure it would fit in the stackgap in any case. 724 */ 725 void 726 uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) 727 { 728 729 rw_enter(&swap_syscall_lock, RW_READER); 730 uvm_swap_stats_locked(cmd, sep, sec, retval); 731 rw_exit(&swap_syscall_lock); 732 } 733 734 static void 735 uvm_swap_stats_locked(int cmd, struct swapent *sep, int sec, register_t *retval) 736 { 737 struct swappri *spp; 738 struct swapdev *sdp; 739 int count = 0; 740 741 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 742 for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); 743 sdp != (void *)&spp->spi_swapdev && sec-- > 0; 744 sdp = CIRCLEQ_NEXT(sdp, swd_next)) { 745 int inuse; 746 747 /* 748 * backwards compatibility for system call. 749 * For NetBSD 1.3 and 5.0, we have to use 750 * the 32 bit dev_t. For 5.0 and -current 751 * we have to add the path. 752 */ 753 inuse = btodb((uint64_t)sdp->swd_npginuse << 754 PAGE_SHIFT); 755 756 #if defined(COMPAT_13) || defined(COMPAT_50) 757 if (cmd == SWAP_STATS) { 758 #endif 759 sep->se_dev = sdp->swd_dev; 760 sep->se_flags = sdp->swd_flags; 761 sep->se_nblks = sdp->swd_nblks; 762 sep->se_inuse = inuse; 763 sep->se_priority = sdp->swd_priority; 764 memcpy(&sep->se_path, sdp->swd_path, 765 sizeof sep->se_path); 766 sep++; 767 #if defined(COMPAT_13) 768 } else if (cmd == SWAP_STATS13) { 769 struct swapent13 *sep13 = 770 (struct swapent13 *)sep; 771 772 sep13->se13_dev = sdp->swd_dev; 773 sep13->se13_flags = sdp->swd_flags; 774 sep13->se13_nblks = sdp->swd_nblks; 775 sep13->se13_inuse = inuse; 776 sep13->se13_priority = sdp->swd_priority; 777 sep = (struct swapent *)(sep13 + 1); 778 #endif 779 #if defined(COMPAT_50) 780 } else if (cmd == SWAP_STATS50) { 781 struct swapent50 *sep50 = 782 (struct swapent50 *)sep; 783 784 sep50->se50_dev = sdp->swd_dev; 785 sep50->se50_flags = sdp->swd_flags; 786 sep50->se50_nblks = sdp->swd_nblks; 787 sep50->se50_inuse = inuse; 788 sep50->se50_priority = sdp->swd_priority; 789 memcpy(&sep50->se50_path, sdp->swd_path, 790 sizeof sep50->se50_path); 791 sep = (struct swapent *)(sep50 + 1); 792 #endif 793 #if defined(COMPAT_13) || defined(COMPAT_50) 794 } 795 #endif 796 count++; 797 } 798 } 799 800 *retval = count; 801 return; 802 } 803 804 /* 805 * swap_on: attempt to enable a swapdev for swapping. note that the 806 * swapdev is already on the global list, but disabled (marked 807 * SWF_FAKE). 808 * 809 * => we avoid the start of the disk (to protect disk labels) 810 * => we also avoid the miniroot, if we are swapping to root. 811 * => caller should leave uvm_swap_data_lock unlocked, we may lock it 812 * if needed. 813 */ 814 static int 815 swap_on(struct lwp *l, struct swapdev *sdp) 816 { 817 struct vnode *vp; 818 int error, npages, nblocks, size; 819 long addr; 820 u_long result; 821 struct vattr va; 822 const struct bdevsw *bdev; 823 dev_t dev; 824 UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); 825 826 /* 827 * we want to enable swapping on sdp. the swd_vp contains 828 * the vnode we want (locked and ref'd), and the swd_dev 829 * contains the dev_t of the file, if it a block device. 830 */ 831 832 vp = sdp->swd_vp; 833 dev = sdp->swd_dev; 834 835 /* 836 * open the swap file (mostly useful for block device files to 837 * let device driver know what is up). 838 * 839 * we skip the open/close for root on swap because the root 840 * has already been opened when root was mounted (mountroot). 841 */ 842 if (vp != rootvp) { 843 if ((error = VOP_OPEN(vp, FREAD|FWRITE, l->l_cred))) 844 return (error); 845 } 846 847 /* XXX this only works for block devices */ 848 UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d", dev, major(dev), 0,0); 849 850 /* 851 * we now need to determine the size of the swap area. for 852 * block specials we can call the d_psize function. 853 * for normal files, we must stat [get attrs]. 854 * 855 * we put the result in nblks. 856 * for normal files, we also want the filesystem block size 857 * (which we get with statfs). 858 */ 859 switch (vp->v_type) { 860 case VBLK: 861 bdev = bdevsw_lookup(dev); 862 if (bdev == NULL || bdev->d_psize == NULL || 863 (nblocks = (*bdev->d_psize)(dev)) == -1) { 864 error = ENXIO; 865 goto bad; 866 } 867 break; 868 869 case VREG: 870 if ((error = VOP_GETATTR(vp, &va, l->l_cred))) 871 goto bad; 872 nblocks = (int)btodb(va.va_size); 873 sdp->swd_bsize = 1 << vp->v_mount->mnt_fs_bshift; 874 /* 875 * limit the max # of outstanding I/O requests we issue 876 * at any one time. take it easy on NFS servers. 877 */ 878 if (vp->v_tag == VT_NFS) 879 sdp->swd_maxactive = 2; /* XXX */ 880 else 881 sdp->swd_maxactive = 8; /* XXX */ 882 break; 883 884 default: 885 error = ENXIO; 886 goto bad; 887 } 888 889 /* 890 * save nblocks in a safe place and convert to pages. 891 */ 892 893 sdp->swd_nblks = nblocks; 894 npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; 895 896 /* 897 * for block special files, we want to make sure that leave 898 * the disklabel and bootblocks alone, so we arrange to skip 899 * over them (arbitrarily choosing to skip PAGE_SIZE bytes). 900 * note that because of this the "size" can be less than the 901 * actual number of blocks on the device. 902 */ 903 if (vp->v_type == VBLK) { 904 /* we use pages 1 to (size - 1) [inclusive] */ 905 size = npages - 1; 906 addr = 1; 907 } else { 908 /* we use pages 0 to (size - 1) [inclusive] */ 909 size = npages; 910 addr = 0; 911 } 912 913 /* 914 * make sure we have enough blocks for a reasonable sized swap 915 * area. we want at least one page. 916 */ 917 918 if (size < 1) { 919 UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); 920 error = EINVAL; 921 goto bad; 922 } 923 924 UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld\n", dev, size, addr, 0); 925 926 /* 927 * now we need to allocate an extent to manage this swap device 928 */ 929 930 sdp->swd_blist = blist_create(npages); 931 /* mark all expect the `saved' region free. */ 932 blist_free(sdp->swd_blist, addr, size); 933 934 /* 935 * if the vnode we are swapping to is the root vnode 936 * (i.e. we are swapping to the miniroot) then we want 937 * to make sure we don't overwrite it. do a statfs to 938 * find its size and skip over it. 939 */ 940 if (vp == rootvp) { 941 struct mount *mp; 942 struct statvfs *sp; 943 int rootblocks, rootpages; 944 945 mp = rootvnode->v_mount; 946 sp = &mp->mnt_stat; 947 rootblocks = sp->f_blocks * btodb(sp->f_frsize); 948 /* 949 * XXX: sp->f_blocks isn't the total number of 950 * blocks in the filesystem, it's the number of 951 * data blocks. so, our rootblocks almost 952 * definitely underestimates the total size 953 * of the filesystem - how badly depends on the 954 * details of the filesystem type. there isn't 955 * an obvious way to deal with this cleanly 956 * and perfectly, so for now we just pad our 957 * rootblocks estimate with an extra 5 percent. 958 */ 959 rootblocks += (rootblocks >> 5) + 960 (rootblocks >> 6) + 961 (rootblocks >> 7); 962 rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; 963 if (rootpages > size) 964 panic("swap_on: miniroot larger than swap?"); 965 966 if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { 967 panic("swap_on: unable to preserve miniroot"); 968 } 969 970 size -= rootpages; 971 printf("Preserved %d pages of miniroot ", rootpages); 972 printf("leaving %d pages of swap\n", size); 973 } 974 975 /* 976 * add a ref to vp to reflect usage as a swap device. 977 */ 978 vref(vp); 979 980 /* 981 * now add the new swapdev to the drum and enable. 982 */ 983 result = vmem_alloc(swapmap, npages, VM_BESTFIT | VM_SLEEP); 984 if (result == 0) 985 panic("swapdrum_add"); 986 /* 987 * If this is the first regular swap create the workqueue. 988 * => Protected by swap_syscall_lock. 989 */ 990 if (vp->v_type != VBLK) { 991 if (sw_reg_count++ == 0) { 992 KASSERT(sw_reg_workqueue == NULL); 993 if (workqueue_create(&sw_reg_workqueue, "swapiod", 994 sw_reg_iodone, NULL, PRIBIO, IPL_BIO, 0) != 0) 995 panic("%s: workqueue_create failed", __func__); 996 } 997 } 998 999 sdp->swd_drumoffset = (int)result; 1000 sdp->swd_drumsize = npages; 1001 sdp->swd_npages = size; 1002 mutex_enter(&uvm_swap_data_lock); 1003 sdp->swd_flags &= ~SWF_FAKE; /* going live */ 1004 sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); 1005 uvmexp.swpages += size; 1006 uvmexp.swpgavail += size; 1007 mutex_exit(&uvm_swap_data_lock); 1008 return (0); 1009 1010 /* 1011 * failure: clean up and return error. 1012 */ 1013 1014 bad: 1015 if (sdp->swd_blist) { 1016 blist_destroy(sdp->swd_blist); 1017 } 1018 if (vp != rootvp) { 1019 (void)VOP_CLOSE(vp, FREAD|FWRITE, l->l_cred); 1020 } 1021 return (error); 1022 } 1023 1024 /* 1025 * swap_off: stop swapping on swapdev 1026 * 1027 * => swap data should be locked, we will unlock. 1028 */ 1029 static int 1030 swap_off(struct lwp *l, struct swapdev *sdp) 1031 { 1032 int npages = sdp->swd_npages; 1033 int error = 0; 1034 1035 UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); 1036 UVMHIST_LOG(pdhist, " dev=%x, npages=%d", sdp->swd_dev,npages,0,0); 1037 1038 /* disable the swap area being removed */ 1039 sdp->swd_flags &= ~SWF_ENABLE; 1040 uvmexp.swpgavail -= npages; 1041 mutex_exit(&uvm_swap_data_lock); 1042 1043 /* 1044 * the idea is to find all the pages that are paged out to this 1045 * device, and page them all in. in uvm, swap-backed pageable 1046 * memory can take two forms: aobjs and anons. call the 1047 * swapoff hook for each subsystem to bring in pages. 1048 */ 1049 1050 if (uao_swap_off(sdp->swd_drumoffset, 1051 sdp->swd_drumoffset + sdp->swd_drumsize) || 1052 amap_swap_off(sdp->swd_drumoffset, 1053 sdp->swd_drumoffset + sdp->swd_drumsize)) { 1054 error = ENOMEM; 1055 } else if (sdp->swd_npginuse > sdp->swd_npgbad) { 1056 error = EBUSY; 1057 } 1058 1059 if (error) { 1060 mutex_enter(&uvm_swap_data_lock); 1061 sdp->swd_flags |= SWF_ENABLE; 1062 uvmexp.swpgavail += npages; 1063 mutex_exit(&uvm_swap_data_lock); 1064 1065 return error; 1066 } 1067 1068 /* 1069 * If this is the last regular swap destroy the workqueue. 1070 * => Protected by swap_syscall_lock. 1071 */ 1072 if (sdp->swd_vp->v_type != VBLK) { 1073 KASSERT(sw_reg_count > 0); 1074 KASSERT(sw_reg_workqueue != NULL); 1075 if (--sw_reg_count == 0) { 1076 workqueue_destroy(sw_reg_workqueue); 1077 sw_reg_workqueue = NULL; 1078 } 1079 } 1080 1081 /* 1082 * done with the vnode. 1083 * drop our ref on the vnode before calling VOP_CLOSE() 1084 * so that spec_close() can tell if this is the last close. 1085 */ 1086 vrele(sdp->swd_vp); 1087 if (sdp->swd_vp != rootvp) { 1088 (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, l->l_cred); 1089 } 1090 1091 mutex_enter(&uvm_swap_data_lock); 1092 uvmexp.swpages -= npages; 1093 uvmexp.swpginuse -= sdp->swd_npgbad; 1094 1095 if (swaplist_find(sdp->swd_vp, true) == NULL) 1096 panic("%s: swapdev not in list", __func__); 1097 swaplist_trim(); 1098 mutex_exit(&uvm_swap_data_lock); 1099 1100 /* 1101 * free all resources! 1102 */ 1103 vmem_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize); 1104 blist_destroy(sdp->swd_blist); 1105 bufq_free(sdp->swd_tab); 1106 free(sdp, M_VMSWAP); 1107 return (0); 1108 } 1109 1110 /* 1111 * /dev/drum interface and i/o functions 1112 */ 1113 1114 /* 1115 * swstrategy: perform I/O on the drum 1116 * 1117 * => we must map the i/o request from the drum to the correct swapdev. 1118 */ 1119 static void 1120 swstrategy(struct buf *bp) 1121 { 1122 struct swapdev *sdp; 1123 struct vnode *vp; 1124 int pageno, bn; 1125 UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); 1126 1127 /* 1128 * convert block number to swapdev. note that swapdev can't 1129 * be yanked out from under us because we are holding resources 1130 * in it (i.e. the blocks we are doing I/O on). 1131 */ 1132 pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; 1133 mutex_enter(&uvm_swap_data_lock); 1134 sdp = swapdrum_getsdp(pageno); 1135 mutex_exit(&uvm_swap_data_lock); 1136 if (sdp == NULL) { 1137 bp->b_error = EINVAL; 1138 biodone(bp); 1139 UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); 1140 return; 1141 } 1142 1143 /* 1144 * convert drum page number to block number on this swapdev. 1145 */ 1146 1147 pageno -= sdp->swd_drumoffset; /* page # on swapdev */ 1148 bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ 1149 1150 UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld", 1151 ((bp->b_flags & B_READ) == 0) ? "write" : "read", 1152 sdp->swd_drumoffset, bn, bp->b_bcount); 1153 1154 /* 1155 * for block devices we finish up here. 1156 * for regular files we have to do more work which we delegate 1157 * to sw_reg_strategy(). 1158 */ 1159 1160 vp = sdp->swd_vp; /* swapdev vnode pointer */ 1161 switch (vp->v_type) { 1162 default: 1163 panic("%s: vnode type 0x%x", __func__, vp->v_type); 1164 1165 case VBLK: 1166 1167 /* 1168 * must convert "bp" from an I/O on /dev/drum to an I/O 1169 * on the swapdev (sdp). 1170 */ 1171 bp->b_blkno = bn; /* swapdev block number */ 1172 bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ 1173 1174 /* 1175 * if we are doing a write, we have to redirect the i/o on 1176 * drum's v_numoutput counter to the swapdevs. 1177 */ 1178 if ((bp->b_flags & B_READ) == 0) { 1179 mutex_enter(bp->b_objlock); 1180 vwakeup(bp); /* kills one 'v_numoutput' on drum */ 1181 mutex_exit(bp->b_objlock); 1182 mutex_enter(&vp->v_interlock); 1183 vp->v_numoutput++; /* put it on swapdev */ 1184 mutex_exit(&vp->v_interlock); 1185 } 1186 1187 /* 1188 * finally plug in swapdev vnode and start I/O 1189 */ 1190 bp->b_vp = vp; 1191 bp->b_objlock = &vp->v_interlock; 1192 VOP_STRATEGY(vp, bp); 1193 return; 1194 1195 case VREG: 1196 /* 1197 * delegate to sw_reg_strategy function. 1198 */ 1199 sw_reg_strategy(sdp, bp, bn); 1200 return; 1201 } 1202 /* NOTREACHED */ 1203 } 1204 1205 /* 1206 * swread: the read function for the drum (just a call to physio) 1207 */ 1208 /*ARGSUSED*/ 1209 static int 1210 swread(dev_t dev, struct uio *uio, int ioflag) 1211 { 1212 UVMHIST_FUNC("swread"); UVMHIST_CALLED(pdhist); 1213 1214 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1215 return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); 1216 } 1217 1218 /* 1219 * swwrite: the write function for the drum (just a call to physio) 1220 */ 1221 /*ARGSUSED*/ 1222 static int 1223 swwrite(dev_t dev, struct uio *uio, int ioflag) 1224 { 1225 UVMHIST_FUNC("swwrite"); UVMHIST_CALLED(pdhist); 1226 1227 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1228 return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); 1229 } 1230 1231 const struct bdevsw swap_bdevsw = { 1232 nullopen, nullclose, swstrategy, noioctl, nodump, nosize, D_OTHER, 1233 }; 1234 1235 const struct cdevsw swap_cdevsw = { 1236 nullopen, nullclose, swread, swwrite, noioctl, 1237 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER, 1238 }; 1239 1240 /* 1241 * sw_reg_strategy: handle swap i/o to regular files 1242 */ 1243 static void 1244 sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) 1245 { 1246 struct vnode *vp; 1247 struct vndxfer *vnx; 1248 daddr_t nbn; 1249 char *addr; 1250 off_t byteoff; 1251 int s, off, nra, error, sz, resid; 1252 UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); 1253 1254 /* 1255 * allocate a vndxfer head for this transfer and point it to 1256 * our buffer. 1257 */ 1258 vnx = pool_get(&vndxfer_pool, PR_WAITOK); 1259 vnx->vx_flags = VX_BUSY; 1260 vnx->vx_error = 0; 1261 vnx->vx_pending = 0; 1262 vnx->vx_bp = bp; 1263 vnx->vx_sdp = sdp; 1264 1265 /* 1266 * setup for main loop where we read filesystem blocks into 1267 * our buffer. 1268 */ 1269 error = 0; 1270 bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ 1271 addr = bp->b_data; /* current position in buffer */ 1272 byteoff = dbtob((uint64_t)bn); 1273 1274 for (resid = bp->b_resid; resid; resid -= sz) { 1275 struct vndbuf *nbp; 1276 1277 /* 1278 * translate byteoffset into block number. return values: 1279 * vp = vnode of underlying device 1280 * nbn = new block number (on underlying vnode dev) 1281 * nra = num blocks we can read-ahead (excludes requested 1282 * block) 1283 */ 1284 nra = 0; 1285 error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, 1286 &vp, &nbn, &nra); 1287 1288 if (error == 0 && nbn == (daddr_t)-1) { 1289 /* 1290 * this used to just set error, but that doesn't 1291 * do the right thing. Instead, it causes random 1292 * memory errors. The panic() should remain until 1293 * this condition doesn't destabilize the system. 1294 */ 1295 #if 1 1296 panic("%s: swap to sparse file", __func__); 1297 #else 1298 error = EIO; /* failure */ 1299 #endif 1300 } 1301 1302 /* 1303 * punt if there was an error or a hole in the file. 1304 * we must wait for any i/o ops we have already started 1305 * to finish before returning. 1306 * 1307 * XXX we could deal with holes here but it would be 1308 * a hassle (in the write case). 1309 */ 1310 if (error) { 1311 s = splbio(); 1312 vnx->vx_error = error; /* pass error up */ 1313 goto out; 1314 } 1315 1316 /* 1317 * compute the size ("sz") of this transfer (in bytes). 1318 */ 1319 off = byteoff % sdp->swd_bsize; 1320 sz = (1 + nra) * sdp->swd_bsize - off; 1321 if (sz > resid) 1322 sz = resid; 1323 1324 UVMHIST_LOG(pdhist, "sw_reg_strategy: " 1325 "vp %p/%p offset 0x%x/0x%x", 1326 sdp->swd_vp, vp, byteoff, nbn); 1327 1328 /* 1329 * now get a buf structure. note that the vb_buf is 1330 * at the front of the nbp structure so that you can 1331 * cast pointers between the two structure easily. 1332 */ 1333 nbp = pool_get(&vndbuf_pool, PR_WAITOK); 1334 buf_init(&nbp->vb_buf); 1335 nbp->vb_buf.b_flags = bp->b_flags; 1336 nbp->vb_buf.b_cflags = bp->b_cflags; 1337 nbp->vb_buf.b_oflags = bp->b_oflags; 1338 nbp->vb_buf.b_bcount = sz; 1339 nbp->vb_buf.b_bufsize = sz; 1340 nbp->vb_buf.b_error = 0; 1341 nbp->vb_buf.b_data = addr; 1342 nbp->vb_buf.b_lblkno = 0; 1343 nbp->vb_buf.b_blkno = nbn + btodb(off); 1344 nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; 1345 nbp->vb_buf.b_iodone = sw_reg_biodone; 1346 nbp->vb_buf.b_vp = vp; 1347 nbp->vb_buf.b_objlock = &vp->v_interlock; 1348 if (vp->v_type == VBLK) { 1349 nbp->vb_buf.b_dev = vp->v_rdev; 1350 } 1351 1352 nbp->vb_xfer = vnx; /* patch it back in to vnx */ 1353 1354 /* 1355 * Just sort by block number 1356 */ 1357 s = splbio(); 1358 if (vnx->vx_error != 0) { 1359 buf_destroy(&nbp->vb_buf); 1360 pool_put(&vndbuf_pool, nbp); 1361 goto out; 1362 } 1363 vnx->vx_pending++; 1364 1365 /* sort it in and start I/O if we are not over our limit */ 1366 /* XXXAD locking */ 1367 bufq_put(sdp->swd_tab, &nbp->vb_buf); 1368 sw_reg_start(sdp); 1369 splx(s); 1370 1371 /* 1372 * advance to the next I/O 1373 */ 1374 byteoff += sz; 1375 addr += sz; 1376 } 1377 1378 s = splbio(); 1379 1380 out: /* Arrive here at splbio */ 1381 vnx->vx_flags &= ~VX_BUSY; 1382 if (vnx->vx_pending == 0) { 1383 error = vnx->vx_error; 1384 pool_put(&vndxfer_pool, vnx); 1385 bp->b_error = error; 1386 biodone(bp); 1387 } 1388 splx(s); 1389 } 1390 1391 /* 1392 * sw_reg_start: start an I/O request on the requested swapdev 1393 * 1394 * => reqs are sorted by b_rawblkno (above) 1395 */ 1396 static void 1397 sw_reg_start(struct swapdev *sdp) 1398 { 1399 struct buf *bp; 1400 struct vnode *vp; 1401 UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); 1402 1403 /* recursion control */ 1404 if ((sdp->swd_flags & SWF_BUSY) != 0) 1405 return; 1406 1407 sdp->swd_flags |= SWF_BUSY; 1408 1409 while (sdp->swd_active < sdp->swd_maxactive) { 1410 bp = bufq_get(sdp->swd_tab); 1411 if (bp == NULL) 1412 break; 1413 sdp->swd_active++; 1414 1415 UVMHIST_LOG(pdhist, 1416 "sw_reg_start: bp %p vp %p blkno %p cnt %lx", 1417 bp, bp->b_vp, bp->b_blkno, bp->b_bcount); 1418 vp = bp->b_vp; 1419 KASSERT(bp->b_objlock == &vp->v_interlock); 1420 if ((bp->b_flags & B_READ) == 0) { 1421 mutex_enter(&vp->v_interlock); 1422 vp->v_numoutput++; 1423 mutex_exit(&vp->v_interlock); 1424 } 1425 VOP_STRATEGY(vp, bp); 1426 } 1427 sdp->swd_flags &= ~SWF_BUSY; 1428 } 1429 1430 /* 1431 * sw_reg_biodone: one of our i/o's has completed 1432 */ 1433 static void 1434 sw_reg_biodone(struct buf *bp) 1435 { 1436 workqueue_enqueue(sw_reg_workqueue, &bp->b_work, NULL); 1437 } 1438 1439 /* 1440 * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup 1441 * 1442 * => note that we can recover the vndbuf struct by casting the buf ptr 1443 */ 1444 static void 1445 sw_reg_iodone(struct work *wk, void *dummy) 1446 { 1447 struct vndbuf *vbp = (void *)wk; 1448 struct vndxfer *vnx = vbp->vb_xfer; 1449 struct buf *pbp = vnx->vx_bp; /* parent buffer */ 1450 struct swapdev *sdp = vnx->vx_sdp; 1451 int s, resid, error; 1452 KASSERT(&vbp->vb_buf.b_work == wk); 1453 UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); 1454 1455 UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p", 1456 vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); 1457 UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", 1458 vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); 1459 1460 /* 1461 * protect vbp at splbio and update. 1462 */ 1463 1464 s = splbio(); 1465 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 1466 pbp->b_resid -= resid; 1467 vnx->vx_pending--; 1468 1469 if (vbp->vb_buf.b_error != 0) { 1470 /* pass error upward */ 1471 error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; 1472 UVMHIST_LOG(pdhist, " got error=%d !", error, 0, 0, 0); 1473 vnx->vx_error = error; 1474 } 1475 1476 /* 1477 * kill vbp structure 1478 */ 1479 buf_destroy(&vbp->vb_buf); 1480 pool_put(&vndbuf_pool, vbp); 1481 1482 /* 1483 * wrap up this transaction if it has run to completion or, in 1484 * case of an error, when all auxiliary buffers have returned. 1485 */ 1486 if (vnx->vx_error != 0) { 1487 /* pass error upward */ 1488 error = vnx->vx_error; 1489 if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { 1490 pbp->b_error = error; 1491 biodone(pbp); 1492 pool_put(&vndxfer_pool, vnx); 1493 } 1494 } else if (pbp->b_resid == 0) { 1495 KASSERT(vnx->vx_pending == 0); 1496 if ((vnx->vx_flags & VX_BUSY) == 0) { 1497 UVMHIST_LOG(pdhist, " iodone error=%d !", 1498 pbp, vnx->vx_error, 0, 0); 1499 biodone(pbp); 1500 pool_put(&vndxfer_pool, vnx); 1501 } 1502 } 1503 1504 /* 1505 * done! start next swapdev I/O if one is pending 1506 */ 1507 sdp->swd_active--; 1508 sw_reg_start(sdp); 1509 splx(s); 1510 } 1511 1512 1513 /* 1514 * uvm_swap_alloc: allocate space on swap 1515 * 1516 * => allocation is done "round robin" down the priority list, as we 1517 * allocate in a priority we "rotate" the circle queue. 1518 * => space can be freed with uvm_swap_free 1519 * => we return the page slot number in /dev/drum (0 == invalid slot) 1520 * => we lock uvm_swap_data_lock 1521 * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM 1522 */ 1523 int 1524 uvm_swap_alloc(int *nslots /* IN/OUT */, bool lessok) 1525 { 1526 struct swapdev *sdp; 1527 struct swappri *spp; 1528 UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); 1529 1530 /* 1531 * no swap devices configured yet? definite failure. 1532 */ 1533 if (uvmexp.nswapdev < 1) 1534 return 0; 1535 1536 /* 1537 * lock data lock, convert slots into blocks, and enter loop 1538 */ 1539 mutex_enter(&uvm_swap_data_lock); 1540 1541 ReTry: /* XXXMRG */ 1542 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 1543 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 1544 uint64_t result; 1545 1546 /* if it's not enabled, then we can't swap from it */ 1547 if ((sdp->swd_flags & SWF_ENABLE) == 0) 1548 continue; 1549 if (sdp->swd_npginuse + *nslots > sdp->swd_npages) 1550 continue; 1551 result = blist_alloc(sdp->swd_blist, *nslots); 1552 if (result == BLIST_NONE) { 1553 continue; 1554 } 1555 KASSERT(result < sdp->swd_drumsize); 1556 1557 /* 1558 * successful allocation! now rotate the circleq. 1559 */ 1560 CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); 1561 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 1562 sdp->swd_npginuse += *nslots; 1563 uvmexp.swpginuse += *nslots; 1564 mutex_exit(&uvm_swap_data_lock); 1565 /* done! return drum slot number */ 1566 UVMHIST_LOG(pdhist, 1567 "success! returning %d slots starting at %d", 1568 *nslots, result + sdp->swd_drumoffset, 0, 0); 1569 return (result + sdp->swd_drumoffset); 1570 } 1571 } 1572 1573 /* XXXMRG: BEGIN HACK */ 1574 if (*nslots > 1 && lessok) { 1575 *nslots = 1; 1576 /* XXXMRG: ugh! blist should support this for us */ 1577 goto ReTry; 1578 } 1579 /* XXXMRG: END HACK */ 1580 1581 mutex_exit(&uvm_swap_data_lock); 1582 return 0; 1583 } 1584 1585 /* 1586 * uvm_swapisfull: return true if most of available swap is allocated 1587 * and in use. we don't count some small portion as it may be inaccessible 1588 * to us at any given moment, for example if there is lock contention or if 1589 * pages are busy. 1590 */ 1591 bool 1592 uvm_swapisfull(void) 1593 { 1594 int swpgonly; 1595 bool rv; 1596 1597 mutex_enter(&uvm_swap_data_lock); 1598 KASSERT(uvmexp.swpgonly <= uvmexp.swpages); 1599 swpgonly = (int)((uint64_t)uvmexp.swpgonly * 100 / 1600 uvm_swapisfull_factor); 1601 rv = (swpgonly >= uvmexp.swpgavail); 1602 mutex_exit(&uvm_swap_data_lock); 1603 1604 return (rv); 1605 } 1606 1607 /* 1608 * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors 1609 * 1610 * => we lock uvm_swap_data_lock 1611 */ 1612 void 1613 uvm_swap_markbad(int startslot, int nslots) 1614 { 1615 struct swapdev *sdp; 1616 UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); 1617 1618 mutex_enter(&uvm_swap_data_lock); 1619 sdp = swapdrum_getsdp(startslot); 1620 KASSERT(sdp != NULL); 1621 1622 /* 1623 * we just keep track of how many pages have been marked bad 1624 * in this device, to make everything add up in swap_off(). 1625 * we assume here that the range of slots will all be within 1626 * one swap device. 1627 */ 1628 1629 KASSERT(uvmexp.swpgonly >= nslots); 1630 uvmexp.swpgonly -= nslots; 1631 sdp->swd_npgbad += nslots; 1632 UVMHIST_LOG(pdhist, "now %d bad", sdp->swd_npgbad, 0,0,0); 1633 mutex_exit(&uvm_swap_data_lock); 1634 } 1635 1636 /* 1637 * uvm_swap_free: free swap slots 1638 * 1639 * => this can be all or part of an allocation made by uvm_swap_alloc 1640 * => we lock uvm_swap_data_lock 1641 */ 1642 void 1643 uvm_swap_free(int startslot, int nslots) 1644 { 1645 struct swapdev *sdp; 1646 UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); 1647 1648 UVMHIST_LOG(pdhist, "freeing %d slots starting at %d", nslots, 1649 startslot, 0, 0); 1650 1651 /* 1652 * ignore attempts to free the "bad" slot. 1653 */ 1654 1655 if (startslot == SWSLOT_BAD) { 1656 return; 1657 } 1658 1659 /* 1660 * convert drum slot offset back to sdp, free the blocks 1661 * in the extent, and return. must hold pri lock to do 1662 * lookup and access the extent. 1663 */ 1664 1665 mutex_enter(&uvm_swap_data_lock); 1666 sdp = swapdrum_getsdp(startslot); 1667 KASSERT(uvmexp.nswapdev >= 1); 1668 KASSERT(sdp != NULL); 1669 KASSERT(sdp->swd_npginuse >= nslots); 1670 blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); 1671 sdp->swd_npginuse -= nslots; 1672 uvmexp.swpginuse -= nslots; 1673 mutex_exit(&uvm_swap_data_lock); 1674 } 1675 1676 /* 1677 * uvm_swap_put: put any number of pages into a contig place on swap 1678 * 1679 * => can be sync or async 1680 */ 1681 1682 int 1683 uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) 1684 { 1685 int error; 1686 1687 error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | 1688 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1689 return error; 1690 } 1691 1692 /* 1693 * uvm_swap_get: get a single page from swap 1694 * 1695 * => usually a sync op (from fault) 1696 */ 1697 1698 int 1699 uvm_swap_get(struct vm_page *page, int swslot, int flags) 1700 { 1701 int error; 1702 1703 uvmexp.nswget++; 1704 KASSERT(flags & PGO_SYNCIO); 1705 if (swslot == SWSLOT_BAD) { 1706 return EIO; 1707 } 1708 1709 error = uvm_swap_io(&page, swslot, 1, B_READ | 1710 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1711 if (error == 0) { 1712 1713 /* 1714 * this page is no longer only in swap. 1715 */ 1716 1717 mutex_enter(&uvm_swap_data_lock); 1718 KASSERT(uvmexp.swpgonly > 0); 1719 uvmexp.swpgonly--; 1720 mutex_exit(&uvm_swap_data_lock); 1721 } 1722 return error; 1723 } 1724 1725 /* 1726 * uvm_swap_io: do an i/o operation to swap 1727 */ 1728 1729 static int 1730 uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) 1731 { 1732 daddr_t startblk; 1733 struct buf *bp; 1734 vaddr_t kva; 1735 int error, mapinflags; 1736 bool write, async; 1737 UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); 1738 1739 UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d", 1740 startslot, npages, flags, 0); 1741 1742 write = (flags & B_READ) == 0; 1743 async = (flags & B_ASYNC) != 0; 1744 1745 /* 1746 * allocate a buf for the i/o. 1747 */ 1748 1749 KASSERT(curlwp != uvm.pagedaemon_lwp || (write && async)); 1750 bp = getiobuf(swapdev_vp, curlwp != uvm.pagedaemon_lwp); 1751 if (bp == NULL) { 1752 uvm_aio_aiodone_pages(pps, npages, true, ENOMEM); 1753 return ENOMEM; 1754 } 1755 1756 /* 1757 * convert starting drum slot to block number 1758 */ 1759 1760 startblk = btodb((uint64_t)startslot << PAGE_SHIFT); 1761 1762 /* 1763 * first, map the pages into the kernel. 1764 */ 1765 1766 mapinflags = !write ? 1767 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : 1768 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; 1769 kva = uvm_pagermapin(pps, npages, mapinflags); 1770 1771 /* 1772 * fill in the bp/sbp. we currently route our i/o through 1773 * /dev/drum's vnode [swapdev_vp]. 1774 */ 1775 1776 bp->b_cflags = BC_BUSY | BC_NOCACHE; 1777 bp->b_flags = (flags & (B_READ|B_ASYNC)); 1778 bp->b_proc = &proc0; /* XXX */ 1779 bp->b_vnbufs.le_next = NOLIST; 1780 bp->b_data = (void *)kva; 1781 bp->b_blkno = startblk; 1782 bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; 1783 1784 /* 1785 * bump v_numoutput (counter of number of active outputs). 1786 */ 1787 1788 if (write) { 1789 mutex_enter(&swapdev_vp->v_interlock); 1790 swapdev_vp->v_numoutput++; 1791 mutex_exit(&swapdev_vp->v_interlock); 1792 } 1793 1794 /* 1795 * for async ops we must set up the iodone handler. 1796 */ 1797 1798 if (async) { 1799 bp->b_iodone = uvm_aio_biodone; 1800 UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); 1801 if (curlwp == uvm.pagedaemon_lwp) 1802 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1803 else 1804 BIO_SETPRIO(bp, BPRIO_TIMELIMITED); 1805 } else { 1806 bp->b_iodone = NULL; 1807 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1808 } 1809 UVMHIST_LOG(pdhist, 1810 "about to start io: data = %p blkno = 0x%x, bcount = %ld", 1811 bp->b_data, bp->b_blkno, bp->b_bcount, 0); 1812 1813 /* 1814 * now we start the I/O, and if async, return. 1815 */ 1816 1817 VOP_STRATEGY(swapdev_vp, bp); 1818 if (async) 1819 return 0; 1820 1821 /* 1822 * must be sync i/o. wait for it to finish 1823 */ 1824 1825 error = biowait(bp); 1826 1827 /* 1828 * kill the pager mapping 1829 */ 1830 1831 uvm_pagermapout(kva, npages); 1832 1833 /* 1834 * now dispose of the buf and we're done. 1835 */ 1836 1837 if (write) { 1838 mutex_enter(&swapdev_vp->v_interlock); 1839 vwakeup(bp); 1840 mutex_exit(&swapdev_vp->v_interlock); 1841 } 1842 putiobuf(bp); 1843 UVMHIST_LOG(pdhist, "<- done (sync) error=%d", error, 0, 0, 0); 1844 1845 return (error); 1846 } 1847