1 /* $NetBSD: uvm_swap.c,v 1.163 2013/05/07 15:49:09 riastradh 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 1.163 2013/05/07 15:49:09 riastradh 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/vnode.h> 50 #include <sys/file.h> 51 #include <sys/vmem.h> 52 #include <sys/blist.h> 53 #include <sys/mount.h> 54 #include <sys/pool.h> 55 #include <sys/kmem.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() 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 static vmem_t *swapmap; /* controls the mapping of /dev/drum */ 212 213 /* list of all active swap devices [by priority] */ 214 LIST_HEAD(swap_priority, swappri); 215 static struct swap_priority swap_priority; 216 217 /* locks */ 218 static krwlock_t swap_syscall_lock; 219 220 /* workqueue and use counter for swap to regular files */ 221 static int sw_reg_count = 0; 222 static struct workqueue *sw_reg_workqueue; 223 224 /* tuneables */ 225 u_int uvm_swapisfull_factor = 99; 226 227 /* 228 * prototypes 229 */ 230 static struct swapdev *swapdrum_getsdp(int); 231 232 static struct swapdev *swaplist_find(struct vnode *, bool); 233 static void swaplist_insert(struct swapdev *, 234 struct swappri *, int); 235 static void swaplist_trim(void); 236 237 static int swap_on(struct lwp *, struct swapdev *); 238 static int swap_off(struct lwp *, struct swapdev *); 239 240 static void uvm_swap_stats(int, struct swapent *, int, register_t *); 241 242 static void sw_reg_strategy(struct swapdev *, struct buf *, int); 243 static void sw_reg_biodone(struct buf *); 244 static void sw_reg_iodone(struct work *wk, void *dummy); 245 static void sw_reg_start(struct swapdev *); 246 247 static int uvm_swap_io(struct vm_page **, int, int, int); 248 249 /* 250 * uvm_swap_init: init the swap system data structures and locks 251 * 252 * => called at boot time from init_main.c after the filesystems 253 * are brought up (which happens after uvm_init()) 254 */ 255 void 256 uvm_swap_init(void) 257 { 258 UVMHIST_FUNC("uvm_swap_init"); 259 260 UVMHIST_CALLED(pdhist); 261 /* 262 * first, init the swap list, its counter, and its lock. 263 * then get a handle on the vnode for /dev/drum by using 264 * the its dev_t number ("swapdev", from MD conf.c). 265 */ 266 267 LIST_INIT(&swap_priority); 268 uvmexp.nswapdev = 0; 269 rw_init(&swap_syscall_lock); 270 mutex_init(&uvm_swap_data_lock, MUTEX_DEFAULT, IPL_NONE); 271 272 if (bdevvp(swapdev, &swapdev_vp)) 273 panic("%s: can't get vnode for swap device", __func__); 274 if (vn_lock(swapdev_vp, LK_EXCLUSIVE | LK_RETRY)) 275 panic("%s: can't lock swap device", __func__); 276 if (VOP_OPEN(swapdev_vp, FREAD | FWRITE, NOCRED)) 277 panic("%s: can't open swap device", __func__); 278 VOP_UNLOCK(swapdev_vp); 279 280 /* 281 * create swap block resource map to map /dev/drum. the range 282 * from 1 to INT_MAX allows 2 gigablocks of swap space. note 283 * that block 0 is reserved (used to indicate an allocation 284 * failure, or no allocation). 285 */ 286 swapmap = vmem_create("swapmap", 1, INT_MAX - 1, 1, NULL, NULL, NULL, 0, 287 VM_NOSLEEP, IPL_NONE); 288 if (swapmap == 0) { 289 panic("%s: vmem_create failed", __func__); 290 } 291 292 pool_init(&vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", 293 NULL, IPL_BIO); 294 pool_init(&vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", 295 NULL, IPL_BIO); 296 297 UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); 298 } 299 300 /* 301 * swaplist functions: functions that operate on the list of swap 302 * devices on the system. 303 */ 304 305 /* 306 * swaplist_insert: insert swap device "sdp" into the global list 307 * 308 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 309 * => caller must provide a newly allocated swappri structure (we will 310 * FREE it if we don't need it... this it to prevent allocation 311 * blocking here while adding swap) 312 */ 313 static void 314 swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) 315 { 316 struct swappri *spp, *pspp; 317 UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); 318 319 /* 320 * find entry at or after which to insert the new device. 321 */ 322 pspp = NULL; 323 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 324 if (priority <= spp->spi_priority) 325 break; 326 pspp = spp; 327 } 328 329 /* 330 * new priority? 331 */ 332 if (spp == NULL || spp->spi_priority != priority) { 333 spp = newspp; /* use newspp! */ 334 UVMHIST_LOG(pdhist, "created new swappri = %d", 335 priority, 0, 0, 0); 336 337 spp->spi_priority = priority; 338 CIRCLEQ_INIT(&spp->spi_swapdev); 339 340 if (pspp) 341 LIST_INSERT_AFTER(pspp, spp, spi_swappri); 342 else 343 LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); 344 } else { 345 /* we don't need a new priority structure, free it */ 346 kmem_free(newspp, sizeof(*newspp)); 347 } 348 349 /* 350 * priority found (or created). now insert on the priority's 351 * circleq list and bump the total number of swapdevs. 352 */ 353 sdp->swd_priority = priority; 354 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 355 uvmexp.nswapdev++; 356 } 357 358 /* 359 * swaplist_find: find and optionally remove a swap device from the 360 * global list. 361 * 362 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 363 * => we return the swapdev we found (and removed) 364 */ 365 static struct swapdev * 366 swaplist_find(struct vnode *vp, bool remove) 367 { 368 struct swapdev *sdp; 369 struct swappri *spp; 370 371 /* 372 * search the lists for the requested vp 373 */ 374 375 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 376 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 377 if (sdp->swd_vp == vp) { 378 if (remove) { 379 CIRCLEQ_REMOVE(&spp->spi_swapdev, 380 sdp, swd_next); 381 uvmexp.nswapdev--; 382 } 383 return(sdp); 384 } 385 } 386 } 387 return (NULL); 388 } 389 390 /* 391 * swaplist_trim: scan priority list for empty priority entries and kill 392 * them. 393 * 394 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 395 */ 396 static void 397 swaplist_trim(void) 398 { 399 struct swappri *spp, *nextspp; 400 401 LIST_FOREACH_SAFE(spp, &swap_priority, spi_swappri, nextspp) { 402 if (CIRCLEQ_FIRST(&spp->spi_swapdev) != 403 (void *)&spp->spi_swapdev) 404 continue; 405 LIST_REMOVE(spp, spi_swappri); 406 kmem_free(spp, sizeof(*spp)); 407 } 408 } 409 410 /* 411 * swapdrum_getsdp: given a page offset in /dev/drum, convert it back 412 * to the "swapdev" that maps that section of the drum. 413 * 414 * => each swapdev takes one big contig chunk of the drum 415 * => caller must hold uvm_swap_data_lock 416 */ 417 static struct swapdev * 418 swapdrum_getsdp(int pgno) 419 { 420 struct swapdev *sdp; 421 struct swappri *spp; 422 423 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 424 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 425 if (sdp->swd_flags & SWF_FAKE) 426 continue; 427 if (pgno >= sdp->swd_drumoffset && 428 pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { 429 return sdp; 430 } 431 } 432 } 433 return NULL; 434 } 435 436 437 /* 438 * sys_swapctl: main entry point for swapctl(2) system call 439 * [with two helper functions: swap_on and swap_off] 440 */ 441 int 442 sys_swapctl(struct lwp *l, const struct sys_swapctl_args *uap, register_t *retval) 443 { 444 /* { 445 syscallarg(int) cmd; 446 syscallarg(void *) arg; 447 syscallarg(int) misc; 448 } */ 449 struct vnode *vp; 450 struct nameidata nd; 451 struct swappri *spp; 452 struct swapdev *sdp; 453 struct swapent *sep; 454 #define SWAP_PATH_MAX (PATH_MAX + 1) 455 char *userpath; 456 size_t len = 0; 457 int error, misc; 458 int priority; 459 UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); 460 461 /* 462 * we handle the non-priv NSWAP and STATS request first. 463 * 464 * SWAP_NSWAP: return number of config'd swap devices 465 * [can also be obtained with uvmexp sysctl] 466 */ 467 if (SCARG(uap, cmd) == SWAP_NSWAP) { 468 const int nswapdev = uvmexp.nswapdev; 469 UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d", nswapdev, 0, 0, 0); 470 *retval = nswapdev; 471 return 0; 472 } 473 474 misc = SCARG(uap, misc); 475 userpath = kmem_alloc(SWAP_PATH_MAX, KM_SLEEP); 476 477 /* 478 * ensure serialized syscall access by grabbing the swap_syscall_lock 479 */ 480 rw_enter(&swap_syscall_lock, RW_WRITER); 481 482 /* 483 * SWAP_STATS: get stats on current # of configured swap devs 484 * 485 * note that the swap_priority list can't change as long 486 * as we are holding the swap_syscall_lock. we don't want 487 * to grab the uvm_swap_data_lock because we may fault&sleep during 488 * copyout() and we don't want to be holding that lock then! 489 */ 490 if (SCARG(uap, cmd) == SWAP_STATS 491 #if defined(COMPAT_50) 492 || SCARG(uap, cmd) == SWAP_STATS50 493 #endif 494 #if defined(COMPAT_13) 495 || SCARG(uap, cmd) == SWAP_STATS13 496 #endif 497 ) { 498 if ((size_t)misc > (size_t)uvmexp.nswapdev) 499 misc = uvmexp.nswapdev; 500 501 if (misc == 0) { 502 error = EINVAL; 503 goto out; 504 } 505 KASSERT(misc > 0); 506 #if defined(COMPAT_13) 507 if (SCARG(uap, cmd) == SWAP_STATS13) 508 len = sizeof(struct swapent13) * misc; 509 else 510 #endif 511 #if defined(COMPAT_50) 512 if (SCARG(uap, cmd) == SWAP_STATS50) 513 len = sizeof(struct swapent50) * misc; 514 else 515 #endif 516 len = sizeof(struct swapent) * misc; 517 sep = (struct swapent *)kmem_alloc(len, KM_SLEEP); 518 519 uvm_swap_stats(SCARG(uap, cmd), sep, misc, retval); 520 error = copyout(sep, SCARG(uap, arg), len); 521 522 kmem_free(sep, len); 523 UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); 524 goto out; 525 } 526 if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { 527 dev_t *devp = (dev_t *)SCARG(uap, arg); 528 529 error = copyout(&dumpdev, devp, sizeof(dumpdev)); 530 goto out; 531 } 532 533 /* 534 * all other requests require superuser privs. verify. 535 */ 536 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SWAPCTL, 537 0, NULL, NULL, NULL))) 538 goto out; 539 540 if (SCARG(uap, cmd) == SWAP_DUMPOFF) { 541 /* drop the current dump device */ 542 dumpdev = NODEV; 543 dumpcdev = NODEV; 544 cpu_dumpconf(); 545 goto out; 546 } 547 548 /* 549 * at this point we expect a path name in arg. we will 550 * use namei() to gain a vnode reference (vref), and lock 551 * the vnode (VOP_LOCK). 552 * 553 * XXX: a NULL arg means use the root vnode pointer (e.g. for 554 * miniroot) 555 */ 556 if (SCARG(uap, arg) == NULL) { 557 vp = rootvp; /* miniroot */ 558 vref(vp); 559 if (vn_lock(vp, LK_EXCLUSIVE)) { 560 vrele(vp); 561 error = EBUSY; 562 goto out; 563 } 564 if (SCARG(uap, cmd) == SWAP_ON && 565 copystr("miniroot", userpath, SWAP_PATH_MAX, &len)) 566 panic("swapctl: miniroot copy failed"); 567 KASSERT(len > 0); 568 } else { 569 struct pathbuf *pb; 570 571 /* 572 * This used to allow copying in one extra byte 573 * (SWAP_PATH_MAX instead of PATH_MAX) for SWAP_ON. 574 * This was completely pointless because if anyone 575 * used that extra byte namei would fail with 576 * ENAMETOOLONG anyway, so I've removed the excess 577 * logic. - dholland 20100215 578 */ 579 580 error = pathbuf_copyin(SCARG(uap, arg), &pb); 581 if (error) { 582 goto out; 583 } 584 if (SCARG(uap, cmd) == SWAP_ON) { 585 /* get a copy of the string */ 586 pathbuf_copystring(pb, userpath, SWAP_PATH_MAX); 587 len = strlen(userpath) + 1; 588 } 589 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); 590 if ((error = namei(&nd))) { 591 pathbuf_destroy(pb); 592 goto out; 593 } 594 vp = nd.ni_vp; 595 pathbuf_destroy(pb); 596 } 597 /* note: "vp" is referenced and locked */ 598 599 error = 0; /* assume no error */ 600 switch(SCARG(uap, cmd)) { 601 602 case SWAP_DUMPDEV: 603 if (vp->v_type != VBLK) { 604 error = ENOTBLK; 605 break; 606 } 607 if (bdevsw_lookup(vp->v_rdev)) { 608 dumpdev = vp->v_rdev; 609 dumpcdev = devsw_blk2chr(dumpdev); 610 } else 611 dumpdev = NODEV; 612 cpu_dumpconf(); 613 break; 614 615 case SWAP_CTL: 616 /* 617 * get new priority, remove old entry (if any) and then 618 * reinsert it in the correct place. finally, prune out 619 * any empty priority structures. 620 */ 621 priority = SCARG(uap, misc); 622 spp = kmem_alloc(sizeof(*spp), KM_SLEEP); 623 mutex_enter(&uvm_swap_data_lock); 624 if ((sdp = swaplist_find(vp, true)) == NULL) { 625 error = ENOENT; 626 } else { 627 swaplist_insert(sdp, spp, priority); 628 swaplist_trim(); 629 } 630 mutex_exit(&uvm_swap_data_lock); 631 if (error) 632 kmem_free(spp, sizeof(*spp)); 633 break; 634 635 case SWAP_ON: 636 637 /* 638 * check for duplicates. if none found, then insert a 639 * dummy entry on the list to prevent someone else from 640 * trying to enable this device while we are working on 641 * it. 642 */ 643 644 priority = SCARG(uap, misc); 645 sdp = kmem_zalloc(sizeof(*sdp), KM_SLEEP); 646 spp = kmem_alloc(sizeof(*spp), KM_SLEEP); 647 sdp->swd_flags = SWF_FAKE; 648 sdp->swd_vp = vp; 649 sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; 650 bufq_alloc(&sdp->swd_tab, "disksort", BUFQ_SORT_RAWBLOCK); 651 mutex_enter(&uvm_swap_data_lock); 652 if (swaplist_find(vp, false) != NULL) { 653 error = EBUSY; 654 mutex_exit(&uvm_swap_data_lock); 655 bufq_free(sdp->swd_tab); 656 kmem_free(sdp, sizeof(*sdp)); 657 kmem_free(spp, sizeof(*spp)); 658 break; 659 } 660 swaplist_insert(sdp, spp, priority); 661 mutex_exit(&uvm_swap_data_lock); 662 663 KASSERT(len > 0); 664 sdp->swd_pathlen = len; 665 sdp->swd_path = kmem_alloc(len, KM_SLEEP); 666 if (copystr(userpath, sdp->swd_path, len, 0) != 0) 667 panic("swapctl: copystr"); 668 669 /* 670 * we've now got a FAKE placeholder in the swap list. 671 * now attempt to enable swap on it. if we fail, undo 672 * what we've done and kill the fake entry we just inserted. 673 * if swap_on is a success, it will clear the SWF_FAKE flag 674 */ 675 676 if ((error = swap_on(l, sdp)) != 0) { 677 mutex_enter(&uvm_swap_data_lock); 678 (void) swaplist_find(vp, true); /* kill fake entry */ 679 swaplist_trim(); 680 mutex_exit(&uvm_swap_data_lock); 681 bufq_free(sdp->swd_tab); 682 kmem_free(sdp->swd_path, sdp->swd_pathlen); 683 kmem_free(sdp, sizeof(*sdp)); 684 break; 685 } 686 break; 687 688 case SWAP_OFF: 689 mutex_enter(&uvm_swap_data_lock); 690 if ((sdp = swaplist_find(vp, false)) == NULL) { 691 mutex_exit(&uvm_swap_data_lock); 692 error = ENXIO; 693 break; 694 } 695 696 /* 697 * If a device isn't in use or enabled, we 698 * can't stop swapping from it (again). 699 */ 700 if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { 701 mutex_exit(&uvm_swap_data_lock); 702 error = EBUSY; 703 break; 704 } 705 706 /* 707 * do the real work. 708 */ 709 error = swap_off(l, sdp); 710 break; 711 712 default: 713 error = EINVAL; 714 } 715 716 /* 717 * done! release the ref gained by namei() and unlock. 718 */ 719 vput(vp); 720 out: 721 rw_exit(&swap_syscall_lock); 722 kmem_free(userpath, SWAP_PATH_MAX); 723 724 UVMHIST_LOG(pdhist, "<- done! error=%d", error, 0, 0, 0); 725 return (error); 726 } 727 728 /* 729 * uvm_swap_stats: implements swapctl(SWAP_STATS). The function is kept 730 * away from sys_swapctl() in order to allow COMPAT_* swapctl() 731 * emulation to use it directly without going through sys_swapctl(). 732 * The problem with using sys_swapctl() there is that it involves 733 * copying the swapent array to the stackgap, and this array's size 734 * is not known at build time. Hence it would not be possible to 735 * ensure it would fit in the stackgap in any case. 736 */ 737 static void 738 uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) 739 { 740 struct swappri *spp; 741 struct swapdev *sdp; 742 int count = 0; 743 744 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 745 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 746 int inuse; 747 748 if (sec-- <= 0) 749 break; 750 751 /* 752 * backwards compatibility for system call. 753 * For NetBSD 1.3 and 5.0, we have to use 754 * the 32 bit dev_t. For 5.0 and -current 755 * we have to add the path. 756 */ 757 inuse = btodb((uint64_t)sdp->swd_npginuse << 758 PAGE_SHIFT); 759 760 #if defined(COMPAT_13) || defined(COMPAT_50) 761 if (cmd == SWAP_STATS) { 762 #endif 763 sep->se_dev = sdp->swd_dev; 764 sep->se_flags = sdp->swd_flags; 765 sep->se_nblks = sdp->swd_nblks; 766 sep->se_inuse = inuse; 767 sep->se_priority = sdp->swd_priority; 768 KASSERT(sdp->swd_pathlen < 769 sizeof(sep->se_path)); 770 strcpy(sep->se_path, sdp->swd_path); 771 sep++; 772 #if defined(COMPAT_13) 773 } else if (cmd == SWAP_STATS13) { 774 struct swapent13 *sep13 = 775 (struct swapent13 *)sep; 776 777 sep13->se13_dev = sdp->swd_dev; 778 sep13->se13_flags = sdp->swd_flags; 779 sep13->se13_nblks = sdp->swd_nblks; 780 sep13->se13_inuse = inuse; 781 sep13->se13_priority = sdp->swd_priority; 782 sep = (struct swapent *)(sep13 + 1); 783 #endif 784 #if defined(COMPAT_50) 785 } else if (cmd == SWAP_STATS50) { 786 struct swapent50 *sep50 = 787 (struct swapent50 *)sep; 788 789 sep50->se50_dev = sdp->swd_dev; 790 sep50->se50_flags = sdp->swd_flags; 791 sep50->se50_nblks = sdp->swd_nblks; 792 sep50->se50_inuse = inuse; 793 sep50->se50_priority = sdp->swd_priority; 794 KASSERT(sdp->swd_pathlen < 795 sizeof(sep50->se50_path)); 796 strcpy(sep50->se50_path, sdp->swd_path); 797 sep = (struct swapent *)(sep50 + 1); 798 #endif 799 #if defined(COMPAT_13) || defined(COMPAT_50) 800 } 801 #endif 802 count++; 803 } 804 } 805 *retval = count; 806 } 807 808 /* 809 * swap_on: attempt to enable a swapdev for swapping. note that the 810 * swapdev is already on the global list, but disabled (marked 811 * SWF_FAKE). 812 * 813 * => we avoid the start of the disk (to protect disk labels) 814 * => we also avoid the miniroot, if we are swapping to root. 815 * => caller should leave uvm_swap_data_lock unlocked, we may lock it 816 * if needed. 817 */ 818 static int 819 swap_on(struct lwp *l, struct swapdev *sdp) 820 { 821 struct vnode *vp; 822 int error, npages, nblocks, size; 823 long addr; 824 vmem_addr_t result; 825 struct vattr va; 826 dev_t dev; 827 UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); 828 829 /* 830 * we want to enable swapping on sdp. the swd_vp contains 831 * the vnode we want (locked and ref'd), and the swd_dev 832 * contains the dev_t of the file, if it a block device. 833 */ 834 835 vp = sdp->swd_vp; 836 dev = sdp->swd_dev; 837 838 /* 839 * open the swap file (mostly useful for block device files to 840 * let device driver know what is up). 841 * 842 * we skip the open/close for root on swap because the root 843 * has already been opened when root was mounted (mountroot). 844 */ 845 if (vp != rootvp) { 846 if ((error = VOP_OPEN(vp, FREAD|FWRITE, l->l_cred))) 847 return (error); 848 } 849 850 /* XXX this only works for block devices */ 851 UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d", dev, major(dev), 0,0); 852 853 /* 854 * we now need to determine the size of the swap area. for 855 * block specials we can call the d_psize function. 856 * for normal files, we must stat [get attrs]. 857 * 858 * we put the result in nblks. 859 * for normal files, we also want the filesystem block size 860 * (which we get with statfs). 861 */ 862 switch (vp->v_type) { 863 case VBLK: 864 if ((nblocks = bdev_size(dev)) == -1) { 865 error = ENXIO; 866 goto bad; 867 } 868 break; 869 870 case VREG: 871 if ((error = VOP_GETATTR(vp, &va, l->l_cred))) 872 goto bad; 873 nblocks = (int)btodb(va.va_size); 874 sdp->swd_bsize = 1 << vp->v_mount->mnt_fs_bshift; 875 /* 876 * limit the max # of outstanding I/O requests we issue 877 * at any one time. take it easy on NFS servers. 878 */ 879 if (vp->v_tag == VT_NFS) 880 sdp->swd_maxactive = 2; /* XXX */ 881 else 882 sdp->swd_maxactive = 8; /* XXX */ 883 break; 884 885 default: 886 error = ENXIO; 887 goto bad; 888 } 889 890 /* 891 * save nblocks in a safe place and convert to pages. 892 */ 893 894 sdp->swd_nblks = nblocks; 895 npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; 896 897 /* 898 * for block special files, we want to make sure that leave 899 * the disklabel and bootblocks alone, so we arrange to skip 900 * over them (arbitrarily choosing to skip PAGE_SIZE bytes). 901 * note that because of this the "size" can be less than the 902 * actual number of blocks on the device. 903 */ 904 if (vp->v_type == VBLK) { 905 /* we use pages 1 to (size - 1) [inclusive] */ 906 size = npages - 1; 907 addr = 1; 908 } else { 909 /* we use pages 0 to (size - 1) [inclusive] */ 910 size = npages; 911 addr = 0; 912 } 913 914 /* 915 * make sure we have enough blocks for a reasonable sized swap 916 * area. we want at least one page. 917 */ 918 919 if (size < 1) { 920 UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); 921 error = EINVAL; 922 goto bad; 923 } 924 925 UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld\n", dev, size, addr, 0); 926 927 /* 928 * now we need to allocate an extent to manage this swap device 929 */ 930 931 sdp->swd_blist = blist_create(npages); 932 /* mark all expect the `saved' region free. */ 933 blist_free(sdp->swd_blist, addr, size); 934 935 /* 936 * if the vnode we are swapping to is the root vnode 937 * (i.e. we are swapping to the miniroot) then we want 938 * to make sure we don't overwrite it. do a statfs to 939 * find its size and skip over it. 940 */ 941 if (vp == rootvp) { 942 struct mount *mp; 943 struct statvfs *sp; 944 int rootblocks, rootpages; 945 946 mp = rootvnode->v_mount; 947 sp = &mp->mnt_stat; 948 rootblocks = sp->f_blocks * btodb(sp->f_frsize); 949 /* 950 * XXX: sp->f_blocks isn't the total number of 951 * blocks in the filesystem, it's the number of 952 * data blocks. so, our rootblocks almost 953 * definitely underestimates the total size 954 * of the filesystem - how badly depends on the 955 * details of the filesystem type. there isn't 956 * an obvious way to deal with this cleanly 957 * and perfectly, so for now we just pad our 958 * rootblocks estimate with an extra 5 percent. 959 */ 960 rootblocks += (rootblocks >> 5) + 961 (rootblocks >> 6) + 962 (rootblocks >> 7); 963 rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; 964 if (rootpages > size) 965 panic("swap_on: miniroot larger than swap?"); 966 967 if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { 968 panic("swap_on: unable to preserve miniroot"); 969 } 970 971 size -= rootpages; 972 printf("Preserved %d pages of miniroot ", rootpages); 973 printf("leaving %d pages of swap\n", size); 974 } 975 976 /* 977 * add a ref to vp to reflect usage as a swap device. 978 */ 979 vref(vp); 980 981 /* 982 * now add the new swapdev to the drum and enable. 983 */ 984 error = vmem_alloc(swapmap, npages, VM_BESTFIT | VM_SLEEP, &result); 985 if (error != 0) 986 panic("swapdrum_add"); 987 /* 988 * If this is the first regular swap create the workqueue. 989 * => Protected by swap_syscall_lock. 990 */ 991 if (vp->v_type != VBLK) { 992 if (sw_reg_count++ == 0) { 993 KASSERT(sw_reg_workqueue == NULL); 994 if (workqueue_create(&sw_reg_workqueue, "swapiod", 995 sw_reg_iodone, NULL, PRIBIO, IPL_BIO, 0) != 0) 996 panic("%s: workqueue_create failed", __func__); 997 } 998 } 999 1000 sdp->swd_drumoffset = (int)result; 1001 sdp->swd_drumsize = npages; 1002 sdp->swd_npages = size; 1003 mutex_enter(&uvm_swap_data_lock); 1004 sdp->swd_flags &= ~SWF_FAKE; /* going live */ 1005 sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); 1006 uvmexp.swpages += size; 1007 uvmexp.swpgavail += size; 1008 mutex_exit(&uvm_swap_data_lock); 1009 return (0); 1010 1011 /* 1012 * failure: clean up and return error. 1013 */ 1014 1015 bad: 1016 if (sdp->swd_blist) { 1017 blist_destroy(sdp->swd_blist); 1018 } 1019 if (vp != rootvp) { 1020 (void)VOP_CLOSE(vp, FREAD|FWRITE, l->l_cred); 1021 } 1022 return (error); 1023 } 1024 1025 /* 1026 * swap_off: stop swapping on swapdev 1027 * 1028 * => swap data should be locked, we will unlock. 1029 */ 1030 static int 1031 swap_off(struct lwp *l, struct swapdev *sdp) 1032 { 1033 int npages = sdp->swd_npages; 1034 int error = 0; 1035 1036 UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); 1037 UVMHIST_LOG(pdhist, " dev=%x, npages=%d", sdp->swd_dev,npages,0,0); 1038 1039 /* disable the swap area being removed */ 1040 sdp->swd_flags &= ~SWF_ENABLE; 1041 uvmexp.swpgavail -= npages; 1042 mutex_exit(&uvm_swap_data_lock); 1043 1044 /* 1045 * the idea is to find all the pages that are paged out to this 1046 * device, and page them all in. in uvm, swap-backed pageable 1047 * memory can take two forms: aobjs and anons. call the 1048 * swapoff hook for each subsystem to bring in pages. 1049 */ 1050 1051 if (uao_swap_off(sdp->swd_drumoffset, 1052 sdp->swd_drumoffset + sdp->swd_drumsize) || 1053 amap_swap_off(sdp->swd_drumoffset, 1054 sdp->swd_drumoffset + sdp->swd_drumsize)) { 1055 error = ENOMEM; 1056 } else if (sdp->swd_npginuse > sdp->swd_npgbad) { 1057 error = EBUSY; 1058 } 1059 1060 if (error) { 1061 mutex_enter(&uvm_swap_data_lock); 1062 sdp->swd_flags |= SWF_ENABLE; 1063 uvmexp.swpgavail += npages; 1064 mutex_exit(&uvm_swap_data_lock); 1065 1066 return error; 1067 } 1068 1069 /* 1070 * If this is the last regular swap destroy the workqueue. 1071 * => Protected by swap_syscall_lock. 1072 */ 1073 if (sdp->swd_vp->v_type != VBLK) { 1074 KASSERT(sw_reg_count > 0); 1075 KASSERT(sw_reg_workqueue != NULL); 1076 if (--sw_reg_count == 0) { 1077 workqueue_destroy(sw_reg_workqueue); 1078 sw_reg_workqueue = NULL; 1079 } 1080 } 1081 1082 /* 1083 * done with the vnode. 1084 * drop our ref on the vnode before calling VOP_CLOSE() 1085 * so that spec_close() can tell if this is the last close. 1086 */ 1087 vrele(sdp->swd_vp); 1088 if (sdp->swd_vp != rootvp) { 1089 (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, l->l_cred); 1090 } 1091 1092 mutex_enter(&uvm_swap_data_lock); 1093 uvmexp.swpages -= npages; 1094 uvmexp.swpginuse -= sdp->swd_npgbad; 1095 1096 if (swaplist_find(sdp->swd_vp, true) == NULL) 1097 panic("%s: swapdev not in list", __func__); 1098 swaplist_trim(); 1099 mutex_exit(&uvm_swap_data_lock); 1100 1101 /* 1102 * free all resources! 1103 */ 1104 vmem_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize); 1105 blist_destroy(sdp->swd_blist); 1106 bufq_free(sdp->swd_tab); 1107 kmem_free(sdp, sizeof(*sdp)); 1108 return (0); 1109 } 1110 1111 /* 1112 * /dev/drum interface and i/o functions 1113 */ 1114 1115 /* 1116 * swstrategy: perform I/O on the drum 1117 * 1118 * => we must map the i/o request from the drum to the correct swapdev. 1119 */ 1120 static void 1121 swstrategy(struct buf *bp) 1122 { 1123 struct swapdev *sdp; 1124 struct vnode *vp; 1125 int pageno, bn; 1126 UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); 1127 1128 /* 1129 * convert block number to swapdev. note that swapdev can't 1130 * be yanked out from under us because we are holding resources 1131 * in it (i.e. the blocks we are doing I/O on). 1132 */ 1133 pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; 1134 mutex_enter(&uvm_swap_data_lock); 1135 sdp = swapdrum_getsdp(pageno); 1136 mutex_exit(&uvm_swap_data_lock); 1137 if (sdp == NULL) { 1138 bp->b_error = EINVAL; 1139 bp->b_resid = bp->b_bcount; 1140 biodone(bp); 1141 UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); 1142 return; 1143 } 1144 1145 /* 1146 * convert drum page number to block number on this swapdev. 1147 */ 1148 1149 pageno -= sdp->swd_drumoffset; /* page # on swapdev */ 1150 bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ 1151 1152 UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld", 1153 ((bp->b_flags & B_READ) == 0) ? "write" : "read", 1154 sdp->swd_drumoffset, bn, bp->b_bcount); 1155 1156 /* 1157 * for block devices we finish up here. 1158 * for regular files we have to do more work which we delegate 1159 * to sw_reg_strategy(). 1160 */ 1161 1162 vp = sdp->swd_vp; /* swapdev vnode pointer */ 1163 switch (vp->v_type) { 1164 default: 1165 panic("%s: vnode type 0x%x", __func__, vp->v_type); 1166 1167 case VBLK: 1168 1169 /* 1170 * must convert "bp" from an I/O on /dev/drum to an I/O 1171 * on the swapdev (sdp). 1172 */ 1173 bp->b_blkno = bn; /* swapdev block number */ 1174 bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ 1175 1176 /* 1177 * if we are doing a write, we have to redirect the i/o on 1178 * drum's v_numoutput counter to the swapdevs. 1179 */ 1180 if ((bp->b_flags & B_READ) == 0) { 1181 mutex_enter(bp->b_objlock); 1182 vwakeup(bp); /* kills one 'v_numoutput' on drum */ 1183 mutex_exit(bp->b_objlock); 1184 mutex_enter(vp->v_interlock); 1185 vp->v_numoutput++; /* put it on swapdev */ 1186 mutex_exit(vp->v_interlock); 1187 } 1188 1189 /* 1190 * finally plug in swapdev vnode and start I/O 1191 */ 1192 bp->b_vp = vp; 1193 bp->b_objlock = vp->v_interlock; 1194 VOP_STRATEGY(vp, bp); 1195 return; 1196 1197 case VREG: 1198 /* 1199 * delegate to sw_reg_strategy function. 1200 */ 1201 sw_reg_strategy(sdp, bp, bn); 1202 return; 1203 } 1204 /* NOTREACHED */ 1205 } 1206 1207 /* 1208 * swread: the read function for the drum (just a call to physio) 1209 */ 1210 /*ARGSUSED*/ 1211 static int 1212 swread(dev_t dev, struct uio *uio, int ioflag) 1213 { 1214 UVMHIST_FUNC("swread"); UVMHIST_CALLED(pdhist); 1215 1216 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1217 return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); 1218 } 1219 1220 /* 1221 * swwrite: the write function for the drum (just a call to physio) 1222 */ 1223 /*ARGSUSED*/ 1224 static int 1225 swwrite(dev_t dev, struct uio *uio, int ioflag) 1226 { 1227 UVMHIST_FUNC("swwrite"); UVMHIST_CALLED(pdhist); 1228 1229 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1230 return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); 1231 } 1232 1233 const struct bdevsw swap_bdevsw = { 1234 nullopen, nullclose, swstrategy, noioctl, nodump, nosize, D_OTHER, 1235 }; 1236 1237 const struct cdevsw swap_cdevsw = { 1238 nullopen, nullclose, swread, swwrite, noioctl, 1239 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER, 1240 }; 1241 1242 /* 1243 * sw_reg_strategy: handle swap i/o to regular files 1244 */ 1245 static void 1246 sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) 1247 { 1248 struct vnode *vp; 1249 struct vndxfer *vnx; 1250 daddr_t nbn; 1251 char *addr; 1252 off_t byteoff; 1253 int s, off, nra, error, sz, resid; 1254 UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); 1255 1256 /* 1257 * allocate a vndxfer head for this transfer and point it to 1258 * our buffer. 1259 */ 1260 vnx = pool_get(&vndxfer_pool, PR_WAITOK); 1261 vnx->vx_flags = VX_BUSY; 1262 vnx->vx_error = 0; 1263 vnx->vx_pending = 0; 1264 vnx->vx_bp = bp; 1265 vnx->vx_sdp = sdp; 1266 1267 /* 1268 * setup for main loop where we read filesystem blocks into 1269 * our buffer. 1270 */ 1271 error = 0; 1272 bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ 1273 addr = bp->b_data; /* current position in buffer */ 1274 byteoff = dbtob((uint64_t)bn); 1275 1276 for (resid = bp->b_resid; resid; resid -= sz) { 1277 struct vndbuf *nbp; 1278 1279 /* 1280 * translate byteoffset into block number. return values: 1281 * vp = vnode of underlying device 1282 * nbn = new block number (on underlying vnode dev) 1283 * nra = num blocks we can read-ahead (excludes requested 1284 * block) 1285 */ 1286 nra = 0; 1287 error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, 1288 &vp, &nbn, &nra); 1289 1290 if (error == 0 && nbn == (daddr_t)-1) { 1291 /* 1292 * this used to just set error, but that doesn't 1293 * do the right thing. Instead, it causes random 1294 * memory errors. The panic() should remain until 1295 * this condition doesn't destabilize the system. 1296 */ 1297 #if 1 1298 panic("%s: swap to sparse file", __func__); 1299 #else 1300 error = EIO; /* failure */ 1301 #endif 1302 } 1303 1304 /* 1305 * punt if there was an error or a hole in the file. 1306 * we must wait for any i/o ops we have already started 1307 * to finish before returning. 1308 * 1309 * XXX we could deal with holes here but it would be 1310 * a hassle (in the write case). 1311 */ 1312 if (error) { 1313 s = splbio(); 1314 vnx->vx_error = error; /* pass error up */ 1315 goto out; 1316 } 1317 1318 /* 1319 * compute the size ("sz") of this transfer (in bytes). 1320 */ 1321 off = byteoff % sdp->swd_bsize; 1322 sz = (1 + nra) * sdp->swd_bsize - off; 1323 if (sz > resid) 1324 sz = resid; 1325 1326 UVMHIST_LOG(pdhist, "sw_reg_strategy: " 1327 "vp %p/%p offset 0x%x/0x%x", 1328 sdp->swd_vp, vp, byteoff, nbn); 1329 1330 /* 1331 * now get a buf structure. note that the vb_buf is 1332 * at the front of the nbp structure so that you can 1333 * cast pointers between the two structure easily. 1334 */ 1335 nbp = pool_get(&vndbuf_pool, PR_WAITOK); 1336 buf_init(&nbp->vb_buf); 1337 nbp->vb_buf.b_flags = bp->b_flags; 1338 nbp->vb_buf.b_cflags = bp->b_cflags; 1339 nbp->vb_buf.b_oflags = bp->b_oflags; 1340 nbp->vb_buf.b_bcount = sz; 1341 nbp->vb_buf.b_bufsize = sz; 1342 nbp->vb_buf.b_error = 0; 1343 nbp->vb_buf.b_data = addr; 1344 nbp->vb_buf.b_lblkno = 0; 1345 nbp->vb_buf.b_blkno = nbn + btodb(off); 1346 nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; 1347 nbp->vb_buf.b_iodone = sw_reg_biodone; 1348 nbp->vb_buf.b_vp = vp; 1349 nbp->vb_buf.b_objlock = vp->v_interlock; 1350 if (vp->v_type == VBLK) { 1351 nbp->vb_buf.b_dev = vp->v_rdev; 1352 } 1353 1354 nbp->vb_xfer = vnx; /* patch it back in to vnx */ 1355 1356 /* 1357 * Just sort by block number 1358 */ 1359 s = splbio(); 1360 if (vnx->vx_error != 0) { 1361 buf_destroy(&nbp->vb_buf); 1362 pool_put(&vndbuf_pool, nbp); 1363 goto out; 1364 } 1365 vnx->vx_pending++; 1366 1367 /* sort it in and start I/O if we are not over our limit */ 1368 /* XXXAD locking */ 1369 bufq_put(sdp->swd_tab, &nbp->vb_buf); 1370 sw_reg_start(sdp); 1371 splx(s); 1372 1373 /* 1374 * advance to the next I/O 1375 */ 1376 byteoff += sz; 1377 addr += sz; 1378 } 1379 1380 s = splbio(); 1381 1382 out: /* Arrive here at splbio */ 1383 vnx->vx_flags &= ~VX_BUSY; 1384 if (vnx->vx_pending == 0) { 1385 error = vnx->vx_error; 1386 pool_put(&vndxfer_pool, vnx); 1387 bp->b_error = error; 1388 biodone(bp); 1389 } 1390 splx(s); 1391 } 1392 1393 /* 1394 * sw_reg_start: start an I/O request on the requested swapdev 1395 * 1396 * => reqs are sorted by b_rawblkno (above) 1397 */ 1398 static void 1399 sw_reg_start(struct swapdev *sdp) 1400 { 1401 struct buf *bp; 1402 struct vnode *vp; 1403 UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); 1404 1405 /* recursion control */ 1406 if ((sdp->swd_flags & SWF_BUSY) != 0) 1407 return; 1408 1409 sdp->swd_flags |= SWF_BUSY; 1410 1411 while (sdp->swd_active < sdp->swd_maxactive) { 1412 bp = bufq_get(sdp->swd_tab); 1413 if (bp == NULL) 1414 break; 1415 sdp->swd_active++; 1416 1417 UVMHIST_LOG(pdhist, 1418 "sw_reg_start: bp %p vp %p blkno %p cnt %lx", 1419 bp, bp->b_vp, bp->b_blkno, bp->b_bcount); 1420 vp = bp->b_vp; 1421 KASSERT(bp->b_objlock == vp->v_interlock); 1422 if ((bp->b_flags & B_READ) == 0) { 1423 mutex_enter(vp->v_interlock); 1424 vp->v_numoutput++; 1425 mutex_exit(vp->v_interlock); 1426 } 1427 VOP_STRATEGY(vp, bp); 1428 } 1429 sdp->swd_flags &= ~SWF_BUSY; 1430 } 1431 1432 /* 1433 * sw_reg_biodone: one of our i/o's has completed 1434 */ 1435 static void 1436 sw_reg_biodone(struct buf *bp) 1437 { 1438 workqueue_enqueue(sw_reg_workqueue, &bp->b_work, NULL); 1439 } 1440 1441 /* 1442 * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup 1443 * 1444 * => note that we can recover the vndbuf struct by casting the buf ptr 1445 */ 1446 static void 1447 sw_reg_iodone(struct work *wk, void *dummy) 1448 { 1449 struct vndbuf *vbp = (void *)wk; 1450 struct vndxfer *vnx = vbp->vb_xfer; 1451 struct buf *pbp = vnx->vx_bp; /* parent buffer */ 1452 struct swapdev *sdp = vnx->vx_sdp; 1453 int s, resid, error; 1454 KASSERT(&vbp->vb_buf.b_work == wk); 1455 UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); 1456 1457 UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p", 1458 vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); 1459 UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", 1460 vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); 1461 1462 /* 1463 * protect vbp at splbio and update. 1464 */ 1465 1466 s = splbio(); 1467 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 1468 pbp->b_resid -= resid; 1469 vnx->vx_pending--; 1470 1471 if (vbp->vb_buf.b_error != 0) { 1472 /* pass error upward */ 1473 error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; 1474 UVMHIST_LOG(pdhist, " got error=%d !", error, 0, 0, 0); 1475 vnx->vx_error = error; 1476 } 1477 1478 /* 1479 * kill vbp structure 1480 */ 1481 buf_destroy(&vbp->vb_buf); 1482 pool_put(&vndbuf_pool, vbp); 1483 1484 /* 1485 * wrap up this transaction if it has run to completion or, in 1486 * case of an error, when all auxiliary buffers have returned. 1487 */ 1488 if (vnx->vx_error != 0) { 1489 /* pass error upward */ 1490 error = vnx->vx_error; 1491 if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { 1492 pbp->b_error = error; 1493 biodone(pbp); 1494 pool_put(&vndxfer_pool, vnx); 1495 } 1496 } else if (pbp->b_resid == 0) { 1497 KASSERT(vnx->vx_pending == 0); 1498 if ((vnx->vx_flags & VX_BUSY) == 0) { 1499 UVMHIST_LOG(pdhist, " iodone error=%d !", 1500 pbp, vnx->vx_error, 0, 0); 1501 biodone(pbp); 1502 pool_put(&vndxfer_pool, vnx); 1503 } 1504 } 1505 1506 /* 1507 * done! start next swapdev I/O if one is pending 1508 */ 1509 sdp->swd_active--; 1510 sw_reg_start(sdp); 1511 splx(s); 1512 } 1513 1514 1515 /* 1516 * uvm_swap_alloc: allocate space on swap 1517 * 1518 * => allocation is done "round robin" down the priority list, as we 1519 * allocate in a priority we "rotate" the circle queue. 1520 * => space can be freed with uvm_swap_free 1521 * => we return the page slot number in /dev/drum (0 == invalid slot) 1522 * => we lock uvm_swap_data_lock 1523 * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM 1524 */ 1525 int 1526 uvm_swap_alloc(int *nslots /* IN/OUT */, bool lessok) 1527 { 1528 struct swapdev *sdp; 1529 struct swappri *spp; 1530 UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); 1531 1532 /* 1533 * no swap devices configured yet? definite failure. 1534 */ 1535 if (uvmexp.nswapdev < 1) 1536 return 0; 1537 1538 /* 1539 * XXXJAK: BEGIN HACK 1540 * 1541 * blist_alloc() in subr_blist.c will panic if we try to allocate 1542 * too many slots. 1543 */ 1544 if (*nslots > BLIST_MAX_ALLOC) { 1545 if (__predict_false(lessok == false)) 1546 return 0; 1547 *nslots = BLIST_MAX_ALLOC; 1548 } 1549 /* XXXJAK: END HACK */ 1550 1551 /* 1552 * lock data lock, convert slots into blocks, and enter loop 1553 */ 1554 mutex_enter(&uvm_swap_data_lock); 1555 1556 ReTry: /* XXXMRG */ 1557 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 1558 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 1559 uint64_t result; 1560 1561 /* if it's not enabled, then we can't swap from it */ 1562 if ((sdp->swd_flags & SWF_ENABLE) == 0) 1563 continue; 1564 if (sdp->swd_npginuse + *nslots > sdp->swd_npages) 1565 continue; 1566 result = blist_alloc(sdp->swd_blist, *nslots); 1567 if (result == BLIST_NONE) { 1568 continue; 1569 } 1570 KASSERT(result < sdp->swd_drumsize); 1571 1572 /* 1573 * successful allocation! now rotate the circleq. 1574 */ 1575 CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); 1576 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 1577 sdp->swd_npginuse += *nslots; 1578 uvmexp.swpginuse += *nslots; 1579 mutex_exit(&uvm_swap_data_lock); 1580 /* done! return drum slot number */ 1581 UVMHIST_LOG(pdhist, 1582 "success! returning %d slots starting at %d", 1583 *nslots, result + sdp->swd_drumoffset, 0, 0); 1584 return (result + sdp->swd_drumoffset); 1585 } 1586 } 1587 1588 /* XXXMRG: BEGIN HACK */ 1589 if (*nslots > 1 && lessok) { 1590 *nslots = 1; 1591 /* XXXMRG: ugh! blist should support this for us */ 1592 goto ReTry; 1593 } 1594 /* XXXMRG: END HACK */ 1595 1596 mutex_exit(&uvm_swap_data_lock); 1597 return 0; 1598 } 1599 1600 /* 1601 * uvm_swapisfull: return true if most of available swap is allocated 1602 * and in use. we don't count some small portion as it may be inaccessible 1603 * to us at any given moment, for example if there is lock contention or if 1604 * pages are busy. 1605 */ 1606 bool 1607 uvm_swapisfull(void) 1608 { 1609 int swpgonly; 1610 bool rv; 1611 1612 mutex_enter(&uvm_swap_data_lock); 1613 KASSERT(uvmexp.swpgonly <= uvmexp.swpages); 1614 swpgonly = (int)((uint64_t)uvmexp.swpgonly * 100 / 1615 uvm_swapisfull_factor); 1616 rv = (swpgonly >= uvmexp.swpgavail); 1617 mutex_exit(&uvm_swap_data_lock); 1618 1619 return (rv); 1620 } 1621 1622 /* 1623 * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors 1624 * 1625 * => we lock uvm_swap_data_lock 1626 */ 1627 void 1628 uvm_swap_markbad(int startslot, int nslots) 1629 { 1630 struct swapdev *sdp; 1631 UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); 1632 1633 mutex_enter(&uvm_swap_data_lock); 1634 sdp = swapdrum_getsdp(startslot); 1635 KASSERT(sdp != NULL); 1636 1637 /* 1638 * we just keep track of how many pages have been marked bad 1639 * in this device, to make everything add up in swap_off(). 1640 * we assume here that the range of slots will all be within 1641 * one swap device. 1642 */ 1643 1644 KASSERT(uvmexp.swpgonly >= nslots); 1645 uvmexp.swpgonly -= nslots; 1646 sdp->swd_npgbad += nslots; 1647 UVMHIST_LOG(pdhist, "now %d bad", sdp->swd_npgbad, 0,0,0); 1648 mutex_exit(&uvm_swap_data_lock); 1649 } 1650 1651 /* 1652 * uvm_swap_free: free swap slots 1653 * 1654 * => this can be all or part of an allocation made by uvm_swap_alloc 1655 * => we lock uvm_swap_data_lock 1656 */ 1657 void 1658 uvm_swap_free(int startslot, int nslots) 1659 { 1660 struct swapdev *sdp; 1661 UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); 1662 1663 UVMHIST_LOG(pdhist, "freeing %d slots starting at %d", nslots, 1664 startslot, 0, 0); 1665 1666 /* 1667 * ignore attempts to free the "bad" slot. 1668 */ 1669 1670 if (startslot == SWSLOT_BAD) { 1671 return; 1672 } 1673 1674 /* 1675 * convert drum slot offset back to sdp, free the blocks 1676 * in the extent, and return. must hold pri lock to do 1677 * lookup and access the extent. 1678 */ 1679 1680 mutex_enter(&uvm_swap_data_lock); 1681 sdp = swapdrum_getsdp(startslot); 1682 KASSERT(uvmexp.nswapdev >= 1); 1683 KASSERT(sdp != NULL); 1684 KASSERT(sdp->swd_npginuse >= nslots); 1685 blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); 1686 sdp->swd_npginuse -= nslots; 1687 uvmexp.swpginuse -= nslots; 1688 mutex_exit(&uvm_swap_data_lock); 1689 } 1690 1691 /* 1692 * uvm_swap_put: put any number of pages into a contig place on swap 1693 * 1694 * => can be sync or async 1695 */ 1696 1697 int 1698 uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) 1699 { 1700 int error; 1701 1702 error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | 1703 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1704 return error; 1705 } 1706 1707 /* 1708 * uvm_swap_get: get a single page from swap 1709 * 1710 * => usually a sync op (from fault) 1711 */ 1712 1713 int 1714 uvm_swap_get(struct vm_page *page, int swslot, int flags) 1715 { 1716 int error; 1717 1718 uvmexp.nswget++; 1719 KASSERT(flags & PGO_SYNCIO); 1720 if (swslot == SWSLOT_BAD) { 1721 return EIO; 1722 } 1723 1724 error = uvm_swap_io(&page, swslot, 1, B_READ | 1725 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1726 if (error == 0) { 1727 1728 /* 1729 * this page is no longer only in swap. 1730 */ 1731 1732 mutex_enter(&uvm_swap_data_lock); 1733 KASSERT(uvmexp.swpgonly > 0); 1734 uvmexp.swpgonly--; 1735 mutex_exit(&uvm_swap_data_lock); 1736 } 1737 return error; 1738 } 1739 1740 /* 1741 * uvm_swap_io: do an i/o operation to swap 1742 */ 1743 1744 static int 1745 uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) 1746 { 1747 daddr_t startblk; 1748 struct buf *bp; 1749 vaddr_t kva; 1750 int error, mapinflags; 1751 bool write, async; 1752 UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); 1753 1754 UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d", 1755 startslot, npages, flags, 0); 1756 1757 write = (flags & B_READ) == 0; 1758 async = (flags & B_ASYNC) != 0; 1759 1760 /* 1761 * allocate a buf for the i/o. 1762 */ 1763 1764 KASSERT(curlwp != uvm.pagedaemon_lwp || (write && async)); 1765 bp = getiobuf(swapdev_vp, curlwp != uvm.pagedaemon_lwp); 1766 if (bp == NULL) { 1767 uvm_aio_aiodone_pages(pps, npages, true, ENOMEM); 1768 return ENOMEM; 1769 } 1770 1771 /* 1772 * convert starting drum slot to block number 1773 */ 1774 1775 startblk = btodb((uint64_t)startslot << PAGE_SHIFT); 1776 1777 /* 1778 * first, map the pages into the kernel. 1779 */ 1780 1781 mapinflags = !write ? 1782 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : 1783 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; 1784 kva = uvm_pagermapin(pps, npages, mapinflags); 1785 1786 /* 1787 * fill in the bp/sbp. we currently route our i/o through 1788 * /dev/drum's vnode [swapdev_vp]. 1789 */ 1790 1791 bp->b_cflags = BC_BUSY | BC_NOCACHE; 1792 bp->b_flags = (flags & (B_READ|B_ASYNC)); 1793 bp->b_proc = &proc0; /* XXX */ 1794 bp->b_vnbufs.le_next = NOLIST; 1795 bp->b_data = (void *)kva; 1796 bp->b_blkno = startblk; 1797 bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; 1798 1799 /* 1800 * bump v_numoutput (counter of number of active outputs). 1801 */ 1802 1803 if (write) { 1804 mutex_enter(swapdev_vp->v_interlock); 1805 swapdev_vp->v_numoutput++; 1806 mutex_exit(swapdev_vp->v_interlock); 1807 } 1808 1809 /* 1810 * for async ops we must set up the iodone handler. 1811 */ 1812 1813 if (async) { 1814 bp->b_iodone = uvm_aio_biodone; 1815 UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); 1816 if (curlwp == uvm.pagedaemon_lwp) 1817 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1818 else 1819 BIO_SETPRIO(bp, BPRIO_TIMELIMITED); 1820 } else { 1821 bp->b_iodone = NULL; 1822 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1823 } 1824 UVMHIST_LOG(pdhist, 1825 "about to start io: data = %p blkno = 0x%x, bcount = %ld", 1826 bp->b_data, bp->b_blkno, bp->b_bcount, 0); 1827 1828 /* 1829 * now we start the I/O, and if async, return. 1830 */ 1831 1832 VOP_STRATEGY(swapdev_vp, bp); 1833 if (async) 1834 return 0; 1835 1836 /* 1837 * must be sync i/o. wait for it to finish 1838 */ 1839 1840 error = biowait(bp); 1841 1842 /* 1843 * kill the pager mapping 1844 */ 1845 1846 uvm_pagermapout(kva, npages); 1847 1848 /* 1849 * now dispose of the buf and we're done. 1850 */ 1851 1852 if (write) { 1853 mutex_enter(swapdev_vp->v_interlock); 1854 vwakeup(bp); 1855 mutex_exit(swapdev_vp->v_interlock); 1856 } 1857 putiobuf(bp); 1858 UVMHIST_LOG(pdhist, "<- done (sync) error=%d", error, 0, 0, 0); 1859 1860 return (error); 1861 } 1862