1 /* $NetBSD: uvm_swap.c,v 1.149 2010/02/07 15:51:28 mlelstv 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 1.149 2010/02/07 15:51:28 mlelstv Exp $"); 34 35 #include "fs_nfs.h" 36 #include "opt_uvmhist.h" 37 #include "opt_compat_netbsd.h" 38 #include "opt_ddb.h" 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/buf.h> 43 #include <sys/bufq.h> 44 #include <sys/conf.h> 45 #include <sys/proc.h> 46 #include <sys/namei.h> 47 #include <sys/disklabel.h> 48 #include <sys/errno.h> 49 #include <sys/kernel.h> 50 #include <sys/malloc.h> 51 #include <sys/vnode.h> 52 #include <sys/file.h> 53 #include <sys/vmem.h> 54 #include <sys/blist.h> 55 #include <sys/mount.h> 56 #include <sys/pool.h> 57 #include <sys/syscallargs.h> 58 #include <sys/swap.h> 59 #include <sys/kauth.h> 60 #include <sys/sysctl.h> 61 #include <sys/workqueue.h> 62 63 #include <uvm/uvm.h> 64 65 #include <miscfs/specfs/specdev.h> 66 67 /* 68 * uvm_swap.c: manage configuration and i/o to swap space. 69 */ 70 71 /* 72 * swap space is managed in the following way: 73 * 74 * each swap partition or file is described by a "swapdev" structure. 75 * each "swapdev" structure contains a "swapent" structure which contains 76 * information that is passed up to the user (via system calls). 77 * 78 * each swap partition is assigned a "priority" (int) which controls 79 * swap parition usage. 80 * 81 * the system maintains a global data structure describing all swap 82 * partitions/files. there is a sorted LIST of "swappri" structures 83 * which describe "swapdev"'s at that priority. this LIST is headed 84 * by the "swap_priority" global var. each "swappri" contains a 85 * CIRCLEQ of "swapdev" structures at that priority. 86 * 87 * locking: 88 * - swap_syscall_lock (krwlock_t): this lock serializes the swapctl 89 * system call and prevents the swap priority list from changing 90 * while we are in the middle of a system call (e.g. SWAP_STATS). 91 * - uvm_swap_data_lock (kmutex_t): this lock protects all swap data 92 * structures including the priority list, the swapdev structures, 93 * and the swapmap arena. 94 * 95 * each swap device has the following info: 96 * - swap device in use (could be disabled, preventing future use) 97 * - swap enabled (allows new allocations on swap) 98 * - map info in /dev/drum 99 * - vnode pointer 100 * for swap files only: 101 * - block size 102 * - max byte count in buffer 103 * - buffer 104 * 105 * userland controls and configures swap with the swapctl(2) system call. 106 * the sys_swapctl performs the following operations: 107 * [1] SWAP_NSWAP: returns the number of swap devices currently configured 108 * [2] SWAP_STATS: given a pointer to an array of swapent structures 109 * (passed in via "arg") of a size passed in via "misc" ... we load 110 * the current swap config into the array. The actual work is done 111 * in the uvm_swap_stats(9) function. 112 * [3] SWAP_ON: given a pathname in arg (could be device or file) and a 113 * priority in "misc", start swapping on it. 114 * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device 115 * [5] SWAP_CTL: changes the priority of a swap device (new priority in 116 * "misc") 117 */ 118 119 /* 120 * swapdev: describes a single swap partition/file 121 * 122 * note the following should be true: 123 * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] 124 * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] 125 */ 126 struct swapdev { 127 dev_t swd_dev; /* device id */ 128 int swd_flags; /* flags:inuse/enable/fake */ 129 int swd_priority; /* our priority */ 130 int swd_nblks; /* blocks in this device */ 131 char *swd_path; /* saved pathname of device */ 132 int swd_pathlen; /* length of pathname */ 133 int swd_npages; /* #pages we can use */ 134 int swd_npginuse; /* #pages in use */ 135 int swd_npgbad; /* #pages bad */ 136 int swd_drumoffset; /* page0 offset in drum */ 137 int swd_drumsize; /* #pages in drum */ 138 blist_t swd_blist; /* blist for this swapdev */ 139 struct vnode *swd_vp; /* backing vnode */ 140 CIRCLEQ_ENTRY(swapdev) swd_next; /* priority circleq */ 141 142 int swd_bsize; /* blocksize (bytes) */ 143 int swd_maxactive; /* max active i/o reqs */ 144 struct bufq_state *swd_tab; /* buffer list */ 145 int swd_active; /* number of active buffers */ 146 }; 147 148 /* 149 * swap device priority entry; the list is kept sorted on `spi_priority'. 150 */ 151 struct swappri { 152 int spi_priority; /* priority */ 153 CIRCLEQ_HEAD(spi_swapdev, swapdev) spi_swapdev; 154 /* circleq of swapdevs at this priority */ 155 LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ 156 }; 157 158 /* 159 * The following two structures are used to keep track of data transfers 160 * on swap devices associated with regular files. 161 * NOTE: this code is more or less a copy of vnd.c; we use the same 162 * structure names here to ease porting.. 163 */ 164 struct vndxfer { 165 struct buf *vx_bp; /* Pointer to parent buffer */ 166 struct swapdev *vx_sdp; 167 int vx_error; 168 int vx_pending; /* # of pending aux buffers */ 169 int vx_flags; 170 #define VX_BUSY 1 171 #define VX_DEAD 2 172 }; 173 174 struct vndbuf { 175 struct buf vb_buf; 176 struct vndxfer *vb_xfer; 177 }; 178 179 /* 180 * NetBSD 1.3 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit 181 * dev_t and has no se_path[] member. 182 */ 183 struct swapent13 { 184 int32_t se13_dev; /* device id */ 185 int se13_flags; /* flags */ 186 int se13_nblks; /* total blocks */ 187 int se13_inuse; /* blocks in use */ 188 int se13_priority; /* priority of this device */ 189 }; 190 191 /* 192 * NetBSD 5.0 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit 193 * dev_t. 194 */ 195 struct swapent50 { 196 int32_t se50_dev; /* device id */ 197 int se50_flags; /* flags */ 198 int se50_nblks; /* total blocks */ 199 int se50_inuse; /* blocks in use */ 200 int se50_priority; /* priority of this device */ 201 char se50_path[PATH_MAX+1]; /* path name */ 202 }; 203 204 /* 205 * We keep a of pool vndbuf's and vndxfer structures. 206 */ 207 static struct pool vndxfer_pool, vndbuf_pool; 208 209 /* 210 * local variables 211 */ 212 MALLOC_DEFINE(M_VMSWAP, "VM swap", "VM swap structures"); 213 static vmem_t *swapmap; /* controls the mapping of /dev/drum */ 214 215 /* list of all active swap devices [by priority] */ 216 LIST_HEAD(swap_priority, swappri); 217 static struct swap_priority swap_priority; 218 219 /* locks */ 220 static krwlock_t swap_syscall_lock; 221 222 /* workqueue and use counter for swap to regular files */ 223 static int sw_reg_count = 0; 224 static struct workqueue *sw_reg_workqueue; 225 226 /* tuneables */ 227 u_int uvm_swapisfull_factor = 99; 228 229 /* 230 * prototypes 231 */ 232 static struct swapdev *swapdrum_getsdp(int); 233 234 static struct swapdev *swaplist_find(struct vnode *, bool); 235 static void swaplist_insert(struct swapdev *, 236 struct swappri *, int); 237 static void swaplist_trim(void); 238 239 static int swap_on(struct lwp *, struct swapdev *); 240 static int swap_off(struct lwp *, struct swapdev *); 241 242 static void uvm_swap_stats_locked(int, struct swapent *, int, register_t *); 243 244 static void sw_reg_strategy(struct swapdev *, struct buf *, int); 245 static void sw_reg_biodone(struct buf *); 246 static void sw_reg_iodone(struct work *wk, void *dummy); 247 static void sw_reg_start(struct swapdev *); 248 249 static int uvm_swap_io(struct vm_page **, int, int, int); 250 251 /* 252 * uvm_swap_init: init the swap system data structures and locks 253 * 254 * => called at boot time from init_main.c after the filesystems 255 * are brought up (which happens after uvm_init()) 256 */ 257 void 258 uvm_swap_init(void) 259 { 260 UVMHIST_FUNC("uvm_swap_init"); 261 262 UVMHIST_CALLED(pdhist); 263 /* 264 * first, init the swap list, its counter, and its lock. 265 * then get a handle on the vnode for /dev/drum by using 266 * the its dev_t number ("swapdev", from MD conf.c). 267 */ 268 269 LIST_INIT(&swap_priority); 270 uvmexp.nswapdev = 0; 271 rw_init(&swap_syscall_lock); 272 mutex_init(&uvm_swap_data_lock, MUTEX_DEFAULT, IPL_NONE); 273 274 if (bdevvp(swapdev, &swapdev_vp)) 275 panic("%s: can't get vnode for swap device", __func__); 276 if (vn_lock(swapdev_vp, LK_EXCLUSIVE | LK_RETRY)) 277 panic("%s: can't lock swap device", __func__); 278 if (VOP_OPEN(swapdev_vp, FREAD | FWRITE, NOCRED)) 279 panic("%s: can't open swap device", __func__); 280 VOP_UNLOCK(swapdev_vp, 0); 281 282 /* 283 * create swap block resource map to map /dev/drum. the range 284 * from 1 to INT_MAX allows 2 gigablocks of swap space. note 285 * that block 0 is reserved (used to indicate an allocation 286 * failure, or no allocation). 287 */ 288 swapmap = vmem_create("swapmap", 1, INT_MAX - 1, 1, NULL, NULL, NULL, 0, 289 VM_NOSLEEP, IPL_NONE); 290 if (swapmap == 0) { 291 panic("%s: vmem_create failed", __func__); 292 } 293 294 pool_init(&vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", 295 NULL, IPL_BIO); 296 pool_init(&vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", 297 NULL, IPL_BIO); 298 299 UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); 300 } 301 302 /* 303 * swaplist functions: functions that operate on the list of swap 304 * devices on the system. 305 */ 306 307 /* 308 * swaplist_insert: insert swap device "sdp" into the global list 309 * 310 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 311 * => caller must provide a newly malloc'd swappri structure (we will 312 * FREE it if we don't need it... this it to prevent malloc blocking 313 * here while adding swap) 314 */ 315 static void 316 swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) 317 { 318 struct swappri *spp, *pspp; 319 UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); 320 321 /* 322 * find entry at or after which to insert the new device. 323 */ 324 pspp = NULL; 325 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 326 if (priority <= spp->spi_priority) 327 break; 328 pspp = spp; 329 } 330 331 /* 332 * new priority? 333 */ 334 if (spp == NULL || spp->spi_priority != priority) { 335 spp = newspp; /* use newspp! */ 336 UVMHIST_LOG(pdhist, "created new swappri = %d", 337 priority, 0, 0, 0); 338 339 spp->spi_priority = priority; 340 CIRCLEQ_INIT(&spp->spi_swapdev); 341 342 if (pspp) 343 LIST_INSERT_AFTER(pspp, spp, spi_swappri); 344 else 345 LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); 346 } else { 347 /* we don't need a new priority structure, free it */ 348 free(newspp, M_VMSWAP); 349 } 350 351 /* 352 * priority found (or created). now insert on the priority's 353 * circleq list and bump the total number of swapdevs. 354 */ 355 sdp->swd_priority = priority; 356 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 357 uvmexp.nswapdev++; 358 } 359 360 /* 361 * swaplist_find: find and optionally remove a swap device from the 362 * global list. 363 * 364 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 365 * => we return the swapdev we found (and removed) 366 */ 367 static struct swapdev * 368 swaplist_find(struct vnode *vp, bool remove) 369 { 370 struct swapdev *sdp; 371 struct swappri *spp; 372 373 /* 374 * search the lists for the requested vp 375 */ 376 377 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 378 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 379 if (sdp->swd_vp == vp) { 380 if (remove) { 381 CIRCLEQ_REMOVE(&spp->spi_swapdev, 382 sdp, swd_next); 383 uvmexp.nswapdev--; 384 } 385 return(sdp); 386 } 387 } 388 } 389 return (NULL); 390 } 391 392 /* 393 * swaplist_trim: scan priority list for empty priority entries and kill 394 * them. 395 * 396 * => caller must hold both swap_syscall_lock and uvm_swap_data_lock 397 */ 398 static void 399 swaplist_trim(void) 400 { 401 struct swappri *spp, *nextspp; 402 403 for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = nextspp) { 404 nextspp = LIST_NEXT(spp, spi_swappri); 405 if (CIRCLEQ_FIRST(&spp->spi_swapdev) != 406 (void *)&spp->spi_swapdev) 407 continue; 408 LIST_REMOVE(spp, spi_swappri); 409 free(spp, M_VMSWAP); 410 } 411 } 412 413 /* 414 * swapdrum_getsdp: given a page offset in /dev/drum, convert it back 415 * to the "swapdev" that maps that section of the drum. 416 * 417 * => each swapdev takes one big contig chunk of the drum 418 * => caller must hold uvm_swap_data_lock 419 */ 420 static struct swapdev * 421 swapdrum_getsdp(int pgno) 422 { 423 struct swapdev *sdp; 424 struct swappri *spp; 425 426 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 427 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 428 if (sdp->swd_flags & SWF_FAKE) 429 continue; 430 if (pgno >= sdp->swd_drumoffset && 431 pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { 432 return sdp; 433 } 434 } 435 } 436 return NULL; 437 } 438 439 440 /* 441 * sys_swapctl: main entry point for swapctl(2) system call 442 * [with two helper functions: swap_on and swap_off] 443 */ 444 int 445 sys_swapctl(struct lwp *l, const struct sys_swapctl_args *uap, register_t *retval) 446 { 447 /* { 448 syscallarg(int) cmd; 449 syscallarg(void *) arg; 450 syscallarg(int) misc; 451 } */ 452 struct vnode *vp; 453 struct nameidata nd; 454 struct swappri *spp; 455 struct swapdev *sdp; 456 struct swapent *sep; 457 #define SWAP_PATH_MAX (PATH_MAX + 1) 458 char *userpath; 459 size_t len; 460 int error, misc; 461 int priority; 462 UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); 463 464 misc = SCARG(uap, misc); 465 466 /* 467 * ensure serialized syscall access by grabbing the swap_syscall_lock 468 */ 469 rw_enter(&swap_syscall_lock, RW_WRITER); 470 471 userpath = malloc(SWAP_PATH_MAX, M_TEMP, M_WAITOK); 472 /* 473 * we handle the non-priv NSWAP and STATS request first. 474 * 475 * SWAP_NSWAP: return number of config'd swap devices 476 * [can also be obtained with uvmexp sysctl] 477 */ 478 if (SCARG(uap, cmd) == SWAP_NSWAP) { 479 UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d", uvmexp.nswapdev, 480 0, 0, 0); 481 *retval = uvmexp.nswapdev; 482 error = 0; 483 goto out; 484 } 485 486 /* 487 * SWAP_STATS: get stats on current # of configured swap devs 488 * 489 * note that the swap_priority list can't change as long 490 * as we are holding the swap_syscall_lock. we don't want 491 * to grab the uvm_swap_data_lock because we may fault&sleep during 492 * copyout() and we don't want to be holding that lock then! 493 */ 494 if (SCARG(uap, cmd) == SWAP_STATS 495 #if defined(COMPAT_50) 496 || SCARG(uap, cmd) == SWAP_STATS50 497 #endif 498 #if defined(COMPAT_13) 499 || SCARG(uap, cmd) == SWAP_STATS13 500 #endif 501 ) { 502 if ((size_t)misc > (size_t)uvmexp.nswapdev) 503 misc = uvmexp.nswapdev; 504 #if defined(COMPAT_13) 505 if (SCARG(uap, cmd) == SWAP_STATS13) 506 len = sizeof(struct swapent13) * misc; 507 else 508 #endif 509 #if defined(COMPAT_50) 510 if (SCARG(uap, cmd) == SWAP_STATS50) 511 len = sizeof(struct swapent50) * misc; 512 else 513 #endif 514 len = sizeof(struct swapent) * misc; 515 sep = (struct swapent *)malloc(len, M_TEMP, M_WAITOK); 516 517 uvm_swap_stats_locked(SCARG(uap, cmd), sep, misc, retval); 518 error = copyout(sep, SCARG(uap, arg), len); 519 520 free(sep, M_TEMP); 521 UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); 522 goto out; 523 } 524 if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { 525 dev_t *devp = (dev_t *)SCARG(uap, arg); 526 527 error = copyout(&dumpdev, devp, sizeof(dumpdev)); 528 goto out; 529 } 530 531 /* 532 * all other requests require superuser privs. verify. 533 */ 534 if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SWAPCTL, 535 0, NULL, NULL, NULL))) 536 goto out; 537 538 if (SCARG(uap, cmd) == SWAP_DUMPOFF) { 539 /* drop the current dump device */ 540 dumpdev = NODEV; 541 dumpcdev = NODEV; 542 cpu_dumpconf(); 543 goto out; 544 } 545 546 /* 547 * at this point we expect a path name in arg. we will 548 * use namei() to gain a vnode reference (vref), and lock 549 * the vnode (VOP_LOCK). 550 * 551 * XXX: a NULL arg means use the root vnode pointer (e.g. for 552 * miniroot) 553 */ 554 if (SCARG(uap, arg) == NULL) { 555 vp = rootvp; /* miniroot */ 556 if (vget(vp, LK_EXCLUSIVE)) { 557 error = EBUSY; 558 goto out; 559 } 560 if (SCARG(uap, cmd) == SWAP_ON && 561 copystr("miniroot", userpath, SWAP_PATH_MAX, &len)) 562 panic("swapctl: miniroot copy failed"); 563 } else { 564 int space; 565 char *where; 566 567 if (SCARG(uap, cmd) == SWAP_ON) { 568 if ((error = copyinstr(SCARG(uap, arg), userpath, 569 SWAP_PATH_MAX, &len))) 570 goto out; 571 space = UIO_SYSSPACE; 572 where = userpath; 573 } else { 574 space = UIO_USERSPACE; 575 where = (char *)SCARG(uap, arg); 576 } 577 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, 578 space, where); 579 if ((error = namei(&nd))) 580 goto out; 581 vp = nd.ni_vp; 582 } 583 /* note: "vp" is referenced and locked */ 584 585 error = 0; /* assume no error */ 586 switch(SCARG(uap, cmd)) { 587 588 case SWAP_DUMPDEV: 589 if (vp->v_type != VBLK) { 590 error = ENOTBLK; 591 break; 592 } 593 if (bdevsw_lookup(vp->v_rdev)) { 594 dumpdev = vp->v_rdev; 595 dumpcdev = devsw_blk2chr(dumpdev); 596 } else 597 dumpdev = NODEV; 598 cpu_dumpconf(); 599 break; 600 601 case SWAP_CTL: 602 /* 603 * get new priority, remove old entry (if any) and then 604 * reinsert it in the correct place. finally, prune out 605 * any empty priority structures. 606 */ 607 priority = SCARG(uap, misc); 608 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 609 mutex_enter(&uvm_swap_data_lock); 610 if ((sdp = swaplist_find(vp, true)) == NULL) { 611 error = ENOENT; 612 } else { 613 swaplist_insert(sdp, spp, priority); 614 swaplist_trim(); 615 } 616 mutex_exit(&uvm_swap_data_lock); 617 if (error) 618 free(spp, M_VMSWAP); 619 break; 620 621 case SWAP_ON: 622 623 /* 624 * check for duplicates. if none found, then insert a 625 * dummy entry on the list to prevent someone else from 626 * trying to enable this device while we are working on 627 * it. 628 */ 629 630 priority = SCARG(uap, misc); 631 sdp = malloc(sizeof *sdp, M_VMSWAP, M_WAITOK); 632 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 633 memset(sdp, 0, sizeof(*sdp)); 634 sdp->swd_flags = SWF_FAKE; 635 sdp->swd_vp = vp; 636 sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; 637 bufq_alloc(&sdp->swd_tab, "disksort", BUFQ_SORT_RAWBLOCK); 638 mutex_enter(&uvm_swap_data_lock); 639 if (swaplist_find(vp, false) != NULL) { 640 error = EBUSY; 641 mutex_exit(&uvm_swap_data_lock); 642 bufq_free(sdp->swd_tab); 643 free(sdp, M_VMSWAP); 644 free(spp, M_VMSWAP); 645 break; 646 } 647 swaplist_insert(sdp, spp, priority); 648 mutex_exit(&uvm_swap_data_lock); 649 650 sdp->swd_pathlen = len; 651 sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); 652 if (copystr(userpath, sdp->swd_path, sdp->swd_pathlen, 0) != 0) 653 panic("swapctl: copystr"); 654 655 /* 656 * we've now got a FAKE placeholder in the swap list. 657 * now attempt to enable swap on it. if we fail, undo 658 * what we've done and kill the fake entry we just inserted. 659 * if swap_on is a success, it will clear the SWF_FAKE flag 660 */ 661 662 if ((error = swap_on(l, sdp)) != 0) { 663 mutex_enter(&uvm_swap_data_lock); 664 (void) swaplist_find(vp, true); /* kill fake entry */ 665 swaplist_trim(); 666 mutex_exit(&uvm_swap_data_lock); 667 bufq_free(sdp->swd_tab); 668 free(sdp->swd_path, M_VMSWAP); 669 free(sdp, M_VMSWAP); 670 break; 671 } 672 break; 673 674 case SWAP_OFF: 675 mutex_enter(&uvm_swap_data_lock); 676 if ((sdp = swaplist_find(vp, false)) == NULL) { 677 mutex_exit(&uvm_swap_data_lock); 678 error = ENXIO; 679 break; 680 } 681 682 /* 683 * If a device isn't in use or enabled, we 684 * can't stop swapping from it (again). 685 */ 686 if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { 687 mutex_exit(&uvm_swap_data_lock); 688 error = EBUSY; 689 break; 690 } 691 692 /* 693 * do the real work. 694 */ 695 error = swap_off(l, sdp); 696 break; 697 698 default: 699 error = EINVAL; 700 } 701 702 /* 703 * done! release the ref gained by namei() and unlock. 704 */ 705 vput(vp); 706 707 out: 708 free(userpath, M_TEMP); 709 rw_exit(&swap_syscall_lock); 710 711 UVMHIST_LOG(pdhist, "<- done! error=%d", error, 0, 0, 0); 712 return (error); 713 } 714 715 /* 716 * swap_stats: implements swapctl(SWAP_STATS). The function is kept 717 * away from sys_swapctl() in order to allow COMPAT_* swapctl() 718 * emulation to use it directly without going through sys_swapctl(). 719 * The problem with using sys_swapctl() there is that it involves 720 * copying the swapent array to the stackgap, and this array's size 721 * is not known at build time. Hence it would not be possible to 722 * ensure it would fit in the stackgap in any case. 723 */ 724 void 725 uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) 726 { 727 728 rw_enter(&swap_syscall_lock, RW_READER); 729 uvm_swap_stats_locked(cmd, sep, sec, retval); 730 rw_exit(&swap_syscall_lock); 731 } 732 733 static void 734 uvm_swap_stats_locked(int cmd, struct swapent *sep, int sec, register_t *retval) 735 { 736 struct swappri *spp; 737 struct swapdev *sdp; 738 int count = 0; 739 740 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 741 for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); 742 sdp != (void *)&spp->spi_swapdev && sec-- > 0; 743 sdp = CIRCLEQ_NEXT(sdp, swd_next)) { 744 int inuse; 745 746 /* 747 * backwards compatibility for system call. 748 * For NetBSD 1.3 and 5.0, we have to use 749 * the 32 bit dev_t. For 5.0 and -current 750 * we have to add the path. 751 */ 752 inuse = btodb((uint64_t)sdp->swd_npginuse << 753 PAGE_SHIFT); 754 755 #if defined(COMPAT_13) || defined(COMPAT_50) 756 if (cmd == SWAP_STATS) { 757 #endif 758 sep->se_dev = sdp->swd_dev; 759 sep->se_flags = sdp->swd_flags; 760 sep->se_nblks = sdp->swd_nblks; 761 sep->se_inuse = inuse; 762 sep->se_priority = sdp->swd_priority; 763 memcpy(&sep->se_path, sdp->swd_path, 764 sizeof sep->se_path); 765 sep++; 766 #if defined(COMPAT_13) 767 } else if (cmd == SWAP_STATS13) { 768 struct swapent13 *sep13 = 769 (struct swapent13 *)sep; 770 771 sep13->se13_dev = sdp->swd_dev; 772 sep13->se13_flags = sdp->swd_flags; 773 sep13->se13_nblks = sdp->swd_nblks; 774 sep13->se13_inuse = inuse; 775 sep13->se13_priority = sdp->swd_priority; 776 sep = (struct swapent *)(sep13 + 1); 777 #endif 778 #if defined(COMPAT_50) 779 } else if (cmd == SWAP_STATS50) { 780 struct swapent50 *sep50 = 781 (struct swapent50 *)sep; 782 783 sep50->se50_dev = sdp->swd_dev; 784 sep50->se50_flags = sdp->swd_flags; 785 sep50->se50_nblks = sdp->swd_nblks; 786 sep50->se50_inuse = inuse; 787 sep50->se50_priority = sdp->swd_priority; 788 memcpy(&sep50->se50_path, sdp->swd_path, 789 sizeof sep50->se50_path); 790 sep = (struct swapent *)(sep50 + 1); 791 #endif 792 #if defined(COMPAT_13) || defined(COMPAT_50) 793 } 794 #endif 795 count++; 796 } 797 } 798 799 *retval = count; 800 return; 801 } 802 803 /* 804 * swap_on: attempt to enable a swapdev for swapping. note that the 805 * swapdev is already on the global list, but disabled (marked 806 * SWF_FAKE). 807 * 808 * => we avoid the start of the disk (to protect disk labels) 809 * => we also avoid the miniroot, if we are swapping to root. 810 * => caller should leave uvm_swap_data_lock unlocked, we may lock it 811 * if needed. 812 */ 813 static int 814 swap_on(struct lwp *l, struct swapdev *sdp) 815 { 816 struct vnode *vp; 817 int error, npages, nblocks, size; 818 long addr; 819 u_long result; 820 struct vattr va; 821 #ifdef NFS 822 extern int (**nfsv2_vnodeop_p)(void *); 823 #endif /* NFS */ 824 const struct bdevsw *bdev; 825 dev_t dev; 826 UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); 827 828 /* 829 * we want to enable swapping on sdp. the swd_vp contains 830 * the vnode we want (locked and ref'd), and the swd_dev 831 * contains the dev_t of the file, if it a block device. 832 */ 833 834 vp = sdp->swd_vp; 835 dev = sdp->swd_dev; 836 837 /* 838 * open the swap file (mostly useful for block device files to 839 * let device driver know what is up). 840 * 841 * we skip the open/close for root on swap because the root 842 * has already been opened when root was mounted (mountroot). 843 */ 844 if (vp != rootvp) { 845 if ((error = VOP_OPEN(vp, FREAD|FWRITE, l->l_cred))) 846 return (error); 847 } 848 849 /* XXX this only works for block devices */ 850 UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d", dev, major(dev), 0,0); 851 852 /* 853 * we now need to determine the size of the swap area. for 854 * block specials we can call the d_psize function. 855 * for normal files, we must stat [get attrs]. 856 * 857 * we put the result in nblks. 858 * for normal files, we also want the filesystem block size 859 * (which we get with statfs). 860 */ 861 switch (vp->v_type) { 862 case VBLK: 863 bdev = bdevsw_lookup(dev); 864 if (bdev == NULL || bdev->d_psize == NULL || 865 (nblocks = (*bdev->d_psize)(dev)) == -1) { 866 error = ENXIO; 867 goto bad; 868 } 869 break; 870 871 case VREG: 872 if ((error = VOP_GETATTR(vp, &va, l->l_cred))) 873 goto bad; 874 nblocks = (int)btodb(va.va_size); 875 sdp->swd_bsize = 1 << vp->v_mount->mnt_fs_bshift; 876 /* 877 * limit the max # of outstanding I/O requests we issue 878 * at any one time. take it easy on NFS servers. 879 */ 880 #ifdef NFS 881 if (vp->v_op == nfsv2_vnodeop_p) 882 sdp->swd_maxactive = 2; /* XXX */ 883 else 884 #endif /* NFS */ 885 sdp->swd_maxactive = 8; /* XXX */ 886 break; 887 888 default: 889 error = ENXIO; 890 goto bad; 891 } 892 893 /* 894 * save nblocks in a safe place and convert to pages. 895 */ 896 897 sdp->swd_nblks = nblocks; 898 npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; 899 900 /* 901 * for block special files, we want to make sure that leave 902 * the disklabel and bootblocks alone, so we arrange to skip 903 * over them (arbitrarily choosing to skip PAGE_SIZE bytes). 904 * note that because of this the "size" can be less than the 905 * actual number of blocks on the device. 906 */ 907 if (vp->v_type == VBLK) { 908 /* we use pages 1 to (size - 1) [inclusive] */ 909 size = npages - 1; 910 addr = 1; 911 } else { 912 /* we use pages 0 to (size - 1) [inclusive] */ 913 size = npages; 914 addr = 0; 915 } 916 917 /* 918 * make sure we have enough blocks for a reasonable sized swap 919 * area. we want at least one page. 920 */ 921 922 if (size < 1) { 923 UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); 924 error = EINVAL; 925 goto bad; 926 } 927 928 UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld\n", dev, size, addr, 0); 929 930 /* 931 * now we need to allocate an extent to manage this swap device 932 */ 933 934 sdp->swd_blist = blist_create(npages); 935 /* mark all expect the `saved' region free. */ 936 blist_free(sdp->swd_blist, addr, size); 937 938 /* 939 * if the vnode we are swapping to is the root vnode 940 * (i.e. we are swapping to the miniroot) then we want 941 * to make sure we don't overwrite it. do a statfs to 942 * find its size and skip over it. 943 */ 944 if (vp == rootvp) { 945 struct mount *mp; 946 struct statvfs *sp; 947 int rootblocks, rootpages; 948 949 mp = rootvnode->v_mount; 950 sp = &mp->mnt_stat; 951 rootblocks = sp->f_blocks * btodb(sp->f_frsize); 952 /* 953 * XXX: sp->f_blocks isn't the total number of 954 * blocks in the filesystem, it's the number of 955 * data blocks. so, our rootblocks almost 956 * definitely underestimates the total size 957 * of the filesystem - how badly depends on the 958 * details of the filesystem type. there isn't 959 * an obvious way to deal with this cleanly 960 * and perfectly, so for now we just pad our 961 * rootblocks estimate with an extra 5 percent. 962 */ 963 rootblocks += (rootblocks >> 5) + 964 (rootblocks >> 6) + 965 (rootblocks >> 7); 966 rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; 967 if (rootpages > size) 968 panic("swap_on: miniroot larger than swap?"); 969 970 if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { 971 panic("swap_on: unable to preserve miniroot"); 972 } 973 974 size -= rootpages; 975 printf("Preserved %d pages of miniroot ", rootpages); 976 printf("leaving %d pages of swap\n", size); 977 } 978 979 /* 980 * add a ref to vp to reflect usage as a swap device. 981 */ 982 vref(vp); 983 984 /* 985 * now add the new swapdev to the drum and enable. 986 */ 987 result = vmem_alloc(swapmap, npages, VM_BESTFIT | VM_SLEEP); 988 if (result == 0) 989 panic("swapdrum_add"); 990 /* 991 * If this is the first regular swap create the workqueue. 992 * => Protected by swap_syscall_lock. 993 */ 994 if (vp->v_type != VBLK) { 995 if (sw_reg_count++ == 0) { 996 KASSERT(sw_reg_workqueue == NULL); 997 if (workqueue_create(&sw_reg_workqueue, "swapiod", 998 sw_reg_iodone, NULL, PRIBIO, IPL_BIO, 0) != 0) 999 panic("%s: workqueue_create failed", __func__); 1000 } 1001 } 1002 1003 sdp->swd_drumoffset = (int)result; 1004 sdp->swd_drumsize = npages; 1005 sdp->swd_npages = size; 1006 mutex_enter(&uvm_swap_data_lock); 1007 sdp->swd_flags &= ~SWF_FAKE; /* going live */ 1008 sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); 1009 uvmexp.swpages += size; 1010 uvmexp.swpgavail += size; 1011 mutex_exit(&uvm_swap_data_lock); 1012 return (0); 1013 1014 /* 1015 * failure: clean up and return error. 1016 */ 1017 1018 bad: 1019 if (sdp->swd_blist) { 1020 blist_destroy(sdp->swd_blist); 1021 } 1022 if (vp != rootvp) { 1023 (void)VOP_CLOSE(vp, FREAD|FWRITE, l->l_cred); 1024 } 1025 return (error); 1026 } 1027 1028 /* 1029 * swap_off: stop swapping on swapdev 1030 * 1031 * => swap data should be locked, we will unlock. 1032 */ 1033 static int 1034 swap_off(struct lwp *l, struct swapdev *sdp) 1035 { 1036 int npages = sdp->swd_npages; 1037 int error = 0; 1038 1039 UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); 1040 UVMHIST_LOG(pdhist, " dev=%x, npages=%d", sdp->swd_dev,npages,0,0); 1041 1042 /* disable the swap area being removed */ 1043 sdp->swd_flags &= ~SWF_ENABLE; 1044 uvmexp.swpgavail -= npages; 1045 mutex_exit(&uvm_swap_data_lock); 1046 1047 /* 1048 * the idea is to find all the pages that are paged out to this 1049 * device, and page them all in. in uvm, swap-backed pageable 1050 * memory can take two forms: aobjs and anons. call the 1051 * swapoff hook for each subsystem to bring in pages. 1052 */ 1053 1054 if (uao_swap_off(sdp->swd_drumoffset, 1055 sdp->swd_drumoffset + sdp->swd_drumsize) || 1056 amap_swap_off(sdp->swd_drumoffset, 1057 sdp->swd_drumoffset + sdp->swd_drumsize)) { 1058 error = ENOMEM; 1059 } else if (sdp->swd_npginuse > sdp->swd_npgbad) { 1060 error = EBUSY; 1061 } 1062 1063 if (error) { 1064 mutex_enter(&uvm_swap_data_lock); 1065 sdp->swd_flags |= SWF_ENABLE; 1066 uvmexp.swpgavail += npages; 1067 mutex_exit(&uvm_swap_data_lock); 1068 1069 return error; 1070 } 1071 1072 /* 1073 * If this is the last regular swap destroy the workqueue. 1074 * => Protected by swap_syscall_lock. 1075 */ 1076 if (sdp->swd_vp->v_type != VBLK) { 1077 KASSERT(sw_reg_count > 0); 1078 KASSERT(sw_reg_workqueue != NULL); 1079 if (--sw_reg_count == 0) { 1080 workqueue_destroy(sw_reg_workqueue); 1081 sw_reg_workqueue = NULL; 1082 } 1083 } 1084 1085 /* 1086 * done with the vnode. 1087 * drop our ref on the vnode before calling VOP_CLOSE() 1088 * so that spec_close() can tell if this is the last close. 1089 */ 1090 vrele(sdp->swd_vp); 1091 if (sdp->swd_vp != rootvp) { 1092 (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, l->l_cred); 1093 } 1094 1095 mutex_enter(&uvm_swap_data_lock); 1096 uvmexp.swpages -= npages; 1097 uvmexp.swpginuse -= sdp->swd_npgbad; 1098 1099 if (swaplist_find(sdp->swd_vp, true) == NULL) 1100 panic("%s: swapdev not in list", __func__); 1101 swaplist_trim(); 1102 mutex_exit(&uvm_swap_data_lock); 1103 1104 /* 1105 * free all resources! 1106 */ 1107 vmem_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize); 1108 blist_destroy(sdp->swd_blist); 1109 bufq_free(sdp->swd_tab); 1110 free(sdp, M_VMSWAP); 1111 return (0); 1112 } 1113 1114 /* 1115 * /dev/drum interface and i/o functions 1116 */ 1117 1118 /* 1119 * swstrategy: perform I/O on the drum 1120 * 1121 * => we must map the i/o request from the drum to the correct swapdev. 1122 */ 1123 static void 1124 swstrategy(struct buf *bp) 1125 { 1126 struct swapdev *sdp; 1127 struct vnode *vp; 1128 int pageno, bn; 1129 UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); 1130 1131 /* 1132 * convert block number to swapdev. note that swapdev can't 1133 * be yanked out from under us because we are holding resources 1134 * in it (i.e. the blocks we are doing I/O on). 1135 */ 1136 pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; 1137 mutex_enter(&uvm_swap_data_lock); 1138 sdp = swapdrum_getsdp(pageno); 1139 mutex_exit(&uvm_swap_data_lock); 1140 if (sdp == NULL) { 1141 bp->b_error = EINVAL; 1142 biodone(bp); 1143 UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); 1144 return; 1145 } 1146 1147 /* 1148 * convert drum page number to block number on this swapdev. 1149 */ 1150 1151 pageno -= sdp->swd_drumoffset; /* page # on swapdev */ 1152 bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ 1153 1154 UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld", 1155 ((bp->b_flags & B_READ) == 0) ? "write" : "read", 1156 sdp->swd_drumoffset, bn, bp->b_bcount); 1157 1158 /* 1159 * for block devices we finish up here. 1160 * for regular files we have to do more work which we delegate 1161 * to sw_reg_strategy(). 1162 */ 1163 1164 vp = sdp->swd_vp; /* swapdev vnode pointer */ 1165 switch (vp->v_type) { 1166 default: 1167 panic("%s: vnode type 0x%x", __func__, vp->v_type); 1168 1169 case VBLK: 1170 1171 /* 1172 * must convert "bp" from an I/O on /dev/drum to an I/O 1173 * on the swapdev (sdp). 1174 */ 1175 bp->b_blkno = bn; /* swapdev block number */ 1176 bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ 1177 1178 /* 1179 * if we are doing a write, we have to redirect the i/o on 1180 * drum's v_numoutput counter to the swapdevs. 1181 */ 1182 if ((bp->b_flags & B_READ) == 0) { 1183 mutex_enter(bp->b_objlock); 1184 vwakeup(bp); /* kills one 'v_numoutput' on drum */ 1185 mutex_exit(bp->b_objlock); 1186 mutex_enter(&vp->v_interlock); 1187 vp->v_numoutput++; /* put it on swapdev */ 1188 mutex_exit(&vp->v_interlock); 1189 } 1190 1191 /* 1192 * finally plug in swapdev vnode and start I/O 1193 */ 1194 bp->b_vp = vp; 1195 bp->b_objlock = &vp->v_interlock; 1196 VOP_STRATEGY(vp, bp); 1197 return; 1198 1199 case VREG: 1200 /* 1201 * delegate to sw_reg_strategy function. 1202 */ 1203 sw_reg_strategy(sdp, bp, bn); 1204 return; 1205 } 1206 /* NOTREACHED */ 1207 } 1208 1209 /* 1210 * swread: the read function for the drum (just a call to physio) 1211 */ 1212 /*ARGSUSED*/ 1213 static int 1214 swread(dev_t dev, struct uio *uio, int ioflag) 1215 { 1216 UVMHIST_FUNC("swread"); UVMHIST_CALLED(pdhist); 1217 1218 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1219 return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); 1220 } 1221 1222 /* 1223 * swwrite: the write function for the drum (just a call to physio) 1224 */ 1225 /*ARGSUSED*/ 1226 static int 1227 swwrite(dev_t dev, struct uio *uio, int ioflag) 1228 { 1229 UVMHIST_FUNC("swwrite"); UVMHIST_CALLED(pdhist); 1230 1231 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1232 return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); 1233 } 1234 1235 const struct bdevsw swap_bdevsw = { 1236 nullopen, nullclose, swstrategy, noioctl, nodump, nosize, D_OTHER, 1237 }; 1238 1239 const struct cdevsw swap_cdevsw = { 1240 nullopen, nullclose, swread, swwrite, noioctl, 1241 nostop, notty, nopoll, nommap, nokqfilter, D_OTHER, 1242 }; 1243 1244 /* 1245 * sw_reg_strategy: handle swap i/o to regular files 1246 */ 1247 static void 1248 sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) 1249 { 1250 struct vnode *vp; 1251 struct vndxfer *vnx; 1252 daddr_t nbn; 1253 char *addr; 1254 off_t byteoff; 1255 int s, off, nra, error, sz, resid; 1256 UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); 1257 1258 /* 1259 * allocate a vndxfer head for this transfer and point it to 1260 * our buffer. 1261 */ 1262 vnx = pool_get(&vndxfer_pool, PR_WAITOK); 1263 vnx->vx_flags = VX_BUSY; 1264 vnx->vx_error = 0; 1265 vnx->vx_pending = 0; 1266 vnx->vx_bp = bp; 1267 vnx->vx_sdp = sdp; 1268 1269 /* 1270 * setup for main loop where we read filesystem blocks into 1271 * our buffer. 1272 */ 1273 error = 0; 1274 bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ 1275 addr = bp->b_data; /* current position in buffer */ 1276 byteoff = dbtob((uint64_t)bn); 1277 1278 for (resid = bp->b_resid; resid; resid -= sz) { 1279 struct vndbuf *nbp; 1280 1281 /* 1282 * translate byteoffset into block number. return values: 1283 * vp = vnode of underlying device 1284 * nbn = new block number (on underlying vnode dev) 1285 * nra = num blocks we can read-ahead (excludes requested 1286 * block) 1287 */ 1288 nra = 0; 1289 error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, 1290 &vp, &nbn, &nra); 1291 1292 if (error == 0 && nbn == (daddr_t)-1) { 1293 /* 1294 * this used to just set error, but that doesn't 1295 * do the right thing. Instead, it causes random 1296 * memory errors. The panic() should remain until 1297 * this condition doesn't destabilize the system. 1298 */ 1299 #if 1 1300 panic("%s: swap to sparse file", __func__); 1301 #else 1302 error = EIO; /* failure */ 1303 #endif 1304 } 1305 1306 /* 1307 * punt if there was an error or a hole in the file. 1308 * we must wait for any i/o ops we have already started 1309 * to finish before returning. 1310 * 1311 * XXX we could deal with holes here but it would be 1312 * a hassle (in the write case). 1313 */ 1314 if (error) { 1315 s = splbio(); 1316 vnx->vx_error = error; /* pass error up */ 1317 goto out; 1318 } 1319 1320 /* 1321 * compute the size ("sz") of this transfer (in bytes). 1322 */ 1323 off = byteoff % sdp->swd_bsize; 1324 sz = (1 + nra) * sdp->swd_bsize - off; 1325 if (sz > resid) 1326 sz = resid; 1327 1328 UVMHIST_LOG(pdhist, "sw_reg_strategy: " 1329 "vp %p/%p offset 0x%x/0x%x", 1330 sdp->swd_vp, vp, byteoff, nbn); 1331 1332 /* 1333 * now get a buf structure. note that the vb_buf is 1334 * at the front of the nbp structure so that you can 1335 * cast pointers between the two structure easily. 1336 */ 1337 nbp = pool_get(&vndbuf_pool, PR_WAITOK); 1338 buf_init(&nbp->vb_buf); 1339 nbp->vb_buf.b_flags = bp->b_flags; 1340 nbp->vb_buf.b_cflags = bp->b_cflags; 1341 nbp->vb_buf.b_oflags = bp->b_oflags; 1342 nbp->vb_buf.b_bcount = sz; 1343 nbp->vb_buf.b_bufsize = sz; 1344 nbp->vb_buf.b_error = 0; 1345 nbp->vb_buf.b_data = addr; 1346 nbp->vb_buf.b_lblkno = 0; 1347 nbp->vb_buf.b_blkno = nbn + btodb(off); 1348 nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; 1349 nbp->vb_buf.b_iodone = sw_reg_biodone; 1350 nbp->vb_buf.b_vp = vp; 1351 nbp->vb_buf.b_objlock = &vp->v_interlock; 1352 if (vp->v_type == VBLK) { 1353 nbp->vb_buf.b_dev = vp->v_rdev; 1354 } 1355 1356 nbp->vb_xfer = vnx; /* patch it back in to vnx */ 1357 1358 /* 1359 * Just sort by block number 1360 */ 1361 s = splbio(); 1362 if (vnx->vx_error != 0) { 1363 buf_destroy(&nbp->vb_buf); 1364 pool_put(&vndbuf_pool, nbp); 1365 goto out; 1366 } 1367 vnx->vx_pending++; 1368 1369 /* sort it in and start I/O if we are not over our limit */ 1370 /* XXXAD locking */ 1371 bufq_put(sdp->swd_tab, &nbp->vb_buf); 1372 sw_reg_start(sdp); 1373 splx(s); 1374 1375 /* 1376 * advance to the next I/O 1377 */ 1378 byteoff += sz; 1379 addr += sz; 1380 } 1381 1382 s = splbio(); 1383 1384 out: /* Arrive here at splbio */ 1385 vnx->vx_flags &= ~VX_BUSY; 1386 if (vnx->vx_pending == 0) { 1387 error = vnx->vx_error; 1388 pool_put(&vndxfer_pool, vnx); 1389 bp->b_error = error; 1390 biodone(bp); 1391 } 1392 splx(s); 1393 } 1394 1395 /* 1396 * sw_reg_start: start an I/O request on the requested swapdev 1397 * 1398 * => reqs are sorted by b_rawblkno (above) 1399 */ 1400 static void 1401 sw_reg_start(struct swapdev *sdp) 1402 { 1403 struct buf *bp; 1404 struct vnode *vp; 1405 UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); 1406 1407 /* recursion control */ 1408 if ((sdp->swd_flags & SWF_BUSY) != 0) 1409 return; 1410 1411 sdp->swd_flags |= SWF_BUSY; 1412 1413 while (sdp->swd_active < sdp->swd_maxactive) { 1414 bp = bufq_get(sdp->swd_tab); 1415 if (bp == NULL) 1416 break; 1417 sdp->swd_active++; 1418 1419 UVMHIST_LOG(pdhist, 1420 "sw_reg_start: bp %p vp %p blkno %p cnt %lx", 1421 bp, bp->b_vp, bp->b_blkno, bp->b_bcount); 1422 vp = bp->b_vp; 1423 KASSERT(bp->b_objlock == &vp->v_interlock); 1424 if ((bp->b_flags & B_READ) == 0) { 1425 mutex_enter(&vp->v_interlock); 1426 vp->v_numoutput++; 1427 mutex_exit(&vp->v_interlock); 1428 } 1429 VOP_STRATEGY(vp, bp); 1430 } 1431 sdp->swd_flags &= ~SWF_BUSY; 1432 } 1433 1434 /* 1435 * sw_reg_biodone: one of our i/o's has completed 1436 */ 1437 static void 1438 sw_reg_biodone(struct buf *bp) 1439 { 1440 workqueue_enqueue(sw_reg_workqueue, &bp->b_work, NULL); 1441 } 1442 1443 /* 1444 * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup 1445 * 1446 * => note that we can recover the vndbuf struct by casting the buf ptr 1447 */ 1448 static void 1449 sw_reg_iodone(struct work *wk, void *dummy) 1450 { 1451 struct vndbuf *vbp = (void *)wk; 1452 struct vndxfer *vnx = vbp->vb_xfer; 1453 struct buf *pbp = vnx->vx_bp; /* parent buffer */ 1454 struct swapdev *sdp = vnx->vx_sdp; 1455 int s, resid, error; 1456 KASSERT(&vbp->vb_buf.b_work == wk); 1457 UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); 1458 1459 UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p", 1460 vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); 1461 UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", 1462 vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); 1463 1464 /* 1465 * protect vbp at splbio and update. 1466 */ 1467 1468 s = splbio(); 1469 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 1470 pbp->b_resid -= resid; 1471 vnx->vx_pending--; 1472 1473 if (vbp->vb_buf.b_error != 0) { 1474 /* pass error upward */ 1475 error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; 1476 UVMHIST_LOG(pdhist, " got error=%d !", error, 0, 0, 0); 1477 vnx->vx_error = error; 1478 } 1479 1480 /* 1481 * kill vbp structure 1482 */ 1483 buf_destroy(&vbp->vb_buf); 1484 pool_put(&vndbuf_pool, vbp); 1485 1486 /* 1487 * wrap up this transaction if it has run to completion or, in 1488 * case of an error, when all auxiliary buffers have returned. 1489 */ 1490 if (vnx->vx_error != 0) { 1491 /* pass error upward */ 1492 error = vnx->vx_error; 1493 if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { 1494 pbp->b_error = error; 1495 biodone(pbp); 1496 pool_put(&vndxfer_pool, vnx); 1497 } 1498 } else if (pbp->b_resid == 0) { 1499 KASSERT(vnx->vx_pending == 0); 1500 if ((vnx->vx_flags & VX_BUSY) == 0) { 1501 UVMHIST_LOG(pdhist, " iodone error=%d !", 1502 pbp, vnx->vx_error, 0, 0); 1503 biodone(pbp); 1504 pool_put(&vndxfer_pool, vnx); 1505 } 1506 } 1507 1508 /* 1509 * done! start next swapdev I/O if one is pending 1510 */ 1511 sdp->swd_active--; 1512 sw_reg_start(sdp); 1513 splx(s); 1514 } 1515 1516 1517 /* 1518 * uvm_swap_alloc: allocate space on swap 1519 * 1520 * => allocation is done "round robin" down the priority list, as we 1521 * allocate in a priority we "rotate" the circle queue. 1522 * => space can be freed with uvm_swap_free 1523 * => we return the page slot number in /dev/drum (0 == invalid slot) 1524 * => we lock uvm_swap_data_lock 1525 * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM 1526 */ 1527 int 1528 uvm_swap_alloc(int *nslots /* IN/OUT */, bool lessok) 1529 { 1530 struct swapdev *sdp; 1531 struct swappri *spp; 1532 UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); 1533 1534 /* 1535 * no swap devices configured yet? definite failure. 1536 */ 1537 if (uvmexp.nswapdev < 1) 1538 return 0; 1539 1540 /* 1541 * lock data lock, convert slots into blocks, and enter loop 1542 */ 1543 mutex_enter(&uvm_swap_data_lock); 1544 1545 ReTry: /* XXXMRG */ 1546 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 1547 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 1548 uint64_t result; 1549 1550 /* if it's not enabled, then we can't swap from it */ 1551 if ((sdp->swd_flags & SWF_ENABLE) == 0) 1552 continue; 1553 if (sdp->swd_npginuse + *nslots > sdp->swd_npages) 1554 continue; 1555 result = blist_alloc(sdp->swd_blist, *nslots); 1556 if (result == BLIST_NONE) { 1557 continue; 1558 } 1559 KASSERT(result < sdp->swd_drumsize); 1560 1561 /* 1562 * successful allocation! now rotate the circleq. 1563 */ 1564 CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); 1565 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 1566 sdp->swd_npginuse += *nslots; 1567 uvmexp.swpginuse += *nslots; 1568 mutex_exit(&uvm_swap_data_lock); 1569 /* done! return drum slot number */ 1570 UVMHIST_LOG(pdhist, 1571 "success! returning %d slots starting at %d", 1572 *nslots, result + sdp->swd_drumoffset, 0, 0); 1573 return (result + sdp->swd_drumoffset); 1574 } 1575 } 1576 1577 /* XXXMRG: BEGIN HACK */ 1578 if (*nslots > 1 && lessok) { 1579 *nslots = 1; 1580 /* XXXMRG: ugh! blist should support this for us */ 1581 goto ReTry; 1582 } 1583 /* XXXMRG: END HACK */ 1584 1585 mutex_exit(&uvm_swap_data_lock); 1586 return 0; 1587 } 1588 1589 /* 1590 * uvm_swapisfull: return true if most of available swap is allocated 1591 * and in use. we don't count some small portion as it may be inaccessible 1592 * to us at any given moment, for example if there is lock contention or if 1593 * pages are busy. 1594 */ 1595 bool 1596 uvm_swapisfull(void) 1597 { 1598 int swpgonly; 1599 bool rv; 1600 1601 mutex_enter(&uvm_swap_data_lock); 1602 KASSERT(uvmexp.swpgonly <= uvmexp.swpages); 1603 swpgonly = (int)((uint64_t)uvmexp.swpgonly * 100 / 1604 uvm_swapisfull_factor); 1605 rv = (swpgonly >= uvmexp.swpgavail); 1606 mutex_exit(&uvm_swap_data_lock); 1607 1608 return (rv); 1609 } 1610 1611 /* 1612 * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors 1613 * 1614 * => we lock uvm_swap_data_lock 1615 */ 1616 void 1617 uvm_swap_markbad(int startslot, int nslots) 1618 { 1619 struct swapdev *sdp; 1620 UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); 1621 1622 mutex_enter(&uvm_swap_data_lock); 1623 sdp = swapdrum_getsdp(startslot); 1624 KASSERT(sdp != NULL); 1625 1626 /* 1627 * we just keep track of how many pages have been marked bad 1628 * in this device, to make everything add up in swap_off(). 1629 * we assume here that the range of slots will all be within 1630 * one swap device. 1631 */ 1632 1633 KASSERT(uvmexp.swpgonly >= nslots); 1634 uvmexp.swpgonly -= nslots; 1635 sdp->swd_npgbad += nslots; 1636 UVMHIST_LOG(pdhist, "now %d bad", sdp->swd_npgbad, 0,0,0); 1637 mutex_exit(&uvm_swap_data_lock); 1638 } 1639 1640 /* 1641 * uvm_swap_free: free swap slots 1642 * 1643 * => this can be all or part of an allocation made by uvm_swap_alloc 1644 * => we lock uvm_swap_data_lock 1645 */ 1646 void 1647 uvm_swap_free(int startslot, int nslots) 1648 { 1649 struct swapdev *sdp; 1650 UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); 1651 1652 UVMHIST_LOG(pdhist, "freeing %d slots starting at %d", nslots, 1653 startslot, 0, 0); 1654 1655 /* 1656 * ignore attempts to free the "bad" slot. 1657 */ 1658 1659 if (startslot == SWSLOT_BAD) { 1660 return; 1661 } 1662 1663 /* 1664 * convert drum slot offset back to sdp, free the blocks 1665 * in the extent, and return. must hold pri lock to do 1666 * lookup and access the extent. 1667 */ 1668 1669 mutex_enter(&uvm_swap_data_lock); 1670 sdp = swapdrum_getsdp(startslot); 1671 KASSERT(uvmexp.nswapdev >= 1); 1672 KASSERT(sdp != NULL); 1673 KASSERT(sdp->swd_npginuse >= nslots); 1674 blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); 1675 sdp->swd_npginuse -= nslots; 1676 uvmexp.swpginuse -= nslots; 1677 mutex_exit(&uvm_swap_data_lock); 1678 } 1679 1680 /* 1681 * uvm_swap_put: put any number of pages into a contig place on swap 1682 * 1683 * => can be sync or async 1684 */ 1685 1686 int 1687 uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) 1688 { 1689 int error; 1690 1691 error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | 1692 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1693 return error; 1694 } 1695 1696 /* 1697 * uvm_swap_get: get a single page from swap 1698 * 1699 * => usually a sync op (from fault) 1700 */ 1701 1702 int 1703 uvm_swap_get(struct vm_page *page, int swslot, int flags) 1704 { 1705 int error; 1706 1707 uvmexp.nswget++; 1708 KASSERT(flags & PGO_SYNCIO); 1709 if (swslot == SWSLOT_BAD) { 1710 return EIO; 1711 } 1712 1713 error = uvm_swap_io(&page, swslot, 1, B_READ | 1714 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1715 if (error == 0) { 1716 1717 /* 1718 * this page is no longer only in swap. 1719 */ 1720 1721 mutex_enter(&uvm_swap_data_lock); 1722 KASSERT(uvmexp.swpgonly > 0); 1723 uvmexp.swpgonly--; 1724 mutex_exit(&uvm_swap_data_lock); 1725 } 1726 return error; 1727 } 1728 1729 /* 1730 * uvm_swap_io: do an i/o operation to swap 1731 */ 1732 1733 static int 1734 uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) 1735 { 1736 daddr_t startblk; 1737 struct buf *bp; 1738 vaddr_t kva; 1739 int error, mapinflags; 1740 bool write, async; 1741 UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); 1742 1743 UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d", 1744 startslot, npages, flags, 0); 1745 1746 write = (flags & B_READ) == 0; 1747 async = (flags & B_ASYNC) != 0; 1748 1749 /* 1750 * allocate a buf for the i/o. 1751 */ 1752 1753 KASSERT(curlwp != uvm.pagedaemon_lwp || (write && async)); 1754 bp = getiobuf(swapdev_vp, curlwp != uvm.pagedaemon_lwp); 1755 if (bp == NULL) { 1756 uvm_aio_aiodone_pages(pps, npages, true, ENOMEM); 1757 return ENOMEM; 1758 } 1759 1760 /* 1761 * convert starting drum slot to block number 1762 */ 1763 1764 startblk = btodb((uint64_t)startslot << PAGE_SHIFT); 1765 1766 /* 1767 * first, map the pages into the kernel. 1768 */ 1769 1770 mapinflags = !write ? 1771 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : 1772 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; 1773 kva = uvm_pagermapin(pps, npages, mapinflags); 1774 1775 /* 1776 * fill in the bp/sbp. we currently route our i/o through 1777 * /dev/drum's vnode [swapdev_vp]. 1778 */ 1779 1780 bp->b_cflags = BC_BUSY | BC_NOCACHE; 1781 bp->b_flags = (flags & (B_READ|B_ASYNC)); 1782 bp->b_proc = &proc0; /* XXX */ 1783 bp->b_vnbufs.le_next = NOLIST; 1784 bp->b_data = (void *)kva; 1785 bp->b_blkno = startblk; 1786 bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; 1787 1788 /* 1789 * bump v_numoutput (counter of number of active outputs). 1790 */ 1791 1792 if (write) { 1793 mutex_enter(&swapdev_vp->v_interlock); 1794 swapdev_vp->v_numoutput++; 1795 mutex_exit(&swapdev_vp->v_interlock); 1796 } 1797 1798 /* 1799 * for async ops we must set up the iodone handler. 1800 */ 1801 1802 if (async) { 1803 bp->b_iodone = uvm_aio_biodone; 1804 UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); 1805 if (curlwp == uvm.pagedaemon_lwp) 1806 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1807 else 1808 BIO_SETPRIO(bp, BPRIO_TIMELIMITED); 1809 } else { 1810 bp->b_iodone = NULL; 1811 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1812 } 1813 UVMHIST_LOG(pdhist, 1814 "about to start io: data = %p blkno = 0x%x, bcount = %ld", 1815 bp->b_data, bp->b_blkno, bp->b_bcount, 0); 1816 1817 /* 1818 * now we start the I/O, and if async, return. 1819 */ 1820 1821 VOP_STRATEGY(swapdev_vp, bp); 1822 if (async) 1823 return 0; 1824 1825 /* 1826 * must be sync i/o. wait for it to finish 1827 */ 1828 1829 error = biowait(bp); 1830 1831 /* 1832 * kill the pager mapping 1833 */ 1834 1835 uvm_pagermapout(kva, npages); 1836 1837 /* 1838 * now dispose of the buf and we're done. 1839 */ 1840 1841 if (write) { 1842 mutex_enter(&swapdev_vp->v_interlock); 1843 vwakeup(bp); 1844 mutex_exit(&swapdev_vp->v_interlock); 1845 } 1846 putiobuf(bp); 1847 UVMHIST_LOG(pdhist, "<- done (sync) error=%d", error, 0, 0, 0); 1848 1849 return (error); 1850 } 1851