1 /* $NetBSD: uvm_swap.c,v 1.102 2006/06/13 01:59:59 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1995, 1996, 1997 Matthew R. Green 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 23 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 24 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 25 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 26 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * from: NetBSD: vm_swap.c,v 1.52 1997/12/02 13:47:37 pk Exp 31 * from: Id: uvm_swap.c,v 1.1.2.42 1998/02/02 20:38:06 chuck Exp 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: uvm_swap.c,v 1.102 2006/06/13 01:59:59 christos Exp $"); 36 37 #include "fs_nfs.h" 38 #include "opt_uvmhist.h" 39 #include "opt_compat_netbsd.h" 40 #include "opt_ddb.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/buf.h> 45 #include <sys/bufq.h> 46 #include <sys/conf.h> 47 #include <sys/proc.h> 48 #include <sys/namei.h> 49 #include <sys/disklabel.h> 50 #include <sys/errno.h> 51 #include <sys/kernel.h> 52 #include <sys/malloc.h> 53 #include <sys/vnode.h> 54 #include <sys/file.h> 55 #include <sys/extent.h> 56 #include <sys/blist.h> 57 #include <sys/mount.h> 58 #include <sys/pool.h> 59 #include <sys/sa.h> 60 #include <sys/syscallargs.h> 61 #include <sys/swap.h> 62 #include <sys/kauth.h> 63 64 #include <uvm/uvm.h> 65 66 #include <miscfs/specfs/specdev.h> 67 68 /* 69 * uvm_swap.c: manage configuration and i/o to swap space. 70 */ 71 72 /* 73 * swap space is managed in the following way: 74 * 75 * each swap partition or file is described by a "swapdev" structure. 76 * each "swapdev" structure contains a "swapent" structure which contains 77 * information that is passed up to the user (via system calls). 78 * 79 * each swap partition is assigned a "priority" (int) which controls 80 * swap parition usage. 81 * 82 * the system maintains a global data structure describing all swap 83 * partitions/files. there is a sorted LIST of "swappri" structures 84 * which describe "swapdev"'s at that priority. this LIST is headed 85 * by the "swap_priority" global var. each "swappri" contains a 86 * CIRCLEQ of "swapdev" structures at that priority. 87 * 88 * locking: 89 * - swap_syscall_lock (sleep lock): this lock serializes the swapctl 90 * system call and prevents the swap priority list from changing 91 * while we are in the middle of a system call (e.g. SWAP_STATS). 92 * - uvm.swap_data_lock (simple_lock): this lock protects all swap data 93 * structures including the priority list, the swapdev structures, 94 * and the swapmap extent. 95 * 96 * each swap device has the following info: 97 * - swap device in use (could be disabled, preventing future use) 98 * - swap enabled (allows new allocations on swap) 99 * - map info in /dev/drum 100 * - vnode pointer 101 * for swap files only: 102 * - block size 103 * - max byte count in buffer 104 * - buffer 105 * 106 * userland controls and configures swap with the swapctl(2) system call. 107 * the sys_swapctl performs the following operations: 108 * [1] SWAP_NSWAP: returns the number of swap devices currently configured 109 * [2] SWAP_STATS: given a pointer to an array of swapent structures 110 * (passed in via "arg") of a size passed in via "misc" ... we load 111 * the current swap config into the array. The actual work is done 112 * in the uvm_swap_stats(9) function. 113 * [3] SWAP_ON: given a pathname in arg (could be device or file) and a 114 * priority in "misc", start swapping on it. 115 * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device 116 * [5] SWAP_CTL: changes the priority of a swap device (new priority in 117 * "misc") 118 */ 119 120 /* 121 * swapdev: describes a single swap partition/file 122 * 123 * note the following should be true: 124 * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] 125 * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] 126 */ 127 struct swapdev { 128 struct oswapent swd_ose; 129 #define swd_dev swd_ose.ose_dev /* device id */ 130 #define swd_flags swd_ose.ose_flags /* flags:inuse/enable/fake */ 131 #define swd_priority swd_ose.ose_priority /* our priority */ 132 /* also: swd_ose.ose_nblks, swd_ose.ose_inuse */ 133 char *swd_path; /* saved pathname of device */ 134 int swd_pathlen; /* length of pathname */ 135 int swd_npages; /* #pages we can use */ 136 int swd_npginuse; /* #pages in use */ 137 int swd_npgbad; /* #pages bad */ 138 int swd_drumoffset; /* page0 offset in drum */ 139 int swd_drumsize; /* #pages in drum */ 140 blist_t swd_blist; /* blist for this swapdev */ 141 struct vnode *swd_vp; /* backing vnode */ 142 CIRCLEQ_ENTRY(swapdev) swd_next; /* priority circleq */ 143 144 int swd_bsize; /* blocksize (bytes) */ 145 int swd_maxactive; /* max active i/o reqs */ 146 struct bufq_state *swd_tab; /* buffer list */ 147 int swd_active; /* number of active buffers */ 148 }; 149 150 /* 151 * swap device priority entry; the list is kept sorted on `spi_priority'. 152 */ 153 struct swappri { 154 int spi_priority; /* priority */ 155 CIRCLEQ_HEAD(spi_swapdev, swapdev) spi_swapdev; 156 /* circleq of swapdevs at this priority */ 157 LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ 158 }; 159 160 /* 161 * The following two structures are used to keep track of data transfers 162 * on swap devices associated with regular files. 163 * NOTE: this code is more or less a copy of vnd.c; we use the same 164 * structure names here to ease porting.. 165 */ 166 struct vndxfer { 167 struct buf *vx_bp; /* Pointer to parent buffer */ 168 struct swapdev *vx_sdp; 169 int vx_error; 170 int vx_pending; /* # of pending aux buffers */ 171 int vx_flags; 172 #define VX_BUSY 1 173 #define VX_DEAD 2 174 }; 175 176 struct vndbuf { 177 struct buf vb_buf; 178 struct vndxfer *vb_xfer; 179 }; 180 181 182 /* 183 * We keep a of pool vndbuf's and vndxfer structures. 184 */ 185 POOL_INIT(vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", NULL); 186 POOL_INIT(vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", NULL); 187 188 #define getvndxfer(vnx) do { \ 189 int sp = splbio(); \ 190 vnx = pool_get(&vndxfer_pool, PR_WAITOK); \ 191 splx(sp); \ 192 } while (/*CONSTCOND*/ 0) 193 194 #define putvndxfer(vnx) { \ 195 pool_put(&vndxfer_pool, (void *)(vnx)); \ 196 } 197 198 #define getvndbuf(vbp) do { \ 199 int sp = splbio(); \ 200 vbp = pool_get(&vndbuf_pool, PR_WAITOK); \ 201 splx(sp); \ 202 } while (/*CONSTCOND*/ 0) 203 204 #define putvndbuf(vbp) { \ 205 pool_put(&vndbuf_pool, (void *)(vbp)); \ 206 } 207 208 /* 209 * local variables 210 */ 211 static struct extent *swapmap; /* controls the mapping of /dev/drum */ 212 213 MALLOC_DEFINE(M_VMSWAP, "VM swap", "VM swap structures"); 214 215 /* list of all active swap devices [by priority] */ 216 LIST_HEAD(swap_priority, swappri); 217 static struct swap_priority swap_priority; 218 219 /* locks */ 220 static struct lock swap_syscall_lock; 221 222 /* 223 * prototypes 224 */ 225 static struct swapdev *swapdrum_getsdp(int); 226 227 static struct swapdev *swaplist_find(struct vnode *, int); 228 static void swaplist_insert(struct swapdev *, 229 struct swappri *, int); 230 static void swaplist_trim(void); 231 232 static int swap_on(struct lwp *, struct swapdev *); 233 static int swap_off(struct lwp *, struct swapdev *); 234 235 static void uvm_swap_stats_locked(int, struct swapent *, int, register_t *); 236 237 static void sw_reg_strategy(struct swapdev *, struct buf *, int); 238 static void sw_reg_iodone(struct buf *); 239 static void sw_reg_start(struct swapdev *); 240 241 static int uvm_swap_io(struct vm_page **, int, int, int); 242 243 /* 244 * uvm_swap_init: init the swap system data structures and locks 245 * 246 * => called at boot time from init_main.c after the filesystems 247 * are brought up (which happens after uvm_init()) 248 */ 249 void 250 uvm_swap_init(void) 251 { 252 UVMHIST_FUNC("uvm_swap_init"); 253 254 UVMHIST_CALLED(pdhist); 255 /* 256 * first, init the swap list, its counter, and its lock. 257 * then get a handle on the vnode for /dev/drum by using 258 * the its dev_t number ("swapdev", from MD conf.c). 259 */ 260 261 LIST_INIT(&swap_priority); 262 uvmexp.nswapdev = 0; 263 lockinit(&swap_syscall_lock, PVM, "swapsys", 0, 0); 264 simple_lock_init(&uvm.swap_data_lock); 265 266 if (bdevvp(swapdev, &swapdev_vp)) 267 panic("uvm_swap_init: can't get vnode for swap device"); 268 269 /* 270 * create swap block resource map to map /dev/drum. the range 271 * from 1 to INT_MAX allows 2 gigablocks of swap space. note 272 * that block 0 is reserved (used to indicate an allocation 273 * failure, or no allocation). 274 */ 275 swapmap = extent_create("swapmap", 1, INT_MAX, 276 M_VMSWAP, 0, 0, EX_NOWAIT); 277 if (swapmap == 0) 278 panic("uvm_swap_init: extent_create failed"); 279 280 /* 281 * done! 282 */ 283 UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); 284 } 285 286 /* 287 * swaplist functions: functions that operate on the list of swap 288 * devices on the system. 289 */ 290 291 /* 292 * swaplist_insert: insert swap device "sdp" into the global list 293 * 294 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 295 * => caller must provide a newly malloc'd swappri structure (we will 296 * FREE it if we don't need it... this it to prevent malloc blocking 297 * here while adding swap) 298 */ 299 static void 300 swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) 301 { 302 struct swappri *spp, *pspp; 303 UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); 304 305 /* 306 * find entry at or after which to insert the new device. 307 */ 308 pspp = NULL; 309 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 310 if (priority <= spp->spi_priority) 311 break; 312 pspp = spp; 313 } 314 315 /* 316 * new priority? 317 */ 318 if (spp == NULL || spp->spi_priority != priority) { 319 spp = newspp; /* use newspp! */ 320 UVMHIST_LOG(pdhist, "created new swappri = %d", 321 priority, 0, 0, 0); 322 323 spp->spi_priority = priority; 324 CIRCLEQ_INIT(&spp->spi_swapdev); 325 326 if (pspp) 327 LIST_INSERT_AFTER(pspp, spp, spi_swappri); 328 else 329 LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); 330 } else { 331 /* we don't need a new priority structure, free it */ 332 FREE(newspp, M_VMSWAP); 333 } 334 335 /* 336 * priority found (or created). now insert on the priority's 337 * circleq list and bump the total number of swapdevs. 338 */ 339 sdp->swd_priority = priority; 340 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 341 uvmexp.nswapdev++; 342 } 343 344 /* 345 * swaplist_find: find and optionally remove a swap device from the 346 * global list. 347 * 348 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 349 * => we return the swapdev we found (and removed) 350 */ 351 static struct swapdev * 352 swaplist_find(struct vnode *vp, boolean_t remove) 353 { 354 struct swapdev *sdp; 355 struct swappri *spp; 356 357 /* 358 * search the lists for the requested vp 359 */ 360 361 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 362 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 363 if (sdp->swd_vp == vp) { 364 if (remove) { 365 CIRCLEQ_REMOVE(&spp->spi_swapdev, 366 sdp, swd_next); 367 uvmexp.nswapdev--; 368 } 369 return(sdp); 370 } 371 } 372 } 373 return (NULL); 374 } 375 376 377 /* 378 * swaplist_trim: scan priority list for empty priority entries and kill 379 * them. 380 * 381 * => caller must hold both swap_syscall_lock and uvm.swap_data_lock 382 */ 383 static void 384 swaplist_trim(void) 385 { 386 struct swappri *spp, *nextspp; 387 388 for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = nextspp) { 389 nextspp = LIST_NEXT(spp, spi_swappri); 390 if (CIRCLEQ_FIRST(&spp->spi_swapdev) != 391 (void *)&spp->spi_swapdev) 392 continue; 393 LIST_REMOVE(spp, spi_swappri); 394 free(spp, M_VMSWAP); 395 } 396 } 397 398 /* 399 * swapdrum_getsdp: given a page offset in /dev/drum, convert it back 400 * to the "swapdev" that maps that section of the drum. 401 * 402 * => each swapdev takes one big contig chunk of the drum 403 * => caller must hold uvm.swap_data_lock 404 */ 405 static struct swapdev * 406 swapdrum_getsdp(int pgno) 407 { 408 struct swapdev *sdp; 409 struct swappri *spp; 410 411 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 412 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 413 if (sdp->swd_flags & SWF_FAKE) 414 continue; 415 if (pgno >= sdp->swd_drumoffset && 416 pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { 417 return sdp; 418 } 419 } 420 } 421 return NULL; 422 } 423 424 425 /* 426 * sys_swapctl: main entry point for swapctl(2) system call 427 * [with two helper functions: swap_on and swap_off] 428 */ 429 int 430 sys_swapctl(struct lwp *l, void *v, register_t *retval) 431 { 432 struct sys_swapctl_args /* { 433 syscallarg(int) cmd; 434 syscallarg(void *) arg; 435 syscallarg(int) misc; 436 } */ *uap = (struct sys_swapctl_args *)v; 437 struct proc *p = l->l_proc; 438 struct vnode *vp; 439 struct nameidata nd; 440 struct swappri *spp; 441 struct swapdev *sdp; 442 struct swapent *sep; 443 #define SWAP_PATH_MAX (PATH_MAX + 1) 444 char *userpath; 445 size_t len; 446 int error, misc; 447 int priority; 448 UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); 449 450 misc = SCARG(uap, misc); 451 452 /* 453 * ensure serialized syscall access by grabbing the swap_syscall_lock 454 */ 455 lockmgr(&swap_syscall_lock, LK_EXCLUSIVE, NULL); 456 457 userpath = malloc(SWAP_PATH_MAX, M_TEMP, M_WAITOK); 458 /* 459 * we handle the non-priv NSWAP and STATS request first. 460 * 461 * SWAP_NSWAP: return number of config'd swap devices 462 * [can also be obtained with uvmexp sysctl] 463 */ 464 if (SCARG(uap, cmd) == SWAP_NSWAP) { 465 UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d", uvmexp.nswapdev, 466 0, 0, 0); 467 *retval = uvmexp.nswapdev; 468 error = 0; 469 goto out; 470 } 471 472 /* 473 * SWAP_STATS: get stats on current # of configured swap devs 474 * 475 * note that the swap_priority list can't change as long 476 * as we are holding the swap_syscall_lock. we don't want 477 * to grab the uvm.swap_data_lock because we may fault&sleep during 478 * copyout() and we don't want to be holding that lock then! 479 */ 480 if (SCARG(uap, cmd) == SWAP_STATS 481 #if defined(COMPAT_13) 482 || SCARG(uap, cmd) == SWAP_OSTATS 483 #endif 484 ) { 485 if ((size_t)misc > (size_t)uvmexp.nswapdev) 486 misc = uvmexp.nswapdev; 487 #if defined(COMPAT_13) 488 if (SCARG(uap, cmd) == SWAP_OSTATS) 489 len = sizeof(struct oswapent) * misc; 490 else 491 #endif 492 len = sizeof(struct swapent) * misc; 493 sep = (struct swapent *)malloc(len, M_TEMP, M_WAITOK); 494 495 uvm_swap_stats_locked(SCARG(uap, cmd), sep, misc, retval); 496 error = copyout(sep, SCARG(uap, arg), len); 497 498 free(sep, M_TEMP); 499 UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); 500 goto out; 501 } 502 if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { 503 dev_t *devp = (dev_t *)SCARG(uap, arg); 504 505 error = copyout(&dumpdev, devp, sizeof(dumpdev)); 506 goto out; 507 } 508 509 /* 510 * all other requests require superuser privs. verify. 511 */ 512 if ((error = kauth_authorize_generic(p->p_cred, KAUTH_GENERIC_ISSUSER, 513 &p->p_acflag))) 514 goto out; 515 516 /* 517 * at this point we expect a path name in arg. we will 518 * use namei() to gain a vnode reference (vref), and lock 519 * the vnode (VOP_LOCK). 520 * 521 * XXX: a NULL arg means use the root vnode pointer (e.g. for 522 * miniroot) 523 */ 524 if (SCARG(uap, arg) == NULL) { 525 vp = rootvp; /* miniroot */ 526 if (vget(vp, LK_EXCLUSIVE)) { 527 error = EBUSY; 528 goto out; 529 } 530 if (SCARG(uap, cmd) == SWAP_ON && 531 copystr("miniroot", userpath, SWAP_PATH_MAX, &len)) 532 panic("swapctl: miniroot copy failed"); 533 } else { 534 int space; 535 char *where; 536 537 if (SCARG(uap, cmd) == SWAP_ON) { 538 if ((error = copyinstr(SCARG(uap, arg), userpath, 539 SWAP_PATH_MAX, &len))) 540 goto out; 541 space = UIO_SYSSPACE; 542 where = userpath; 543 } else { 544 space = UIO_USERSPACE; 545 where = (char *)SCARG(uap, arg); 546 } 547 NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, space, where, l); 548 if ((error = namei(&nd))) 549 goto out; 550 vp = nd.ni_vp; 551 } 552 /* note: "vp" is referenced and locked */ 553 554 error = 0; /* assume no error */ 555 switch(SCARG(uap, cmd)) { 556 557 case SWAP_DUMPDEV: 558 if (vp->v_type != VBLK) { 559 error = ENOTBLK; 560 break; 561 } 562 dumpdev = vp->v_rdev; 563 cpu_dumpconf(); 564 break; 565 566 case SWAP_CTL: 567 /* 568 * get new priority, remove old entry (if any) and then 569 * reinsert it in the correct place. finally, prune out 570 * any empty priority structures. 571 */ 572 priority = SCARG(uap, misc); 573 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 574 simple_lock(&uvm.swap_data_lock); 575 if ((sdp = swaplist_find(vp, 1)) == NULL) { 576 error = ENOENT; 577 } else { 578 swaplist_insert(sdp, spp, priority); 579 swaplist_trim(); 580 } 581 simple_unlock(&uvm.swap_data_lock); 582 if (error) 583 free(spp, M_VMSWAP); 584 break; 585 586 case SWAP_ON: 587 588 /* 589 * check for duplicates. if none found, then insert a 590 * dummy entry on the list to prevent someone else from 591 * trying to enable this device while we are working on 592 * it. 593 */ 594 595 priority = SCARG(uap, misc); 596 sdp = malloc(sizeof *sdp, M_VMSWAP, M_WAITOK); 597 spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); 598 memset(sdp, 0, sizeof(*sdp)); 599 sdp->swd_flags = SWF_FAKE; 600 sdp->swd_vp = vp; 601 sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; 602 bufq_alloc(&sdp->swd_tab, "disksort", BUFQ_SORT_RAWBLOCK); 603 simple_lock(&uvm.swap_data_lock); 604 if (swaplist_find(vp, 0) != NULL) { 605 error = EBUSY; 606 simple_unlock(&uvm.swap_data_lock); 607 bufq_free(sdp->swd_tab); 608 free(sdp, M_VMSWAP); 609 free(spp, M_VMSWAP); 610 break; 611 } 612 swaplist_insert(sdp, spp, priority); 613 simple_unlock(&uvm.swap_data_lock); 614 615 sdp->swd_pathlen = len; 616 sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); 617 if (copystr(userpath, sdp->swd_path, sdp->swd_pathlen, 0) != 0) 618 panic("swapctl: copystr"); 619 620 /* 621 * we've now got a FAKE placeholder in the swap list. 622 * now attempt to enable swap on it. if we fail, undo 623 * what we've done and kill the fake entry we just inserted. 624 * if swap_on is a success, it will clear the SWF_FAKE flag 625 */ 626 627 if ((error = swap_on(l, sdp)) != 0) { 628 simple_lock(&uvm.swap_data_lock); 629 (void) swaplist_find(vp, 1); /* kill fake entry */ 630 swaplist_trim(); 631 simple_unlock(&uvm.swap_data_lock); 632 bufq_free(sdp->swd_tab); 633 free(sdp->swd_path, M_VMSWAP); 634 free(sdp, M_VMSWAP); 635 break; 636 } 637 break; 638 639 case SWAP_OFF: 640 simple_lock(&uvm.swap_data_lock); 641 if ((sdp = swaplist_find(vp, 0)) == NULL) { 642 simple_unlock(&uvm.swap_data_lock); 643 error = ENXIO; 644 break; 645 } 646 647 /* 648 * If a device isn't in use or enabled, we 649 * can't stop swapping from it (again). 650 */ 651 if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { 652 simple_unlock(&uvm.swap_data_lock); 653 error = EBUSY; 654 break; 655 } 656 657 /* 658 * do the real work. 659 */ 660 error = swap_off(l, sdp); 661 break; 662 663 default: 664 error = EINVAL; 665 } 666 667 /* 668 * done! release the ref gained by namei() and unlock. 669 */ 670 vput(vp); 671 672 out: 673 free(userpath, M_TEMP); 674 lockmgr(&swap_syscall_lock, LK_RELEASE, NULL); 675 676 UVMHIST_LOG(pdhist, "<- done! error=%d", error, 0, 0, 0); 677 return (error); 678 } 679 680 /* 681 * swap_stats: implements swapctl(SWAP_STATS). The function is kept 682 * away from sys_swapctl() in order to allow COMPAT_* swapctl() 683 * emulation to use it directly without going through sys_swapctl(). 684 * The problem with using sys_swapctl() there is that it involves 685 * copying the swapent array to the stackgap, and this array's size 686 * is not known at build time. Hence it would not be possible to 687 * ensure it would fit in the stackgap in any case. 688 */ 689 void 690 uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) 691 { 692 693 lockmgr(&swap_syscall_lock, LK_EXCLUSIVE, NULL); 694 uvm_swap_stats_locked(cmd, sep, sec, retval); 695 lockmgr(&swap_syscall_lock, LK_RELEASE, NULL); 696 } 697 698 static void 699 uvm_swap_stats_locked(int cmd, struct swapent *sep, int sec, register_t *retval) 700 { 701 struct swappri *spp; 702 struct swapdev *sdp; 703 int count = 0; 704 705 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 706 for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); 707 sdp != (void *)&spp->spi_swapdev && sec-- > 0; 708 sdp = CIRCLEQ_NEXT(sdp, swd_next)) { 709 /* 710 * backwards compatibility for system call. 711 * note that we use 'struct oswapent' as an 712 * overlay into both 'struct swapdev' and 713 * the userland 'struct swapent', as we 714 * want to retain backwards compatibility 715 * with NetBSD 1.3. 716 */ 717 sdp->swd_ose.ose_inuse = 718 btodb((uint64_t)sdp->swd_npginuse << 719 PAGE_SHIFT); 720 (void)memcpy(sep, &sdp->swd_ose, 721 sizeof(struct oswapent)); 722 723 /* now copy out the path if necessary */ 724 #if defined(COMPAT_13) 725 if (cmd == SWAP_STATS) 726 #endif 727 (void)memcpy(&sep->se_path, sdp->swd_path, 728 sdp->swd_pathlen); 729 730 count++; 731 #if defined(COMPAT_13) 732 if (cmd == SWAP_OSTATS) 733 sep = (struct swapent *) 734 ((struct oswapent *)sep + 1); 735 else 736 #endif 737 sep++; 738 } 739 } 740 741 *retval = count; 742 return; 743 } 744 745 /* 746 * swap_on: attempt to enable a swapdev for swapping. note that the 747 * swapdev is already on the global list, but disabled (marked 748 * SWF_FAKE). 749 * 750 * => we avoid the start of the disk (to protect disk labels) 751 * => we also avoid the miniroot, if we are swapping to root. 752 * => caller should leave uvm.swap_data_lock unlocked, we may lock it 753 * if needed. 754 */ 755 static int 756 swap_on(struct lwp *l, struct swapdev *sdp) 757 { 758 struct vnode *vp; 759 struct proc *p = l->l_proc; 760 int error, npages, nblocks, size; 761 long addr; 762 u_long result; 763 struct vattr va; 764 #ifdef NFS 765 extern int (**nfsv2_vnodeop_p)(void *); 766 #endif /* NFS */ 767 const struct bdevsw *bdev; 768 dev_t dev; 769 UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); 770 771 /* 772 * we want to enable swapping on sdp. the swd_vp contains 773 * the vnode we want (locked and ref'd), and the swd_dev 774 * contains the dev_t of the file, if it a block device. 775 */ 776 777 vp = sdp->swd_vp; 778 dev = sdp->swd_dev; 779 780 /* 781 * open the swap file (mostly useful for block device files to 782 * let device driver know what is up). 783 * 784 * we skip the open/close for root on swap because the root 785 * has already been opened when root was mounted (mountroot). 786 */ 787 if (vp != rootvp) { 788 if ((error = VOP_OPEN(vp, FREAD|FWRITE, p->p_cred, l))) 789 return (error); 790 } 791 792 /* XXX this only works for block devices */ 793 UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d", dev, major(dev), 0,0); 794 795 /* 796 * we now need to determine the size of the swap area. for 797 * block specials we can call the d_psize function. 798 * for normal files, we must stat [get attrs]. 799 * 800 * we put the result in nblks. 801 * for normal files, we also want the filesystem block size 802 * (which we get with statfs). 803 */ 804 switch (vp->v_type) { 805 case VBLK: 806 bdev = bdevsw_lookup(dev); 807 if (bdev == NULL || bdev->d_psize == NULL || 808 (nblocks = (*bdev->d_psize)(dev)) == -1) { 809 error = ENXIO; 810 goto bad; 811 } 812 break; 813 814 case VREG: 815 if ((error = VOP_GETATTR(vp, &va, p->p_cred, l))) 816 goto bad; 817 nblocks = (int)btodb(va.va_size); 818 if ((error = 819 VFS_STATVFS(vp->v_mount, &vp->v_mount->mnt_stat, l)) != 0) 820 goto bad; 821 822 sdp->swd_bsize = vp->v_mount->mnt_stat.f_iosize; 823 /* 824 * limit the max # of outstanding I/O requests we issue 825 * at any one time. take it easy on NFS servers. 826 */ 827 #ifdef NFS 828 if (vp->v_op == nfsv2_vnodeop_p) 829 sdp->swd_maxactive = 2; /* XXX */ 830 else 831 #endif /* NFS */ 832 sdp->swd_maxactive = 8; /* XXX */ 833 break; 834 835 default: 836 error = ENXIO; 837 goto bad; 838 } 839 840 /* 841 * save nblocks in a safe place and convert to pages. 842 */ 843 844 sdp->swd_ose.ose_nblks = nblocks; 845 npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; 846 847 /* 848 * for block special files, we want to make sure that leave 849 * the disklabel and bootblocks alone, so we arrange to skip 850 * over them (arbitrarily choosing to skip PAGE_SIZE bytes). 851 * note that because of this the "size" can be less than the 852 * actual number of blocks on the device. 853 */ 854 if (vp->v_type == VBLK) { 855 /* we use pages 1 to (size - 1) [inclusive] */ 856 size = npages - 1; 857 addr = 1; 858 } else { 859 /* we use pages 0 to (size - 1) [inclusive] */ 860 size = npages; 861 addr = 0; 862 } 863 864 /* 865 * make sure we have enough blocks for a reasonable sized swap 866 * area. we want at least one page. 867 */ 868 869 if (size < 1) { 870 UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); 871 error = EINVAL; 872 goto bad; 873 } 874 875 UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld\n", dev, size, addr, 0); 876 877 /* 878 * now we need to allocate an extent to manage this swap device 879 */ 880 881 sdp->swd_blist = blist_create(npages); 882 /* mark all expect the `saved' region free. */ 883 blist_free(sdp->swd_blist, addr, size); 884 885 /* 886 * if the vnode we are swapping to is the root vnode 887 * (i.e. we are swapping to the miniroot) then we want 888 * to make sure we don't overwrite it. do a statfs to 889 * find its size and skip over it. 890 */ 891 if (vp == rootvp) { 892 struct mount *mp; 893 struct statvfs *sp; 894 int rootblocks, rootpages; 895 896 mp = rootvnode->v_mount; 897 sp = &mp->mnt_stat; 898 rootblocks = sp->f_blocks * btodb(sp->f_frsize); 899 /* 900 * XXX: sp->f_blocks isn't the total number of 901 * blocks in the filesystem, it's the number of 902 * data blocks. so, our rootblocks almost 903 * definitely underestimates the total size 904 * of the filesystem - how badly depends on the 905 * details of the filesystem type. there isn't 906 * an obvious way to deal with this cleanly 907 * and perfectly, so for now we just pad our 908 * rootblocks estimate with an extra 5 percent. 909 */ 910 rootblocks += (rootblocks >> 5) + 911 (rootblocks >> 6) + 912 (rootblocks >> 7); 913 rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; 914 if (rootpages > size) 915 panic("swap_on: miniroot larger than swap?"); 916 917 if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { 918 panic("swap_on: unable to preserve miniroot"); 919 } 920 921 size -= rootpages; 922 printf("Preserved %d pages of miniroot ", rootpages); 923 printf("leaving %d pages of swap\n", size); 924 } 925 926 /* 927 * add a ref to vp to reflect usage as a swap device. 928 */ 929 vref(vp); 930 931 /* 932 * now add the new swapdev to the drum and enable. 933 */ 934 if (extent_alloc(swapmap, npages, EX_NOALIGN, EX_NOBOUNDARY, 935 EX_WAITOK, &result)) 936 panic("swapdrum_add"); 937 938 sdp->swd_drumoffset = (int)result; 939 sdp->swd_drumsize = npages; 940 sdp->swd_npages = size; 941 simple_lock(&uvm.swap_data_lock); 942 sdp->swd_flags &= ~SWF_FAKE; /* going live */ 943 sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); 944 uvmexp.swpages += size; 945 uvmexp.swpgavail += size; 946 simple_unlock(&uvm.swap_data_lock); 947 return (0); 948 949 /* 950 * failure: clean up and return error. 951 */ 952 953 bad: 954 if (sdp->swd_blist) { 955 blist_destroy(sdp->swd_blist); 956 } 957 if (vp != rootvp) { 958 (void)VOP_CLOSE(vp, FREAD|FWRITE, p->p_cred, l); 959 } 960 return (error); 961 } 962 963 /* 964 * swap_off: stop swapping on swapdev 965 * 966 * => swap data should be locked, we will unlock. 967 */ 968 static int 969 swap_off(struct lwp *l, struct swapdev *sdp) 970 { 971 struct proc *p = l->l_proc; 972 int npages = sdp->swd_npages; 973 int error = 0; 974 975 UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); 976 UVMHIST_LOG(pdhist, " dev=%x, npages=%d", sdp->swd_dev,npages,0,0); 977 978 /* disable the swap area being removed */ 979 sdp->swd_flags &= ~SWF_ENABLE; 980 uvmexp.swpgavail -= npages; 981 simple_unlock(&uvm.swap_data_lock); 982 983 /* 984 * the idea is to find all the pages that are paged out to this 985 * device, and page them all in. in uvm, swap-backed pageable 986 * memory can take two forms: aobjs and anons. call the 987 * swapoff hook for each subsystem to bring in pages. 988 */ 989 990 if (uao_swap_off(sdp->swd_drumoffset, 991 sdp->swd_drumoffset + sdp->swd_drumsize) || 992 amap_swap_off(sdp->swd_drumoffset, 993 sdp->swd_drumoffset + sdp->swd_drumsize)) { 994 error = ENOMEM; 995 } else if (sdp->swd_npginuse > sdp->swd_npgbad) { 996 error = EBUSY; 997 } 998 999 if (error) { 1000 simple_lock(&uvm.swap_data_lock); 1001 sdp->swd_flags |= SWF_ENABLE; 1002 uvmexp.swpgavail += npages; 1003 simple_unlock(&uvm.swap_data_lock); 1004 1005 return error; 1006 } 1007 1008 /* 1009 * done with the vnode. 1010 * drop our ref on the vnode before calling VOP_CLOSE() 1011 * so that spec_close() can tell if this is the last close. 1012 */ 1013 vrele(sdp->swd_vp); 1014 if (sdp->swd_vp != rootvp) { 1015 (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, p->p_cred, l); 1016 } 1017 1018 simple_lock(&uvm.swap_data_lock); 1019 uvmexp.swpages -= npages; 1020 uvmexp.swpginuse -= sdp->swd_npgbad; 1021 1022 if (swaplist_find(sdp->swd_vp, 1) == NULL) 1023 panic("swap_off: swapdev not in list"); 1024 swaplist_trim(); 1025 simple_unlock(&uvm.swap_data_lock); 1026 1027 /* 1028 * free all resources! 1029 */ 1030 extent_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize, 1031 EX_WAITOK); 1032 blist_destroy(sdp->swd_blist); 1033 bufq_free(sdp->swd_tab); 1034 free(sdp, M_VMSWAP); 1035 return (0); 1036 } 1037 1038 /* 1039 * /dev/drum interface and i/o functions 1040 */ 1041 1042 /* 1043 * swstrategy: perform I/O on the drum 1044 * 1045 * => we must map the i/o request from the drum to the correct swapdev. 1046 */ 1047 static void 1048 swstrategy(struct buf *bp) 1049 { 1050 struct swapdev *sdp; 1051 struct vnode *vp; 1052 int s, pageno, bn; 1053 UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); 1054 1055 /* 1056 * convert block number to swapdev. note that swapdev can't 1057 * be yanked out from under us because we are holding resources 1058 * in it (i.e. the blocks we are doing I/O on). 1059 */ 1060 pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; 1061 simple_lock(&uvm.swap_data_lock); 1062 sdp = swapdrum_getsdp(pageno); 1063 simple_unlock(&uvm.swap_data_lock); 1064 if (sdp == NULL) { 1065 bp->b_error = EINVAL; 1066 bp->b_flags |= B_ERROR; 1067 biodone(bp); 1068 UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); 1069 return; 1070 } 1071 1072 /* 1073 * convert drum page number to block number on this swapdev. 1074 */ 1075 1076 pageno -= sdp->swd_drumoffset; /* page # on swapdev */ 1077 bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ 1078 1079 UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld", 1080 ((bp->b_flags & B_READ) == 0) ? "write" : "read", 1081 sdp->swd_drumoffset, bn, bp->b_bcount); 1082 1083 /* 1084 * for block devices we finish up here. 1085 * for regular files we have to do more work which we delegate 1086 * to sw_reg_strategy(). 1087 */ 1088 1089 switch (sdp->swd_vp->v_type) { 1090 default: 1091 panic("swstrategy: vnode type 0x%x", sdp->swd_vp->v_type); 1092 1093 case VBLK: 1094 1095 /* 1096 * must convert "bp" from an I/O on /dev/drum to an I/O 1097 * on the swapdev (sdp). 1098 */ 1099 s = splbio(); 1100 bp->b_blkno = bn; /* swapdev block number */ 1101 vp = sdp->swd_vp; /* swapdev vnode pointer */ 1102 bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ 1103 1104 /* 1105 * if we are doing a write, we have to redirect the i/o on 1106 * drum's v_numoutput counter to the swapdevs. 1107 */ 1108 if ((bp->b_flags & B_READ) == 0) { 1109 vwakeup(bp); /* kills one 'v_numoutput' on drum */ 1110 V_INCR_NUMOUTPUT(vp); /* put it on swapdev */ 1111 } 1112 1113 /* 1114 * finally plug in swapdev vnode and start I/O 1115 */ 1116 bp->b_vp = vp; 1117 splx(s); 1118 VOP_STRATEGY(vp, bp); 1119 return; 1120 1121 case VREG: 1122 /* 1123 * delegate to sw_reg_strategy function. 1124 */ 1125 sw_reg_strategy(sdp, bp, bn); 1126 return; 1127 } 1128 /* NOTREACHED */ 1129 } 1130 1131 /* 1132 * swread: the read function for the drum (just a call to physio) 1133 */ 1134 /*ARGSUSED*/ 1135 static int 1136 swread(dev_t dev, struct uio *uio, int ioflag) 1137 { 1138 UVMHIST_FUNC("swread"); UVMHIST_CALLED(pdhist); 1139 1140 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1141 return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); 1142 } 1143 1144 /* 1145 * swwrite: the write function for the drum (just a call to physio) 1146 */ 1147 /*ARGSUSED*/ 1148 static int 1149 swwrite(dev_t dev, struct uio *uio, int ioflag) 1150 { 1151 UVMHIST_FUNC("swwrite"); UVMHIST_CALLED(pdhist); 1152 1153 UVMHIST_LOG(pdhist, " dev=%x offset=%qx", dev, uio->uio_offset, 0, 0); 1154 return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); 1155 } 1156 1157 const struct bdevsw swap_bdevsw = { 1158 noopen, noclose, swstrategy, noioctl, nodump, nosize, 1159 }; 1160 1161 const struct cdevsw swap_cdevsw = { 1162 nullopen, nullclose, swread, swwrite, noioctl, 1163 nostop, notty, nopoll, nommap, nokqfilter 1164 }; 1165 1166 /* 1167 * sw_reg_strategy: handle swap i/o to regular files 1168 */ 1169 static void 1170 sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) 1171 { 1172 struct vnode *vp; 1173 struct vndxfer *vnx; 1174 daddr_t nbn; 1175 caddr_t addr; 1176 off_t byteoff; 1177 int s, off, nra, error, sz, resid; 1178 UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); 1179 1180 /* 1181 * allocate a vndxfer head for this transfer and point it to 1182 * our buffer. 1183 */ 1184 getvndxfer(vnx); 1185 vnx->vx_flags = VX_BUSY; 1186 vnx->vx_error = 0; 1187 vnx->vx_pending = 0; 1188 vnx->vx_bp = bp; 1189 vnx->vx_sdp = sdp; 1190 1191 /* 1192 * setup for main loop where we read filesystem blocks into 1193 * our buffer. 1194 */ 1195 error = 0; 1196 bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ 1197 addr = bp->b_data; /* current position in buffer */ 1198 byteoff = dbtob((uint64_t)bn); 1199 1200 for (resid = bp->b_resid; resid; resid -= sz) { 1201 struct vndbuf *nbp; 1202 1203 /* 1204 * translate byteoffset into block number. return values: 1205 * vp = vnode of underlying device 1206 * nbn = new block number (on underlying vnode dev) 1207 * nra = num blocks we can read-ahead (excludes requested 1208 * block) 1209 */ 1210 nra = 0; 1211 error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, 1212 &vp, &nbn, &nra); 1213 1214 if (error == 0 && nbn == (daddr_t)-1) { 1215 /* 1216 * this used to just set error, but that doesn't 1217 * do the right thing. Instead, it causes random 1218 * memory errors. The panic() should remain until 1219 * this condition doesn't destabilize the system. 1220 */ 1221 #if 1 1222 panic("sw_reg_strategy: swap to sparse file"); 1223 #else 1224 error = EIO; /* failure */ 1225 #endif 1226 } 1227 1228 /* 1229 * punt if there was an error or a hole in the file. 1230 * we must wait for any i/o ops we have already started 1231 * to finish before returning. 1232 * 1233 * XXX we could deal with holes here but it would be 1234 * a hassle (in the write case). 1235 */ 1236 if (error) { 1237 s = splbio(); 1238 vnx->vx_error = error; /* pass error up */ 1239 goto out; 1240 } 1241 1242 /* 1243 * compute the size ("sz") of this transfer (in bytes). 1244 */ 1245 off = byteoff % sdp->swd_bsize; 1246 sz = (1 + nra) * sdp->swd_bsize - off; 1247 if (sz > resid) 1248 sz = resid; 1249 1250 UVMHIST_LOG(pdhist, "sw_reg_strategy: " 1251 "vp %p/%p offset 0x%x/0x%x", 1252 sdp->swd_vp, vp, byteoff, nbn); 1253 1254 /* 1255 * now get a buf structure. note that the vb_buf is 1256 * at the front of the nbp structure so that you can 1257 * cast pointers between the two structure easily. 1258 */ 1259 getvndbuf(nbp); 1260 BUF_INIT(&nbp->vb_buf); 1261 nbp->vb_buf.b_flags = bp->b_flags | B_CALL; 1262 nbp->vb_buf.b_bcount = sz; 1263 nbp->vb_buf.b_bufsize = sz; 1264 nbp->vb_buf.b_error = 0; 1265 nbp->vb_buf.b_data = addr; 1266 nbp->vb_buf.b_lblkno = 0; 1267 nbp->vb_buf.b_blkno = nbn + btodb(off); 1268 nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; 1269 nbp->vb_buf.b_iodone = sw_reg_iodone; 1270 nbp->vb_buf.b_vp = vp; 1271 if (vp->v_type == VBLK) { 1272 nbp->vb_buf.b_dev = vp->v_rdev; 1273 } 1274 1275 nbp->vb_xfer = vnx; /* patch it back in to vnx */ 1276 1277 /* 1278 * Just sort by block number 1279 */ 1280 s = splbio(); 1281 if (vnx->vx_error != 0) { 1282 putvndbuf(nbp); 1283 goto out; 1284 } 1285 vnx->vx_pending++; 1286 1287 /* sort it in and start I/O if we are not over our limit */ 1288 BUFQ_PUT(sdp->swd_tab, &nbp->vb_buf); 1289 sw_reg_start(sdp); 1290 splx(s); 1291 1292 /* 1293 * advance to the next I/O 1294 */ 1295 byteoff += sz; 1296 addr += sz; 1297 } 1298 1299 s = splbio(); 1300 1301 out: /* Arrive here at splbio */ 1302 vnx->vx_flags &= ~VX_BUSY; 1303 if (vnx->vx_pending == 0) { 1304 if (vnx->vx_error != 0) { 1305 bp->b_error = vnx->vx_error; 1306 bp->b_flags |= B_ERROR; 1307 } 1308 putvndxfer(vnx); 1309 biodone(bp); 1310 } 1311 splx(s); 1312 } 1313 1314 /* 1315 * sw_reg_start: start an I/O request on the requested swapdev 1316 * 1317 * => reqs are sorted by b_rawblkno (above) 1318 */ 1319 static void 1320 sw_reg_start(struct swapdev *sdp) 1321 { 1322 struct buf *bp; 1323 UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); 1324 1325 /* recursion control */ 1326 if ((sdp->swd_flags & SWF_BUSY) != 0) 1327 return; 1328 1329 sdp->swd_flags |= SWF_BUSY; 1330 1331 while (sdp->swd_active < sdp->swd_maxactive) { 1332 bp = BUFQ_GET(sdp->swd_tab); 1333 if (bp == NULL) 1334 break; 1335 sdp->swd_active++; 1336 1337 UVMHIST_LOG(pdhist, 1338 "sw_reg_start: bp %p vp %p blkno %p cnt %lx", 1339 bp, bp->b_vp, bp->b_blkno, bp->b_bcount); 1340 if ((bp->b_flags & B_READ) == 0) 1341 V_INCR_NUMOUTPUT(bp->b_vp); 1342 1343 VOP_STRATEGY(bp->b_vp, bp); 1344 } 1345 sdp->swd_flags &= ~SWF_BUSY; 1346 } 1347 1348 /* 1349 * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup 1350 * 1351 * => note that we can recover the vndbuf struct by casting the buf ptr 1352 */ 1353 static void 1354 sw_reg_iodone(struct buf *bp) 1355 { 1356 struct vndbuf *vbp = (struct vndbuf *) bp; 1357 struct vndxfer *vnx = vbp->vb_xfer; 1358 struct buf *pbp = vnx->vx_bp; /* parent buffer */ 1359 struct swapdev *sdp = vnx->vx_sdp; 1360 int s, resid, error; 1361 UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); 1362 1363 UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p", 1364 vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); 1365 UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", 1366 vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); 1367 1368 /* 1369 * protect vbp at splbio and update. 1370 */ 1371 1372 s = splbio(); 1373 resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; 1374 pbp->b_resid -= resid; 1375 vnx->vx_pending--; 1376 1377 if (vbp->vb_buf.b_flags & B_ERROR) { 1378 /* pass error upward */ 1379 error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; 1380 UVMHIST_LOG(pdhist, " got error=%d !", error, 0, 0, 0); 1381 vnx->vx_error = error; 1382 } 1383 1384 /* 1385 * kill vbp structure 1386 */ 1387 putvndbuf(vbp); 1388 1389 /* 1390 * wrap up this transaction if it has run to completion or, in 1391 * case of an error, when all auxiliary buffers have returned. 1392 */ 1393 if (vnx->vx_error != 0) { 1394 /* pass error upward */ 1395 pbp->b_flags |= B_ERROR; 1396 pbp->b_error = vnx->vx_error; 1397 if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { 1398 putvndxfer(vnx); 1399 biodone(pbp); 1400 } 1401 } else if (pbp->b_resid == 0) { 1402 KASSERT(vnx->vx_pending == 0); 1403 if ((vnx->vx_flags & VX_BUSY) == 0) { 1404 UVMHIST_LOG(pdhist, " iodone error=%d !", 1405 pbp, vnx->vx_error, 0, 0); 1406 putvndxfer(vnx); 1407 biodone(pbp); 1408 } 1409 } 1410 1411 /* 1412 * done! start next swapdev I/O if one is pending 1413 */ 1414 sdp->swd_active--; 1415 sw_reg_start(sdp); 1416 splx(s); 1417 } 1418 1419 1420 /* 1421 * uvm_swap_alloc: allocate space on swap 1422 * 1423 * => allocation is done "round robin" down the priority list, as we 1424 * allocate in a priority we "rotate" the circle queue. 1425 * => space can be freed with uvm_swap_free 1426 * => we return the page slot number in /dev/drum (0 == invalid slot) 1427 * => we lock uvm.swap_data_lock 1428 * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM 1429 */ 1430 int 1431 uvm_swap_alloc(int *nslots /* IN/OUT */, boolean_t lessok) 1432 { 1433 struct swapdev *sdp; 1434 struct swappri *spp; 1435 UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); 1436 1437 /* 1438 * no swap devices configured yet? definite failure. 1439 */ 1440 if (uvmexp.nswapdev < 1) 1441 return 0; 1442 1443 /* 1444 * lock data lock, convert slots into blocks, and enter loop 1445 */ 1446 simple_lock(&uvm.swap_data_lock); 1447 1448 ReTry: /* XXXMRG */ 1449 LIST_FOREACH(spp, &swap_priority, spi_swappri) { 1450 CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { 1451 uint64_t result; 1452 1453 /* if it's not enabled, then we can't swap from it */ 1454 if ((sdp->swd_flags & SWF_ENABLE) == 0) 1455 continue; 1456 if (sdp->swd_npginuse + *nslots > sdp->swd_npages) 1457 continue; 1458 result = blist_alloc(sdp->swd_blist, *nslots); 1459 if (result == BLIST_NONE) { 1460 continue; 1461 } 1462 KASSERT(result < sdp->swd_drumsize); 1463 1464 /* 1465 * successful allocation! now rotate the circleq. 1466 */ 1467 CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); 1468 CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); 1469 sdp->swd_npginuse += *nslots; 1470 uvmexp.swpginuse += *nslots; 1471 simple_unlock(&uvm.swap_data_lock); 1472 /* done! return drum slot number */ 1473 UVMHIST_LOG(pdhist, 1474 "success! returning %d slots starting at %d", 1475 *nslots, result + sdp->swd_drumoffset, 0, 0); 1476 return (result + sdp->swd_drumoffset); 1477 } 1478 } 1479 1480 /* XXXMRG: BEGIN HACK */ 1481 if (*nslots > 1 && lessok) { 1482 *nslots = 1; 1483 /* XXXMRG: ugh! blist should support this for us */ 1484 goto ReTry; 1485 } 1486 /* XXXMRG: END HACK */ 1487 1488 simple_unlock(&uvm.swap_data_lock); 1489 return 0; 1490 } 1491 1492 boolean_t 1493 uvm_swapisfull(void) 1494 { 1495 boolean_t rv; 1496 1497 simple_lock(&uvm.swap_data_lock); 1498 KASSERT(uvmexp.swpgonly <= uvmexp.swpages); 1499 rv = (uvmexp.swpgonly >= uvmexp.swpgavail); 1500 simple_unlock(&uvm.swap_data_lock); 1501 1502 return (rv); 1503 } 1504 1505 /* 1506 * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors 1507 * 1508 * => we lock uvm.swap_data_lock 1509 */ 1510 void 1511 uvm_swap_markbad(int startslot, int nslots) 1512 { 1513 struct swapdev *sdp; 1514 UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); 1515 1516 simple_lock(&uvm.swap_data_lock); 1517 sdp = swapdrum_getsdp(startslot); 1518 KASSERT(sdp != NULL); 1519 1520 /* 1521 * we just keep track of how many pages have been marked bad 1522 * in this device, to make everything add up in swap_off(). 1523 * we assume here that the range of slots will all be within 1524 * one swap device. 1525 */ 1526 1527 KASSERT(uvmexp.swpgonly >= nslots); 1528 uvmexp.swpgonly -= nslots; 1529 sdp->swd_npgbad += nslots; 1530 UVMHIST_LOG(pdhist, "now %d bad", sdp->swd_npgbad, 0,0,0); 1531 simple_unlock(&uvm.swap_data_lock); 1532 } 1533 1534 /* 1535 * uvm_swap_free: free swap slots 1536 * 1537 * => this can be all or part of an allocation made by uvm_swap_alloc 1538 * => we lock uvm.swap_data_lock 1539 */ 1540 void 1541 uvm_swap_free(int startslot, int nslots) 1542 { 1543 struct swapdev *sdp; 1544 UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); 1545 1546 UVMHIST_LOG(pdhist, "freeing %d slots starting at %d", nslots, 1547 startslot, 0, 0); 1548 1549 /* 1550 * ignore attempts to free the "bad" slot. 1551 */ 1552 1553 if (startslot == SWSLOT_BAD) { 1554 return; 1555 } 1556 1557 /* 1558 * convert drum slot offset back to sdp, free the blocks 1559 * in the extent, and return. must hold pri lock to do 1560 * lookup and access the extent. 1561 */ 1562 1563 simple_lock(&uvm.swap_data_lock); 1564 sdp = swapdrum_getsdp(startslot); 1565 KASSERT(uvmexp.nswapdev >= 1); 1566 KASSERT(sdp != NULL); 1567 KASSERT(sdp->swd_npginuse >= nslots); 1568 blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); 1569 sdp->swd_npginuse -= nslots; 1570 uvmexp.swpginuse -= nslots; 1571 simple_unlock(&uvm.swap_data_lock); 1572 } 1573 1574 /* 1575 * uvm_swap_put: put any number of pages into a contig place on swap 1576 * 1577 * => can be sync or async 1578 */ 1579 1580 int 1581 uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) 1582 { 1583 int error; 1584 1585 error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | 1586 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1587 return error; 1588 } 1589 1590 /* 1591 * uvm_swap_get: get a single page from swap 1592 * 1593 * => usually a sync op (from fault) 1594 */ 1595 1596 int 1597 uvm_swap_get(struct vm_page *page, int swslot, int flags) 1598 { 1599 int error; 1600 1601 uvmexp.nswget++; 1602 KASSERT(flags & PGO_SYNCIO); 1603 if (swslot == SWSLOT_BAD) { 1604 return EIO; 1605 } 1606 1607 error = uvm_swap_io(&page, swslot, 1, B_READ | 1608 ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); 1609 if (error == 0) { 1610 1611 /* 1612 * this page is no longer only in swap. 1613 */ 1614 1615 simple_lock(&uvm.swap_data_lock); 1616 KASSERT(uvmexp.swpgonly > 0); 1617 uvmexp.swpgonly--; 1618 simple_unlock(&uvm.swap_data_lock); 1619 } 1620 return error; 1621 } 1622 1623 /* 1624 * uvm_swap_io: do an i/o operation to swap 1625 */ 1626 1627 static int 1628 uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) 1629 { 1630 daddr_t startblk; 1631 struct buf *bp; 1632 vaddr_t kva; 1633 int error, s, mapinflags; 1634 boolean_t write, async; 1635 UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); 1636 1637 UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d", 1638 startslot, npages, flags, 0); 1639 1640 write = (flags & B_READ) == 0; 1641 async = (flags & B_ASYNC) != 0; 1642 1643 /* 1644 * convert starting drum slot to block number 1645 */ 1646 1647 startblk = btodb((uint64_t)startslot << PAGE_SHIFT); 1648 1649 /* 1650 * first, map the pages into the kernel. 1651 */ 1652 1653 mapinflags = !write ? 1654 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : 1655 UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; 1656 kva = uvm_pagermapin(pps, npages, mapinflags); 1657 1658 /* 1659 * now allocate a buf for the i/o. 1660 */ 1661 1662 bp = getiobuf(); 1663 1664 /* 1665 * fill in the bp/sbp. we currently route our i/o through 1666 * /dev/drum's vnode [swapdev_vp]. 1667 */ 1668 1669 bp->b_flags = B_BUSY | B_NOCACHE | (flags & (B_READ|B_ASYNC)); 1670 bp->b_proc = &proc0; /* XXX */ 1671 bp->b_vnbufs.le_next = NOLIST; 1672 bp->b_data = (caddr_t)kva; 1673 bp->b_blkno = startblk; 1674 bp->b_vp = swapdev_vp; 1675 bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; 1676 1677 /* 1678 * bump v_numoutput (counter of number of active outputs). 1679 */ 1680 1681 if (write) { 1682 s = splbio(); 1683 V_INCR_NUMOUTPUT(swapdev_vp); 1684 splx(s); 1685 } 1686 1687 /* 1688 * for async ops we must set up the iodone handler. 1689 */ 1690 1691 if (async) { 1692 bp->b_flags |= B_CALL; 1693 bp->b_iodone = uvm_aio_biodone; 1694 UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); 1695 if (curproc == uvm.pagedaemon_proc) 1696 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1697 else 1698 BIO_SETPRIO(bp, BPRIO_TIMELIMITED); 1699 } else { 1700 BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); 1701 } 1702 UVMHIST_LOG(pdhist, 1703 "about to start io: data = %p blkno = 0x%x, bcount = %ld", 1704 bp->b_data, bp->b_blkno, bp->b_bcount, 0); 1705 1706 /* 1707 * now we start the I/O, and if async, return. 1708 */ 1709 1710 VOP_STRATEGY(swapdev_vp, bp); 1711 if (async) 1712 return 0; 1713 1714 /* 1715 * must be sync i/o. wait for it to finish 1716 */ 1717 1718 error = biowait(bp); 1719 1720 /* 1721 * kill the pager mapping 1722 */ 1723 1724 uvm_pagermapout(kva, npages); 1725 1726 /* 1727 * now dispose of the buf and we're done. 1728 */ 1729 1730 s = splbio(); 1731 if (write) 1732 vwakeup(bp); 1733 putiobuf(bp); 1734 splx(s); 1735 UVMHIST_LOG(pdhist, "<- done (sync) error=%d", error, 0, 0, 0); 1736 return (error); 1737 } 1738