| 1 | /* $NetBSD: uvm_swap.c,v 1.174 2016/07/08 06:45:34 skrll 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 1.174 2016/07/08 06:45:34 skrll Exp $" ); |
| 34 | |
| 35 | #include "opt_uvmhist.h" |
| 36 | #include "opt_compat_netbsd.h" |
| 37 | #include "opt_ddb.h" |
| 38 | |
| 39 | #include <sys/param.h> |
| 40 | #include <sys/systm.h> |
| 41 | #include <sys/buf.h> |
| 42 | #include <sys/bufq.h> |
| 43 | #include <sys/conf.h> |
| 44 | #include <sys/proc.h> |
| 45 | #include <sys/namei.h> |
| 46 | #include <sys/disklabel.h> |
| 47 | #include <sys/errno.h> |
| 48 | #include <sys/kernel.h> |
| 49 | #include <sys/vnode.h> |
| 50 | #include <sys/file.h> |
| 51 | #include <sys/vmem.h> |
| 52 | #include <sys/blist.h> |
| 53 | #include <sys/mount.h> |
| 54 | #include <sys/pool.h> |
| 55 | #include <sys/kmem.h> |
| 56 | #include <sys/syscallargs.h> |
| 57 | #include <sys/swap.h> |
| 58 | #include <sys/kauth.h> |
| 59 | #include <sys/sysctl.h> |
| 60 | #include <sys/workqueue.h> |
| 61 | |
| 62 | #include <uvm/uvm.h> |
| 63 | |
| 64 | #include <miscfs/specfs/specdev.h> |
| 65 | |
| 66 | /* |
| 67 | * uvm_swap.c: manage configuration and i/o to swap space. |
| 68 | */ |
| 69 | |
| 70 | /* |
| 71 | * swap space is managed in the following way: |
| 72 | * |
| 73 | * each swap partition or file is described by a "swapdev" structure. |
| 74 | * each "swapdev" structure contains a "swapent" structure which contains |
| 75 | * information that is passed up to the user (via system calls). |
| 76 | * |
| 77 | * each swap partition is assigned a "priority" (int) which controls |
| 78 | * swap parition usage. |
| 79 | * |
| 80 | * the system maintains a global data structure describing all swap |
| 81 | * partitions/files. there is a sorted LIST of "swappri" structures |
| 82 | * which describe "swapdev"'s at that priority. this LIST is headed |
| 83 | * by the "swap_priority" global var. each "swappri" contains a |
| 84 | * TAILQ of "swapdev" structures at that priority. |
| 85 | * |
| 86 | * locking: |
| 87 | * - swap_syscall_lock (krwlock_t): this lock serializes the swapctl |
| 88 | * system call and prevents the swap priority list from changing |
| 89 | * while we are in the middle of a system call (e.g. SWAP_STATS). |
| 90 | * - uvm_swap_data_lock (kmutex_t): this lock protects all swap data |
| 91 | * structures including the priority list, the swapdev structures, |
| 92 | * and the swapmap arena. |
| 93 | * |
| 94 | * each swap device has the following info: |
| 95 | * - swap device in use (could be disabled, preventing future use) |
| 96 | * - swap enabled (allows new allocations on swap) |
| 97 | * - map info in /dev/drum |
| 98 | * - vnode pointer |
| 99 | * for swap files only: |
| 100 | * - block size |
| 101 | * - max byte count in buffer |
| 102 | * - buffer |
| 103 | * |
| 104 | * userland controls and configures swap with the swapctl(2) system call. |
| 105 | * the sys_swapctl performs the following operations: |
| 106 | * [1] SWAP_NSWAP: returns the number of swap devices currently configured |
| 107 | * [2] SWAP_STATS: given a pointer to an array of swapent structures |
| 108 | * (passed in via "arg") of a size passed in via "misc" ... we load |
| 109 | * the current swap config into the array. The actual work is done |
| 110 | * in the uvm_swap_stats() function. |
| 111 | * [3] SWAP_ON: given a pathname in arg (could be device or file) and a |
| 112 | * priority in "misc", start swapping on it. |
| 113 | * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device |
| 114 | * [5] SWAP_CTL: changes the priority of a swap device (new priority in |
| 115 | * "misc") |
| 116 | */ |
| 117 | |
| 118 | /* |
| 119 | * swapdev: describes a single swap partition/file |
| 120 | * |
| 121 | * note the following should be true: |
| 122 | * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] |
| 123 | * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] |
| 124 | */ |
| 125 | struct swapdev { |
| 126 | dev_t swd_dev; /* device id */ |
| 127 | int swd_flags; /* flags:inuse/enable/fake */ |
| 128 | int swd_priority; /* our priority */ |
| 129 | int swd_nblks; /* blocks in this device */ |
| 130 | char *swd_path; /* saved pathname of device */ |
| 131 | int swd_pathlen; /* length of pathname */ |
| 132 | int swd_npages; /* #pages we can use */ |
| 133 | int swd_npginuse; /* #pages in use */ |
| 134 | int swd_npgbad; /* #pages bad */ |
| 135 | int swd_drumoffset; /* page0 offset in drum */ |
| 136 | int swd_drumsize; /* #pages in drum */ |
| 137 | blist_t swd_blist; /* blist for this swapdev */ |
| 138 | struct vnode *swd_vp; /* backing vnode */ |
| 139 | TAILQ_ENTRY(swapdev) swd_next; /* priority tailq */ |
| 140 | |
| 141 | int swd_bsize; /* blocksize (bytes) */ |
| 142 | int swd_maxactive; /* max active i/o reqs */ |
| 143 | struct bufq_state *swd_tab; /* buffer list */ |
| 144 | int swd_active; /* number of active buffers */ |
| 145 | }; |
| 146 | |
| 147 | /* |
| 148 | * swap device priority entry; the list is kept sorted on `spi_priority'. |
| 149 | */ |
| 150 | struct swappri { |
| 151 | int spi_priority; /* priority */ |
| 152 | TAILQ_HEAD(spi_swapdev, swapdev) spi_swapdev; |
| 153 | /* tailq of swapdevs at this priority */ |
| 154 | LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ |
| 155 | }; |
| 156 | |
| 157 | /* |
| 158 | * The following two structures are used to keep track of data transfers |
| 159 | * on swap devices associated with regular files. |
| 160 | * NOTE: this code is more or less a copy of vnd.c; we use the same |
| 161 | * structure names here to ease porting.. |
| 162 | */ |
| 163 | struct vndxfer { |
| 164 | struct buf *vx_bp; /* Pointer to parent buffer */ |
| 165 | struct swapdev *vx_sdp; |
| 166 | int vx_error; |
| 167 | int vx_pending; /* # of pending aux buffers */ |
| 168 | int vx_flags; |
| 169 | #define VX_BUSY 1 |
| 170 | #define VX_DEAD 2 |
| 171 | }; |
| 172 | |
| 173 | struct vndbuf { |
| 174 | struct buf vb_buf; |
| 175 | struct vndxfer *vb_xfer; |
| 176 | }; |
| 177 | |
| 178 | /* |
| 179 | * NetBSD 1.3 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit |
| 180 | * dev_t and has no se_path[] member. |
| 181 | */ |
| 182 | struct swapent13 { |
| 183 | int32_t se13_dev; /* device id */ |
| 184 | int se13_flags; /* flags */ |
| 185 | int se13_nblks; /* total blocks */ |
| 186 | int se13_inuse; /* blocks in use */ |
| 187 | int se13_priority; /* priority of this device */ |
| 188 | }; |
| 189 | |
| 190 | /* |
| 191 | * NetBSD 5.0 swapctl(SWAP_STATS, ...) swapent structure; uses 32 bit |
| 192 | * dev_t. |
| 193 | */ |
| 194 | struct swapent50 { |
| 195 | int32_t se50_dev; /* device id */ |
| 196 | int se50_flags; /* flags */ |
| 197 | int se50_nblks; /* total blocks */ |
| 198 | int se50_inuse; /* blocks in use */ |
| 199 | int se50_priority; /* priority of this device */ |
| 200 | char se50_path[PATH_MAX+1]; /* path name */ |
| 201 | }; |
| 202 | |
| 203 | /* |
| 204 | * We keep a of pool vndbuf's and vndxfer structures. |
| 205 | */ |
| 206 | static struct pool vndxfer_pool, vndbuf_pool; |
| 207 | |
| 208 | /* |
| 209 | * local variables |
| 210 | */ |
| 211 | static vmem_t *swapmap; /* controls the mapping of /dev/drum */ |
| 212 | |
| 213 | /* list of all active swap devices [by priority] */ |
| 214 | LIST_HEAD(swap_priority, swappri); |
| 215 | static struct swap_priority swap_priority; |
| 216 | |
| 217 | /* locks */ |
| 218 | static krwlock_t swap_syscall_lock; |
| 219 | |
| 220 | /* workqueue and use counter for swap to regular files */ |
| 221 | static int sw_reg_count = 0; |
| 222 | static struct workqueue *sw_reg_workqueue; |
| 223 | |
| 224 | /* tuneables */ |
| 225 | u_int uvm_swapisfull_factor = 99; |
| 226 | |
| 227 | /* |
| 228 | * prototypes |
| 229 | */ |
| 230 | static struct swapdev *swapdrum_getsdp(int); |
| 231 | |
| 232 | static struct swapdev *swaplist_find(struct vnode *, bool); |
| 233 | static void swaplist_insert(struct swapdev *, |
| 234 | struct swappri *, int); |
| 235 | static void swaplist_trim(void); |
| 236 | |
| 237 | static int swap_on(struct lwp *, struct swapdev *); |
| 238 | static int swap_off(struct lwp *, struct swapdev *); |
| 239 | |
| 240 | static void sw_reg_strategy(struct swapdev *, struct buf *, int); |
| 241 | static void sw_reg_biodone(struct buf *); |
| 242 | static void sw_reg_iodone(struct work *wk, void *dummy); |
| 243 | static void sw_reg_start(struct swapdev *); |
| 244 | |
| 245 | static int uvm_swap_io(struct vm_page **, int, int, int); |
| 246 | |
| 247 | /* |
| 248 | * uvm_swap_init: init the swap system data structures and locks |
| 249 | * |
| 250 | * => called at boot time from init_main.c after the filesystems |
| 251 | * are brought up (which happens after uvm_init()) |
| 252 | */ |
| 253 | void |
| 254 | uvm_swap_init(void) |
| 255 | { |
| 256 | UVMHIST_FUNC("uvm_swap_init" ); |
| 257 | |
| 258 | UVMHIST_CALLED(pdhist); |
| 259 | /* |
| 260 | * first, init the swap list, its counter, and its lock. |
| 261 | * then get a handle on the vnode for /dev/drum by using |
| 262 | * the its dev_t number ("swapdev", from MD conf.c). |
| 263 | */ |
| 264 | |
| 265 | LIST_INIT(&swap_priority); |
| 266 | uvmexp.nswapdev = 0; |
| 267 | rw_init(&swap_syscall_lock); |
| 268 | mutex_init(&uvm_swap_data_lock, MUTEX_DEFAULT, IPL_NONE); |
| 269 | |
| 270 | if (bdevvp(swapdev, &swapdev_vp)) |
| 271 | panic("%s: can't get vnode for swap device" , __func__); |
| 272 | if (vn_lock(swapdev_vp, LK_EXCLUSIVE | LK_RETRY)) |
| 273 | panic("%s: can't lock swap device" , __func__); |
| 274 | if (VOP_OPEN(swapdev_vp, FREAD | FWRITE, NOCRED)) |
| 275 | panic("%s: can't open swap device" , __func__); |
| 276 | VOP_UNLOCK(swapdev_vp); |
| 277 | |
| 278 | /* |
| 279 | * create swap block resource map to map /dev/drum. the range |
| 280 | * from 1 to INT_MAX allows 2 gigablocks of swap space. note |
| 281 | * that block 0 is reserved (used to indicate an allocation |
| 282 | * failure, or no allocation). |
| 283 | */ |
| 284 | swapmap = vmem_create("swapmap" , 1, INT_MAX - 1, 1, NULL, NULL, NULL, 0, |
| 285 | VM_NOSLEEP, IPL_NONE); |
| 286 | if (swapmap == 0) { |
| 287 | panic("%s: vmem_create failed" , __func__); |
| 288 | } |
| 289 | |
| 290 | pool_init(&vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx" , |
| 291 | NULL, IPL_BIO); |
| 292 | pool_init(&vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd" , |
| 293 | NULL, IPL_BIO); |
| 294 | |
| 295 | UVMHIST_LOG(pdhist, "<- done" , 0, 0, 0, 0); |
| 296 | } |
| 297 | |
| 298 | /* |
| 299 | * swaplist functions: functions that operate on the list of swap |
| 300 | * devices on the system. |
| 301 | */ |
| 302 | |
| 303 | /* |
| 304 | * swaplist_insert: insert swap device "sdp" into the global list |
| 305 | * |
| 306 | * => caller must hold both swap_syscall_lock and uvm_swap_data_lock |
| 307 | * => caller must provide a newly allocated swappri structure (we will |
| 308 | * FREE it if we don't need it... this it to prevent allocation |
| 309 | * blocking here while adding swap) |
| 310 | */ |
| 311 | static void |
| 312 | swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) |
| 313 | { |
| 314 | struct swappri *spp, *pspp; |
| 315 | UVMHIST_FUNC("swaplist_insert" ); UVMHIST_CALLED(pdhist); |
| 316 | |
| 317 | /* |
| 318 | * find entry at or after which to insert the new device. |
| 319 | */ |
| 320 | pspp = NULL; |
| 321 | LIST_FOREACH(spp, &swap_priority, spi_swappri) { |
| 322 | if (priority <= spp->spi_priority) |
| 323 | break; |
| 324 | pspp = spp; |
| 325 | } |
| 326 | |
| 327 | /* |
| 328 | * new priority? |
| 329 | */ |
| 330 | if (spp == NULL || spp->spi_priority != priority) { |
| 331 | spp = newspp; /* use newspp! */ |
| 332 | UVMHIST_LOG(pdhist, "created new swappri = %d" , |
| 333 | priority, 0, 0, 0); |
| 334 | |
| 335 | spp->spi_priority = priority; |
| 336 | TAILQ_INIT(&spp->spi_swapdev); |
| 337 | |
| 338 | if (pspp) |
| 339 | LIST_INSERT_AFTER(pspp, spp, spi_swappri); |
| 340 | else |
| 341 | LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); |
| 342 | } else { |
| 343 | /* we don't need a new priority structure, free it */ |
| 344 | kmem_free(newspp, sizeof(*newspp)); |
| 345 | } |
| 346 | |
| 347 | /* |
| 348 | * priority found (or created). now insert on the priority's |
| 349 | * tailq list and bump the total number of swapdevs. |
| 350 | */ |
| 351 | sdp->swd_priority = priority; |
| 352 | TAILQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); |
| 353 | uvmexp.nswapdev++; |
| 354 | } |
| 355 | |
| 356 | /* |
| 357 | * swaplist_find: find and optionally remove a swap device from the |
| 358 | * global list. |
| 359 | * |
| 360 | * => caller must hold both swap_syscall_lock and uvm_swap_data_lock |
| 361 | * => we return the swapdev we found (and removed) |
| 362 | */ |
| 363 | static struct swapdev * |
| 364 | swaplist_find(struct vnode *vp, bool remove) |
| 365 | { |
| 366 | struct swapdev *sdp; |
| 367 | struct swappri *spp; |
| 368 | |
| 369 | /* |
| 370 | * search the lists for the requested vp |
| 371 | */ |
| 372 | |
| 373 | LIST_FOREACH(spp, &swap_priority, spi_swappri) { |
| 374 | TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { |
| 375 | if (sdp->swd_vp == vp) { |
| 376 | if (remove) { |
| 377 | TAILQ_REMOVE(&spp->spi_swapdev, |
| 378 | sdp, swd_next); |
| 379 | uvmexp.nswapdev--; |
| 380 | } |
| 381 | return(sdp); |
| 382 | } |
| 383 | } |
| 384 | } |
| 385 | return (NULL); |
| 386 | } |
| 387 | |
| 388 | /* |
| 389 | * swaplist_trim: scan priority list for empty priority entries and kill |
| 390 | * them. |
| 391 | * |
| 392 | * => caller must hold both swap_syscall_lock and uvm_swap_data_lock |
| 393 | */ |
| 394 | static void |
| 395 | swaplist_trim(void) |
| 396 | { |
| 397 | struct swappri *spp, *nextspp; |
| 398 | |
| 399 | LIST_FOREACH_SAFE(spp, &swap_priority, spi_swappri, nextspp) { |
| 400 | if (!TAILQ_EMPTY(&spp->spi_swapdev)) |
| 401 | continue; |
| 402 | LIST_REMOVE(spp, spi_swappri); |
| 403 | kmem_free(spp, sizeof(*spp)); |
| 404 | } |
| 405 | } |
| 406 | |
| 407 | /* |
| 408 | * swapdrum_getsdp: given a page offset in /dev/drum, convert it back |
| 409 | * to the "swapdev" that maps that section of the drum. |
| 410 | * |
| 411 | * => each swapdev takes one big contig chunk of the drum |
| 412 | * => caller must hold uvm_swap_data_lock |
| 413 | */ |
| 414 | static struct swapdev * |
| 415 | swapdrum_getsdp(int pgno) |
| 416 | { |
| 417 | struct swapdev *sdp; |
| 418 | struct swappri *spp; |
| 419 | |
| 420 | LIST_FOREACH(spp, &swap_priority, spi_swappri) { |
| 421 | TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { |
| 422 | if (sdp->swd_flags & SWF_FAKE) |
| 423 | continue; |
| 424 | if (pgno >= sdp->swd_drumoffset && |
| 425 | pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { |
| 426 | return sdp; |
| 427 | } |
| 428 | } |
| 429 | } |
| 430 | return NULL; |
| 431 | } |
| 432 | |
| 433 | void swapsys_lock(krw_t op) |
| 434 | { |
| 435 | rw_enter(&swap_syscall_lock, op); |
| 436 | } |
| 437 | |
| 438 | void swapsys_unlock(void) |
| 439 | { |
| 440 | rw_exit(&swap_syscall_lock); |
| 441 | } |
| 442 | |
| 443 | /* |
| 444 | * sys_swapctl: main entry point for swapctl(2) system call |
| 445 | * [with two helper functions: swap_on and swap_off] |
| 446 | */ |
| 447 | int |
| 448 | sys_swapctl(struct lwp *l, const struct sys_swapctl_args *uap, register_t *retval) |
| 449 | { |
| 450 | /* { |
| 451 | syscallarg(int) cmd; |
| 452 | syscallarg(void *) arg; |
| 453 | syscallarg(int) misc; |
| 454 | } */ |
| 455 | struct vnode *vp; |
| 456 | struct nameidata nd; |
| 457 | struct swappri *spp; |
| 458 | struct swapdev *sdp; |
| 459 | struct swapent *sep; |
| 460 | #define SWAP_PATH_MAX (PATH_MAX + 1) |
| 461 | char *userpath; |
| 462 | size_t len = 0; |
| 463 | int error, misc; |
| 464 | int priority; |
| 465 | UVMHIST_FUNC("sys_swapctl" ); UVMHIST_CALLED(pdhist); |
| 466 | |
| 467 | /* |
| 468 | * we handle the non-priv NSWAP and STATS request first. |
| 469 | * |
| 470 | * SWAP_NSWAP: return number of config'd swap devices |
| 471 | * [can also be obtained with uvmexp sysctl] |
| 472 | */ |
| 473 | if (SCARG(uap, cmd) == SWAP_NSWAP) { |
| 474 | const int nswapdev = uvmexp.nswapdev; |
| 475 | UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%d" , nswapdev, 0, 0, 0); |
| 476 | *retval = nswapdev; |
| 477 | return 0; |
| 478 | } |
| 479 | |
| 480 | misc = SCARG(uap, misc); |
| 481 | userpath = kmem_alloc(SWAP_PATH_MAX, KM_SLEEP); |
| 482 | |
| 483 | /* |
| 484 | * ensure serialized syscall access by grabbing the swap_syscall_lock |
| 485 | */ |
| 486 | rw_enter(&swap_syscall_lock, RW_WRITER); |
| 487 | |
| 488 | /* |
| 489 | * SWAP_STATS: get stats on current # of configured swap devs |
| 490 | * |
| 491 | * note that the swap_priority list can't change as long |
| 492 | * as we are holding the swap_syscall_lock. we don't want |
| 493 | * to grab the uvm_swap_data_lock because we may fault&sleep during |
| 494 | * copyout() and we don't want to be holding that lock then! |
| 495 | */ |
| 496 | if (SCARG(uap, cmd) == SWAP_STATS |
| 497 | #if defined(COMPAT_50) |
| 498 | || SCARG(uap, cmd) == SWAP_STATS50 |
| 499 | #endif |
| 500 | #if defined(COMPAT_13) |
| 501 | || SCARG(uap, cmd) == SWAP_STATS13 |
| 502 | #endif |
| 503 | ) { |
| 504 | if (misc < 0) { |
| 505 | error = EINVAL; |
| 506 | goto out; |
| 507 | } |
| 508 | if (misc == 0 || uvmexp.nswapdev == 0) { |
| 509 | error = 0; |
| 510 | goto out; |
| 511 | } |
| 512 | /* Make sure userland cannot exhaust kernel memory */ |
| 513 | if ((size_t)misc > (size_t)uvmexp.nswapdev) |
| 514 | misc = uvmexp.nswapdev; |
| 515 | KASSERT(misc > 0); |
| 516 | #if defined(COMPAT_13) |
| 517 | if (SCARG(uap, cmd) == SWAP_STATS13) |
| 518 | len = sizeof(struct swapent13) * misc; |
| 519 | else |
| 520 | #endif |
| 521 | #if defined(COMPAT_50) |
| 522 | if (SCARG(uap, cmd) == SWAP_STATS50) |
| 523 | len = sizeof(struct swapent50) * misc; |
| 524 | else |
| 525 | #endif |
| 526 | len = sizeof(struct swapent) * misc; |
| 527 | sep = (struct swapent *)kmem_alloc(len, KM_SLEEP); |
| 528 | |
| 529 | uvm_swap_stats(SCARG(uap, cmd), sep, misc, retval); |
| 530 | error = copyout(sep, SCARG(uap, arg), len); |
| 531 | |
| 532 | kmem_free(sep, len); |
| 533 | UVMHIST_LOG(pdhist, "<- done SWAP_STATS" , 0, 0, 0, 0); |
| 534 | goto out; |
| 535 | } |
| 536 | if (SCARG(uap, cmd) == SWAP_GETDUMPDEV) { |
| 537 | dev_t *devp = (dev_t *)SCARG(uap, arg); |
| 538 | |
| 539 | error = copyout(&dumpdev, devp, sizeof(dumpdev)); |
| 540 | goto out; |
| 541 | } |
| 542 | |
| 543 | /* |
| 544 | * all other requests require superuser privs. verify. |
| 545 | */ |
| 546 | if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_SWAPCTL, |
| 547 | 0, NULL, NULL, NULL))) |
| 548 | goto out; |
| 549 | |
| 550 | if (SCARG(uap, cmd) == SWAP_DUMPOFF) { |
| 551 | /* drop the current dump device */ |
| 552 | dumpdev = NODEV; |
| 553 | dumpcdev = NODEV; |
| 554 | cpu_dumpconf(); |
| 555 | goto out; |
| 556 | } |
| 557 | |
| 558 | /* |
| 559 | * at this point we expect a path name in arg. we will |
| 560 | * use namei() to gain a vnode reference (vref), and lock |
| 561 | * the vnode (VOP_LOCK). |
| 562 | * |
| 563 | * XXX: a NULL arg means use the root vnode pointer (e.g. for |
| 564 | * miniroot) |
| 565 | */ |
| 566 | if (SCARG(uap, arg) == NULL) { |
| 567 | vp = rootvp; /* miniroot */ |
| 568 | vref(vp); |
| 569 | if (vn_lock(vp, LK_EXCLUSIVE)) { |
| 570 | vrele(vp); |
| 571 | error = EBUSY; |
| 572 | goto out; |
| 573 | } |
| 574 | if (SCARG(uap, cmd) == SWAP_ON && |
| 575 | copystr("miniroot" , userpath, SWAP_PATH_MAX, &len)) |
| 576 | panic("swapctl: miniroot copy failed" ); |
| 577 | } else { |
| 578 | struct pathbuf *pb; |
| 579 | |
| 580 | /* |
| 581 | * This used to allow copying in one extra byte |
| 582 | * (SWAP_PATH_MAX instead of PATH_MAX) for SWAP_ON. |
| 583 | * This was completely pointless because if anyone |
| 584 | * used that extra byte namei would fail with |
| 585 | * ENAMETOOLONG anyway, so I've removed the excess |
| 586 | * logic. - dholland 20100215 |
| 587 | */ |
| 588 | |
| 589 | error = pathbuf_copyin(SCARG(uap, arg), &pb); |
| 590 | if (error) { |
| 591 | goto out; |
| 592 | } |
| 593 | if (SCARG(uap, cmd) == SWAP_ON) { |
| 594 | /* get a copy of the string */ |
| 595 | pathbuf_copystring(pb, userpath, SWAP_PATH_MAX); |
| 596 | len = strlen(userpath) + 1; |
| 597 | } |
| 598 | NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); |
| 599 | if ((error = namei(&nd))) { |
| 600 | pathbuf_destroy(pb); |
| 601 | goto out; |
| 602 | } |
| 603 | vp = nd.ni_vp; |
| 604 | pathbuf_destroy(pb); |
| 605 | } |
| 606 | /* note: "vp" is referenced and locked */ |
| 607 | |
| 608 | error = 0; /* assume no error */ |
| 609 | switch(SCARG(uap, cmd)) { |
| 610 | |
| 611 | case SWAP_DUMPDEV: |
| 612 | if (vp->v_type != VBLK) { |
| 613 | error = ENOTBLK; |
| 614 | break; |
| 615 | } |
| 616 | if (bdevsw_lookup(vp->v_rdev)) { |
| 617 | dumpdev = vp->v_rdev; |
| 618 | dumpcdev = devsw_blk2chr(dumpdev); |
| 619 | } else |
| 620 | dumpdev = NODEV; |
| 621 | cpu_dumpconf(); |
| 622 | break; |
| 623 | |
| 624 | case SWAP_CTL: |
| 625 | /* |
| 626 | * get new priority, remove old entry (if any) and then |
| 627 | * reinsert it in the correct place. finally, prune out |
| 628 | * any empty priority structures. |
| 629 | */ |
| 630 | priority = SCARG(uap, misc); |
| 631 | spp = kmem_alloc(sizeof(*spp), KM_SLEEP); |
| 632 | mutex_enter(&uvm_swap_data_lock); |
| 633 | if ((sdp = swaplist_find(vp, true)) == NULL) { |
| 634 | error = ENOENT; |
| 635 | } else { |
| 636 | swaplist_insert(sdp, spp, priority); |
| 637 | swaplist_trim(); |
| 638 | } |
| 639 | mutex_exit(&uvm_swap_data_lock); |
| 640 | if (error) |
| 641 | kmem_free(spp, sizeof(*spp)); |
| 642 | break; |
| 643 | |
| 644 | case SWAP_ON: |
| 645 | |
| 646 | /* |
| 647 | * check for duplicates. if none found, then insert a |
| 648 | * dummy entry on the list to prevent someone else from |
| 649 | * trying to enable this device while we are working on |
| 650 | * it. |
| 651 | */ |
| 652 | |
| 653 | priority = SCARG(uap, misc); |
| 654 | sdp = kmem_zalloc(sizeof(*sdp), KM_SLEEP); |
| 655 | spp = kmem_alloc(sizeof(*spp), KM_SLEEP); |
| 656 | sdp->swd_flags = SWF_FAKE; |
| 657 | sdp->swd_vp = vp; |
| 658 | sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; |
| 659 | bufq_alloc(&sdp->swd_tab, "disksort" , BUFQ_SORT_RAWBLOCK); |
| 660 | mutex_enter(&uvm_swap_data_lock); |
| 661 | if (swaplist_find(vp, false) != NULL) { |
| 662 | error = EBUSY; |
| 663 | mutex_exit(&uvm_swap_data_lock); |
| 664 | bufq_free(sdp->swd_tab); |
| 665 | kmem_free(sdp, sizeof(*sdp)); |
| 666 | kmem_free(spp, sizeof(*spp)); |
| 667 | break; |
| 668 | } |
| 669 | swaplist_insert(sdp, spp, priority); |
| 670 | mutex_exit(&uvm_swap_data_lock); |
| 671 | |
| 672 | KASSERT(len > 0); |
| 673 | sdp->swd_pathlen = len; |
| 674 | sdp->swd_path = kmem_alloc(len, KM_SLEEP); |
| 675 | if (copystr(userpath, sdp->swd_path, len, 0) != 0) |
| 676 | panic("swapctl: copystr" ); |
| 677 | |
| 678 | /* |
| 679 | * we've now got a FAKE placeholder in the swap list. |
| 680 | * now attempt to enable swap on it. if we fail, undo |
| 681 | * what we've done and kill the fake entry we just inserted. |
| 682 | * if swap_on is a success, it will clear the SWF_FAKE flag |
| 683 | */ |
| 684 | |
| 685 | if ((error = swap_on(l, sdp)) != 0) { |
| 686 | mutex_enter(&uvm_swap_data_lock); |
| 687 | (void) swaplist_find(vp, true); /* kill fake entry */ |
| 688 | swaplist_trim(); |
| 689 | mutex_exit(&uvm_swap_data_lock); |
| 690 | bufq_free(sdp->swd_tab); |
| 691 | kmem_free(sdp->swd_path, sdp->swd_pathlen); |
| 692 | kmem_free(sdp, sizeof(*sdp)); |
| 693 | break; |
| 694 | } |
| 695 | break; |
| 696 | |
| 697 | case SWAP_OFF: |
| 698 | mutex_enter(&uvm_swap_data_lock); |
| 699 | if ((sdp = swaplist_find(vp, false)) == NULL) { |
| 700 | mutex_exit(&uvm_swap_data_lock); |
| 701 | error = ENXIO; |
| 702 | break; |
| 703 | } |
| 704 | |
| 705 | /* |
| 706 | * If a device isn't in use or enabled, we |
| 707 | * can't stop swapping from it (again). |
| 708 | */ |
| 709 | if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { |
| 710 | mutex_exit(&uvm_swap_data_lock); |
| 711 | error = EBUSY; |
| 712 | break; |
| 713 | } |
| 714 | |
| 715 | /* |
| 716 | * do the real work. |
| 717 | */ |
| 718 | error = swap_off(l, sdp); |
| 719 | break; |
| 720 | |
| 721 | default: |
| 722 | error = EINVAL; |
| 723 | } |
| 724 | |
| 725 | /* |
| 726 | * done! release the ref gained by namei() and unlock. |
| 727 | */ |
| 728 | vput(vp); |
| 729 | out: |
| 730 | rw_exit(&swap_syscall_lock); |
| 731 | kmem_free(userpath, SWAP_PATH_MAX); |
| 732 | |
| 733 | UVMHIST_LOG(pdhist, "<- done! error=%d" , error, 0, 0, 0); |
| 734 | return (error); |
| 735 | } |
| 736 | |
| 737 | /* |
| 738 | * uvm_swap_stats: implements swapctl(SWAP_STATS). The function is kept |
| 739 | * away from sys_swapctl() in order to allow COMPAT_* swapctl() |
| 740 | * emulation to use it directly without going through sys_swapctl(). |
| 741 | * The problem with using sys_swapctl() there is that it involves |
| 742 | * copying the swapent array to the stackgap, and this array's size |
| 743 | * is not known at build time. Hence it would not be possible to |
| 744 | * ensure it would fit in the stackgap in any case. |
| 745 | */ |
| 746 | void |
| 747 | uvm_swap_stats(int cmd, struct swapent *sep, int sec, register_t *retval) |
| 748 | { |
| 749 | struct swappri *spp; |
| 750 | struct swapdev *sdp; |
| 751 | int count = 0; |
| 752 | |
| 753 | KASSERT(rw_lock_held(&swap_syscall_lock)); |
| 754 | |
| 755 | LIST_FOREACH(spp, &swap_priority, spi_swappri) { |
| 756 | TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { |
| 757 | int inuse; |
| 758 | |
| 759 | if (sec-- <= 0) |
| 760 | break; |
| 761 | |
| 762 | /* |
| 763 | * backwards compatibility for system call. |
| 764 | * For NetBSD 1.3 and 5.0, we have to use |
| 765 | * the 32 bit dev_t. For 5.0 and -current |
| 766 | * we have to add the path. |
| 767 | */ |
| 768 | inuse = btodb((uint64_t)sdp->swd_npginuse << |
| 769 | PAGE_SHIFT); |
| 770 | |
| 771 | #if defined(COMPAT_13) || defined(COMPAT_50) |
| 772 | if (cmd == SWAP_STATS) { |
| 773 | #endif |
| 774 | sep->se_dev = sdp->swd_dev; |
| 775 | sep->se_flags = sdp->swd_flags; |
| 776 | sep->se_nblks = sdp->swd_nblks; |
| 777 | sep->se_inuse = inuse; |
| 778 | sep->se_priority = sdp->swd_priority; |
| 779 | KASSERT(sdp->swd_pathlen < |
| 780 | sizeof(sep->se_path)); |
| 781 | strcpy(sep->se_path, sdp->swd_path); |
| 782 | sep++; |
| 783 | #if defined(COMPAT_13) |
| 784 | } else if (cmd == SWAP_STATS13) { |
| 785 | struct swapent13 *sep13 = |
| 786 | (struct swapent13 *)sep; |
| 787 | |
| 788 | sep13->se13_dev = sdp->swd_dev; |
| 789 | sep13->se13_flags = sdp->swd_flags; |
| 790 | sep13->se13_nblks = sdp->swd_nblks; |
| 791 | sep13->se13_inuse = inuse; |
| 792 | sep13->se13_priority = sdp->swd_priority; |
| 793 | sep = (struct swapent *)(sep13 + 1); |
| 794 | #endif |
| 795 | #if defined(COMPAT_50) |
| 796 | } else if (cmd == SWAP_STATS50) { |
| 797 | struct swapent50 *sep50 = |
| 798 | (struct swapent50 *)sep; |
| 799 | |
| 800 | sep50->se50_dev = sdp->swd_dev; |
| 801 | sep50->se50_flags = sdp->swd_flags; |
| 802 | sep50->se50_nblks = sdp->swd_nblks; |
| 803 | sep50->se50_inuse = inuse; |
| 804 | sep50->se50_priority = sdp->swd_priority; |
| 805 | KASSERT(sdp->swd_pathlen < |
| 806 | sizeof(sep50->se50_path)); |
| 807 | strcpy(sep50->se50_path, sdp->swd_path); |
| 808 | sep = (struct swapent *)(sep50 + 1); |
| 809 | #endif |
| 810 | #if defined(COMPAT_13) || defined(COMPAT_50) |
| 811 | } |
| 812 | #endif |
| 813 | count++; |
| 814 | } |
| 815 | } |
| 816 | *retval = count; |
| 817 | } |
| 818 | |
| 819 | /* |
| 820 | * swap_on: attempt to enable a swapdev for swapping. note that the |
| 821 | * swapdev is already on the global list, but disabled (marked |
| 822 | * SWF_FAKE). |
| 823 | * |
| 824 | * => we avoid the start of the disk (to protect disk labels) |
| 825 | * => we also avoid the miniroot, if we are swapping to root. |
| 826 | * => caller should leave uvm_swap_data_lock unlocked, we may lock it |
| 827 | * if needed. |
| 828 | */ |
| 829 | static int |
| 830 | swap_on(struct lwp *l, struct swapdev *sdp) |
| 831 | { |
| 832 | struct vnode *vp; |
| 833 | int error, npages, nblocks, size; |
| 834 | long addr; |
| 835 | vmem_addr_t result; |
| 836 | struct vattr va; |
| 837 | dev_t dev; |
| 838 | UVMHIST_FUNC("swap_on" ); UVMHIST_CALLED(pdhist); |
| 839 | |
| 840 | /* |
| 841 | * we want to enable swapping on sdp. the swd_vp contains |
| 842 | * the vnode we want (locked and ref'd), and the swd_dev |
| 843 | * contains the dev_t of the file, if it a block device. |
| 844 | */ |
| 845 | |
| 846 | vp = sdp->swd_vp; |
| 847 | dev = sdp->swd_dev; |
| 848 | |
| 849 | /* |
| 850 | * open the swap file (mostly useful for block device files to |
| 851 | * let device driver know what is up). |
| 852 | * |
| 853 | * we skip the open/close for root on swap because the root |
| 854 | * has already been opened when root was mounted (mountroot). |
| 855 | */ |
| 856 | if (vp != rootvp) { |
| 857 | if ((error = VOP_OPEN(vp, FREAD|FWRITE, l->l_cred))) |
| 858 | return (error); |
| 859 | } |
| 860 | |
| 861 | /* XXX this only works for block devices */ |
| 862 | UVMHIST_LOG(pdhist, " dev=%d, major(dev)=%d" , dev, major(dev), 0,0); |
| 863 | |
| 864 | /* |
| 865 | * we now need to determine the size of the swap area. for |
| 866 | * block specials we can call the d_psize function. |
| 867 | * for normal files, we must stat [get attrs]. |
| 868 | * |
| 869 | * we put the result in nblks. |
| 870 | * for normal files, we also want the filesystem block size |
| 871 | * (which we get with statfs). |
| 872 | */ |
| 873 | switch (vp->v_type) { |
| 874 | case VBLK: |
| 875 | if ((nblocks = bdev_size(dev)) == -1) { |
| 876 | error = ENXIO; |
| 877 | goto bad; |
| 878 | } |
| 879 | break; |
| 880 | |
| 881 | case VREG: |
| 882 | if ((error = VOP_GETATTR(vp, &va, l->l_cred))) |
| 883 | goto bad; |
| 884 | nblocks = (int)btodb(va.va_size); |
| 885 | sdp->swd_bsize = 1 << vp->v_mount->mnt_fs_bshift; |
| 886 | /* |
| 887 | * limit the max # of outstanding I/O requests we issue |
| 888 | * at any one time. take it easy on NFS servers. |
| 889 | */ |
| 890 | if (vp->v_tag == VT_NFS) |
| 891 | sdp->swd_maxactive = 2; /* XXX */ |
| 892 | else |
| 893 | sdp->swd_maxactive = 8; /* XXX */ |
| 894 | break; |
| 895 | |
| 896 | default: |
| 897 | error = ENXIO; |
| 898 | goto bad; |
| 899 | } |
| 900 | |
| 901 | /* |
| 902 | * save nblocks in a safe place and convert to pages. |
| 903 | */ |
| 904 | |
| 905 | sdp->swd_nblks = nblocks; |
| 906 | npages = dbtob((uint64_t)nblocks) >> PAGE_SHIFT; |
| 907 | |
| 908 | /* |
| 909 | * for block special files, we want to make sure that leave |
| 910 | * the disklabel and bootblocks alone, so we arrange to skip |
| 911 | * over them (arbitrarily choosing to skip PAGE_SIZE bytes). |
| 912 | * note that because of this the "size" can be less than the |
| 913 | * actual number of blocks on the device. |
| 914 | */ |
| 915 | if (vp->v_type == VBLK) { |
| 916 | /* we use pages 1 to (size - 1) [inclusive] */ |
| 917 | size = npages - 1; |
| 918 | addr = 1; |
| 919 | } else { |
| 920 | /* we use pages 0 to (size - 1) [inclusive] */ |
| 921 | size = npages; |
| 922 | addr = 0; |
| 923 | } |
| 924 | |
| 925 | /* |
| 926 | * make sure we have enough blocks for a reasonable sized swap |
| 927 | * area. we want at least one page. |
| 928 | */ |
| 929 | |
| 930 | if (size < 1) { |
| 931 | UVMHIST_LOG(pdhist, " size <= 1!!" , 0, 0, 0, 0); |
| 932 | error = EINVAL; |
| 933 | goto bad; |
| 934 | } |
| 935 | |
| 936 | UVMHIST_LOG(pdhist, " dev=%x: size=%d addr=%ld" , dev, size, addr, 0); |
| 937 | |
| 938 | /* |
| 939 | * now we need to allocate an extent to manage this swap device |
| 940 | */ |
| 941 | |
| 942 | sdp->swd_blist = blist_create(npages); |
| 943 | /* mark all expect the `saved' region free. */ |
| 944 | blist_free(sdp->swd_blist, addr, size); |
| 945 | |
| 946 | /* |
| 947 | * if the vnode we are swapping to is the root vnode |
| 948 | * (i.e. we are swapping to the miniroot) then we want |
| 949 | * to make sure we don't overwrite it. do a statfs to |
| 950 | * find its size and skip over it. |
| 951 | */ |
| 952 | if (vp == rootvp) { |
| 953 | struct mount *mp; |
| 954 | struct statvfs *sp; |
| 955 | int rootblocks, rootpages; |
| 956 | |
| 957 | mp = rootvnode->v_mount; |
| 958 | sp = &mp->mnt_stat; |
| 959 | rootblocks = sp->f_blocks * btodb(sp->f_frsize); |
| 960 | /* |
| 961 | * XXX: sp->f_blocks isn't the total number of |
| 962 | * blocks in the filesystem, it's the number of |
| 963 | * data blocks. so, our rootblocks almost |
| 964 | * definitely underestimates the total size |
| 965 | * of the filesystem - how badly depends on the |
| 966 | * details of the filesystem type. there isn't |
| 967 | * an obvious way to deal with this cleanly |
| 968 | * and perfectly, so for now we just pad our |
| 969 | * rootblocks estimate with an extra 5 percent. |
| 970 | */ |
| 971 | rootblocks += (rootblocks >> 5) + |
| 972 | (rootblocks >> 6) + |
| 973 | (rootblocks >> 7); |
| 974 | rootpages = round_page(dbtob(rootblocks)) >> PAGE_SHIFT; |
| 975 | if (rootpages > size) |
| 976 | panic("swap_on: miniroot larger than swap?" ); |
| 977 | |
| 978 | if (rootpages != blist_fill(sdp->swd_blist, addr, rootpages)) { |
| 979 | panic("swap_on: unable to preserve miniroot" ); |
| 980 | } |
| 981 | |
| 982 | size -= rootpages; |
| 983 | printf("Preserved %d pages of miniroot " , rootpages); |
| 984 | printf("leaving %d pages of swap\n" , size); |
| 985 | } |
| 986 | |
| 987 | /* |
| 988 | * add a ref to vp to reflect usage as a swap device. |
| 989 | */ |
| 990 | vref(vp); |
| 991 | |
| 992 | /* |
| 993 | * now add the new swapdev to the drum and enable. |
| 994 | */ |
| 995 | error = vmem_alloc(swapmap, npages, VM_BESTFIT | VM_SLEEP, &result); |
| 996 | if (error != 0) |
| 997 | panic("swapdrum_add" ); |
| 998 | /* |
| 999 | * If this is the first regular swap create the workqueue. |
| 1000 | * => Protected by swap_syscall_lock. |
| 1001 | */ |
| 1002 | if (vp->v_type != VBLK) { |
| 1003 | if (sw_reg_count++ == 0) { |
| 1004 | KASSERT(sw_reg_workqueue == NULL); |
| 1005 | if (workqueue_create(&sw_reg_workqueue, "swapiod" , |
| 1006 | sw_reg_iodone, NULL, PRIBIO, IPL_BIO, 0) != 0) |
| 1007 | panic("%s: workqueue_create failed" , __func__); |
| 1008 | } |
| 1009 | } |
| 1010 | |
| 1011 | sdp->swd_drumoffset = (int)result; |
| 1012 | sdp->swd_drumsize = npages; |
| 1013 | sdp->swd_npages = size; |
| 1014 | mutex_enter(&uvm_swap_data_lock); |
| 1015 | sdp->swd_flags &= ~SWF_FAKE; /* going live */ |
| 1016 | sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); |
| 1017 | uvmexp.swpages += size; |
| 1018 | uvmexp.swpgavail += size; |
| 1019 | mutex_exit(&uvm_swap_data_lock); |
| 1020 | return (0); |
| 1021 | |
| 1022 | /* |
| 1023 | * failure: clean up and return error. |
| 1024 | */ |
| 1025 | |
| 1026 | bad: |
| 1027 | if (sdp->swd_blist) { |
| 1028 | blist_destroy(sdp->swd_blist); |
| 1029 | } |
| 1030 | if (vp != rootvp) { |
| 1031 | (void)VOP_CLOSE(vp, FREAD|FWRITE, l->l_cred); |
| 1032 | } |
| 1033 | return (error); |
| 1034 | } |
| 1035 | |
| 1036 | /* |
| 1037 | * swap_off: stop swapping on swapdev |
| 1038 | * |
| 1039 | * => swap data should be locked, we will unlock. |
| 1040 | */ |
| 1041 | static int |
| 1042 | swap_off(struct lwp *l, struct swapdev *sdp) |
| 1043 | { |
| 1044 | int npages = sdp->swd_npages; |
| 1045 | int error = 0; |
| 1046 | |
| 1047 | UVMHIST_FUNC("swap_off" ); UVMHIST_CALLED(pdhist); |
| 1048 | UVMHIST_LOG(pdhist, " dev=%x, npages=%d" , sdp->swd_dev,npages,0,0); |
| 1049 | |
| 1050 | /* disable the swap area being removed */ |
| 1051 | sdp->swd_flags &= ~SWF_ENABLE; |
| 1052 | uvmexp.swpgavail -= npages; |
| 1053 | mutex_exit(&uvm_swap_data_lock); |
| 1054 | |
| 1055 | /* |
| 1056 | * the idea is to find all the pages that are paged out to this |
| 1057 | * device, and page them all in. in uvm, swap-backed pageable |
| 1058 | * memory can take two forms: aobjs and anons. call the |
| 1059 | * swapoff hook for each subsystem to bring in pages. |
| 1060 | */ |
| 1061 | |
| 1062 | if (uao_swap_off(sdp->swd_drumoffset, |
| 1063 | sdp->swd_drumoffset + sdp->swd_drumsize) || |
| 1064 | amap_swap_off(sdp->swd_drumoffset, |
| 1065 | sdp->swd_drumoffset + sdp->swd_drumsize)) { |
| 1066 | error = ENOMEM; |
| 1067 | } else if (sdp->swd_npginuse > sdp->swd_npgbad) { |
| 1068 | error = EBUSY; |
| 1069 | } |
| 1070 | |
| 1071 | if (error) { |
| 1072 | mutex_enter(&uvm_swap_data_lock); |
| 1073 | sdp->swd_flags |= SWF_ENABLE; |
| 1074 | uvmexp.swpgavail += npages; |
| 1075 | mutex_exit(&uvm_swap_data_lock); |
| 1076 | |
| 1077 | return error; |
| 1078 | } |
| 1079 | |
| 1080 | /* |
| 1081 | * If this is the last regular swap destroy the workqueue. |
| 1082 | * => Protected by swap_syscall_lock. |
| 1083 | */ |
| 1084 | if (sdp->swd_vp->v_type != VBLK) { |
| 1085 | KASSERT(sw_reg_count > 0); |
| 1086 | KASSERT(sw_reg_workqueue != NULL); |
| 1087 | if (--sw_reg_count == 0) { |
| 1088 | workqueue_destroy(sw_reg_workqueue); |
| 1089 | sw_reg_workqueue = NULL; |
| 1090 | } |
| 1091 | } |
| 1092 | |
| 1093 | /* |
| 1094 | * done with the vnode. |
| 1095 | * drop our ref on the vnode before calling VOP_CLOSE() |
| 1096 | * so that spec_close() can tell if this is the last close. |
| 1097 | */ |
| 1098 | vrele(sdp->swd_vp); |
| 1099 | if (sdp->swd_vp != rootvp) { |
| 1100 | (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, l->l_cred); |
| 1101 | } |
| 1102 | |
| 1103 | mutex_enter(&uvm_swap_data_lock); |
| 1104 | uvmexp.swpages -= npages; |
| 1105 | uvmexp.swpginuse -= sdp->swd_npgbad; |
| 1106 | |
| 1107 | if (swaplist_find(sdp->swd_vp, true) == NULL) |
| 1108 | panic("%s: swapdev not in list" , __func__); |
| 1109 | swaplist_trim(); |
| 1110 | mutex_exit(&uvm_swap_data_lock); |
| 1111 | |
| 1112 | /* |
| 1113 | * free all resources! |
| 1114 | */ |
| 1115 | vmem_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize); |
| 1116 | blist_destroy(sdp->swd_blist); |
| 1117 | bufq_free(sdp->swd_tab); |
| 1118 | kmem_free(sdp, sizeof(*sdp)); |
| 1119 | return (0); |
| 1120 | } |
| 1121 | |
| 1122 | void |
| 1123 | uvm_swap_shutdown(struct lwp *l) |
| 1124 | { |
| 1125 | struct swapdev *sdp; |
| 1126 | struct swappri *spp; |
| 1127 | struct vnode *vp; |
| 1128 | int error; |
| 1129 | |
| 1130 | printf("turning of swap..." ); |
| 1131 | rw_enter(&swap_syscall_lock, RW_WRITER); |
| 1132 | mutex_enter(&uvm_swap_data_lock); |
| 1133 | again: |
| 1134 | LIST_FOREACH(spp, &swap_priority, spi_swappri) |
| 1135 | TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { |
| 1136 | if (sdp->swd_flags & SWF_FAKE) |
| 1137 | continue; |
| 1138 | if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) |
| 1139 | continue; |
| 1140 | #ifdef DEBUG |
| 1141 | printf("\nturning off swap on %s..." , |
| 1142 | sdp->swd_path); |
| 1143 | #endif |
| 1144 | if (vn_lock(vp = sdp->swd_vp, LK_EXCLUSIVE)) { |
| 1145 | error = EBUSY; |
| 1146 | vp = NULL; |
| 1147 | } else |
| 1148 | error = 0; |
| 1149 | if (!error) { |
| 1150 | error = swap_off(l, sdp); |
| 1151 | mutex_enter(&uvm_swap_data_lock); |
| 1152 | } |
| 1153 | if (error) { |
| 1154 | printf("stopping swap on %s failed " |
| 1155 | "with error %d\n" , sdp->swd_path, error); |
| 1156 | TAILQ_REMOVE(&spp->spi_swapdev, sdp, |
| 1157 | swd_next); |
| 1158 | uvmexp.nswapdev--; |
| 1159 | swaplist_trim(); |
| 1160 | if (vp) |
| 1161 | vput(vp); |
| 1162 | } |
| 1163 | goto again; |
| 1164 | } |
| 1165 | printf(" done\n" ); |
| 1166 | mutex_exit(&uvm_swap_data_lock); |
| 1167 | rw_exit(&swap_syscall_lock); |
| 1168 | } |
| 1169 | |
| 1170 | |
| 1171 | /* |
| 1172 | * /dev/drum interface and i/o functions |
| 1173 | */ |
| 1174 | |
| 1175 | /* |
| 1176 | * swstrategy: perform I/O on the drum |
| 1177 | * |
| 1178 | * => we must map the i/o request from the drum to the correct swapdev. |
| 1179 | */ |
| 1180 | static void |
| 1181 | swstrategy(struct buf *bp) |
| 1182 | { |
| 1183 | struct swapdev *sdp; |
| 1184 | struct vnode *vp; |
| 1185 | int pageno, bn; |
| 1186 | UVMHIST_FUNC("swstrategy" ); UVMHIST_CALLED(pdhist); |
| 1187 | |
| 1188 | /* |
| 1189 | * convert block number to swapdev. note that swapdev can't |
| 1190 | * be yanked out from under us because we are holding resources |
| 1191 | * in it (i.e. the blocks we are doing I/O on). |
| 1192 | */ |
| 1193 | pageno = dbtob((int64_t)bp->b_blkno) >> PAGE_SHIFT; |
| 1194 | mutex_enter(&uvm_swap_data_lock); |
| 1195 | sdp = swapdrum_getsdp(pageno); |
| 1196 | mutex_exit(&uvm_swap_data_lock); |
| 1197 | if (sdp == NULL) { |
| 1198 | bp->b_error = EINVAL; |
| 1199 | bp->b_resid = bp->b_bcount; |
| 1200 | biodone(bp); |
| 1201 | UVMHIST_LOG(pdhist, " failed to get swap device" , 0, 0, 0, 0); |
| 1202 | return; |
| 1203 | } |
| 1204 | |
| 1205 | /* |
| 1206 | * convert drum page number to block number on this swapdev. |
| 1207 | */ |
| 1208 | |
| 1209 | pageno -= sdp->swd_drumoffset; /* page # on swapdev */ |
| 1210 | bn = btodb((uint64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ |
| 1211 | |
| 1212 | UVMHIST_LOG(pdhist, " %s: mapoff=%x bn=%x bcount=%ld" , |
| 1213 | ((bp->b_flags & B_READ) == 0) ? "write" : "read" , |
| 1214 | sdp->swd_drumoffset, bn, bp->b_bcount); |
| 1215 | |
| 1216 | /* |
| 1217 | * for block devices we finish up here. |
| 1218 | * for regular files we have to do more work which we delegate |
| 1219 | * to sw_reg_strategy(). |
| 1220 | */ |
| 1221 | |
| 1222 | vp = sdp->swd_vp; /* swapdev vnode pointer */ |
| 1223 | switch (vp->v_type) { |
| 1224 | default: |
| 1225 | panic("%s: vnode type 0x%x" , __func__, vp->v_type); |
| 1226 | |
| 1227 | case VBLK: |
| 1228 | |
| 1229 | /* |
| 1230 | * must convert "bp" from an I/O on /dev/drum to an I/O |
| 1231 | * on the swapdev (sdp). |
| 1232 | */ |
| 1233 | bp->b_blkno = bn; /* swapdev block number */ |
| 1234 | bp->b_dev = sdp->swd_dev; /* swapdev dev_t */ |
| 1235 | |
| 1236 | /* |
| 1237 | * if we are doing a write, we have to redirect the i/o on |
| 1238 | * drum's v_numoutput counter to the swapdevs. |
| 1239 | */ |
| 1240 | if ((bp->b_flags & B_READ) == 0) { |
| 1241 | mutex_enter(bp->b_objlock); |
| 1242 | vwakeup(bp); /* kills one 'v_numoutput' on drum */ |
| 1243 | mutex_exit(bp->b_objlock); |
| 1244 | mutex_enter(vp->v_interlock); |
| 1245 | vp->v_numoutput++; /* put it on swapdev */ |
| 1246 | mutex_exit(vp->v_interlock); |
| 1247 | } |
| 1248 | |
| 1249 | /* |
| 1250 | * finally plug in swapdev vnode and start I/O |
| 1251 | */ |
| 1252 | bp->b_vp = vp; |
| 1253 | bp->b_objlock = vp->v_interlock; |
| 1254 | VOP_STRATEGY(vp, bp); |
| 1255 | return; |
| 1256 | |
| 1257 | case VREG: |
| 1258 | /* |
| 1259 | * delegate to sw_reg_strategy function. |
| 1260 | */ |
| 1261 | sw_reg_strategy(sdp, bp, bn); |
| 1262 | return; |
| 1263 | } |
| 1264 | /* NOTREACHED */ |
| 1265 | } |
| 1266 | |
| 1267 | /* |
| 1268 | * swread: the read function for the drum (just a call to physio) |
| 1269 | */ |
| 1270 | /*ARGSUSED*/ |
| 1271 | static int |
| 1272 | swread(dev_t dev, struct uio *uio, int ioflag) |
| 1273 | { |
| 1274 | UVMHIST_FUNC("swread" ); UVMHIST_CALLED(pdhist); |
| 1275 | |
| 1276 | UVMHIST_LOG(pdhist, " dev=%x offset=%qx" , dev, uio->uio_offset, 0, 0); |
| 1277 | return (physio(swstrategy, NULL, dev, B_READ, minphys, uio)); |
| 1278 | } |
| 1279 | |
| 1280 | /* |
| 1281 | * swwrite: the write function for the drum (just a call to physio) |
| 1282 | */ |
| 1283 | /*ARGSUSED*/ |
| 1284 | static int |
| 1285 | swwrite(dev_t dev, struct uio *uio, int ioflag) |
| 1286 | { |
| 1287 | UVMHIST_FUNC("swwrite" ); UVMHIST_CALLED(pdhist); |
| 1288 | |
| 1289 | UVMHIST_LOG(pdhist, " dev=%x offset=%qx" , dev, uio->uio_offset, 0, 0); |
| 1290 | return (physio(swstrategy, NULL, dev, B_WRITE, minphys, uio)); |
| 1291 | } |
| 1292 | |
| 1293 | const struct bdevsw swap_bdevsw = { |
| 1294 | .d_open = nullopen, |
| 1295 | .d_close = nullclose, |
| 1296 | .d_strategy = swstrategy, |
| 1297 | .d_ioctl = noioctl, |
| 1298 | .d_dump = nodump, |
| 1299 | .d_psize = nosize, |
| 1300 | .d_discard = nodiscard, |
| 1301 | .d_flag = D_OTHER |
| 1302 | }; |
| 1303 | |
| 1304 | const struct cdevsw swap_cdevsw = { |
| 1305 | .d_open = nullopen, |
| 1306 | .d_close = nullclose, |
| 1307 | .d_read = swread, |
| 1308 | .d_write = swwrite, |
| 1309 | .d_ioctl = noioctl, |
| 1310 | .d_stop = nostop, |
| 1311 | .d_tty = notty, |
| 1312 | .d_poll = nopoll, |
| 1313 | .d_mmap = nommap, |
| 1314 | .d_kqfilter = nokqfilter, |
| 1315 | .d_discard = nodiscard, |
| 1316 | .d_flag = D_OTHER, |
| 1317 | }; |
| 1318 | |
| 1319 | /* |
| 1320 | * sw_reg_strategy: handle swap i/o to regular files |
| 1321 | */ |
| 1322 | static void |
| 1323 | sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) |
| 1324 | { |
| 1325 | struct vnode *vp; |
| 1326 | struct vndxfer *vnx; |
| 1327 | daddr_t nbn; |
| 1328 | char *addr; |
| 1329 | off_t byteoff; |
| 1330 | int s, off, nra, error, sz, resid; |
| 1331 | UVMHIST_FUNC("sw_reg_strategy" ); UVMHIST_CALLED(pdhist); |
| 1332 | |
| 1333 | /* |
| 1334 | * allocate a vndxfer head for this transfer and point it to |
| 1335 | * our buffer. |
| 1336 | */ |
| 1337 | vnx = pool_get(&vndxfer_pool, PR_WAITOK); |
| 1338 | vnx->vx_flags = VX_BUSY; |
| 1339 | vnx->vx_error = 0; |
| 1340 | vnx->vx_pending = 0; |
| 1341 | vnx->vx_bp = bp; |
| 1342 | vnx->vx_sdp = sdp; |
| 1343 | |
| 1344 | /* |
| 1345 | * setup for main loop where we read filesystem blocks into |
| 1346 | * our buffer. |
| 1347 | */ |
| 1348 | error = 0; |
| 1349 | bp->b_resid = bp->b_bcount; /* nothing transfered yet! */ |
| 1350 | addr = bp->b_data; /* current position in buffer */ |
| 1351 | byteoff = dbtob((uint64_t)bn); |
| 1352 | |
| 1353 | for (resid = bp->b_resid; resid; resid -= sz) { |
| 1354 | struct vndbuf *nbp; |
| 1355 | |
| 1356 | /* |
| 1357 | * translate byteoffset into block number. return values: |
| 1358 | * vp = vnode of underlying device |
| 1359 | * nbn = new block number (on underlying vnode dev) |
| 1360 | * nra = num blocks we can read-ahead (excludes requested |
| 1361 | * block) |
| 1362 | */ |
| 1363 | nra = 0; |
| 1364 | error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, |
| 1365 | &vp, &nbn, &nra); |
| 1366 | |
| 1367 | if (error == 0 && nbn == (daddr_t)-1) { |
| 1368 | /* |
| 1369 | * this used to just set error, but that doesn't |
| 1370 | * do the right thing. Instead, it causes random |
| 1371 | * memory errors. The panic() should remain until |
| 1372 | * this condition doesn't destabilize the system. |
| 1373 | */ |
| 1374 | #if 1 |
| 1375 | panic("%s: swap to sparse file" , __func__); |
| 1376 | #else |
| 1377 | error = EIO; /* failure */ |
| 1378 | #endif |
| 1379 | } |
| 1380 | |
| 1381 | /* |
| 1382 | * punt if there was an error or a hole in the file. |
| 1383 | * we must wait for any i/o ops we have already started |
| 1384 | * to finish before returning. |
| 1385 | * |
| 1386 | * XXX we could deal with holes here but it would be |
| 1387 | * a hassle (in the write case). |
| 1388 | */ |
| 1389 | if (error) { |
| 1390 | s = splbio(); |
| 1391 | vnx->vx_error = error; /* pass error up */ |
| 1392 | goto out; |
| 1393 | } |
| 1394 | |
| 1395 | /* |
| 1396 | * compute the size ("sz") of this transfer (in bytes). |
| 1397 | */ |
| 1398 | off = byteoff % sdp->swd_bsize; |
| 1399 | sz = (1 + nra) * sdp->swd_bsize - off; |
| 1400 | if (sz > resid) |
| 1401 | sz = resid; |
| 1402 | |
| 1403 | UVMHIST_LOG(pdhist, "sw_reg_strategy: " |
| 1404 | "vp %p/%p offset 0x%x/0x%x" , |
| 1405 | sdp->swd_vp, vp, byteoff, nbn); |
| 1406 | |
| 1407 | /* |
| 1408 | * now get a buf structure. note that the vb_buf is |
| 1409 | * at the front of the nbp structure so that you can |
| 1410 | * cast pointers between the two structure easily. |
| 1411 | */ |
| 1412 | nbp = pool_get(&vndbuf_pool, PR_WAITOK); |
| 1413 | buf_init(&nbp->vb_buf); |
| 1414 | nbp->vb_buf.b_flags = bp->b_flags; |
| 1415 | nbp->vb_buf.b_cflags = bp->b_cflags; |
| 1416 | nbp->vb_buf.b_oflags = bp->b_oflags; |
| 1417 | nbp->vb_buf.b_bcount = sz; |
| 1418 | nbp->vb_buf.b_bufsize = sz; |
| 1419 | nbp->vb_buf.b_error = 0; |
| 1420 | nbp->vb_buf.b_data = addr; |
| 1421 | nbp->vb_buf.b_lblkno = 0; |
| 1422 | nbp->vb_buf.b_blkno = nbn + btodb(off); |
| 1423 | nbp->vb_buf.b_rawblkno = nbp->vb_buf.b_blkno; |
| 1424 | nbp->vb_buf.b_iodone = sw_reg_biodone; |
| 1425 | nbp->vb_buf.b_vp = vp; |
| 1426 | nbp->vb_buf.b_objlock = vp->v_interlock; |
| 1427 | if (vp->v_type == VBLK) { |
| 1428 | nbp->vb_buf.b_dev = vp->v_rdev; |
| 1429 | } |
| 1430 | |
| 1431 | nbp->vb_xfer = vnx; /* patch it back in to vnx */ |
| 1432 | |
| 1433 | /* |
| 1434 | * Just sort by block number |
| 1435 | */ |
| 1436 | s = splbio(); |
| 1437 | if (vnx->vx_error != 0) { |
| 1438 | buf_destroy(&nbp->vb_buf); |
| 1439 | pool_put(&vndbuf_pool, nbp); |
| 1440 | goto out; |
| 1441 | } |
| 1442 | vnx->vx_pending++; |
| 1443 | |
| 1444 | /* sort it in and start I/O if we are not over our limit */ |
| 1445 | /* XXXAD locking */ |
| 1446 | bufq_put(sdp->swd_tab, &nbp->vb_buf); |
| 1447 | sw_reg_start(sdp); |
| 1448 | splx(s); |
| 1449 | |
| 1450 | /* |
| 1451 | * advance to the next I/O |
| 1452 | */ |
| 1453 | byteoff += sz; |
| 1454 | addr += sz; |
| 1455 | } |
| 1456 | |
| 1457 | s = splbio(); |
| 1458 | |
| 1459 | out: /* Arrive here at splbio */ |
| 1460 | vnx->vx_flags &= ~VX_BUSY; |
| 1461 | if (vnx->vx_pending == 0) { |
| 1462 | error = vnx->vx_error; |
| 1463 | pool_put(&vndxfer_pool, vnx); |
| 1464 | bp->b_error = error; |
| 1465 | biodone(bp); |
| 1466 | } |
| 1467 | splx(s); |
| 1468 | } |
| 1469 | |
| 1470 | /* |
| 1471 | * sw_reg_start: start an I/O request on the requested swapdev |
| 1472 | * |
| 1473 | * => reqs are sorted by b_rawblkno (above) |
| 1474 | */ |
| 1475 | static void |
| 1476 | sw_reg_start(struct swapdev *sdp) |
| 1477 | { |
| 1478 | struct buf *bp; |
| 1479 | struct vnode *vp; |
| 1480 | UVMHIST_FUNC("sw_reg_start" ); UVMHIST_CALLED(pdhist); |
| 1481 | |
| 1482 | /* recursion control */ |
| 1483 | if ((sdp->swd_flags & SWF_BUSY) != 0) |
| 1484 | return; |
| 1485 | |
| 1486 | sdp->swd_flags |= SWF_BUSY; |
| 1487 | |
| 1488 | while (sdp->swd_active < sdp->swd_maxactive) { |
| 1489 | bp = bufq_get(sdp->swd_tab); |
| 1490 | if (bp == NULL) |
| 1491 | break; |
| 1492 | sdp->swd_active++; |
| 1493 | |
| 1494 | UVMHIST_LOG(pdhist, |
| 1495 | "sw_reg_start: bp %p vp %p blkno %p cnt %lx" , |
| 1496 | bp, bp->b_vp, bp->b_blkno, bp->b_bcount); |
| 1497 | vp = bp->b_vp; |
| 1498 | KASSERT(bp->b_objlock == vp->v_interlock); |
| 1499 | if ((bp->b_flags & B_READ) == 0) { |
| 1500 | mutex_enter(vp->v_interlock); |
| 1501 | vp->v_numoutput++; |
| 1502 | mutex_exit(vp->v_interlock); |
| 1503 | } |
| 1504 | VOP_STRATEGY(vp, bp); |
| 1505 | } |
| 1506 | sdp->swd_flags &= ~SWF_BUSY; |
| 1507 | } |
| 1508 | |
| 1509 | /* |
| 1510 | * sw_reg_biodone: one of our i/o's has completed |
| 1511 | */ |
| 1512 | static void |
| 1513 | sw_reg_biodone(struct buf *bp) |
| 1514 | { |
| 1515 | workqueue_enqueue(sw_reg_workqueue, &bp->b_work, NULL); |
| 1516 | } |
| 1517 | |
| 1518 | /* |
| 1519 | * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup |
| 1520 | * |
| 1521 | * => note that we can recover the vndbuf struct by casting the buf ptr |
| 1522 | */ |
| 1523 | static void |
| 1524 | sw_reg_iodone(struct work *wk, void *dummy) |
| 1525 | { |
| 1526 | struct vndbuf *vbp = (void *)wk; |
| 1527 | struct vndxfer *vnx = vbp->vb_xfer; |
| 1528 | struct buf *pbp = vnx->vx_bp; /* parent buffer */ |
| 1529 | struct swapdev *sdp = vnx->vx_sdp; |
| 1530 | int s, resid, error; |
| 1531 | KASSERT(&vbp->vb_buf.b_work == wk); |
| 1532 | UVMHIST_FUNC("sw_reg_iodone" ); UVMHIST_CALLED(pdhist); |
| 1533 | |
| 1534 | UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=%x addr=%p" , |
| 1535 | vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); |
| 1536 | UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx" , |
| 1537 | vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); |
| 1538 | |
| 1539 | /* |
| 1540 | * protect vbp at splbio and update. |
| 1541 | */ |
| 1542 | |
| 1543 | s = splbio(); |
| 1544 | resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; |
| 1545 | pbp->b_resid -= resid; |
| 1546 | vnx->vx_pending--; |
| 1547 | |
| 1548 | if (vbp->vb_buf.b_error != 0) { |
| 1549 | /* pass error upward */ |
| 1550 | error = vbp->vb_buf.b_error ? vbp->vb_buf.b_error : EIO; |
| 1551 | UVMHIST_LOG(pdhist, " got error=%d !" , error, 0, 0, 0); |
| 1552 | vnx->vx_error = error; |
| 1553 | } |
| 1554 | |
| 1555 | /* |
| 1556 | * kill vbp structure |
| 1557 | */ |
| 1558 | buf_destroy(&vbp->vb_buf); |
| 1559 | pool_put(&vndbuf_pool, vbp); |
| 1560 | |
| 1561 | /* |
| 1562 | * wrap up this transaction if it has run to completion or, in |
| 1563 | * case of an error, when all auxiliary buffers have returned. |
| 1564 | */ |
| 1565 | if (vnx->vx_error != 0) { |
| 1566 | /* pass error upward */ |
| 1567 | error = vnx->vx_error; |
| 1568 | if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { |
| 1569 | pbp->b_error = error; |
| 1570 | biodone(pbp); |
| 1571 | pool_put(&vndxfer_pool, vnx); |
| 1572 | } |
| 1573 | } else if (pbp->b_resid == 0) { |
| 1574 | KASSERT(vnx->vx_pending == 0); |
| 1575 | if ((vnx->vx_flags & VX_BUSY) == 0) { |
| 1576 | UVMHIST_LOG(pdhist, " iodone error=%d !" , |
| 1577 | pbp, vnx->vx_error, 0, 0); |
| 1578 | biodone(pbp); |
| 1579 | pool_put(&vndxfer_pool, vnx); |
| 1580 | } |
| 1581 | } |
| 1582 | |
| 1583 | /* |
| 1584 | * done! start next swapdev I/O if one is pending |
| 1585 | */ |
| 1586 | sdp->swd_active--; |
| 1587 | sw_reg_start(sdp); |
| 1588 | splx(s); |
| 1589 | } |
| 1590 | |
| 1591 | |
| 1592 | /* |
| 1593 | * uvm_swap_alloc: allocate space on swap |
| 1594 | * |
| 1595 | * => allocation is done "round robin" down the priority list, as we |
| 1596 | * allocate in a priority we "rotate" the circle queue. |
| 1597 | * => space can be freed with uvm_swap_free |
| 1598 | * => we return the page slot number in /dev/drum (0 == invalid slot) |
| 1599 | * => we lock uvm_swap_data_lock |
| 1600 | * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM |
| 1601 | */ |
| 1602 | int |
| 1603 | uvm_swap_alloc(int *nslots /* IN/OUT */, bool lessok) |
| 1604 | { |
| 1605 | struct swapdev *sdp; |
| 1606 | struct swappri *spp; |
| 1607 | UVMHIST_FUNC("uvm_swap_alloc" ); UVMHIST_CALLED(pdhist); |
| 1608 | |
| 1609 | /* |
| 1610 | * no swap devices configured yet? definite failure. |
| 1611 | */ |
| 1612 | if (uvmexp.nswapdev < 1) |
| 1613 | return 0; |
| 1614 | |
| 1615 | /* |
| 1616 | * XXXJAK: BEGIN HACK |
| 1617 | * |
| 1618 | * blist_alloc() in subr_blist.c will panic if we try to allocate |
| 1619 | * too many slots. |
| 1620 | */ |
| 1621 | if (*nslots > BLIST_MAX_ALLOC) { |
| 1622 | if (__predict_false(lessok == false)) |
| 1623 | return 0; |
| 1624 | *nslots = BLIST_MAX_ALLOC; |
| 1625 | } |
| 1626 | /* XXXJAK: END HACK */ |
| 1627 | |
| 1628 | /* |
| 1629 | * lock data lock, convert slots into blocks, and enter loop |
| 1630 | */ |
| 1631 | mutex_enter(&uvm_swap_data_lock); |
| 1632 | |
| 1633 | ReTry: /* XXXMRG */ |
| 1634 | LIST_FOREACH(spp, &swap_priority, spi_swappri) { |
| 1635 | TAILQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { |
| 1636 | uint64_t result; |
| 1637 | |
| 1638 | /* if it's not enabled, then we can't swap from it */ |
| 1639 | if ((sdp->swd_flags & SWF_ENABLE) == 0) |
| 1640 | continue; |
| 1641 | if (sdp->swd_npginuse + *nslots > sdp->swd_npages) |
| 1642 | continue; |
| 1643 | result = blist_alloc(sdp->swd_blist, *nslots); |
| 1644 | if (result == BLIST_NONE) { |
| 1645 | continue; |
| 1646 | } |
| 1647 | KASSERT(result < sdp->swd_drumsize); |
| 1648 | |
| 1649 | /* |
| 1650 | * successful allocation! now rotate the tailq. |
| 1651 | */ |
| 1652 | TAILQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); |
| 1653 | TAILQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); |
| 1654 | sdp->swd_npginuse += *nslots; |
| 1655 | uvmexp.swpginuse += *nslots; |
| 1656 | mutex_exit(&uvm_swap_data_lock); |
| 1657 | /* done! return drum slot number */ |
| 1658 | UVMHIST_LOG(pdhist, |
| 1659 | "success! returning %d slots starting at %d" , |
| 1660 | *nslots, result + sdp->swd_drumoffset, 0, 0); |
| 1661 | return (result + sdp->swd_drumoffset); |
| 1662 | } |
| 1663 | } |
| 1664 | |
| 1665 | /* XXXMRG: BEGIN HACK */ |
| 1666 | if (*nslots > 1 && lessok) { |
| 1667 | *nslots = 1; |
| 1668 | /* XXXMRG: ugh! blist should support this for us */ |
| 1669 | goto ReTry; |
| 1670 | } |
| 1671 | /* XXXMRG: END HACK */ |
| 1672 | |
| 1673 | mutex_exit(&uvm_swap_data_lock); |
| 1674 | return 0; |
| 1675 | } |
| 1676 | |
| 1677 | /* |
| 1678 | * uvm_swapisfull: return true if most of available swap is allocated |
| 1679 | * and in use. we don't count some small portion as it may be inaccessible |
| 1680 | * to us at any given moment, for example if there is lock contention or if |
| 1681 | * pages are busy. |
| 1682 | */ |
| 1683 | bool |
| 1684 | uvm_swapisfull(void) |
| 1685 | { |
| 1686 | int swpgonly; |
| 1687 | bool rv; |
| 1688 | |
| 1689 | mutex_enter(&uvm_swap_data_lock); |
| 1690 | KASSERT(uvmexp.swpgonly <= uvmexp.swpages); |
| 1691 | swpgonly = (int)((uint64_t)uvmexp.swpgonly * 100 / |
| 1692 | uvm_swapisfull_factor); |
| 1693 | rv = (swpgonly >= uvmexp.swpgavail); |
| 1694 | mutex_exit(&uvm_swap_data_lock); |
| 1695 | |
| 1696 | return (rv); |
| 1697 | } |
| 1698 | |
| 1699 | /* |
| 1700 | * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors |
| 1701 | * |
| 1702 | * => we lock uvm_swap_data_lock |
| 1703 | */ |
| 1704 | void |
| 1705 | uvm_swap_markbad(int startslot, int nslots) |
| 1706 | { |
| 1707 | struct swapdev *sdp; |
| 1708 | UVMHIST_FUNC("uvm_swap_markbad" ); UVMHIST_CALLED(pdhist); |
| 1709 | |
| 1710 | mutex_enter(&uvm_swap_data_lock); |
| 1711 | sdp = swapdrum_getsdp(startslot); |
| 1712 | KASSERT(sdp != NULL); |
| 1713 | |
| 1714 | /* |
| 1715 | * we just keep track of how many pages have been marked bad |
| 1716 | * in this device, to make everything add up in swap_off(). |
| 1717 | * we assume here that the range of slots will all be within |
| 1718 | * one swap device. |
| 1719 | */ |
| 1720 | |
| 1721 | KASSERT(uvmexp.swpgonly >= nslots); |
| 1722 | uvmexp.swpgonly -= nslots; |
| 1723 | sdp->swd_npgbad += nslots; |
| 1724 | UVMHIST_LOG(pdhist, "now %d bad" , sdp->swd_npgbad, 0,0,0); |
| 1725 | mutex_exit(&uvm_swap_data_lock); |
| 1726 | } |
| 1727 | |
| 1728 | /* |
| 1729 | * uvm_swap_free: free swap slots |
| 1730 | * |
| 1731 | * => this can be all or part of an allocation made by uvm_swap_alloc |
| 1732 | * => we lock uvm_swap_data_lock |
| 1733 | */ |
| 1734 | void |
| 1735 | uvm_swap_free(int startslot, int nslots) |
| 1736 | { |
| 1737 | struct swapdev *sdp; |
| 1738 | UVMHIST_FUNC("uvm_swap_free" ); UVMHIST_CALLED(pdhist); |
| 1739 | |
| 1740 | UVMHIST_LOG(pdhist, "freeing %d slots starting at %d" , nslots, |
| 1741 | startslot, 0, 0); |
| 1742 | |
| 1743 | /* |
| 1744 | * ignore attempts to free the "bad" slot. |
| 1745 | */ |
| 1746 | |
| 1747 | if (startslot == SWSLOT_BAD) { |
| 1748 | return; |
| 1749 | } |
| 1750 | |
| 1751 | /* |
| 1752 | * convert drum slot offset back to sdp, free the blocks |
| 1753 | * in the extent, and return. must hold pri lock to do |
| 1754 | * lookup and access the extent. |
| 1755 | */ |
| 1756 | |
| 1757 | mutex_enter(&uvm_swap_data_lock); |
| 1758 | sdp = swapdrum_getsdp(startslot); |
| 1759 | KASSERT(uvmexp.nswapdev >= 1); |
| 1760 | KASSERT(sdp != NULL); |
| 1761 | KASSERT(sdp->swd_npginuse >= nslots); |
| 1762 | blist_free(sdp->swd_blist, startslot - sdp->swd_drumoffset, nslots); |
| 1763 | sdp->swd_npginuse -= nslots; |
| 1764 | uvmexp.swpginuse -= nslots; |
| 1765 | mutex_exit(&uvm_swap_data_lock); |
| 1766 | } |
| 1767 | |
| 1768 | /* |
| 1769 | * uvm_swap_put: put any number of pages into a contig place on swap |
| 1770 | * |
| 1771 | * => can be sync or async |
| 1772 | */ |
| 1773 | |
| 1774 | int |
| 1775 | uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) |
| 1776 | { |
| 1777 | int error; |
| 1778 | |
| 1779 | error = uvm_swap_io(ppsp, swslot, npages, B_WRITE | |
| 1780 | ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); |
| 1781 | return error; |
| 1782 | } |
| 1783 | |
| 1784 | /* |
| 1785 | * uvm_swap_get: get a single page from swap |
| 1786 | * |
| 1787 | * => usually a sync op (from fault) |
| 1788 | */ |
| 1789 | |
| 1790 | int |
| 1791 | uvm_swap_get(struct vm_page *page, int swslot, int flags) |
| 1792 | { |
| 1793 | int error; |
| 1794 | |
| 1795 | uvmexp.nswget++; |
| 1796 | KASSERT(flags & PGO_SYNCIO); |
| 1797 | if (swslot == SWSLOT_BAD) { |
| 1798 | return EIO; |
| 1799 | } |
| 1800 | |
| 1801 | error = uvm_swap_io(&page, swslot, 1, B_READ | |
| 1802 | ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); |
| 1803 | if (error == 0) { |
| 1804 | |
| 1805 | /* |
| 1806 | * this page is no longer only in swap. |
| 1807 | */ |
| 1808 | |
| 1809 | mutex_enter(&uvm_swap_data_lock); |
| 1810 | KASSERT(uvmexp.swpgonly > 0); |
| 1811 | uvmexp.swpgonly--; |
| 1812 | mutex_exit(&uvm_swap_data_lock); |
| 1813 | } |
| 1814 | return error; |
| 1815 | } |
| 1816 | |
| 1817 | /* |
| 1818 | * uvm_swap_io: do an i/o operation to swap |
| 1819 | */ |
| 1820 | |
| 1821 | static int |
| 1822 | uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) |
| 1823 | { |
| 1824 | daddr_t startblk; |
| 1825 | struct buf *bp; |
| 1826 | vaddr_t kva; |
| 1827 | int error, mapinflags; |
| 1828 | bool write, async; |
| 1829 | UVMHIST_FUNC("uvm_swap_io" ); UVMHIST_CALLED(pdhist); |
| 1830 | |
| 1831 | UVMHIST_LOG(pdhist, "<- called, startslot=%d, npages=%d, flags=%d" , |
| 1832 | startslot, npages, flags, 0); |
| 1833 | |
| 1834 | write = (flags & B_READ) == 0; |
| 1835 | async = (flags & B_ASYNC) != 0; |
| 1836 | |
| 1837 | /* |
| 1838 | * allocate a buf for the i/o. |
| 1839 | */ |
| 1840 | |
| 1841 | KASSERT(curlwp != uvm.pagedaemon_lwp || (write && async)); |
| 1842 | bp = getiobuf(swapdev_vp, curlwp != uvm.pagedaemon_lwp); |
| 1843 | if (bp == NULL) { |
| 1844 | uvm_aio_aiodone_pages(pps, npages, true, ENOMEM); |
| 1845 | return ENOMEM; |
| 1846 | } |
| 1847 | |
| 1848 | /* |
| 1849 | * convert starting drum slot to block number |
| 1850 | */ |
| 1851 | |
| 1852 | startblk = btodb((uint64_t)startslot << PAGE_SHIFT); |
| 1853 | |
| 1854 | /* |
| 1855 | * first, map the pages into the kernel. |
| 1856 | */ |
| 1857 | |
| 1858 | mapinflags = !write ? |
| 1859 | UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_READ : |
| 1860 | UVMPAGER_MAPIN_WAITOK|UVMPAGER_MAPIN_WRITE; |
| 1861 | kva = uvm_pagermapin(pps, npages, mapinflags); |
| 1862 | |
| 1863 | /* |
| 1864 | * fill in the bp/sbp. we currently route our i/o through |
| 1865 | * /dev/drum's vnode [swapdev_vp]. |
| 1866 | */ |
| 1867 | |
| 1868 | bp->b_cflags = BC_BUSY | BC_NOCACHE; |
| 1869 | bp->b_flags = (flags & (B_READ|B_ASYNC)); |
| 1870 | bp->b_proc = &proc0; /* XXX */ |
| 1871 | bp->b_vnbufs.le_next = NOLIST; |
| 1872 | bp->b_data = (void *)kva; |
| 1873 | bp->b_blkno = startblk; |
| 1874 | bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; |
| 1875 | |
| 1876 | /* |
| 1877 | * bump v_numoutput (counter of number of active outputs). |
| 1878 | */ |
| 1879 | |
| 1880 | if (write) { |
| 1881 | mutex_enter(swapdev_vp->v_interlock); |
| 1882 | swapdev_vp->v_numoutput++; |
| 1883 | mutex_exit(swapdev_vp->v_interlock); |
| 1884 | } |
| 1885 | |
| 1886 | /* |
| 1887 | * for async ops we must set up the iodone handler. |
| 1888 | */ |
| 1889 | |
| 1890 | if (async) { |
| 1891 | bp->b_iodone = uvm_aio_biodone; |
| 1892 | UVMHIST_LOG(pdhist, "doing async!" , 0, 0, 0, 0); |
| 1893 | if (curlwp == uvm.pagedaemon_lwp) |
| 1894 | BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); |
| 1895 | else |
| 1896 | BIO_SETPRIO(bp, BPRIO_TIMELIMITED); |
| 1897 | } else { |
| 1898 | bp->b_iodone = NULL; |
| 1899 | BIO_SETPRIO(bp, BPRIO_TIMECRITICAL); |
| 1900 | } |
| 1901 | UVMHIST_LOG(pdhist, |
| 1902 | "about to start io: data = %p blkno = 0x%x, bcount = %ld" , |
| 1903 | bp->b_data, bp->b_blkno, bp->b_bcount, 0); |
| 1904 | |
| 1905 | /* |
| 1906 | * now we start the I/O, and if async, return. |
| 1907 | */ |
| 1908 | |
| 1909 | VOP_STRATEGY(swapdev_vp, bp); |
| 1910 | if (async) |
| 1911 | return 0; |
| 1912 | |
| 1913 | /* |
| 1914 | * must be sync i/o. wait for it to finish |
| 1915 | */ |
| 1916 | |
| 1917 | error = biowait(bp); |
| 1918 | |
| 1919 | /* |
| 1920 | * kill the pager mapping |
| 1921 | */ |
| 1922 | |
| 1923 | uvm_pagermapout(kva, npages); |
| 1924 | |
| 1925 | /* |
| 1926 | * now dispose of the buf and we're done. |
| 1927 | */ |
| 1928 | |
| 1929 | if (write) { |
| 1930 | mutex_enter(swapdev_vp->v_interlock); |
| 1931 | vwakeup(bp); |
| 1932 | mutex_exit(swapdev_vp->v_interlock); |
| 1933 | } |
| 1934 | putiobuf(bp); |
| 1935 | UVMHIST_LOG(pdhist, "<- done (sync) error=%d" , error, 0, 0, 0); |
| 1936 | |
| 1937 | return (error); |
| 1938 | } |
| 1939 | |