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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pageout.c
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1 /*- 2 * Copyright (c) 1991 Regents of the University of California. 3 * All rights reserved. 4 * Copyright (c) 1994 John S. Dyson 5 * All rights reserved. 6 * Copyright (c) 1994 David Greenman 7 * All rights reserved. 8 * Copyright (c) 2005 Yahoo! Technologies Norway AS 9 * All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * The Mach Operating System project at Carnegie-Mellon University. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * from: @(#)vm_pageout.c 7.4 (Berkeley) 5/7/91 43 * 44 * 45 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 46 * All rights reserved. 47 * 48 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 49 * 50 * Permission to use, copy, modify and distribute this software and 51 * its documentation is hereby granted, provided that both the copyright 52 * notice and this permission notice appear in all copies of the 53 * software, derivative works or modified versions, and any portions 54 * thereof, and that both notices appear in supporting documentation. 55 * 56 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 57 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 58 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 59 * 60 * Carnegie Mellon requests users of this software to return to 61 * 62 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 63 * School of Computer Science 64 * Carnegie Mellon University 65 * Pittsburgh PA 15213-3890 66 * 67 * any improvements or extensions that they make and grant Carnegie the 68 * rights to redistribute these changes. 69 */ 70 71 /* 72 * The proverbial page-out daemon. 73 */ 74 75 #include <sys/cdefs.h> 76 __FBSDID("$FreeBSD$"); 77 78 #include "opt_vm.h" 79 #include "opt_kdtrace.h" 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/kernel.h> 83 #include <sys/eventhandler.h> 84 #include <sys/lock.h> 85 #include <sys/mutex.h> 86 #include <sys/proc.h> 87 #include <sys/kthread.h> 88 #include <sys/ktr.h> 89 #include <sys/mount.h> 90 #include <sys/racct.h> 91 #include <sys/resourcevar.h> 92 #include <sys/sched.h> 93 #include <sys/sdt.h> 94 #include <sys/signalvar.h> 95 #include <sys/smp.h> 96 #include <sys/time.h> 97 #include <sys/vnode.h> 98 #include <sys/vmmeter.h> 99 #include <sys/rwlock.h> 100 #include <sys/sx.h> 101 #include <sys/sysctl.h> 102 103 #include <vm/vm.h> 104 #include <vm/vm_param.h> 105 #include <vm/vm_object.h> 106 #include <vm/vm_page.h> 107 #include <vm/vm_map.h> 108 #include <vm/vm_pageout.h> 109 #include <vm/vm_pager.h> 110 #include <vm/vm_phys.h> 111 #include <vm/swap_pager.h> 112 #include <vm/vm_extern.h> 113 #include <vm/uma.h> 114 115 /* 116 * System initialization 117 */ 118 119 /* the kernel process "vm_pageout"*/ 120 static void vm_pageout(void); 121 static void vm_pageout_init(void); 122 static int vm_pageout_clean(vm_page_t); 123 static void vm_pageout_scan(struct vm_domain *vmd, int pass); 124 static void vm_pageout_mightbe_oom(struct vm_domain *vmd, int page_shortage, 125 int starting_page_shortage); 126 127 SYSINIT(pagedaemon_init, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, vm_pageout_init, 128 NULL); 129 130 struct proc *pageproc; 131 132 static struct kproc_desc page_kp = { 133 "pagedaemon", 134 vm_pageout, 135 &pageproc 136 }; 137 SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_SECOND, kproc_start, 138 &page_kp); 139 140 SDT_PROVIDER_DEFINE(vm); 141 SDT_PROBE_DEFINE(vm, , , vm__lowmem_cache); 142 SDT_PROBE_DEFINE(vm, , , vm__lowmem_scan); 143 144 #if !defined(NO_SWAPPING) 145 /* the kernel process "vm_daemon"*/ 146 static void vm_daemon(void); 147 static struct proc *vmproc; 148 149 static struct kproc_desc vm_kp = { 150 "vmdaemon", 151 vm_daemon, 152 &vmproc 153 }; 154 SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp); 155 #endif 156 157 158 int vm_pages_needed; /* Event on which pageout daemon sleeps */ 159 int vm_pageout_deficit; /* Estimated number of pages deficit */ 160 int vm_pageout_pages_needed; /* flag saying that the pageout daemon needs pages */ 161 int vm_pageout_wakeup_thresh; 162 static int vm_pageout_oom_seq = 12; 163 164 #if !defined(NO_SWAPPING) 165 static int vm_pageout_req_swapout; /* XXX */ 166 static int vm_daemon_needed; 167 static struct mtx vm_daemon_mtx; 168 /* Allow for use by vm_pageout before vm_daemon is initialized. */ 169 MTX_SYSINIT(vm_daemon, &vm_daemon_mtx, "vm daemon", MTX_DEF); 170 #endif 171 static int vm_max_launder = 32; 172 static int vm_pageout_update_period; 173 static int defer_swap_pageouts; 174 static int disable_swap_pageouts; 175 static int lowmem_period = 10; 176 static time_t lowmem_uptime; 177 178 #if defined(NO_SWAPPING) 179 static int vm_swap_enabled = 0; 180 static int vm_swap_idle_enabled = 0; 181 #else 182 static int vm_swap_enabled = 1; 183 static int vm_swap_idle_enabled = 0; 184 #endif 185 186 SYSCTL_INT(_vm, OID_AUTO, pageout_wakeup_thresh, 187 CTLFLAG_RW, &vm_pageout_wakeup_thresh, 0, 188 "free page threshold for waking up the pageout daemon"); 189 190 SYSCTL_INT(_vm, OID_AUTO, max_launder, 191 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout"); 192 193 SYSCTL_INT(_vm, OID_AUTO, pageout_update_period, 194 CTLFLAG_RW, &vm_pageout_update_period, 0, 195 "Maximum active LRU update period"); 196 197 SYSCTL_INT(_vm, OID_AUTO, lowmem_period, CTLFLAG_RW, &lowmem_period, 0, 198 "Low memory callback period"); 199 200 #if defined(NO_SWAPPING) 201 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 202 CTLFLAG_RD, &vm_swap_enabled, 0, "Enable entire process swapout"); 203 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 204 CTLFLAG_RD, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 205 #else 206 SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 207 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout"); 208 SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 209 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 210 #endif 211 212 SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts, 213 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem"); 214 215 SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts, 216 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages"); 217 218 static int pageout_lock_miss; 219 SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss, 220 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout"); 221 222 SYSCTL_INT(_vm, OID_AUTO, pageout_oom_seq, 223 CTLFLAG_RW, &vm_pageout_oom_seq, 0, 224 "back-to-back calls to oom detector to start OOM"); 225 226 #define VM_PAGEOUT_PAGE_COUNT 16 227 int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 228 229 int vm_page_max_wired; /* XXX max # of wired pages system-wide */ 230 SYSCTL_INT(_vm, OID_AUTO, max_wired, 231 CTLFLAG_RW, &vm_page_max_wired, 0, "System-wide limit to wired page count"); 232 233 static boolean_t vm_pageout_fallback_object_lock(vm_page_t, vm_page_t *); 234 static boolean_t vm_pageout_launder(struct vm_pagequeue *pq, int, vm_paddr_t, 235 vm_paddr_t); 236 #if !defined(NO_SWAPPING) 237 static void vm_pageout_map_deactivate_pages(vm_map_t, long); 238 static void vm_pageout_object_deactivate_pages(pmap_t, vm_object_t, long); 239 static void vm_req_vmdaemon(int req); 240 #endif 241 static boolean_t vm_pageout_page_lock(vm_page_t, vm_page_t *); 242 243 /* 244 * Initialize a dummy page for marking the caller's place in the specified 245 * paging queue. In principle, this function only needs to set the flag 246 * PG_MARKER. Nonetheless, it write busies and initializes the hold count 247 * to one as safety precautions. 248 */ 249 static void 250 vm_pageout_init_marker(vm_page_t marker, u_short queue) 251 { 252 253 bzero(marker, sizeof(*marker)); 254 marker->flags = PG_MARKER; 255 marker->busy_lock = VPB_SINGLE_EXCLUSIVER; 256 marker->queue = queue; 257 marker->hold_count = 1; 258 } 259 260 /* 261 * vm_pageout_fallback_object_lock: 262 * 263 * Lock vm object currently associated with `m'. VM_OBJECT_TRYWLOCK is 264 * known to have failed and page queue must be either PQ_ACTIVE or 265 * PQ_INACTIVE. To avoid lock order violation, unlock the page queue 266 * while locking the vm object. Use marker page to detect page queue 267 * changes and maintain notion of next page on page queue. Return 268 * TRUE if no changes were detected, FALSE otherwise. vm object is 269 * locked on return. 270 * 271 * This function depends on both the lock portion of struct vm_object 272 * and normal struct vm_page being type stable. 273 */ 274 static boolean_t 275 vm_pageout_fallback_object_lock(vm_page_t m, vm_page_t *next) 276 { 277 struct vm_page marker; 278 struct vm_pagequeue *pq; 279 boolean_t unchanged; 280 u_short queue; 281 vm_object_t object; 282 283 queue = m->queue; 284 vm_pageout_init_marker(&marker, queue); 285 pq = vm_page_pagequeue(m); 286 object = m->object; 287 288 TAILQ_INSERT_AFTER(&pq->pq_pl, m, &marker, plinks.q); 289 vm_pagequeue_unlock(pq); 290 vm_page_unlock(m); 291 VM_OBJECT_WLOCK(object); 292 vm_page_lock(m); 293 vm_pagequeue_lock(pq); 294 295 /* 296 * The page's object might have changed, and/or the page might 297 * have moved from its original position in the queue. If the 298 * page's object has changed, then the caller should abandon 299 * processing the page because the wrong object lock was 300 * acquired. Use the marker's plinks.q, not the page's, to 301 * determine if the page has been moved. The state of the 302 * page's plinks.q can be indeterminate; whereas, the marker's 303 * plinks.q must be valid. 304 */ 305 *next = TAILQ_NEXT(&marker, plinks.q); 306 unchanged = m->object == object && 307 m == TAILQ_PREV(&marker, pglist, plinks.q); 308 KASSERT(!unchanged || m->queue == queue, 309 ("page %p queue %d %d", m, queue, m->queue)); 310 TAILQ_REMOVE(&pq->pq_pl, &marker, plinks.q); 311 return (unchanged); 312 } 313 314 /* 315 * Lock the page while holding the page queue lock. Use marker page 316 * to detect page queue changes and maintain notion of next page on 317 * page queue. Return TRUE if no changes were detected, FALSE 318 * otherwise. The page is locked on return. The page queue lock might 319 * be dropped and reacquired. 320 * 321 * This function depends on normal struct vm_page being type stable. 322 */ 323 static boolean_t 324 vm_pageout_page_lock(vm_page_t m, vm_page_t *next) 325 { 326 struct vm_page marker; 327 struct vm_pagequeue *pq; 328 boolean_t unchanged; 329 u_short queue; 330 331 vm_page_lock_assert(m, MA_NOTOWNED); 332 if (vm_page_trylock(m)) 333 return (TRUE); 334 335 queue = m->queue; 336 vm_pageout_init_marker(&marker, queue); 337 pq = vm_page_pagequeue(m); 338 339 TAILQ_INSERT_AFTER(&pq->pq_pl, m, &marker, plinks.q); 340 vm_pagequeue_unlock(pq); 341 vm_page_lock(m); 342 vm_pagequeue_lock(pq); 343 344 /* Page queue might have changed. */ 345 *next = TAILQ_NEXT(&marker, plinks.q); 346 unchanged = m == TAILQ_PREV(&marker, pglist, plinks.q); 347 KASSERT(!unchanged || m->queue == queue, 348 ("page %p queue %d %d", m, queue, m->queue)); 349 TAILQ_REMOVE(&pq->pq_pl, &marker, plinks.q); 350 return (unchanged); 351 } 352 353 /* 354 * vm_pageout_clean: 355 * 356 * Clean the page and remove it from the laundry. 357 * 358 * We set the busy bit to cause potential page faults on this page to 359 * block. Note the careful timing, however, the busy bit isn't set till 360 * late and we cannot do anything that will mess with the page. 361 */ 362 static int 363 vm_pageout_clean(vm_page_t m) 364 { 365 vm_object_t object; 366 vm_page_t mc[2*vm_pageout_page_count], pb, ps; 367 int pageout_count; 368 int ib, is, page_base; 369 vm_pindex_t pindex = m->pindex; 370 371 vm_page_lock_assert(m, MA_OWNED); 372 object = m->object; 373 VM_OBJECT_ASSERT_WLOCKED(object); 374 375 /* 376 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP 377 * with the new swapper, but we could have serious problems paging 378 * out other object types if there is insufficient memory. 379 * 380 * Unfortunately, checking free memory here is far too late, so the 381 * check has been moved up a procedural level. 382 */ 383 384 /* 385 * Can't clean the page if it's busy or held. 386 */ 387 vm_page_assert_unbusied(m); 388 KASSERT(m->hold_count == 0, ("vm_pageout_clean: page %p is held", m)); 389 vm_page_unlock(m); 390 391 mc[vm_pageout_page_count] = pb = ps = m; 392 pageout_count = 1; 393 page_base = vm_pageout_page_count; 394 ib = 1; 395 is = 1; 396 397 /* 398 * Scan object for clusterable pages. 399 * 400 * We can cluster ONLY if: ->> the page is NOT 401 * clean, wired, busy, held, or mapped into a 402 * buffer, and one of the following: 403 * 1) The page is inactive, or a seldom used 404 * active page. 405 * -or- 406 * 2) we force the issue. 407 * 408 * During heavy mmap/modification loads the pageout 409 * daemon can really fragment the underlying file 410 * due to flushing pages out of order and not trying 411 * align the clusters (which leave sporatic out-of-order 412 * holes). To solve this problem we do the reverse scan 413 * first and attempt to align our cluster, then do a 414 * forward scan if room remains. 415 */ 416 more: 417 while (ib && pageout_count < vm_pageout_page_count) { 418 vm_page_t p; 419 420 if (ib > pindex) { 421 ib = 0; 422 break; 423 } 424 425 if ((p = vm_page_prev(pb)) == NULL || vm_page_busied(p)) { 426 ib = 0; 427 break; 428 } 429 vm_page_test_dirty(p); 430 if (p->dirty == 0) { 431 ib = 0; 432 break; 433 } 434 vm_page_lock(p); 435 if (p->queue != PQ_INACTIVE || 436 p->hold_count != 0) { /* may be undergoing I/O */ 437 vm_page_unlock(p); 438 ib = 0; 439 break; 440 } 441 vm_page_unlock(p); 442 mc[--page_base] = pb = p; 443 ++pageout_count; 444 ++ib; 445 /* 446 * alignment boundry, stop here and switch directions. Do 447 * not clear ib. 448 */ 449 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0) 450 break; 451 } 452 453 while (pageout_count < vm_pageout_page_count && 454 pindex + is < object->size) { 455 vm_page_t p; 456 457 if ((p = vm_page_next(ps)) == NULL || vm_page_busied(p)) 458 break; 459 vm_page_test_dirty(p); 460 if (p->dirty == 0) 461 break; 462 vm_page_lock(p); 463 if (p->queue != PQ_INACTIVE || 464 p->hold_count != 0) { /* may be undergoing I/O */ 465 vm_page_unlock(p); 466 break; 467 } 468 vm_page_unlock(p); 469 mc[page_base + pageout_count] = ps = p; 470 ++pageout_count; 471 ++is; 472 } 473 474 /* 475 * If we exhausted our forward scan, continue with the reverse scan 476 * when possible, even past a page boundry. This catches boundry 477 * conditions. 478 */ 479 if (ib && pageout_count < vm_pageout_page_count) 480 goto more; 481 482 /* 483 * we allow reads during pageouts... 484 */ 485 return (vm_pageout_flush(&mc[page_base], pageout_count, 0, 0, NULL, 486 NULL)); 487 } 488 489 /* 490 * vm_pageout_flush() - launder the given pages 491 * 492 * The given pages are laundered. Note that we setup for the start of 493 * I/O ( i.e. busy the page ), mark it read-only, and bump the object 494 * reference count all in here rather then in the parent. If we want 495 * the parent to do more sophisticated things we may have to change 496 * the ordering. 497 * 498 * Returned runlen is the count of pages between mreq and first 499 * page after mreq with status VM_PAGER_AGAIN. 500 * *eio is set to TRUE if pager returned VM_PAGER_ERROR or VM_PAGER_FAIL 501 * for any page in runlen set. 502 */ 503 int 504 vm_pageout_flush(vm_page_t *mc, int count, int flags, int mreq, int *prunlen, 505 boolean_t *eio) 506 { 507 vm_object_t object = mc[0]->object; 508 int pageout_status[count]; 509 int numpagedout = 0; 510 int i, runlen; 511 512 VM_OBJECT_ASSERT_WLOCKED(object); 513 514 /* 515 * Initiate I/O. Bump the vm_page_t->busy counter and 516 * mark the pages read-only. 517 * 518 * We do not have to fixup the clean/dirty bits here... we can 519 * allow the pager to do it after the I/O completes. 520 * 521 * NOTE! mc[i]->dirty may be partial or fragmented due to an 522 * edge case with file fragments. 523 */ 524 for (i = 0; i < count; i++) { 525 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, 526 ("vm_pageout_flush: partially invalid page %p index %d/%d", 527 mc[i], i, count)); 528 vm_page_sbusy(mc[i]); 529 pmap_remove_write(mc[i]); 530 } 531 vm_object_pip_add(object, count); 532 533 vm_pager_put_pages(object, mc, count, flags, pageout_status); 534 535 runlen = count - mreq; 536 if (eio != NULL) 537 *eio = FALSE; 538 for (i = 0; i < count; i++) { 539 vm_page_t mt = mc[i]; 540 541 KASSERT(pageout_status[i] == VM_PAGER_PEND || 542 !pmap_page_is_write_mapped(mt), 543 ("vm_pageout_flush: page %p is not write protected", mt)); 544 switch (pageout_status[i]) { 545 case VM_PAGER_OK: 546 case VM_PAGER_PEND: 547 numpagedout++; 548 break; 549 case VM_PAGER_BAD: 550 /* 551 * Page outside of range of object. Right now we 552 * essentially lose the changes by pretending it 553 * worked. 554 */ 555 vm_page_undirty(mt); 556 break; 557 case VM_PAGER_ERROR: 558 case VM_PAGER_FAIL: 559 /* 560 * If page couldn't be paged out, then reactivate the 561 * page so it doesn't clog the inactive list. (We 562 * will try paging out it again later). 563 */ 564 vm_page_lock(mt); 565 vm_page_activate(mt); 566 vm_page_unlock(mt); 567 if (eio != NULL && i >= mreq && i - mreq < runlen) 568 *eio = TRUE; 569 break; 570 case VM_PAGER_AGAIN: 571 if (i >= mreq && i - mreq < runlen) 572 runlen = i - mreq; 573 break; 574 } 575 576 /* 577 * If the operation is still going, leave the page busy to 578 * block all other accesses. Also, leave the paging in 579 * progress indicator set so that we don't attempt an object 580 * collapse. 581 */ 582 if (pageout_status[i] != VM_PAGER_PEND) { 583 vm_object_pip_wakeup(object); 584 vm_page_sunbusy(mt); 585 if (vm_page_count_severe()) { 586 vm_page_lock(mt); 587 vm_page_try_to_cache(mt); 588 vm_page_unlock(mt); 589 } 590 } 591 } 592 if (prunlen != NULL) 593 *prunlen = runlen; 594 return (numpagedout); 595 } 596 597 static boolean_t 598 vm_pageout_launder(struct vm_pagequeue *pq, int tries, vm_paddr_t low, 599 vm_paddr_t high) 600 { 601 struct mount *mp; 602 struct vnode *vp; 603 vm_object_t object; 604 vm_paddr_t pa; 605 vm_page_t m, m_tmp, next; 606 int lockmode; 607 608 vm_pagequeue_lock(pq); 609 TAILQ_FOREACH_SAFE(m, &pq->pq_pl, plinks.q, next) { 610 if ((m->flags & PG_MARKER) != 0) 611 continue; 612 pa = VM_PAGE_TO_PHYS(m); 613 if (pa < low || pa + PAGE_SIZE > high) 614 continue; 615 if (!vm_pageout_page_lock(m, &next) || m->hold_count != 0) { 616 vm_page_unlock(m); 617 continue; 618 } 619 object = m->object; 620 if ((!VM_OBJECT_TRYWLOCK(object) && 621 (!vm_pageout_fallback_object_lock(m, &next) || 622 m->hold_count != 0)) || vm_page_busied(m)) { 623 vm_page_unlock(m); 624 VM_OBJECT_WUNLOCK(object); 625 continue; 626 } 627 vm_page_test_dirty(m); 628 if (m->dirty == 0 && object->ref_count != 0) 629 pmap_remove_all(m); 630 if (m->dirty != 0) { 631 vm_page_unlock(m); 632 if (tries == 0 || (object->flags & OBJ_DEAD) != 0) { 633 VM_OBJECT_WUNLOCK(object); 634 continue; 635 } 636 if (object->type == OBJT_VNODE) { 637 vm_pagequeue_unlock(pq); 638 vp = object->handle; 639 vm_object_reference_locked(object); 640 VM_OBJECT_WUNLOCK(object); 641 (void)vn_start_write(vp, &mp, V_WAIT); 642 lockmode = MNT_SHARED_WRITES(vp->v_mount) ? 643 LK_SHARED : LK_EXCLUSIVE; 644 vn_lock(vp, lockmode | LK_RETRY); 645 VM_OBJECT_WLOCK(object); 646 vm_object_page_clean(object, 0, 0, OBJPC_SYNC); 647 VM_OBJECT_WUNLOCK(object); 648 VOP_UNLOCK(vp, 0); 649 vm_object_deallocate(object); 650 vn_finished_write(mp); 651 return (TRUE); 652 } else if (object->type == OBJT_SWAP || 653 object->type == OBJT_DEFAULT) { 654 vm_pagequeue_unlock(pq); 655 m_tmp = m; 656 vm_pageout_flush(&m_tmp, 1, VM_PAGER_PUT_SYNC, 657 0, NULL, NULL); 658 VM_OBJECT_WUNLOCK(object); 659 return (TRUE); 660 } 661 } else { 662 /* 663 * Dequeue here to prevent lock recursion in 664 * vm_page_cache(). 665 */ 666 vm_page_dequeue_locked(m); 667 vm_page_cache(m); 668 vm_page_unlock(m); 669 } 670 VM_OBJECT_WUNLOCK(object); 671 } 672 vm_pagequeue_unlock(pq); 673 return (FALSE); 674 } 675 676 /* 677 * Increase the number of cached pages. The specified value, "tries", 678 * determines which categories of pages are cached: 679 * 680 * 0: All clean, inactive pages within the specified physical address range 681 * are cached. Will not sleep. 682 * 1: The vm_lowmem handlers are called. All inactive pages within 683 * the specified physical address range are cached. May sleep. 684 * 2: The vm_lowmem handlers are called. All inactive and active pages 685 * within the specified physical address range are cached. May sleep. 686 */ 687 void 688 vm_pageout_grow_cache(int tries, vm_paddr_t low, vm_paddr_t high) 689 { 690 int actl, actmax, inactl, inactmax, dom, initial_dom; 691 static int start_dom = 0; 692 693 if (tries > 0) { 694 /* 695 * Decrease registered cache sizes. The vm_lowmem handlers 696 * may acquire locks and/or sleep, so they can only be invoked 697 * when "tries" is greater than zero. 698 */ 699 SDT_PROBE0(vm, , , vm__lowmem_cache); 700 EVENTHANDLER_INVOKE(vm_lowmem, 0); 701 702 /* 703 * We do this explicitly after the caches have been drained 704 * above. 705 */ 706 uma_reclaim(); 707 } 708 709 /* 710 * Make the next scan start on the next domain. 711 */ 712 initial_dom = atomic_fetchadd_int(&start_dom, 1) % vm_ndomains; 713 714 inactl = 0; 715 inactmax = cnt.v_inactive_count; 716 actl = 0; 717 actmax = tries < 2 ? 0 : cnt.v_active_count; 718 dom = initial_dom; 719 720 /* 721 * Scan domains in round-robin order, first inactive queues, 722 * then active. Since domain usually owns large physically 723 * contiguous chunk of memory, it makes sense to completely 724 * exhaust one domain before switching to next, while growing 725 * the pool of contiguous physical pages. 726 * 727 * Do not even start launder a domain which cannot contain 728 * the specified address range, as indicated by segments 729 * constituting the domain. 730 */ 731 again_inact: 732 if (inactl < inactmax) { 733 if (vm_phys_domain_intersects(vm_dom[dom].vmd_segs, 734 low, high) && 735 vm_pageout_launder(&vm_dom[dom].vmd_pagequeues[PQ_INACTIVE], 736 tries, low, high)) { 737 inactl++; 738 goto again_inact; 739 } 740 if (++dom == vm_ndomains) 741 dom = 0; 742 if (dom != initial_dom) 743 goto again_inact; 744 } 745 again_act: 746 if (actl < actmax) { 747 if (vm_phys_domain_intersects(vm_dom[dom].vmd_segs, 748 low, high) && 749 vm_pageout_launder(&vm_dom[dom].vmd_pagequeues[PQ_ACTIVE], 750 tries, low, high)) { 751 actl++; 752 goto again_act; 753 } 754 if (++dom == vm_ndomains) 755 dom = 0; 756 if (dom != initial_dom) 757 goto again_act; 758 } 759 } 760 761 #if !defined(NO_SWAPPING) 762 /* 763 * vm_pageout_object_deactivate_pages 764 * 765 * Deactivate enough pages to satisfy the inactive target 766 * requirements. 767 * 768 * The object and map must be locked. 769 */ 770 static void 771 vm_pageout_object_deactivate_pages(pmap_t pmap, vm_object_t first_object, 772 long desired) 773 { 774 vm_object_t backing_object, object; 775 vm_page_t p; 776 int act_delta, remove_mode; 777 778 VM_OBJECT_ASSERT_LOCKED(first_object); 779 if ((first_object->flags & OBJ_FICTITIOUS) != 0) 780 return; 781 for (object = first_object;; object = backing_object) { 782 if (pmap_resident_count(pmap) <= desired) 783 goto unlock_return; 784 VM_OBJECT_ASSERT_LOCKED(object); 785 if ((object->flags & OBJ_UNMANAGED) != 0 || 786 object->paging_in_progress != 0) 787 goto unlock_return; 788 789 remove_mode = 0; 790 if (object->shadow_count > 1) 791 remove_mode = 1; 792 /* 793 * Scan the object's entire memory queue. 794 */ 795 TAILQ_FOREACH(p, &object->memq, listq) { 796 if (pmap_resident_count(pmap) <= desired) 797 goto unlock_return; 798 if (vm_page_busied(p)) 799 continue; 800 PCPU_INC(cnt.v_pdpages); 801 vm_page_lock(p); 802 if (p->wire_count != 0 || p->hold_count != 0 || 803 !pmap_page_exists_quick(pmap, p)) { 804 vm_page_unlock(p); 805 continue; 806 } 807 act_delta = pmap_ts_referenced(p); 808 if ((p->aflags & PGA_REFERENCED) != 0) { 809 if (act_delta == 0) 810 act_delta = 1; 811 vm_page_aflag_clear(p, PGA_REFERENCED); 812 } 813 if (p->queue != PQ_ACTIVE && act_delta != 0) { 814 vm_page_activate(p); 815 p->act_count += act_delta; 816 } else if (p->queue == PQ_ACTIVE) { 817 if (act_delta == 0) { 818 p->act_count -= min(p->act_count, 819 ACT_DECLINE); 820 if (!remove_mode && p->act_count == 0) { 821 pmap_remove_all(p); 822 vm_page_deactivate(p); 823 } else 824 vm_page_requeue(p); 825 } else { 826 vm_page_activate(p); 827 if (p->act_count < ACT_MAX - 828 ACT_ADVANCE) 829 p->act_count += ACT_ADVANCE; 830 vm_page_requeue(p); 831 } 832 } else if (p->queue == PQ_INACTIVE) 833 pmap_remove_all(p); 834 vm_page_unlock(p); 835 } 836 if ((backing_object = object->backing_object) == NULL) 837 goto unlock_return; 838 VM_OBJECT_RLOCK(backing_object); 839 if (object != first_object) 840 VM_OBJECT_RUNLOCK(object); 841 } 842 unlock_return: 843 if (object != first_object) 844 VM_OBJECT_RUNLOCK(object); 845 } 846 847 /* 848 * deactivate some number of pages in a map, try to do it fairly, but 849 * that is really hard to do. 850 */ 851 static void 852 vm_pageout_map_deactivate_pages(map, desired) 853 vm_map_t map; 854 long desired; 855 { 856 vm_map_entry_t tmpe; 857 vm_object_t obj, bigobj; 858 int nothingwired; 859 860 if (!vm_map_trylock(map)) 861 return; 862 863 bigobj = NULL; 864 nothingwired = TRUE; 865 866 /* 867 * first, search out the biggest object, and try to free pages from 868 * that. 869 */ 870 tmpe = map->header.next; 871 while (tmpe != &map->header) { 872 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 873 obj = tmpe->object.vm_object; 874 if (obj != NULL && VM_OBJECT_TRYRLOCK(obj)) { 875 if (obj->shadow_count <= 1 && 876 (bigobj == NULL || 877 bigobj->resident_page_count < obj->resident_page_count)) { 878 if (bigobj != NULL) 879 VM_OBJECT_RUNLOCK(bigobj); 880 bigobj = obj; 881 } else 882 VM_OBJECT_RUNLOCK(obj); 883 } 884 } 885 if (tmpe->wired_count > 0) 886 nothingwired = FALSE; 887 tmpe = tmpe->next; 888 } 889 890 if (bigobj != NULL) { 891 vm_pageout_object_deactivate_pages(map->pmap, bigobj, desired); 892 VM_OBJECT_RUNLOCK(bigobj); 893 } 894 /* 895 * Next, hunt around for other pages to deactivate. We actually 896 * do this search sort of wrong -- .text first is not the best idea. 897 */ 898 tmpe = map->header.next; 899 while (tmpe != &map->header) { 900 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 901 break; 902 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 903 obj = tmpe->object.vm_object; 904 if (obj != NULL) { 905 VM_OBJECT_RLOCK(obj); 906 vm_pageout_object_deactivate_pages(map->pmap, obj, desired); 907 VM_OBJECT_RUNLOCK(obj); 908 } 909 } 910 tmpe = tmpe->next; 911 } 912 913 #ifdef __ia64__ 914 /* 915 * Remove all non-wired, managed mappings if a process is swapped out. 916 * This will free page table pages. 917 */ 918 if (desired == 0) 919 pmap_remove_pages(map->pmap); 920 #else 921 /* 922 * Remove all mappings if a process is swapped out, this will free page 923 * table pages. 924 */ 925 if (desired == 0 && nothingwired) { 926 pmap_remove(vm_map_pmap(map), vm_map_min(map), 927 vm_map_max(map)); 928 } 929 #endif 930 931 vm_map_unlock(map); 932 } 933 #endif /* !defined(NO_SWAPPING) */ 934 935 /* 936 * vm_pageout_scan does the dirty work for the pageout daemon. 937 * 938 * pass 0 - Update active LRU/deactivate pages 939 * pass 1 - Move inactive to cache or free 940 * pass 2 - Launder dirty pages 941 */ 942 static void 943 vm_pageout_scan(struct vm_domain *vmd, int pass) 944 { 945 vm_page_t m, next; 946 struct vm_pagequeue *pq; 947 vm_object_t object; 948 long min_scan; 949 int act_delta, addl_page_shortage, deficit, maxscan, page_shortage; 950 int vnodes_skipped = 0; 951 int maxlaunder, scan_tick, scanned, starting_page_shortage; 952 int lockmode; 953 boolean_t queue_locked; 954 955 /* 956 * If we need to reclaim memory ask kernel caches to return 957 * some. We rate limit to avoid thrashing. 958 */ 959 if (vmd == &vm_dom[0] && pass > 0 && 960 (time_uptime - lowmem_uptime) >= lowmem_period) { 961 /* 962 * Decrease registered cache sizes. 963 */ 964 SDT_PROBE0(vm, , , vm__lowmem_scan); 965 EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_PAGES); 966 /* 967 * We do this explicitly after the caches have been 968 * drained above. 969 */ 970 uma_reclaim(); 971 lowmem_uptime = time_uptime; 972 } 973 974 /* 975 * The addl_page_shortage is the number of temporarily 976 * stuck pages in the inactive queue. In other words, the 977 * number of pages from the inactive count that should be 978 * discounted in setting the target for the active queue scan. 979 */ 980 addl_page_shortage = 0; 981 982 /* 983 * Calculate the number of pages we want to either free or move 984 * to the cache. 985 */ 986 if (pass > 0) { 987 deficit = atomic_readandclear_int(&vm_pageout_deficit); 988 page_shortage = vm_paging_target() + deficit; 989 } else 990 page_shortage = deficit = 0; 991 starting_page_shortage = page_shortage; 992 993 /* 994 * maxlaunder limits the number of dirty pages we flush per scan. 995 * For most systems a smaller value (16 or 32) is more robust under 996 * extreme memory and disk pressure because any unnecessary writes 997 * to disk can result in extreme performance degredation. However, 998 * systems with excessive dirty pages (especially when MAP_NOSYNC is 999 * used) will die horribly with limited laundering. If the pageout 1000 * daemon cannot clean enough pages in the first pass, we let it go 1001 * all out in succeeding passes. 1002 */ 1003 if ((maxlaunder = vm_max_launder) <= 1) 1004 maxlaunder = 1; 1005 if (pass > 1) 1006 maxlaunder = 10000; 1007 1008 /* 1009 * Start scanning the inactive queue for pages we can move to the 1010 * cache or free. The scan will stop when the target is reached or 1011 * we have scanned the entire inactive queue. Note that m->act_count 1012 * is not used to form decisions for the inactive queue, only for the 1013 * active queue. 1014 */ 1015 pq = &vmd->vmd_pagequeues[PQ_INACTIVE]; 1016 maxscan = pq->pq_cnt; 1017 vm_pagequeue_lock(pq); 1018 queue_locked = TRUE; 1019 for (m = TAILQ_FIRST(&pq->pq_pl); 1020 m != NULL && maxscan-- > 0 && page_shortage > 0; 1021 m = next) { 1022 vm_pagequeue_assert_locked(pq); 1023 KASSERT(queue_locked, ("unlocked inactive queue")); 1024 KASSERT(m->queue == PQ_INACTIVE, ("Inactive queue %p", m)); 1025 1026 PCPU_INC(cnt.v_pdpages); 1027 next = TAILQ_NEXT(m, plinks.q); 1028 1029 /* 1030 * skip marker pages 1031 */ 1032 if (m->flags & PG_MARKER) 1033 continue; 1034 1035 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1036 ("Fictitious page %p cannot be in inactive queue", m)); 1037 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1038 ("Unmanaged page %p cannot be in inactive queue", m)); 1039 1040 /* 1041 * The page or object lock acquisitions fail if the 1042 * page was removed from the queue or moved to a 1043 * different position within the queue. In either 1044 * case, addl_page_shortage should not be incremented. 1045 */ 1046 if (!vm_pageout_page_lock(m, &next)) { 1047 vm_page_unlock(m); 1048 continue; 1049 } 1050 object = m->object; 1051 if (!VM_OBJECT_TRYWLOCK(object) && 1052 !vm_pageout_fallback_object_lock(m, &next)) { 1053 vm_page_unlock(m); 1054 VM_OBJECT_WUNLOCK(object); 1055 continue; 1056 } 1057 1058 /* 1059 * Don't mess with busy pages, keep them at at the 1060 * front of the queue, most likely they are being 1061 * paged out. Increment addl_page_shortage for busy 1062 * pages, because they may leave the inactive queue 1063 * shortly after page scan is finished. 1064 */ 1065 if (vm_page_busied(m)) { 1066 vm_page_unlock(m); 1067 VM_OBJECT_WUNLOCK(object); 1068 addl_page_shortage++; 1069 continue; 1070 } 1071 1072 /* 1073 * We unlock the inactive page queue, invalidating the 1074 * 'next' pointer. Use our marker to remember our 1075 * place. 1076 */ 1077 TAILQ_INSERT_AFTER(&pq->pq_pl, m, &vmd->vmd_marker, plinks.q); 1078 vm_pagequeue_unlock(pq); 1079 queue_locked = FALSE; 1080 1081 /* 1082 * We bump the activation count if the page has been 1083 * referenced while in the inactive queue. This makes 1084 * it less likely that the page will be added back to the 1085 * inactive queue prematurely again. Here we check the 1086 * page tables (or emulated bits, if any), given the upper 1087 * level VM system not knowing anything about existing 1088 * references. 1089 */ 1090 act_delta = 0; 1091 if ((m->aflags & PGA_REFERENCED) != 0) { 1092 vm_page_aflag_clear(m, PGA_REFERENCED); 1093 act_delta = 1; 1094 } 1095 if (object->ref_count != 0) { 1096 act_delta += pmap_ts_referenced(m); 1097 } else { 1098 KASSERT(!pmap_page_is_mapped(m), 1099 ("vm_pageout_scan: page %p is mapped", m)); 1100 } 1101 1102 /* 1103 * If the upper level VM system knows about any page 1104 * references, we reactivate the page or requeue it. 1105 */ 1106 if (act_delta != 0) { 1107 if (object->ref_count) { 1108 vm_page_activate(m); 1109 m->act_count += act_delta + ACT_ADVANCE; 1110 } else { 1111 vm_pagequeue_lock(pq); 1112 queue_locked = TRUE; 1113 vm_page_requeue_locked(m); 1114 } 1115 VM_OBJECT_WUNLOCK(object); 1116 vm_page_unlock(m); 1117 goto relock_queue; 1118 } 1119 1120 if (m->hold_count != 0) { 1121 vm_page_unlock(m); 1122 VM_OBJECT_WUNLOCK(object); 1123 1124 /* 1125 * Held pages are essentially stuck in the 1126 * queue. So, they ought to be discounted 1127 * from the inactive count. See the 1128 * calculation of the page_shortage for the 1129 * loop over the active queue below. 1130 */ 1131 addl_page_shortage++; 1132 goto relock_queue; 1133 } 1134 1135 /* 1136 * If the page appears to be clean at the machine-independent 1137 * layer, then remove all of its mappings from the pmap in 1138 * anticipation of placing it onto the cache queue. If, 1139 * however, any of the page's mappings allow write access, 1140 * then the page may still be modified until the last of those 1141 * mappings are removed. 1142 */ 1143 if (object->ref_count != 0) { 1144 vm_page_test_dirty(m); 1145 if (m->dirty == 0) 1146 pmap_remove_all(m); 1147 } 1148 1149 if (m->valid == 0) { 1150 /* 1151 * Invalid pages can be easily freed 1152 */ 1153 vm_page_free(m); 1154 PCPU_INC(cnt.v_dfree); 1155 --page_shortage; 1156 } else if (m->dirty == 0) { 1157 /* 1158 * Clean pages can be placed onto the cache queue. 1159 * This effectively frees them. 1160 */ 1161 vm_page_cache(m); 1162 --page_shortage; 1163 } else if ((m->flags & PG_WINATCFLS) == 0 && pass < 2) { 1164 /* 1165 * Dirty pages need to be paged out, but flushing 1166 * a page is extremely expensive verses freeing 1167 * a clean page. Rather then artificially limiting 1168 * the number of pages we can flush, we instead give 1169 * dirty pages extra priority on the inactive queue 1170 * by forcing them to be cycled through the queue 1171 * twice before being flushed, after which the 1172 * (now clean) page will cycle through once more 1173 * before being freed. This significantly extends 1174 * the thrash point for a heavily loaded machine. 1175 */ 1176 m->flags |= PG_WINATCFLS; 1177 vm_pagequeue_lock(pq); 1178 queue_locked = TRUE; 1179 vm_page_requeue_locked(m); 1180 } else if (maxlaunder > 0) { 1181 /* 1182 * We always want to try to flush some dirty pages if 1183 * we encounter them, to keep the system stable. 1184 * Normally this number is small, but under extreme 1185 * pressure where there are insufficient clean pages 1186 * on the inactive queue, we may have to go all out. 1187 */ 1188 int swap_pageouts_ok; 1189 struct vnode *vp = NULL; 1190 struct mount *mp = NULL; 1191 1192 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) { 1193 swap_pageouts_ok = 1; 1194 } else { 1195 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts); 1196 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts && 1197 vm_page_count_min()); 1198 1199 } 1200 1201 /* 1202 * We don't bother paging objects that are "dead". 1203 * Those objects are in a "rundown" state. 1204 */ 1205 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { 1206 vm_pagequeue_lock(pq); 1207 vm_page_unlock(m); 1208 VM_OBJECT_WUNLOCK(object); 1209 queue_locked = TRUE; 1210 vm_page_requeue_locked(m); 1211 goto relock_queue; 1212 } 1213 1214 /* 1215 * The object is already known NOT to be dead. It 1216 * is possible for the vget() to block the whole 1217 * pageout daemon, but the new low-memory handling 1218 * code should prevent it. 1219 * 1220 * The previous code skipped locked vnodes and, worse, 1221 * reordered pages in the queue. This results in 1222 * completely non-deterministic operation and, on a 1223 * busy system, can lead to extremely non-optimal 1224 * pageouts. For example, it can cause clean pages 1225 * to be freed and dirty pages to be moved to the end 1226 * of the queue. Since dirty pages are also moved to 1227 * the end of the queue once-cleaned, this gives 1228 * way too large a weighting to defering the freeing 1229 * of dirty pages. 1230 * 1231 * We can't wait forever for the vnode lock, we might 1232 * deadlock due to a vn_read() getting stuck in 1233 * vm_wait while holding this vnode. We skip the 1234 * vnode if we can't get it in a reasonable amount 1235 * of time. 1236 */ 1237 if (object->type == OBJT_VNODE) { 1238 vm_page_unlock(m); 1239 vp = object->handle; 1240 if (vp->v_type == VREG && 1241 vn_start_write(vp, &mp, V_NOWAIT) != 0) { 1242 mp = NULL; 1243 ++pageout_lock_miss; 1244 if (object->flags & OBJ_MIGHTBEDIRTY) 1245 vnodes_skipped++; 1246 goto unlock_and_continue; 1247 } 1248 KASSERT(mp != NULL, 1249 ("vp %p with NULL v_mount", vp)); 1250 vm_object_reference_locked(object); 1251 VM_OBJECT_WUNLOCK(object); 1252 lockmode = MNT_SHARED_WRITES(vp->v_mount) ? 1253 LK_SHARED : LK_EXCLUSIVE; 1254 if (vget(vp, lockmode | LK_TIMELOCK, 1255 curthread)) { 1256 VM_OBJECT_WLOCK(object); 1257 ++pageout_lock_miss; 1258 if (object->flags & OBJ_MIGHTBEDIRTY) 1259 vnodes_skipped++; 1260 vp = NULL; 1261 goto unlock_and_continue; 1262 } 1263 VM_OBJECT_WLOCK(object); 1264 vm_page_lock(m); 1265 vm_pagequeue_lock(pq); 1266 queue_locked = TRUE; 1267 /* 1268 * The page might have been moved to another 1269 * queue during potential blocking in vget() 1270 * above. The page might have been freed and 1271 * reused for another vnode. 1272 */ 1273 if (m->queue != PQ_INACTIVE || 1274 m->object != object || 1275 TAILQ_NEXT(m, plinks.q) != &vmd->vmd_marker) { 1276 vm_page_unlock(m); 1277 if (object->flags & OBJ_MIGHTBEDIRTY) 1278 vnodes_skipped++; 1279 goto unlock_and_continue; 1280 } 1281 1282 /* 1283 * The page may have been busied during the 1284 * blocking in vget(). We don't move the 1285 * page back onto the end of the queue so that 1286 * statistics are more correct if we don't. 1287 */ 1288 if (vm_page_busied(m)) { 1289 vm_page_unlock(m); 1290 addl_page_shortage++; 1291 goto unlock_and_continue; 1292 } 1293 1294 /* 1295 * If the page has become held it might 1296 * be undergoing I/O, so skip it 1297 */ 1298 if (m->hold_count != 0) { 1299 vm_page_unlock(m); 1300 addl_page_shortage++; 1301 if (object->flags & OBJ_MIGHTBEDIRTY) 1302 vnodes_skipped++; 1303 goto unlock_and_continue; 1304 } 1305 vm_pagequeue_unlock(pq); 1306 queue_locked = FALSE; 1307 } 1308 1309 /* 1310 * If a page is dirty, then it is either being washed 1311 * (but not yet cleaned) or it is still in the 1312 * laundry. If it is still in the laundry, then we 1313 * start the cleaning operation. 1314 * 1315 * decrement page_shortage on success to account for 1316 * the (future) cleaned page. Otherwise we could wind 1317 * up laundering or cleaning too many pages. 1318 */ 1319 if (vm_pageout_clean(m) != 0) { 1320 --page_shortage; 1321 --maxlaunder; 1322 } 1323 unlock_and_continue: 1324 vm_page_lock_assert(m, MA_NOTOWNED); 1325 VM_OBJECT_WUNLOCK(object); 1326 if (mp != NULL) { 1327 if (queue_locked) { 1328 vm_pagequeue_unlock(pq); 1329 queue_locked = FALSE; 1330 } 1331 if (vp != NULL) 1332 vput(vp); 1333 vm_object_deallocate(object); 1334 vn_finished_write(mp); 1335 } 1336 vm_page_lock_assert(m, MA_NOTOWNED); 1337 goto relock_queue; 1338 } 1339 vm_page_unlock(m); 1340 VM_OBJECT_WUNLOCK(object); 1341 relock_queue: 1342 if (!queue_locked) { 1343 vm_pagequeue_lock(pq); 1344 queue_locked = TRUE; 1345 } 1346 next = TAILQ_NEXT(&vmd->vmd_marker, plinks.q); 1347 TAILQ_REMOVE(&pq->pq_pl, &vmd->vmd_marker, plinks.q); 1348 } 1349 vm_pagequeue_unlock(pq); 1350 1351 #if !defined(NO_SWAPPING) 1352 /* 1353 * Wakeup the swapout daemon if we didn't cache or free the targeted 1354 * number of pages. 1355 */ 1356 if (vm_swap_enabled && page_shortage > 0) 1357 vm_req_vmdaemon(VM_SWAP_NORMAL); 1358 #endif 1359 1360 /* 1361 * Wakeup the sync daemon if we skipped a vnode in a writeable object 1362 * and we didn't cache or free enough pages. 1363 */ 1364 if (vnodes_skipped > 0 && page_shortage > cnt.v_free_target - 1365 cnt.v_free_min) 1366 (void)speedup_syncer(); 1367 1368 /* 1369 * If the inactive queue scan fails repeatedly to meet its 1370 * target, kill the largest process. 1371 */ 1372 vm_pageout_mightbe_oom(vmd, page_shortage, starting_page_shortage); 1373 1374 /* 1375 * Compute the number of pages we want to try to move from the 1376 * active queue to the inactive queue. 1377 */ 1378 page_shortage = cnt.v_inactive_target - cnt.v_inactive_count + 1379 vm_paging_target() + deficit + addl_page_shortage; 1380 1381 pq = &vmd->vmd_pagequeues[PQ_ACTIVE]; 1382 vm_pagequeue_lock(pq); 1383 maxscan = pq->pq_cnt; 1384 1385 /* 1386 * If we're just idle polling attempt to visit every 1387 * active page within 'update_period' seconds. 1388 */ 1389 scan_tick = ticks; 1390 if (vm_pageout_update_period != 0) { 1391 min_scan = pq->pq_cnt; 1392 min_scan *= scan_tick - vmd->vmd_last_active_scan; 1393 min_scan /= hz * vm_pageout_update_period; 1394 } else 1395 min_scan = 0; 1396 if (min_scan > 0 || (page_shortage > 0 && maxscan > 0)) 1397 vmd->vmd_last_active_scan = scan_tick; 1398 1399 /* 1400 * Scan the active queue for pages that can be deactivated. Update 1401 * the per-page activity counter and use it to identify deactivation 1402 * candidates. Held pages may be deactivated. 1403 */ 1404 for (m = TAILQ_FIRST(&pq->pq_pl), scanned = 0; m != NULL && (scanned < 1405 min_scan || (page_shortage > 0 && scanned < maxscan)); m = next, 1406 scanned++) { 1407 KASSERT(m->queue == PQ_ACTIVE, 1408 ("vm_pageout_scan: page %p isn't active", m)); 1409 next = TAILQ_NEXT(m, plinks.q); 1410 if ((m->flags & PG_MARKER) != 0) 1411 continue; 1412 KASSERT((m->flags & PG_FICTITIOUS) == 0, 1413 ("Fictitious page %p cannot be in active queue", m)); 1414 KASSERT((m->oflags & VPO_UNMANAGED) == 0, 1415 ("Unmanaged page %p cannot be in active queue", m)); 1416 if (!vm_pageout_page_lock(m, &next)) { 1417 vm_page_unlock(m); 1418 continue; 1419 } 1420 1421 /* 1422 * The count for page daemon pages is updated after checking 1423 * the page for eligibility. 1424 */ 1425 PCPU_INC(cnt.v_pdpages); 1426 1427 /* 1428 * Check to see "how much" the page has been used. 1429 */ 1430 act_delta = 0; 1431 if (m->aflags & PGA_REFERENCED) { 1432 vm_page_aflag_clear(m, PGA_REFERENCED); 1433 act_delta += 1; 1434 } 1435 /* 1436 * Perform an unsynchronized object ref count check. While 1437 * the page lock ensures that the page is not reallocated to 1438 * another object, in particular, one with unmanaged mappings 1439 * that cannot support pmap_ts_referenced(), two races are, 1440 * nonetheless, possible: 1441 * 1) The count was transitioning to zero, but we saw a non- 1442 * zero value. pmap_ts_referenced() will return zero 1443 * because the page is not mapped. 1444 * 2) The count was transitioning to one, but we saw zero. 1445 * This race delays the detection of a new reference. At 1446 * worst, we will deactivate and reactivate the page. 1447 */ 1448 if (m->object->ref_count != 0) 1449 act_delta += pmap_ts_referenced(m); 1450 1451 /* 1452 * Advance or decay the act_count based on recent usage. 1453 */ 1454 if (act_delta) { 1455 m->act_count += ACT_ADVANCE + act_delta; 1456 if (m->act_count > ACT_MAX) 1457 m->act_count = ACT_MAX; 1458 } else { 1459 m->act_count -= min(m->act_count, ACT_DECLINE); 1460 act_delta = m->act_count; 1461 } 1462 1463 /* 1464 * Move this page to the tail of the active or inactive 1465 * queue depending on usage. 1466 */ 1467 if (act_delta == 0) { 1468 /* Dequeue to avoid later lock recursion. */ 1469 vm_page_dequeue_locked(m); 1470 vm_page_deactivate(m); 1471 page_shortage--; 1472 } else 1473 vm_page_requeue_locked(m); 1474 vm_page_unlock(m); 1475 } 1476 vm_pagequeue_unlock(pq); 1477 #if !defined(NO_SWAPPING) 1478 /* 1479 * Idle process swapout -- run once per second. 1480 */ 1481 if (vm_swap_idle_enabled) { 1482 static long lsec; 1483 if (time_second != lsec) { 1484 vm_req_vmdaemon(VM_SWAP_IDLE); 1485 lsec = time_second; 1486 } 1487 } 1488 #endif 1489 } 1490 1491 static int vm_pageout_oom_vote; 1492 1493 /* 1494 * The pagedaemon threads randlomly select one to perform the 1495 * OOM. Trying to kill processes before all pagedaemons 1496 * failed to reach free target is premature. 1497 */ 1498 static void 1499 vm_pageout_mightbe_oom(struct vm_domain *vmd, int page_shortage, 1500 int starting_page_shortage) 1501 { 1502 int old_vote; 1503 1504 if (starting_page_shortage <= 0 || starting_page_shortage != 1505 page_shortage) 1506 vmd->vmd_oom_seq = 0; 1507 else 1508 vmd->vmd_oom_seq++; 1509 if (vmd->vmd_oom_seq < vm_pageout_oom_seq) { 1510 if (vmd->vmd_oom) { 1511 vmd->vmd_oom = FALSE; 1512 atomic_subtract_int(&vm_pageout_oom_vote, 1); 1513 } 1514 return; 1515 } 1516 1517 /* 1518 * Do not follow the call sequence until OOM condition is 1519 * cleared. 1520 */ 1521 vmd->vmd_oom_seq = 0; 1522 1523 if (vmd->vmd_oom) 1524 return; 1525 1526 vmd->vmd_oom = TRUE; 1527 old_vote = atomic_fetchadd_int(&vm_pageout_oom_vote, 1); 1528 if (old_vote != vm_ndomains - 1) 1529 return; 1530 1531 /* 1532 * The current pagedaemon thread is the last in the quorum to 1533 * start OOM. Initiate the selection and signaling of the 1534 * victim. 1535 */ 1536 vm_pageout_oom(VM_OOM_MEM); 1537 1538 /* 1539 * After one round of OOM terror, recall our vote. On the 1540 * next pass, current pagedaemon would vote again if the low 1541 * memory condition is still there, due to vmd_oom being 1542 * false. 1543 */ 1544 vmd->vmd_oom = FALSE; 1545 atomic_subtract_int(&vm_pageout_oom_vote, 1); 1546 } 1547 1548 /* 1549 * The OOM killer is the page daemon's action of last resort when 1550 * memory allocation requests have been stalled for a prolonged period 1551 * of time because it cannot reclaim memory. This function computes 1552 * the approximate number of physical pages that could be reclaimed if 1553 * the specified address space is destroyed. 1554 * 1555 * Private, anonymous memory owned by the address space is the 1556 * principal resource that we expect to recover after an OOM kill. 1557 * Since the physical pages mapped by the address space's COW entries 1558 * are typically shared pages, they are unlikely to be released and so 1559 * they are not counted. 1560 * 1561 * To get to the point where the page daemon runs the OOM killer, its 1562 * efforts to write-back vnode-backed pages may have stalled. This 1563 * could be caused by a memory allocation deadlock in the write path 1564 * that might be resolved by an OOM kill. Therefore, physical pages 1565 * belonging to vnode-backed objects are counted, because they might 1566 * be freed without being written out first if the address space holds 1567 * the last reference to an unlinked vnode. 1568 * 1569 * Similarly, physical pages belonging to OBJT_PHYS objects are 1570 * counted because the address space might hold the last reference to 1571 * the object. 1572 */ 1573 static long 1574 vm_pageout_oom_pagecount(struct vmspace *vmspace) 1575 { 1576 vm_map_t map; 1577 vm_map_entry_t entry; 1578 vm_object_t obj; 1579 long res; 1580 1581 map = &vmspace->vm_map; 1582 KASSERT(!map->system_map, ("system map")); 1583 sx_assert(&map->lock, SA_LOCKED); 1584 res = 0; 1585 for (entry = map->header.next; entry != &map->header; 1586 entry = entry->next) { 1587 if ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) 1588 continue; 1589 obj = entry->object.vm_object; 1590 if (obj == NULL) 1591 continue; 1592 if ((entry->eflags & MAP_ENTRY_NEEDS_COPY) != 0 && 1593 obj->ref_count != 1) 1594 continue; 1595 switch (obj->type) { 1596 case OBJT_DEFAULT: 1597 case OBJT_SWAP: 1598 case OBJT_PHYS: 1599 case OBJT_VNODE: 1600 res += obj->resident_page_count; 1601 break; 1602 } 1603 } 1604 return (res); 1605 } 1606 1607 void 1608 vm_pageout_oom(int shortage) 1609 { 1610 struct proc *p, *bigproc; 1611 vm_offset_t size, bigsize; 1612 struct thread *td; 1613 struct vmspace *vm; 1614 bool breakout; 1615 1616 /* 1617 * We keep the process bigproc locked once we find it to keep anyone 1618 * from messing with it; however, there is a possibility of 1619 * deadlock if process B is bigproc and one of it's child processes 1620 * attempts to propagate a signal to B while we are waiting for A's 1621 * lock while walking this list. To avoid this, we don't block on 1622 * the process lock but just skip a process if it is already locked. 1623 */ 1624 bigproc = NULL; 1625 bigsize = 0; 1626 sx_slock(&allproc_lock); 1627 FOREACH_PROC_IN_SYSTEM(p) { 1628 PROC_LOCK(p); 1629 1630 /* 1631 * If this is a system, protected or killed process, skip it. 1632 */ 1633 if (p->p_state != PRS_NORMAL || (p->p_flag & (P_INEXEC | 1634 P_PROTECTED | P_SYSTEM | P_WEXIT)) != 0 || 1635 p->p_pid == 1 || P_KILLED(p) || 1636 (p->p_pid < 48 && swap_pager_avail != 0)) { 1637 PROC_UNLOCK(p); 1638 continue; 1639 } 1640 /* 1641 * If the process is in a non-running type state, 1642 * don't touch it. Check all the threads individually. 1643 */ 1644 breakout = false; 1645 FOREACH_THREAD_IN_PROC(p, td) { 1646 thread_lock(td); 1647 if (!TD_ON_RUNQ(td) && 1648 !TD_IS_RUNNING(td) && 1649 !TD_IS_SLEEPING(td) && 1650 !TD_IS_SUSPENDED(td) && 1651 !TD_IS_SWAPPED(td)) { 1652 thread_unlock(td); 1653 breakout = true; 1654 break; 1655 } 1656 thread_unlock(td); 1657 } 1658 if (breakout) { 1659 PROC_UNLOCK(p); 1660 continue; 1661 } 1662 /* 1663 * get the process size 1664 */ 1665 vm = vmspace_acquire_ref(p); 1666 if (vm == NULL) { 1667 PROC_UNLOCK(p); 1668 continue; 1669 } 1670 _PHOLD(p); 1671 if (!vm_map_trylock_read(&vm->vm_map)) { 1672 _PRELE(p); 1673 PROC_UNLOCK(p); 1674 vmspace_free(vm); 1675 continue; 1676 } 1677 PROC_UNLOCK(p); 1678 size = vmspace_swap_count(vm); 1679 if (shortage == VM_OOM_MEM) 1680 size += vm_pageout_oom_pagecount(vm); 1681 vm_map_unlock_read(&vm->vm_map); 1682 vmspace_free(vm); 1683 1684 /* 1685 * If this process is bigger than the biggest one, 1686 * remember it. 1687 */ 1688 if (size > bigsize) { 1689 if (bigproc != NULL) 1690 PRELE(bigproc); 1691 bigproc = p; 1692 bigsize = size; 1693 } else { 1694 PRELE(p); 1695 } 1696 } 1697 sx_sunlock(&allproc_lock); 1698 if (bigproc != NULL) { 1699 PROC_LOCK(bigproc); 1700 killproc(bigproc, "out of swap space"); 1701 sched_nice(bigproc, PRIO_MIN); 1702 _PRELE(bigproc); 1703 PROC_UNLOCK(bigproc); 1704 wakeup(&cnt.v_free_count); 1705 } 1706 } 1707 1708 static void 1709 vm_pageout_worker(void *arg) 1710 { 1711 struct vm_domain *domain; 1712 int domidx; 1713 1714 domidx = (uintptr_t)arg; 1715 domain = &vm_dom[domidx]; 1716 1717 /* 1718 * XXXKIB It could be useful to bind pageout daemon threads to 1719 * the cores belonging to the domain, from which vm_page_array 1720 * is allocated. 1721 */ 1722 1723 KASSERT(domain->vmd_segs != 0, ("domain without segments")); 1724 domain->vmd_last_active_scan = ticks; 1725 vm_pageout_init_marker(&domain->vmd_marker, PQ_INACTIVE); 1726 1727 /* 1728 * The pageout daemon worker is never done, so loop forever. 1729 */ 1730 while (TRUE) { 1731 /* 1732 * If we have enough free memory, wakeup waiters. Do 1733 * not clear vm_pages_needed until we reach our target, 1734 * otherwise we may be woken up over and over again and 1735 * waste a lot of cpu. 1736 */ 1737 mtx_lock(&vm_page_queue_free_mtx); 1738 if (vm_pages_needed && !vm_page_count_min()) { 1739 if (!vm_paging_needed()) 1740 vm_pages_needed = 0; 1741 wakeup(&cnt.v_free_count); 1742 } 1743 if (vm_pages_needed) { 1744 /* 1745 * We're still not done. Either vm_pages_needed was 1746 * set by another thread during the previous scan 1747 * (typically, this happens during a level 0 scan) or 1748 * vm_pages_needed was already set and the scan failed 1749 * to free enough pages. If we haven't yet performed 1750 * a level >= 2 scan (unlimited dirty cleaning), then 1751 * upgrade the level and scan again now. Otherwise, 1752 * sleep a bit and try again later. While sleeping, 1753 * vm_pages_needed can be cleared. 1754 */ 1755 if (domain->vmd_pass > 1) 1756 msleep(&vm_pages_needed, 1757 &vm_page_queue_free_mtx, PVM, "psleep", 1758 hz / 2); 1759 } else { 1760 /* 1761 * Good enough, sleep until required to refresh 1762 * stats. 1763 */ 1764 msleep(&vm_pages_needed, &vm_page_queue_free_mtx, 1765 PVM, "psleep", hz); 1766 } 1767 if (vm_pages_needed) { 1768 cnt.v_pdwakeups++; 1769 domain->vmd_pass++; 1770 } else 1771 domain->vmd_pass = 0; 1772 mtx_unlock(&vm_page_queue_free_mtx); 1773 vm_pageout_scan(domain, domain->vmd_pass); 1774 } 1775 } 1776 1777 /* 1778 * vm_pageout_init initialises basic pageout daemon settings. 1779 */ 1780 static void 1781 vm_pageout_init(void) 1782 { 1783 /* 1784 * Initialize some paging parameters. 1785 */ 1786 cnt.v_interrupt_free_min = 2; 1787 if (cnt.v_page_count < 2000) 1788 vm_pageout_page_count = 8; 1789 1790 /* 1791 * v_free_reserved needs to include enough for the largest 1792 * swap pager structures plus enough for any pv_entry structs 1793 * when paging. 1794 */ 1795 if (cnt.v_page_count > 1024) 1796 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; 1797 else 1798 cnt.v_free_min = 4; 1799 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE + 1800 cnt.v_interrupt_free_min; 1801 cnt.v_free_reserved = vm_pageout_page_count + 1802 cnt.v_pageout_free_min + (cnt.v_page_count / 768); 1803 cnt.v_free_severe = cnt.v_free_min / 2; 1804 cnt.v_free_target = 4 * cnt.v_free_min + cnt.v_free_reserved; 1805 cnt.v_free_min += cnt.v_free_reserved; 1806 cnt.v_free_severe += cnt.v_free_reserved; 1807 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2; 1808 if (cnt.v_inactive_target > cnt.v_free_count / 3) 1809 cnt.v_inactive_target = cnt.v_free_count / 3; 1810 1811 /* 1812 * Set the default wakeup threshold to be 10% above the minimum 1813 * page limit. This keeps the steady state out of shortfall. 1814 */ 1815 vm_pageout_wakeup_thresh = (cnt.v_free_min / 10) * 11; 1816 1817 /* 1818 * Set interval in seconds for active scan. We want to visit each 1819 * page at least once every ten minutes. This is to prevent worst 1820 * case paging behaviors with stale active LRU. 1821 */ 1822 if (vm_pageout_update_period == 0) 1823 vm_pageout_update_period = 600; 1824 1825 /* XXX does not really belong here */ 1826 if (vm_page_max_wired == 0) 1827 vm_page_max_wired = cnt.v_free_count / 3; 1828 } 1829 1830 /* 1831 * vm_pageout is the high level pageout daemon. 1832 */ 1833 static void 1834 vm_pageout(void) 1835 { 1836 int error; 1837 #if MAXMEMDOM > 1 1838 int i; 1839 #endif 1840 1841 swap_pager_swap_init(); 1842 #if MAXMEMDOM > 1 1843 for (i = 1; i < vm_ndomains; i++) { 1844 error = kthread_add(vm_pageout_worker, (void *)(uintptr_t)i, 1845 curproc, NULL, 0, 0, "dom%d", i); 1846 if (error != 0) { 1847 panic("starting pageout for domain %d, error %d\n", 1848 i, error); 1849 } 1850 } 1851 #endif 1852 error = kthread_add(uma_reclaim_worker, NULL, curproc, NULL, 1853 0, 0, "uma"); 1854 if (error != 0) 1855 panic("starting uma_reclaim helper, error %d\n", error); 1856 vm_pageout_worker((void *)(uintptr_t)0); 1857 } 1858 1859 /* 1860 * Unless the free page queue lock is held by the caller, this function 1861 * should be regarded as advisory. Specifically, the caller should 1862 * not msleep() on &cnt.v_free_count following this function unless 1863 * the free page queue lock is held until the msleep() is performed. 1864 */ 1865 void 1866 pagedaemon_wakeup(void) 1867 { 1868 1869 if (!vm_pages_needed && curthread->td_proc != pageproc) { 1870 vm_pages_needed = 1; 1871 wakeup(&vm_pages_needed); 1872 } 1873 } 1874 1875 #if !defined(NO_SWAPPING) 1876 static void 1877 vm_req_vmdaemon(int req) 1878 { 1879 static int lastrun = 0; 1880 1881 mtx_lock(&vm_daemon_mtx); 1882 vm_pageout_req_swapout |= req; 1883 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) { 1884 wakeup(&vm_daemon_needed); 1885 lastrun = ticks; 1886 } 1887 mtx_unlock(&vm_daemon_mtx); 1888 } 1889 1890 static void 1891 vm_daemon(void) 1892 { 1893 struct rlimit rsslim; 1894 struct proc *p; 1895 struct thread *td; 1896 struct vmspace *vm; 1897 int breakout, swapout_flags, tryagain, attempts; 1898 #ifdef RACCT 1899 uint64_t rsize, ravailable; 1900 #endif 1901 1902 while (TRUE) { 1903 mtx_lock(&vm_daemon_mtx); 1904 msleep(&vm_daemon_needed, &vm_daemon_mtx, PPAUSE, "psleep", 1905 #ifdef RACCT 1906 racct_enable ? hz : 0 1907 #else 1908 0 1909 #endif 1910 ); 1911 swapout_flags = vm_pageout_req_swapout; 1912 vm_pageout_req_swapout = 0; 1913 mtx_unlock(&vm_daemon_mtx); 1914 if (swapout_flags) 1915 swapout_procs(swapout_flags); 1916 1917 /* 1918 * scan the processes for exceeding their rlimits or if 1919 * process is swapped out -- deactivate pages 1920 */ 1921 tryagain = 0; 1922 attempts = 0; 1923 again: 1924 attempts++; 1925 sx_slock(&allproc_lock); 1926 FOREACH_PROC_IN_SYSTEM(p) { 1927 vm_pindex_t limit, size; 1928 1929 /* 1930 * if this is a system process or if we have already 1931 * looked at this process, skip it. 1932 */ 1933 PROC_LOCK(p); 1934 if (p->p_state != PRS_NORMAL || 1935 p->p_flag & (P_INEXEC | P_SYSTEM | P_WEXIT)) { 1936 PROC_UNLOCK(p); 1937 continue; 1938 } 1939 /* 1940 * if the process is in a non-running type state, 1941 * don't touch it. 1942 */ 1943 breakout = 0; 1944 FOREACH_THREAD_IN_PROC(p, td) { 1945 thread_lock(td); 1946 if (!TD_ON_RUNQ(td) && 1947 !TD_IS_RUNNING(td) && 1948 !TD_IS_SLEEPING(td) && 1949 !TD_IS_SUSPENDED(td)) { 1950 thread_unlock(td); 1951 breakout = 1; 1952 break; 1953 } 1954 thread_unlock(td); 1955 } 1956 if (breakout) { 1957 PROC_UNLOCK(p); 1958 continue; 1959 } 1960 /* 1961 * get a limit 1962 */ 1963 lim_rlimit(p, RLIMIT_RSS, &rsslim); 1964 limit = OFF_TO_IDX( 1965 qmin(rsslim.rlim_cur, rsslim.rlim_max)); 1966 1967 /* 1968 * let processes that are swapped out really be 1969 * swapped out set the limit to nothing (will force a 1970 * swap-out.) 1971 */ 1972 if ((p->p_flag & P_INMEM) == 0) 1973 limit = 0; /* XXX */ 1974 vm = vmspace_acquire_ref(p); 1975 PROC_UNLOCK(p); 1976 if (vm == NULL) 1977 continue; 1978 1979 size = vmspace_resident_count(vm); 1980 if (size >= limit) { 1981 vm_pageout_map_deactivate_pages( 1982 &vm->vm_map, limit); 1983 size = vmspace_resident_count(vm); 1984 } 1985 #ifdef RACCT 1986 if (racct_enable) { 1987 rsize = IDX_TO_OFF(size); 1988 PROC_LOCK(p); 1989 if (p->p_state == PRS_NORMAL) 1990 racct_set(p, RACCT_RSS, rsize); 1991 ravailable = racct_get_available(p, RACCT_RSS); 1992 PROC_UNLOCK(p); 1993 if (rsize > ravailable) { 1994 /* 1995 * Don't be overly aggressive; this 1996 * might be an innocent process, 1997 * and the limit could've been exceeded 1998 * by some memory hog. Don't try 1999 * to deactivate more than 1/4th 2000 * of process' resident set size. 2001 */ 2002 if (attempts <= 8) { 2003 if (ravailable < rsize - 2004 (rsize / 4)) { 2005 ravailable = rsize - 2006 (rsize / 4); 2007 } 2008 } 2009 vm_pageout_map_deactivate_pages( 2010 &vm->vm_map, 2011 OFF_TO_IDX(ravailable)); 2012 /* Update RSS usage after paging out. */ 2013 size = vmspace_resident_count(vm); 2014 rsize = IDX_TO_OFF(size); 2015 PROC_LOCK(p); 2016 if (p->p_state == PRS_NORMAL) 2017 racct_set(p, RACCT_RSS, rsize); 2018 PROC_UNLOCK(p); 2019 if (rsize > ravailable) 2020 tryagain = 1; 2021 } 2022 } 2023 #endif 2024 vmspace_free(vm); 2025 } 2026 sx_sunlock(&allproc_lock); 2027 if (tryagain != 0 && attempts <= 10) 2028 goto again; 2029 } 2030 } 2031 #endif /* !defined(NO_SWAPPING) */
Cache object: a17cea8b9b500d3058f9c187cc24597f
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