69 */ 70 71/* 72 * The proverbial page-out daemon. 73 */ 74 75#include "opt_vm.h" 76#include <sys/param.h> 77#include <sys/systm.h> 78#include <sys/kernel.h> 79#include <sys/lock.h> 80#include <sys/mutex.h> 81#include <sys/proc.h> 82#include <sys/kthread.h> 83#include <sys/ktr.h> 84#include <sys/resourcevar.h> 85#include <sys/signalvar.h> 86#include <sys/vnode.h> 87#include <sys/vmmeter.h> 88#include <sys/sx.h> 89#include <sys/sysctl.h> 90 91#include <vm/vm.h> 92#include <vm/vm_param.h> 93#include <vm/vm_object.h> 94#include <vm/vm_page.h> 95#include <vm/vm_map.h> 96#include <vm/vm_pageout.h> 97#include <vm/vm_pager.h> 98#include <vm/vm_zone.h> 99#include <vm/swap_pager.h> 100#include <vm/vm_extern.h> 101 102#include <machine/mutex.h> 103 104/* 105 * System initialization 106 */ 107 108/* the kernel process "vm_pageout"*/ 109static void vm_pageout __P((void)); 110static int vm_pageout_clean __P((vm_page_t)); 111static void vm_pageout_scan __P((int pass)); 112static int vm_pageout_free_page_calc __P((vm_size_t count)); 113struct proc *pageproc; 114 115static struct kproc_desc page_kp = { 116 "pagedaemon", 117 vm_pageout, 118 &pageproc 119}; 120SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp) 121 122#if !defined(NO_SWAPPING) 123/* the kernel process "vm_daemon"*/ 124static void vm_daemon __P((void)); 125static struct proc *vmproc; 126 127static struct kproc_desc vm_kp = { 128 "vmdaemon", 129 vm_daemon, 130 &vmproc 131}; 132SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp) 133#endif 134 135 136int vm_pages_needed=0; /* Event on which pageout daemon sleeps */ 137int vm_pageout_deficit=0; /* Estimated number of pages deficit */ 138int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */ 139 140#if !defined(NO_SWAPPING) 141static int vm_pageout_req_swapout; /* XXX */ 142static int vm_daemon_needed; 143#endif 144extern int vm_swap_size; 145static int vm_max_launder = 32; 146static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0; 147static int vm_pageout_full_stats_interval = 0; 148static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0; 149static int defer_swap_pageouts=0; 150static int disable_swap_pageouts=0; 151 152#if defined(NO_SWAPPING) 153static int vm_swap_enabled=0; 154static int vm_swap_idle_enabled=0; 155#else 156static int vm_swap_enabled=1; 157static int vm_swap_idle_enabled=0; 158#endif 159 160SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm, 161 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt"); 162 163SYSCTL_INT(_vm, OID_AUTO, max_launder, 164 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout"); 165 166SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max, 167 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length"); 168 169SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval, 170 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan"); 171 172SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval, 173 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan"); 174 175SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max, 176 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented"); 177 178#if defined(NO_SWAPPING) 179SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 180 CTLFLAG_RD, &vm_swap_enabled, 0, ""); 181SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 182 CTLFLAG_RD, &vm_swap_idle_enabled, 0, ""); 183#else 184SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 185 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout"); 186SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 187 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 188#endif 189 190SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts, 191 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem"); 192 193SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts, 194 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages"); 195 196static int pageout_lock_miss; 197SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss, 198 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout"); 199 200#define VM_PAGEOUT_PAGE_COUNT 16 201int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 202 203int vm_page_max_wired; /* XXX max # of wired pages system-wide */ 204 205#if !defined(NO_SWAPPING) 206typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int)); 207static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t)); 208static freeer_fcn_t vm_pageout_object_deactivate_pages; 209static void vm_req_vmdaemon __P((void)); 210#endif 211static void vm_pageout_page_stats(void); 212 213/* 214 * vm_pageout_clean: 215 * 216 * Clean the page and remove it from the laundry. 217 * 218 * We set the busy bit to cause potential page faults on this page to 219 * block. Note the careful timing, however, the busy bit isn't set till 220 * late and we cannot do anything that will mess with the page. 221 */ 222static int 223vm_pageout_clean(m) 224 vm_page_t m; 225{ 226 vm_object_t object; 227 vm_page_t mc[2*vm_pageout_page_count]; 228 int pageout_count; 229 int ib, is, page_base; 230 vm_pindex_t pindex = m->pindex; 231 232 GIANT_REQUIRED; 233 234 object = m->object; 235 236 /* 237 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP 238 * with the new swapper, but we could have serious problems paging 239 * out other object types if there is insufficient memory. 240 * 241 * Unfortunately, checking free memory here is far too late, so the 242 * check has been moved up a procedural level. 243 */ 244 245 /* 246 * Don't mess with the page if it's busy, held, or special 247 */ 248 if ((m->hold_count != 0) || 249 ((m->busy != 0) || (m->flags & (PG_BUSY|PG_UNMANAGED)))) { 250 return 0; 251 } 252 253 mc[vm_pageout_page_count] = m; 254 pageout_count = 1; 255 page_base = vm_pageout_page_count; 256 ib = 1; 257 is = 1; 258 259 /* 260 * Scan object for clusterable pages. 261 * 262 * We can cluster ONLY if: ->> the page is NOT 263 * clean, wired, busy, held, or mapped into a 264 * buffer, and one of the following: 265 * 1) The page is inactive, or a seldom used 266 * active page. 267 * -or- 268 * 2) we force the issue. 269 * 270 * During heavy mmap/modification loads the pageout 271 * daemon can really fragment the underlying file 272 * due to flushing pages out of order and not trying 273 * align the clusters (which leave sporatic out-of-order 274 * holes). To solve this problem we do the reverse scan 275 * first and attempt to align our cluster, then do a 276 * forward scan if room remains. 277 */ 278more: 279 while (ib && pageout_count < vm_pageout_page_count) { 280 vm_page_t p; 281 282 if (ib > pindex) { 283 ib = 0; 284 break; 285 } 286 287 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) { 288 ib = 0; 289 break; 290 } 291 if (((p->queue - p->pc) == PQ_CACHE) || 292 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 293 ib = 0; 294 break; 295 } 296 vm_page_test_dirty(p); 297 if ((p->dirty & p->valid) == 0 || 298 p->queue != PQ_INACTIVE || 299 p->wire_count != 0 || /* may be held by buf cache */ 300 p->hold_count != 0) { /* may be undergoing I/O */ 301 ib = 0; 302 break; 303 } 304 mc[--page_base] = p; 305 ++pageout_count; 306 ++ib; 307 /* 308 * alignment boundry, stop here and switch directions. Do 309 * not clear ib. 310 */ 311 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0) 312 break; 313 } 314 315 while (pageout_count < vm_pageout_page_count && 316 pindex + is < object->size) { 317 vm_page_t p; 318 319 if ((p = vm_page_lookup(object, pindex + is)) == NULL) 320 break; 321 if (((p->queue - p->pc) == PQ_CACHE) || 322 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 323 break; 324 } 325 vm_page_test_dirty(p); 326 if ((p->dirty & p->valid) == 0 || 327 p->queue != PQ_INACTIVE || 328 p->wire_count != 0 || /* may be held by buf cache */ 329 p->hold_count != 0) { /* may be undergoing I/O */ 330 break; 331 } 332 mc[page_base + pageout_count] = p; 333 ++pageout_count; 334 ++is; 335 } 336 337 /* 338 * If we exhausted our forward scan, continue with the reverse scan 339 * when possible, even past a page boundry. This catches boundry 340 * conditions. 341 */ 342 if (ib && pageout_count < vm_pageout_page_count) 343 goto more; 344 345 /* 346 * we allow reads during pageouts... 347 */ 348 return vm_pageout_flush(&mc[page_base], pageout_count, 0); 349} 350 351/* 352 * vm_pageout_flush() - launder the given pages 353 * 354 * The given pages are laundered. Note that we setup for the start of 355 * I/O ( i.e. busy the page ), mark it read-only, and bump the object 356 * reference count all in here rather then in the parent. If we want 357 * the parent to do more sophisticated things we may have to change 358 * the ordering. 359 */ 360int 361vm_pageout_flush(mc, count, flags) 362 vm_page_t *mc; 363 int count; 364 int flags; 365{ 366 vm_object_t object; 367 int pageout_status[count]; 368 int numpagedout = 0; 369 int i; 370 371 GIANT_REQUIRED; 372 /* 373 * Initiate I/O. Bump the vm_page_t->busy counter and 374 * mark the pages read-only. 375 * 376 * We do not have to fixup the clean/dirty bits here... we can 377 * allow the pager to do it after the I/O completes. 378 * 379 * NOTE! mc[i]->dirty may be partial or fragmented due to an 380 * edge case with file fragments. 381 */ 382 for (i = 0; i < count; i++) { 383 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count)); 384 vm_page_io_start(mc[i]); 385 vm_page_protect(mc[i], VM_PROT_READ); 386 } 387 388 object = mc[0]->object; 389 vm_object_pip_add(object, count); 390 391 vm_pager_put_pages(object, mc, count, 392 (flags | ((object == kernel_object) ? OBJPC_SYNC : 0)), 393 pageout_status); 394 395 for (i = 0; i < count; i++) { 396 vm_page_t mt = mc[i]; 397 398 switch (pageout_status[i]) { 399 case VM_PAGER_OK: 400 numpagedout++; 401 break; 402 case VM_PAGER_PEND: 403 numpagedout++; 404 break; 405 case VM_PAGER_BAD: 406 /* 407 * Page outside of range of object. Right now we 408 * essentially lose the changes by pretending it 409 * worked. 410 */ 411 pmap_clear_modify(mt); 412 vm_page_undirty(mt); 413 break; 414 case VM_PAGER_ERROR: 415 case VM_PAGER_FAIL: 416 /* 417 * If page couldn't be paged out, then reactivate the 418 * page so it doesn't clog the inactive list. (We 419 * will try paging out it again later). 420 */ 421 vm_page_activate(mt); 422 break; 423 case VM_PAGER_AGAIN: 424 break; 425 } 426 427 /* 428 * If the operation is still going, leave the page busy to 429 * block all other accesses. Also, leave the paging in 430 * progress indicator set so that we don't attempt an object 431 * collapse. 432 */ 433 if (pageout_status[i] != VM_PAGER_PEND) { 434 vm_object_pip_wakeup(object); 435 vm_page_io_finish(mt); 436 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt)) 437 vm_page_protect(mt, VM_PROT_READ); 438 } 439 } 440 return numpagedout; 441} 442 443#if !defined(NO_SWAPPING) 444/* 445 * vm_pageout_object_deactivate_pages 446 * 447 * deactivate enough pages to satisfy the inactive target 448 * requirements or if vm_page_proc_limit is set, then 449 * deactivate all of the pages in the object and its 450 * backing_objects. 451 * 452 * The object and map must be locked. 453 */ 454static void 455vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only) 456 vm_map_t map; 457 vm_object_t object; 458 vm_pindex_t desired; 459 int map_remove_only; 460{ 461 vm_page_t p, next; 462 int rcount; 463 int remove_mode; 464 465 GIANT_REQUIRED; 466 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS) 467 return; 468 469 while (object) { 470 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 471 return; 472 if (object->paging_in_progress) 473 return; 474 475 remove_mode = map_remove_only; 476 if (object->shadow_count > 1) 477 remove_mode = 1; 478 /* 479 * scan the objects entire memory queue 480 */ 481 rcount = object->resident_page_count; 482 p = TAILQ_FIRST(&object->memq); 483 while (p && (rcount-- > 0)) { 484 int actcount; 485 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 486 return; 487 next = TAILQ_NEXT(p, listq); 488 cnt.v_pdpages++; 489 if (p->wire_count != 0 || 490 p->hold_count != 0 || 491 p->busy != 0 || 492 (p->flags & (PG_BUSY|PG_UNMANAGED)) || 493 !pmap_page_exists_quick(vm_map_pmap(map), p)) { 494 p = next; 495 continue; 496 } 497 498 actcount = pmap_ts_referenced(p); 499 if (actcount) { 500 vm_page_flag_set(p, PG_REFERENCED); 501 } else if (p->flags & PG_REFERENCED) { 502 actcount = 1; 503 } 504 505 if ((p->queue != PQ_ACTIVE) && 506 (p->flags & PG_REFERENCED)) { 507 vm_page_activate(p); 508 p->act_count += actcount; 509 vm_page_flag_clear(p, PG_REFERENCED); 510 } else if (p->queue == PQ_ACTIVE) { 511 if ((p->flags & PG_REFERENCED) == 0) { 512 p->act_count -= min(p->act_count, ACT_DECLINE); 513 if (!remove_mode && (vm_pageout_algorithm || (p->act_count == 0))) { 514 vm_page_protect(p, VM_PROT_NONE); 515 vm_page_deactivate(p); 516 } else { 517 vm_pageq_requeue(p); 518 } 519 } else { 520 vm_page_activate(p); 521 vm_page_flag_clear(p, PG_REFERENCED); 522 if (p->act_count < (ACT_MAX - ACT_ADVANCE)) 523 p->act_count += ACT_ADVANCE; 524 vm_pageq_requeue(p); 525 } 526 } else if (p->queue == PQ_INACTIVE) { 527 vm_page_protect(p, VM_PROT_NONE); 528 } 529 p = next; 530 } 531 object = object->backing_object; 532 } 533 return; 534} 535 536/* 537 * deactivate some number of pages in a map, try to do it fairly, but 538 * that is really hard to do. 539 */ 540static void 541vm_pageout_map_deactivate_pages(map, desired) 542 vm_map_t map; 543 vm_pindex_t desired; 544{ 545 vm_map_entry_t tmpe; 546 vm_object_t obj, bigobj; 547 int nothingwired; 548 549 GIANT_REQUIRED; 550 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, (void *)0, curthread)) { 551 return; 552 } 553 554 bigobj = NULL; 555 nothingwired = TRUE; 556 557 /* 558 * first, search out the biggest object, and try to free pages from 559 * that. 560 */ 561 tmpe = map->header.next; 562 while (tmpe != &map->header) { 563 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 564 obj = tmpe->object.vm_object; 565 if ((obj != NULL) && (obj->shadow_count <= 1) && 566 ((bigobj == NULL) || 567 (bigobj->resident_page_count < obj->resident_page_count))) { 568 bigobj = obj; 569 } 570 } 571 if (tmpe->wired_count > 0) 572 nothingwired = FALSE; 573 tmpe = tmpe->next; 574 } 575 576 if (bigobj) 577 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0); 578 579 /* 580 * Next, hunt around for other pages to deactivate. We actually 581 * do this search sort of wrong -- .text first is not the best idea. 582 */ 583 tmpe = map->header.next; 584 while (tmpe != &map->header) { 585 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 586 break; 587 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 588 obj = tmpe->object.vm_object; 589 if (obj) 590 vm_pageout_object_deactivate_pages(map, obj, desired, 0); 591 } 592 tmpe = tmpe->next; 593 }; 594 595 /* 596 * Remove all mappings if a process is swapped out, this will free page 597 * table pages. 598 */ 599 if (desired == 0 && nothingwired) 600 pmap_remove(vm_map_pmap(map), 601 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); 602 vm_map_unlock(map); 603 return; 604} 605#endif /* !defined(NO_SWAPPING) */ 606 607/* 608 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore 609 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects 610 * which we know can be trivially freed. 611 */ 612void 613vm_pageout_page_free(vm_page_t m) { 614 vm_object_t object = m->object; 615 int type = object->type; 616 617 GIANT_REQUIRED; 618 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 619 vm_object_reference(object); 620 vm_page_busy(m); 621 vm_page_protect(m, VM_PROT_NONE); 622 vm_page_free(m); 623 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 624 vm_object_deallocate(object); 625} 626 627/* 628 * vm_pageout_scan does the dirty work for the pageout daemon. 629 */ 630static void 631vm_pageout_scan(int pass) 632{ 633 vm_page_t m, next; 634 struct vm_page marker; 635 int save_page_shortage; 636 int save_inactive_count; 637 int page_shortage, maxscan, pcount; 638 int addl_page_shortage, addl_page_shortage_init; 639 struct proc *p, *bigproc; 640 vm_offset_t size, bigsize; 641 vm_object_t object; 642 int actcount; 643 int vnodes_skipped = 0; 644 int maxlaunder; 645 int s; 646 647 GIANT_REQUIRED; 648 /* 649 * Do whatever cleanup that the pmap code can. 650 */ 651 pmap_collect();
| 69 */ 70 71/* 72 * The proverbial page-out daemon. 73 */ 74 75#include "opt_vm.h" 76#include <sys/param.h> 77#include <sys/systm.h> 78#include <sys/kernel.h> 79#include <sys/lock.h> 80#include <sys/mutex.h> 81#include <sys/proc.h> 82#include <sys/kthread.h> 83#include <sys/ktr.h> 84#include <sys/resourcevar.h> 85#include <sys/signalvar.h> 86#include <sys/vnode.h> 87#include <sys/vmmeter.h> 88#include <sys/sx.h> 89#include <sys/sysctl.h> 90 91#include <vm/vm.h> 92#include <vm/vm_param.h> 93#include <vm/vm_object.h> 94#include <vm/vm_page.h> 95#include <vm/vm_map.h> 96#include <vm/vm_pageout.h> 97#include <vm/vm_pager.h> 98#include <vm/vm_zone.h> 99#include <vm/swap_pager.h> 100#include <vm/vm_extern.h> 101 102#include <machine/mutex.h> 103 104/* 105 * System initialization 106 */ 107 108/* the kernel process "vm_pageout"*/ 109static void vm_pageout __P((void)); 110static int vm_pageout_clean __P((vm_page_t)); 111static void vm_pageout_scan __P((int pass)); 112static int vm_pageout_free_page_calc __P((vm_size_t count)); 113struct proc *pageproc; 114 115static struct kproc_desc page_kp = { 116 "pagedaemon", 117 vm_pageout, 118 &pageproc 119}; 120SYSINIT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp) 121 122#if !defined(NO_SWAPPING) 123/* the kernel process "vm_daemon"*/ 124static void vm_daemon __P((void)); 125static struct proc *vmproc; 126 127static struct kproc_desc vm_kp = { 128 "vmdaemon", 129 vm_daemon, 130 &vmproc 131}; 132SYSINIT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp) 133#endif 134 135 136int vm_pages_needed=0; /* Event on which pageout daemon sleeps */ 137int vm_pageout_deficit=0; /* Estimated number of pages deficit */ 138int vm_pageout_pages_needed=0; /* flag saying that the pageout daemon needs pages */ 139 140#if !defined(NO_SWAPPING) 141static int vm_pageout_req_swapout; /* XXX */ 142static int vm_daemon_needed; 143#endif 144extern int vm_swap_size; 145static int vm_max_launder = 32; 146static int vm_pageout_stats_max=0, vm_pageout_stats_interval = 0; 147static int vm_pageout_full_stats_interval = 0; 148static int vm_pageout_stats_free_max=0, vm_pageout_algorithm=0; 149static int defer_swap_pageouts=0; 150static int disable_swap_pageouts=0; 151 152#if defined(NO_SWAPPING) 153static int vm_swap_enabled=0; 154static int vm_swap_idle_enabled=0; 155#else 156static int vm_swap_enabled=1; 157static int vm_swap_idle_enabled=0; 158#endif 159 160SYSCTL_INT(_vm, VM_PAGEOUT_ALGORITHM, pageout_algorithm, 161 CTLFLAG_RW, &vm_pageout_algorithm, 0, "LRU page mgmt"); 162 163SYSCTL_INT(_vm, OID_AUTO, max_launder, 164 CTLFLAG_RW, &vm_max_launder, 0, "Limit dirty flushes in pageout"); 165 166SYSCTL_INT(_vm, OID_AUTO, pageout_stats_max, 167 CTLFLAG_RW, &vm_pageout_stats_max, 0, "Max pageout stats scan length"); 168 169SYSCTL_INT(_vm, OID_AUTO, pageout_full_stats_interval, 170 CTLFLAG_RW, &vm_pageout_full_stats_interval, 0, "Interval for full stats scan"); 171 172SYSCTL_INT(_vm, OID_AUTO, pageout_stats_interval, 173 CTLFLAG_RW, &vm_pageout_stats_interval, 0, "Interval for partial stats scan"); 174 175SYSCTL_INT(_vm, OID_AUTO, pageout_stats_free_max, 176 CTLFLAG_RW, &vm_pageout_stats_free_max, 0, "Not implemented"); 177 178#if defined(NO_SWAPPING) 179SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 180 CTLFLAG_RD, &vm_swap_enabled, 0, ""); 181SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 182 CTLFLAG_RD, &vm_swap_idle_enabled, 0, ""); 183#else 184SYSCTL_INT(_vm, VM_SWAPPING_ENABLED, swap_enabled, 185 CTLFLAG_RW, &vm_swap_enabled, 0, "Enable entire process swapout"); 186SYSCTL_INT(_vm, OID_AUTO, swap_idle_enabled, 187 CTLFLAG_RW, &vm_swap_idle_enabled, 0, "Allow swapout on idle criteria"); 188#endif 189 190SYSCTL_INT(_vm, OID_AUTO, defer_swapspace_pageouts, 191 CTLFLAG_RW, &defer_swap_pageouts, 0, "Give preference to dirty pages in mem"); 192 193SYSCTL_INT(_vm, OID_AUTO, disable_swapspace_pageouts, 194 CTLFLAG_RW, &disable_swap_pageouts, 0, "Disallow swapout of dirty pages"); 195 196static int pageout_lock_miss; 197SYSCTL_INT(_vm, OID_AUTO, pageout_lock_miss, 198 CTLFLAG_RD, &pageout_lock_miss, 0, "vget() lock misses during pageout"); 199 200#define VM_PAGEOUT_PAGE_COUNT 16 201int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; 202 203int vm_page_max_wired; /* XXX max # of wired pages system-wide */ 204 205#if !defined(NO_SWAPPING) 206typedef void freeer_fcn_t __P((vm_map_t, vm_object_t, vm_pindex_t, int)); 207static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_pindex_t)); 208static freeer_fcn_t vm_pageout_object_deactivate_pages; 209static void vm_req_vmdaemon __P((void)); 210#endif 211static void vm_pageout_page_stats(void); 212 213/* 214 * vm_pageout_clean: 215 * 216 * Clean the page and remove it from the laundry. 217 * 218 * We set the busy bit to cause potential page faults on this page to 219 * block. Note the careful timing, however, the busy bit isn't set till 220 * late and we cannot do anything that will mess with the page. 221 */ 222static int 223vm_pageout_clean(m) 224 vm_page_t m; 225{ 226 vm_object_t object; 227 vm_page_t mc[2*vm_pageout_page_count]; 228 int pageout_count; 229 int ib, is, page_base; 230 vm_pindex_t pindex = m->pindex; 231 232 GIANT_REQUIRED; 233 234 object = m->object; 235 236 /* 237 * It doesn't cost us anything to pageout OBJT_DEFAULT or OBJT_SWAP 238 * with the new swapper, but we could have serious problems paging 239 * out other object types if there is insufficient memory. 240 * 241 * Unfortunately, checking free memory here is far too late, so the 242 * check has been moved up a procedural level. 243 */ 244 245 /* 246 * Don't mess with the page if it's busy, held, or special 247 */ 248 if ((m->hold_count != 0) || 249 ((m->busy != 0) || (m->flags & (PG_BUSY|PG_UNMANAGED)))) { 250 return 0; 251 } 252 253 mc[vm_pageout_page_count] = m; 254 pageout_count = 1; 255 page_base = vm_pageout_page_count; 256 ib = 1; 257 is = 1; 258 259 /* 260 * Scan object for clusterable pages. 261 * 262 * We can cluster ONLY if: ->> the page is NOT 263 * clean, wired, busy, held, or mapped into a 264 * buffer, and one of the following: 265 * 1) The page is inactive, or a seldom used 266 * active page. 267 * -or- 268 * 2) we force the issue. 269 * 270 * During heavy mmap/modification loads the pageout 271 * daemon can really fragment the underlying file 272 * due to flushing pages out of order and not trying 273 * align the clusters (which leave sporatic out-of-order 274 * holes). To solve this problem we do the reverse scan 275 * first and attempt to align our cluster, then do a 276 * forward scan if room remains. 277 */ 278more: 279 while (ib && pageout_count < vm_pageout_page_count) { 280 vm_page_t p; 281 282 if (ib > pindex) { 283 ib = 0; 284 break; 285 } 286 287 if ((p = vm_page_lookup(object, pindex - ib)) == NULL) { 288 ib = 0; 289 break; 290 } 291 if (((p->queue - p->pc) == PQ_CACHE) || 292 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 293 ib = 0; 294 break; 295 } 296 vm_page_test_dirty(p); 297 if ((p->dirty & p->valid) == 0 || 298 p->queue != PQ_INACTIVE || 299 p->wire_count != 0 || /* may be held by buf cache */ 300 p->hold_count != 0) { /* may be undergoing I/O */ 301 ib = 0; 302 break; 303 } 304 mc[--page_base] = p; 305 ++pageout_count; 306 ++ib; 307 /* 308 * alignment boundry, stop here and switch directions. Do 309 * not clear ib. 310 */ 311 if ((pindex - (ib - 1)) % vm_pageout_page_count == 0) 312 break; 313 } 314 315 while (pageout_count < vm_pageout_page_count && 316 pindex + is < object->size) { 317 vm_page_t p; 318 319 if ((p = vm_page_lookup(object, pindex + is)) == NULL) 320 break; 321 if (((p->queue - p->pc) == PQ_CACHE) || 322 (p->flags & (PG_BUSY|PG_UNMANAGED)) || p->busy) { 323 break; 324 } 325 vm_page_test_dirty(p); 326 if ((p->dirty & p->valid) == 0 || 327 p->queue != PQ_INACTIVE || 328 p->wire_count != 0 || /* may be held by buf cache */ 329 p->hold_count != 0) { /* may be undergoing I/O */ 330 break; 331 } 332 mc[page_base + pageout_count] = p; 333 ++pageout_count; 334 ++is; 335 } 336 337 /* 338 * If we exhausted our forward scan, continue with the reverse scan 339 * when possible, even past a page boundry. This catches boundry 340 * conditions. 341 */ 342 if (ib && pageout_count < vm_pageout_page_count) 343 goto more; 344 345 /* 346 * we allow reads during pageouts... 347 */ 348 return vm_pageout_flush(&mc[page_base], pageout_count, 0); 349} 350 351/* 352 * vm_pageout_flush() - launder the given pages 353 * 354 * The given pages are laundered. Note that we setup for the start of 355 * I/O ( i.e. busy the page ), mark it read-only, and bump the object 356 * reference count all in here rather then in the parent. If we want 357 * the parent to do more sophisticated things we may have to change 358 * the ordering. 359 */ 360int 361vm_pageout_flush(mc, count, flags) 362 vm_page_t *mc; 363 int count; 364 int flags; 365{ 366 vm_object_t object; 367 int pageout_status[count]; 368 int numpagedout = 0; 369 int i; 370 371 GIANT_REQUIRED; 372 /* 373 * Initiate I/O. Bump the vm_page_t->busy counter and 374 * mark the pages read-only. 375 * 376 * We do not have to fixup the clean/dirty bits here... we can 377 * allow the pager to do it after the I/O completes. 378 * 379 * NOTE! mc[i]->dirty may be partial or fragmented due to an 380 * edge case with file fragments. 381 */ 382 for (i = 0; i < count; i++) { 383 KASSERT(mc[i]->valid == VM_PAGE_BITS_ALL, ("vm_pageout_flush page %p index %d/%d: partially invalid page", mc[i], i, count)); 384 vm_page_io_start(mc[i]); 385 vm_page_protect(mc[i], VM_PROT_READ); 386 } 387 388 object = mc[0]->object; 389 vm_object_pip_add(object, count); 390 391 vm_pager_put_pages(object, mc, count, 392 (flags | ((object == kernel_object) ? OBJPC_SYNC : 0)), 393 pageout_status); 394 395 for (i = 0; i < count; i++) { 396 vm_page_t mt = mc[i]; 397 398 switch (pageout_status[i]) { 399 case VM_PAGER_OK: 400 numpagedout++; 401 break; 402 case VM_PAGER_PEND: 403 numpagedout++; 404 break; 405 case VM_PAGER_BAD: 406 /* 407 * Page outside of range of object. Right now we 408 * essentially lose the changes by pretending it 409 * worked. 410 */ 411 pmap_clear_modify(mt); 412 vm_page_undirty(mt); 413 break; 414 case VM_PAGER_ERROR: 415 case VM_PAGER_FAIL: 416 /* 417 * If page couldn't be paged out, then reactivate the 418 * page so it doesn't clog the inactive list. (We 419 * will try paging out it again later). 420 */ 421 vm_page_activate(mt); 422 break; 423 case VM_PAGER_AGAIN: 424 break; 425 } 426 427 /* 428 * If the operation is still going, leave the page busy to 429 * block all other accesses. Also, leave the paging in 430 * progress indicator set so that we don't attempt an object 431 * collapse. 432 */ 433 if (pageout_status[i] != VM_PAGER_PEND) { 434 vm_object_pip_wakeup(object); 435 vm_page_io_finish(mt); 436 if (!vm_page_count_severe() || !vm_page_try_to_cache(mt)) 437 vm_page_protect(mt, VM_PROT_READ); 438 } 439 } 440 return numpagedout; 441} 442 443#if !defined(NO_SWAPPING) 444/* 445 * vm_pageout_object_deactivate_pages 446 * 447 * deactivate enough pages to satisfy the inactive target 448 * requirements or if vm_page_proc_limit is set, then 449 * deactivate all of the pages in the object and its 450 * backing_objects. 451 * 452 * The object and map must be locked. 453 */ 454static void 455vm_pageout_object_deactivate_pages(map, object, desired, map_remove_only) 456 vm_map_t map; 457 vm_object_t object; 458 vm_pindex_t desired; 459 int map_remove_only; 460{ 461 vm_page_t p, next; 462 int rcount; 463 int remove_mode; 464 465 GIANT_REQUIRED; 466 if (object->type == OBJT_DEVICE || object->type == OBJT_PHYS) 467 return; 468 469 while (object) { 470 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 471 return; 472 if (object->paging_in_progress) 473 return; 474 475 remove_mode = map_remove_only; 476 if (object->shadow_count > 1) 477 remove_mode = 1; 478 /* 479 * scan the objects entire memory queue 480 */ 481 rcount = object->resident_page_count; 482 p = TAILQ_FIRST(&object->memq); 483 while (p && (rcount-- > 0)) { 484 int actcount; 485 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 486 return; 487 next = TAILQ_NEXT(p, listq); 488 cnt.v_pdpages++; 489 if (p->wire_count != 0 || 490 p->hold_count != 0 || 491 p->busy != 0 || 492 (p->flags & (PG_BUSY|PG_UNMANAGED)) || 493 !pmap_page_exists_quick(vm_map_pmap(map), p)) { 494 p = next; 495 continue; 496 } 497 498 actcount = pmap_ts_referenced(p); 499 if (actcount) { 500 vm_page_flag_set(p, PG_REFERENCED); 501 } else if (p->flags & PG_REFERENCED) { 502 actcount = 1; 503 } 504 505 if ((p->queue != PQ_ACTIVE) && 506 (p->flags & PG_REFERENCED)) { 507 vm_page_activate(p); 508 p->act_count += actcount; 509 vm_page_flag_clear(p, PG_REFERENCED); 510 } else if (p->queue == PQ_ACTIVE) { 511 if ((p->flags & PG_REFERENCED) == 0) { 512 p->act_count -= min(p->act_count, ACT_DECLINE); 513 if (!remove_mode && (vm_pageout_algorithm || (p->act_count == 0))) { 514 vm_page_protect(p, VM_PROT_NONE); 515 vm_page_deactivate(p); 516 } else { 517 vm_pageq_requeue(p); 518 } 519 } else { 520 vm_page_activate(p); 521 vm_page_flag_clear(p, PG_REFERENCED); 522 if (p->act_count < (ACT_MAX - ACT_ADVANCE)) 523 p->act_count += ACT_ADVANCE; 524 vm_pageq_requeue(p); 525 } 526 } else if (p->queue == PQ_INACTIVE) { 527 vm_page_protect(p, VM_PROT_NONE); 528 } 529 p = next; 530 } 531 object = object->backing_object; 532 } 533 return; 534} 535 536/* 537 * deactivate some number of pages in a map, try to do it fairly, but 538 * that is really hard to do. 539 */ 540static void 541vm_pageout_map_deactivate_pages(map, desired) 542 vm_map_t map; 543 vm_pindex_t desired; 544{ 545 vm_map_entry_t tmpe; 546 vm_object_t obj, bigobj; 547 int nothingwired; 548 549 GIANT_REQUIRED; 550 if (lockmgr(&map->lock, LK_EXCLUSIVE | LK_NOWAIT, (void *)0, curthread)) { 551 return; 552 } 553 554 bigobj = NULL; 555 nothingwired = TRUE; 556 557 /* 558 * first, search out the biggest object, and try to free pages from 559 * that. 560 */ 561 tmpe = map->header.next; 562 while (tmpe != &map->header) { 563 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 564 obj = tmpe->object.vm_object; 565 if ((obj != NULL) && (obj->shadow_count <= 1) && 566 ((bigobj == NULL) || 567 (bigobj->resident_page_count < obj->resident_page_count))) { 568 bigobj = obj; 569 } 570 } 571 if (tmpe->wired_count > 0) 572 nothingwired = FALSE; 573 tmpe = tmpe->next; 574 } 575 576 if (bigobj) 577 vm_pageout_object_deactivate_pages(map, bigobj, desired, 0); 578 579 /* 580 * Next, hunt around for other pages to deactivate. We actually 581 * do this search sort of wrong -- .text first is not the best idea. 582 */ 583 tmpe = map->header.next; 584 while (tmpe != &map->header) { 585 if (pmap_resident_count(vm_map_pmap(map)) <= desired) 586 break; 587 if ((tmpe->eflags & MAP_ENTRY_IS_SUB_MAP) == 0) { 588 obj = tmpe->object.vm_object; 589 if (obj) 590 vm_pageout_object_deactivate_pages(map, obj, desired, 0); 591 } 592 tmpe = tmpe->next; 593 }; 594 595 /* 596 * Remove all mappings if a process is swapped out, this will free page 597 * table pages. 598 */ 599 if (desired == 0 && nothingwired) 600 pmap_remove(vm_map_pmap(map), 601 VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS); 602 vm_map_unlock(map); 603 return; 604} 605#endif /* !defined(NO_SWAPPING) */ 606 607/* 608 * Don't try to be fancy - being fancy can lead to VOP_LOCK's and therefore 609 * to vnode deadlocks. We only do it for OBJT_DEFAULT and OBJT_SWAP objects 610 * which we know can be trivially freed. 611 */ 612void 613vm_pageout_page_free(vm_page_t m) { 614 vm_object_t object = m->object; 615 int type = object->type; 616 617 GIANT_REQUIRED; 618 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 619 vm_object_reference(object); 620 vm_page_busy(m); 621 vm_page_protect(m, VM_PROT_NONE); 622 vm_page_free(m); 623 if (type == OBJT_SWAP || type == OBJT_DEFAULT) 624 vm_object_deallocate(object); 625} 626 627/* 628 * vm_pageout_scan does the dirty work for the pageout daemon. 629 */ 630static void 631vm_pageout_scan(int pass) 632{ 633 vm_page_t m, next; 634 struct vm_page marker; 635 int save_page_shortage; 636 int save_inactive_count; 637 int page_shortage, maxscan, pcount; 638 int addl_page_shortage, addl_page_shortage_init; 639 struct proc *p, *bigproc; 640 vm_offset_t size, bigsize; 641 vm_object_t object; 642 int actcount; 643 int vnodes_skipped = 0; 644 int maxlaunder; 645 int s; 646 647 GIANT_REQUIRED; 648 /* 649 * Do whatever cleanup that the pmap code can. 650 */ 651 pmap_collect();
|
652 653 addl_page_shortage_init = vm_pageout_deficit; 654 vm_pageout_deficit = 0; 655 656 /* 657 * Calculate the number of pages we want to either free or move 658 * to the cache. 659 */ 660 page_shortage = vm_paging_target() + addl_page_shortage_init; 661 save_page_shortage = page_shortage; 662 save_inactive_count = cnt.v_inactive_count; 663 664 /* 665 * Initialize our marker 666 */ 667 bzero(&marker, sizeof(marker)); 668 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER; 669 marker.queue = PQ_INACTIVE; 670 marker.wire_count = 1; 671 672 /* 673 * Start scanning the inactive queue for pages we can move to the 674 * cache or free. The scan will stop when the target is reached or 675 * we have scanned the entire inactive queue. Note that m->act_count 676 * is not used to form decisions for the inactive queue, only for the 677 * active queue. 678 * 679 * maxlaunder limits the number of dirty pages we flush per scan. 680 * For most systems a smaller value (16 or 32) is more robust under 681 * extreme memory and disk pressure because any unnecessary writes 682 * to disk can result in extreme performance degredation. However, 683 * systems with excessive dirty pages (especially when MAP_NOSYNC is 684 * used) will die horribly with limited laundering. If the pageout 685 * daemon cannot clean enough pages in the first pass, we let it go 686 * all out in succeeding passes. 687 */ 688 if ((maxlaunder = vm_max_launder) <= 1) 689 maxlaunder = 1; 690 if (pass) 691 maxlaunder = 10000; 692rescan0: 693 addl_page_shortage = addl_page_shortage_init; 694 maxscan = cnt.v_inactive_count; 695 696 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 697 m != NULL && maxscan-- > 0 && page_shortage > 0; 698 m = next) { 699 700 cnt.v_pdpages++; 701 702 if (m->queue != PQ_INACTIVE) { 703 goto rescan0; 704 } 705 706 next = TAILQ_NEXT(m, pageq); 707 708 /* 709 * skip marker pages 710 */ 711 if (m->flags & PG_MARKER) 712 continue; 713 714 /* 715 * A held page may be undergoing I/O, so skip it. 716 */ 717 if (m->hold_count) { 718 vm_pageq_requeue(m); 719 addl_page_shortage++; 720 continue; 721 } 722 /* 723 * Don't mess with busy pages, keep in the front of the 724 * queue, most likely are being paged out. 725 */ 726 if (m->busy || (m->flags & PG_BUSY)) { 727 addl_page_shortage++; 728 continue; 729 } 730 731 /* 732 * If the object is not being used, we ignore previous 733 * references. 734 */ 735 if (m->object->ref_count == 0) { 736 vm_page_flag_clear(m, PG_REFERENCED); 737 pmap_clear_reference(m); 738 739 /* 740 * Otherwise, if the page has been referenced while in the 741 * inactive queue, we bump the "activation count" upwards, 742 * making it less likely that the page will be added back to 743 * the inactive queue prematurely again. Here we check the 744 * page tables (or emulated bits, if any), given the upper 745 * level VM system not knowing anything about existing 746 * references. 747 */ 748 } else if (((m->flags & PG_REFERENCED) == 0) && 749 (actcount = pmap_ts_referenced(m))) { 750 vm_page_activate(m); 751 m->act_count += (actcount + ACT_ADVANCE); 752 continue; 753 } 754 755 /* 756 * If the upper level VM system knows about any page 757 * references, we activate the page. We also set the 758 * "activation count" higher than normal so that we will less 759 * likely place pages back onto the inactive queue again. 760 */ 761 if ((m->flags & PG_REFERENCED) != 0) { 762 vm_page_flag_clear(m, PG_REFERENCED); 763 actcount = pmap_ts_referenced(m); 764 vm_page_activate(m); 765 m->act_count += (actcount + ACT_ADVANCE + 1); 766 continue; 767 } 768 769 /* 770 * If the upper level VM system doesn't know anything about 771 * the page being dirty, we have to check for it again. As 772 * far as the VM code knows, any partially dirty pages are 773 * fully dirty. 774 */ 775 if (m->dirty == 0) { 776 vm_page_test_dirty(m); 777 } else { 778 vm_page_dirty(m); 779 } 780 781 /* 782 * Invalid pages can be easily freed 783 */ 784 if (m->valid == 0) { 785 vm_pageout_page_free(m); 786 cnt.v_dfree++; 787 --page_shortage; 788 789 /* 790 * Clean pages can be placed onto the cache queue. This 791 * effectively frees them. 792 */ 793 } else if (m->dirty == 0) { 794 vm_page_cache(m); 795 --page_shortage; 796 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) { 797 /* 798 * Dirty pages need to be paged out, but flushing 799 * a page is extremely expensive verses freeing 800 * a clean page. Rather then artificially limiting 801 * the number of pages we can flush, we instead give 802 * dirty pages extra priority on the inactive queue 803 * by forcing them to be cycled through the queue 804 * twice before being flushed, after which the 805 * (now clean) page will cycle through once more 806 * before being freed. This significantly extends 807 * the thrash point for a heavily loaded machine. 808 */ 809 vm_page_flag_set(m, PG_WINATCFLS); 810 vm_pageq_requeue(m); 811 } else if (maxlaunder > 0) { 812 /* 813 * We always want to try to flush some dirty pages if 814 * we encounter them, to keep the system stable. 815 * Normally this number is small, but under extreme 816 * pressure where there are insufficient clean pages 817 * on the inactive queue, we may have to go all out. 818 */ 819 int swap_pageouts_ok; 820 struct vnode *vp = NULL; 821 struct mount *mp; 822 823 object = m->object; 824 825 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) { 826 swap_pageouts_ok = 1; 827 } else { 828 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts); 829 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts && 830 vm_page_count_min()); 831 832 } 833 834 /* 835 * We don't bother paging objects that are "dead". 836 * Those objects are in a "rundown" state. 837 */ 838 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { 839 vm_pageq_requeue(m); 840 continue; 841 } 842 843 /* 844 * The object is already known NOT to be dead. It 845 * is possible for the vget() to block the whole 846 * pageout daemon, but the new low-memory handling 847 * code should prevent it. 848 * 849 * The previous code skipped locked vnodes and, worse, 850 * reordered pages in the queue. This results in 851 * completely non-deterministic operation and, on a 852 * busy system, can lead to extremely non-optimal 853 * pageouts. For example, it can cause clean pages 854 * to be freed and dirty pages to be moved to the end 855 * of the queue. Since dirty pages are also moved to 856 * the end of the queue once-cleaned, this gives 857 * way too large a weighting to defering the freeing 858 * of dirty pages. 859 * 860 * We can't wait forever for the vnode lock, we might 861 * deadlock due to a vn_read() getting stuck in 862 * vm_wait while holding this vnode. We skip the 863 * vnode if we can't get it in a reasonable amount 864 * of time. 865 */ 866 if (object->type == OBJT_VNODE) { 867 vp = object->handle; 868 869 mp = NULL; 870 if (vp->v_type == VREG) 871 vn_start_write(vp, &mp, V_NOWAIT); 872 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK, curthread)) { 873 ++pageout_lock_miss; 874 vn_finished_write(mp); 875 if (object->flags & OBJ_MIGHTBEDIRTY) 876 vnodes_skipped++; 877 continue; 878 } 879 880 /* 881 * The page might have been moved to another 882 * queue during potential blocking in vget() 883 * above. The page might have been freed and 884 * reused for another vnode. The object might 885 * have been reused for another vnode. 886 */ 887 if (m->queue != PQ_INACTIVE || 888 m->object != object || 889 object->handle != vp) { 890 if (object->flags & OBJ_MIGHTBEDIRTY) 891 vnodes_skipped++; 892 vput(vp); 893 vn_finished_write(mp); 894 continue; 895 } 896 897 /* 898 * The page may have been busied during the 899 * blocking in vput(); We don't move the 900 * page back onto the end of the queue so that 901 * statistics are more correct if we don't. 902 */ 903 if (m->busy || (m->flags & PG_BUSY)) { 904 vput(vp); 905 vn_finished_write(mp); 906 continue; 907 } 908 909 /* 910 * If the page has become held it might 911 * be undergoing I/O, so skip it 912 */ 913 if (m->hold_count) { 914 vm_pageq_requeue(m); 915 if (object->flags & OBJ_MIGHTBEDIRTY) 916 vnodes_skipped++; 917 vput(vp); 918 vn_finished_write(mp); 919 continue; 920 } 921 } 922 923 /* 924 * If a page is dirty, then it is either being washed 925 * (but not yet cleaned) or it is still in the 926 * laundry. If it is still in the laundry, then we 927 * start the cleaning operation. 928 * 929 * This operation may cluster, invalidating the 'next' 930 * pointer. To prevent an inordinate number of 931 * restarts we use our marker to remember our place. 932 * 933 * decrement page_shortage on success to account for 934 * the (future) cleaned page. Otherwise we could wind 935 * up laundering or cleaning too many pages. 936 */ 937 s = splvm(); 938 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq); 939 splx(s); 940 if (vm_pageout_clean(m) != 0) { 941 --page_shortage; 942 --maxlaunder; 943 } 944 s = splvm(); 945 next = TAILQ_NEXT(&marker, pageq); 946 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq); 947 splx(s); 948 if (vp) { 949 vput(vp); 950 vn_finished_write(mp); 951 } 952 } 953 } 954 955 /* 956 * Compute the number of pages we want to try to move from the 957 * active queue to the inactive queue. 958 */ 959 page_shortage = vm_paging_target() + 960 cnt.v_inactive_target - cnt.v_inactive_count; 961 page_shortage += addl_page_shortage; 962 963 /* 964 * Scan the active queue for things we can deactivate. We nominally 965 * track the per-page activity counter and use it to locate 966 * deactivation candidates. 967 */ 968 pcount = cnt.v_active_count; 969 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 970 971 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) { 972 973 /* 974 * This is a consistency check, and should likely be a panic 975 * or warning. 976 */ 977 if (m->queue != PQ_ACTIVE) { 978 break; 979 } 980 981 next = TAILQ_NEXT(m, pageq); 982 /* 983 * Don't deactivate pages that are busy. 984 */ 985 if ((m->busy != 0) || 986 (m->flags & PG_BUSY) || 987 (m->hold_count != 0)) { 988 vm_pageq_requeue(m); 989 m = next; 990 continue; 991 } 992 993 /* 994 * The count for pagedaemon pages is done after checking the 995 * page for eligibility... 996 */ 997 cnt.v_pdpages++; 998 999 /* 1000 * Check to see "how much" the page has been used. 1001 */ 1002 actcount = 0; 1003 if (m->object->ref_count != 0) { 1004 if (m->flags & PG_REFERENCED) { 1005 actcount += 1; 1006 } 1007 actcount += pmap_ts_referenced(m); 1008 if (actcount) { 1009 m->act_count += ACT_ADVANCE + actcount; 1010 if (m->act_count > ACT_MAX) 1011 m->act_count = ACT_MAX; 1012 } 1013 } 1014 1015 /* 1016 * Since we have "tested" this bit, we need to clear it now. 1017 */ 1018 vm_page_flag_clear(m, PG_REFERENCED); 1019 1020 /* 1021 * Only if an object is currently being used, do we use the 1022 * page activation count stats. 1023 */ 1024 if (actcount && (m->object->ref_count != 0)) { 1025 vm_pageq_requeue(m); 1026 } else { 1027 m->act_count -= min(m->act_count, ACT_DECLINE); 1028 if (vm_pageout_algorithm || 1029 m->object->ref_count == 0 || 1030 m->act_count == 0) { 1031 page_shortage--; 1032 if (m->object->ref_count == 0) { 1033 vm_page_protect(m, VM_PROT_NONE); 1034 if (m->dirty == 0) 1035 vm_page_cache(m); 1036 else 1037 vm_page_deactivate(m); 1038 } else { 1039 vm_page_deactivate(m); 1040 } 1041 } else { 1042 vm_pageq_requeue(m); 1043 } 1044 } 1045 m = next; 1046 } 1047 1048 s = splvm(); 1049 1050 /* 1051 * We try to maintain some *really* free pages, this allows interrupt 1052 * code to be guaranteed space. Since both cache and free queues 1053 * are considered basically 'free', moving pages from cache to free 1054 * does not effect other calculations. 1055 */ 1056 while (cnt.v_free_count < cnt.v_free_reserved) { 1057 static int cache_rover = 0; 1058 m = vm_pageq_find(PQ_CACHE, cache_rover, FALSE); 1059 if (!m) 1060 break; 1061 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || 1062 m->busy || 1063 m->hold_count || 1064 m->wire_count) { 1065#ifdef INVARIANTS 1066 printf("Warning: busy page %p found in cache\n", m); 1067#endif 1068 vm_page_deactivate(m); 1069 continue; 1070 } 1071 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK; 1072 vm_pageout_page_free(m); 1073 cnt.v_dfree++; 1074 } 1075 splx(s); 1076 1077#if !defined(NO_SWAPPING) 1078 /* 1079 * Idle process swapout -- run once per second. 1080 */ 1081 if (vm_swap_idle_enabled) { 1082 static long lsec; 1083 if (time_second != lsec) { 1084 vm_pageout_req_swapout |= VM_SWAP_IDLE; 1085 vm_req_vmdaemon(); 1086 lsec = time_second; 1087 } 1088 } 1089#endif 1090 1091 /* 1092 * If we didn't get enough free pages, and we have skipped a vnode 1093 * in a writeable object, wakeup the sync daemon. And kick swapout 1094 * if we did not get enough free pages. 1095 */ 1096 if (vm_paging_target() > 0) { 1097 if (vnodes_skipped && vm_page_count_min()) 1098 (void) speedup_syncer(); 1099#if !defined(NO_SWAPPING) 1100 if (vm_swap_enabled && vm_page_count_target()) { 1101 vm_req_vmdaemon(); 1102 vm_pageout_req_swapout |= VM_SWAP_NORMAL; 1103 } 1104#endif 1105 } 1106 1107 /* 1108 * If we are out of swap and were not able to reach our paging 1109 * target, kill the largest process. 1110 * 1111 * We keep the process bigproc locked once we find it to keep anyone 1112 * from messing with it; however, there is a possibility of 1113 * deadlock if process B is bigproc and one of it's child processes 1114 * attempts to propagate a signal to B while we are waiting for A's 1115 * lock while walking this list. To avoid this, we don't block on 1116 * the process lock but just skip a process if it is already locked. 1117 */ 1118 if ((vm_swap_size < 64 && vm_page_count_min()) || 1119 (swap_pager_full && vm_paging_target() > 0)) { 1120#if 0 1121 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) { 1122#endif 1123 bigproc = NULL; 1124 bigsize = 0; 1125 sx_slock(&allproc_lock); 1126 LIST_FOREACH(p, &allproc, p_list) { 1127 /* 1128 * If this process is already locked, skip it. 1129 */ 1130 if (PROC_TRYLOCK(p) == 0) 1131 continue; 1132 /* 1133 * if this is a system process, skip it 1134 */ 1135 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) || 1136 ((p->p_pid < 48) && (vm_swap_size != 0))) { 1137 PROC_UNLOCK(p); 1138 continue; 1139 } 1140 /* 1141 * if the process is in a non-running type state, 1142 * don't touch it. 1143 */ 1144 mtx_lock_spin(&sched_lock); 1145 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1146 mtx_unlock_spin(&sched_lock); 1147 PROC_UNLOCK(p); 1148 continue; 1149 } 1150 mtx_unlock_spin(&sched_lock); 1151 /* 1152 * get the process size 1153 */ 1154 size = vmspace_resident_count(p->p_vmspace) + 1155 vmspace_swap_count(p->p_vmspace); 1156 /* 1157 * if the this process is bigger than the biggest one 1158 * remember it. 1159 */ 1160 if (size > bigsize) { 1161 if (bigproc != NULL) 1162 PROC_UNLOCK(bigproc); 1163 bigproc = p; 1164 bigsize = size; 1165 } else 1166 PROC_UNLOCK(p); 1167 } 1168 sx_sunlock(&allproc_lock); 1169 if (bigproc != NULL) { 1170 struct ksegrp *kg; 1171 killproc(bigproc, "out of swap space"); 1172 mtx_lock_spin(&sched_lock); 1173 FOREACH_KSEGRP_IN_PROC(bigproc, kg) { 1174 kg->kg_estcpu = 0; 1175 kg->kg_nice = PRIO_MIN; /* XXXKSE ??? */ 1176 resetpriority(kg); 1177 } 1178 mtx_unlock_spin(&sched_lock); 1179 PROC_UNLOCK(bigproc); 1180 wakeup(&cnt.v_free_count); 1181 } 1182 } 1183} 1184 1185/* 1186 * This routine tries to maintain the pseudo LRU active queue, 1187 * so that during long periods of time where there is no paging, 1188 * that some statistic accumulation still occurs. This code 1189 * helps the situation where paging just starts to occur. 1190 */ 1191static void 1192vm_pageout_page_stats() 1193{ 1194 vm_page_t m,next; 1195 int pcount,tpcount; /* Number of pages to check */ 1196 static int fullintervalcount = 0; 1197 int page_shortage; 1198 int s0; 1199 1200 page_shortage = 1201 (cnt.v_inactive_target + cnt.v_cache_max + cnt.v_free_min) - 1202 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); 1203 1204 if (page_shortage <= 0) 1205 return; 1206 1207 s0 = splvm(); 1208 1209 pcount = cnt.v_active_count; 1210 fullintervalcount += vm_pageout_stats_interval; 1211 if (fullintervalcount < vm_pageout_full_stats_interval) { 1212 tpcount = (vm_pageout_stats_max * cnt.v_active_count) / cnt.v_page_count; 1213 if (pcount > tpcount) 1214 pcount = tpcount; 1215 } else { 1216 fullintervalcount = 0; 1217 } 1218 1219 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1220 while ((m != NULL) && (pcount-- > 0)) { 1221 int actcount; 1222 1223 if (m->queue != PQ_ACTIVE) { 1224 break; 1225 } 1226 1227 next = TAILQ_NEXT(m, pageq); 1228 /* 1229 * Don't deactivate pages that are busy. 1230 */ 1231 if ((m->busy != 0) || 1232 (m->flags & PG_BUSY) || 1233 (m->hold_count != 0)) { 1234 vm_pageq_requeue(m); 1235 m = next; 1236 continue; 1237 } 1238 1239 actcount = 0; 1240 if (m->flags & PG_REFERENCED) { 1241 vm_page_flag_clear(m, PG_REFERENCED); 1242 actcount += 1; 1243 } 1244 1245 actcount += pmap_ts_referenced(m); 1246 if (actcount) { 1247 m->act_count += ACT_ADVANCE + actcount; 1248 if (m->act_count > ACT_MAX) 1249 m->act_count = ACT_MAX; 1250 vm_pageq_requeue(m); 1251 } else { 1252 if (m->act_count == 0) { 1253 /* 1254 * We turn off page access, so that we have 1255 * more accurate RSS stats. We don't do this 1256 * in the normal page deactivation when the 1257 * system is loaded VM wise, because the 1258 * cost of the large number of page protect 1259 * operations would be higher than the value 1260 * of doing the operation. 1261 */ 1262 vm_page_protect(m, VM_PROT_NONE); 1263 vm_page_deactivate(m); 1264 } else { 1265 m->act_count -= min(m->act_count, ACT_DECLINE); 1266 vm_pageq_requeue(m); 1267 } 1268 } 1269 1270 m = next; 1271 } 1272 splx(s0); 1273} 1274 1275static int 1276vm_pageout_free_page_calc(count) 1277vm_size_t count; 1278{ 1279 if (count < cnt.v_page_count) 1280 return 0; 1281 /* 1282 * free_reserved needs to include enough for the largest swap pager 1283 * structures plus enough for any pv_entry structs when paging. 1284 */ 1285 if (cnt.v_page_count > 1024) 1286 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; 1287 else 1288 cnt.v_free_min = 4; 1289 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE + 1290 cnt.v_interrupt_free_min; 1291 cnt.v_free_reserved = vm_pageout_page_count + 1292 cnt.v_pageout_free_min + (count / 768) + PQ_L2_SIZE; 1293 cnt.v_free_severe = cnt.v_free_min / 2; 1294 cnt.v_free_min += cnt.v_free_reserved; 1295 cnt.v_free_severe += cnt.v_free_reserved; 1296 return 1; 1297} 1298 1299/* 1300 * vm_pageout is the high level pageout daemon. 1301 */ 1302static void 1303vm_pageout() 1304{ 1305 int pass; 1306 1307 mtx_lock(&Giant); 1308 1309 /* 1310 * Initialize some paging parameters. 1311 */ 1312 cnt.v_interrupt_free_min = 2; 1313 if (cnt.v_page_count < 2000) 1314 vm_pageout_page_count = 8; 1315 1316 vm_pageout_free_page_calc(cnt.v_page_count); 1317 /* 1318 * v_free_target and v_cache_min control pageout hysteresis. Note 1319 * that these are more a measure of the VM cache queue hysteresis 1320 * then the VM free queue. Specifically, v_free_target is the 1321 * high water mark (free+cache pages). 1322 * 1323 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the 1324 * low water mark, while v_free_min is the stop. v_cache_min must 1325 * be big enough to handle memory needs while the pageout daemon 1326 * is signalled and run to free more pages. 1327 */ 1328 if (cnt.v_free_count > 6144) 1329 cnt.v_free_target = 4 * cnt.v_free_min + cnt.v_free_reserved; 1330 else 1331 cnt.v_free_target = 2 * cnt.v_free_min + cnt.v_free_reserved; 1332 1333 if (cnt.v_free_count > 2048) { 1334 cnt.v_cache_min = cnt.v_free_target; 1335 cnt.v_cache_max = 2 * cnt.v_cache_min; 1336 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2; 1337 } else { 1338 cnt.v_cache_min = 0; 1339 cnt.v_cache_max = 0; 1340 cnt.v_inactive_target = cnt.v_free_count / 4; 1341 } 1342 if (cnt.v_inactive_target > cnt.v_free_count / 3) 1343 cnt.v_inactive_target = cnt.v_free_count / 3; 1344 1345 /* XXX does not really belong here */ 1346 if (vm_page_max_wired == 0) 1347 vm_page_max_wired = cnt.v_free_count / 3; 1348 1349 if (vm_pageout_stats_max == 0) 1350 vm_pageout_stats_max = cnt.v_free_target; 1351 1352 /* 1353 * Set interval in seconds for stats scan. 1354 */ 1355 if (vm_pageout_stats_interval == 0) 1356 vm_pageout_stats_interval = 5; 1357 if (vm_pageout_full_stats_interval == 0) 1358 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4; 1359 1360 /* 1361 * Set maximum free per pass 1362 */ 1363 if (vm_pageout_stats_free_max == 0) 1364 vm_pageout_stats_free_max = 5; 1365 1366 swap_pager_swap_init(); 1367 pass = 0; 1368 /* 1369 * The pageout daemon is never done, so loop forever. 1370 */ 1371 while (TRUE) { 1372 int error; 1373 int s = splvm(); 1374 1375 /* 1376 * If we have enough free memory, wakeup waiters. Do 1377 * not clear vm_pages_needed until we reach our target, 1378 * otherwise we may be woken up over and over again and 1379 * waste a lot of cpu. 1380 */ 1381 if (vm_pages_needed && !vm_page_count_min()) { 1382 if (vm_paging_needed() <= 0) 1383 vm_pages_needed = 0; 1384 wakeup(&cnt.v_free_count); 1385 } 1386 if (vm_pages_needed) { 1387 /* 1388 * Still not done, take a second pass without waiting 1389 * (unlimited dirty cleaning), otherwise sleep a bit 1390 * and try again. 1391 */ 1392 ++pass; 1393 if (pass > 1) 1394 tsleep(&vm_pages_needed, PVM, 1395 "psleep", hz/2); 1396 } else { 1397 /* 1398 * Good enough, sleep & handle stats. Prime the pass 1399 * for the next run. 1400 */ 1401 if (pass > 1) 1402 pass = 1; 1403 else 1404 pass = 0; 1405 error = tsleep(&vm_pages_needed, PVM, 1406 "psleep", vm_pageout_stats_interval * hz); 1407 if (error && !vm_pages_needed) { 1408 splx(s); 1409 pass = 0; 1410 vm_pageout_page_stats(); 1411 continue; 1412 } 1413 } 1414 1415 if (vm_pages_needed) 1416 cnt.v_pdwakeups++; 1417 splx(s); 1418 vm_pageout_scan(pass); 1419 vm_pageout_deficit = 0; 1420 } 1421} 1422 1423void 1424pagedaemon_wakeup() 1425{ 1426 if (!vm_pages_needed && curthread->td_proc != pageproc) { 1427 vm_pages_needed++; 1428 wakeup(&vm_pages_needed); 1429 } 1430} 1431 1432#if !defined(NO_SWAPPING) 1433static void 1434vm_req_vmdaemon() 1435{ 1436 static int lastrun = 0; 1437 1438 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) { 1439 wakeup(&vm_daemon_needed); 1440 lastrun = ticks; 1441 } 1442} 1443 1444static void 1445vm_daemon() 1446{ 1447 struct proc *p; 1448 1449 mtx_lock(&Giant); 1450 while (TRUE) { 1451 tsleep(&vm_daemon_needed, PPAUSE, "psleep", 0); 1452 if (vm_pageout_req_swapout) { 1453 swapout_procs(vm_pageout_req_swapout); 1454 vm_pageout_req_swapout = 0; 1455 } 1456 /* 1457 * scan the processes for exceeding their rlimits or if 1458 * process is swapped out -- deactivate pages 1459 */ 1460 sx_slock(&allproc_lock); 1461 LIST_FOREACH(p, &allproc, p_list) { 1462 vm_pindex_t limit, size; 1463 1464 /* 1465 * if this is a system process or if we have already 1466 * looked at this process, skip it. 1467 */ 1468 if (p->p_flag & (P_SYSTEM | P_WEXIT)) { 1469 continue; 1470 } 1471 /* 1472 * if the process is in a non-running type state, 1473 * don't touch it. 1474 */ 1475 mtx_lock_spin(&sched_lock); 1476 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1477 mtx_unlock_spin(&sched_lock); 1478 continue; 1479 } 1480 /* 1481 * get a limit 1482 */ 1483 limit = OFF_TO_IDX( 1484 qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, 1485 p->p_rlimit[RLIMIT_RSS].rlim_max)); 1486 1487 /* 1488 * let processes that are swapped out really be 1489 * swapped out set the limit to nothing (will force a 1490 * swap-out.) 1491 */ 1492 if ((p->p_sflag & PS_INMEM) == 0) 1493 limit = 0; /* XXX */ 1494 mtx_unlock_spin(&sched_lock); 1495 1496 size = vmspace_resident_count(p->p_vmspace); 1497 if (limit >= 0 && size >= limit) { 1498 vm_pageout_map_deactivate_pages( 1499 &p->p_vmspace->vm_map, limit); 1500 } 1501 } 1502 sx_sunlock(&allproc_lock); 1503 } 1504} 1505#endif /* !defined(NO_SWAPPING) */
| 653 654 addl_page_shortage_init = vm_pageout_deficit; 655 vm_pageout_deficit = 0; 656 657 /* 658 * Calculate the number of pages we want to either free or move 659 * to the cache. 660 */ 661 page_shortage = vm_paging_target() + addl_page_shortage_init; 662 save_page_shortage = page_shortage; 663 save_inactive_count = cnt.v_inactive_count; 664 665 /* 666 * Initialize our marker 667 */ 668 bzero(&marker, sizeof(marker)); 669 marker.flags = PG_BUSY | PG_FICTITIOUS | PG_MARKER; 670 marker.queue = PQ_INACTIVE; 671 marker.wire_count = 1; 672 673 /* 674 * Start scanning the inactive queue for pages we can move to the 675 * cache or free. The scan will stop when the target is reached or 676 * we have scanned the entire inactive queue. Note that m->act_count 677 * is not used to form decisions for the inactive queue, only for the 678 * active queue. 679 * 680 * maxlaunder limits the number of dirty pages we flush per scan. 681 * For most systems a smaller value (16 or 32) is more robust under 682 * extreme memory and disk pressure because any unnecessary writes 683 * to disk can result in extreme performance degredation. However, 684 * systems with excessive dirty pages (especially when MAP_NOSYNC is 685 * used) will die horribly with limited laundering. If the pageout 686 * daemon cannot clean enough pages in the first pass, we let it go 687 * all out in succeeding passes. 688 */ 689 if ((maxlaunder = vm_max_launder) <= 1) 690 maxlaunder = 1; 691 if (pass) 692 maxlaunder = 10000; 693rescan0: 694 addl_page_shortage = addl_page_shortage_init; 695 maxscan = cnt.v_inactive_count; 696 697 for (m = TAILQ_FIRST(&vm_page_queues[PQ_INACTIVE].pl); 698 m != NULL && maxscan-- > 0 && page_shortage > 0; 699 m = next) { 700 701 cnt.v_pdpages++; 702 703 if (m->queue != PQ_INACTIVE) { 704 goto rescan0; 705 } 706 707 next = TAILQ_NEXT(m, pageq); 708 709 /* 710 * skip marker pages 711 */ 712 if (m->flags & PG_MARKER) 713 continue; 714 715 /* 716 * A held page may be undergoing I/O, so skip it. 717 */ 718 if (m->hold_count) { 719 vm_pageq_requeue(m); 720 addl_page_shortage++; 721 continue; 722 } 723 /* 724 * Don't mess with busy pages, keep in the front of the 725 * queue, most likely are being paged out. 726 */ 727 if (m->busy || (m->flags & PG_BUSY)) { 728 addl_page_shortage++; 729 continue; 730 } 731 732 /* 733 * If the object is not being used, we ignore previous 734 * references. 735 */ 736 if (m->object->ref_count == 0) { 737 vm_page_flag_clear(m, PG_REFERENCED); 738 pmap_clear_reference(m); 739 740 /* 741 * Otherwise, if the page has been referenced while in the 742 * inactive queue, we bump the "activation count" upwards, 743 * making it less likely that the page will be added back to 744 * the inactive queue prematurely again. Here we check the 745 * page tables (or emulated bits, if any), given the upper 746 * level VM system not knowing anything about existing 747 * references. 748 */ 749 } else if (((m->flags & PG_REFERENCED) == 0) && 750 (actcount = pmap_ts_referenced(m))) { 751 vm_page_activate(m); 752 m->act_count += (actcount + ACT_ADVANCE); 753 continue; 754 } 755 756 /* 757 * If the upper level VM system knows about any page 758 * references, we activate the page. We also set the 759 * "activation count" higher than normal so that we will less 760 * likely place pages back onto the inactive queue again. 761 */ 762 if ((m->flags & PG_REFERENCED) != 0) { 763 vm_page_flag_clear(m, PG_REFERENCED); 764 actcount = pmap_ts_referenced(m); 765 vm_page_activate(m); 766 m->act_count += (actcount + ACT_ADVANCE + 1); 767 continue; 768 } 769 770 /* 771 * If the upper level VM system doesn't know anything about 772 * the page being dirty, we have to check for it again. As 773 * far as the VM code knows, any partially dirty pages are 774 * fully dirty. 775 */ 776 if (m->dirty == 0) { 777 vm_page_test_dirty(m); 778 } else { 779 vm_page_dirty(m); 780 } 781 782 /* 783 * Invalid pages can be easily freed 784 */ 785 if (m->valid == 0) { 786 vm_pageout_page_free(m); 787 cnt.v_dfree++; 788 --page_shortage; 789 790 /* 791 * Clean pages can be placed onto the cache queue. This 792 * effectively frees them. 793 */ 794 } else if (m->dirty == 0) { 795 vm_page_cache(m); 796 --page_shortage; 797 } else if ((m->flags & PG_WINATCFLS) == 0 && pass == 0) { 798 /* 799 * Dirty pages need to be paged out, but flushing 800 * a page is extremely expensive verses freeing 801 * a clean page. Rather then artificially limiting 802 * the number of pages we can flush, we instead give 803 * dirty pages extra priority on the inactive queue 804 * by forcing them to be cycled through the queue 805 * twice before being flushed, after which the 806 * (now clean) page will cycle through once more 807 * before being freed. This significantly extends 808 * the thrash point for a heavily loaded machine. 809 */ 810 vm_page_flag_set(m, PG_WINATCFLS); 811 vm_pageq_requeue(m); 812 } else if (maxlaunder > 0) { 813 /* 814 * We always want to try to flush some dirty pages if 815 * we encounter them, to keep the system stable. 816 * Normally this number is small, but under extreme 817 * pressure where there are insufficient clean pages 818 * on the inactive queue, we may have to go all out. 819 */ 820 int swap_pageouts_ok; 821 struct vnode *vp = NULL; 822 struct mount *mp; 823 824 object = m->object; 825 826 if ((object->type != OBJT_SWAP) && (object->type != OBJT_DEFAULT)) { 827 swap_pageouts_ok = 1; 828 } else { 829 swap_pageouts_ok = !(defer_swap_pageouts || disable_swap_pageouts); 830 swap_pageouts_ok |= (!disable_swap_pageouts && defer_swap_pageouts && 831 vm_page_count_min()); 832 833 } 834 835 /* 836 * We don't bother paging objects that are "dead". 837 * Those objects are in a "rundown" state. 838 */ 839 if (!swap_pageouts_ok || (object->flags & OBJ_DEAD)) { 840 vm_pageq_requeue(m); 841 continue; 842 } 843 844 /* 845 * The object is already known NOT to be dead. It 846 * is possible for the vget() to block the whole 847 * pageout daemon, but the new low-memory handling 848 * code should prevent it. 849 * 850 * The previous code skipped locked vnodes and, worse, 851 * reordered pages in the queue. This results in 852 * completely non-deterministic operation and, on a 853 * busy system, can lead to extremely non-optimal 854 * pageouts. For example, it can cause clean pages 855 * to be freed and dirty pages to be moved to the end 856 * of the queue. Since dirty pages are also moved to 857 * the end of the queue once-cleaned, this gives 858 * way too large a weighting to defering the freeing 859 * of dirty pages. 860 * 861 * We can't wait forever for the vnode lock, we might 862 * deadlock due to a vn_read() getting stuck in 863 * vm_wait while holding this vnode. We skip the 864 * vnode if we can't get it in a reasonable amount 865 * of time. 866 */ 867 if (object->type == OBJT_VNODE) { 868 vp = object->handle; 869 870 mp = NULL; 871 if (vp->v_type == VREG) 872 vn_start_write(vp, &mp, V_NOWAIT); 873 if (vget(vp, LK_EXCLUSIVE|LK_NOOBJ|LK_TIMELOCK, curthread)) { 874 ++pageout_lock_miss; 875 vn_finished_write(mp); 876 if (object->flags & OBJ_MIGHTBEDIRTY) 877 vnodes_skipped++; 878 continue; 879 } 880 881 /* 882 * The page might have been moved to another 883 * queue during potential blocking in vget() 884 * above. The page might have been freed and 885 * reused for another vnode. The object might 886 * have been reused for another vnode. 887 */ 888 if (m->queue != PQ_INACTIVE || 889 m->object != object || 890 object->handle != vp) { 891 if (object->flags & OBJ_MIGHTBEDIRTY) 892 vnodes_skipped++; 893 vput(vp); 894 vn_finished_write(mp); 895 continue; 896 } 897 898 /* 899 * The page may have been busied during the 900 * blocking in vput(); We don't move the 901 * page back onto the end of the queue so that 902 * statistics are more correct if we don't. 903 */ 904 if (m->busy || (m->flags & PG_BUSY)) { 905 vput(vp); 906 vn_finished_write(mp); 907 continue; 908 } 909 910 /* 911 * If the page has become held it might 912 * be undergoing I/O, so skip it 913 */ 914 if (m->hold_count) { 915 vm_pageq_requeue(m); 916 if (object->flags & OBJ_MIGHTBEDIRTY) 917 vnodes_skipped++; 918 vput(vp); 919 vn_finished_write(mp); 920 continue; 921 } 922 } 923 924 /* 925 * If a page is dirty, then it is either being washed 926 * (but not yet cleaned) or it is still in the 927 * laundry. If it is still in the laundry, then we 928 * start the cleaning operation. 929 * 930 * This operation may cluster, invalidating the 'next' 931 * pointer. To prevent an inordinate number of 932 * restarts we use our marker to remember our place. 933 * 934 * decrement page_shortage on success to account for 935 * the (future) cleaned page. Otherwise we could wind 936 * up laundering or cleaning too many pages. 937 */ 938 s = splvm(); 939 TAILQ_INSERT_AFTER(&vm_page_queues[PQ_INACTIVE].pl, m, &marker, pageq); 940 splx(s); 941 if (vm_pageout_clean(m) != 0) { 942 --page_shortage; 943 --maxlaunder; 944 } 945 s = splvm(); 946 next = TAILQ_NEXT(&marker, pageq); 947 TAILQ_REMOVE(&vm_page_queues[PQ_INACTIVE].pl, &marker, pageq); 948 splx(s); 949 if (vp) { 950 vput(vp); 951 vn_finished_write(mp); 952 } 953 } 954 } 955 956 /* 957 * Compute the number of pages we want to try to move from the 958 * active queue to the inactive queue. 959 */ 960 page_shortage = vm_paging_target() + 961 cnt.v_inactive_target - cnt.v_inactive_count; 962 page_shortage += addl_page_shortage; 963 964 /* 965 * Scan the active queue for things we can deactivate. We nominally 966 * track the per-page activity counter and use it to locate 967 * deactivation candidates. 968 */ 969 pcount = cnt.v_active_count; 970 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 971 972 while ((m != NULL) && (pcount-- > 0) && (page_shortage > 0)) { 973 974 /* 975 * This is a consistency check, and should likely be a panic 976 * or warning. 977 */ 978 if (m->queue != PQ_ACTIVE) { 979 break; 980 } 981 982 next = TAILQ_NEXT(m, pageq); 983 /* 984 * Don't deactivate pages that are busy. 985 */ 986 if ((m->busy != 0) || 987 (m->flags & PG_BUSY) || 988 (m->hold_count != 0)) { 989 vm_pageq_requeue(m); 990 m = next; 991 continue; 992 } 993 994 /* 995 * The count for pagedaemon pages is done after checking the 996 * page for eligibility... 997 */ 998 cnt.v_pdpages++; 999 1000 /* 1001 * Check to see "how much" the page has been used. 1002 */ 1003 actcount = 0; 1004 if (m->object->ref_count != 0) { 1005 if (m->flags & PG_REFERENCED) { 1006 actcount += 1; 1007 } 1008 actcount += pmap_ts_referenced(m); 1009 if (actcount) { 1010 m->act_count += ACT_ADVANCE + actcount; 1011 if (m->act_count > ACT_MAX) 1012 m->act_count = ACT_MAX; 1013 } 1014 } 1015 1016 /* 1017 * Since we have "tested" this bit, we need to clear it now. 1018 */ 1019 vm_page_flag_clear(m, PG_REFERENCED); 1020 1021 /* 1022 * Only if an object is currently being used, do we use the 1023 * page activation count stats. 1024 */ 1025 if (actcount && (m->object->ref_count != 0)) { 1026 vm_pageq_requeue(m); 1027 } else { 1028 m->act_count -= min(m->act_count, ACT_DECLINE); 1029 if (vm_pageout_algorithm || 1030 m->object->ref_count == 0 || 1031 m->act_count == 0) { 1032 page_shortage--; 1033 if (m->object->ref_count == 0) { 1034 vm_page_protect(m, VM_PROT_NONE); 1035 if (m->dirty == 0) 1036 vm_page_cache(m); 1037 else 1038 vm_page_deactivate(m); 1039 } else { 1040 vm_page_deactivate(m); 1041 } 1042 } else { 1043 vm_pageq_requeue(m); 1044 } 1045 } 1046 m = next; 1047 } 1048 1049 s = splvm(); 1050 1051 /* 1052 * We try to maintain some *really* free pages, this allows interrupt 1053 * code to be guaranteed space. Since both cache and free queues 1054 * are considered basically 'free', moving pages from cache to free 1055 * does not effect other calculations. 1056 */ 1057 while (cnt.v_free_count < cnt.v_free_reserved) { 1058 static int cache_rover = 0; 1059 m = vm_pageq_find(PQ_CACHE, cache_rover, FALSE); 1060 if (!m) 1061 break; 1062 if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || 1063 m->busy || 1064 m->hold_count || 1065 m->wire_count) { 1066#ifdef INVARIANTS 1067 printf("Warning: busy page %p found in cache\n", m); 1068#endif 1069 vm_page_deactivate(m); 1070 continue; 1071 } 1072 cache_rover = (cache_rover + PQ_PRIME2) & PQ_L2_MASK; 1073 vm_pageout_page_free(m); 1074 cnt.v_dfree++; 1075 } 1076 splx(s); 1077 1078#if !defined(NO_SWAPPING) 1079 /* 1080 * Idle process swapout -- run once per second. 1081 */ 1082 if (vm_swap_idle_enabled) { 1083 static long lsec; 1084 if (time_second != lsec) { 1085 vm_pageout_req_swapout |= VM_SWAP_IDLE; 1086 vm_req_vmdaemon(); 1087 lsec = time_second; 1088 } 1089 } 1090#endif 1091 1092 /* 1093 * If we didn't get enough free pages, and we have skipped a vnode 1094 * in a writeable object, wakeup the sync daemon. And kick swapout 1095 * if we did not get enough free pages. 1096 */ 1097 if (vm_paging_target() > 0) { 1098 if (vnodes_skipped && vm_page_count_min()) 1099 (void) speedup_syncer(); 1100#if !defined(NO_SWAPPING) 1101 if (vm_swap_enabled && vm_page_count_target()) { 1102 vm_req_vmdaemon(); 1103 vm_pageout_req_swapout |= VM_SWAP_NORMAL; 1104 } 1105#endif 1106 } 1107 1108 /* 1109 * If we are out of swap and were not able to reach our paging 1110 * target, kill the largest process. 1111 * 1112 * We keep the process bigproc locked once we find it to keep anyone 1113 * from messing with it; however, there is a possibility of 1114 * deadlock if process B is bigproc and one of it's child processes 1115 * attempts to propagate a signal to B while we are waiting for A's 1116 * lock while walking this list. To avoid this, we don't block on 1117 * the process lock but just skip a process if it is already locked. 1118 */ 1119 if ((vm_swap_size < 64 && vm_page_count_min()) || 1120 (swap_pager_full && vm_paging_target() > 0)) { 1121#if 0 1122 if ((vm_swap_size < 64 || swap_pager_full) && vm_page_count_min()) { 1123#endif 1124 bigproc = NULL; 1125 bigsize = 0; 1126 sx_slock(&allproc_lock); 1127 LIST_FOREACH(p, &allproc, p_list) { 1128 /* 1129 * If this process is already locked, skip it. 1130 */ 1131 if (PROC_TRYLOCK(p) == 0) 1132 continue; 1133 /* 1134 * if this is a system process, skip it 1135 */ 1136 if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) || 1137 ((p->p_pid < 48) && (vm_swap_size != 0))) { 1138 PROC_UNLOCK(p); 1139 continue; 1140 } 1141 /* 1142 * if the process is in a non-running type state, 1143 * don't touch it. 1144 */ 1145 mtx_lock_spin(&sched_lock); 1146 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1147 mtx_unlock_spin(&sched_lock); 1148 PROC_UNLOCK(p); 1149 continue; 1150 } 1151 mtx_unlock_spin(&sched_lock); 1152 /* 1153 * get the process size 1154 */ 1155 size = vmspace_resident_count(p->p_vmspace) + 1156 vmspace_swap_count(p->p_vmspace); 1157 /* 1158 * if the this process is bigger than the biggest one 1159 * remember it. 1160 */ 1161 if (size > bigsize) { 1162 if (bigproc != NULL) 1163 PROC_UNLOCK(bigproc); 1164 bigproc = p; 1165 bigsize = size; 1166 } else 1167 PROC_UNLOCK(p); 1168 } 1169 sx_sunlock(&allproc_lock); 1170 if (bigproc != NULL) { 1171 struct ksegrp *kg; 1172 killproc(bigproc, "out of swap space"); 1173 mtx_lock_spin(&sched_lock); 1174 FOREACH_KSEGRP_IN_PROC(bigproc, kg) { 1175 kg->kg_estcpu = 0; 1176 kg->kg_nice = PRIO_MIN; /* XXXKSE ??? */ 1177 resetpriority(kg); 1178 } 1179 mtx_unlock_spin(&sched_lock); 1180 PROC_UNLOCK(bigproc); 1181 wakeup(&cnt.v_free_count); 1182 } 1183 } 1184} 1185 1186/* 1187 * This routine tries to maintain the pseudo LRU active queue, 1188 * so that during long periods of time where there is no paging, 1189 * that some statistic accumulation still occurs. This code 1190 * helps the situation where paging just starts to occur. 1191 */ 1192static void 1193vm_pageout_page_stats() 1194{ 1195 vm_page_t m,next; 1196 int pcount,tpcount; /* Number of pages to check */ 1197 static int fullintervalcount = 0; 1198 int page_shortage; 1199 int s0; 1200 1201 page_shortage = 1202 (cnt.v_inactive_target + cnt.v_cache_max + cnt.v_free_min) - 1203 (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); 1204 1205 if (page_shortage <= 0) 1206 return; 1207 1208 s0 = splvm(); 1209 1210 pcount = cnt.v_active_count; 1211 fullintervalcount += vm_pageout_stats_interval; 1212 if (fullintervalcount < vm_pageout_full_stats_interval) { 1213 tpcount = (vm_pageout_stats_max * cnt.v_active_count) / cnt.v_page_count; 1214 if (pcount > tpcount) 1215 pcount = tpcount; 1216 } else { 1217 fullintervalcount = 0; 1218 } 1219 1220 m = TAILQ_FIRST(&vm_page_queues[PQ_ACTIVE].pl); 1221 while ((m != NULL) && (pcount-- > 0)) { 1222 int actcount; 1223 1224 if (m->queue != PQ_ACTIVE) { 1225 break; 1226 } 1227 1228 next = TAILQ_NEXT(m, pageq); 1229 /* 1230 * Don't deactivate pages that are busy. 1231 */ 1232 if ((m->busy != 0) || 1233 (m->flags & PG_BUSY) || 1234 (m->hold_count != 0)) { 1235 vm_pageq_requeue(m); 1236 m = next; 1237 continue; 1238 } 1239 1240 actcount = 0; 1241 if (m->flags & PG_REFERENCED) { 1242 vm_page_flag_clear(m, PG_REFERENCED); 1243 actcount += 1; 1244 } 1245 1246 actcount += pmap_ts_referenced(m); 1247 if (actcount) { 1248 m->act_count += ACT_ADVANCE + actcount; 1249 if (m->act_count > ACT_MAX) 1250 m->act_count = ACT_MAX; 1251 vm_pageq_requeue(m); 1252 } else { 1253 if (m->act_count == 0) { 1254 /* 1255 * We turn off page access, so that we have 1256 * more accurate RSS stats. We don't do this 1257 * in the normal page deactivation when the 1258 * system is loaded VM wise, because the 1259 * cost of the large number of page protect 1260 * operations would be higher than the value 1261 * of doing the operation. 1262 */ 1263 vm_page_protect(m, VM_PROT_NONE); 1264 vm_page_deactivate(m); 1265 } else { 1266 m->act_count -= min(m->act_count, ACT_DECLINE); 1267 vm_pageq_requeue(m); 1268 } 1269 } 1270 1271 m = next; 1272 } 1273 splx(s0); 1274} 1275 1276static int 1277vm_pageout_free_page_calc(count) 1278vm_size_t count; 1279{ 1280 if (count < cnt.v_page_count) 1281 return 0; 1282 /* 1283 * free_reserved needs to include enough for the largest swap pager 1284 * structures plus enough for any pv_entry structs when paging. 1285 */ 1286 if (cnt.v_page_count > 1024) 1287 cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; 1288 else 1289 cnt.v_free_min = 4; 1290 cnt.v_pageout_free_min = (2*MAXBSIZE)/PAGE_SIZE + 1291 cnt.v_interrupt_free_min; 1292 cnt.v_free_reserved = vm_pageout_page_count + 1293 cnt.v_pageout_free_min + (count / 768) + PQ_L2_SIZE; 1294 cnt.v_free_severe = cnt.v_free_min / 2; 1295 cnt.v_free_min += cnt.v_free_reserved; 1296 cnt.v_free_severe += cnt.v_free_reserved; 1297 return 1; 1298} 1299 1300/* 1301 * vm_pageout is the high level pageout daemon. 1302 */ 1303static void 1304vm_pageout() 1305{ 1306 int pass; 1307 1308 mtx_lock(&Giant); 1309 1310 /* 1311 * Initialize some paging parameters. 1312 */ 1313 cnt.v_interrupt_free_min = 2; 1314 if (cnt.v_page_count < 2000) 1315 vm_pageout_page_count = 8; 1316 1317 vm_pageout_free_page_calc(cnt.v_page_count); 1318 /* 1319 * v_free_target and v_cache_min control pageout hysteresis. Note 1320 * that these are more a measure of the VM cache queue hysteresis 1321 * then the VM free queue. Specifically, v_free_target is the 1322 * high water mark (free+cache pages). 1323 * 1324 * v_free_reserved + v_cache_min (mostly means v_cache_min) is the 1325 * low water mark, while v_free_min is the stop. v_cache_min must 1326 * be big enough to handle memory needs while the pageout daemon 1327 * is signalled and run to free more pages. 1328 */ 1329 if (cnt.v_free_count > 6144) 1330 cnt.v_free_target = 4 * cnt.v_free_min + cnt.v_free_reserved; 1331 else 1332 cnt.v_free_target = 2 * cnt.v_free_min + cnt.v_free_reserved; 1333 1334 if (cnt.v_free_count > 2048) { 1335 cnt.v_cache_min = cnt.v_free_target; 1336 cnt.v_cache_max = 2 * cnt.v_cache_min; 1337 cnt.v_inactive_target = (3 * cnt.v_free_target) / 2; 1338 } else { 1339 cnt.v_cache_min = 0; 1340 cnt.v_cache_max = 0; 1341 cnt.v_inactive_target = cnt.v_free_count / 4; 1342 } 1343 if (cnt.v_inactive_target > cnt.v_free_count / 3) 1344 cnt.v_inactive_target = cnt.v_free_count / 3; 1345 1346 /* XXX does not really belong here */ 1347 if (vm_page_max_wired == 0) 1348 vm_page_max_wired = cnt.v_free_count / 3; 1349 1350 if (vm_pageout_stats_max == 0) 1351 vm_pageout_stats_max = cnt.v_free_target; 1352 1353 /* 1354 * Set interval in seconds for stats scan. 1355 */ 1356 if (vm_pageout_stats_interval == 0) 1357 vm_pageout_stats_interval = 5; 1358 if (vm_pageout_full_stats_interval == 0) 1359 vm_pageout_full_stats_interval = vm_pageout_stats_interval * 4; 1360 1361 /* 1362 * Set maximum free per pass 1363 */ 1364 if (vm_pageout_stats_free_max == 0) 1365 vm_pageout_stats_free_max = 5; 1366 1367 swap_pager_swap_init(); 1368 pass = 0; 1369 /* 1370 * The pageout daemon is never done, so loop forever. 1371 */ 1372 while (TRUE) { 1373 int error; 1374 int s = splvm(); 1375 1376 /* 1377 * If we have enough free memory, wakeup waiters. Do 1378 * not clear vm_pages_needed until we reach our target, 1379 * otherwise we may be woken up over and over again and 1380 * waste a lot of cpu. 1381 */ 1382 if (vm_pages_needed && !vm_page_count_min()) { 1383 if (vm_paging_needed() <= 0) 1384 vm_pages_needed = 0; 1385 wakeup(&cnt.v_free_count); 1386 } 1387 if (vm_pages_needed) { 1388 /* 1389 * Still not done, take a second pass without waiting 1390 * (unlimited dirty cleaning), otherwise sleep a bit 1391 * and try again. 1392 */ 1393 ++pass; 1394 if (pass > 1) 1395 tsleep(&vm_pages_needed, PVM, 1396 "psleep", hz/2); 1397 } else { 1398 /* 1399 * Good enough, sleep & handle stats. Prime the pass 1400 * for the next run. 1401 */ 1402 if (pass > 1) 1403 pass = 1; 1404 else 1405 pass = 0; 1406 error = tsleep(&vm_pages_needed, PVM, 1407 "psleep", vm_pageout_stats_interval * hz); 1408 if (error && !vm_pages_needed) { 1409 splx(s); 1410 pass = 0; 1411 vm_pageout_page_stats(); 1412 continue; 1413 } 1414 } 1415 1416 if (vm_pages_needed) 1417 cnt.v_pdwakeups++; 1418 splx(s); 1419 vm_pageout_scan(pass); 1420 vm_pageout_deficit = 0; 1421 } 1422} 1423 1424void 1425pagedaemon_wakeup() 1426{ 1427 if (!vm_pages_needed && curthread->td_proc != pageproc) { 1428 vm_pages_needed++; 1429 wakeup(&vm_pages_needed); 1430 } 1431} 1432 1433#if !defined(NO_SWAPPING) 1434static void 1435vm_req_vmdaemon() 1436{ 1437 static int lastrun = 0; 1438 1439 if ((ticks > (lastrun + hz)) || (ticks < lastrun)) { 1440 wakeup(&vm_daemon_needed); 1441 lastrun = ticks; 1442 } 1443} 1444 1445static void 1446vm_daemon() 1447{ 1448 struct proc *p; 1449 1450 mtx_lock(&Giant); 1451 while (TRUE) { 1452 tsleep(&vm_daemon_needed, PPAUSE, "psleep", 0); 1453 if (vm_pageout_req_swapout) { 1454 swapout_procs(vm_pageout_req_swapout); 1455 vm_pageout_req_swapout = 0; 1456 } 1457 /* 1458 * scan the processes for exceeding their rlimits or if 1459 * process is swapped out -- deactivate pages 1460 */ 1461 sx_slock(&allproc_lock); 1462 LIST_FOREACH(p, &allproc, p_list) { 1463 vm_pindex_t limit, size; 1464 1465 /* 1466 * if this is a system process or if we have already 1467 * looked at this process, skip it. 1468 */ 1469 if (p->p_flag & (P_SYSTEM | P_WEXIT)) { 1470 continue; 1471 } 1472 /* 1473 * if the process is in a non-running type state, 1474 * don't touch it. 1475 */ 1476 mtx_lock_spin(&sched_lock); 1477 if (p->p_stat != SRUN && p->p_stat != SSLEEP) { 1478 mtx_unlock_spin(&sched_lock); 1479 continue; 1480 } 1481 /* 1482 * get a limit 1483 */ 1484 limit = OFF_TO_IDX( 1485 qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, 1486 p->p_rlimit[RLIMIT_RSS].rlim_max)); 1487 1488 /* 1489 * let processes that are swapped out really be 1490 * swapped out set the limit to nothing (will force a 1491 * swap-out.) 1492 */ 1493 if ((p->p_sflag & PS_INMEM) == 0) 1494 limit = 0; /* XXX */ 1495 mtx_unlock_spin(&sched_lock); 1496 1497 size = vmspace_resident_count(p->p_vmspace); 1498 if (limit >= 0 && size >= limit) { 1499 vm_pageout_map_deactivate_pages( 1500 &p->p_vmspace->vm_map, limit); 1501 } 1502 } 1503 sx_sunlock(&allproc_lock); 1504 } 1505} 1506#endif /* !defined(NO_SWAPPING) */
|