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sys/vm/vm_glue.c
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1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * The Mach Operating System project at Carnegie-Mellon University. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 37 * 38 * 39 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 40 * All rights reserved. 41 * 42 * Permission to use, copy, modify and distribute this software and 43 * its documentation is hereby granted, provided that both the copyright 44 * notice and this permission notice appear in all copies of the 45 * software, derivative works or modified versions, and any portions 46 * thereof, and that both notices appear in supporting documentation. 47 * 48 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 49 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 50 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 51 * 52 * Carnegie Mellon requests users of this software to return to 53 * 54 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 55 * School of Computer Science 56 * Carnegie Mellon University 57 * Pittsburgh PA 15213-3890 58 * 59 * any improvements or extensions that they make and grant Carnegie the 60 * rights to redistribute these changes. 61 * 62 * $FreeBSD: releng/5.0/sys/vm/vm_glue.c 105695 2002-10-22 14:31:32Z jhb $ 63 */ 64 65 #include "opt_vm.h" 66 67 #include <sys/param.h> 68 #include <sys/systm.h> 69 #include <sys/lock.h> 70 #include <sys/mutex.h> 71 #include <sys/proc.h> 72 #include <sys/resourcevar.h> 73 #include <sys/shm.h> 74 #include <sys/vmmeter.h> 75 #include <sys/sx.h> 76 #include <sys/sysctl.h> 77 78 #include <sys/kernel.h> 79 #include <sys/ktr.h> 80 #include <sys/unistd.h> 81 82 #include <machine/limits.h> 83 84 #include <vm/vm.h> 85 #include <vm/vm_param.h> 86 #include <vm/pmap.h> 87 #include <vm/vm_map.h> 88 #include <vm/vm_page.h> 89 #include <vm/vm_pageout.h> 90 #include <vm/vm_object.h> 91 #include <vm/vm_kern.h> 92 #include <vm/vm_extern.h> 93 #include <vm/vm_pager.h> 94 95 #include <sys/user.h> 96 97 extern int maxslp; 98 99 /* 100 * System initialization 101 * 102 * Note: proc0 from proc.h 103 */ 104 static void vm_init_limits(void *); 105 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 106 107 /* 108 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 109 * 110 * Note: run scheduling should be divorced from the vm system. 111 */ 112 static void scheduler(void *); 113 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 114 115 #ifndef NO_SWAPPING 116 static void swapout(struct proc *); 117 static void vm_proc_swapin(struct proc *p); 118 static void vm_proc_swapout(struct proc *p); 119 #endif 120 121 /* 122 * MPSAFE 123 */ 124 int 125 kernacc(addr, len, rw) 126 caddr_t addr; 127 int len, rw; 128 { 129 boolean_t rv; 130 vm_offset_t saddr, eaddr; 131 vm_prot_t prot; 132 133 KASSERT((rw & ~VM_PROT_ALL) == 0, 134 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 135 prot = rw; 136 saddr = trunc_page((vm_offset_t)addr); 137 eaddr = round_page((vm_offset_t)addr + len); 138 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 139 return (rv == TRUE); 140 } 141 142 /* 143 * MPSAFE 144 */ 145 int 146 useracc(addr, len, rw) 147 caddr_t addr; 148 int len, rw; 149 { 150 boolean_t rv; 151 vm_prot_t prot; 152 vm_map_t map; 153 154 KASSERT((rw & ~VM_PROT_ALL) == 0, 155 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 156 prot = rw; 157 map = &curproc->p_vmspace->vm_map; 158 if ((vm_offset_t)addr + len > vm_map_max(map) || 159 (vm_offset_t)addr + len < (vm_offset_t)addr) { 160 return (FALSE); 161 } 162 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 163 round_page((vm_offset_t)addr + len), prot); 164 return (rv == TRUE); 165 } 166 167 /* 168 * MPSAFE 169 */ 170 void 171 vslock(addr, len) 172 caddr_t addr; 173 u_int len; 174 { 175 176 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 177 round_page((vm_offset_t)addr + len), FALSE); 178 } 179 180 /* 181 * MPSAFE 182 */ 183 void 184 vsunlock(addr, len) 185 caddr_t addr; 186 u_int len; 187 { 188 189 vm_map_unwire(&curproc->p_vmspace->vm_map, 190 trunc_page((vm_offset_t)addr), 191 round_page((vm_offset_t)addr + len), FALSE); 192 } 193 194 /* 195 * Create the U area for a new process. 196 * This routine directly affects the fork perf for a process. 197 */ 198 void 199 vm_proc_new(struct proc *p) 200 { 201 vm_page_t ma[UAREA_PAGES]; 202 vm_object_t upobj; 203 vm_offset_t up; 204 vm_page_t m; 205 u_int i; 206 207 /* 208 * Allocate object for the upage. 209 */ 210 upobj = vm_object_allocate(OBJT_DEFAULT, UAREA_PAGES); 211 p->p_upages_obj = upobj; 212 213 /* 214 * Get a kernel virtual address for the U area for this process. 215 */ 216 up = kmem_alloc_nofault(kernel_map, UAREA_PAGES * PAGE_SIZE); 217 if (up == 0) 218 panic("vm_proc_new: upage allocation failed"); 219 p->p_uarea = (struct user *)up; 220 221 for (i = 0; i < UAREA_PAGES; i++) { 222 /* 223 * Get a uarea page. 224 */ 225 m = vm_page_grab(upobj, i, 226 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 227 ma[i] = m; 228 229 vm_page_wakeup(m); 230 vm_page_flag_clear(m, PG_ZERO); 231 m->valid = VM_PAGE_BITS_ALL; 232 } 233 234 /* 235 * Enter the pages into the kernel address space. 236 */ 237 pmap_qenter(up, ma, UAREA_PAGES); 238 } 239 240 /* 241 * Dispose the U area for a process that has exited. 242 * This routine directly impacts the exit perf of a process. 243 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 244 */ 245 void 246 vm_proc_dispose(struct proc *p) 247 { 248 vm_object_t upobj; 249 vm_offset_t up; 250 vm_page_t m; 251 252 upobj = p->p_upages_obj; 253 if (upobj->resident_page_count != UAREA_PAGES) 254 panic("vm_proc_dispose: incorrect number of pages in upobj"); 255 vm_page_lock_queues(); 256 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 257 vm_page_busy(m); 258 vm_page_unwire(m, 0); 259 vm_page_free(m); 260 } 261 vm_page_unlock_queues(); 262 up = (vm_offset_t)p->p_uarea; 263 pmap_qremove(up, UAREA_PAGES); 264 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 265 vm_object_deallocate(upobj); 266 } 267 268 #ifndef NO_SWAPPING 269 /* 270 * Allow the U area for a process to be prejudicially paged out. 271 */ 272 static void 273 vm_proc_swapout(struct proc *p) 274 { 275 vm_object_t upobj; 276 vm_offset_t up; 277 vm_page_t m; 278 279 upobj = p->p_upages_obj; 280 if (upobj->resident_page_count != UAREA_PAGES) 281 panic("vm_proc_dispose: incorrect number of pages in upobj"); 282 vm_page_lock_queues(); 283 TAILQ_FOREACH(m, &upobj->memq, listq) { 284 vm_page_dirty(m); 285 vm_page_unwire(m, 0); 286 } 287 vm_page_unlock_queues(); 288 up = (vm_offset_t)p->p_uarea; 289 pmap_qremove(up, UAREA_PAGES); 290 } 291 292 /* 293 * Bring the U area for a specified process back in. 294 */ 295 static void 296 vm_proc_swapin(struct proc *p) 297 { 298 vm_page_t ma[UAREA_PAGES]; 299 vm_object_t upobj; 300 vm_offset_t up; 301 vm_page_t m; 302 int rv; 303 int i; 304 305 upobj = p->p_upages_obj; 306 for (i = 0; i < UAREA_PAGES; i++) { 307 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 308 if (m->valid != VM_PAGE_BITS_ALL) { 309 rv = vm_pager_get_pages(upobj, &m, 1, 0); 310 if (rv != VM_PAGER_OK) 311 panic("vm_proc_swapin: cannot get upage"); 312 } 313 ma[i] = m; 314 } 315 if (upobj->resident_page_count != UAREA_PAGES) 316 panic("vm_proc_swapin: lost pages from upobj"); 317 vm_page_lock_queues(); 318 TAILQ_FOREACH(m, &upobj->memq, listq) { 319 m->valid = VM_PAGE_BITS_ALL; 320 vm_page_wire(m); 321 vm_page_wakeup(m); 322 } 323 vm_page_unlock_queues(); 324 up = (vm_offset_t)p->p_uarea; 325 pmap_qenter(up, ma, UAREA_PAGES); 326 } 327 #endif 328 329 /* 330 * Implement fork's actions on an address space. 331 * Here we arrange for the address space to be copied or referenced, 332 * allocate a user struct (pcb and kernel stack), then call the 333 * machine-dependent layer to fill those in and make the new process 334 * ready to run. The new process is set up so that it returns directly 335 * to user mode to avoid stack copying and relocation problems. 336 */ 337 void 338 vm_forkproc(td, p2, td2, flags) 339 struct thread *td; 340 struct proc *p2; 341 struct thread *td2; 342 int flags; 343 { 344 struct proc *p1 = td->td_proc; 345 struct user *up; 346 347 GIANT_REQUIRED; 348 349 if ((flags & RFPROC) == 0) { 350 /* 351 * Divorce the memory, if it is shared, essentially 352 * this changes shared memory amongst threads, into 353 * COW locally. 354 */ 355 if ((flags & RFMEM) == 0) { 356 if (p1->p_vmspace->vm_refcnt > 1) { 357 vmspace_unshare(p1); 358 } 359 } 360 cpu_fork(td, p2, td2, flags); 361 return; 362 } 363 364 if (flags & RFMEM) { 365 p2->p_vmspace = p1->p_vmspace; 366 p1->p_vmspace->vm_refcnt++; 367 } 368 369 while (vm_page_count_severe()) { 370 VM_WAIT; 371 } 372 373 if ((flags & RFMEM) == 0) { 374 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 375 376 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 377 378 if (p1->p_vmspace->vm_shm) 379 shmfork(p1, p2); 380 } 381 382 /* XXXKSE this is unsatisfactory but should be adequate */ 383 up = p2->p_uarea; 384 385 /* 386 * p_stats currently points at fields in the user struct 387 * but not at &u, instead at p_addr. Copy parts of 388 * p_stats; zero the rest of p_stats (statistics). 389 * 390 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 391 * to share sigacts, so we use the up->u_sigacts. 392 */ 393 p2->p_stats = &up->u_stats; 394 if (p2->p_sigacts == NULL) { 395 if (p2->p_procsig->ps_refcnt != 1) 396 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 397 p2->p_sigacts = &up->u_sigacts; 398 up->u_sigacts = *p1->p_sigacts; 399 } 400 401 bzero(&up->u_stats.pstat_startzero, 402 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 403 (caddr_t) &up->u_stats.pstat_startzero)); 404 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 405 ((caddr_t) &up->u_stats.pstat_endcopy - 406 (caddr_t) &up->u_stats.pstat_startcopy)); 407 408 409 /* 410 * cpu_fork will copy and update the pcb, set up the kernel stack, 411 * and make the child ready to run. 412 */ 413 cpu_fork(td, p2, td2, flags); 414 } 415 416 /* 417 * Called after process has been wait(2)'ed apon and is being reaped. 418 * The idea is to reclaim resources that we could not reclaim while 419 * the process was still executing. 420 */ 421 void 422 vm_waitproc(p) 423 struct proc *p; 424 { 425 426 GIANT_REQUIRED; 427 cpu_wait(p); 428 vmspace_exitfree(p); /* and clean-out the vmspace */ 429 } 430 431 /* 432 * Set default limits for VM system. 433 * Called for proc 0, and then inherited by all others. 434 * 435 * XXX should probably act directly on proc0. 436 */ 437 static void 438 vm_init_limits(udata) 439 void *udata; 440 { 441 struct proc *p = udata; 442 int rss_limit; 443 444 /* 445 * Set up the initial limits on process VM. Set the maximum resident 446 * set size to be half of (reasonably) available memory. Since this 447 * is a soft limit, it comes into effect only when the system is out 448 * of memory - half of main memory helps to favor smaller processes, 449 * and reduces thrashing of the object cache. 450 */ 451 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 452 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 453 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 454 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 455 /* limit the limit to no less than 2MB */ 456 rss_limit = max(cnt.v_free_count, 512); 457 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 458 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 459 } 460 461 void 462 faultin(p) 463 struct proc *p; 464 { 465 466 GIANT_REQUIRED; 467 PROC_LOCK_ASSERT(p, MA_OWNED); 468 mtx_assert(&sched_lock, MA_OWNED); 469 #ifdef NO_SWAPPING 470 if ((p->p_sflag & PS_INMEM) == 0) 471 panic("faultin: proc swapped out with NO_SWAPPING!"); 472 #else 473 if ((p->p_sflag & PS_INMEM) == 0) { 474 struct thread *td; 475 476 ++p->p_lock; 477 /* 478 * If another process is swapping in this process, 479 * just wait until it finishes. 480 */ 481 if (p->p_sflag & PS_SWAPPINGIN) { 482 mtx_unlock_spin(&sched_lock); 483 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 484 mtx_lock_spin(&sched_lock); 485 --p->p_lock; 486 return; 487 } 488 489 p->p_sflag |= PS_SWAPPINGIN; 490 mtx_unlock_spin(&sched_lock); 491 PROC_UNLOCK(p); 492 493 vm_proc_swapin(p); 494 FOREACH_THREAD_IN_PROC (p, td) { 495 pmap_swapin_thread(td); 496 TD_CLR_SWAPPED(td); 497 } 498 499 PROC_LOCK(p); 500 mtx_lock_spin(&sched_lock); 501 p->p_sflag &= ~PS_SWAPPINGIN; 502 p->p_sflag |= PS_INMEM; 503 FOREACH_THREAD_IN_PROC (p, td) 504 if (TD_CAN_RUN(td)) 505 setrunnable(td); 506 507 wakeup(&p->p_sflag); 508 509 /* undo the effect of setting SLOCK above */ 510 --p->p_lock; 511 } 512 #endif 513 } 514 515 /* 516 * This swapin algorithm attempts to swap-in processes only if there 517 * is enough space for them. Of course, if a process waits for a long 518 * time, it will be swapped in anyway. 519 * 520 * XXXKSE - process with the thread with highest priority counts.. 521 * 522 * Giant is still held at this point, to be released in tsleep. 523 */ 524 /* ARGSUSED*/ 525 static void 526 scheduler(dummy) 527 void *dummy; 528 { 529 struct proc *p; 530 struct thread *td; 531 int pri; 532 struct proc *pp; 533 int ppri; 534 535 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 536 /* GIANT_REQUIRED */ 537 538 loop: 539 if (vm_page_count_min()) { 540 VM_WAIT; 541 goto loop; 542 } 543 544 pp = NULL; 545 ppri = INT_MIN; 546 sx_slock(&allproc_lock); 547 FOREACH_PROC_IN_SYSTEM(p) { 548 struct ksegrp *kg; 549 if (p->p_sflag & (PS_INMEM | PS_SWAPPING | PS_SWAPPINGIN)) { 550 continue; 551 } 552 mtx_lock_spin(&sched_lock); 553 FOREACH_THREAD_IN_PROC(p, td) { 554 /* 555 * An otherwise runnable thread of a process 556 * swapped out has only the TDI_SWAPPED bit set. 557 * 558 */ 559 if (td->td_inhibitors == TDI_SWAPPED) { 560 kg = td->td_ksegrp; 561 pri = p->p_swtime + kg->kg_slptime; 562 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 563 pri -= kg->kg_nice * 8; 564 } 565 566 /* 567 * if this ksegrp is higher priority 568 * and there is enough space, then select 569 * this process instead of the previous 570 * selection. 571 */ 572 if (pri > ppri) { 573 pp = p; 574 ppri = pri; 575 } 576 } 577 } 578 mtx_unlock_spin(&sched_lock); 579 } 580 sx_sunlock(&allproc_lock); 581 582 /* 583 * Nothing to do, back to sleep. 584 */ 585 if ((p = pp) == NULL) { 586 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 587 goto loop; 588 } 589 PROC_LOCK(p); 590 mtx_lock_spin(&sched_lock); 591 592 /* 593 * Another process may be bringing or may have already 594 * brought this process in while we traverse all threads. 595 * Or, this process may even be being swapped out again. 596 */ 597 if (p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) { 598 mtx_unlock_spin(&sched_lock); 599 PROC_UNLOCK(p); 600 goto loop; 601 } 602 603 p->p_sflag &= ~PS_SWAPINREQ; 604 605 /* 606 * We would like to bring someone in. (only if there is space). 607 * [What checks the space? ] 608 */ 609 faultin(p); 610 PROC_UNLOCK(p); 611 p->p_swtime = 0; 612 mtx_unlock_spin(&sched_lock); 613 goto loop; 614 } 615 616 #ifndef NO_SWAPPING 617 618 /* 619 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 620 */ 621 static int swap_idle_threshold1 = 2; 622 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 623 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 624 625 /* 626 * Swap_idle_threshold2 is the time that a process can be idle before 627 * it will be swapped out, if idle swapping is enabled. 628 */ 629 static int swap_idle_threshold2 = 10; 630 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 631 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 632 633 /* 634 * Swapout is driven by the pageout daemon. Very simple, we find eligible 635 * procs and unwire their u-areas. We try to always "swap" at least one 636 * process in case we need the room for a swapin. 637 * If any procs have been sleeping/stopped for at least maxslp seconds, 638 * they are swapped. Else, we swap the longest-sleeping or stopped process, 639 * if any, otherwise the longest-resident process. 640 */ 641 void 642 swapout_procs(action) 643 int action; 644 { 645 struct proc *p; 646 struct thread *td; 647 struct ksegrp *kg; 648 struct proc *outp, *outp2; 649 int outpri, outpri2; 650 int didswap = 0; 651 652 GIANT_REQUIRED; 653 654 outp = outp2 = NULL; 655 outpri = outpri2 = INT_MIN; 656 retry: 657 sx_slock(&allproc_lock); 658 FOREACH_PROC_IN_SYSTEM(p) { 659 struct vmspace *vm; 660 int minslptime = 100000; 661 662 /* 663 * Watch out for a process in 664 * creation. It may have no 665 * address space or lock yet. 666 */ 667 mtx_lock_spin(&sched_lock); 668 if (p->p_state == PRS_NEW) { 669 mtx_unlock_spin(&sched_lock); 670 continue; 671 } 672 mtx_unlock_spin(&sched_lock); 673 674 /* 675 * An aio daemon switches its 676 * address space while running. 677 * Perform a quick check whether 678 * a process has P_SYSTEM. 679 */ 680 PROC_LOCK(p); 681 if ((p->p_flag & P_SYSTEM) != 0) { 682 PROC_UNLOCK(p); 683 continue; 684 } 685 686 /* 687 * Do not swapout a process that 688 * is waiting for VM data 689 * structures as there is a possible 690 * deadlock. Test this first as 691 * this may block. 692 * 693 * Lock the map until swapout 694 * finishes, or a thread of this 695 * process may attempt to alter 696 * the map. 697 */ 698 vm = p->p_vmspace; 699 KASSERT(vm != NULL, 700 ("swapout_procs: a process has no address space")); 701 ++vm->vm_refcnt; 702 PROC_UNLOCK(p); 703 if (!vm_map_trylock(&vm->vm_map)) 704 goto nextproc1; 705 706 PROC_LOCK(p); 707 if (p->p_lock != 0 || 708 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) 709 ) != 0) { 710 goto nextproc2; 711 } 712 /* 713 * only aiod changes vmspace, however it will be 714 * skipped because of the if statement above checking 715 * for P_SYSTEM 716 */ 717 mtx_lock_spin(&sched_lock); 718 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) != PS_INMEM) 719 goto nextproc; 720 721 switch (p->p_state) { 722 default: 723 /* Don't swap out processes in any sort 724 * of 'special' state. */ 725 goto nextproc; 726 727 case PRS_NORMAL: 728 /* 729 * do not swapout a realtime process 730 * Check all the thread groups.. 731 */ 732 FOREACH_KSEGRP_IN_PROC(p, kg) { 733 if (PRI_IS_REALTIME(kg->kg_pri_class)) 734 goto nextproc; 735 736 /* 737 * Guarantee swap_idle_threshold1 738 * time in memory. 739 */ 740 if (kg->kg_slptime < swap_idle_threshold1) 741 goto nextproc; 742 743 /* 744 * Do not swapout a process if it is 745 * waiting on a critical event of some 746 * kind or there is a thread whose 747 * pageable memory may be accessed. 748 * 749 * This could be refined to support 750 * swapping out a thread. 751 */ 752 FOREACH_THREAD_IN_GROUP(kg, td) { 753 if ((td->td_priority) < PSOCK || 754 !thread_safetoswapout(td)) 755 goto nextproc; 756 } 757 /* 758 * If the system is under memory stress, 759 * or if we are swapping 760 * idle processes >= swap_idle_threshold2, 761 * then swap the process out. 762 */ 763 if (((action & VM_SWAP_NORMAL) == 0) && 764 (((action & VM_SWAP_IDLE) == 0) || 765 (kg->kg_slptime < swap_idle_threshold2))) 766 goto nextproc; 767 768 if (minslptime > kg->kg_slptime) 769 minslptime = kg->kg_slptime; 770 } 771 772 /* 773 * If the process has been asleep for awhile and had 774 * most of its pages taken away already, swap it out. 775 */ 776 if ((action & VM_SWAP_NORMAL) || 777 ((action & VM_SWAP_IDLE) && 778 (minslptime > swap_idle_threshold2))) { 779 swapout(p); 780 didswap++; 781 782 /* 783 * swapout() unlocks a proc lock. This is 784 * ugly, but avoids superfluous lock. 785 */ 786 mtx_unlock_spin(&sched_lock); 787 vm_map_unlock(&vm->vm_map); 788 vmspace_free(vm); 789 sx_sunlock(&allproc_lock); 790 goto retry; 791 } 792 } 793 nextproc: 794 mtx_unlock_spin(&sched_lock); 795 nextproc2: 796 PROC_UNLOCK(p); 797 vm_map_unlock(&vm->vm_map); 798 nextproc1: 799 vmspace_free(vm); 800 continue; 801 } 802 sx_sunlock(&allproc_lock); 803 /* 804 * If we swapped something out, and another process needed memory, 805 * then wakeup the sched process. 806 */ 807 if (didswap) 808 wakeup(&proc0); 809 } 810 811 static void 812 swapout(p) 813 struct proc *p; 814 { 815 struct thread *td; 816 817 PROC_LOCK_ASSERT(p, MA_OWNED); 818 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 819 #if defined(SWAP_DEBUG) 820 printf("swapping out %d\n", p->p_pid); 821 #endif 822 823 /* 824 * The states of this process and its threads may have changed 825 * by now. Assuming that there is only one pageout daemon thread, 826 * this process should still be in memory. 827 */ 828 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) == PS_INMEM, 829 ("swapout: lost a swapout race?")); 830 831 #if defined(INVARIANTS) 832 /* 833 * Make sure that all threads are safe to be swapped out. 834 * 835 * Alternatively, we could swap out only safe threads. 836 */ 837 FOREACH_THREAD_IN_PROC(p, td) { 838 KASSERT(thread_safetoswapout(td), 839 ("swapout: there is a thread not safe for swapout")); 840 } 841 #endif /* INVARIANTS */ 842 843 ++p->p_stats->p_ru.ru_nswap; 844 /* 845 * remember the process resident count 846 */ 847 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 848 849 PROC_UNLOCK(p); 850 p->p_sflag &= ~PS_INMEM; 851 p->p_sflag |= PS_SWAPPING; 852 mtx_unlock_spin(&sched_lock); 853 854 vm_proc_swapout(p); 855 FOREACH_THREAD_IN_PROC(p, td) { 856 pmap_swapout_thread(td); 857 TD_SET_SWAPPED(td); 858 } 859 mtx_lock_spin(&sched_lock); 860 p->p_sflag &= ~PS_SWAPPING; 861 p->p_swtime = 0; 862 } 863 #endif /* !NO_SWAPPING */
Cache object: 940a3ff0bedcacdfc919ce1d1cc7d0cb
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