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 * $FreeBSD$ 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; 152 153 KASSERT((rw & ~VM_PROT_ALL) == 0, 154 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 155 prot = rw; 156 /* 157 * XXX - check separately to disallow access to user area and user 158 * page tables - they are in the map. 159 * 160 * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once 161 * only used (as an end address) in trap.c. Use it as an end address 162 * here too. This bogusness has spread. I just fixed where it was 163 * used as a max in vm_mmap.c. 164 */ 165 if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS 166 || (vm_offset_t) addr + len < (vm_offset_t) addr) { 167 return (FALSE); 168 } 169 rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, 170 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 171 prot); 172 return (rv == TRUE); 173 } 174 175 /* 176 * MPSAFE 177 */ 178 void 179 vslock(addr, len) 180 caddr_t addr; 181 u_int len; 182 { 183 184 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 185 round_page((vm_offset_t)addr + len), FALSE); 186 } 187 188 /* 189 * MPSAFE 190 */ 191 void 192 vsunlock(addr, len) 193 caddr_t addr; 194 u_int len; 195 { 196 197 vm_map_unwire(&curproc->p_vmspace->vm_map, 198 trunc_page((vm_offset_t)addr), 199 round_page((vm_offset_t)addr + len), FALSE); 200 } 201 202 /* 203 * Create the U area for a new process. 204 * This routine directly affects the fork perf for a process. 205 */ 206 void 207 vm_proc_new(struct proc *p) 208 { 209 vm_page_t ma[UAREA_PAGES]; 210 vm_object_t upobj; 211 vm_offset_t up; 212 vm_page_t m; 213 u_int i; 214 215 /* 216 * Allocate object for the upage. 217 */ 218 upobj = vm_object_allocate(OBJT_DEFAULT, UAREA_PAGES); 219 p->p_upages_obj = upobj; 220 221 /* 222 * Get a kernel virtual address for the U area for this process. 223 */ 224 up = kmem_alloc_nofault(kernel_map, UAREA_PAGES * PAGE_SIZE); 225 if (up == 0) 226 panic("vm_proc_new: upage allocation failed"); 227 p->p_uarea = (struct user *)up; 228 229 for (i = 0; i < UAREA_PAGES; i++) { 230 /* 231 * Get a uarea page. 232 */ 233 m = vm_page_grab(upobj, i, 234 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 235 ma[i] = m; 236 237 vm_page_wakeup(m); 238 vm_page_flag_clear(m, PG_ZERO); 239 m->valid = VM_PAGE_BITS_ALL; 240 } 241 242 /* 243 * Enter the pages into the kernel address space. 244 */ 245 pmap_qenter(up, ma, UAREA_PAGES); 246 } 247 248 /* 249 * Dispose the U area for a process that has exited. 250 * This routine directly impacts the exit perf of a process. 251 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 252 */ 253 void 254 vm_proc_dispose(struct proc *p) 255 { 256 vm_object_t upobj; 257 vm_offset_t up; 258 vm_page_t m; 259 260 upobj = p->p_upages_obj; 261 if (upobj->resident_page_count != UAREA_PAGES) 262 panic("vm_proc_dispose: incorrect number of pages in upobj"); 263 vm_page_lock_queues(); 264 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 265 vm_page_busy(m); 266 vm_page_unwire(m, 0); 267 vm_page_free(m); 268 } 269 vm_page_unlock_queues(); 270 up = (vm_offset_t)p->p_uarea; 271 pmap_qremove(up, UAREA_PAGES); 272 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 273 vm_object_deallocate(upobj); 274 } 275 276 #ifndef NO_SWAPPING 277 /* 278 * Allow the U area for a process to be prejudicially paged out. 279 */ 280 void 281 vm_proc_swapout(struct proc *p) 282 { 283 vm_object_t upobj; 284 vm_offset_t up; 285 vm_page_t m; 286 287 upobj = p->p_upages_obj; 288 if (upobj->resident_page_count != UAREA_PAGES) 289 panic("vm_proc_dispose: incorrect number of pages in upobj"); 290 vm_page_lock_queues(); 291 TAILQ_FOREACH(m, &upobj->memq, listq) { 292 vm_page_dirty(m); 293 vm_page_unwire(m, 0); 294 } 295 vm_page_unlock_queues(); 296 up = (vm_offset_t)p->p_uarea; 297 pmap_qremove(up, UAREA_PAGES); 298 } 299 300 /* 301 * Bring the U area for a specified process back in. 302 */ 303 void 304 vm_proc_swapin(struct proc *p) 305 { 306 vm_page_t ma[UAREA_PAGES]; 307 vm_object_t upobj; 308 vm_offset_t up; 309 vm_page_t m; 310 int rv; 311 int i; 312 313 upobj = p->p_upages_obj; 314 for (i = 0; i < UAREA_PAGES; i++) { 315 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 316 if (m->valid != VM_PAGE_BITS_ALL) { 317 rv = vm_pager_get_pages(upobj, &m, 1, 0); 318 if (rv != VM_PAGER_OK) 319 panic("vm_proc_swapin: cannot get upage"); 320 } 321 ma[i] = m; 322 } 323 if (upobj->resident_page_count != UAREA_PAGES) 324 panic("vm_proc_swapin: lost pages from upobj"); 325 vm_page_lock_queues(); 326 TAILQ_FOREACH(m, &upobj->memq, listq) { 327 m->valid = VM_PAGE_BITS_ALL; 328 vm_page_wire(m); 329 vm_page_wakeup(m); 330 } 331 vm_page_unlock_queues(); 332 up = (vm_offset_t)p->p_uarea; 333 pmap_qenter(up, ma, UAREA_PAGES); 334 } 335 #endif 336 337 /* 338 * Implement fork's actions on an address space. 339 * Here we arrange for the address space to be copied or referenced, 340 * allocate a user struct (pcb and kernel stack), then call the 341 * machine-dependent layer to fill those in and make the new process 342 * ready to run. The new process is set up so that it returns directly 343 * to user mode to avoid stack copying and relocation problems. 344 */ 345 void 346 vm_forkproc(td, p2, td2, flags) 347 struct thread *td; 348 struct proc *p2; 349 struct thread *td2; 350 int flags; 351 { 352 struct proc *p1 = td->td_proc; 353 struct user *up; 354 355 GIANT_REQUIRED; 356 357 if ((flags & RFPROC) == 0) { 358 /* 359 * Divorce the memory, if it is shared, essentially 360 * this changes shared memory amongst threads, into 361 * COW locally. 362 */ 363 if ((flags & RFMEM) == 0) { 364 if (p1->p_vmspace->vm_refcnt > 1) { 365 vmspace_unshare(p1); 366 } 367 } 368 cpu_fork(td, p2, td2, flags); 369 return; 370 } 371 372 if (flags & RFMEM) { 373 p2->p_vmspace = p1->p_vmspace; 374 p1->p_vmspace->vm_refcnt++; 375 } 376 377 while (vm_page_count_severe()) { 378 VM_WAIT; 379 } 380 381 if ((flags & RFMEM) == 0) { 382 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 383 384 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 385 386 if (p1->p_vmspace->vm_shm) 387 shmfork(p1, p2); 388 } 389 390 /* XXXKSE this is unsatisfactory but should be adequate */ 391 up = p2->p_uarea; 392 393 /* 394 * p_stats currently points at fields in the user struct 395 * but not at &u, instead at p_addr. Copy parts of 396 * p_stats; zero the rest of p_stats (statistics). 397 * 398 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 399 * to share sigacts, so we use the up->u_sigacts. 400 */ 401 p2->p_stats = &up->u_stats; 402 if (p2->p_sigacts == NULL) { 403 if (p2->p_procsig->ps_refcnt != 1) 404 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 405 p2->p_sigacts = &up->u_sigacts; 406 up->u_sigacts = *p1->p_sigacts; 407 } 408 409 bzero(&up->u_stats.pstat_startzero, 410 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 411 (caddr_t) &up->u_stats.pstat_startzero)); 412 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 413 ((caddr_t) &up->u_stats.pstat_endcopy - 414 (caddr_t) &up->u_stats.pstat_startcopy)); 415 416 417 /* 418 * cpu_fork will copy and update the pcb, set up the kernel stack, 419 * and make the child ready to run. 420 */ 421 cpu_fork(td, p2, td2, flags); 422 } 423 424 /* 425 * Called after process has been wait(2)'ed apon and is being reaped. 426 * The idea is to reclaim resources that we could not reclaim while 427 * the process was still executing. 428 */ 429 void 430 vm_waitproc(p) 431 struct proc *p; 432 { 433 struct thread *td; 434 435 GIANT_REQUIRED; 436 cpu_wait(p); 437 /* XXXKSE by here there should not be any threads left! */ 438 FOREACH_THREAD_IN_PROC(p, td) { 439 panic("vm_waitproc: Survivor thread!"); 440 } 441 vmspace_exitfree(p); /* and clean-out the vmspace */ 442 } 443 444 /* 445 * Set default limits for VM system. 446 * Called for proc 0, and then inherited by all others. 447 * 448 * XXX should probably act directly on proc0. 449 */ 450 static void 451 vm_init_limits(udata) 452 void *udata; 453 { 454 struct proc *p = udata; 455 int rss_limit; 456 457 /* 458 * Set up the initial limits on process VM. Set the maximum resident 459 * set size to be half of (reasonably) available memory. Since this 460 * is a soft limit, it comes into effect only when the system is out 461 * of memory - half of main memory helps to favor smaller processes, 462 * and reduces thrashing of the object cache. 463 */ 464 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 465 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 466 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 467 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 468 /* limit the limit to no less than 2MB */ 469 rss_limit = max(cnt.v_free_count, 512); 470 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 471 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 472 } 473 474 void 475 faultin(p) 476 struct proc *p; 477 { 478 479 GIANT_REQUIRED; 480 PROC_LOCK_ASSERT(p, MA_OWNED); 481 mtx_assert(&sched_lock, MA_OWNED); 482 #ifdef NO_SWAPPING 483 if ((p->p_sflag & PS_INMEM) == 0) 484 panic("faultin: proc swapped out with NO_SWAPPING!"); 485 #else 486 if ((p->p_sflag & PS_INMEM) == 0) { 487 struct thread *td; 488 489 ++p->p_lock; 490 /* 491 * If another process is swapping in this process, 492 * just wait until it finishes. 493 */ 494 if (p->p_sflag & PS_SWAPPINGIN) { 495 mtx_unlock_spin(&sched_lock); 496 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 497 mtx_lock_spin(&sched_lock); 498 --p->p_lock; 499 return; 500 } 501 502 p->p_sflag |= PS_SWAPPINGIN; 503 mtx_unlock_spin(&sched_lock); 504 PROC_UNLOCK(p); 505 506 vm_proc_swapin(p); 507 FOREACH_THREAD_IN_PROC (p, td) 508 pmap_swapin_thread(td); 509 510 PROC_LOCK(p); 511 mtx_lock_spin(&sched_lock); 512 p->p_sflag &= ~PS_SWAPPINGIN; 513 p->p_sflag |= PS_INMEM; 514 FOREACH_THREAD_IN_PROC (p, td) 515 if (td->td_state == TDS_SWAPPED) 516 setrunqueue(td); 517 518 wakeup(&p->p_sflag); 519 520 /* undo the effect of setting SLOCK above */ 521 --p->p_lock; 522 } 523 #endif 524 } 525 526 /* 527 * This swapin algorithm attempts to swap-in processes only if there 528 * is enough space for them. Of course, if a process waits for a long 529 * time, it will be swapped in anyway. 530 * 531 * XXXKSE - process with the thread with highest priority counts.. 532 * 533 * Giant is still held at this point, to be released in tsleep. 534 */ 535 /* ARGSUSED*/ 536 static void 537 scheduler(dummy) 538 void *dummy; 539 { 540 struct proc *p; 541 struct thread *td; 542 int pri; 543 struct proc *pp; 544 int ppri; 545 546 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 547 /* GIANT_REQUIRED */ 548 549 loop: 550 if (vm_page_count_min()) { 551 VM_WAIT; 552 goto loop; 553 } 554 555 pp = NULL; 556 ppri = INT_MIN; 557 sx_slock(&allproc_lock); 558 FOREACH_PROC_IN_SYSTEM(p) { 559 struct ksegrp *kg; 560 if (p->p_sflag & (PS_INMEM | PS_SWAPPING | PS_SWAPPINGIN)) { 561 continue; 562 } 563 mtx_lock_spin(&sched_lock); 564 FOREACH_THREAD_IN_PROC(p, td) { 565 /* 566 * A runnable thread of a process swapped out is in 567 * TDS_SWAPPED. 568 */ 569 if (td->td_state == TDS_SWAPPED) { 570 kg = td->td_ksegrp; 571 pri = p->p_swtime + kg->kg_slptime; 572 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 573 pri -= kg->kg_nice * 8; 574 } 575 576 /* 577 * if this ksegrp is higher priority 578 * and there is enough space, then select 579 * this process instead of the previous 580 * selection. 581 */ 582 if (pri > ppri) { 583 pp = p; 584 ppri = pri; 585 } 586 } 587 } 588 mtx_unlock_spin(&sched_lock); 589 } 590 sx_sunlock(&allproc_lock); 591 592 /* 593 * Nothing to do, back to sleep. 594 */ 595 if ((p = pp) == NULL) { 596 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 597 goto loop; 598 } 599 PROC_LOCK(p); 600 mtx_lock_spin(&sched_lock); 601 602 /* 603 * Another process may be bringing or may have already 604 * brought this process in while we traverse all threads. 605 * Or, this process may even be being swapped out again. 606 */ 607 if (p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) { 608 mtx_unlock_spin(&sched_lock); 609 PROC_UNLOCK(p); 610 goto loop; 611 } 612 613 p->p_sflag &= ~PS_SWAPINREQ; 614 615 /* 616 * We would like to bring someone in. (only if there is space). 617 * [What checks the space? ] 618 */ 619 faultin(p); 620 PROC_UNLOCK(p); 621 p->p_swtime = 0; 622 mtx_unlock_spin(&sched_lock); 623 goto loop; 624 } 625 626 #ifndef NO_SWAPPING 627 628 /* 629 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 630 */ 631 static int swap_idle_threshold1 = 2; 632 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 633 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 634 635 /* 636 * Swap_idle_threshold2 is the time that a process can be idle before 637 * it will be swapped out, if idle swapping is enabled. 638 */ 639 static int swap_idle_threshold2 = 10; 640 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 641 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 642 643 /* 644 * Swapout is driven by the pageout daemon. Very simple, we find eligible 645 * procs and unwire their u-areas. We try to always "swap" at least one 646 * process in case we need the room for a swapin. 647 * If any procs have been sleeping/stopped for at least maxslp seconds, 648 * they are swapped. Else, we swap the longest-sleeping or stopped process, 649 * if any, otherwise the longest-resident process. 650 */ 651 void 652 swapout_procs(action) 653 int action; 654 { 655 struct proc *p; 656 struct thread *td; 657 struct ksegrp *kg; 658 struct proc *outp, *outp2; 659 int outpri, outpri2; 660 int didswap = 0; 661 662 GIANT_REQUIRED; 663 664 outp = outp2 = NULL; 665 outpri = outpri2 = INT_MIN; 666 retry: 667 sx_slock(&allproc_lock); 668 FOREACH_PROC_IN_SYSTEM(p) { 669 struct vmspace *vm; 670 int minslptime = 100000; 671 672 /* 673 * Do not swapout a process that 674 * is waiting for VM data 675 * structures there is a possible 676 * deadlock. Test this first as 677 * this may block. 678 * 679 * Lock the map until swapout 680 * finishes, or a thread of this 681 * process may attempt to alter 682 * the map. 683 */ 684 vm = p->p_vmspace; 685 ++vm->vm_refcnt; 686 if (!vm_map_trylock(&vm->vm_map)) 687 goto nextproc1; 688 689 PROC_LOCK(p); 690 if (p->p_lock != 0 || 691 (p->p_flag & (P_STOPPED_SNGL|P_TRACED|P_SYSTEM|P_WEXIT)) != 0) { 692 goto nextproc2; 693 } 694 /* 695 * only aiod changes vmspace, however it will be 696 * skipped because of the if statement above checking 697 * for P_SYSTEM 698 */ 699 mtx_lock_spin(&sched_lock); 700 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) != PS_INMEM) 701 goto nextproc; 702 703 switch (p->p_state) { 704 default: 705 /* Don't swap out processes in any sort 706 * of 'special' state. */ 707 goto nextproc; 708 709 case PRS_NORMAL: 710 /* 711 * do not swapout a realtime process 712 * Check all the thread groups.. 713 */ 714 FOREACH_KSEGRP_IN_PROC(p, kg) { 715 if (PRI_IS_REALTIME(kg->kg_pri_class)) 716 goto nextproc; 717 718 /* 719 * Guarantee swap_idle_threshold1 720 * time in memory. 721 */ 722 if (kg->kg_slptime < swap_idle_threshold1) 723 goto nextproc; 724 725 /* 726 * Do not swapout a process if it is 727 * waiting on a critical event of some 728 * kind or there is a thread whose 729 * pageable memory may be accessed. 730 * 731 * This could be refined to support 732 * swapping out a thread. 733 */ 734 FOREACH_THREAD_IN_GROUP(kg, td) { 735 if ((td->td_priority) < PSOCK || 736 !thread_safetoswapout(td)) 737 goto nextproc; 738 } 739 /* 740 * If the system is under memory stress, 741 * or if we are swapping 742 * idle processes >= swap_idle_threshold2, 743 * then swap the process out. 744 */ 745 if (((action & VM_SWAP_NORMAL) == 0) && 746 (((action & VM_SWAP_IDLE) == 0) || 747 (kg->kg_slptime < swap_idle_threshold2))) 748 goto nextproc; 749 750 if (minslptime > kg->kg_slptime) 751 minslptime = kg->kg_slptime; 752 } 753 754 /* 755 * If the process has been asleep for awhile and had 756 * most of its pages taken away already, swap it out. 757 */ 758 if ((action & VM_SWAP_NORMAL) || 759 ((action & VM_SWAP_IDLE) && 760 (minslptime > swap_idle_threshold2))) { 761 swapout(p); 762 didswap++; 763 764 /* 765 * swapout() unlocks a proc lock. This is 766 * ugly, but avoids superfluous lock. 767 */ 768 mtx_unlock_spin(&sched_lock); 769 vm_map_unlock(&vm->vm_map); 770 vmspace_free(vm); 771 sx_sunlock(&allproc_lock); 772 goto retry; 773 } 774 } 775 nextproc: 776 mtx_unlock_spin(&sched_lock); 777 nextproc2: 778 PROC_UNLOCK(p); 779 vm_map_unlock(&vm->vm_map); 780 nextproc1: 781 vmspace_free(vm); 782 continue; 783 } 784 sx_sunlock(&allproc_lock); 785 /* 786 * If we swapped something out, and another process needed memory, 787 * then wakeup the sched process. 788 */ 789 if (didswap) 790 wakeup(&proc0); 791 } 792 793 static void 794 swapout(p) 795 struct proc *p; 796 { 797 struct thread *td; 798 799 PROC_LOCK_ASSERT(p, MA_OWNED); 800 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 801 #if defined(SWAP_DEBUG) 802 printf("swapping out %d\n", p->p_pid); 803 #endif 804 805 /* 806 * The states of this process and its threads may have changed 807 * by now. Assuming that there is only one pageout daemon thread, 808 * this process should still be in memory. 809 */ 810 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) == PS_INMEM, 811 ("swapout: lost a swapout race?")); 812 813 #if defined(INVARIANTS) 814 /* 815 * Make sure that all threads are safe to be swapped out. 816 * 817 * Alternatively, we could swap out only safe threads. 818 */ 819 FOREACH_THREAD_IN_PROC(p, td) { 820 KASSERT(thread_safetoswapout(td), 821 ("swapout: there is a thread not safe for swapout")); 822 } 823 #endif /* INVARIANTS */ 824 825 ++p->p_stats->p_ru.ru_nswap; 826 /* 827 * remember the process resident count 828 */ 829 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 830 831 PROC_UNLOCK(p); 832 FOREACH_THREAD_IN_PROC (p, td) 833 if (td->td_state == TDS_RUNQ) { /* XXXKSE */ 834 remrunqueue(td); /* XXXKSE */ 835 td->td_state = TDS_SWAPPED; 836 } 837 p->p_sflag &= ~PS_INMEM; 838 p->p_sflag |= PS_SWAPPING; 839 mtx_unlock_spin(&sched_lock); 840 841 vm_proc_swapout(p); 842 FOREACH_THREAD_IN_PROC(p, td) 843 pmap_swapout_thread(td); 844 mtx_lock_spin(&sched_lock); 845 p->p_sflag &= ~PS_SWAPPING; 846 p->p_swtime = 0; 847 } 848 #endif /* !NO_SWAPPING */ 849