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 #include <vm/swap_pager.h> 95 96 #include <sys/user.h> 97 98 extern int maxslp; 99 100 /* 101 * System initialization 102 * 103 * Note: proc0 from proc.h 104 */ 105 static void vm_init_limits(void *); 106 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 107 108 /* 109 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 110 * 111 * Note: run scheduling should be divorced from the vm system. 112 */ 113 static void scheduler(void *); 114 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 115 116 #ifndef NO_SWAPPING 117 static void swapout(struct proc *); 118 static void vm_proc_swapin(struct proc *p); 119 static void vm_proc_swapout(struct proc *p); 120 #endif 121 122 /* 123 * MPSAFE 124 * 125 * WARNING! This code calls vm_map_check_protection() which only checks 126 * the associated vm_map_entry range. It does not determine whether the 127 * contents of the memory is actually readable or writable. In most cases 128 * just checking the vm_map_entry is sufficient within the kernel's address 129 * space. 130 */ 131 int 132 kernacc(addr, len, rw) 133 void *addr; 134 int len, rw; 135 { 136 boolean_t rv; 137 vm_offset_t saddr, eaddr; 138 vm_prot_t prot; 139 140 KASSERT((rw & ~VM_PROT_ALL) == 0, 141 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 142 prot = rw; 143 saddr = trunc_page((vm_offset_t)addr); 144 eaddr = round_page((vm_offset_t)addr + len); 145 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 146 return (rv == TRUE); 147 } 148 149 /* 150 * MPSAFE 151 * 152 * WARNING! This code calls vm_map_check_protection() which only checks 153 * the associated vm_map_entry range. It does not determine whether the 154 * contents of the memory is actually readable or writable. vmapbuf(), 155 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be 156 * used in conjuction with this call. 157 */ 158 int 159 useracc(addr, len, rw) 160 void *addr; 161 int len, rw; 162 { 163 boolean_t rv; 164 vm_prot_t prot; 165 vm_map_t map; 166 167 KASSERT((rw & ~VM_PROT_ALL) == 0, 168 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 169 prot = rw; 170 map = &curproc->p_vmspace->vm_map; 171 if ((vm_offset_t)addr + len > vm_map_max(map) || 172 (vm_offset_t)addr + len < (vm_offset_t)addr) { 173 return (FALSE); 174 } 175 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 176 round_page((vm_offset_t)addr + len), prot); 177 return (rv == TRUE); 178 } 179 180 /* 181 * MPSAFE 182 */ 183 void 184 vslock(addr, len) 185 void *addr; 186 u_int len; 187 { 188 189 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 190 round_page((vm_offset_t)addr + len), FALSE); 191 } 192 193 /* 194 * MPSAFE 195 */ 196 void 197 vsunlock(addr, len) 198 void *addr; 199 u_int len; 200 { 201 202 vm_map_unwire(&curproc->p_vmspace->vm_map, 203 trunc_page((vm_offset_t)addr), 204 round_page((vm_offset_t)addr + len), FALSE); 205 } 206 207 /* 208 * Create the U area for a new process. 209 * This routine directly affects the fork perf for a process. 210 */ 211 void 212 vm_proc_new(struct proc *p) 213 { 214 vm_page_t ma[UAREA_PAGES]; 215 vm_object_t upobj; 216 vm_offset_t up; 217 vm_page_t m; 218 u_int i; 219 220 /* 221 * Allocate object for the upage. 222 */ 223 upobj = vm_object_allocate(OBJT_DEFAULT, UAREA_PAGES); 224 p->p_upages_obj = upobj; 225 226 /* 227 * Get a kernel virtual address for the U area for this process. 228 */ 229 up = kmem_alloc_nofault(kernel_map, UAREA_PAGES * PAGE_SIZE); 230 if (up == 0) 231 panic("vm_proc_new: upage allocation failed"); 232 p->p_uarea = (struct user *)up; 233 234 for (i = 0; i < UAREA_PAGES; i++) { 235 /* 236 * Get a uarea page. 237 */ 238 m = vm_page_grab(upobj, i, 239 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 240 ma[i] = m; 241 242 vm_page_lock_queues(); 243 vm_page_wakeup(m); 244 vm_page_flag_clear(m, PG_ZERO); 245 m->valid = VM_PAGE_BITS_ALL; 246 vm_page_unlock_queues(); 247 } 248 249 /* 250 * Enter the pages into the kernel address space. 251 */ 252 pmap_qenter(up, ma, UAREA_PAGES); 253 } 254 255 /* 256 * Dispose the U area for a process that has exited. 257 * This routine directly impacts the exit perf of a process. 258 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 259 */ 260 void 261 vm_proc_dispose(struct proc *p) 262 { 263 vm_object_t upobj; 264 vm_offset_t up; 265 vm_page_t m; 266 267 upobj = p->p_upages_obj; 268 if (upobj->resident_page_count != UAREA_PAGES) 269 panic("vm_proc_dispose: incorrect number of pages in upobj"); 270 vm_page_lock_queues(); 271 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 272 vm_page_busy(m); 273 vm_page_unwire(m, 0); 274 vm_page_free(m); 275 } 276 vm_page_unlock_queues(); 277 up = (vm_offset_t)p->p_uarea; 278 pmap_qremove(up, UAREA_PAGES); 279 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 280 vm_object_deallocate(upobj); 281 } 282 283 #ifndef NO_SWAPPING 284 /* 285 * Allow the U area for a process to be prejudicially paged out. 286 */ 287 static void 288 vm_proc_swapout(struct proc *p) 289 { 290 vm_object_t upobj; 291 vm_offset_t up; 292 vm_page_t m; 293 294 upobj = p->p_upages_obj; 295 if (upobj->resident_page_count != UAREA_PAGES) 296 panic("vm_proc_dispose: incorrect number of pages in upobj"); 297 vm_page_lock_queues(); 298 TAILQ_FOREACH(m, &upobj->memq, listq) { 299 vm_page_dirty(m); 300 vm_page_unwire(m, 0); 301 } 302 vm_page_unlock_queues(); 303 up = (vm_offset_t)p->p_uarea; 304 pmap_qremove(up, UAREA_PAGES); 305 } 306 307 /* 308 * Bring the U area for a specified process back in. 309 */ 310 static void 311 vm_proc_swapin(struct proc *p) 312 { 313 vm_page_t ma[UAREA_PAGES]; 314 vm_object_t upobj; 315 vm_offset_t up; 316 vm_page_t m; 317 int rv; 318 int i; 319 320 upobj = p->p_upages_obj; 321 for (i = 0; i < UAREA_PAGES; i++) { 322 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 323 if (m->valid != VM_PAGE_BITS_ALL) { 324 rv = vm_pager_get_pages(upobj, &m, 1, 0); 325 if (rv != VM_PAGER_OK) 326 panic("vm_proc_swapin: cannot get upage"); 327 } 328 ma[i] = m; 329 } 330 if (upobj->resident_page_count != UAREA_PAGES) 331 panic("vm_proc_swapin: lost pages from upobj"); 332 vm_page_lock_queues(); 333 TAILQ_FOREACH(m, &upobj->memq, listq) { 334 m->valid = VM_PAGE_BITS_ALL; 335 vm_page_wire(m); 336 vm_page_wakeup(m); 337 } 338 vm_page_unlock_queues(); 339 up = (vm_offset_t)p->p_uarea; 340 pmap_qenter(up, ma, UAREA_PAGES); 341 } 342 343 /* 344 * Swap in the UAREAs of all processes swapped out to the given device. 345 * The pages in the UAREA are marked dirty and their swap metadata is freed. 346 */ 347 void 348 vm_proc_swapin_all(int devidx) 349 { 350 struct proc *p; 351 vm_object_t object; 352 vm_page_t m; 353 354 retry: 355 sx_slock(&allproc_lock); 356 FOREACH_PROC_IN_SYSTEM(p) { 357 PROC_LOCK(p); 358 mtx_lock_spin(&sched_lock); 359 360 object = p->p_upages_obj; 361 if (object != NULL && 362 swap_pager_isswapped(p->p_upages_obj, devidx)) { 363 sx_sunlock(&allproc_lock); 364 faultin(p); 365 mtx_unlock_spin(&sched_lock); 366 PROC_UNLOCK(p); 367 vm_page_lock_queues(); 368 TAILQ_FOREACH(m, &object->memq, listq) 369 vm_page_dirty(m); 370 vm_page_unlock_queues(); 371 swap_pager_freespace(object, 0, 372 object->un_pager.swp.swp_bcount); 373 goto retry; 374 } 375 376 mtx_unlock_spin(&sched_lock); 377 PROC_UNLOCK(p); 378 } 379 sx_sunlock(&allproc_lock); 380 } 381 #endif 382 383 /* 384 * Implement fork's actions on an address space. 385 * Here we arrange for the address space to be copied or referenced, 386 * allocate a user struct (pcb and kernel stack), then call the 387 * machine-dependent layer to fill those in and make the new process 388 * ready to run. The new process is set up so that it returns directly 389 * to user mode to avoid stack copying and relocation problems. 390 */ 391 void 392 vm_forkproc(td, p2, td2, flags) 393 struct thread *td; 394 struct proc *p2; 395 struct thread *td2; 396 int flags; 397 { 398 struct proc *p1 = td->td_proc; 399 struct user *up; 400 401 GIANT_REQUIRED; 402 403 if ((flags & RFPROC) == 0) { 404 /* 405 * Divorce the memory, if it is shared, essentially 406 * this changes shared memory amongst threads, into 407 * COW locally. 408 */ 409 if ((flags & RFMEM) == 0) { 410 if (p1->p_vmspace->vm_refcnt > 1) { 411 vmspace_unshare(p1); 412 } 413 } 414 cpu_fork(td, p2, td2, flags); 415 return; 416 } 417 418 if (flags & RFMEM) { 419 p2->p_vmspace = p1->p_vmspace; 420 p1->p_vmspace->vm_refcnt++; 421 } 422 423 while (vm_page_count_severe()) { 424 VM_WAIT; 425 } 426 427 if ((flags & RFMEM) == 0) { 428 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 429 430 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 431 432 if (p1->p_vmspace->vm_shm) 433 shmfork(p1, p2); 434 } 435 436 /* XXXKSE this is unsatisfactory but should be adequate */ 437 up = p2->p_uarea; 438 439 /* 440 * p_stats currently points at fields in the user struct 441 * but not at &u, instead at p_addr. Copy parts of 442 * p_stats; zero the rest of p_stats (statistics). 443 * 444 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 445 * to share sigacts, so we use the up->u_sigacts. 446 */ 447 p2->p_stats = &up->u_stats; 448 if (p2->p_sigacts == NULL) { 449 if (p2->p_procsig->ps_refcnt != 1) 450 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 451 p2->p_sigacts = &up->u_sigacts; 452 up->u_sigacts = *p1->p_sigacts; 453 } 454 455 bzero(&up->u_stats.pstat_startzero, 456 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 457 (caddr_t) &up->u_stats.pstat_startzero)); 458 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 459 ((caddr_t) &up->u_stats.pstat_endcopy - 460 (caddr_t) &up->u_stats.pstat_startcopy)); 461 462 463 /* 464 * cpu_fork will copy and update the pcb, set up the kernel stack, 465 * and make the child ready to run. 466 */ 467 cpu_fork(td, p2, td2, flags); 468 } 469 470 /* 471 * Called after process has been wait(2)'ed apon and is being reaped. 472 * The idea is to reclaim resources that we could not reclaim while 473 * the process was still executing. 474 */ 475 void 476 vm_waitproc(p) 477 struct proc *p; 478 { 479 480 GIANT_REQUIRED; 481 cpu_wait(p); 482 vmspace_exitfree(p); /* and clean-out the vmspace */ 483 } 484 485 /* 486 * Set default limits for VM system. 487 * Called for proc 0, and then inherited by all others. 488 * 489 * XXX should probably act directly on proc0. 490 */ 491 static void 492 vm_init_limits(udata) 493 void *udata; 494 { 495 struct proc *p = udata; 496 int rss_limit; 497 498 /* 499 * Set up the initial limits on process VM. Set the maximum resident 500 * set size to be half of (reasonably) available memory. Since this 501 * is a soft limit, it comes into effect only when the system is out 502 * of memory - half of main memory helps to favor smaller processes, 503 * and reduces thrashing of the object cache. 504 */ 505 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 506 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 507 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 508 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 509 /* limit the limit to no less than 2MB */ 510 rss_limit = max(cnt.v_free_count, 512); 511 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 512 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 513 } 514 515 void 516 faultin(p) 517 struct proc *p; 518 { 519 520 GIANT_REQUIRED; 521 PROC_LOCK_ASSERT(p, MA_OWNED); 522 mtx_assert(&sched_lock, MA_OWNED); 523 #ifdef NO_SWAPPING 524 if ((p->p_sflag & PS_INMEM) == 0) 525 panic("faultin: proc swapped out with NO_SWAPPING!"); 526 #else 527 if ((p->p_sflag & PS_INMEM) == 0) { 528 struct thread *td; 529 530 ++p->p_lock; 531 /* 532 * If another process is swapping in this process, 533 * just wait until it finishes. 534 */ 535 if (p->p_sflag & PS_SWAPPINGIN) { 536 mtx_unlock_spin(&sched_lock); 537 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 538 mtx_lock_spin(&sched_lock); 539 --p->p_lock; 540 return; 541 } 542 543 p->p_sflag |= PS_SWAPPINGIN; 544 mtx_unlock_spin(&sched_lock); 545 PROC_UNLOCK(p); 546 547 vm_proc_swapin(p); 548 FOREACH_THREAD_IN_PROC (p, td) { 549 pmap_swapin_thread(td); 550 TD_CLR_SWAPPED(td); 551 } 552 553 PROC_LOCK(p); 554 mtx_lock_spin(&sched_lock); 555 p->p_sflag &= ~PS_SWAPPINGIN; 556 p->p_sflag |= PS_INMEM; 557 FOREACH_THREAD_IN_PROC (p, td) 558 if (TD_CAN_RUN(td)) 559 setrunnable(td); 560 561 wakeup(&p->p_sflag); 562 563 /* undo the effect of setting SLOCK above */ 564 --p->p_lock; 565 } 566 #endif 567 } 568 569 /* 570 * This swapin algorithm attempts to swap-in processes only if there 571 * is enough space for them. Of course, if a process waits for a long 572 * time, it will be swapped in anyway. 573 * 574 * XXXKSE - process with the thread with highest priority counts.. 575 * 576 * Giant is still held at this point, to be released in tsleep. 577 */ 578 /* ARGSUSED*/ 579 static void 580 scheduler(dummy) 581 void *dummy; 582 { 583 struct proc *p; 584 struct thread *td; 585 int pri; 586 struct proc *pp; 587 int ppri; 588 589 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 590 /* GIANT_REQUIRED */ 591 592 loop: 593 if (vm_page_count_min()) { 594 VM_WAIT; 595 goto loop; 596 } 597 598 pp = NULL; 599 ppri = INT_MIN; 600 sx_slock(&allproc_lock); 601 FOREACH_PROC_IN_SYSTEM(p) { 602 struct ksegrp *kg; 603 if (p->p_sflag & (PS_INMEM | PS_SWAPPING | PS_SWAPPINGIN)) { 604 continue; 605 } 606 mtx_lock_spin(&sched_lock); 607 FOREACH_THREAD_IN_PROC(p, td) { 608 /* 609 * An otherwise runnable thread of a process 610 * swapped out has only the TDI_SWAPPED bit set. 611 * 612 */ 613 if (td->td_inhibitors == TDI_SWAPPED) { 614 kg = td->td_ksegrp; 615 pri = p->p_swtime + kg->kg_slptime; 616 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 617 pri -= kg->kg_nice * 8; 618 } 619 620 /* 621 * if this ksegrp is higher priority 622 * and there is enough space, then select 623 * this process instead of the previous 624 * selection. 625 */ 626 if (pri > ppri) { 627 pp = p; 628 ppri = pri; 629 } 630 } 631 } 632 mtx_unlock_spin(&sched_lock); 633 } 634 sx_sunlock(&allproc_lock); 635 636 /* 637 * Nothing to do, back to sleep. 638 */ 639 if ((p = pp) == NULL) { 640 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 641 goto loop; 642 } 643 PROC_LOCK(p); 644 mtx_lock_spin(&sched_lock); 645 646 /* 647 * Another process may be bringing or may have already 648 * brought this process in while we traverse all threads. 649 * Or, this process may even be being swapped out again. 650 */ 651 if (p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) { 652 mtx_unlock_spin(&sched_lock); 653 PROC_UNLOCK(p); 654 goto loop; 655 } 656 657 p->p_sflag &= ~PS_SWAPINREQ; 658 659 /* 660 * We would like to bring someone in. (only if there is space). 661 * [What checks the space? ] 662 */ 663 faultin(p); 664 PROC_UNLOCK(p); 665 p->p_swtime = 0; 666 mtx_unlock_spin(&sched_lock); 667 goto loop; 668 } 669 670 #ifndef NO_SWAPPING 671 672 /* 673 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 674 */ 675 static int swap_idle_threshold1 = 2; 676 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 677 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 678 679 /* 680 * Swap_idle_threshold2 is the time that a process can be idle before 681 * it will be swapped out, if idle swapping is enabled. 682 */ 683 static int swap_idle_threshold2 = 10; 684 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 685 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 686 687 /* 688 * Swapout is driven by the pageout daemon. Very simple, we find eligible 689 * procs and unwire their u-areas. We try to always "swap" at least one 690 * process in case we need the room for a swapin. 691 * If any procs have been sleeping/stopped for at least maxslp seconds, 692 * they are swapped. Else, we swap the longest-sleeping or stopped process, 693 * if any, otherwise the longest-resident process. 694 */ 695 void 696 swapout_procs(action) 697 int action; 698 { 699 struct proc *p; 700 struct thread *td; 701 struct ksegrp *kg; 702 struct proc *outp, *outp2; 703 int outpri, outpri2; 704 int didswap = 0; 705 706 GIANT_REQUIRED; 707 708 outp = outp2 = NULL; 709 outpri = outpri2 = INT_MIN; 710 retry: 711 sx_slock(&allproc_lock); 712 FOREACH_PROC_IN_SYSTEM(p) { 713 struct vmspace *vm; 714 int minslptime = 100000; 715 716 /* 717 * Watch out for a process in 718 * creation. It may have no 719 * address space or lock yet. 720 */ 721 mtx_lock_spin(&sched_lock); 722 if (p->p_state == PRS_NEW) { 723 mtx_unlock_spin(&sched_lock); 724 continue; 725 } 726 mtx_unlock_spin(&sched_lock); 727 728 /* 729 * An aio daemon switches its 730 * address space while running. 731 * Perform a quick check whether 732 * a process has P_SYSTEM. 733 */ 734 PROC_LOCK(p); 735 if ((p->p_flag & P_SYSTEM) != 0) { 736 PROC_UNLOCK(p); 737 continue; 738 } 739 740 /* 741 * Do not swapout a process that 742 * is waiting for VM data 743 * structures as there is a possible 744 * deadlock. Test this first as 745 * this may block. 746 * 747 * Lock the map until swapout 748 * finishes, or a thread of this 749 * process may attempt to alter 750 * the map. 751 */ 752 vm = p->p_vmspace; 753 KASSERT(vm != NULL, 754 ("swapout_procs: a process has no address space")); 755 ++vm->vm_refcnt; 756 PROC_UNLOCK(p); 757 if (!vm_map_trylock(&vm->vm_map)) 758 goto nextproc1; 759 760 PROC_LOCK(p); 761 if (p->p_lock != 0 || 762 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) 763 ) != 0) { 764 goto nextproc2; 765 } 766 /* 767 * only aiod changes vmspace, however it will be 768 * skipped because of the if statement above checking 769 * for P_SYSTEM 770 */ 771 mtx_lock_spin(&sched_lock); 772 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) != PS_INMEM) 773 goto nextproc; 774 775 switch (p->p_state) { 776 default: 777 /* Don't swap out processes in any sort 778 * of 'special' state. */ 779 goto nextproc; 780 781 case PRS_NORMAL: 782 /* 783 * do not swapout a realtime process 784 * Check all the thread groups.. 785 */ 786 FOREACH_KSEGRP_IN_PROC(p, kg) { 787 if (PRI_IS_REALTIME(kg->kg_pri_class)) 788 goto nextproc; 789 790 /* 791 * Guarantee swap_idle_threshold1 792 * time in memory. 793 */ 794 if (kg->kg_slptime < swap_idle_threshold1) 795 goto nextproc; 796 797 /* 798 * Do not swapout a process if it is 799 * waiting on a critical event of some 800 * kind or there is a thread whose 801 * pageable memory may be accessed. 802 * 803 * This could be refined to support 804 * swapping out a thread. 805 */ 806 FOREACH_THREAD_IN_GROUP(kg, td) { 807 if ((td->td_priority) < PSOCK || 808 !thread_safetoswapout(td)) 809 goto nextproc; 810 } 811 /* 812 * If the system is under memory stress, 813 * or if we are swapping 814 * idle processes >= swap_idle_threshold2, 815 * then swap the process out. 816 */ 817 if (((action & VM_SWAP_NORMAL) == 0) && 818 (((action & VM_SWAP_IDLE) == 0) || 819 (kg->kg_slptime < swap_idle_threshold2))) 820 goto nextproc; 821 822 if (minslptime > kg->kg_slptime) 823 minslptime = kg->kg_slptime; 824 } 825 826 /* 827 * If the process has been asleep for awhile and had 828 * most of its pages taken away already, swap it out. 829 */ 830 if ((action & VM_SWAP_NORMAL) || 831 ((action & VM_SWAP_IDLE) && 832 (minslptime > swap_idle_threshold2))) { 833 swapout(p); 834 didswap++; 835 836 /* 837 * swapout() unlocks a proc lock. This is 838 * ugly, but avoids superfluous lock. 839 */ 840 mtx_unlock_spin(&sched_lock); 841 vm_map_unlock(&vm->vm_map); 842 vmspace_free(vm); 843 sx_sunlock(&allproc_lock); 844 goto retry; 845 } 846 } 847 nextproc: 848 mtx_unlock_spin(&sched_lock); 849 nextproc2: 850 PROC_UNLOCK(p); 851 vm_map_unlock(&vm->vm_map); 852 nextproc1: 853 vmspace_free(vm); 854 continue; 855 } 856 sx_sunlock(&allproc_lock); 857 /* 858 * If we swapped something out, and another process needed memory, 859 * then wakeup the sched process. 860 */ 861 if (didswap) 862 wakeup(&proc0); 863 } 864 865 static void 866 swapout(p) 867 struct proc *p; 868 { 869 struct thread *td; 870 871 PROC_LOCK_ASSERT(p, MA_OWNED); 872 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 873 #if defined(SWAP_DEBUG) 874 printf("swapping out %d\n", p->p_pid); 875 #endif 876 877 /* 878 * The states of this process and its threads may have changed 879 * by now. Assuming that there is only one pageout daemon thread, 880 * this process should still be in memory. 881 */ 882 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) == PS_INMEM, 883 ("swapout: lost a swapout race?")); 884 885 #if defined(INVARIANTS) 886 /* 887 * Make sure that all threads are safe to be swapped out. 888 * 889 * Alternatively, we could swap out only safe threads. 890 */ 891 FOREACH_THREAD_IN_PROC(p, td) { 892 KASSERT(thread_safetoswapout(td), 893 ("swapout: there is a thread not safe for swapout")); 894 } 895 #endif /* INVARIANTS */ 896 897 ++p->p_stats->p_ru.ru_nswap; 898 /* 899 * remember the process resident count 900 */ 901 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 902 903 PROC_UNLOCK(p); 904 p->p_sflag &= ~PS_INMEM; 905 p->p_sflag |= PS_SWAPPING; 906 mtx_unlock_spin(&sched_lock); 907 908 vm_proc_swapout(p); 909 FOREACH_THREAD_IN_PROC(p, td) { 910 pmap_swapout_thread(td); 911 TD_SET_SWAPPED(td); 912 } 913 mtx_lock_spin(&sched_lock); 914 p->p_sflag &= ~PS_SWAPPING; 915 p->p_swtime = 0; 916 } 917 #endif /* !NO_SWAPPING */ 918