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, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 234 ma[i] = m; 235 236 /* 237 * Wire the page. 238 */ 239 m->wire_count++; 240 cnt.v_wire_count++; 241 242 vm_page_wakeup(m); 243 vm_page_flag_clear(m, PG_ZERO); 244 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE); 245 m->valid = VM_PAGE_BITS_ALL; 246 } 247 248 /* 249 * Enter the pages into the kernel address space. 250 */ 251 pmap_qenter(up, ma, UAREA_PAGES); 252 } 253 254 /* 255 * Dispose the U area for a process that has exited. 256 * This routine directly impacts the exit perf of a process. 257 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 258 */ 259 void 260 vm_proc_dispose(struct proc *p) 261 { 262 vm_object_t upobj; 263 vm_offset_t up; 264 vm_page_t m; 265 266 upobj = p->p_upages_obj; 267 if (upobj->resident_page_count != UAREA_PAGES) 268 panic("vm_proc_dispose: incorrect number of pages in upobj"); 269 vm_page_lock_queues(); 270 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 271 vm_page_busy(m); 272 vm_page_unwire(m, 0); 273 vm_page_free(m); 274 } 275 vm_page_unlock_queues(); 276 up = (vm_offset_t)p->p_uarea; 277 pmap_qremove(up, UAREA_PAGES); 278 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 279 vm_object_deallocate(upobj); 280 } 281 282 #ifndef NO_SWAPPING 283 /* 284 * Allow the U area for a process to be prejudicially paged out. 285 */ 286 void 287 vm_proc_swapout(struct proc *p) 288 { 289 vm_object_t upobj; 290 vm_offset_t up; 291 vm_page_t m; 292 293 upobj = p->p_upages_obj; 294 if (upobj->resident_page_count != UAREA_PAGES) 295 panic("vm_proc_dispose: incorrect number of pages in upobj"); 296 vm_page_lock_queues(); 297 TAILQ_FOREACH(m, &upobj->memq, listq) { 298 vm_page_dirty(m); 299 vm_page_unwire(m, 0); 300 } 301 vm_page_unlock_queues(); 302 up = (vm_offset_t)p->p_uarea; 303 pmap_qremove(up, UAREA_PAGES); 304 } 305 306 /* 307 * Bring the U area for a specified process back in. 308 */ 309 void 310 vm_proc_swapin(struct proc *p) 311 { 312 vm_page_t ma[UAREA_PAGES]; 313 vm_object_t upobj; 314 vm_offset_t up; 315 vm_page_t m; 316 int rv; 317 int i; 318 319 upobj = p->p_upages_obj; 320 for (i = 0; i < UAREA_PAGES; i++) { 321 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 322 if (m->valid != VM_PAGE_BITS_ALL) { 323 rv = vm_pager_get_pages(upobj, &m, 1, 0); 324 if (rv != VM_PAGER_OK) 325 panic("vm_proc_swapin: cannot get upage"); 326 } 327 ma[i] = m; 328 } 329 if (upobj->resident_page_count != UAREA_PAGES) 330 panic("vm_proc_swapin: lost pages from upobj"); 331 vm_page_lock_queues(); 332 TAILQ_FOREACH(m, &upobj->memq, listq) { 333 m->valid = VM_PAGE_BITS_ALL; 334 vm_page_wire(m); 335 vm_page_wakeup(m); 336 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE); 337 } 338 vm_page_unlock_queues(); 339 up = (vm_offset_t)p->p_uarea; 340 pmap_qenter(up, ma, UAREA_PAGES); 341 } 342 #endif 343 344 /* 345 * Implement fork's actions on an address space. 346 * Here we arrange for the address space to be copied or referenced, 347 * allocate a user struct (pcb and kernel stack), then call the 348 * machine-dependent layer to fill those in and make the new process 349 * ready to run. The new process is set up so that it returns directly 350 * to user mode to avoid stack copying and relocation problems. 351 */ 352 void 353 vm_forkproc(td, p2, td2, flags) 354 struct thread *td; 355 struct proc *p2; 356 struct thread *td2; 357 int flags; 358 { 359 struct proc *p1 = td->td_proc; 360 struct user *up; 361 362 GIANT_REQUIRED; 363 364 if ((flags & RFPROC) == 0) { 365 /* 366 * Divorce the memory, if it is shared, essentially 367 * this changes shared memory amongst threads, into 368 * COW locally. 369 */ 370 if ((flags & RFMEM) == 0) { 371 if (p1->p_vmspace->vm_refcnt > 1) { 372 vmspace_unshare(p1); 373 } 374 } 375 cpu_fork(td, p2, td2, flags); 376 return; 377 } 378 379 if (flags & RFMEM) { 380 p2->p_vmspace = p1->p_vmspace; 381 p1->p_vmspace->vm_refcnt++; 382 } 383 384 while (vm_page_count_severe()) { 385 VM_WAIT; 386 } 387 388 if ((flags & RFMEM) == 0) { 389 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 390 391 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 392 393 if (p1->p_vmspace->vm_shm) 394 shmfork(p1, p2); 395 } 396 397 /* XXXKSE this is unsatisfactory but should be adequate */ 398 up = p2->p_uarea; 399 400 /* 401 * p_stats currently points at fields in the user struct 402 * but not at &u, instead at p_addr. Copy parts of 403 * p_stats; zero the rest of p_stats (statistics). 404 * 405 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 406 * to share sigacts, so we use the up->u_sigacts. 407 */ 408 p2->p_stats = &up->u_stats; 409 if (p2->p_sigacts == NULL) { 410 if (p2->p_procsig->ps_refcnt != 1) 411 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 412 p2->p_sigacts = &up->u_sigacts; 413 up->u_sigacts = *p1->p_sigacts; 414 } 415 416 bzero(&up->u_stats.pstat_startzero, 417 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 418 (caddr_t) &up->u_stats.pstat_startzero)); 419 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 420 ((caddr_t) &up->u_stats.pstat_endcopy - 421 (caddr_t) &up->u_stats.pstat_startcopy)); 422 423 424 /* 425 * cpu_fork will copy and update the pcb, set up the kernel stack, 426 * and make the child ready to run. 427 */ 428 cpu_fork(td, p2, td2, flags); 429 } 430 431 /* 432 * Called after process has been wait(2)'ed apon and is being reaped. 433 * The idea is to reclaim resources that we could not reclaim while 434 * the process was still executing. 435 */ 436 void 437 vm_waitproc(p) 438 struct proc *p; 439 { 440 struct thread *td; 441 442 GIANT_REQUIRED; 443 cpu_wait(p); 444 /* XXXKSE by here there should not be any threads left! */ 445 FOREACH_THREAD_IN_PROC(p, td) { 446 panic("vm_waitproc: Survivor thread!"); 447 } 448 vmspace_exitfree(p); /* and clean-out the vmspace */ 449 } 450 451 /* 452 * Set default limits for VM system. 453 * Called for proc 0, and then inherited by all others. 454 * 455 * XXX should probably act directly on proc0. 456 */ 457 static void 458 vm_init_limits(udata) 459 void *udata; 460 { 461 struct proc *p = udata; 462 int rss_limit; 463 464 /* 465 * Set up the initial limits on process VM. Set the maximum resident 466 * set size to be half of (reasonably) available memory. Since this 467 * is a soft limit, it comes into effect only when the system is out 468 * of memory - half of main memory helps to favor smaller processes, 469 * and reduces thrashing of the object cache. 470 */ 471 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 472 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 473 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 474 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 475 /* limit the limit to no less than 2MB */ 476 rss_limit = max(cnt.v_free_count, 512); 477 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 478 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 479 } 480 481 void 482 faultin(p) 483 struct proc *p; 484 { 485 486 GIANT_REQUIRED; 487 PROC_LOCK_ASSERT(p, MA_OWNED); 488 mtx_lock_spin(&sched_lock); 489 #ifdef NO_SWAPPING 490 if ((p->p_sflag & PS_INMEM) == 0) 491 panic("faultin: proc swapped out with NO_SWAPPING!"); 492 #else 493 if ((p->p_sflag & PS_INMEM) == 0) { 494 struct thread *td; 495 496 ++p->p_lock; 497 mtx_unlock_spin(&sched_lock); 498 PROC_UNLOCK(p); 499 500 vm_proc_swapin(p); 501 FOREACH_THREAD_IN_PROC (p, td) 502 pmap_swapin_thread(td); 503 504 PROC_LOCK(p); 505 mtx_lock_spin(&sched_lock); 506 FOREACH_THREAD_IN_PROC (p, td) 507 if (td->td_state == TDS_RUNQ) /* XXXKSE */ 508 setrunqueue(td); 509 510 p->p_sflag |= PS_INMEM; 511 512 /* undo the effect of setting SLOCK above */ 513 --p->p_lock; 514 } 515 #endif 516 mtx_unlock_spin(&sched_lock); 517 } 518 519 /* 520 * This swapin algorithm attempts to swap-in processes only if there 521 * is enough space for them. Of course, if a process waits for a long 522 * time, it will be swapped in anyway. 523 * 524 * XXXKSE - process with the thread with highest priority counts.. 525 * 526 * Giant is still held at this point, to be released in tsleep. 527 */ 528 /* ARGSUSED*/ 529 static void 530 scheduler(dummy) 531 void *dummy; 532 { 533 struct proc *p; 534 struct thread *td; 535 int pri; 536 struct proc *pp; 537 int ppri; 538 539 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 540 /* GIANT_REQUIRED */ 541 542 loop: 543 if (vm_page_count_min()) { 544 VM_WAIT; 545 goto loop; 546 } 547 548 pp = NULL; 549 ppri = INT_MIN; 550 sx_slock(&allproc_lock); 551 FOREACH_PROC_IN_SYSTEM(p) { 552 struct ksegrp *kg; 553 if (p->p_sflag & (PS_INMEM | PS_SWAPPING)) { 554 continue; 555 } 556 mtx_lock_spin(&sched_lock); 557 FOREACH_THREAD_IN_PROC(p, td) { 558 /* Only consider runnable threads */ 559 if (td->td_state == TDS_RUNQ) { 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 mtx_lock_spin(&sched_lock); 590 p->p_sflag &= ~PS_SWAPINREQ; 591 mtx_unlock_spin(&sched_lock); 592 593 /* 594 * We would like to bring someone in. (only if there is space). 595 * [What checks the space? ] 596 */ 597 PROC_LOCK(p); 598 faultin(p); 599 PROC_UNLOCK(p); 600 mtx_lock_spin(&sched_lock); 601 p->p_swtime = 0; 602 mtx_unlock_spin(&sched_lock); 603 goto loop; 604 } 605 606 #ifndef NO_SWAPPING 607 608 /* 609 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 610 */ 611 static int swap_idle_threshold1 = 2; 612 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 613 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 614 615 /* 616 * Swap_idle_threshold2 is the time that a process can be idle before 617 * it will be swapped out, if idle swapping is enabled. 618 */ 619 static int swap_idle_threshold2 = 10; 620 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 621 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 622 623 /* 624 * Swapout is driven by the pageout daemon. Very simple, we find eligible 625 * procs and unwire their u-areas. We try to always "swap" at least one 626 * process in case we need the room for a swapin. 627 * If any procs have been sleeping/stopped for at least maxslp seconds, 628 * they are swapped. Else, we swap the longest-sleeping or stopped process, 629 * if any, otherwise the longest-resident process. 630 */ 631 void 632 swapout_procs(action) 633 int action; 634 { 635 struct proc *p; 636 struct thread *td; 637 struct ksegrp *kg; 638 struct proc *outp, *outp2; 639 int outpri, outpri2; 640 int didswap = 0; 641 642 GIANT_REQUIRED; 643 644 outp = outp2 = NULL; 645 outpri = outpri2 = INT_MIN; 646 retry: 647 sx_slock(&allproc_lock); 648 FOREACH_PROC_IN_SYSTEM(p) { 649 struct vmspace *vm; 650 int minslptime = 100000; 651 652 PROC_LOCK(p); 653 if (p->p_lock != 0 || 654 (p->p_flag & (P_STOPPED_SNGL|P_TRACED|P_SYSTEM|P_WEXIT)) != 0) { 655 PROC_UNLOCK(p); 656 continue; 657 } 658 /* 659 * only aiod changes vmspace, however it will be 660 * skipped because of the if statement above checking 661 * for P_SYSTEM 662 */ 663 vm = p->p_vmspace; 664 mtx_lock_spin(&sched_lock); 665 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING)) != PS_INMEM) { 666 mtx_unlock_spin(&sched_lock); 667 PROC_UNLOCK(p); 668 continue; 669 } 670 671 switch (p->p_state) { 672 default: 673 /* Don't swap out processes in any sort 674 * of 'special' state. */ 675 mtx_unlock_spin(&sched_lock); 676 PROC_UNLOCK(p); 677 continue; 678 679 case PRS_NORMAL: 680 /* 681 * do not swapout a realtime process 682 * Check all the thread groups.. 683 */ 684 FOREACH_KSEGRP_IN_PROC(p, kg) { 685 if (PRI_IS_REALTIME(kg->kg_pri_class)) { 686 mtx_unlock_spin(&sched_lock); 687 PROC_UNLOCK(p); 688 goto nextproc; 689 } 690 691 /* 692 * Do not swapout a process waiting 693 * on a critical event of some kind. 694 * Also guarantee swap_idle_threshold1 695 * time in memory. 696 */ 697 if (kg->kg_slptime < swap_idle_threshold1) { 698 mtx_unlock_spin(&sched_lock); 699 PROC_UNLOCK(p); 700 goto nextproc; 701 } 702 FOREACH_THREAD_IN_PROC(p, td) { 703 if ((td->td_priority) < PSOCK) { 704 mtx_unlock_spin(&sched_lock); 705 PROC_UNLOCK(p); 706 goto nextproc; 707 } 708 } 709 /* 710 * If the system is under memory stress, 711 * or if we are swapping 712 * idle processes >= swap_idle_threshold2, 713 * then swap the process out. 714 */ 715 if (((action & VM_SWAP_NORMAL) == 0) && 716 (((action & VM_SWAP_IDLE) == 0) || 717 (kg->kg_slptime < swap_idle_threshold2))) { 718 mtx_unlock_spin(&sched_lock); 719 PROC_UNLOCK(p); 720 goto nextproc; 721 } 722 if (minslptime > kg->kg_slptime) 723 minslptime = kg->kg_slptime; 724 } 725 726 mtx_unlock_spin(&sched_lock); 727 ++vm->vm_refcnt; 728 /* 729 * do not swapout a process that 730 * is waiting for VM 731 * data structures there is a 732 * possible deadlock. 733 */ 734 if (!vm_map_trylock(&vm->vm_map)) { 735 vmspace_free(vm); 736 PROC_UNLOCK(p); 737 goto nextproc; 738 } 739 vm_map_unlock(&vm->vm_map); 740 /* 741 * If the process has been asleep for awhile and had 742 * most of its pages taken away already, swap it out. 743 */ 744 if ((action & VM_SWAP_NORMAL) || 745 ((action & VM_SWAP_IDLE) && 746 (minslptime > swap_idle_threshold2))) { 747 sx_sunlock(&allproc_lock); 748 swapout(p); 749 vmspace_free(vm); 750 didswap++; 751 goto retry; 752 } 753 PROC_UNLOCK(p); 754 vmspace_free(vm); 755 } 756 nextproc: 757 continue; 758 } 759 sx_sunlock(&allproc_lock); 760 /* 761 * If we swapped something out, and another process needed memory, 762 * then wakeup the sched process. 763 */ 764 if (didswap) 765 wakeup(&proc0); 766 } 767 768 static void 769 swapout(p) 770 struct proc *p; 771 { 772 struct thread *td; 773 774 PROC_LOCK_ASSERT(p, MA_OWNED); 775 #if defined(SWAP_DEBUG) 776 printf("swapping out %d\n", p->p_pid); 777 #endif 778 ++p->p_stats->p_ru.ru_nswap; 779 /* 780 * remember the process resident count 781 */ 782 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 783 784 mtx_lock_spin(&sched_lock); 785 p->p_sflag &= ~PS_INMEM; 786 p->p_sflag |= PS_SWAPPING; 787 PROC_UNLOCK(p); 788 FOREACH_THREAD_IN_PROC (p, td) 789 if (td->td_state == TDS_RUNQ) /* XXXKSE */ 790 remrunqueue(td); /* XXXKSE */ 791 mtx_unlock_spin(&sched_lock); 792 793 vm_proc_swapout(p); 794 FOREACH_THREAD_IN_PROC(p, td) 795 pmap_swapout_thread(td); 796 mtx_lock_spin(&sched_lock); 797 p->p_sflag &= ~PS_SWAPPING; 798 p->p_swtime = 0; 799 mtx_unlock_spin(&sched_lock); 800 } 801 #endif /* !NO_SWAPPING */ 802