vm_glue.c revision 100884
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: head/sys/vm/vm_glue.c 100884 2002-07-29 18:33:32Z julian $ 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 97extern int maxslp; 98 99/* 100 * System initialization 101 * 102 * Note: proc0 from proc.h 103 */ 104static void vm_init_limits(void *); 105SYSINIT(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 */ 112static void scheduler(void *); 113SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 114 115#ifndef NO_SWAPPING 116static void swapout(struct proc *); 117static void vm_proc_swapin(struct proc *p); 118static void vm_proc_swapout(struct proc *p); 119#endif 120 121/* 122 * MPSAFE 123 */ 124int 125kernacc(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 */ 145int 146useracc(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 */ 178void 179vslock(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 */ 191void 192vsunlock(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 */ 206void 207vm_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 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE); 240 m->valid = VM_PAGE_BITS_ALL; 241 } 242 243 /* 244 * Enter the pages into the kernel address space. 245 */ 246 pmap_qenter(up, ma, UAREA_PAGES); 247} 248 249/* 250 * Dispose the U area for a process that has exited. 251 * This routine directly impacts the exit perf of a process. 252 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 253 */ 254void 255vm_proc_dispose(struct proc *p) 256{ 257 vm_object_t upobj; 258 vm_offset_t up; 259 vm_page_t m; 260 261 upobj = p->p_upages_obj; 262 if (upobj->resident_page_count != UAREA_PAGES) 263 panic("vm_proc_dispose: incorrect number of pages in upobj"); 264 vm_page_lock_queues(); 265 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 266 vm_page_busy(m); 267 vm_page_unwire(m, 0); 268 vm_page_free(m); 269 } 270 vm_page_unlock_queues(); 271 up = (vm_offset_t)p->p_uarea; 272 pmap_qremove(up, UAREA_PAGES); 273 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 274 vm_object_deallocate(upobj); 275} 276 277#ifndef NO_SWAPPING 278/* 279 * Allow the U area for a process to be prejudicially paged out. 280 */ 281void 282vm_proc_swapout(struct proc *p) 283{ 284 vm_object_t upobj; 285 vm_offset_t up; 286 vm_page_t m; 287 288 upobj = p->p_upages_obj; 289 if (upobj->resident_page_count != UAREA_PAGES) 290 panic("vm_proc_dispose: incorrect number of pages in upobj"); 291 vm_page_lock_queues(); 292 TAILQ_FOREACH(m, &upobj->memq, listq) { 293 vm_page_dirty(m); 294 vm_page_unwire(m, 0); 295 } 296 vm_page_unlock_queues(); 297 up = (vm_offset_t)p->p_uarea; 298 pmap_qremove(up, UAREA_PAGES); 299} 300 301/* 302 * Bring the U area for a specified process back in. 303 */ 304void 305vm_proc_swapin(struct proc *p) 306{ 307 vm_page_t ma[UAREA_PAGES]; 308 vm_object_t upobj; 309 vm_offset_t up; 310 vm_page_t m; 311 int rv; 312 int i; 313 314 upobj = p->p_upages_obj; 315 for (i = 0; i < UAREA_PAGES; i++) { 316 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 317 if (m->valid != VM_PAGE_BITS_ALL) { 318 rv = vm_pager_get_pages(upobj, &m, 1, 0); 319 if (rv != VM_PAGER_OK) 320 panic("vm_proc_swapin: cannot get upage"); 321 } 322 ma[i] = m; 323 } 324 if (upobj->resident_page_count != UAREA_PAGES) 325 panic("vm_proc_swapin: lost pages from upobj"); 326 vm_page_lock_queues(); 327 TAILQ_FOREACH(m, &upobj->memq, listq) { 328 m->valid = VM_PAGE_BITS_ALL; 329 vm_page_wire(m); 330 vm_page_wakeup(m); 331 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE); 332 } 333 vm_page_unlock_queues(); 334 up = (vm_offset_t)p->p_uarea; 335 pmap_qenter(up, ma, UAREA_PAGES); 336} 337#endif 338 339/* 340 * Implement fork's actions on an address space. 341 * Here we arrange for the address space to be copied or referenced, 342 * allocate a user struct (pcb and kernel stack), then call the 343 * machine-dependent layer to fill those in and make the new process 344 * ready to run. The new process is set up so that it returns directly 345 * to user mode to avoid stack copying and relocation problems. 346 */ 347void 348vm_forkproc(td, p2, td2, flags) 349 struct thread *td; 350 struct proc *p2; 351 struct thread *td2; 352 int flags; 353{ 354 struct proc *p1 = td->td_proc; 355 struct user *up; 356 357 GIANT_REQUIRED; 358 359 if ((flags & RFPROC) == 0) { 360 /* 361 * Divorce the memory, if it is shared, essentially 362 * this changes shared memory amongst threads, into 363 * COW locally. 364 */ 365 if ((flags & RFMEM) == 0) { 366 if (p1->p_vmspace->vm_refcnt > 1) { 367 vmspace_unshare(p1); 368 } 369 } 370 cpu_fork(td, p2, td2, flags); 371 return; 372 } 373 374 if (flags & RFMEM) { 375 p2->p_vmspace = p1->p_vmspace; 376 p1->p_vmspace->vm_refcnt++; 377 } 378 379 while (vm_page_count_severe()) { 380 VM_WAIT; 381 } 382 383 if ((flags & RFMEM) == 0) { 384 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 385 386 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 387 388 if (p1->p_vmspace->vm_shm) 389 shmfork(p1, p2); 390 } 391 392 /* XXXKSE this is unsatisfactory but should be adequate */ 393 up = p2->p_uarea; 394 395 /* 396 * p_stats currently points at fields in the user struct 397 * but not at &u, instead at p_addr. Copy parts of 398 * p_stats; zero the rest of p_stats (statistics). 399 * 400 * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need 401 * to share sigacts, so we use the up->u_sigacts. 402 */ 403 p2->p_stats = &up->u_stats; 404 if (p2->p_sigacts == NULL) { 405 if (p2->p_procsig->ps_refcnt != 1) 406 printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); 407 p2->p_sigacts = &up->u_sigacts; 408 up->u_sigacts = *p1->p_sigacts; 409 } 410 411 bzero(&up->u_stats.pstat_startzero, 412 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 413 (caddr_t) &up->u_stats.pstat_startzero)); 414 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 415 ((caddr_t) &up->u_stats.pstat_endcopy - 416 (caddr_t) &up->u_stats.pstat_startcopy)); 417 418 419 /* 420 * cpu_fork will copy and update the pcb, set up the kernel stack, 421 * and make the child ready to run. 422 */ 423 cpu_fork(td, p2, td2, flags); 424} 425 426/* 427 * Called after process has been wait(2)'ed apon and is being reaped. 428 * The idea is to reclaim resources that we could not reclaim while 429 * the process was still executing. 430 */ 431void 432vm_waitproc(p) 433 struct proc *p; 434{ 435 struct thread *td; 436 437 GIANT_REQUIRED; 438 cpu_wait(p); 439/* XXXKSE by here there should not be any threads left! */ 440 FOREACH_THREAD_IN_PROC(p, td) { 441 panic("vm_waitproc: Survivor thread!"); 442 } 443 vmspace_exitfree(p); /* and clean-out the vmspace */ 444} 445 446/* 447 * Set default limits for VM system. 448 * Called for proc 0, and then inherited by all others. 449 * 450 * XXX should probably act directly on proc0. 451 */ 452static void 453vm_init_limits(udata) 454 void *udata; 455{ 456 struct proc *p = udata; 457 int rss_limit; 458 459 /* 460 * Set up the initial limits on process VM. Set the maximum resident 461 * set size to be half of (reasonably) available memory. Since this 462 * is a soft limit, it comes into effect only when the system is out 463 * of memory - half of main memory helps to favor smaller processes, 464 * and reduces thrashing of the object cache. 465 */ 466 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 467 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 468 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 469 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 470 /* limit the limit to no less than 2MB */ 471 rss_limit = max(cnt.v_free_count, 512); 472 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 473 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 474} 475 476void 477faultin(p) 478 struct proc *p; 479{ 480 481 GIANT_REQUIRED; 482 PROC_LOCK_ASSERT(p, MA_OWNED); 483 mtx_assert(&sched_lock, MA_OWNED); 484#ifdef NO_SWAPPING 485 if ((p->p_sflag & PS_INMEM) == 0) 486 panic("faultin: proc swapped out with NO_SWAPPING!"); 487#else 488 if ((p->p_sflag & PS_INMEM) == 0) { 489 struct thread *td; 490 491 ++p->p_lock; 492 /* 493 * If another process is swapping in this process, 494 * just wait until it finishes. 495 */ 496 if (p->p_sflag & PS_SWAPPINGIN) { 497 mtx_unlock_spin(&sched_lock); 498 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 499 mtx_lock_spin(&sched_lock); 500 --p->p_lock; 501 return; 502 } 503 504 p->p_sflag |= PS_SWAPPINGIN; 505 mtx_unlock_spin(&sched_lock); 506 PROC_UNLOCK(p); 507 508 vm_proc_swapin(p); 509 FOREACH_THREAD_IN_PROC (p, td) 510 pmap_swapin_thread(td); 511 512 PROC_LOCK(p); 513 mtx_lock_spin(&sched_lock); 514 FOREACH_THREAD_IN_PROC (p, td) 515 if (td->td_state == TDS_SWAPPED) /* XXXKSE */ 516 setrunqueue(td); 517 518 p->p_sflag &= ~PS_SWAPPINGIN; 519 p->p_sflag |= PS_INMEM; 520 wakeup(&p->p_sflag); 521 522 /* undo the effect of setting SLOCK above */ 523 --p->p_lock; 524 } 525#endif 526} 527 528/* 529 * This swapin algorithm attempts to swap-in processes only if there 530 * is enough space for them. Of course, if a process waits for a long 531 * time, it will be swapped in anyway. 532 * 533 * XXXKSE - process with the thread with highest priority counts.. 534 * 535 * Giant is still held at this point, to be released in tsleep. 536 */ 537/* ARGSUSED*/ 538static void 539scheduler(dummy) 540 void *dummy; 541{ 542 struct proc *p; 543 struct thread *td; 544 int pri; 545 struct proc *pp; 546 int ppri; 547 548 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 549 /* GIANT_REQUIRED */ 550 551loop: 552 if (vm_page_count_min()) { 553 VM_WAIT; 554 goto loop; 555 } 556 557 pp = NULL; 558 ppri = INT_MIN; 559 sx_slock(&allproc_lock); 560 FOREACH_PROC_IN_SYSTEM(p) { 561 struct ksegrp *kg; 562 if (p->p_sflag & (PS_INMEM | PS_SWAPPING | PS_SWAPPINGIN)) { 563 continue; 564 } 565 mtx_lock_spin(&sched_lock); 566 FOREACH_THREAD_IN_PROC(p, td) { 567 /* 568 * A runnable thread of a process swapped out is in 569 * TDS_SWAPPED. 570 */ 571 if (td->td_state == TDS_SWAPPED) { 572 kg = td->td_ksegrp; 573 pri = p->p_swtime + kg->kg_slptime; 574 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 575 pri -= kg->kg_nice * 8; 576 } 577 578 /* 579 * if this ksegrp is higher priority 580 * and there is enough space, then select 581 * this process instead of the previous 582 * selection. 583 */ 584 if (pri > ppri) { 585 pp = p; 586 ppri = pri; 587 } 588 } 589 } 590 mtx_unlock_spin(&sched_lock); 591 } 592 sx_sunlock(&allproc_lock); 593 594 /* 595 * Nothing to do, back to sleep. 596 */ 597 if ((p = pp) == NULL) { 598 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 599 goto loop; 600 } 601 PROC_LOCK(p); 602 mtx_lock_spin(&sched_lock); 603 604 /* 605 * Another process may be bringing or may have already 606 * brought this process in while we traverse all threads. 607 * Or, this process may even be being swapped out again. 608 */ 609 if (p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) { 610 mtx_unlock_spin(&sched_lock); 611 PROC_UNLOCK(p); 612 goto loop; 613 } 614 615 p->p_sflag &= ~PS_SWAPINREQ; 616 617 /* 618 * We would like to bring someone in. (only if there is space). 619 * [What checks the space? ] 620 */ 621 faultin(p); 622 PROC_UNLOCK(p); 623 p->p_swtime = 0; 624 mtx_unlock_spin(&sched_lock); 625 goto loop; 626} 627 628#ifndef NO_SWAPPING 629 630/* 631 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 632 */ 633static int swap_idle_threshold1 = 2; 634SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, 635 CTLFLAG_RW, &swap_idle_threshold1, 0, ""); 636 637/* 638 * Swap_idle_threshold2 is the time that a process can be idle before 639 * it will be swapped out, if idle swapping is enabled. 640 */ 641static int swap_idle_threshold2 = 10; 642SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, 643 CTLFLAG_RW, &swap_idle_threshold2, 0, ""); 644 645/* 646 * Swapout is driven by the pageout daemon. Very simple, we find eligible 647 * procs and unwire their u-areas. We try to always "swap" at least one 648 * process in case we need the room for a swapin. 649 * If any procs have been sleeping/stopped for at least maxslp seconds, 650 * they are swapped. Else, we swap the longest-sleeping or stopped process, 651 * if any, otherwise the longest-resident process. 652 */ 653void 654swapout_procs(action) 655int action; 656{ 657 struct proc *p; 658 struct thread *td; 659 struct ksegrp *kg; 660 struct proc *outp, *outp2; 661 int outpri, outpri2; 662 int didswap = 0; 663 664 GIANT_REQUIRED; 665 666 outp = outp2 = NULL; 667 outpri = outpri2 = INT_MIN; 668retry: 669 sx_slock(&allproc_lock); 670 FOREACH_PROC_IN_SYSTEM(p) { 671 struct vmspace *vm; 672 int minslptime = 100000; 673 674 PROC_LOCK(p); 675 if (p->p_lock != 0 || 676 (p->p_flag & (P_STOPPED_SNGL|P_TRACED|P_SYSTEM|P_WEXIT)) != 0) { 677 PROC_UNLOCK(p); 678 continue; 679 } 680 /* 681 * only aiod changes vmspace, however it will be 682 * skipped because of the if statement above checking 683 * for P_SYSTEM 684 */ 685 vm = p->p_vmspace; 686 mtx_lock_spin(&sched_lock); 687 if ((p->p_sflag & (PS_INMEM|PS_SWAPPING|PS_SWAPPINGIN)) != PS_INMEM) { 688 mtx_unlock_spin(&sched_lock); 689 PROC_UNLOCK(p); 690 continue; 691 } 692 693 switch (p->p_state) { 694 default: 695 /* Don't swap out processes in any sort 696 * of 'special' state. */ 697 mtx_unlock_spin(&sched_lock); 698 PROC_UNLOCK(p); 699 continue; 700 701 case PRS_NORMAL: 702 /* 703 * do not swapout a realtime process 704 * Check all the thread groups.. 705 */ 706 FOREACH_KSEGRP_IN_PROC(p, kg) { 707 if (PRI_IS_REALTIME(kg->kg_pri_class)) { 708 mtx_unlock_spin(&sched_lock); 709 PROC_UNLOCK(p); 710 goto nextproc; 711 } 712 713 /* 714 * Do not swapout a process waiting 715 * on a critical event of some kind. 716 * Also guarantee swap_idle_threshold1 717 * time in memory. 718 */ 719 if (kg->kg_slptime < swap_idle_threshold1) { 720 mtx_unlock_spin(&sched_lock); 721 PROC_UNLOCK(p); 722 goto nextproc; 723 } 724 /* 725 * Do not swapout a process if there is 726 * a thread whose pageable memory may 727 * be accessed. 728 * 729 * This could be refined to support 730 * swapping out a thread. 731 */ 732 FOREACH_THREAD_IN_PROC(p, td) { 733 if ((td->td_priority) < PSOCK || 734 !(td->td_state == TDS_SLP || 735 td->td_state == TDS_RUNQ)) { 736 mtx_unlock_spin(&sched_lock); 737 PROC_UNLOCK(p); 738 goto nextproc; 739 } 740 } 741 /* 742 * If the system is under memory stress, 743 * or if we are swapping 744 * idle processes >= swap_idle_threshold2, 745 * then swap the process out. 746 */ 747 if (((action & VM_SWAP_NORMAL) == 0) && 748 (((action & VM_SWAP_IDLE) == 0) || 749 (kg->kg_slptime < swap_idle_threshold2))) { 750 mtx_unlock_spin(&sched_lock); 751 PROC_UNLOCK(p); 752 goto nextproc; 753 } 754 if (minslptime > kg->kg_slptime) 755 minslptime = kg->kg_slptime; 756 } 757 758 mtx_unlock_spin(&sched_lock); 759 ++vm->vm_refcnt; 760 /* 761 * do not swapout a process that 762 * is waiting for VM 763 * data structures there is a 764 * possible deadlock. 765 */ 766 if (!vm_map_trylock(&vm->vm_map)) { 767 vmspace_free(vm); 768 PROC_UNLOCK(p); 769 goto nextproc; 770 } 771 vm_map_unlock(&vm->vm_map); 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 sx_sunlock(&allproc_lock); 780 swapout(p); 781 vmspace_free(vm); 782 didswap++; 783 goto retry; 784 } 785 PROC_UNLOCK(p); 786 vmspace_free(vm); 787 } 788nextproc: 789 continue; 790 } 791 sx_sunlock(&allproc_lock); 792 /* 793 * If we swapped something out, and another process needed memory, 794 * then wakeup the sched process. 795 */ 796 if (didswap) 797 wakeup(&proc0); 798} 799 800static void 801swapout(p) 802 struct proc *p; 803{ 804 struct thread *td; 805 806 PROC_LOCK_ASSERT(p, MA_OWNED); 807#if defined(SWAP_DEBUG) 808 printf("swapping out %d\n", p->p_pid); 809#endif 810 mtx_lock_spin(&sched_lock); 811 812 /* 813 * Make sure that all threads are safe to be swapped out. 814 * 815 * Alternatively, we could swap out only safe threads. 816 */ 817 FOREACH_THREAD_IN_PROC(p, td) { 818 if (!(td->td_state == TDS_SLP || 819 td->td_state == TDS_RUNQ)) { 820 mtx_unlock_spin(&sched_lock); 821 return; 822 } 823 } 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 p->p_sflag &= ~PS_INMEM; 832 p->p_sflag |= PS_SWAPPING; 833 PROC_UNLOCK(p); 834 FOREACH_THREAD_IN_PROC (p, td) 835 if (td->td_state == TDS_RUNQ) { /* XXXKSE */ 836 remrunqueue(td); /* XXXKSE */ 837 td->td_state = TDS_SWAPPED; 838 } 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 mtx_unlock_spin(&sched_lock); 848} 849#endif /* !NO_SWAPPING */ 850