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 63 #include <sys/cdefs.h> 64 __FBSDID("$FreeBSD$"); 65 66 #include "opt_vm.h" 67 68 #include <sys/param.h> 69 #include <sys/systm.h> 70 #include <sys/limits.h> 71 #include <sys/lock.h> 72 #include <sys/mutex.h> 73 #include <sys/proc.h> 74 #include <sys/resourcevar.h> 75 #include <sys/shm.h> 76 #include <sys/vmmeter.h> 77 #include <sys/sx.h> 78 #include <sys/sysctl.h> 79 80 #include <sys/kernel.h> 81 #include <sys/ktr.h> 82 #include <sys/unistd.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 VM_OBJECT_LOCK(upobj); 269 if (upobj->resident_page_count != UAREA_PAGES) 270 panic("vm_proc_dispose: incorrect number of pages in upobj"); 271 vm_page_lock_queues(); 272 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 273 vm_page_busy(m); 274 vm_page_unwire(m, 0); 275 vm_page_free(m); 276 } 277 vm_page_unlock_queues(); 278 VM_OBJECT_UNLOCK(upobj); 279 up = (vm_offset_t)p->p_uarea; 280 pmap_qremove(up, UAREA_PAGES); 281 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 282 vm_object_deallocate(upobj); 283 } 284 285 #ifndef NO_SWAPPING 286 /* 287 * Allow the U area for a process to be prejudicially paged out. 288 */ 289 static void 290 vm_proc_swapout(struct proc *p) 291 { 292 vm_object_t upobj; 293 vm_offset_t up; 294 vm_page_t m; 295 296 upobj = p->p_upages_obj; 297 VM_OBJECT_LOCK(upobj); 298 if (upobj->resident_page_count != UAREA_PAGES) 299 panic("vm_proc_dispose: incorrect number of pages in upobj"); 300 vm_page_lock_queues(); 301 TAILQ_FOREACH(m, &upobj->memq, listq) { 302 vm_page_dirty(m); 303 vm_page_unwire(m, 0); 304 } 305 vm_page_unlock_queues(); 306 VM_OBJECT_UNLOCK(upobj); 307 up = (vm_offset_t)p->p_uarea; 308 pmap_qremove(up, UAREA_PAGES); 309 } 310 311 /* 312 * Bring the U area for a specified process back in. 313 */ 314 static void 315 vm_proc_swapin(struct proc *p) 316 { 317 vm_page_t ma[UAREA_PAGES]; 318 vm_object_t upobj; 319 vm_offset_t up; 320 vm_page_t m; 321 int rv; 322 int i; 323 324 upobj = p->p_upages_obj; 325 VM_OBJECT_LOCK(upobj); 326 for (i = 0; i < UAREA_PAGES; i++) { 327 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 328 if (m->valid != VM_PAGE_BITS_ALL) { 329 rv = vm_pager_get_pages(upobj, &m, 1, 0); 330 if (rv != VM_PAGER_OK) 331 panic("vm_proc_swapin: cannot get upage"); 332 } 333 ma[i] = m; 334 } 335 if (upobj->resident_page_count != UAREA_PAGES) 336 panic("vm_proc_swapin: lost pages from upobj"); 337 vm_page_lock_queues(); 338 TAILQ_FOREACH(m, &upobj->memq, listq) { 339 m->valid = VM_PAGE_BITS_ALL; 340 vm_page_wire(m); 341 vm_page_wakeup(m); 342 } 343 vm_page_unlock_queues(); 344 VM_OBJECT_UNLOCK(upobj); 345 up = (vm_offset_t)p->p_uarea; 346 pmap_qenter(up, ma, UAREA_PAGES); 347 } 348 349 /* 350 * Swap in the UAREAs of all processes swapped out to the given device. 351 * The pages in the UAREA are marked dirty and their swap metadata is freed. 352 */ 353 void 354 vm_proc_swapin_all(int devidx) 355 { 356 struct proc *p; 357 vm_object_t object; 358 vm_page_t m; 359 360 retry: 361 sx_slock(&allproc_lock); 362 FOREACH_PROC_IN_SYSTEM(p) { 363 PROC_LOCK(p); 364 object = p->p_upages_obj; 365 if (object != NULL) { 366 VM_OBJECT_LOCK(object); 367 if (swap_pager_isswapped(object, devidx)) { 368 VM_OBJECT_UNLOCK(object); 369 sx_sunlock(&allproc_lock); 370 faultin(p); 371 PROC_UNLOCK(p); 372 VM_OBJECT_LOCK(object); 373 vm_page_lock_queues(); 374 TAILQ_FOREACH(m, &object->memq, listq) 375 vm_page_dirty(m); 376 vm_page_unlock_queues(); 377 swap_pager_freespace(object, 0, 378 object->un_pager.swp.swp_bcount); 379 VM_OBJECT_UNLOCK(object); 380 goto retry; 381 } 382 VM_OBJECT_UNLOCK(object); 383 } 384 PROC_UNLOCK(p); 385 } 386 sx_sunlock(&allproc_lock); 387 } 388 #endif 389 390 #ifndef KSTACK_MAX_PAGES 391 #define KSTACK_MAX_PAGES 32 392 #endif 393 394 /* 395 * Create the kernel stack (including pcb for i386) for a new thread. 396 * This routine directly affects the fork perf for a process and 397 * create performance for a thread. 398 */ 399 void 400 vm_thread_new(struct thread *td, int pages) 401 { 402 vm_object_t ksobj; 403 vm_offset_t ks; 404 vm_page_t m, ma[KSTACK_MAX_PAGES]; 405 int i; 406 407 /* Bounds check */ 408 if (pages <= 1) 409 pages = KSTACK_PAGES; 410 else if (pages > KSTACK_MAX_PAGES) 411 pages = KSTACK_MAX_PAGES; 412 /* 413 * Allocate an object for the kstack. 414 */ 415 ksobj = vm_object_allocate(OBJT_DEFAULT, pages); 416 td->td_kstack_obj = ksobj; 417 /* 418 * Get a kernel virtual address for this thread's kstack. 419 */ 420 ks = kmem_alloc_nofault(kernel_map, 421 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 422 if (ks == 0) 423 panic("vm_thread_new: kstack allocation failed"); 424 if (KSTACK_GUARD_PAGES != 0) { 425 pmap_qremove(ks, KSTACK_GUARD_PAGES); 426 ks += KSTACK_GUARD_PAGES * PAGE_SIZE; 427 } 428 td->td_kstack = ks; 429 /* 430 * Knowing the number of pages allocated is useful when you 431 * want to deallocate them. 432 */ 433 td->td_kstack_pages = pages; 434 /* 435 * For the length of the stack, link in a real page of ram for each 436 * page of stack. 437 */ 438 VM_OBJECT_LOCK(ksobj); 439 for (i = 0; i < pages; i++) { 440 /* 441 * Get a kernel stack page. 442 */ 443 m = vm_page_grab(ksobj, i, 444 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 445 ma[i] = m; 446 vm_page_lock_queues(); 447 vm_page_wakeup(m); 448 m->valid = VM_PAGE_BITS_ALL; 449 vm_page_unlock_queues(); 450 } 451 VM_OBJECT_UNLOCK(ksobj); 452 pmap_qenter(ks, ma, pages); 453 } 454 455 /* 456 * Dispose of a thread's kernel stack. 457 */ 458 void 459 vm_thread_dispose(struct thread *td) 460 { 461 vm_object_t ksobj; 462 vm_offset_t ks; 463 vm_page_t m; 464 int i, pages; 465 466 pages = td->td_kstack_pages; 467 ksobj = td->td_kstack_obj; 468 ks = td->td_kstack; 469 pmap_qremove(ks, pages); 470 VM_OBJECT_LOCK(ksobj); 471 for (i = 0; i < pages; i++) { 472 m = vm_page_lookup(ksobj, i); 473 if (m == NULL) 474 panic("vm_thread_dispose: kstack already missing?"); 475 vm_page_lock_queues(); 476 vm_page_busy(m); 477 vm_page_unwire(m, 0); 478 vm_page_free(m); 479 vm_page_unlock_queues(); 480 } 481 VM_OBJECT_UNLOCK(ksobj); 482 vm_object_deallocate(ksobj); 483 kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 484 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 485 } 486 487 /* 488 * Allow a thread's kernel stack to be paged out. 489 */ 490 void 491 vm_thread_swapout(struct thread *td) 492 { 493 vm_object_t ksobj; 494 vm_page_t m; 495 int i, pages; 496 497 #ifdef __alpha__ 498 /* 499 * Make sure we aren't fpcurthread. 500 */ 501 alpha_fpstate_save(td, 1); 502 #endif 503 pages = td->td_kstack_pages; 504 ksobj = td->td_kstack_obj; 505 pmap_qremove(td->td_kstack, pages); 506 VM_OBJECT_LOCK(ksobj); 507 for (i = 0; i < pages; i++) { 508 m = vm_page_lookup(ksobj, i); 509 if (m == NULL) 510 panic("vm_thread_swapout: kstack already missing?"); 511 vm_page_lock_queues(); 512 vm_page_dirty(m); 513 vm_page_unwire(m, 0); 514 vm_page_unlock_queues(); 515 } 516 VM_OBJECT_UNLOCK(ksobj); 517 } 518 519 /* 520 * Bring the kernel stack for a specified thread back in. 521 */ 522 void 523 vm_thread_swapin(struct thread *td) 524 { 525 vm_object_t ksobj; 526 vm_page_t m, ma[KSTACK_MAX_PAGES]; 527 int i, pages, rv; 528 529 pages = td->td_kstack_pages; 530 ksobj = td->td_kstack_obj; 531 VM_OBJECT_LOCK(ksobj); 532 for (i = 0; i < pages; i++) { 533 m = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 534 if (m->valid != VM_PAGE_BITS_ALL) { 535 rv = vm_pager_get_pages(ksobj, &m, 1, 0); 536 if (rv != VM_PAGER_OK) 537 panic("vm_thread_swapin: cannot get kstack for proc: %d", td->td_proc->p_pid); 538 m = vm_page_lookup(ksobj, i); 539 m->valid = VM_PAGE_BITS_ALL; 540 } 541 ma[i] = m; 542 vm_page_lock_queues(); 543 vm_page_wire(m); 544 vm_page_wakeup(m); 545 vm_page_unlock_queues(); 546 } 547 VM_OBJECT_UNLOCK(ksobj); 548 pmap_qenter(td->td_kstack, ma, pages); 549 #ifdef __alpha__ 550 /* 551 * The pcb may be at a different physical address now so cache the 552 * new address. 553 */ 554 td->td_md.md_pcbpaddr = (void *)vtophys((vm_offset_t)td->td_pcb); 555 #endif 556 } 557 558 /* 559 * Set up a variable-sized alternate kstack. 560 */ 561 void 562 vm_thread_new_altkstack(struct thread *td, int pages) 563 { 564 565 td->td_altkstack = td->td_kstack; 566 td->td_altkstack_obj = td->td_kstack_obj; 567 td->td_altkstack_pages = td->td_kstack_pages; 568 569 vm_thread_new(td, pages); 570 } 571 572 /* 573 * Restore the original kstack. 574 */ 575 void 576 vm_thread_dispose_altkstack(struct thread *td) 577 { 578 579 vm_thread_dispose(td); 580 581 td->td_kstack = td->td_altkstack; 582 td->td_kstack_obj = td->td_altkstack_obj; 583 td->td_kstack_pages = td->td_altkstack_pages; 584 td->td_altkstack = 0; 585 td->td_altkstack_obj = NULL; 586 td->td_altkstack_pages = 0; 587 } 588 589 /* 590 * Implement fork's actions on an address space. 591 * Here we arrange for the address space to be copied or referenced, 592 * allocate a user struct (pcb and kernel stack), then call the 593 * machine-dependent layer to fill those in and make the new process 594 * ready to run. The new process is set up so that it returns directly 595 * to user mode to avoid stack copying and relocation problems. 596 */ 597 void 598 vm_forkproc(td, p2, td2, flags) 599 struct thread *td; 600 struct proc *p2; 601 struct thread *td2; 602 int flags; 603 { 604 struct proc *p1 = td->td_proc; 605 struct user *up; 606 607 GIANT_REQUIRED; 608 609 if ((flags & RFPROC) == 0) { 610 /* 611 * Divorce the memory, if it is shared, essentially 612 * this changes shared memory amongst threads, into 613 * COW locally. 614 */ 615 if ((flags & RFMEM) == 0) { 616 if (p1->p_vmspace->vm_refcnt > 1) { 617 vmspace_unshare(p1); 618 } 619 } 620 cpu_fork(td, p2, td2, flags); 621 return; 622 } 623 624 if (flags & RFMEM) { 625 p2->p_vmspace = p1->p_vmspace; 626 p1->p_vmspace->vm_refcnt++; 627 } 628 629 while (vm_page_count_severe()) { 630 VM_WAIT; 631 } 632 633 if ((flags & RFMEM) == 0) { 634 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 635 636 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 637 638 if (p1->p_vmspace->vm_shm) 639 shmfork(p1, p2); 640 } 641 642 /* XXXKSE this is unsatisfactory but should be adequate */ 643 up = p2->p_uarea; 644 MPASS(p2->p_sigacts != NULL); 645 646 /* 647 * p_stats currently points at fields in the user struct 648 * but not at &u, instead at p_addr. Copy parts of 649 * p_stats; zero the rest of p_stats (statistics). 650 */ 651 p2->p_stats = &up->u_stats; 652 bzero(&up->u_stats.pstat_startzero, 653 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 654 (caddr_t) &up->u_stats.pstat_startzero)); 655 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 656 ((caddr_t) &up->u_stats.pstat_endcopy - 657 (caddr_t) &up->u_stats.pstat_startcopy)); 658 659 /* 660 * cpu_fork will copy and update the pcb, set up the kernel stack, 661 * and make the child ready to run. 662 */ 663 cpu_fork(td, p2, td2, flags); 664 } 665 666 /* 667 * Called after process has been wait(2)'ed apon and is being reaped. 668 * The idea is to reclaim resources that we could not reclaim while 669 * the process was still executing. 670 */ 671 void 672 vm_waitproc(p) 673 struct proc *p; 674 { 675 676 GIANT_REQUIRED; 677 vmspace_exitfree(p); /* and clean-out the vmspace */ 678 } 679 680 /* 681 * Set default limits for VM system. 682 * Called for proc 0, and then inherited by all others. 683 * 684 * XXX should probably act directly on proc0. 685 */ 686 static void 687 vm_init_limits(udata) 688 void *udata; 689 { 690 struct proc *p = udata; 691 int rss_limit; 692 693 /* 694 * Set up the initial limits on process VM. Set the maximum resident 695 * set size to be half of (reasonably) available memory. Since this 696 * is a soft limit, it comes into effect only when the system is out 697 * of memory - half of main memory helps to favor smaller processes, 698 * and reduces thrashing of the object cache. 699 */ 700 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 701 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 702 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 703 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 704 /* limit the limit to no less than 2MB */ 705 rss_limit = max(cnt.v_free_count, 512); 706 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 707 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 708 } 709 710 void 711 faultin(p) 712 struct proc *p; 713 { 714 #ifdef NO_SWAPPING 715 716 PROC_LOCK_ASSERT(p, MA_OWNED); 717 if ((p->p_sflag & PS_INMEM) == 0) 718 panic("faultin: proc swapped out with NO_SWAPPING!"); 719 #else /* !NO_SWAPPING */ 720 struct thread *td; 721 722 GIANT_REQUIRED; 723 PROC_LOCK_ASSERT(p, MA_OWNED); 724 /* 725 * If another process is swapping in this process, 726 * just wait until it finishes. 727 */ 728 if (p->p_sflag & PS_SWAPPINGIN) 729 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 730 else if ((p->p_sflag & PS_INMEM) == 0) { 731 /* 732 * Don't let another thread swap process p out while we are 733 * busy swapping it in. 734 */ 735 ++p->p_lock; 736 mtx_lock_spin(&sched_lock); 737 p->p_sflag |= PS_SWAPPINGIN; 738 mtx_unlock_spin(&sched_lock); 739 PROC_UNLOCK(p); 740 741 vm_proc_swapin(p); 742 FOREACH_THREAD_IN_PROC(p, td) 743 vm_thread_swapin(td); 744 745 PROC_LOCK(p); 746 mtx_lock_spin(&sched_lock); 747 p->p_sflag &= ~PS_SWAPPINGIN; 748 p->p_sflag |= PS_INMEM; 749 FOREACH_THREAD_IN_PROC(p, td) { 750 TD_CLR_SWAPPED(td); 751 if (TD_CAN_RUN(td)) 752 setrunnable(td); 753 } 754 mtx_unlock_spin(&sched_lock); 755 756 wakeup(&p->p_sflag); 757 758 /* Allow other threads to swap p out now. */ 759 --p->p_lock; 760 } 761 #endif /* NO_SWAPPING */ 762 } 763 764 /* 765 * This swapin algorithm attempts to swap-in processes only if there 766 * is enough space for them. Of course, if a process waits for a long 767 * time, it will be swapped in anyway. 768 * 769 * XXXKSE - process with the thread with highest priority counts.. 770 * 771 * Giant is still held at this point, to be released in tsleep. 772 */ 773 /* ARGSUSED*/ 774 static void 775 scheduler(dummy) 776 void *dummy; 777 { 778 struct proc *p; 779 struct thread *td; 780 int pri; 781 struct proc *pp; 782 int ppri; 783 784 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 785 /* GIANT_REQUIRED */ 786 787 loop: 788 if (vm_page_count_min()) { 789 VM_WAIT; 790 goto loop; 791 } 792 793 pp = NULL; 794 ppri = INT_MIN; 795 sx_slock(&allproc_lock); 796 FOREACH_PROC_IN_SYSTEM(p) { 797 struct ksegrp *kg; 798 if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { 799 continue; 800 } 801 mtx_lock_spin(&sched_lock); 802 FOREACH_THREAD_IN_PROC(p, td) { 803 /* 804 * An otherwise runnable thread of a process 805 * swapped out has only the TDI_SWAPPED bit set. 806 * 807 */ 808 if (td->td_inhibitors == TDI_SWAPPED) { 809 kg = td->td_ksegrp; 810 pri = p->p_swtime + kg->kg_slptime; 811 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 812 pri -= kg->kg_nice * 8; 813 } 814 815 /* 816 * if this ksegrp is higher priority 817 * and there is enough space, then select 818 * this process instead of the previous 819 * selection. 820 */ 821 if (pri > ppri) { 822 pp = p; 823 ppri = pri; 824 } 825 } 826 } 827 mtx_unlock_spin(&sched_lock); 828 } 829 sx_sunlock(&allproc_lock); 830 831 /* 832 * Nothing to do, back to sleep. 833 */ 834 if ((p = pp) == NULL) { 835 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 836 goto loop; 837 } 838 PROC_LOCK(p); 839 840 /* 841 * Another process may be bringing or may have already 842 * brought this process in while we traverse all threads. 843 * Or, this process may even be being swapped out again. 844 */ 845 if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { 846 PROC_UNLOCK(p); 847 goto loop; 848 } 849 850 mtx_lock_spin(&sched_lock); 851 p->p_sflag &= ~PS_SWAPINREQ; 852 mtx_unlock_spin(&sched_lock); 853 854 /* 855 * We would like to bring someone in. (only if there is space). 856 * [What checks the space? ] 857 */ 858 faultin(p); 859 PROC_UNLOCK(p); 860 mtx_lock_spin(&sched_lock); 861 p->p_swtime = 0; 862 mtx_unlock_spin(&sched_lock); 863 goto loop; 864 } 865 866 #ifndef NO_SWAPPING 867 868 /* 869 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 870 */ 871 static int swap_idle_threshold1 = 2; 872 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW, 873 &swap_idle_threshold1, 0, "Guaranteed swapped in time for a process"); 874 875 /* 876 * Swap_idle_threshold2 is the time that a process can be idle before 877 * it will be swapped out, if idle swapping is enabled. 878 */ 879 static int swap_idle_threshold2 = 10; 880 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW, 881 &swap_idle_threshold2, 0, "Time before a process will be swapped out"); 882 883 /* 884 * Swapout is driven by the pageout daemon. Very simple, we find eligible 885 * procs and unwire their u-areas. We try to always "swap" at least one 886 * process in case we need the room for a swapin. 887 * If any procs have been sleeping/stopped for at least maxslp seconds, 888 * they are swapped. Else, we swap the longest-sleeping or stopped process, 889 * if any, otherwise the longest-resident process. 890 */ 891 void 892 swapout_procs(action) 893 int action; 894 { 895 struct proc *p; 896 struct thread *td; 897 struct ksegrp *kg; 898 int didswap = 0; 899 900 GIANT_REQUIRED; 901 902 retry: 903 sx_slock(&allproc_lock); 904 FOREACH_PROC_IN_SYSTEM(p) { 905 struct vmspace *vm; 906 int minslptime = 100000; 907 908 /* 909 * Watch out for a process in 910 * creation. It may have no 911 * address space or lock yet. 912 */ 913 mtx_lock_spin(&sched_lock); 914 if (p->p_state == PRS_NEW) { 915 mtx_unlock_spin(&sched_lock); 916 continue; 917 } 918 mtx_unlock_spin(&sched_lock); 919 920 /* 921 * An aio daemon switches its 922 * address space while running. 923 * Perform a quick check whether 924 * a process has P_SYSTEM. 925 */ 926 if ((p->p_flag & P_SYSTEM) != 0) 927 continue; 928 929 /* 930 * Do not swapout a process that 931 * is waiting for VM data 932 * structures as there is a possible 933 * deadlock. Test this first as 934 * this may block. 935 * 936 * Lock the map until swapout 937 * finishes, or a thread of this 938 * process may attempt to alter 939 * the map. 940 */ 941 PROC_LOCK(p); 942 vm = p->p_vmspace; 943 KASSERT(vm != NULL, 944 ("swapout_procs: a process has no address space")); 945 ++vm->vm_refcnt; 946 PROC_UNLOCK(p); 947 if (!vm_map_trylock(&vm->vm_map)) 948 goto nextproc1; 949 950 PROC_LOCK(p); 951 if (p->p_lock != 0 || 952 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) 953 ) != 0) { 954 goto nextproc2; 955 } 956 /* 957 * only aiod changes vmspace, however it will be 958 * skipped because of the if statement above checking 959 * for P_SYSTEM 960 */ 961 if ((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) != PS_INMEM) 962 goto nextproc2; 963 964 switch (p->p_state) { 965 default: 966 /* Don't swap out processes in any sort 967 * of 'special' state. */ 968 break; 969 970 case PRS_NORMAL: 971 mtx_lock_spin(&sched_lock); 972 /* 973 * do not swapout a realtime process 974 * Check all the thread groups.. 975 */ 976 FOREACH_KSEGRP_IN_PROC(p, kg) { 977 if (PRI_IS_REALTIME(kg->kg_pri_class)) 978 goto nextproc; 979 980 /* 981 * Guarantee swap_idle_threshold1 982 * time in memory. 983 */ 984 if (kg->kg_slptime < swap_idle_threshold1) 985 goto nextproc; 986 987 /* 988 * Do not swapout a process if it is 989 * waiting on a critical event of some 990 * kind or there is a thread whose 991 * pageable memory may be accessed. 992 * 993 * This could be refined to support 994 * swapping out a thread. 995 */ 996 FOREACH_THREAD_IN_GROUP(kg, td) { 997 if ((td->td_priority) < PSOCK || 998 !thread_safetoswapout(td)) 999 goto nextproc; 1000 } 1001 /* 1002 * If the system is under memory stress, 1003 * or if we are swapping 1004 * idle processes >= swap_idle_threshold2, 1005 * then swap the process out. 1006 */ 1007 if (((action & VM_SWAP_NORMAL) == 0) && 1008 (((action & VM_SWAP_IDLE) == 0) || 1009 (kg->kg_slptime < swap_idle_threshold2))) 1010 goto nextproc; 1011 1012 if (minslptime > kg->kg_slptime) 1013 minslptime = kg->kg_slptime; 1014 } 1015 1016 /* 1017 * If the process has been asleep for awhile and had 1018 * most of its pages taken away already, swap it out. 1019 */ 1020 if ((action & VM_SWAP_NORMAL) || 1021 ((action & VM_SWAP_IDLE) && 1022 (minslptime > swap_idle_threshold2))) { 1023 swapout(p); 1024 didswap++; 1025 mtx_unlock_spin(&sched_lock); 1026 PROC_UNLOCK(p); 1027 vm_map_unlock(&vm->vm_map); 1028 vmspace_free(vm); 1029 sx_sunlock(&allproc_lock); 1030 goto retry; 1031 } 1032 nextproc: 1033 mtx_unlock_spin(&sched_lock); 1034 } 1035 nextproc2: 1036 PROC_UNLOCK(p); 1037 vm_map_unlock(&vm->vm_map); 1038 nextproc1: 1039 vmspace_free(vm); 1040 continue; 1041 } 1042 sx_sunlock(&allproc_lock); 1043 /* 1044 * If we swapped something out, and another process needed memory, 1045 * then wakeup the sched process. 1046 */ 1047 if (didswap) 1048 wakeup(&proc0); 1049 } 1050 1051 static void 1052 swapout(p) 1053 struct proc *p; 1054 { 1055 struct thread *td; 1056 1057 PROC_LOCK_ASSERT(p, MA_OWNED); 1058 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 1059 #if defined(SWAP_DEBUG) 1060 printf("swapping out %d\n", p->p_pid); 1061 #endif 1062 1063 /* 1064 * The states of this process and its threads may have changed 1065 * by now. Assuming that there is only one pageout daemon thread, 1066 * this process should still be in memory. 1067 */ 1068 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) == PS_INMEM, 1069 ("swapout: lost a swapout race?")); 1070 1071 #if defined(INVARIANTS) 1072 /* 1073 * Make sure that all threads are safe to be swapped out. 1074 * 1075 * Alternatively, we could swap out only safe threads. 1076 */ 1077 FOREACH_THREAD_IN_PROC(p, td) { 1078 KASSERT(thread_safetoswapout(td), 1079 ("swapout: there is a thread not safe for swapout")); 1080 } 1081 #endif /* INVARIANTS */ 1082 1083 ++p->p_stats->p_ru.ru_nswap; 1084 /* 1085 * remember the process resident count 1086 */ 1087 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 1088 1089 p->p_sflag &= ~PS_INMEM; 1090 p->p_sflag |= PS_SWAPPINGOUT; 1091 PROC_UNLOCK(p); 1092 FOREACH_THREAD_IN_PROC(p, td) 1093 TD_SET_SWAPPED(td); 1094 mtx_unlock_spin(&sched_lock); 1095 1096 vm_proc_swapout(p); 1097 FOREACH_THREAD_IN_PROC(p, td) 1098 vm_thread_swapout(td); 1099 1100 PROC_LOCK(p); 1101 mtx_lock_spin(&sched_lock); 1102 p->p_sflag &= ~PS_SWAPPINGOUT; 1103 p->p_swtime = 0; 1104 } 1105 #endif /* !NO_SWAPPING */ 1106