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 #include "opt_kstack_pages.h" 68 #include "opt_kstack_max_pages.h" 69 70 #include <sys/param.h> 71 #include <sys/systm.h> 72 #include <sys/limits.h> 73 #include <sys/lock.h> 74 #include <sys/mutex.h> 75 #include <sys/proc.h> 76 #include <sys/resourcevar.h> 77 #include <sys/shm.h> 78 #include <sys/vmmeter.h> 79 #include <sys/sx.h> 80 #include <sys/sysctl.h> 81 82 #include <sys/kernel.h> 83 #include <sys/ktr.h> 84 #include <sys/unistd.h> 85 86 #include <vm/vm.h> 87 #include <vm/vm_param.h> 88 #include <vm/pmap.h> 89 #include <vm/vm_map.h> 90 #include <vm/vm_page.h> 91 #include <vm/vm_pageout.h> 92 #include <vm/vm_object.h> 93 #include <vm/vm_kern.h> 94 #include <vm/vm_extern.h> 95 #include <vm/vm_pager.h> 96 #include <vm/swap_pager.h> 97 98 #include <sys/user.h> 99 100 extern int maxslp; 101 102 /* 103 * System initialization 104 * 105 * Note: proc0 from proc.h 106 */ 107 static void vm_init_limits(void *); 108 SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) 109 110 /* 111 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 112 * 113 * Note: run scheduling should be divorced from the vm system. 114 */ 115 static void scheduler(void *); 116 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_FIRST, scheduler, NULL) 117 118 #ifndef NO_SWAPPING 119 static void swapout(struct proc *); 120 static void vm_proc_swapin(struct proc *p); 121 static void vm_proc_swapout(struct proc *p); 122 #endif 123 124 /* 125 * MPSAFE 126 * 127 * WARNING! This code calls vm_map_check_protection() which only checks 128 * the associated vm_map_entry range. It does not determine whether the 129 * contents of the memory is actually readable or writable. In most cases 130 * just checking the vm_map_entry is sufficient within the kernel's address 131 * space. 132 */ 133 int 134 kernacc(addr, len, rw) 135 void *addr; 136 int len, rw; 137 { 138 boolean_t rv; 139 vm_offset_t saddr, eaddr; 140 vm_prot_t prot; 141 142 KASSERT((rw & ~VM_PROT_ALL) == 0, 143 ("illegal ``rw'' argument to kernacc (%x)\n", rw)); 144 prot = rw; 145 saddr = trunc_page((vm_offset_t)addr); 146 eaddr = round_page((vm_offset_t)addr + len); 147 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 148 return (rv == TRUE); 149 } 150 151 /* 152 * MPSAFE 153 * 154 * WARNING! This code calls vm_map_check_protection() which only checks 155 * the associated vm_map_entry range. It does not determine whether the 156 * contents of the memory is actually readable or writable. vmapbuf(), 157 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be 158 * used in conjuction with this call. 159 */ 160 int 161 useracc(addr, len, rw) 162 void *addr; 163 int len, rw; 164 { 165 boolean_t rv; 166 vm_prot_t prot; 167 vm_map_t map; 168 169 KASSERT((rw & ~VM_PROT_ALL) == 0, 170 ("illegal ``rw'' argument to useracc (%x)\n", rw)); 171 prot = rw; 172 map = &curproc->p_vmspace->vm_map; 173 if ((vm_offset_t)addr + len > vm_map_max(map) || 174 (vm_offset_t)addr + len < (vm_offset_t)addr) { 175 return (FALSE); 176 } 177 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 178 round_page((vm_offset_t)addr + len), prot); 179 return (rv == TRUE); 180 } 181 182 /* 183 * MPSAFE 184 */ 185 void 186 vslock(addr, len) 187 void *addr; 188 u_int len; 189 { 190 191 vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), 192 round_page((vm_offset_t)addr + len), 193 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 194 } 195 196 /* 197 * MPSAFE 198 */ 199 void 200 vsunlock(addr, len) 201 void *addr; 202 u_int len; 203 { 204 205 vm_map_unwire(&curproc->p_vmspace->vm_map, 206 trunc_page((vm_offset_t)addr), 207 round_page((vm_offset_t)addr + len), 208 VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); 209 } 210 211 /* 212 * Create the U area for a new process. 213 * This routine directly affects the fork perf for a process. 214 */ 215 void 216 vm_proc_new(struct proc *p) 217 { 218 vm_page_t ma[UAREA_PAGES]; 219 vm_object_t upobj; 220 vm_offset_t up; 221 vm_page_t m; 222 u_int i; 223 224 /* 225 * Get a kernel virtual address for the U area for this process. 226 */ 227 up = kmem_alloc_nofault(kernel_map, UAREA_PAGES * PAGE_SIZE); 228 if (up == 0) 229 panic("vm_proc_new: upage allocation failed"); 230 p->p_uarea = (struct user *)up; 231 232 /* 233 * Allocate object and page(s) for the U area. 234 */ 235 upobj = vm_object_allocate(OBJT_DEFAULT, UAREA_PAGES); 236 p->p_upages_obj = upobj; 237 VM_OBJECT_LOCK(upobj); 238 for (i = 0; i < UAREA_PAGES; i++) { 239 m = vm_page_grab(upobj, i, 240 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 241 ma[i] = m; 242 243 vm_page_lock_queues(); 244 vm_page_wakeup(m); 245 m->valid = VM_PAGE_BITS_ALL; 246 vm_page_unlock_queues(); 247 } 248 VM_OBJECT_UNLOCK(upobj); 249 250 /* 251 * Enter the pages into the kernel address space. 252 */ 253 pmap_qenter(up, ma, UAREA_PAGES); 254 } 255 256 /* 257 * Dispose the U area for a process that has exited. 258 * This routine directly impacts the exit perf of a process. 259 * XXX proc_zone is marked UMA_ZONE_NOFREE, so this should never be called. 260 */ 261 void 262 vm_proc_dispose(struct proc *p) 263 { 264 vm_object_t upobj; 265 vm_offset_t up; 266 vm_page_t m; 267 268 upobj = p->p_upages_obj; 269 VM_OBJECT_LOCK(upobj); 270 if (upobj->resident_page_count != UAREA_PAGES) 271 panic("vm_proc_dispose: incorrect number of pages in upobj"); 272 vm_page_lock_queues(); 273 while ((m = TAILQ_FIRST(&upobj->memq)) != NULL) { 274 vm_page_busy(m); 275 vm_page_unwire(m, 0); 276 vm_page_free(m); 277 } 278 vm_page_unlock_queues(); 279 VM_OBJECT_UNLOCK(upobj); 280 up = (vm_offset_t)p->p_uarea; 281 pmap_qremove(up, UAREA_PAGES); 282 kmem_free(kernel_map, up, UAREA_PAGES * PAGE_SIZE); 283 vm_object_deallocate(upobj); 284 } 285 286 #ifndef NO_SWAPPING 287 /* 288 * Allow the U area for a process to be prejudicially paged out. 289 */ 290 static void 291 vm_proc_swapout(struct proc *p) 292 { 293 vm_object_t upobj; 294 vm_offset_t up; 295 vm_page_t m; 296 297 upobj = p->p_upages_obj; 298 VM_OBJECT_LOCK(upobj); 299 if (upobj->resident_page_count != UAREA_PAGES) 300 panic("vm_proc_dispose: incorrect number of pages in upobj"); 301 vm_page_lock_queues(); 302 TAILQ_FOREACH(m, &upobj->memq, listq) { 303 vm_page_dirty(m); 304 vm_page_unwire(m, 0); 305 } 306 vm_page_unlock_queues(); 307 VM_OBJECT_UNLOCK(upobj); 308 up = (vm_offset_t)p->p_uarea; 309 pmap_qremove(up, UAREA_PAGES); 310 } 311 312 /* 313 * Bring the U area for a specified process back in. 314 */ 315 static void 316 vm_proc_swapin(struct proc *p) 317 { 318 vm_page_t ma[UAREA_PAGES]; 319 vm_object_t upobj; 320 vm_offset_t up; 321 vm_page_t m; 322 int rv; 323 int i; 324 325 upobj = p->p_upages_obj; 326 VM_OBJECT_LOCK(upobj); 327 for (i = 0; i < UAREA_PAGES; i++) { 328 m = vm_page_grab(upobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 329 if (m->valid != VM_PAGE_BITS_ALL) { 330 rv = vm_pager_get_pages(upobj, &m, 1, 0); 331 if (rv != VM_PAGER_OK) 332 panic("vm_proc_swapin: cannot get upage"); 333 } 334 ma[i] = m; 335 } 336 if (upobj->resident_page_count != UAREA_PAGES) 337 panic("vm_proc_swapin: lost pages from upobj"); 338 vm_page_lock_queues(); 339 TAILQ_FOREACH(m, &upobj->memq, listq) { 340 m->valid = VM_PAGE_BITS_ALL; 341 vm_page_wire(m); 342 vm_page_wakeup(m); 343 } 344 vm_page_unlock_queues(); 345 VM_OBJECT_UNLOCK(upobj); 346 up = (vm_offset_t)p->p_uarea; 347 pmap_qenter(up, ma, UAREA_PAGES); 348 } 349 350 /* 351 * Swap in the UAREAs of all processes swapped out to the given device. 352 * The pages in the UAREA are marked dirty and their swap metadata is freed. 353 */ 354 void 355 vm_proc_swapin_all(struct swdevt *devidx) 356 { 357 struct proc *p; 358 vm_object_t object; 359 vm_page_t m; 360 361 retry: 362 sx_slock(&allproc_lock); 363 FOREACH_PROC_IN_SYSTEM(p) { 364 PROC_LOCK(p); 365 object = p->p_upages_obj; 366 if (object != NULL) { 367 VM_OBJECT_LOCK(object); 368 if (swap_pager_isswapped(object, devidx)) { 369 VM_OBJECT_UNLOCK(object); 370 sx_sunlock(&allproc_lock); 371 faultin(p); 372 PROC_UNLOCK(p); 373 VM_OBJECT_LOCK(object); 374 vm_page_lock_queues(); 375 TAILQ_FOREACH(m, &object->memq, listq) 376 vm_page_dirty(m); 377 vm_page_unlock_queues(); 378 swap_pager_freespace(object, 0, 379 object->un_pager.swp.swp_bcount); 380 VM_OBJECT_UNLOCK(object); 381 goto retry; 382 } 383 VM_OBJECT_UNLOCK(object); 384 } 385 PROC_UNLOCK(p); 386 } 387 sx_sunlock(&allproc_lock); 388 } 389 #endif 390 391 #ifndef KSTACK_MAX_PAGES 392 #define KSTACK_MAX_PAGES 32 393 #endif 394 395 /* 396 * Create the kernel stack (including pcb for i386) for a new thread. 397 * This routine directly affects the fork perf for a process and 398 * create performance for a thread. 399 */ 400 void 401 vm_thread_new(struct thread *td, int pages) 402 { 403 vm_object_t ksobj; 404 vm_offset_t ks; 405 vm_page_t m, ma[KSTACK_MAX_PAGES]; 406 int i; 407 408 /* Bounds check */ 409 if (pages <= 1) 410 pages = KSTACK_PAGES; 411 else if (pages > KSTACK_MAX_PAGES) 412 pages = KSTACK_MAX_PAGES; 413 /* 414 * Allocate an object for the kstack. 415 */ 416 ksobj = vm_object_allocate(OBJT_DEFAULT, pages); 417 td->td_kstack_obj = ksobj; 418 /* 419 * Get a kernel virtual address for this thread's kstack. 420 */ 421 ks = kmem_alloc_nofault(kernel_map, 422 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 423 if (ks == 0) 424 panic("vm_thread_new: kstack allocation failed"); 425 if (KSTACK_GUARD_PAGES != 0) { 426 pmap_qremove(ks, KSTACK_GUARD_PAGES); 427 ks += KSTACK_GUARD_PAGES * PAGE_SIZE; 428 } 429 td->td_kstack = ks; 430 /* 431 * Knowing the number of pages allocated is useful when you 432 * want to deallocate them. 433 */ 434 td->td_kstack_pages = pages; 435 /* 436 * For the length of the stack, link in a real page of ram for each 437 * page of stack. 438 */ 439 VM_OBJECT_LOCK(ksobj); 440 for (i = 0; i < pages; i++) { 441 /* 442 * Get a kernel stack page. 443 */ 444 m = vm_page_grab(ksobj, i, 445 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 446 ma[i] = m; 447 vm_page_lock_queues(); 448 vm_page_wakeup(m); 449 m->valid = VM_PAGE_BITS_ALL; 450 vm_page_unlock_queues(); 451 } 452 VM_OBJECT_UNLOCK(ksobj); 453 pmap_qenter(ks, ma, pages); 454 } 455 456 /* 457 * Dispose of a thread's kernel stack. 458 */ 459 void 460 vm_thread_dispose(struct thread *td) 461 { 462 vm_object_t ksobj; 463 vm_offset_t ks; 464 vm_page_t m; 465 int i, pages; 466 467 pages = td->td_kstack_pages; 468 ksobj = td->td_kstack_obj; 469 ks = td->td_kstack; 470 pmap_qremove(ks, pages); 471 VM_OBJECT_LOCK(ksobj); 472 for (i = 0; i < pages; i++) { 473 m = vm_page_lookup(ksobj, i); 474 if (m == NULL) 475 panic("vm_thread_dispose: kstack already missing?"); 476 vm_page_lock_queues(); 477 vm_page_busy(m); 478 vm_page_unwire(m, 0); 479 vm_page_free(m); 480 vm_page_unlock_queues(); 481 } 482 VM_OBJECT_UNLOCK(ksobj); 483 vm_object_deallocate(ksobj); 484 kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 485 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 486 } 487 488 /* 489 * Allow a thread's kernel stack to be paged out. 490 */ 491 void 492 vm_thread_swapout(struct thread *td) 493 { 494 vm_object_t ksobj; 495 vm_page_t m; 496 int i, pages; 497 498 cpu_thread_swapout(td); 499 pages = td->td_kstack_pages; 500 ksobj = td->td_kstack_obj; 501 pmap_qremove(td->td_kstack, pages); 502 VM_OBJECT_LOCK(ksobj); 503 for (i = 0; i < pages; i++) { 504 m = vm_page_lookup(ksobj, i); 505 if (m == NULL) 506 panic("vm_thread_swapout: kstack already missing?"); 507 vm_page_lock_queues(); 508 vm_page_dirty(m); 509 vm_page_unwire(m, 0); 510 vm_page_unlock_queues(); 511 } 512 VM_OBJECT_UNLOCK(ksobj); 513 } 514 515 /* 516 * Bring the kernel stack for a specified thread back in. 517 */ 518 void 519 vm_thread_swapin(struct thread *td) 520 { 521 vm_object_t ksobj; 522 vm_page_t m, ma[KSTACK_MAX_PAGES]; 523 int i, pages, rv; 524 525 pages = td->td_kstack_pages; 526 ksobj = td->td_kstack_obj; 527 VM_OBJECT_LOCK(ksobj); 528 for (i = 0; i < pages; i++) { 529 m = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 530 if (m->valid != VM_PAGE_BITS_ALL) { 531 rv = vm_pager_get_pages(ksobj, &m, 1, 0); 532 if (rv != VM_PAGER_OK) 533 panic("vm_thread_swapin: cannot get kstack for proc: %d", td->td_proc->p_pid); 534 m = vm_page_lookup(ksobj, i); 535 m->valid = VM_PAGE_BITS_ALL; 536 } 537 ma[i] = m; 538 vm_page_lock_queues(); 539 vm_page_wire(m); 540 vm_page_wakeup(m); 541 vm_page_unlock_queues(); 542 } 543 VM_OBJECT_UNLOCK(ksobj); 544 pmap_qenter(td->td_kstack, ma, pages); 545 cpu_thread_swapin(td); 546 } 547 548 /* 549 * Set up a variable-sized alternate kstack. 550 */ 551 void 552 vm_thread_new_altkstack(struct thread *td, int pages) 553 { 554 555 td->td_altkstack = td->td_kstack; 556 td->td_altkstack_obj = td->td_kstack_obj; 557 td->td_altkstack_pages = td->td_kstack_pages; 558 559 vm_thread_new(td, pages); 560 } 561 562 /* 563 * Restore the original kstack. 564 */ 565 void 566 vm_thread_dispose_altkstack(struct thread *td) 567 { 568 569 vm_thread_dispose(td); 570 571 td->td_kstack = td->td_altkstack; 572 td->td_kstack_obj = td->td_altkstack_obj; 573 td->td_kstack_pages = td->td_altkstack_pages; 574 td->td_altkstack = 0; 575 td->td_altkstack_obj = NULL; 576 td->td_altkstack_pages = 0; 577 } 578 579 /* 580 * Implement fork's actions on an address space. 581 * Here we arrange for the address space to be copied or referenced, 582 * allocate a user struct (pcb and kernel stack), then call the 583 * machine-dependent layer to fill those in and make the new process 584 * ready to run. The new process is set up so that it returns directly 585 * to user mode to avoid stack copying and relocation problems. 586 */ 587 void 588 vm_forkproc(td, p2, td2, flags) 589 struct thread *td; 590 struct proc *p2; 591 struct thread *td2; 592 int flags; 593 { 594 struct proc *p1 = td->td_proc; 595 struct user *up; 596 597 GIANT_REQUIRED; 598 599 if ((flags & RFPROC) == 0) { 600 /* 601 * Divorce the memory, if it is shared, essentially 602 * this changes shared memory amongst threads, into 603 * COW locally. 604 */ 605 if ((flags & RFMEM) == 0) { 606 if (p1->p_vmspace->vm_refcnt > 1) { 607 vmspace_unshare(p1); 608 } 609 } 610 cpu_fork(td, p2, td2, flags); 611 return; 612 } 613 614 if (flags & RFMEM) { 615 p2->p_vmspace = p1->p_vmspace; 616 p1->p_vmspace->vm_refcnt++; 617 } 618 619 while (vm_page_count_severe()) { 620 VM_WAIT; 621 } 622 623 if ((flags & RFMEM) == 0) { 624 p2->p_vmspace = vmspace_fork(p1->p_vmspace); 625 626 pmap_pinit2(vmspace_pmap(p2->p_vmspace)); 627 628 if (p1->p_vmspace->vm_shm) 629 shmfork(p1, p2); 630 } 631 632 /* XXXKSE this is unsatisfactory but should be adequate */ 633 up = p2->p_uarea; 634 MPASS(p2->p_sigacts != NULL); 635 636 /* 637 * p_stats currently points at fields in the user struct 638 * but not at &u, instead at p_addr. Copy parts of 639 * p_stats; zero the rest of p_stats (statistics). 640 */ 641 p2->p_stats = &up->u_stats; 642 bzero(&up->u_stats.pstat_startzero, 643 (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - 644 (caddr_t) &up->u_stats.pstat_startzero)); 645 bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, 646 ((caddr_t) &up->u_stats.pstat_endcopy - 647 (caddr_t) &up->u_stats.pstat_startcopy)); 648 649 /* 650 * cpu_fork will copy and update the pcb, set up the kernel stack, 651 * and make the child ready to run. 652 */ 653 cpu_fork(td, p2, td2, flags); 654 } 655 656 /* 657 * Called after process has been wait(2)'ed apon and is being reaped. 658 * The idea is to reclaim resources that we could not reclaim while 659 * the process was still executing. 660 */ 661 void 662 vm_waitproc(p) 663 struct proc *p; 664 { 665 666 GIANT_REQUIRED; 667 vmspace_exitfree(p); /* and clean-out the vmspace */ 668 } 669 670 /* 671 * Set default limits for VM system. 672 * Called for proc 0, and then inherited by all others. 673 * 674 * XXX should probably act directly on proc0. 675 */ 676 static void 677 vm_init_limits(udata) 678 void *udata; 679 { 680 struct proc *p = udata; 681 int rss_limit; 682 683 /* 684 * Set up the initial limits on process VM. Set the maximum resident 685 * set size to be half of (reasonably) available memory. Since this 686 * is a soft limit, it comes into effect only when the system is out 687 * of memory - half of main memory helps to favor smaller processes, 688 * and reduces thrashing of the object cache. 689 */ 690 p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; 691 p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; 692 p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; 693 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; 694 /* limit the limit to no less than 2MB */ 695 rss_limit = max(cnt.v_free_count, 512); 696 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); 697 p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; 698 } 699 700 void 701 faultin(p) 702 struct proc *p; 703 { 704 #ifdef NO_SWAPPING 705 706 PROC_LOCK_ASSERT(p, MA_OWNED); 707 if ((p->p_sflag & PS_INMEM) == 0) 708 panic("faultin: proc swapped out with NO_SWAPPING!"); 709 #else /* !NO_SWAPPING */ 710 struct thread *td; 711 712 GIANT_REQUIRED; 713 PROC_LOCK_ASSERT(p, MA_OWNED); 714 /* 715 * If another process is swapping in this process, 716 * just wait until it finishes. 717 */ 718 if (p->p_sflag & PS_SWAPPINGIN) 719 msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); 720 else if ((p->p_sflag & PS_INMEM) == 0) { 721 /* 722 * Don't let another thread swap process p out while we are 723 * busy swapping it in. 724 */ 725 ++p->p_lock; 726 mtx_lock_spin(&sched_lock); 727 p->p_sflag |= PS_SWAPPINGIN; 728 mtx_unlock_spin(&sched_lock); 729 PROC_UNLOCK(p); 730 731 vm_proc_swapin(p); 732 FOREACH_THREAD_IN_PROC(p, td) 733 vm_thread_swapin(td); 734 735 PROC_LOCK(p); 736 mtx_lock_spin(&sched_lock); 737 p->p_sflag &= ~PS_SWAPPINGIN; 738 p->p_sflag |= PS_INMEM; 739 FOREACH_THREAD_IN_PROC(p, td) { 740 TD_CLR_SWAPPED(td); 741 if (TD_CAN_RUN(td)) 742 setrunnable(td); 743 } 744 mtx_unlock_spin(&sched_lock); 745 746 wakeup(&p->p_sflag); 747 748 /* Allow other threads to swap p out now. */ 749 --p->p_lock; 750 } 751 #endif /* NO_SWAPPING */ 752 } 753 754 /* 755 * This swapin algorithm attempts to swap-in processes only if there 756 * is enough space for them. Of course, if a process waits for a long 757 * time, it will be swapped in anyway. 758 * 759 * XXXKSE - process with the thread with highest priority counts.. 760 * 761 * Giant is still held at this point, to be released in tsleep. 762 */ 763 /* ARGSUSED*/ 764 static void 765 scheduler(dummy) 766 void *dummy; 767 { 768 struct proc *p; 769 struct thread *td; 770 int pri; 771 struct proc *pp; 772 int ppri; 773 774 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 775 /* GIANT_REQUIRED */ 776 777 loop: 778 if (vm_page_count_min()) { 779 VM_WAIT; 780 goto loop; 781 } 782 783 pp = NULL; 784 ppri = INT_MIN; 785 sx_slock(&allproc_lock); 786 FOREACH_PROC_IN_SYSTEM(p) { 787 struct ksegrp *kg; 788 if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { 789 continue; 790 } 791 mtx_lock_spin(&sched_lock); 792 FOREACH_THREAD_IN_PROC(p, td) { 793 /* 794 * An otherwise runnable thread of a process 795 * swapped out has only the TDI_SWAPPED bit set. 796 * 797 */ 798 if (td->td_inhibitors == TDI_SWAPPED) { 799 kg = td->td_ksegrp; 800 pri = p->p_swtime + kg->kg_slptime; 801 if ((p->p_sflag & PS_SWAPINREQ) == 0) { 802 pri -= kg->kg_nice * 8; 803 } 804 805 /* 806 * if this ksegrp is higher priority 807 * and there is enough space, then select 808 * this process instead of the previous 809 * selection. 810 */ 811 if (pri > ppri) { 812 pp = p; 813 ppri = pri; 814 } 815 } 816 } 817 mtx_unlock_spin(&sched_lock); 818 } 819 sx_sunlock(&allproc_lock); 820 821 /* 822 * Nothing to do, back to sleep. 823 */ 824 if ((p = pp) == NULL) { 825 tsleep(&proc0, PVM, "sched", maxslp * hz / 2); 826 goto loop; 827 } 828 PROC_LOCK(p); 829 830 /* 831 * Another process may be bringing or may have already 832 * brought this process in while we traverse all threads. 833 * Or, this process may even be being swapped out again. 834 */ 835 if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { 836 PROC_UNLOCK(p); 837 goto loop; 838 } 839 840 mtx_lock_spin(&sched_lock); 841 p->p_sflag &= ~PS_SWAPINREQ; 842 mtx_unlock_spin(&sched_lock); 843 844 /* 845 * We would like to bring someone in. (only if there is space). 846 * [What checks the space? ] 847 */ 848 faultin(p); 849 PROC_UNLOCK(p); 850 mtx_lock_spin(&sched_lock); 851 p->p_swtime = 0; 852 mtx_unlock_spin(&sched_lock); 853 goto loop; 854 } 855 856 #ifndef NO_SWAPPING 857 858 /* 859 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 860 */ 861 static int swap_idle_threshold1 = 2; 862 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW, 863 &swap_idle_threshold1, 0, "Guaranteed swapped in time for a process"); 864 865 /* 866 * Swap_idle_threshold2 is the time that a process can be idle before 867 * it will be swapped out, if idle swapping is enabled. 868 */ 869 static int swap_idle_threshold2 = 10; 870 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW, 871 &swap_idle_threshold2, 0, "Time before a process will be swapped out"); 872 873 /* 874 * Swapout is driven by the pageout daemon. Very simple, we find eligible 875 * procs and unwire their u-areas. We try to always "swap" at least one 876 * process in case we need the room for a swapin. 877 * If any procs have been sleeping/stopped for at least maxslp seconds, 878 * they are swapped. Else, we swap the longest-sleeping or stopped process, 879 * if any, otherwise the longest-resident process. 880 */ 881 void 882 swapout_procs(action) 883 int action; 884 { 885 struct proc *p; 886 struct thread *td; 887 struct ksegrp *kg; 888 int didswap = 0; 889 890 GIANT_REQUIRED; 891 892 retry: 893 sx_slock(&allproc_lock); 894 FOREACH_PROC_IN_SYSTEM(p) { 895 struct vmspace *vm; 896 int minslptime = 100000; 897 898 /* 899 * Watch out for a process in 900 * creation. It may have no 901 * address space or lock yet. 902 */ 903 mtx_lock_spin(&sched_lock); 904 if (p->p_state == PRS_NEW) { 905 mtx_unlock_spin(&sched_lock); 906 continue; 907 } 908 mtx_unlock_spin(&sched_lock); 909 910 /* 911 * An aio daemon switches its 912 * address space while running. 913 * Perform a quick check whether 914 * a process has P_SYSTEM. 915 */ 916 if ((p->p_flag & P_SYSTEM) != 0) 917 continue; 918 919 /* 920 * Do not swapout a process that 921 * is waiting for VM data 922 * structures as there is a possible 923 * deadlock. Test this first as 924 * this may block. 925 * 926 * Lock the map until swapout 927 * finishes, or a thread of this 928 * process may attempt to alter 929 * the map. 930 */ 931 PROC_LOCK(p); 932 vm = p->p_vmspace; 933 KASSERT(vm != NULL, 934 ("swapout_procs: a process has no address space")); 935 ++vm->vm_refcnt; 936 PROC_UNLOCK(p); 937 if (!vm_map_trylock(&vm->vm_map)) 938 goto nextproc1; 939 940 PROC_LOCK(p); 941 if (p->p_lock != 0 || 942 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) 943 ) != 0) { 944 goto nextproc2; 945 } 946 /* 947 * only aiod changes vmspace, however it will be 948 * skipped because of the if statement above checking 949 * for P_SYSTEM 950 */ 951 if ((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) != PS_INMEM) 952 goto nextproc2; 953 954 switch (p->p_state) { 955 default: 956 /* Don't swap out processes in any sort 957 * of 'special' state. */ 958 break; 959 960 case PRS_NORMAL: 961 mtx_lock_spin(&sched_lock); 962 /* 963 * do not swapout a realtime process 964 * Check all the thread groups.. 965 */ 966 FOREACH_KSEGRP_IN_PROC(p, kg) { 967 if (PRI_IS_REALTIME(kg->kg_pri_class)) 968 goto nextproc; 969 970 /* 971 * Guarantee swap_idle_threshold1 972 * time in memory. 973 */ 974 if (kg->kg_slptime < swap_idle_threshold1) 975 goto nextproc; 976 977 /* 978 * Do not swapout a process if it is 979 * waiting on a critical event of some 980 * kind or there is a thread whose 981 * pageable memory may be accessed. 982 * 983 * This could be refined to support 984 * swapping out a thread. 985 */ 986 FOREACH_THREAD_IN_GROUP(kg, td) { 987 if ((td->td_priority) < PSOCK || 988 !thread_safetoswapout(td)) 989 goto nextproc; 990 } 991 /* 992 * If the system is under memory stress, 993 * or if we are swapping 994 * idle processes >= swap_idle_threshold2, 995 * then swap the process out. 996 */ 997 if (((action & VM_SWAP_NORMAL) == 0) && 998 (((action & VM_SWAP_IDLE) == 0) || 999 (kg->kg_slptime < swap_idle_threshold2))) 1000 goto nextproc; 1001 1002 if (minslptime > kg->kg_slptime) 1003 minslptime = kg->kg_slptime; 1004 } 1005 1006 /* 1007 * If the process has been asleep for awhile and had 1008 * most of its pages taken away already, swap it out. 1009 */ 1010 if ((action & VM_SWAP_NORMAL) || 1011 ((action & VM_SWAP_IDLE) && 1012 (minslptime > swap_idle_threshold2))) { 1013 swapout(p); 1014 didswap++; 1015 mtx_unlock_spin(&sched_lock); 1016 PROC_UNLOCK(p); 1017 vm_map_unlock(&vm->vm_map); 1018 vmspace_free(vm); 1019 sx_sunlock(&allproc_lock); 1020 goto retry; 1021 } 1022 nextproc: 1023 mtx_unlock_spin(&sched_lock); 1024 } 1025 nextproc2: 1026 PROC_UNLOCK(p); 1027 vm_map_unlock(&vm->vm_map); 1028 nextproc1: 1029 vmspace_free(vm); 1030 continue; 1031 } 1032 sx_sunlock(&allproc_lock); 1033 /* 1034 * If we swapped something out, and another process needed memory, 1035 * then wakeup the sched process. 1036 */ 1037 if (didswap) 1038 wakeup(&proc0); 1039 } 1040 1041 static void 1042 swapout(p) 1043 struct proc *p; 1044 { 1045 struct thread *td; 1046 1047 PROC_LOCK_ASSERT(p, MA_OWNED); 1048 mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); 1049 #if defined(SWAP_DEBUG) 1050 printf("swapping out %d\n", p->p_pid); 1051 #endif 1052 1053 /* 1054 * The states of this process and its threads may have changed 1055 * by now. Assuming that there is only one pageout daemon thread, 1056 * this process should still be in memory. 1057 */ 1058 KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) == PS_INMEM, 1059 ("swapout: lost a swapout race?")); 1060 1061 #if defined(INVARIANTS) 1062 /* 1063 * Make sure that all threads are safe to be swapped out. 1064 * 1065 * Alternatively, we could swap out only safe threads. 1066 */ 1067 FOREACH_THREAD_IN_PROC(p, td) { 1068 KASSERT(thread_safetoswapout(td), 1069 ("swapout: there is a thread not safe for swapout")); 1070 } 1071 #endif /* INVARIANTS */ 1072 1073 ++p->p_stats->p_ru.ru_nswap; 1074 /* 1075 * remember the process resident count 1076 */ 1077 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 1078 1079 p->p_sflag &= ~PS_INMEM; 1080 p->p_sflag |= PS_SWAPPINGOUT; 1081 PROC_UNLOCK(p); 1082 FOREACH_THREAD_IN_PROC(p, td) 1083 TD_SET_SWAPPED(td); 1084 mtx_unlock_spin(&sched_lock); 1085 1086 vm_proc_swapout(p); 1087 FOREACH_THREAD_IN_PROC(p, td) 1088 vm_thread_swapout(td); 1089 1090 PROC_LOCK(p); 1091 mtx_lock_spin(&sched_lock); 1092 p->p_sflag &= ~PS_SWAPPINGOUT; 1093 p->p_swtime = 0; 1094 } 1095 #endif /* !NO_SWAPPING */ 1096