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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Permission to use, copy, modify and distribute this software and 39 * its documentation is hereby granted, provided that both the copyright 40 * notice and this permission notice appear in all copies of the 41 * software, derivative works or modified versions, and any portions 42 * thereof, and that both notices appear in supporting documentation. 43 * 44 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 45 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 46 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 47 * 48 * Carnegie Mellon requests users of this software to return to 49 * 50 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 51 * School of Computer Science 52 * Carnegie Mellon University 53 * Pittsburgh PA 15213-3890 54 * 55 * any improvements or extensions that they make and grant Carnegie the 56 * rights to redistribute these changes. 57 */ 58 59 #include <sys/cdefs.h> 60 __FBSDID("$FreeBSD$"); 61 62 #include "opt_vm.h" 63 #include "opt_kstack_pages.h" 64 #include "opt_kstack_max_pages.h" 65 66 #include <sys/param.h> 67 #include <sys/systm.h> 68 #include <sys/limits.h> 69 #include <sys/lock.h> 70 #include <sys/mutex.h> 71 #include <sys/proc.h> 72 #include <sys/racct.h> 73 #include <sys/resourcevar.h> 74 #include <sys/sched.h> 75 #include <sys/sf_buf.h> 76 #include <sys/shm.h> 77 #include <sys/vmmeter.h> 78 #include <sys/sx.h> 79 #include <sys/sysctl.h> 80 81 #include <sys/eventhandler.h> 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 /* 99 * System initialization 100 * 101 * THIS MUST BE THE LAST INITIALIZATION ITEM!!! 102 * 103 * Note: run scheduling should be divorced from the vm system. 104 */ 105 static void scheduler(void *); 106 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, scheduler, NULL); 107 108 #ifndef NO_SWAPPING 109 static int swapout(struct proc *); 110 static void swapclear(struct proc *); 111 static void vm_thread_swapin(struct thread *td); 112 static void vm_thread_swapout(struct thread *td); 113 #endif 114 115 /* 116 * MPSAFE 117 * 118 * WARNING! This code calls vm_map_check_protection() which only checks 119 * the associated vm_map_entry range. It does not determine whether the 120 * contents of the memory is actually readable or writable. In most cases 121 * just checking the vm_map_entry is sufficient within the kernel's address 122 * space. 123 */ 124 int 125 kernacc(addr, len, rw) 126 void *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)); 135 136 if ((vm_offset_t)addr + len > kernel_map->max_offset || 137 (vm_offset_t)addr + len < (vm_offset_t)addr) 138 return (FALSE); 139 140 prot = rw; 141 saddr = trunc_page((vm_offset_t)addr); 142 eaddr = round_page((vm_offset_t)addr + len); 143 vm_map_lock_read(kernel_map); 144 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); 145 vm_map_unlock_read(kernel_map); 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 vm_map_lock_read(map); 176 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), 177 round_page((vm_offset_t)addr + len), prot); 178 vm_map_unlock_read(map); 179 return (rv == TRUE); 180 } 181 182 int 183 vslock(void *addr, size_t len) 184 { 185 vm_offset_t end, last, start; 186 unsigned long nsize; 187 vm_size_t npages; 188 int error; 189 190 last = (vm_offset_t)addr + len; 191 start = trunc_page((vm_offset_t)addr); 192 end = round_page(last); 193 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr) 194 return (EINVAL); 195 npages = atop(end - start); 196 if (npages > vm_page_max_wired) 197 return (ENOMEM); 198 PROC_LOCK(curproc); 199 nsize = ptoa(npages + 200 pmap_wired_count(vm_map_pmap(&curproc->p_vmspace->vm_map))); 201 if (nsize > lim_cur(curproc, RLIMIT_MEMLOCK)) { 202 PROC_UNLOCK(curproc); 203 return (ENOMEM); 204 } 205 if (racct_set(curproc, RACCT_MEMLOCK, nsize)) { 206 PROC_UNLOCK(curproc); 207 return (ENOMEM); 208 } 209 PROC_UNLOCK(curproc); 210 #if 0 211 /* 212 * XXX - not yet 213 * 214 * The limit for transient usage of wired pages should be 215 * larger than for "permanent" wired pages (mlock()). 216 * 217 * Also, the sysctl code, which is the only present user 218 * of vslock(), does a hard loop on EAGAIN. 219 */ 220 if (npages + cnt.v_wire_count > vm_page_max_wired) 221 return (EAGAIN); 222 #endif 223 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end, 224 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 225 if (error != KERN_SUCCESS) { 226 PROC_LOCK(curproc); 227 racct_set(curproc, RACCT_MEMLOCK, 228 ptoa(pmap_wired_count(vm_map_pmap(&curproc->p_vmspace->vm_map)))); 229 PROC_UNLOCK(curproc); 230 } 231 /* 232 * Return EFAULT on error to match copy{in,out}() behaviour 233 * rather than returning ENOMEM like mlock() would. 234 */ 235 return (error == KERN_SUCCESS ? 0 : EFAULT); 236 } 237 238 void 239 vsunlock(void *addr, size_t len) 240 { 241 242 /* Rely on the parameter sanity checks performed by vslock(). */ 243 (void)vm_map_unwire(&curproc->p_vmspace->vm_map, 244 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 245 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); 246 247 PROC_LOCK(curproc); 248 racct_set(curproc, RACCT_MEMLOCK, 249 ptoa(pmap_wired_count(vm_map_pmap(&curproc->p_vmspace->vm_map)))); 250 PROC_UNLOCK(curproc); 251 } 252 253 /* 254 * Pin the page contained within the given object at the given offset. If the 255 * page is not resident, allocate and load it using the given object's pager. 256 * Return the pinned page if successful; otherwise, return NULL. 257 */ 258 static vm_page_t 259 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset) 260 { 261 vm_page_t m, ma[1]; 262 vm_pindex_t pindex; 263 int rv; 264 265 VM_OBJECT_LOCK(object); 266 pindex = OFF_TO_IDX(offset); 267 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); 268 if (m->valid != VM_PAGE_BITS_ALL) { 269 ma[0] = m; 270 rv = vm_pager_get_pages(object, ma, 1, 0); 271 m = vm_page_lookup(object, pindex); 272 if (m == NULL) 273 goto out; 274 if (rv != VM_PAGER_OK) { 275 vm_page_lock(m); 276 vm_page_free(m); 277 vm_page_unlock(m); 278 m = NULL; 279 goto out; 280 } 281 } 282 vm_page_lock(m); 283 vm_page_hold(m); 284 vm_page_unlock(m); 285 vm_page_wakeup(m); 286 out: 287 VM_OBJECT_UNLOCK(object); 288 return (m); 289 } 290 291 /* 292 * Return a CPU private mapping to the page at the given offset within the 293 * given object. The page is pinned before it is mapped. 294 */ 295 struct sf_buf * 296 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) 297 { 298 vm_page_t m; 299 300 m = vm_imgact_hold_page(object, offset); 301 if (m == NULL) 302 return (NULL); 303 sched_pin(); 304 return (sf_buf_alloc(m, SFB_CPUPRIVATE)); 305 } 306 307 /* 308 * Destroy the given CPU private mapping and unpin the page that it mapped. 309 */ 310 void 311 vm_imgact_unmap_page(struct sf_buf *sf) 312 { 313 vm_page_t m; 314 315 m = sf_buf_page(sf); 316 sf_buf_free(sf); 317 sched_unpin(); 318 vm_page_lock(m); 319 vm_page_unhold(m); 320 vm_page_unlock(m); 321 } 322 323 void 324 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz) 325 { 326 327 pmap_sync_icache(map->pmap, va, sz); 328 } 329 330 struct kstack_cache_entry { 331 vm_object_t ksobj; 332 struct kstack_cache_entry *next_ks_entry; 333 }; 334 335 static struct kstack_cache_entry *kstack_cache; 336 static int kstack_cache_size = 128; 337 static int kstacks; 338 static struct mtx kstack_cache_mtx; 339 SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0, 340 ""); 341 SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0, 342 ""); 343 344 #ifndef KSTACK_MAX_PAGES 345 #define KSTACK_MAX_PAGES 32 346 #endif 347 348 /* 349 * Create the kernel stack (including pcb for i386) for a new thread. 350 * This routine directly affects the fork perf for a process and 351 * create performance for a thread. 352 */ 353 int 354 vm_thread_new(struct thread *td, int pages) 355 { 356 vm_object_t ksobj; 357 vm_offset_t ks; 358 vm_page_t m, ma[KSTACK_MAX_PAGES]; 359 struct kstack_cache_entry *ks_ce; 360 int i; 361 362 /* Bounds check */ 363 if (pages <= 1) 364 pages = KSTACK_PAGES; 365 else if (pages > KSTACK_MAX_PAGES) 366 pages = KSTACK_MAX_PAGES; 367 368 if (pages == KSTACK_PAGES) { 369 mtx_lock(&kstack_cache_mtx); 370 if (kstack_cache != NULL) { 371 ks_ce = kstack_cache; 372 kstack_cache = ks_ce->next_ks_entry; 373 mtx_unlock(&kstack_cache_mtx); 374 375 td->td_kstack_obj = ks_ce->ksobj; 376 td->td_kstack = (vm_offset_t)ks_ce; 377 td->td_kstack_pages = KSTACK_PAGES; 378 return (1); 379 } 380 mtx_unlock(&kstack_cache_mtx); 381 } 382 383 /* 384 * Allocate an object for the kstack. 385 */ 386 ksobj = vm_object_allocate(OBJT_DEFAULT, pages); 387 388 /* 389 * Get a kernel virtual address for this thread's kstack. 390 */ 391 #if defined(__mips__) 392 /* 393 * We need to align the kstack's mapped address to fit within 394 * a single TLB entry. 395 */ 396 ks = kmem_alloc_nofault_space(kernel_map, 397 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE, VMFS_TLB_ALIGNED_SPACE); 398 #else 399 ks = kmem_alloc_nofault(kernel_map, 400 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 401 #endif 402 if (ks == 0) { 403 printf("vm_thread_new: kstack allocation failed\n"); 404 vm_object_deallocate(ksobj); 405 return (0); 406 } 407 408 atomic_add_int(&kstacks, 1); 409 if (KSTACK_GUARD_PAGES != 0) { 410 pmap_qremove(ks, KSTACK_GUARD_PAGES); 411 ks += KSTACK_GUARD_PAGES * PAGE_SIZE; 412 } 413 td->td_kstack_obj = ksobj; 414 td->td_kstack = ks; 415 /* 416 * Knowing the number of pages allocated is useful when you 417 * want to deallocate them. 418 */ 419 td->td_kstack_pages = pages; 420 /* 421 * For the length of the stack, link in a real page of ram for each 422 * page of stack. 423 */ 424 VM_OBJECT_LOCK(ksobj); 425 for (i = 0; i < pages; i++) { 426 /* 427 * Get a kernel stack page. 428 */ 429 m = vm_page_grab(ksobj, i, VM_ALLOC_NOBUSY | 430 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); 431 ma[i] = m; 432 m->valid = VM_PAGE_BITS_ALL; 433 } 434 VM_OBJECT_UNLOCK(ksobj); 435 pmap_qenter(ks, ma, pages); 436 return (1); 437 } 438 439 static void 440 vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) 441 { 442 vm_page_t m; 443 int i; 444 445 atomic_add_int(&kstacks, -1); 446 pmap_qremove(ks, pages); 447 VM_OBJECT_LOCK(ksobj); 448 for (i = 0; i < pages; i++) { 449 m = vm_page_lookup(ksobj, i); 450 if (m == NULL) 451 panic("vm_thread_dispose: kstack already missing?"); 452 vm_page_lock(m); 453 vm_page_unwire(m, 0); 454 vm_page_free(m); 455 vm_page_unlock(m); 456 } 457 VM_OBJECT_UNLOCK(ksobj); 458 vm_object_deallocate(ksobj); 459 kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), 460 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); 461 } 462 463 /* 464 * Dispose of a thread's kernel stack. 465 */ 466 void 467 vm_thread_dispose(struct thread *td) 468 { 469 vm_object_t ksobj; 470 vm_offset_t ks; 471 struct kstack_cache_entry *ks_ce; 472 int pages; 473 474 pages = td->td_kstack_pages; 475 ksobj = td->td_kstack_obj; 476 ks = td->td_kstack; 477 td->td_kstack = 0; 478 td->td_kstack_pages = 0; 479 if (pages == KSTACK_PAGES && kstacks <= kstack_cache_size) { 480 ks_ce = (struct kstack_cache_entry *)ks; 481 ks_ce->ksobj = ksobj; 482 mtx_lock(&kstack_cache_mtx); 483 ks_ce->next_ks_entry = kstack_cache; 484 kstack_cache = ks_ce; 485 mtx_unlock(&kstack_cache_mtx); 486 return; 487 } 488 vm_thread_stack_dispose(ksobj, ks, pages); 489 } 490 491 static void 492 vm_thread_stack_lowmem(void *nulll) 493 { 494 struct kstack_cache_entry *ks_ce, *ks_ce1; 495 496 mtx_lock(&kstack_cache_mtx); 497 ks_ce = kstack_cache; 498 kstack_cache = NULL; 499 mtx_unlock(&kstack_cache_mtx); 500 501 while (ks_ce != NULL) { 502 ks_ce1 = ks_ce; 503 ks_ce = ks_ce->next_ks_entry; 504 505 vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1, 506 KSTACK_PAGES); 507 } 508 } 509 510 static void 511 kstack_cache_init(void *nulll) 512 { 513 514 EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL, 515 EVENTHANDLER_PRI_ANY); 516 } 517 518 MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF); 519 SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); 520 521 #ifndef NO_SWAPPING 522 /* 523 * Allow a thread's kernel stack to be paged out. 524 */ 525 static void 526 vm_thread_swapout(struct thread *td) 527 { 528 vm_object_t ksobj; 529 vm_page_t m; 530 int i, pages; 531 532 cpu_thread_swapout(td); 533 pages = td->td_kstack_pages; 534 ksobj = td->td_kstack_obj; 535 pmap_qremove(td->td_kstack, pages); 536 VM_OBJECT_LOCK(ksobj); 537 for (i = 0; i < pages; i++) { 538 m = vm_page_lookup(ksobj, i); 539 if (m == NULL) 540 panic("vm_thread_swapout: kstack already missing?"); 541 vm_page_dirty(m); 542 vm_page_lock(m); 543 vm_page_unwire(m, 0); 544 vm_page_unlock(m); 545 } 546 VM_OBJECT_UNLOCK(ksobj); 547 } 548 549 /* 550 * Bring the kernel stack for a specified thread back in. 551 */ 552 static void 553 vm_thread_swapin(struct thread *td) 554 { 555 vm_object_t ksobj; 556 vm_page_t ma[KSTACK_MAX_PAGES]; 557 int i, j, k, pages, rv; 558 559 pages = td->td_kstack_pages; 560 ksobj = td->td_kstack_obj; 561 VM_OBJECT_LOCK(ksobj); 562 for (i = 0; i < pages; i++) 563 ma[i] = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY | 564 VM_ALLOC_WIRED); 565 for (i = 0; i < pages; i++) { 566 if (ma[i]->valid != VM_PAGE_BITS_ALL) { 567 KASSERT(ma[i]->oflags & VPO_BUSY, 568 ("lost busy 1")); 569 vm_object_pip_add(ksobj, 1); 570 for (j = i + 1; j < pages; j++) { 571 KASSERT(ma[j]->valid == VM_PAGE_BITS_ALL || 572 (ma[j]->oflags & VPO_BUSY), 573 ("lost busy 2")); 574 if (ma[j]->valid == VM_PAGE_BITS_ALL) 575 break; 576 } 577 rv = vm_pager_get_pages(ksobj, ma + i, j - i, 0); 578 if (rv != VM_PAGER_OK) 579 panic("vm_thread_swapin: cannot get kstack for proc: %d", 580 td->td_proc->p_pid); 581 vm_object_pip_wakeup(ksobj); 582 for (k = i; k < j; k++) 583 ma[k] = vm_page_lookup(ksobj, k); 584 vm_page_wakeup(ma[i]); 585 } else if (ma[i]->oflags & VPO_BUSY) 586 vm_page_wakeup(ma[i]); 587 } 588 VM_OBJECT_UNLOCK(ksobj); 589 pmap_qenter(td->td_kstack, ma, pages); 590 cpu_thread_swapin(td); 591 } 592 #endif /* !NO_SWAPPING */ 593 594 /* 595 * Implement fork's actions on an address space. 596 * Here we arrange for the address space to be copied or referenced, 597 * allocate a user struct (pcb and kernel stack), then call the 598 * machine-dependent layer to fill those in and make the new process 599 * ready to run. The new process is set up so that it returns directly 600 * to user mode to avoid stack copying and relocation problems. 601 */ 602 int 603 vm_forkproc(td, p2, td2, vm2, flags) 604 struct thread *td; 605 struct proc *p2; 606 struct thread *td2; 607 struct vmspace *vm2; 608 int flags; 609 { 610 struct proc *p1 = td->td_proc; 611 int error; 612 613 if ((flags & RFPROC) == 0) { 614 /* 615 * Divorce the memory, if it is shared, essentially 616 * this changes shared memory amongst threads, into 617 * COW locally. 618 */ 619 if ((flags & RFMEM) == 0) { 620 if (p1->p_vmspace->vm_refcnt > 1) { 621 error = vmspace_unshare(p1); 622 if (error) 623 return (error); 624 } 625 } 626 cpu_fork(td, p2, td2, flags); 627 return (0); 628 } 629 630 if (flags & RFMEM) { 631 p2->p_vmspace = p1->p_vmspace; 632 atomic_add_int(&p1->p_vmspace->vm_refcnt, 1); 633 } 634 635 while (vm_page_count_severe()) { 636 VM_WAIT; 637 } 638 639 if ((flags & RFMEM) == 0) { 640 p2->p_vmspace = vm2; 641 if (p1->p_vmspace->vm_shm) 642 shmfork(p1, p2); 643 } 644 645 /* 646 * cpu_fork will copy and update the pcb, set up the kernel stack, 647 * and make the child ready to run. 648 */ 649 cpu_fork(td, p2, td2, flags); 650 return (0); 651 } 652 653 /* 654 * Called after process has been wait(2)'ed apon and is being reaped. 655 * The idea is to reclaim resources that we could not reclaim while 656 * the process was still executing. 657 */ 658 void 659 vm_waitproc(p) 660 struct proc *p; 661 { 662 663 vmspace_exitfree(p); /* and clean-out the vmspace */ 664 } 665 666 void 667 faultin(p) 668 struct proc *p; 669 { 670 #ifdef NO_SWAPPING 671 672 PROC_LOCK_ASSERT(p, MA_OWNED); 673 if ((p->p_flag & P_INMEM) == 0) 674 panic("faultin: proc swapped out with NO_SWAPPING!"); 675 #else /* !NO_SWAPPING */ 676 struct thread *td; 677 678 PROC_LOCK_ASSERT(p, MA_OWNED); 679 /* 680 * If another process is swapping in this process, 681 * just wait until it finishes. 682 */ 683 if (p->p_flag & P_SWAPPINGIN) { 684 while (p->p_flag & P_SWAPPINGIN) 685 msleep(&p->p_flag, &p->p_mtx, PVM, "faultin", 0); 686 return; 687 } 688 if ((p->p_flag & P_INMEM) == 0) { 689 /* 690 * Don't let another thread swap process p out while we are 691 * busy swapping it in. 692 */ 693 ++p->p_lock; 694 p->p_flag |= P_SWAPPINGIN; 695 PROC_UNLOCK(p); 696 697 /* 698 * We hold no lock here because the list of threads 699 * can not change while all threads in the process are 700 * swapped out. 701 */ 702 FOREACH_THREAD_IN_PROC(p, td) 703 vm_thread_swapin(td); 704 PROC_LOCK(p); 705 swapclear(p); 706 p->p_swtick = ticks; 707 708 wakeup(&p->p_flag); 709 710 /* Allow other threads to swap p out now. */ 711 --p->p_lock; 712 } 713 #endif /* NO_SWAPPING */ 714 } 715 716 /* 717 * This swapin algorithm attempts to swap-in processes only if there 718 * is enough space for them. Of course, if a process waits for a long 719 * time, it will be swapped in anyway. 720 * 721 * Giant is held on entry. 722 */ 723 /* ARGSUSED*/ 724 static void 725 scheduler(dummy) 726 void *dummy; 727 { 728 struct proc *p; 729 struct thread *td; 730 struct proc *pp; 731 int slptime; 732 int swtime; 733 int ppri; 734 int pri; 735 736 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); 737 mtx_unlock(&Giant); 738 739 loop: 740 if (vm_page_count_min()) { 741 VM_WAIT; 742 goto loop; 743 } 744 745 pp = NULL; 746 ppri = INT_MIN; 747 sx_slock(&allproc_lock); 748 FOREACH_PROC_IN_SYSTEM(p) { 749 PROC_LOCK(p); 750 if (p->p_state == PRS_NEW || 751 p->p_flag & (P_SWAPPINGOUT | P_SWAPPINGIN | P_INMEM)) { 752 PROC_UNLOCK(p); 753 continue; 754 } 755 swtime = (ticks - p->p_swtick) / hz; 756 FOREACH_THREAD_IN_PROC(p, td) { 757 /* 758 * An otherwise runnable thread of a process 759 * swapped out has only the TDI_SWAPPED bit set. 760 * 761 */ 762 thread_lock(td); 763 if (td->td_inhibitors == TDI_SWAPPED) { 764 slptime = (ticks - td->td_slptick) / hz; 765 pri = swtime + slptime; 766 if ((td->td_flags & TDF_SWAPINREQ) == 0) 767 pri -= p->p_nice * 8; 768 /* 769 * if this thread is higher priority 770 * and there is enough space, then select 771 * this process instead of the previous 772 * selection. 773 */ 774 if (pri > ppri) { 775 pp = p; 776 ppri = pri; 777 } 778 } 779 thread_unlock(td); 780 } 781 PROC_UNLOCK(p); 782 } 783 sx_sunlock(&allproc_lock); 784 785 /* 786 * Nothing to do, back to sleep. 787 */ 788 if ((p = pp) == NULL) { 789 tsleep(&proc0, PVM, "sched", MAXSLP * hz / 2); 790 goto loop; 791 } 792 PROC_LOCK(p); 793 794 /* 795 * Another process may be bringing or may have already 796 * brought this process in while we traverse all threads. 797 * Or, this process may even be being swapped out again. 798 */ 799 if (p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) { 800 PROC_UNLOCK(p); 801 goto loop; 802 } 803 804 /* 805 * We would like to bring someone in. (only if there is space). 806 * [What checks the space? ] 807 */ 808 faultin(p); 809 PROC_UNLOCK(p); 810 goto loop; 811 } 812 813 void 814 kick_proc0(void) 815 { 816 817 wakeup(&proc0); 818 } 819 820 #ifndef NO_SWAPPING 821 822 /* 823 * Swap_idle_threshold1 is the guaranteed swapped in time for a process 824 */ 825 static int swap_idle_threshold1 = 2; 826 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW, 827 &swap_idle_threshold1, 0, "Guaranteed swapped in time for a process"); 828 829 /* 830 * Swap_idle_threshold2 is the time that a process can be idle before 831 * it will be swapped out, if idle swapping is enabled. 832 */ 833 static int swap_idle_threshold2 = 10; 834 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW, 835 &swap_idle_threshold2, 0, "Time before a process will be swapped out"); 836 837 /* 838 * First, if any processes have been sleeping or stopped for at least 839 * "swap_idle_threshold1" seconds, they are swapped out. If, however, 840 * no such processes exist, then the longest-sleeping or stopped 841 * process is swapped out. Finally, and only as a last resort, if 842 * there are no sleeping or stopped processes, the longest-resident 843 * process is swapped out. 844 */ 845 void 846 swapout_procs(action) 847 int action; 848 { 849 struct proc *p; 850 struct thread *td; 851 int didswap = 0; 852 853 retry: 854 sx_slock(&allproc_lock); 855 FOREACH_PROC_IN_SYSTEM(p) { 856 struct vmspace *vm; 857 int minslptime = 100000; 858 int slptime; 859 860 /* 861 * Watch out for a process in 862 * creation. It may have no 863 * address space or lock yet. 864 */ 865 if (p->p_state == PRS_NEW) 866 continue; 867 /* 868 * An aio daemon switches its 869 * address space while running. 870 * Perform a quick check whether 871 * a process has P_SYSTEM. 872 */ 873 if ((p->p_flag & P_SYSTEM) != 0) 874 continue; 875 /* 876 * Do not swapout a process that 877 * is waiting for VM data 878 * structures as there is a possible 879 * deadlock. Test this first as 880 * this may block. 881 * 882 * Lock the map until swapout 883 * finishes, or a thread of this 884 * process may attempt to alter 885 * the map. 886 */ 887 vm = vmspace_acquire_ref(p); 888 if (vm == NULL) 889 continue; 890 if (!vm_map_trylock(&vm->vm_map)) 891 goto nextproc1; 892 893 PROC_LOCK(p); 894 if (p->p_lock != 0 || 895 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) 896 ) != 0) { 897 goto nextproc; 898 } 899 /* 900 * only aiod changes vmspace, however it will be 901 * skipped because of the if statement above checking 902 * for P_SYSTEM 903 */ 904 if ((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) != P_INMEM) 905 goto nextproc; 906 907 switch (p->p_state) { 908 default: 909 /* Don't swap out processes in any sort 910 * of 'special' state. */ 911 break; 912 913 case PRS_NORMAL: 914 /* 915 * do not swapout a realtime process 916 * Check all the thread groups.. 917 */ 918 FOREACH_THREAD_IN_PROC(p, td) { 919 thread_lock(td); 920 if (PRI_IS_REALTIME(td->td_pri_class)) { 921 thread_unlock(td); 922 goto nextproc; 923 } 924 slptime = (ticks - td->td_slptick) / hz; 925 /* 926 * Guarantee swap_idle_threshold1 927 * time in memory. 928 */ 929 if (slptime < swap_idle_threshold1) { 930 thread_unlock(td); 931 goto nextproc; 932 } 933 934 /* 935 * Do not swapout a process if it is 936 * waiting on a critical event of some 937 * kind or there is a thread whose 938 * pageable memory may be accessed. 939 * 940 * This could be refined to support 941 * swapping out a thread. 942 */ 943 if (!thread_safetoswapout(td)) { 944 thread_unlock(td); 945 goto nextproc; 946 } 947 /* 948 * If the system is under memory stress, 949 * or if we are swapping 950 * idle processes >= swap_idle_threshold2, 951 * then swap the process out. 952 */ 953 if (((action & VM_SWAP_NORMAL) == 0) && 954 (((action & VM_SWAP_IDLE) == 0) || 955 (slptime < swap_idle_threshold2))) { 956 thread_unlock(td); 957 goto nextproc; 958 } 959 960 if (minslptime > slptime) 961 minslptime = slptime; 962 thread_unlock(td); 963 } 964 965 /* 966 * If the pageout daemon didn't free enough pages, 967 * or if this process is idle and the system is 968 * configured to swap proactively, swap it out. 969 */ 970 if ((action & VM_SWAP_NORMAL) || 971 ((action & VM_SWAP_IDLE) && 972 (minslptime > swap_idle_threshold2))) { 973 if (swapout(p) == 0) 974 didswap++; 975 PROC_UNLOCK(p); 976 vm_map_unlock(&vm->vm_map); 977 vmspace_free(vm); 978 sx_sunlock(&allproc_lock); 979 goto retry; 980 } 981 } 982 nextproc: 983 PROC_UNLOCK(p); 984 vm_map_unlock(&vm->vm_map); 985 nextproc1: 986 vmspace_free(vm); 987 continue; 988 } 989 sx_sunlock(&allproc_lock); 990 /* 991 * If we swapped something out, and another process needed memory, 992 * then wakeup the sched process. 993 */ 994 if (didswap) 995 wakeup(&proc0); 996 } 997 998 static void 999 swapclear(p) 1000 struct proc *p; 1001 { 1002 struct thread *td; 1003 1004 PROC_LOCK_ASSERT(p, MA_OWNED); 1005 1006 FOREACH_THREAD_IN_PROC(p, td) { 1007 thread_lock(td); 1008 td->td_flags |= TDF_INMEM; 1009 td->td_flags &= ~TDF_SWAPINREQ; 1010 TD_CLR_SWAPPED(td); 1011 if (TD_CAN_RUN(td)) 1012 if (setrunnable(td)) { 1013 #ifdef INVARIANTS 1014 /* 1015 * XXX: We just cleared TDI_SWAPPED 1016 * above and set TDF_INMEM, so this 1017 * should never happen. 1018 */ 1019 panic("not waking up swapper"); 1020 #endif 1021 } 1022 thread_unlock(td); 1023 } 1024 p->p_flag &= ~(P_SWAPPINGIN|P_SWAPPINGOUT); 1025 p->p_flag |= P_INMEM; 1026 } 1027 1028 static int 1029 swapout(p) 1030 struct proc *p; 1031 { 1032 struct thread *td; 1033 1034 PROC_LOCK_ASSERT(p, MA_OWNED); 1035 #if defined(SWAP_DEBUG) 1036 printf("swapping out %d\n", p->p_pid); 1037 #endif 1038 1039 /* 1040 * The states of this process and its threads may have changed 1041 * by now. Assuming that there is only one pageout daemon thread, 1042 * this process should still be in memory. 1043 */ 1044 KASSERT((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) == P_INMEM, 1045 ("swapout: lost a swapout race?")); 1046 1047 /* 1048 * remember the process resident count 1049 */ 1050 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); 1051 /* 1052 * Check and mark all threads before we proceed. 1053 */ 1054 p->p_flag &= ~P_INMEM; 1055 p->p_flag |= P_SWAPPINGOUT; 1056 FOREACH_THREAD_IN_PROC(p, td) { 1057 thread_lock(td); 1058 if (!thread_safetoswapout(td)) { 1059 thread_unlock(td); 1060 swapclear(p); 1061 return (EBUSY); 1062 } 1063 td->td_flags &= ~TDF_INMEM; 1064 TD_SET_SWAPPED(td); 1065 thread_unlock(td); 1066 } 1067 td = FIRST_THREAD_IN_PROC(p); 1068 ++td->td_ru.ru_nswap; 1069 PROC_UNLOCK(p); 1070 1071 /* 1072 * This list is stable because all threads are now prevented from 1073 * running. The list is only modified in the context of a running 1074 * thread in this process. 1075 */ 1076 FOREACH_THREAD_IN_PROC(p, td) 1077 vm_thread_swapout(td); 1078 1079 PROC_LOCK(p); 1080 p->p_flag &= ~P_SWAPPINGOUT; 1081 p->p_swtick = ticks; 1082 return (0); 1083 } 1084 #endif /* !NO_SWAPPING */ 1085