Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_kern.c
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1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * from: @(#)vm_kern.c 8.3 (Berkeley) 1/12/94 35 * 36 * 37 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 38 * All rights reserved. 39 * 40 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 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 /* 64 * Kernel memory management. 65 */ 66 67 #include <sys/cdefs.h> 68 __FBSDID("$FreeBSD: releng/12.0/sys/vm/vm_kern.c 340401 2018-11-13 18:21:47Z markj $"); 69 70 #include "opt_vm.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/kernel.h> /* for ticks and hz */ 75 #include <sys/domainset.h> 76 #include <sys/eventhandler.h> 77 #include <sys/lock.h> 78 #include <sys/proc.h> 79 #include <sys/malloc.h> 80 #include <sys/rwlock.h> 81 #include <sys/sysctl.h> 82 #include <sys/vmem.h> 83 #include <sys/vmmeter.h> 84 85 #include <vm/vm.h> 86 #include <vm/vm_param.h> 87 #include <vm/vm_domainset.h> 88 #include <vm/vm_kern.h> 89 #include <vm/pmap.h> 90 #include <vm/vm_map.h> 91 #include <vm/vm_object.h> 92 #include <vm/vm_page.h> 93 #include <vm/vm_pageout.h> 94 #include <vm/vm_phys.h> 95 #include <vm/vm_pagequeue.h> 96 #include <vm/vm_radix.h> 97 #include <vm/vm_extern.h> 98 #include <vm/uma.h> 99 100 vm_map_t kernel_map; 101 vm_map_t exec_map; 102 vm_map_t pipe_map; 103 104 const void *zero_region; 105 CTASSERT((ZERO_REGION_SIZE & PAGE_MASK) == 0); 106 107 /* NB: Used by kernel debuggers. */ 108 const u_long vm_maxuser_address = VM_MAXUSER_ADDRESS; 109 110 u_int exec_map_entry_size; 111 u_int exec_map_entries; 112 113 SYSCTL_ULONG(_vm, OID_AUTO, min_kernel_address, CTLFLAG_RD, 114 SYSCTL_NULL_ULONG_PTR, VM_MIN_KERNEL_ADDRESS, "Min kernel address"); 115 116 SYSCTL_ULONG(_vm, OID_AUTO, max_kernel_address, CTLFLAG_RD, 117 #if defined(__arm__) || defined(__sparc64__) 118 &vm_max_kernel_address, 0, 119 #else 120 SYSCTL_NULL_ULONG_PTR, VM_MAX_KERNEL_ADDRESS, 121 #endif 122 "Max kernel address"); 123 124 #if VM_NRESERVLEVEL > 0 125 #define KVA_QUANTUM_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) 126 #else 127 /* On non-superpage architectures want large import sizes. */ 128 #define KVA_QUANTUM_SHIFT (10 + PAGE_SHIFT) 129 #endif 130 #define KVA_QUANTUM (1 << KVA_QUANTUM_SHIFT) 131 132 /* 133 * kva_alloc: 134 * 135 * Allocate a virtual address range with no underlying object and 136 * no initial mapping to physical memory. Any mapping from this 137 * range to physical memory must be explicitly created prior to 138 * its use, typically with pmap_qenter(). Any attempt to create 139 * a mapping on demand through vm_fault() will result in a panic. 140 */ 141 vm_offset_t 142 kva_alloc(vm_size_t size) 143 { 144 vm_offset_t addr; 145 146 size = round_page(size); 147 if (vmem_alloc(kernel_arena, size, M_BESTFIT | M_NOWAIT, &addr)) 148 return (0); 149 150 return (addr); 151 } 152 153 /* 154 * kva_free: 155 * 156 * Release a region of kernel virtual memory allocated 157 * with kva_alloc, and return the physical pages 158 * associated with that region. 159 * 160 * This routine may not block on kernel maps. 161 */ 162 void 163 kva_free(vm_offset_t addr, vm_size_t size) 164 { 165 166 size = round_page(size); 167 vmem_free(kernel_arena, addr, size); 168 } 169 170 /* 171 * Allocates a region from the kernel address map and physical pages 172 * within the specified address range to the kernel object. Creates a 173 * wired mapping from this region to these pages, and returns the 174 * region's starting virtual address. The allocated pages are not 175 * necessarily physically contiguous. If M_ZERO is specified through the 176 * given flags, then the pages are zeroed before they are mapped. 177 */ 178 static vm_offset_t 179 kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 180 vm_paddr_t high, vm_memattr_t memattr) 181 { 182 vmem_t *vmem; 183 vm_object_t object = kernel_object; 184 vm_offset_t addr, i, offset; 185 vm_page_t m; 186 int pflags, tries; 187 188 size = round_page(size); 189 vmem = vm_dom[domain].vmd_kernel_arena; 190 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 191 return (0); 192 offset = addr - VM_MIN_KERNEL_ADDRESS; 193 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 194 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 195 pflags |= VM_ALLOC_NOWAIT; 196 VM_OBJECT_WLOCK(object); 197 for (i = 0; i < size; i += PAGE_SIZE) { 198 tries = 0; 199 retry: 200 m = vm_page_alloc_contig_domain(object, atop(offset + i), 201 domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr); 202 if (m == NULL) { 203 VM_OBJECT_WUNLOCK(object); 204 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 205 if (!vm_page_reclaim_contig_domain(domain, 206 pflags, 1, low, high, PAGE_SIZE, 0) && 207 (flags & M_WAITOK) != 0) 208 vm_wait_domain(domain); 209 VM_OBJECT_WLOCK(object); 210 tries++; 211 goto retry; 212 } 213 kmem_unback(object, addr, i); 214 vmem_free(vmem, addr, size); 215 return (0); 216 } 217 KASSERT(vm_phys_domain(m) == domain, 218 ("kmem_alloc_attr_domain: Domain mismatch %d != %d", 219 vm_phys_domain(m), domain)); 220 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 221 pmap_zero_page(m); 222 m->valid = VM_PAGE_BITS_ALL; 223 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_RW, 224 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 225 } 226 VM_OBJECT_WUNLOCK(object); 227 return (addr); 228 } 229 230 vm_offset_t 231 kmem_alloc_attr(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 232 vm_memattr_t memattr) 233 { 234 235 return (kmem_alloc_attr_domainset(DOMAINSET_RR(), size, flags, low, 236 high, memattr)); 237 } 238 239 vm_offset_t 240 kmem_alloc_attr_domainset(struct domainset *ds, vm_size_t size, int flags, 241 vm_paddr_t low, vm_paddr_t high, vm_memattr_t memattr) 242 { 243 struct vm_domainset_iter di; 244 vm_offset_t addr; 245 int domain; 246 247 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 248 do { 249 addr = kmem_alloc_attr_domain(domain, size, flags, low, high, 250 memattr); 251 if (addr != 0) 252 break; 253 } while (vm_domainset_iter_policy(&di, &domain) == 0); 254 255 return (addr); 256 } 257 258 /* 259 * Allocates a region from the kernel address map and physically 260 * contiguous pages within the specified address range to the kernel 261 * object. Creates a wired mapping from this region to these pages, and 262 * returns the region's starting virtual address. If M_ZERO is specified 263 * through the given flags, then the pages are zeroed before they are 264 * mapped. 265 */ 266 static vm_offset_t 267 kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 268 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 269 vm_memattr_t memattr) 270 { 271 vmem_t *vmem; 272 vm_object_t object = kernel_object; 273 vm_offset_t addr, offset, tmp; 274 vm_page_t end_m, m; 275 u_long npages; 276 int pflags, tries; 277 278 size = round_page(size); 279 vmem = vm_dom[domain].vmd_kernel_arena; 280 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 281 return (0); 282 offset = addr - VM_MIN_KERNEL_ADDRESS; 283 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 284 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 285 pflags |= VM_ALLOC_NOWAIT; 286 npages = atop(size); 287 VM_OBJECT_WLOCK(object); 288 tries = 0; 289 retry: 290 m = vm_page_alloc_contig_domain(object, atop(offset), domain, pflags, 291 npages, low, high, alignment, boundary, memattr); 292 if (m == NULL) { 293 VM_OBJECT_WUNLOCK(object); 294 if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) { 295 if (!vm_page_reclaim_contig_domain(domain, pflags, 296 npages, low, high, alignment, boundary) && 297 (flags & M_WAITOK) != 0) 298 vm_wait_domain(domain); 299 VM_OBJECT_WLOCK(object); 300 tries++; 301 goto retry; 302 } 303 vmem_free(vmem, addr, size); 304 return (0); 305 } 306 KASSERT(vm_phys_domain(m) == domain, 307 ("kmem_alloc_contig_domain: Domain mismatch %d != %d", 308 vm_phys_domain(m), domain)); 309 end_m = m + npages; 310 tmp = addr; 311 for (; m < end_m; m++) { 312 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 313 pmap_zero_page(m); 314 m->valid = VM_PAGE_BITS_ALL; 315 pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW, 316 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 317 tmp += PAGE_SIZE; 318 } 319 VM_OBJECT_WUNLOCK(object); 320 return (addr); 321 } 322 323 vm_offset_t 324 kmem_alloc_contig(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 325 u_long alignment, vm_paddr_t boundary, vm_memattr_t memattr) 326 { 327 328 return (kmem_alloc_contig_domainset(DOMAINSET_RR(), size, flags, low, 329 high, alignment, boundary, memattr)); 330 } 331 332 vm_offset_t 333 kmem_alloc_contig_domainset(struct domainset *ds, vm_size_t size, int flags, 334 vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 335 vm_memattr_t memattr) 336 { 337 struct vm_domainset_iter di; 338 vm_offset_t addr; 339 int domain; 340 341 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 342 do { 343 addr = kmem_alloc_contig_domain(domain, size, flags, low, high, 344 alignment, boundary, memattr); 345 if (addr != 0) 346 break; 347 } while (vm_domainset_iter_policy(&di, &domain) == 0); 348 349 return (addr); 350 } 351 352 /* 353 * kmem_suballoc: 354 * 355 * Allocates a map to manage a subrange 356 * of the kernel virtual address space. 357 * 358 * Arguments are as follows: 359 * 360 * parent Map to take range from 361 * min, max Returned endpoints of map 362 * size Size of range to find 363 * superpage_align Request that min is superpage aligned 364 */ 365 vm_map_t 366 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 367 vm_size_t size, boolean_t superpage_align) 368 { 369 int ret; 370 vm_map_t result; 371 372 size = round_page(size); 373 374 *min = vm_map_min(parent); 375 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 376 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 377 MAP_ACC_NO_CHARGE); 378 if (ret != KERN_SUCCESS) 379 panic("kmem_suballoc: bad status return of %d", ret); 380 *max = *min + size; 381 result = vm_map_create(vm_map_pmap(parent), *min, *max); 382 if (result == NULL) 383 panic("kmem_suballoc: cannot create submap"); 384 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 385 panic("kmem_suballoc: unable to change range to submap"); 386 return (result); 387 } 388 389 /* 390 * kmem_malloc_domain: 391 * 392 * Allocate wired-down pages in the kernel's address space. 393 */ 394 static vm_offset_t 395 kmem_malloc_domain(int domain, vm_size_t size, int flags) 396 { 397 vmem_t *arena; 398 vm_offset_t addr; 399 int rv; 400 401 #if VM_NRESERVLEVEL > 0 402 if (__predict_true((flags & M_EXEC) == 0)) 403 arena = vm_dom[domain].vmd_kernel_arena; 404 else 405 arena = vm_dom[domain].vmd_kernel_rwx_arena; 406 #else 407 arena = vm_dom[domain].vmd_kernel_arena; 408 #endif 409 size = round_page(size); 410 if (vmem_alloc(arena, size, flags | M_BESTFIT, &addr)) 411 return (0); 412 413 rv = kmem_back_domain(domain, kernel_object, addr, size, flags); 414 if (rv != KERN_SUCCESS) { 415 vmem_free(arena, addr, size); 416 return (0); 417 } 418 return (addr); 419 } 420 421 vm_offset_t 422 kmem_malloc(vm_size_t size, int flags) 423 { 424 425 return (kmem_malloc_domainset(DOMAINSET_RR(), size, flags)); 426 } 427 428 vm_offset_t 429 kmem_malloc_domainset(struct domainset *ds, vm_size_t size, int flags) 430 { 431 struct vm_domainset_iter di; 432 vm_offset_t addr; 433 int domain; 434 435 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 436 do { 437 addr = kmem_malloc_domain(domain, size, flags); 438 if (addr != 0) 439 break; 440 } while (vm_domainset_iter_policy(&di, &domain) == 0); 441 442 return (addr); 443 } 444 445 /* 446 * kmem_back_domain: 447 * 448 * Allocate physical pages from the specified domain for the specified 449 * virtual address range. 450 */ 451 int 452 kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr, 453 vm_size_t size, int flags) 454 { 455 vm_offset_t offset, i; 456 vm_page_t m, mpred; 457 vm_prot_t prot; 458 int pflags; 459 460 KASSERT(object == kernel_object, 461 ("kmem_back_domain: only supports kernel object.")); 462 463 offset = addr - VM_MIN_KERNEL_ADDRESS; 464 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 465 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 466 if (flags & M_WAITOK) 467 pflags |= VM_ALLOC_WAITFAIL; 468 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 469 470 i = 0; 471 VM_OBJECT_WLOCK(object); 472 retry: 473 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 474 for (; i < size; i += PAGE_SIZE, mpred = m) { 475 m = vm_page_alloc_domain_after(object, atop(offset + i), 476 domain, pflags, mpred); 477 478 /* 479 * Ran out of space, free everything up and return. Don't need 480 * to lock page queues here as we know that the pages we got 481 * aren't on any queues. 482 */ 483 if (m == NULL) { 484 if ((flags & M_NOWAIT) == 0) 485 goto retry; 486 VM_OBJECT_WUNLOCK(object); 487 kmem_unback(object, addr, i); 488 return (KERN_NO_SPACE); 489 } 490 KASSERT(vm_phys_domain(m) == domain, 491 ("kmem_back_domain: Domain mismatch %d != %d", 492 vm_phys_domain(m), domain)); 493 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 494 pmap_zero_page(m); 495 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 496 ("kmem_malloc: page %p is managed", m)); 497 m->valid = VM_PAGE_BITS_ALL; 498 pmap_enter(kernel_pmap, addr + i, m, prot, 499 prot | PMAP_ENTER_WIRED, 0); 500 #if VM_NRESERVLEVEL > 0 501 if (__predict_false((prot & VM_PROT_EXECUTE) != 0)) 502 m->oflags |= VPO_KMEM_EXEC; 503 #endif 504 } 505 VM_OBJECT_WUNLOCK(object); 506 507 return (KERN_SUCCESS); 508 } 509 510 /* 511 * kmem_back: 512 * 513 * Allocate physical pages for the specified virtual address range. 514 */ 515 int 516 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 517 { 518 vm_offset_t end, next, start; 519 int domain, rv; 520 521 KASSERT(object == kernel_object, 522 ("kmem_back: only supports kernel object.")); 523 524 for (start = addr, end = addr + size; addr < end; addr = next) { 525 /* 526 * We must ensure that pages backing a given large virtual page 527 * all come from the same physical domain. 528 */ 529 if (vm_ndomains > 1) { 530 domain = (addr >> KVA_QUANTUM_SHIFT) % vm_ndomains; 531 while (VM_DOMAIN_EMPTY(domain)) 532 domain++; 533 next = roundup2(addr + 1, KVA_QUANTUM); 534 if (next > end || next < start) 535 next = end; 536 } else { 537 domain = 0; 538 next = end; 539 } 540 rv = kmem_back_domain(domain, object, addr, next - addr, flags); 541 if (rv != KERN_SUCCESS) { 542 kmem_unback(object, start, addr - start); 543 break; 544 } 545 } 546 return (rv); 547 } 548 549 /* 550 * kmem_unback: 551 * 552 * Unmap and free the physical pages underlying the specified virtual 553 * address range. 554 * 555 * A physical page must exist within the specified object at each index 556 * that is being unmapped. 557 */ 558 static struct vmem * 559 _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 560 { 561 struct vmem *arena; 562 vm_page_t m, next; 563 vm_offset_t end, offset; 564 int domain; 565 566 KASSERT(object == kernel_object, 567 ("kmem_unback: only supports kernel object.")); 568 569 if (size == 0) 570 return (NULL); 571 pmap_remove(kernel_pmap, addr, addr + size); 572 offset = addr - VM_MIN_KERNEL_ADDRESS; 573 end = offset + size; 574 VM_OBJECT_WLOCK(object); 575 m = vm_page_lookup(object, atop(offset)); 576 domain = vm_phys_domain(m); 577 #if VM_NRESERVLEVEL > 0 578 if (__predict_true((m->oflags & VPO_KMEM_EXEC) == 0)) 579 arena = vm_dom[domain].vmd_kernel_arena; 580 else 581 arena = vm_dom[domain].vmd_kernel_rwx_arena; 582 #else 583 arena = vm_dom[domain].vmd_kernel_arena; 584 #endif 585 for (; offset < end; offset += PAGE_SIZE, m = next) { 586 next = vm_page_next(m); 587 vm_page_unwire(m, PQ_NONE); 588 vm_page_free(m); 589 } 590 VM_OBJECT_WUNLOCK(object); 591 592 return (arena); 593 } 594 595 void 596 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 597 { 598 599 (void)_kmem_unback(object, addr, size); 600 } 601 602 /* 603 * kmem_free: 604 * 605 * Free memory allocated with kmem_malloc. The size must match the 606 * original allocation. 607 */ 608 void 609 kmem_free(vm_offset_t addr, vm_size_t size) 610 { 611 struct vmem *arena; 612 613 size = round_page(size); 614 arena = _kmem_unback(kernel_object, addr, size); 615 if (arena != NULL) 616 vmem_free(arena, addr, size); 617 } 618 619 /* 620 * kmap_alloc_wait: 621 * 622 * Allocates pageable memory from a sub-map of the kernel. If the submap 623 * has no room, the caller sleeps waiting for more memory in the submap. 624 * 625 * This routine may block. 626 */ 627 vm_offset_t 628 kmap_alloc_wait(vm_map_t map, vm_size_t size) 629 { 630 vm_offset_t addr; 631 632 size = round_page(size); 633 if (!swap_reserve(size)) 634 return (0); 635 636 for (;;) { 637 /* 638 * To make this work for more than one map, use the map's lock 639 * to lock out sleepers/wakers. 640 */ 641 vm_map_lock(map); 642 if (vm_map_findspace(map, vm_map_min(map), size, &addr) == 0) 643 break; 644 /* no space now; see if we can ever get space */ 645 if (vm_map_max(map) - vm_map_min(map) < size) { 646 vm_map_unlock(map); 647 swap_release(size); 648 return (0); 649 } 650 map->needs_wakeup = TRUE; 651 vm_map_unlock_and_wait(map, 0); 652 } 653 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_ALL, 654 VM_PROT_ALL, MAP_ACC_CHARGED); 655 vm_map_unlock(map); 656 return (addr); 657 } 658 659 /* 660 * kmap_free_wakeup: 661 * 662 * Returns memory to a submap of the kernel, and wakes up any processes 663 * waiting for memory in that map. 664 */ 665 void 666 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 667 { 668 669 vm_map_lock(map); 670 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 671 if (map->needs_wakeup) { 672 map->needs_wakeup = FALSE; 673 vm_map_wakeup(map); 674 } 675 vm_map_unlock(map); 676 } 677 678 void 679 kmem_init_zero_region(void) 680 { 681 vm_offset_t addr, i; 682 vm_page_t m; 683 684 /* 685 * Map a single physical page of zeros to a larger virtual range. 686 * This requires less looping in places that want large amounts of 687 * zeros, while not using much more physical resources. 688 */ 689 addr = kva_alloc(ZERO_REGION_SIZE); 690 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 691 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 692 if ((m->flags & PG_ZERO) == 0) 693 pmap_zero_page(m); 694 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 695 pmap_qenter(addr + i, &m, 1); 696 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 697 698 zero_region = (const void *)addr; 699 } 700 701 /* 702 * Import KVA from the kernel map into the kernel arena. 703 */ 704 static int 705 kva_import(void *unused, vmem_size_t size, int flags, vmem_addr_t *addrp) 706 { 707 vm_offset_t addr; 708 int result; 709 710 KASSERT((size % KVA_QUANTUM) == 0, 711 ("kva_import: Size %jd is not a multiple of %d", 712 (intmax_t)size, (int)KVA_QUANTUM)); 713 addr = vm_map_min(kernel_map); 714 result = vm_map_find(kernel_map, NULL, 0, &addr, size, 0, 715 VMFS_SUPER_SPACE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 716 if (result != KERN_SUCCESS) 717 return (ENOMEM); 718 719 *addrp = addr; 720 721 return (0); 722 } 723 724 /* 725 * Import KVA from a parent arena into a per-domain arena. Imports must be 726 * KVA_QUANTUM-aligned and a multiple of KVA_QUANTUM in size. 727 */ 728 static int 729 kva_import_domain(void *arena, vmem_size_t size, int flags, vmem_addr_t *addrp) 730 { 731 732 KASSERT((size % KVA_QUANTUM) == 0, 733 ("kva_import_domain: Size %jd is not a multiple of %d", 734 (intmax_t)size, (int)KVA_QUANTUM)); 735 return (vmem_xalloc(arena, size, KVA_QUANTUM, 0, 0, VMEM_ADDR_MIN, 736 VMEM_ADDR_MAX, flags, addrp)); 737 } 738 739 /* 740 * kmem_init: 741 * 742 * Create the kernel map; insert a mapping covering kernel text, 743 * data, bss, and all space allocated thus far (`boostrap' data). The 744 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 745 * `start' as allocated, and the range between `start' and `end' as free. 746 * Create the kernel vmem arena and its per-domain children. 747 */ 748 void 749 kmem_init(vm_offset_t start, vm_offset_t end) 750 { 751 vm_map_t m; 752 int domain; 753 754 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 755 m->system_map = 1; 756 vm_map_lock(m); 757 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 758 kernel_map = m; 759 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 760 #ifdef __amd64__ 761 KERNBASE, 762 #else 763 VM_MIN_KERNEL_ADDRESS, 764 #endif 765 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 766 /* ... and ending with the completion of the above `insert' */ 767 vm_map_unlock(m); 768 769 /* 770 * Initialize the kernel_arena. This can grow on demand. 771 */ 772 vmem_init(kernel_arena, "kernel arena", 0, 0, PAGE_SIZE, 0, 0); 773 vmem_set_import(kernel_arena, kva_import, NULL, NULL, KVA_QUANTUM); 774 775 for (domain = 0; domain < vm_ndomains; domain++) { 776 /* 777 * Initialize the per-domain arenas. These are used to color 778 * the KVA space in a way that ensures that virtual large pages 779 * are backed by memory from the same physical domain, 780 * maximizing the potential for superpage promotion. 781 */ 782 vm_dom[domain].vmd_kernel_arena = vmem_create( 783 "kernel arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 784 vmem_set_import(vm_dom[domain].vmd_kernel_arena, 785 kva_import_domain, NULL, kernel_arena, KVA_QUANTUM); 786 787 /* 788 * In architectures with superpages, maintain separate arenas 789 * for allocations with permissions that differ from the 790 * "standard" read/write permissions used for kernel memory, 791 * so as not to inhibit superpage promotion. 792 */ 793 #if VM_NRESERVLEVEL > 0 794 vm_dom[domain].vmd_kernel_rwx_arena = vmem_create( 795 "kernel rwx arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 796 vmem_set_import(vm_dom[domain].vmd_kernel_rwx_arena, 797 kva_import_domain, (vmem_release_t *)vmem_xfree, 798 kernel_arena, KVA_QUANTUM); 799 #endif 800 } 801 } 802 803 /* 804 * kmem_bootstrap_free: 805 * 806 * Free pages backing preloaded data (e.g., kernel modules) to the 807 * system. Currently only supported on platforms that create a 808 * vm_phys segment for preloaded data. 809 */ 810 void 811 kmem_bootstrap_free(vm_offset_t start, vm_size_t size) 812 { 813 #if defined(__i386__) || defined(__amd64__) 814 struct vm_domain *vmd; 815 vm_offset_t end, va; 816 vm_paddr_t pa; 817 vm_page_t m; 818 819 end = trunc_page(start + size); 820 start = round_page(start); 821 822 for (va = start; va < end; va += PAGE_SIZE) { 823 pa = pmap_kextract(va); 824 m = PHYS_TO_VM_PAGE(pa); 825 826 vmd = vm_pagequeue_domain(m); 827 vm_domain_free_lock(vmd); 828 vm_phys_free_pages(m, 0); 829 vm_domain_free_unlock(vmd); 830 831 vm_domain_freecnt_inc(vmd, 1); 832 vm_cnt.v_page_count++; 833 } 834 pmap_remove(kernel_pmap, start, end); 835 (void)vmem_add(kernel_arena, start, end - start, M_WAITOK); 836 #endif 837 } 838 839 #ifdef DIAGNOSTIC 840 /* 841 * Allow userspace to directly trigger the VM drain routine for testing 842 * purposes. 843 */ 844 static int 845 debug_vm_lowmem(SYSCTL_HANDLER_ARGS) 846 { 847 int error, i; 848 849 i = 0; 850 error = sysctl_handle_int(oidp, &i, 0, req); 851 if (error) 852 return (error); 853 if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0) 854 return (EINVAL); 855 if (i != 0) 856 EVENTHANDLER_INVOKE(vm_lowmem, i); 857 return (0); 858 } 859 860 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0, 861 debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags"); 862 #endif
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