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("$FreeBSD$"); 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 we want large import sizes. */ 128 #define KVA_QUANTUM_SHIFT (8 + 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 static vm_page_t 171 kmem_alloc_contig_pages(vm_object_t object, vm_pindex_t pindex, int domain, 172 int pflags, u_long npages, vm_paddr_t low, vm_paddr_t high, 173 u_long alignment, vm_paddr_t boundary, vm_memattr_t memattr) 174 { 175 vm_page_t m; 176 int tries; 177 bool wait; 178 179 VM_OBJECT_ASSERT_WLOCKED(object); 180 181 wait = (pflags & VM_ALLOC_WAITOK) != 0; 182 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 183 pflags |= VM_ALLOC_NOWAIT; 184 for (tries = wait ? 3 : 1;; tries--) { 185 m = vm_page_alloc_contig_domain(object, pindex, domain, pflags, 186 npages, low, high, alignment, boundary, memattr); 187 if (m != NULL || tries == 0) 188 break; 189 190 VM_OBJECT_WUNLOCK(object); 191 if (!vm_page_reclaim_contig_domain(domain, pflags, npages, 192 low, high, alignment, boundary) && wait) 193 vm_wait_domain(domain); 194 VM_OBJECT_WLOCK(object); 195 } 196 return (m); 197 } 198 199 /* 200 * Allocates a region from the kernel address map and physical pages 201 * within the specified address range to the kernel object. Creates a 202 * wired mapping from this region to these pages, and returns the 203 * region's starting virtual address. The allocated pages are not 204 * necessarily physically contiguous. If M_ZERO is specified through the 205 * given flags, then the pages are zeroed before they are mapped. 206 */ 207 static vm_offset_t 208 kmem_alloc_attr_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 209 vm_paddr_t high, vm_memattr_t memattr) 210 { 211 vmem_t *vmem; 212 vm_object_t object; 213 vm_offset_t addr, i, offset; 214 vm_page_t m; 215 int pflags; 216 vm_prot_t prot; 217 218 object = kernel_object; 219 size = round_page(size); 220 vmem = vm_dom[domain].vmd_kernel_arena; 221 if (vmem_alloc(vmem, size, M_BESTFIT | flags, &addr)) 222 return (0); 223 offset = addr - VM_MIN_KERNEL_ADDRESS; 224 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 225 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 226 VM_OBJECT_WLOCK(object); 227 for (i = 0; i < size; i += PAGE_SIZE) { 228 m = kmem_alloc_contig_pages(object, atop(offset + i), 229 domain, pflags, 1, low, high, PAGE_SIZE, 0, memattr); 230 if (m == NULL) { 231 VM_OBJECT_WUNLOCK(object); 232 kmem_unback(object, addr, i); 233 vmem_free(vmem, addr, size); 234 return (0); 235 } 236 KASSERT(vm_phys_domain(m) == domain, 237 ("kmem_alloc_attr_domain: Domain mismatch %d != %d", 238 vm_phys_domain(m), domain)); 239 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 240 pmap_zero_page(m); 241 m->valid = VM_PAGE_BITS_ALL; 242 pmap_enter(kernel_pmap, addr + i, m, prot, 243 prot | PMAP_ENTER_WIRED, 0); 244 } 245 VM_OBJECT_WUNLOCK(object); 246 return (addr); 247 } 248 249 vm_offset_t 250 kmem_alloc_attr(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 251 vm_memattr_t memattr) 252 { 253 254 return (kmem_alloc_attr_domainset(DOMAINSET_RR(), size, flags, low, 255 high, memattr)); 256 } 257 258 vm_offset_t 259 kmem_alloc_attr_domainset(struct domainset *ds, vm_size_t size, int flags, 260 vm_paddr_t low, vm_paddr_t high, vm_memattr_t memattr) 261 { 262 struct vm_domainset_iter di; 263 vm_offset_t addr; 264 int domain; 265 266 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 267 do { 268 addr = kmem_alloc_attr_domain(domain, size, flags, low, high, 269 memattr); 270 if (addr != 0) 271 break; 272 } while (vm_domainset_iter_policy(&di, &domain) == 0); 273 274 return (addr); 275 } 276 277 /* 278 * Allocates a region from the kernel address map and physically 279 * contiguous pages within the specified address range to the kernel 280 * object. Creates a wired mapping from this region to these pages, and 281 * returns the region's starting virtual address. If M_ZERO is specified 282 * through the given flags, then the pages are zeroed before they are 283 * mapped. 284 */ 285 static vm_offset_t 286 kmem_alloc_contig_domain(int domain, vm_size_t size, int flags, vm_paddr_t low, 287 vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 288 vm_memattr_t memattr) 289 { 290 vmem_t *vmem; 291 vm_object_t object; 292 vm_offset_t addr, offset, tmp; 293 vm_page_t end_m, m; 294 u_long npages; 295 int pflags; 296 297 object = kernel_object; 298 size = round_page(size); 299 vmem = vm_dom[domain].vmd_kernel_arena; 300 if (vmem_alloc(vmem, size, flags | M_BESTFIT, &addr)) 301 return (0); 302 offset = addr - VM_MIN_KERNEL_ADDRESS; 303 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 304 npages = atop(size); 305 VM_OBJECT_WLOCK(object); 306 m = kmem_alloc_contig_pages(object, atop(offset), domain, 307 pflags, npages, low, high, alignment, boundary, memattr); 308 if (m == NULL) { 309 VM_OBJECT_WUNLOCK(object); 310 vmem_free(vmem, addr, size); 311 return (0); 312 } 313 KASSERT(vm_phys_domain(m) == domain, 314 ("kmem_alloc_contig_domain: Domain mismatch %d != %d", 315 vm_phys_domain(m), domain)); 316 end_m = m + npages; 317 tmp = addr; 318 for (; m < end_m; m++) { 319 if ((flags & M_ZERO) && (m->flags & PG_ZERO) == 0) 320 pmap_zero_page(m); 321 m->valid = VM_PAGE_BITS_ALL; 322 pmap_enter(kernel_pmap, tmp, m, VM_PROT_RW, 323 VM_PROT_RW | PMAP_ENTER_WIRED, 0); 324 tmp += PAGE_SIZE; 325 } 326 VM_OBJECT_WUNLOCK(object); 327 return (addr); 328 } 329 330 vm_offset_t 331 kmem_alloc_contig(vm_size_t size, int flags, vm_paddr_t low, vm_paddr_t high, 332 u_long alignment, vm_paddr_t boundary, vm_memattr_t memattr) 333 { 334 335 return (kmem_alloc_contig_domainset(DOMAINSET_RR(), size, flags, low, 336 high, alignment, boundary, memattr)); 337 } 338 339 vm_offset_t 340 kmem_alloc_contig_domainset(struct domainset *ds, vm_size_t size, int flags, 341 vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary, 342 vm_memattr_t memattr) 343 { 344 struct vm_domainset_iter di; 345 vm_offset_t addr; 346 int domain; 347 348 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 349 do { 350 addr = kmem_alloc_contig_domain(domain, size, flags, low, high, 351 alignment, boundary, memattr); 352 if (addr != 0) 353 break; 354 } while (vm_domainset_iter_policy(&di, &domain) == 0); 355 356 return (addr); 357 } 358 359 /* 360 * kmem_suballoc: 361 * 362 * Allocates a map to manage a subrange 363 * of the kernel virtual address space. 364 * 365 * Arguments are as follows: 366 * 367 * parent Map to take range from 368 * min, max Returned endpoints of map 369 * size Size of range to find 370 * superpage_align Request that min is superpage aligned 371 */ 372 vm_map_t 373 kmem_suballoc(vm_map_t parent, vm_offset_t *min, vm_offset_t *max, 374 vm_size_t size, boolean_t superpage_align) 375 { 376 int ret; 377 vm_map_t result; 378 379 size = round_page(size); 380 381 *min = vm_map_min(parent); 382 ret = vm_map_find(parent, NULL, 0, min, size, 0, superpage_align ? 383 VMFS_SUPER_SPACE : VMFS_ANY_SPACE, VM_PROT_ALL, VM_PROT_ALL, 384 MAP_ACC_NO_CHARGE); 385 if (ret != KERN_SUCCESS) 386 panic("kmem_suballoc: bad status return of %d", ret); 387 *max = *min + size; 388 result = vm_map_create(vm_map_pmap(parent), *min, *max); 389 if (result == NULL) 390 panic("kmem_suballoc: cannot create submap"); 391 if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS) 392 panic("kmem_suballoc: unable to change range to submap"); 393 return (result); 394 } 395 396 /* 397 * kmem_malloc_domain: 398 * 399 * Allocate wired-down pages in the kernel's address space. 400 */ 401 static vm_offset_t 402 kmem_malloc_domain(int domain, vm_size_t size, int flags) 403 { 404 vmem_t *arena; 405 vm_offset_t addr; 406 int rv; 407 408 if (__predict_true((flags & M_EXEC) == 0)) 409 arena = vm_dom[domain].vmd_kernel_arena; 410 else 411 arena = vm_dom[domain].vmd_kernel_rwx_arena; 412 size = round_page(size); 413 if (vmem_alloc(arena, size, flags | M_BESTFIT, &addr)) 414 return (0); 415 416 rv = kmem_back_domain(domain, kernel_object, addr, size, flags); 417 if (rv != KERN_SUCCESS) { 418 vmem_free(arena, addr, size); 419 return (0); 420 } 421 return (addr); 422 } 423 424 vm_offset_t 425 kmem_malloc(vm_size_t size, int flags) 426 { 427 428 return (kmem_malloc_domainset(DOMAINSET_RR(), size, flags)); 429 } 430 431 vm_offset_t 432 kmem_malloc_domainset(struct domainset *ds, vm_size_t size, int flags) 433 { 434 struct vm_domainset_iter di; 435 vm_offset_t addr; 436 int domain; 437 438 vm_domainset_iter_policy_init(&di, ds, &domain, &flags); 439 do { 440 addr = kmem_malloc_domain(domain, size, flags); 441 if (addr != 0) 442 break; 443 } while (vm_domainset_iter_policy(&di, &domain) == 0); 444 445 return (addr); 446 } 447 448 /* 449 * kmem_back_domain: 450 * 451 * Allocate physical pages from the specified domain for the specified 452 * virtual address range. 453 */ 454 int 455 kmem_back_domain(int domain, vm_object_t object, vm_offset_t addr, 456 vm_size_t size, int flags) 457 { 458 vm_offset_t offset, i; 459 vm_page_t m, mpred; 460 vm_prot_t prot; 461 int pflags; 462 463 KASSERT(object == kernel_object, 464 ("kmem_back_domain: only supports kernel object.")); 465 466 offset = addr - VM_MIN_KERNEL_ADDRESS; 467 pflags = malloc2vm_flags(flags) | VM_ALLOC_NOBUSY | VM_ALLOC_WIRED; 468 pflags &= ~(VM_ALLOC_NOWAIT | VM_ALLOC_WAITOK | VM_ALLOC_WAITFAIL); 469 if (flags & M_WAITOK) 470 pflags |= VM_ALLOC_WAITFAIL; 471 prot = (flags & M_EXEC) != 0 ? VM_PROT_ALL : VM_PROT_RW; 472 473 i = 0; 474 VM_OBJECT_WLOCK(object); 475 retry: 476 mpred = vm_radix_lookup_le(&object->rtree, atop(offset + i)); 477 for (; i < size; i += PAGE_SIZE, mpred = m) { 478 m = vm_page_alloc_domain_after(object, atop(offset + i), 479 domain, pflags, mpred); 480 481 /* 482 * Ran out of space, free everything up and return. Don't need 483 * to lock page queues here as we know that the pages we got 484 * aren't on any queues. 485 */ 486 if (m == NULL) { 487 if ((flags & M_NOWAIT) == 0) 488 goto retry; 489 VM_OBJECT_WUNLOCK(object); 490 kmem_unback(object, addr, i); 491 return (KERN_NO_SPACE); 492 } 493 KASSERT(vm_phys_domain(m) == domain, 494 ("kmem_back_domain: Domain mismatch %d != %d", 495 vm_phys_domain(m), domain)); 496 if (flags & M_ZERO && (m->flags & PG_ZERO) == 0) 497 pmap_zero_page(m); 498 KASSERT((m->oflags & VPO_UNMANAGED) != 0, 499 ("kmem_malloc: page %p is managed", m)); 500 m->valid = VM_PAGE_BITS_ALL; 501 pmap_enter(kernel_pmap, addr + i, m, prot, 502 prot | PMAP_ENTER_WIRED, 0); 503 if (__predict_false((prot & VM_PROT_EXECUTE) != 0)) 504 m->oflags |= VPO_KMEM_EXEC; 505 } 506 VM_OBJECT_WUNLOCK(object); 507 508 return (KERN_SUCCESS); 509 } 510 511 /* 512 * kmem_back: 513 * 514 * Allocate physical pages for the specified virtual address range. 515 */ 516 int 517 kmem_back(vm_object_t object, vm_offset_t addr, vm_size_t size, int flags) 518 { 519 vm_offset_t end, next, start; 520 int domain, rv; 521 522 KASSERT(object == kernel_object, 523 ("kmem_back: only supports kernel object.")); 524 525 for (start = addr, end = addr + size; addr < end; addr = next) { 526 /* 527 * We must ensure that pages backing a given large virtual page 528 * all come from the same physical domain. 529 */ 530 if (vm_ndomains > 1) { 531 domain = (addr >> KVA_QUANTUM_SHIFT) % vm_ndomains; 532 while (VM_DOMAIN_EMPTY(domain)) 533 domain++; 534 next = roundup2(addr + 1, KVA_QUANTUM); 535 if (next > end || next < start) 536 next = end; 537 } else { 538 domain = 0; 539 next = end; 540 } 541 rv = kmem_back_domain(domain, object, addr, next - addr, flags); 542 if (rv != KERN_SUCCESS) { 543 kmem_unback(object, start, addr - start); 544 break; 545 } 546 } 547 return (rv); 548 } 549 550 /* 551 * kmem_unback: 552 * 553 * Unmap and free the physical pages underlying the specified virtual 554 * address range. 555 * 556 * A physical page must exist within the specified object at each index 557 * that is being unmapped. 558 */ 559 static struct vmem * 560 _kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 561 { 562 struct vmem *arena; 563 vm_page_t m, next; 564 vm_offset_t end, offset; 565 int domain; 566 567 KASSERT(object == kernel_object, 568 ("kmem_unback: only supports kernel object.")); 569 570 if (size == 0) 571 return (NULL); 572 pmap_remove(kernel_pmap, addr, addr + size); 573 offset = addr - VM_MIN_KERNEL_ADDRESS; 574 end = offset + size; 575 VM_OBJECT_WLOCK(object); 576 m = vm_page_lookup(object, atop(offset)); 577 domain = vm_phys_domain(m); 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 for (; offset < end; offset += PAGE_SIZE, m = next) { 583 next = vm_page_next(m); 584 vm_page_unwire_noq(m); 585 vm_page_free(m); 586 } 587 VM_OBJECT_WUNLOCK(object); 588 589 return (arena); 590 } 591 592 void 593 kmem_unback(vm_object_t object, vm_offset_t addr, vm_size_t size) 594 { 595 596 (void)_kmem_unback(object, addr, size); 597 } 598 599 /* 600 * kmem_free: 601 * 602 * Free memory allocated with kmem_malloc. The size must match the 603 * original allocation. 604 */ 605 void 606 kmem_free(vm_offset_t addr, vm_size_t size) 607 { 608 struct vmem *arena; 609 610 size = round_page(size); 611 arena = _kmem_unback(kernel_object, addr, size); 612 if (arena != NULL) 613 vmem_free(arena, addr, size); 614 } 615 616 /* 617 * kmap_alloc_wait: 618 * 619 * Allocates pageable memory from a sub-map of the kernel. If the submap 620 * has no room, the caller sleeps waiting for more memory in the submap. 621 * 622 * This routine may block. 623 */ 624 vm_offset_t 625 kmap_alloc_wait(vm_map_t map, vm_size_t size) 626 { 627 vm_offset_t addr; 628 629 size = round_page(size); 630 if (!swap_reserve(size)) 631 return (0); 632 633 for (;;) { 634 /* 635 * To make this work for more than one map, use the map's lock 636 * to lock out sleepers/wakers. 637 */ 638 vm_map_lock(map); 639 addr = vm_map_findspace(map, vm_map_min(map), size); 640 if (addr + size <= vm_map_max(map)) 641 break; 642 /* no space now; see if we can ever get space */ 643 if (vm_map_max(map) - vm_map_min(map) < size) { 644 vm_map_unlock(map); 645 swap_release(size); 646 return (0); 647 } 648 map->needs_wakeup = TRUE; 649 vm_map_unlock_and_wait(map, 0); 650 } 651 vm_map_insert(map, NULL, 0, addr, addr + size, VM_PROT_RW, VM_PROT_RW, 652 MAP_ACC_CHARGED); 653 vm_map_unlock(map); 654 return (addr); 655 } 656 657 /* 658 * kmap_free_wakeup: 659 * 660 * Returns memory to a submap of the kernel, and wakes up any processes 661 * waiting for memory in that map. 662 */ 663 void 664 kmap_free_wakeup(vm_map_t map, vm_offset_t addr, vm_size_t size) 665 { 666 667 vm_map_lock(map); 668 (void) vm_map_delete(map, trunc_page(addr), round_page(addr + size)); 669 if (map->needs_wakeup) { 670 map->needs_wakeup = FALSE; 671 vm_map_wakeup(map); 672 } 673 vm_map_unlock(map); 674 } 675 676 void 677 kmem_init_zero_region(void) 678 { 679 vm_offset_t addr, i; 680 vm_page_t m; 681 682 /* 683 * Map a single physical page of zeros to a larger virtual range. 684 * This requires less looping in places that want large amounts of 685 * zeros, while not using much more physical resources. 686 */ 687 addr = kva_alloc(ZERO_REGION_SIZE); 688 m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | 689 VM_ALLOC_NOOBJ | VM_ALLOC_WIRED | VM_ALLOC_ZERO); 690 if ((m->flags & PG_ZERO) == 0) 691 pmap_zero_page(m); 692 for (i = 0; i < ZERO_REGION_SIZE; i += PAGE_SIZE) 693 pmap_qenter(addr + i, &m, 1); 694 pmap_protect(kernel_pmap, addr, addr + ZERO_REGION_SIZE, VM_PROT_READ); 695 696 zero_region = (const void *)addr; 697 } 698 699 /* 700 * Import KVA from the kernel map into the kernel arena. 701 */ 702 static int 703 kva_import(void *unused, vmem_size_t size, int flags, vmem_addr_t *addrp) 704 { 705 vm_offset_t addr; 706 int result; 707 708 KASSERT((size % KVA_QUANTUM) == 0, 709 ("kva_import: Size %jd is not a multiple of %d", 710 (intmax_t)size, (int)KVA_QUANTUM)); 711 addr = vm_map_min(kernel_map); 712 result = vm_map_find(kernel_map, NULL, 0, &addr, size, 0, 713 VMFS_SUPER_SPACE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 714 if (result != KERN_SUCCESS) 715 return (ENOMEM); 716 717 *addrp = addr; 718 719 return (0); 720 } 721 722 /* 723 * Import KVA from a parent arena into a per-domain arena. Imports must be 724 * KVA_QUANTUM-aligned and a multiple of KVA_QUANTUM in size. 725 */ 726 static int 727 kva_import_domain(void *arena, vmem_size_t size, int flags, vmem_addr_t *addrp) 728 { 729 730 KASSERT((size % KVA_QUANTUM) == 0, 731 ("kva_import_domain: Size %jd is not a multiple of %d", 732 (intmax_t)size, (int)KVA_QUANTUM)); 733 return (vmem_xalloc(arena, size, KVA_QUANTUM, 0, 0, VMEM_ADDR_MIN, 734 VMEM_ADDR_MAX, flags, addrp)); 735 } 736 737 /* 738 * kmem_init: 739 * 740 * Create the kernel map; insert a mapping covering kernel text, 741 * data, bss, and all space allocated thus far (`boostrap' data). The 742 * new map will thus map the range between VM_MIN_KERNEL_ADDRESS and 743 * `start' as allocated, and the range between `start' and `end' as free. 744 * Create the kernel vmem arena and its per-domain children. 745 */ 746 void 747 kmem_init(vm_offset_t start, vm_offset_t end) 748 { 749 vm_map_t m; 750 int domain; 751 752 m = vm_map_create(kernel_pmap, VM_MIN_KERNEL_ADDRESS, end); 753 m->system_map = 1; 754 vm_map_lock(m); 755 /* N.B.: cannot use kgdb to debug, starting with this assignment ... */ 756 kernel_map = m; 757 (void) vm_map_insert(m, NULL, (vm_ooffset_t) 0, 758 #ifdef __amd64__ 759 KERNBASE, 760 #else 761 VM_MIN_KERNEL_ADDRESS, 762 #endif 763 start, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT); 764 /* ... and ending with the completion of the above `insert' */ 765 vm_map_unlock(m); 766 767 /* 768 * Initialize the kernel_arena. This can grow on demand. 769 */ 770 vmem_init(kernel_arena, "kernel arena", 0, 0, PAGE_SIZE, 0, 0); 771 vmem_set_import(kernel_arena, kva_import, NULL, NULL, KVA_QUANTUM); 772 773 for (domain = 0; domain < vm_ndomains; domain++) { 774 /* 775 * Initialize the per-domain arenas. These are used to color 776 * the KVA space in a way that ensures that virtual large pages 777 * are backed by memory from the same physical domain, 778 * maximizing the potential for superpage promotion. 779 */ 780 vm_dom[domain].vmd_kernel_arena = vmem_create( 781 "kernel arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 782 vmem_set_import(vm_dom[domain].vmd_kernel_arena, 783 kva_import_domain, NULL, kernel_arena, KVA_QUANTUM); 784 785 /* 786 * In architectures with superpages, maintain separate arenas 787 * for allocations with permissions that differ from the 788 * "standard" read/write permissions used for kernel memory, 789 * so as not to inhibit superpage promotion. 790 */ 791 #if VM_NRESERVLEVEL > 0 792 vm_dom[domain].vmd_kernel_rwx_arena = vmem_create( 793 "kernel rwx arena domain", 0, 0, PAGE_SIZE, 0, M_WAITOK); 794 vmem_set_import(vm_dom[domain].vmd_kernel_rwx_arena, 795 kva_import_domain, (vmem_release_t *)vmem_xfree, 796 kernel_arena, KVA_QUANTUM); 797 #else 798 vm_dom[domain].vmd_kernel_rwx_arena = 799 vm_dom[domain].vmd_kernel_arena; 800 #endif 801 } 802 } 803 804 /* 805 * kmem_bootstrap_free: 806 * 807 * Free pages backing preloaded data (e.g., kernel modules) to the 808 * system. Currently only supported on platforms that create a 809 * vm_phys segment for preloaded data. 810 */ 811 void 812 kmem_bootstrap_free(vm_offset_t start, vm_size_t size) 813 { 814 #if defined(__i386__) || defined(__amd64__) 815 struct vm_domain *vmd; 816 vm_offset_t end, va; 817 vm_paddr_t pa; 818 vm_page_t m; 819 820 end = trunc_page(start + size); 821 start = round_page(start); 822 823 for (va = start; va < end; va += PAGE_SIZE) { 824 pa = pmap_kextract(va); 825 m = PHYS_TO_VM_PAGE(pa); 826 827 vmd = vm_pagequeue_domain(m); 828 vm_domain_free_lock(vmd); 829 vm_phys_free_pages(m, 0); 830 vm_domain_free_unlock(vmd); 831 832 vm_domain_freecnt_inc(vmd, 1); 833 vm_cnt.v_page_count++; 834 } 835 pmap_remove(kernel_pmap, start, end); 836 (void)vmem_add(kernel_arena, start, end - start, M_WAITOK); 837 #endif 838 } 839 840 /* 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 != 0) 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, 861 CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, 0, 0, debug_vm_lowmem, "I", 862 "set to trigger vm_lowmem event with given flags"); 863 864 static int 865 debug_uma_reclaim(SYSCTL_HANDLER_ARGS) 866 { 867 int error, i; 868 869 i = 0; 870 error = sysctl_handle_int(oidp, &i, 0, req); 871 if (error != 0) 872 return (error); 873 if (i != 0) 874 uma_reclaim(); 875 return (0); 876 } 877 878 SYSCTL_PROC(_debug, OID_AUTO, uma_reclaim, 879 CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RW, 0, 0, debug_uma_reclaim, "I", 880 "set to generate request to reclaim uma caches");
Cache object: 0e6760af7cbfa6aa0da08f3c3e58aed7
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