1 /* 2 * KERN_SLABALLOC.C - Kernel SLAB memory allocator 3 * 4 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $DragonFly: src/sys/kern/kern_slaballoc.c,v 1.8 2003/10/02 22:29:15 dillon Exp $ 29 * 30 * This module implements a slab allocator drop-in replacement for the 31 * kernel malloc(). 32 * 33 * A slab allocator reserves a ZONE for each chunk size, then lays the 34 * chunks out in an array within the zone. Allocation and deallocation 35 * is nearly instantanious, and fragmentation/overhead losses are limited 36 * to a fixed worst-case amount. 37 * 38 * The downside of this slab implementation is in the chunk size 39 * multiplied by the number of zones. ~80 zones * 128K = 10MB of VM per cpu. 40 * In a kernel implementation all this memory will be physical so 41 * the zone size is adjusted downward on machines with less physical 42 * memory. The upside is that overhead is bounded... this is the *worst* 43 * case overhead. 44 * 45 * Slab management is done on a per-cpu basis and no locking or mutexes 46 * are required, only a critical section. When one cpu frees memory 47 * belonging to another cpu's slab manager an asynchronous IPI message 48 * will be queued to execute the operation. In addition, both the 49 * high level slab allocator and the low level zone allocator optimize 50 * M_ZERO requests, and the slab allocator does not have to pre initialize 51 * the linked list of chunks. 52 * 53 * XXX Balancing is needed between cpus. Balance will be handled through 54 * asynchronous IPIs primarily by reassigning the z_Cpu ownership of chunks. 55 * 56 * XXX If we have to allocate a new zone and M_USE_RESERVE is set, use of 57 * the new zone should be restricted to M_USE_RESERVE requests only. 58 * 59 * Alloc Size Chunking Number of zones 60 * 0-127 8 16 61 * 128-255 16 8 62 * 256-511 32 8 63 * 512-1023 64 8 64 * 1024-2047 128 8 65 * 2048-4095 256 8 66 * 4096-8191 512 8 67 * 8192-16383 1024 8 68 * 16384-32767 2048 8 69 * (if PAGE_SIZE is 4K the maximum zone allocation is 16383) 70 * 71 * Allocations >= ZoneLimit go directly to kmem. 72 * 73 * API REQUIREMENTS AND SIDE EFFECTS 74 * 75 * To operate as a drop-in replacement to the FreeBSD-4.x malloc() we 76 * have remained compatible with the following API requirements: 77 * 78 * + small power-of-2 sized allocations are power-of-2 aligned (kern_tty) 79 * + all power-of-2 sized allocations are power-of-2 aligned (twe) 80 * + malloc(0) is allowed and returns non-NULL (ahc driver) 81 * + ability to allocate arbitrarily large chunks of memory 82 */ 83 84 #include "opt_vm.h" 85 86 #if !defined(NO_SLAB_ALLOCATOR) 87 88 #if defined(USE_KMEM_MAP) 89 #error "If you define USE_KMEM_MAP you must also define NO_SLAB_ALLOCATOR" 90 #endif 91 92 #include <sys/param.h> 93 #include <sys/systm.h> 94 #include <sys/kernel.h> 95 #include <sys/slaballoc.h> 96 #include <sys/mbuf.h> 97 #include <sys/vmmeter.h> 98 #include <sys/lock.h> 99 #include <sys/thread.h> 100 #include <sys/globaldata.h> 101 102 #include <vm/vm.h> 103 #include <vm/vm_param.h> 104 #include <vm/vm_kern.h> 105 #include <vm/vm_extern.h> 106 #include <vm/vm_object.h> 107 #include <vm/pmap.h> 108 #include <vm/vm_map.h> 109 #include <vm/vm_page.h> 110 #include <vm/vm_pageout.h> 111 112 #include <machine/cpu.h> 113 114 #include <sys/thread2.h> 115 116 #define arysize(ary) (sizeof(ary)/sizeof((ary)[0])) 117 118 /* 119 * Fixed globals (not per-cpu) 120 */ 121 static int ZoneSize; 122 static int ZoneLimit; 123 static int ZonePageCount; 124 static int ZonePageLimit; 125 static int ZoneMask; 126 static struct malloc_type *kmemstatistics; 127 static struct kmemusage *kmemusage; 128 static int32_t weirdary[16]; 129 130 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags); 131 static void kmem_slab_free(void *ptr, vm_size_t bytes); 132 133 /* 134 * Misc constants. Note that allocations that are exact multiples of 135 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module. 136 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists. 137 */ 138 #define MIN_CHUNK_SIZE 8 /* in bytes */ 139 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1) 140 #define ZONE_RELS_THRESH 2 /* threshold number of zones */ 141 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK) 142 143 /* 144 * The WEIRD_ADDR is used as known text to copy into free objects to 145 * try to create deterministic failure cases if the data is accessed after 146 * free. 147 */ 148 #define WEIRD_ADDR 0xdeadc0de 149 #define MAX_COPY sizeof(weirdary) 150 #define ZERO_LENGTH_PTR ((void *)-8) 151 152 /* 153 * Misc global malloc buckets 154 */ 155 156 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches"); 157 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory"); 158 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers"); 159 160 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options"); 161 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery"); 162 163 /* 164 * Initialize the slab memory allocator. We have to choose a zone size based 165 * on available physical memory. We choose a zone side which is approximately 166 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of 167 * 128K. The zone size is limited to the bounds set in slaballoc.h 168 * (typically 32K min, 128K max). 169 */ 170 static void kmeminit(void *dummy); 171 172 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL) 173 174 static void 175 kmeminit(void *dummy) 176 { 177 vm_poff_t limsize; 178 int usesize; 179 int i; 180 vm_pindex_t npg; 181 182 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE; 183 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) 184 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS; 185 186 usesize = (int)(limsize / 1024); /* convert to KB */ 187 188 ZoneSize = ZALLOC_MIN_ZONE_SIZE; 189 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize) 190 ZoneSize <<= 1; 191 ZoneLimit = ZoneSize / 4; 192 if (ZoneLimit > ZALLOC_ZONE_LIMIT) 193 ZoneLimit = ZALLOC_ZONE_LIMIT; 194 ZoneMask = ZoneSize - 1; 195 ZonePageLimit = PAGE_SIZE * 4; 196 ZonePageCount = ZoneSize / PAGE_SIZE; 197 198 npg = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / PAGE_SIZE; 199 kmemusage = kmem_slab_alloc(npg * sizeof(struct kmemusage), PAGE_SIZE, M_ZERO); 200 201 for (i = 0; i < arysize(weirdary); ++i) 202 weirdary[i] = WEIRD_ADDR; 203 204 if (bootverbose) 205 printf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024); 206 } 207 208 /* 209 * Initialize a malloc type tracking structure. NOTE! counters and such 210 * need to be made per-cpu (maybe with a MAXCPU array). 211 */ 212 void 213 malloc_init(void *data) 214 { 215 struct malloc_type *type = data; 216 vm_poff_t limsize; 217 218 if (type->ks_magic != M_MAGIC) 219 panic("malloc type lacks magic"); 220 221 if (type->ks_limit != 0) 222 return; 223 224 if (vmstats.v_page_count == 0) 225 panic("malloc_init not allowed before vm init"); 226 227 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE; 228 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) 229 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS; 230 type->ks_limit = limsize / 10; 231 232 type->ks_next = kmemstatistics; 233 kmemstatistics = type; 234 } 235 236 void 237 malloc_uninit(void *data) 238 { 239 struct malloc_type *type = data; 240 struct malloc_type *t; 241 242 if (type->ks_magic != M_MAGIC) 243 panic("malloc type lacks magic"); 244 245 if (vmstats.v_page_count == 0) 246 panic("malloc_uninit not allowed before vm init"); 247 248 if (type->ks_limit == 0) 249 panic("malloc_uninit on uninitialized type"); 250 251 #ifdef INVARIANTS 252 if (type->ks_memuse != 0) { 253 printf("malloc_uninit: %ld bytes of '%s' still allocated\n", 254 type->ks_memuse, type->ks_shortdesc); 255 } 256 #endif 257 if (type == kmemstatistics) { 258 kmemstatistics = type->ks_next; 259 } else { 260 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) { 261 if (t->ks_next == type) { 262 t->ks_next = type->ks_next; 263 break; 264 } 265 } 266 } 267 type->ks_next = NULL; 268 type->ks_limit = 0; 269 } 270 271 /* 272 * Calculate the zone index for the allocation request size and set the 273 * allocation request size to that particular zone's chunk size. 274 */ 275 static __inline int 276 zoneindex(unsigned long *bytes) 277 { 278 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */ 279 if (n < 128) { 280 *bytes = n = (n + 7) & ~7; 281 return(n / 8 - 1); /* 8 byte chunks, 16 zones */ 282 } 283 if (n < 256) { 284 *bytes = n = (n + 15) & ~15; 285 return(n / 16 + 7); 286 } 287 if (n < 8192) { 288 if (n < 512) { 289 *bytes = n = (n + 31) & ~31; 290 return(n / 32 + 15); 291 } 292 if (n < 1024) { 293 *bytes = n = (n + 63) & ~63; 294 return(n / 64 + 23); 295 } 296 if (n < 2048) { 297 *bytes = n = (n + 127) & ~127; 298 return(n / 128 + 31); 299 } 300 if (n < 4096) { 301 *bytes = n = (n + 255) & ~255; 302 return(n / 256 + 39); 303 } 304 *bytes = n = (n + 511) & ~511; 305 return(n / 512 + 47); 306 } 307 #if ZALLOC_ZONE_LIMIT > 8192 308 if (n < 16384) { 309 *bytes = n = (n + 1023) & ~1023; 310 return(n / 1024 + 55); 311 } 312 #endif 313 #if ZALLOC_ZONE_LIMIT > 16384 314 if (n < 32768) { 315 *bytes = n = (n + 2047) & ~2047; 316 return(n / 2048 + 63); 317 } 318 #endif 319 panic("Unexpected byte count %d", n); 320 return(0); 321 } 322 323 /* 324 * malloc() (SLAB ALLOCATOR) 325 * 326 * Allocate memory via the slab allocator. If the request is too large, 327 * or if it page-aligned beyond a certain size, we fall back to the 328 * KMEM subsystem. A SLAB tracking descriptor must be specified, use 329 * &SlabMisc if you don't care. 330 * 331 * M_NOWAIT - return NULL instead of blocking. 332 * M_ZERO - zero the returned memory. 333 * M_USE_RESERVE - allocate out of the system reserve if necessary 334 */ 335 void * 336 malloc(unsigned long size, struct malloc_type *type, int flags) 337 { 338 SLZone *z; 339 SLChunk *chunk; 340 SLGlobalData *slgd; 341 int zi; 342 343 slgd = &mycpu->gd_slab; 344 345 /* 346 * XXX silly to have this in the critical path. 347 */ 348 if (type->ks_limit == 0) { 349 crit_enter(); 350 if (type->ks_limit == 0) 351 malloc_init(type); 352 crit_exit(); 353 } 354 ++type->ks_calls; 355 356 /* 357 * Handle the case where the limit is reached. Panic if can't return 358 * NULL. XXX the original malloc code looped, but this tended to 359 * simply deadlock the computer. 360 */ 361 while (type->ks_memuse >= type->ks_limit) { 362 if (flags & (M_NOWAIT|M_NULLOK)) 363 return(NULL); 364 panic("%s: malloc limit exceeded", type->ks_shortdesc); 365 } 366 367 /* 368 * Handle the degenerate size == 0 case. Yes, this does happen. 369 * Return a special pointer. This is to maintain compatibility with 370 * the original malloc implementation. Certain devices, such as the 371 * adaptec driver, not only allocate 0 bytes, they check for NULL and 372 * also realloc() later on. Joy. 373 */ 374 if (size == 0) 375 return(ZERO_LENGTH_PTR); 376 377 /* 378 * Handle hysteresis from prior frees here in malloc(). We cannot 379 * safely manipulate the kernel_map in free() due to free() possibly 380 * being called via an IPI message or from sensitive interrupt code. 381 */ 382 while (slgd->NFreeZones > ZONE_RELS_THRESH && (flags & M_NOWAIT) == 0) { 383 crit_enter(); 384 if (slgd->NFreeZones > ZONE_RELS_THRESH) { /* crit sect race */ 385 z = slgd->FreeZones; 386 slgd->FreeZones = z->z_Next; 387 --slgd->NFreeZones; 388 kmem_slab_free(z, ZoneSize); /* may block */ 389 } 390 crit_exit(); 391 } 392 /* 393 * XXX handle oversized frees that were queued from free(). 394 */ 395 while (slgd->FreeOvZones && (flags & M_NOWAIT) == 0) { 396 crit_enter(); 397 if ((z = slgd->FreeOvZones) != NULL) { 398 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC); 399 slgd->FreeOvZones = z->z_Next; 400 kmem_slab_free(z, z->z_ChunkSize); /* may block */ 401 } 402 crit_exit(); 403 } 404 405 /* 406 * Handle large allocations directly. There should not be very many of 407 * these so performance is not a big issue. 408 * 409 * Guarentee page alignment for allocations in multiples of PAGE_SIZE 410 */ 411 if (size >= ZoneLimit || (size & PAGE_MASK) == 0) { 412 struct kmemusage *kup; 413 414 size = round_page(size); 415 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags); 416 if (chunk == NULL) 417 return(NULL); 418 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */ 419 kup = btokup(chunk); 420 kup->ku_pagecnt = size / PAGE_SIZE; 421 crit_enter(); 422 goto done; 423 } 424 425 /* 426 * Attempt to allocate out of an existing zone. First try the free list, 427 * then allocate out of unallocated space. If we find a good zone move 428 * it to the head of the list so later allocations find it quickly 429 * (we might have thousands of zones in the list). 430 * 431 * Note: zoneindex() will panic of size is too large. 432 */ 433 zi = zoneindex(&size); 434 KKASSERT(zi < NZONES); 435 crit_enter(); 436 if ((z = slgd->ZoneAry[zi]) != NULL) { 437 KKASSERT(z->z_NFree > 0); 438 439 /* 440 * Remove us from the ZoneAry[] when we become empty 441 */ 442 if (--z->z_NFree == 0) { 443 slgd->ZoneAry[zi] = z->z_Next; 444 z->z_Next = NULL; 445 } 446 447 /* 448 * Locate a chunk in a free page. This attempts to localize 449 * reallocations into earlier pages without us having to sort 450 * the chunk list. A chunk may still overlap a page boundary. 451 */ 452 while (z->z_FirstFreePg < ZonePageCount) { 453 if ((chunk = z->z_PageAry[z->z_FirstFreePg]) != NULL) { 454 #ifdef DIAGNOSTIC 455 /* 456 * Diagnostic: c_Next is not total garbage. 457 */ 458 KKASSERT(chunk->c_Next == NULL || 459 ((intptr_t)chunk->c_Next & IN_SAME_PAGE_MASK) == 460 ((intptr_t)chunk & IN_SAME_PAGE_MASK)); 461 #endif 462 #ifdef INVARIANTS 463 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS) 464 panic("chunk %p FFPG %d/%d", chunk, z->z_FirstFreePg, ZonePageCount); 465 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS) 466 panic("chunkNEXT %p %p FFPG %d/%d", chunk, chunk->c_Next, z->z_FirstFreePg, ZonePageCount); 467 #endif 468 z->z_PageAry[z->z_FirstFreePg] = chunk->c_Next; 469 goto done; 470 } 471 ++z->z_FirstFreePg; 472 } 473 474 /* 475 * No chunks are available but NFree said we had some memory, so 476 * it must be available in the never-before-used-memory area 477 * governed by UIndex. The consequences are very serious if our zone 478 * got corrupted so we use an explicit panic rather then a KASSERT. 479 */ 480 if (z->z_UIndex + 1 != z->z_NMax) 481 z->z_UIndex = z->z_UIndex + 1; 482 else 483 z->z_UIndex = 0; 484 if (z->z_UIndex == z->z_UEndIndex) 485 panic("slaballoc: corrupted zone"); 486 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 487 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) 488 flags &= ~M_ZERO; 489 goto done; 490 } 491 492 /* 493 * If all zones are exhausted we need to allocate a new zone for this 494 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see 495 * UAlloc use above in regards to M_ZERO. Note that when we are reusing 496 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and 497 * we do not pre-zero it because we do not want to mess up the L1 cache. 498 * 499 * At least one subsystem, the tty code (see CROUND) expects power-of-2 500 * allocations to be power-of-2 aligned. We maintain compatibility by 501 * adjusting the base offset below. 502 */ 503 { 504 int off; 505 506 if ((z = slgd->FreeZones) != NULL) { 507 slgd->FreeZones = z->z_Next; 508 --slgd->NFreeZones; 509 bzero(z, sizeof(SLZone)); 510 z->z_Flags |= SLZF_UNOTZEROD; 511 } else { 512 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO); 513 if (z == NULL) 514 goto fail; 515 } 516 517 /* 518 * Guarentee power-of-2 alignment for power-of-2-sized chunks. 519 * Otherwise just 8-byte align the data. 520 */ 521 if ((size | (size - 1)) + 1 == (size << 1)) 522 off = (sizeof(SLZone) + size - 1) & ~(size - 1); 523 else 524 off = (sizeof(SLZone) + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK; 525 z->z_Magic = ZALLOC_SLAB_MAGIC; 526 z->z_ZoneIndex = zi; 527 z->z_NMax = (ZoneSize - off) / size; 528 z->z_NFree = z->z_NMax - 1; 529 z->z_BasePtr = (char *)z + off; 530 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax; 531 z->z_ChunkSize = size; 532 z->z_FirstFreePg = ZonePageCount; 533 z->z_Cpu = mycpu->gd_cpuid; 534 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 535 z->z_Next = slgd->ZoneAry[zi]; 536 slgd->ZoneAry[zi] = z; 537 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) 538 flags &= ~M_ZERO; /* already zero'd */ 539 540 /* 541 * Slide the base index for initial allocations out of the next 542 * zone we create so we do not over-weight the lower part of the 543 * cpu memory caches. 544 */ 545 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE) 546 & (ZALLOC_MAX_ZONE_SIZE - 1); 547 } 548 done: 549 crit_exit(); 550 if (flags & M_ZERO) 551 bzero(chunk, size); 552 ++type->ks_inuse; 553 type->ks_memuse += size; 554 return(chunk); 555 fail: 556 crit_exit(); 557 return(NULL); 558 } 559 560 void * 561 realloc(void *ptr, unsigned long size, struct malloc_type *type, int flags) 562 { 563 SLZone *z; 564 void *nptr; 565 unsigned long osize; 566 567 if (ptr == NULL || ptr == ZERO_LENGTH_PTR) 568 return(malloc(size, type, flags)); 569 if (size == 0) { 570 free(ptr, type); 571 return(NULL); 572 } 573 574 /* 575 * Handle oversized allocations. XXX we really should require that a 576 * size be passed to free() instead of this nonsense. 577 */ 578 { 579 struct kmemusage *kup; 580 581 kup = btokup(ptr); 582 if (kup->ku_pagecnt) { 583 osize = kup->ku_pagecnt << PAGE_SHIFT; 584 if (osize == round_page(size)) 585 return(ptr); 586 if ((nptr = malloc(size, type, flags)) == NULL) 587 return(NULL); 588 bcopy(ptr, nptr, min(size, osize)); 589 free(ptr, type); 590 return(nptr); 591 } 592 } 593 594 /* 595 * Get the original allocation's zone. If the new request winds up 596 * using the same chunk size we do not have to do anything. 597 */ 598 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask); 599 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 600 601 zoneindex(&size); 602 if (z->z_ChunkSize == size) 603 return(ptr); 604 605 /* 606 * Allocate memory for the new request size. Note that zoneindex has 607 * already adjusted the request size to the appropriate chunk size, which 608 * should optimize our bcopy(). Then copy and return the new pointer. 609 */ 610 if ((nptr = malloc(size, type, flags)) == NULL) 611 return(NULL); 612 bcopy(ptr, nptr, min(size, z->z_ChunkSize)); 613 free(ptr, type); 614 return(nptr); 615 } 616 617 /* 618 * free() (SLAB ALLOCATOR) 619 * 620 * Free the specified chunk of memory. The byte count is not strictly 621 * required but if DIAGNOSTIC is set we use it as a sanity check. 622 */ 623 static 624 void 625 free_remote(void *ptr) 626 { 627 free(ptr, *(struct malloc_type **)ptr); 628 } 629 630 void 631 free(void *ptr, struct malloc_type *type) 632 { 633 SLZone *z; 634 SLChunk *chunk; 635 SLGlobalData *slgd; 636 int pgno; 637 638 slgd = &mycpu->gd_slab; 639 640 /* 641 * Handle special 0-byte allocations 642 */ 643 if (ptr == ZERO_LENGTH_PTR) 644 return; 645 646 /* 647 * Handle oversized allocations. XXX we really should require that a 648 * size be passed to free() instead of this nonsense. 649 */ 650 { 651 struct kmemusage *kup; 652 unsigned long size; 653 654 kup = btokup(ptr); 655 if (kup->ku_pagecnt) { 656 size = kup->ku_pagecnt << PAGE_SHIFT; 657 kup->ku_pagecnt = 0; 658 --type->ks_inuse; 659 type->ks_memuse -= size; 660 #ifdef INVARIANTS 661 KKASSERT(sizeof(weirdary) <= size); 662 bcopy(weirdary, ptr, sizeof(weirdary)); 663 #endif 664 if (mycpu->gd_intr_nesting_level) { 665 crit_enter(); 666 z = (SLZone *)ptr; 667 z->z_Magic = ZALLOC_OVSZ_MAGIC; 668 z->z_Next = slgd->FreeOvZones; 669 z->z_ChunkSize = size; 670 slgd->FreeOvZones = z; 671 crit_exit(); 672 } else { 673 kmem_slab_free(ptr, size); /* may block */ 674 } 675 return; 676 } 677 } 678 679 /* 680 * Zone case. Figure out the zone based on the fact that it is 681 * ZoneSize aligned. 682 */ 683 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask); 684 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 685 686 /* 687 * If we do not own the zone then forward the request to the 688 * cpu that does. The freeing code does not need the byte count 689 * unless DIAGNOSTIC is set. 690 */ 691 if (z->z_Cpu != mycpu->gd_cpuid) { 692 *(struct malloc_type **)ptr = type; 693 lwkt_send_ipiq(z->z_Cpu, free_remote, ptr); 694 return; 695 } 696 697 if (type->ks_magic != M_MAGIC) 698 panic("free: malloc type lacks magic"); 699 700 crit_enter(); 701 pgno = ((char *)ptr - (char *)z) >> PAGE_SHIFT; 702 chunk = ptr; 703 704 #ifdef DIAGNOSTIC 705 /* 706 * Diagnostic: attempt to detect a double-free (not perfect). 707 */ 708 if (((intptr_t)chunk->c_Next - (intptr_t)z) >> PAGE_SHIFT == pgno) { 709 SLChunk *scan; 710 for (scan = z->z_PageAry[pgno]; scan; scan = scan->c_Next) { 711 if (scan == chunk) 712 panic("Double free at %p", chunk); 713 } 714 } 715 #endif 716 717 /* 718 * Put weird data into the memory to detect modifications after freeing, 719 * illegal pointer use after freeing (we should fault on the odd address), 720 * and so forth. XXX needs more work, see the old malloc code. 721 */ 722 #ifdef INVARIANTS 723 if (z->z_ChunkSize < sizeof(weirdary)) 724 bcopy(weirdary, chunk, z->z_ChunkSize); 725 else 726 bcopy(weirdary, chunk, sizeof(weirdary)); 727 #endif 728 729 /* 730 * Add this free non-zero'd chunk to a linked list for reuse, adjust 731 * z_FirstFreePg. 732 */ 733 #ifdef INVARIANTS 734 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS) 735 panic("BADFREE %p\n", chunk); 736 #endif 737 chunk->c_Next = z->z_PageAry[pgno]; 738 z->z_PageAry[pgno] = chunk; 739 #ifdef INVARIANTS 740 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS) 741 panic("BADFREE2"); 742 #endif 743 if (z->z_FirstFreePg > pgno) 744 z->z_FirstFreePg = pgno; 745 746 /* 747 * Bump the number of free chunks. If it becomes non-zero the zone 748 * must be added back onto the appropriate list. 749 */ 750 if (z->z_NFree++ == 0) { 751 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 752 slgd->ZoneAry[z->z_ZoneIndex] = z; 753 } 754 755 --type->ks_inuse; 756 type->ks_memuse -= z->z_ChunkSize; 757 758 /* 759 * If the zone becomes totally free, and there are other zones we 760 * can allocate from, move this zone to the FreeZones list. Since 761 * this code can be called from an IPI callback, do *NOT* try to mess 762 * with kernel_map here. Hysteresis will be performed at malloc() time. 763 */ 764 if (z->z_NFree == z->z_NMax && 765 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) 766 ) { 767 SLZone **pz; 768 769 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next) 770 ; 771 *pz = z->z_Next; 772 z->z_Magic = -1; 773 z->z_Next = slgd->FreeZones; 774 slgd->FreeZones = z; 775 ++slgd->NFreeZones; 776 } 777 crit_exit(); 778 } 779 780 /* 781 * kmem_slab_alloc() 782 * 783 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the 784 * specified alignment. M_* flags are expected in the flags field. 785 * 786 * Alignment must be a multiple of PAGE_SIZE. 787 * 788 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(), 789 * but when we move zalloc() over to use this function as its backend 790 * we will have to switch to kreserve/krelease and call reserve(0) 791 * after the new space is made available. 792 */ 793 static void * 794 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags) 795 { 796 vm_size_t i; 797 vm_offset_t addr; 798 vm_offset_t offset; 799 int count; 800 vm_map_t map = kernel_map; 801 802 size = round_page(size); 803 addr = vm_map_min(map); 804 805 /* 806 * Reserve properly aligned space from kernel_map 807 */ 808 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 809 crit_enter(); 810 vm_map_lock(map); 811 if (vm_map_findspace(map, vm_map_min(map), size, align, &addr)) { 812 vm_map_unlock(map); 813 if ((flags & (M_NOWAIT|M_NULLOK)) == 0) 814 panic("kmem_slab_alloc(): kernel_map ran out of space!"); 815 crit_exit(); 816 vm_map_entry_release(count); 817 return(NULL); 818 } 819 offset = addr - VM_MIN_KERNEL_ADDRESS; 820 vm_object_reference(kernel_object); 821 vm_map_insert(map, &count, 822 kernel_object, offset, addr, addr + size, 823 VM_PROT_ALL, VM_PROT_ALL, 0); 824 825 /* 826 * Allocate the pages. Do not mess with the PG_ZERO flag yet. 827 */ 828 for (i = 0; i < size; i += PAGE_SIZE) { 829 vm_page_t m; 830 vm_pindex_t idx = OFF_TO_IDX(offset + i); 831 int zero = (flags & M_ZERO) ? VM_ALLOC_ZERO : 0; 832 833 if ((flags & (M_NOWAIT|M_USE_RESERVE)) == M_NOWAIT) 834 m = vm_page_alloc(kernel_object, idx, VM_ALLOC_INTERRUPT|zero); 835 else 836 m = vm_page_alloc(kernel_object, idx, VM_ALLOC_SYSTEM|zero); 837 if (m == NULL) { 838 if ((flags & M_NOWAIT) == 0) { 839 vm_map_unlock(map); 840 vm_wait(); 841 vm_map_lock(map); 842 i -= PAGE_SIZE; /* retry */ 843 continue; 844 } 845 while (i != 0) { 846 i -= PAGE_SIZE; 847 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i)); 848 vm_page_free(m); 849 } 850 vm_map_delete(map, addr, addr + size, &count); 851 vm_map_unlock(map); 852 crit_exit(); 853 vm_map_entry_release(count); 854 return(NULL); 855 } 856 } 857 858 /* 859 * Mark the map entry as non-pageable using a routine that allows us to 860 * populate the underlying pages. 861 */ 862 vm_map_set_wired_quick(map, addr, size, &count); 863 crit_exit(); 864 865 /* 866 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO. 867 */ 868 for (i = 0; i < size; i += PAGE_SIZE) { 869 vm_page_t m; 870 871 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i)); 872 m->valid = VM_PAGE_BITS_ALL; 873 vm_page_wire(m); 874 vm_page_wakeup(m); 875 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1); 876 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO)) 877 bzero((char *)addr + i, PAGE_SIZE); 878 vm_page_flag_clear(m, PG_ZERO); 879 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED); 880 } 881 vm_map_unlock(map); 882 vm_map_entry_release(count); 883 return((void *)addr); 884 } 885 886 static void 887 kmem_slab_free(void *ptr, vm_size_t size) 888 { 889 crit_enter(); 890 vm_map_remove(kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size); 891 crit_exit(); 892 } 893 894 #endif 895