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 1.14 2003/10/25 00:48:03 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 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/kernel.h> 89 #include <sys/slaballoc.h> 90 #include <sys/mbuf.h> 91 #include <sys/vmmeter.h> 92 #include <sys/lock.h> 93 #include <sys/thread.h> 94 #include <sys/globaldata.h> 95 96 #include <vm/vm.h> 97 #include <vm/vm_param.h> 98 #include <vm/vm_kern.h> 99 #include <vm/vm_extern.h> 100 #include <vm/vm_object.h> 101 #include <vm/pmap.h> 102 #include <vm/vm_map.h> 103 #include <vm/vm_page.h> 104 #include <vm/vm_pageout.h> 105 106 #include <machine/cpu.h> 107 108 #include <sys/thread2.h> 109 110 #define arysize(ary) (sizeof(ary)/sizeof((ary)[0])) 111 112 /* 113 * Fixed globals (not per-cpu) 114 */ 115 static int ZoneSize; 116 static int ZoneLimit; 117 static int ZonePageCount; 118 static int ZonePageLimit; 119 static int ZoneMask; 120 static struct malloc_type *kmemstatistics; 121 static struct kmemusage *kmemusage; 122 static int32_t weirdary[16]; 123 124 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags); 125 static void kmem_slab_free(void *ptr, vm_size_t bytes); 126 127 /* 128 * Misc constants. Note that allocations that are exact multiples of 129 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module. 130 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists. 131 */ 132 #define MIN_CHUNK_SIZE 8 /* in bytes */ 133 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1) 134 #define ZONE_RELS_THRESH 2 /* threshold number of zones */ 135 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK) 136 137 /* 138 * The WEIRD_ADDR is used as known text to copy into free objects to 139 * try to create deterministic failure cases if the data is accessed after 140 * free. 141 */ 142 #define WEIRD_ADDR 0xdeadc0de 143 #define MAX_COPY sizeof(weirdary) 144 #define ZERO_LENGTH_PTR ((void *)-8) 145 146 /* 147 * Misc global malloc buckets 148 */ 149 150 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches"); 151 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory"); 152 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers"); 153 154 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options"); 155 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery"); 156 157 /* 158 * Initialize the slab memory allocator. We have to choose a zone size based 159 * on available physical memory. We choose a zone side which is approximately 160 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of 161 * 128K. The zone size is limited to the bounds set in slaballoc.h 162 * (typically 32K min, 128K max). 163 */ 164 static void kmeminit(void *dummy); 165 166 SYSINIT(kmem, SI_SUB_KMEM, SI_ORDER_FIRST, kmeminit, NULL) 167 168 static void 169 kmeminit(void *dummy) 170 { 171 vm_poff_t limsize; 172 int usesize; 173 int i; 174 vm_pindex_t npg; 175 176 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE; 177 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) 178 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS; 179 180 usesize = (int)(limsize / 1024); /* convert to KB */ 181 182 ZoneSize = ZALLOC_MIN_ZONE_SIZE; 183 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize) 184 ZoneSize <<= 1; 185 ZoneLimit = ZoneSize / 4; 186 if (ZoneLimit > ZALLOC_ZONE_LIMIT) 187 ZoneLimit = ZALLOC_ZONE_LIMIT; 188 ZoneMask = ZoneSize - 1; 189 ZonePageLimit = PAGE_SIZE * 4; 190 ZonePageCount = ZoneSize / PAGE_SIZE; 191 192 npg = (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) / PAGE_SIZE; 193 kmemusage = kmem_slab_alloc(npg * sizeof(struct kmemusage), PAGE_SIZE, M_ZERO); 194 195 for (i = 0; i < arysize(weirdary); ++i) 196 weirdary[i] = WEIRD_ADDR; 197 198 if (bootverbose) 199 printf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024); 200 } 201 202 /* 203 * Initialize a malloc type tracking structure. 204 */ 205 void 206 malloc_init(void *data) 207 { 208 struct malloc_type *type = data; 209 vm_poff_t limsize; 210 211 if (type->ks_magic != M_MAGIC) 212 panic("malloc type lacks magic"); 213 214 if (type->ks_limit != 0) 215 return; 216 217 if (vmstats.v_page_count == 0) 218 panic("malloc_init not allowed before vm init"); 219 220 limsize = (vm_poff_t)vmstats.v_page_count * PAGE_SIZE; 221 if (limsize > VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) 222 limsize = VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS; 223 type->ks_limit = limsize / 10; 224 225 type->ks_next = kmemstatistics; 226 kmemstatistics = type; 227 } 228 229 void 230 malloc_uninit(void *data) 231 { 232 struct malloc_type *type = data; 233 struct malloc_type *t; 234 #ifdef INVARIANTS 235 int i; 236 long ttl; 237 #endif 238 239 if (type->ks_magic != M_MAGIC) 240 panic("malloc type lacks magic"); 241 242 if (vmstats.v_page_count == 0) 243 panic("malloc_uninit not allowed before vm init"); 244 245 if (type->ks_limit == 0) 246 panic("malloc_uninit on uninitialized type"); 247 248 #ifdef INVARIANTS 249 /* 250 * memuse is only correct in aggregation. Due to memory being allocated 251 * on one cpu and freed on another individual array entries may be 252 * negative or positive (canceling each other out). 253 */ 254 for (i = ttl = 0; i < ncpus; ++i) 255 ttl += type->ks_memuse[i]; 256 if (ttl) { 257 printf("malloc_uninit: %ld bytes of '%s' still allocated on cpu %d\n", 258 ttl, type->ks_shortdesc, i); 259 } 260 #endif 261 if (type == kmemstatistics) { 262 kmemstatistics = type->ks_next; 263 } else { 264 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) { 265 if (t->ks_next == type) { 266 t->ks_next = type->ks_next; 267 break; 268 } 269 } 270 } 271 type->ks_next = NULL; 272 type->ks_limit = 0; 273 } 274 275 /* 276 * Calculate the zone index for the allocation request size and set the 277 * allocation request size to that particular zone's chunk size. 278 */ 279 static __inline int 280 zoneindex(unsigned long *bytes) 281 { 282 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */ 283 if (n < 128) { 284 *bytes = n = (n + 7) & ~7; 285 return(n / 8 - 1); /* 8 byte chunks, 16 zones */ 286 } 287 if (n < 256) { 288 *bytes = n = (n + 15) & ~15; 289 return(n / 16 + 7); 290 } 291 if (n < 8192) { 292 if (n < 512) { 293 *bytes = n = (n + 31) & ~31; 294 return(n / 32 + 15); 295 } 296 if (n < 1024) { 297 *bytes = n = (n + 63) & ~63; 298 return(n / 64 + 23); 299 } 300 if (n < 2048) { 301 *bytes = n = (n + 127) & ~127; 302 return(n / 128 + 31); 303 } 304 if (n < 4096) { 305 *bytes = n = (n + 255) & ~255; 306 return(n / 256 + 39); 307 } 308 *bytes = n = (n + 511) & ~511; 309 return(n / 512 + 47); 310 } 311 #if ZALLOC_ZONE_LIMIT > 8192 312 if (n < 16384) { 313 *bytes = n = (n + 1023) & ~1023; 314 return(n / 1024 + 55); 315 } 316 #endif 317 #if ZALLOC_ZONE_LIMIT > 16384 318 if (n < 32768) { 319 *bytes = n = (n + 2047) & ~2047; 320 return(n / 2048 + 63); 321 } 322 #endif 323 panic("Unexpected byte count %d", n); 324 return(0); 325 } 326 327 /* 328 * malloc() (SLAB ALLOCATOR) 329 * 330 * Allocate memory via the slab allocator. If the request is too large, 331 * or if it page-aligned beyond a certain size, we fall back to the 332 * KMEM subsystem. A SLAB tracking descriptor must be specified, use 333 * &SlabMisc if you don't care. 334 * 335 * M_NOWAIT - return NULL instead of blocking. 336 * M_ZERO - zero the returned memory. 337 * M_USE_RESERVE - allocate out of the system reserve if necessary 338 */ 339 void * 340 malloc(unsigned long size, struct malloc_type *type, int flags) 341 { 342 SLZone *z; 343 SLChunk *chunk; 344 SLGlobalData *slgd; 345 struct globaldata *gd; 346 int zi; 347 348 gd = mycpu; 349 slgd = &gd->gd_slab; 350 351 /* 352 * XXX silly to have this in the critical path. 353 */ 354 if (type->ks_limit == 0) { 355 crit_enter(); 356 if (type->ks_limit == 0) 357 malloc_init(type); 358 crit_exit(); 359 } 360 ++type->ks_calls; 361 362 /* 363 * Handle the case where the limit is reached. Panic if can't return 364 * NULL. XXX the original malloc code looped, but this tended to 365 * simply deadlock the computer. 366 */ 367 while (type->ks_loosememuse >= type->ks_limit) { 368 int i; 369 long ttl; 370 371 for (i = ttl = 0; i < ncpus; ++i) 372 ttl += type->ks_memuse[i]; 373 type->ks_loosememuse = ttl; 374 if (ttl >= type->ks_limit) { 375 if (flags & (M_NOWAIT|M_NULLOK)) 376 return(NULL); 377 panic("%s: malloc limit exceeded", type->ks_shortdesc); 378 } 379 } 380 381 /* 382 * Handle the degenerate size == 0 case. Yes, this does happen. 383 * Return a special pointer. This is to maintain compatibility with 384 * the original malloc implementation. Certain devices, such as the 385 * adaptec driver, not only allocate 0 bytes, they check for NULL and 386 * also realloc() later on. Joy. 387 */ 388 if (size == 0) 389 return(ZERO_LENGTH_PTR); 390 391 /* 392 * Handle hysteresis from prior frees here in malloc(). We cannot 393 * safely manipulate the kernel_map in free() due to free() possibly 394 * being called via an IPI message or from sensitive interrupt code. 395 */ 396 while (slgd->NFreeZones > ZONE_RELS_THRESH && (flags & M_NOWAIT) == 0) { 397 crit_enter(); 398 if (slgd->NFreeZones > ZONE_RELS_THRESH) { /* crit sect race */ 399 z = slgd->FreeZones; 400 slgd->FreeZones = z->z_Next; 401 --slgd->NFreeZones; 402 kmem_slab_free(z, ZoneSize); /* may block */ 403 } 404 crit_exit(); 405 } 406 /* 407 * XXX handle oversized frees that were queued from free(). 408 */ 409 while (slgd->FreeOvZones && (flags & M_NOWAIT) == 0) { 410 crit_enter(); 411 if ((z = slgd->FreeOvZones) != NULL) { 412 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC); 413 slgd->FreeOvZones = z->z_Next; 414 kmem_slab_free(z, z->z_ChunkSize); /* may block */ 415 } 416 crit_exit(); 417 } 418 419 /* 420 * Handle large allocations directly. There should not be very many of 421 * these so performance is not a big issue. 422 * 423 * Guarentee page alignment for allocations in multiples of PAGE_SIZE 424 */ 425 if (size >= ZoneLimit || (size & PAGE_MASK) == 0) { 426 struct kmemusage *kup; 427 428 size = round_page(size); 429 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags); 430 if (chunk == NULL) 431 return(NULL); 432 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */ 433 flags |= M_PASSIVE_ZERO; 434 kup = btokup(chunk); 435 kup->ku_pagecnt = size / PAGE_SIZE; 436 kup->ku_cpu = gd->gd_cpuid; 437 crit_enter(); 438 goto done; 439 } 440 441 /* 442 * Attempt to allocate out of an existing zone. First try the free list, 443 * then allocate out of unallocated space. If we find a good zone move 444 * it to the head of the list so later allocations find it quickly 445 * (we might have thousands of zones in the list). 446 * 447 * Note: zoneindex() will panic of size is too large. 448 */ 449 zi = zoneindex(&size); 450 KKASSERT(zi < NZONES); 451 crit_enter(); 452 if ((z = slgd->ZoneAry[zi]) != NULL) { 453 KKASSERT(z->z_NFree > 0); 454 455 /* 456 * Remove us from the ZoneAry[] when we become empty 457 */ 458 if (--z->z_NFree == 0) { 459 slgd->ZoneAry[zi] = z->z_Next; 460 z->z_Next = NULL; 461 } 462 463 /* 464 * Locate a chunk in a free page. This attempts to localize 465 * reallocations into earlier pages without us having to sort 466 * the chunk list. A chunk may still overlap a page boundary. 467 */ 468 while (z->z_FirstFreePg < ZonePageCount) { 469 if ((chunk = z->z_PageAry[z->z_FirstFreePg]) != NULL) { 470 #ifdef DIAGNOSTIC 471 /* 472 * Diagnostic: c_Next is not total garbage. 473 */ 474 KKASSERT(chunk->c_Next == NULL || 475 ((intptr_t)chunk->c_Next & IN_SAME_PAGE_MASK) == 476 ((intptr_t)chunk & IN_SAME_PAGE_MASK)); 477 #endif 478 #ifdef INVARIANTS 479 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS) 480 panic("chunk %p FFPG %d/%d", chunk, z->z_FirstFreePg, ZonePageCount); 481 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS) 482 panic("chunkNEXT %p %p FFPG %d/%d", chunk, chunk->c_Next, z->z_FirstFreePg, ZonePageCount); 483 #endif 484 z->z_PageAry[z->z_FirstFreePg] = chunk->c_Next; 485 goto done; 486 } 487 ++z->z_FirstFreePg; 488 } 489 490 /* 491 * No chunks are available but NFree said we had some memory, so 492 * it must be available in the never-before-used-memory area 493 * governed by UIndex. The consequences are very serious if our zone 494 * got corrupted so we use an explicit panic rather then a KASSERT. 495 */ 496 if (z->z_UIndex + 1 != z->z_NMax) 497 z->z_UIndex = z->z_UIndex + 1; 498 else 499 z->z_UIndex = 0; 500 if (z->z_UIndex == z->z_UEndIndex) 501 panic("slaballoc: corrupted zone"); 502 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 503 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 504 flags &= ~M_ZERO; 505 flags |= M_PASSIVE_ZERO; 506 } 507 goto done; 508 } 509 510 /* 511 * If all zones are exhausted we need to allocate a new zone for this 512 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see 513 * UAlloc use above in regards to M_ZERO. Note that when we are reusing 514 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and 515 * we do not pre-zero it because we do not want to mess up the L1 cache. 516 * 517 * At least one subsystem, the tty code (see CROUND) expects power-of-2 518 * allocations to be power-of-2 aligned. We maintain compatibility by 519 * adjusting the base offset below. 520 */ 521 { 522 int off; 523 524 if ((z = slgd->FreeZones) != NULL) { 525 slgd->FreeZones = z->z_Next; 526 --slgd->NFreeZones; 527 bzero(z, sizeof(SLZone)); 528 z->z_Flags |= SLZF_UNOTZEROD; 529 } else { 530 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO); 531 if (z == NULL) 532 goto fail; 533 } 534 535 /* 536 * Guarentee power-of-2 alignment for power-of-2-sized chunks. 537 * Otherwise just 8-byte align the data. 538 */ 539 if ((size | (size - 1)) + 1 == (size << 1)) 540 off = (sizeof(SLZone) + size - 1) & ~(size - 1); 541 else 542 off = (sizeof(SLZone) + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK; 543 z->z_Magic = ZALLOC_SLAB_MAGIC; 544 z->z_ZoneIndex = zi; 545 z->z_NMax = (ZoneSize - off) / size; 546 z->z_NFree = z->z_NMax - 1; 547 z->z_BasePtr = (char *)z + off; 548 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax; 549 z->z_ChunkSize = size; 550 z->z_FirstFreePg = ZonePageCount; 551 z->z_Cpu = gd->gd_cpuid; 552 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 553 z->z_Next = slgd->ZoneAry[zi]; 554 slgd->ZoneAry[zi] = z; 555 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 556 flags &= ~M_ZERO; /* already zero'd */ 557 flags |= M_PASSIVE_ZERO; 558 } 559 560 /* 561 * Slide the base index for initial allocations out of the next 562 * zone we create so we do not over-weight the lower part of the 563 * cpu memory caches. 564 */ 565 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE) 566 & (ZALLOC_MAX_ZONE_SIZE - 1); 567 } 568 done: 569 ++type->ks_inuse[gd->gd_cpuid]; 570 type->ks_memuse[gd->gd_cpuid] += size; 571 type->ks_loosememuse += size; 572 crit_exit(); 573 if (flags & M_ZERO) 574 bzero(chunk, size); 575 #ifdef INVARIANTS 576 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0) 577 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */ 578 #endif 579 return(chunk); 580 fail: 581 crit_exit(); 582 return(NULL); 583 } 584 585 void * 586 realloc(void *ptr, unsigned long size, struct malloc_type *type, int flags) 587 { 588 SLZone *z; 589 void *nptr; 590 unsigned long osize; 591 592 if (ptr == NULL || ptr == ZERO_LENGTH_PTR) 593 return(malloc(size, type, flags)); 594 if (size == 0) { 595 free(ptr, type); 596 return(NULL); 597 } 598 599 /* 600 * Handle oversized allocations. XXX we really should require that a 601 * size be passed to free() instead of this nonsense. 602 */ 603 { 604 struct kmemusage *kup; 605 606 kup = btokup(ptr); 607 if (kup->ku_pagecnt) { 608 osize = kup->ku_pagecnt << PAGE_SHIFT; 609 if (osize == round_page(size)) 610 return(ptr); 611 if ((nptr = malloc(size, type, flags)) == NULL) 612 return(NULL); 613 bcopy(ptr, nptr, min(size, osize)); 614 free(ptr, type); 615 return(nptr); 616 } 617 } 618 619 /* 620 * Get the original allocation's zone. If the new request winds up 621 * using the same chunk size we do not have to do anything. 622 */ 623 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask); 624 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 625 626 zoneindex(&size); 627 if (z->z_ChunkSize == size) 628 return(ptr); 629 630 /* 631 * Allocate memory for the new request size. Note that zoneindex has 632 * already adjusted the request size to the appropriate chunk size, which 633 * should optimize our bcopy(). Then copy and return the new pointer. 634 */ 635 if ((nptr = malloc(size, type, flags)) == NULL) 636 return(NULL); 637 bcopy(ptr, nptr, min(size, z->z_ChunkSize)); 638 free(ptr, type); 639 return(nptr); 640 } 641 642 #ifdef SMP 643 /* 644 * free() (SLAB ALLOCATOR) 645 * 646 * Free the specified chunk of memory. 647 */ 648 static 649 void 650 free_remote(void *ptr) 651 { 652 free(ptr, *(struct malloc_type **)ptr); 653 } 654 655 #endif 656 657 void 658 free(void *ptr, struct malloc_type *type) 659 { 660 SLZone *z; 661 SLChunk *chunk; 662 SLGlobalData *slgd; 663 struct globaldata *gd; 664 int pgno; 665 666 gd = mycpu; 667 slgd = &gd->gd_slab; 668 669 /* 670 * Handle special 0-byte allocations 671 */ 672 if (ptr == ZERO_LENGTH_PTR) 673 return; 674 675 /* 676 * Handle oversized allocations. XXX we really should require that a 677 * size be passed to free() instead of this nonsense. 678 * 679 * This code is never called via an ipi. 680 */ 681 { 682 struct kmemusage *kup; 683 unsigned long size; 684 685 kup = btokup(ptr); 686 if (kup->ku_pagecnt) { 687 size = kup->ku_pagecnt << PAGE_SHIFT; 688 kup->ku_pagecnt = 0; 689 #ifdef INVARIANTS 690 KKASSERT(sizeof(weirdary) <= size); 691 bcopy(weirdary, ptr, sizeof(weirdary)); 692 #endif 693 /* 694 * note: we always adjust our cpu's slot, not the originating 695 * cpu (kup->ku_cpuid). The statistics are in aggregate. 696 * 697 * note: XXX we have still inherited the interrupts-can't-block 698 * assumption. An interrupt thread does not bump 699 * gd_intr_nesting_level so check TDF_INTTHREAD. This is 700 * primarily until we can fix softupdate's assumptions about free(). 701 */ 702 crit_enter(); 703 --type->ks_inuse[gd->gd_cpuid]; 704 type->ks_memuse[gd->gd_cpuid] -= size; 705 if (mycpu->gd_intr_nesting_level || (gd->gd_curthread->td_flags & TDF_INTTHREAD)) { 706 z = (SLZone *)ptr; 707 z->z_Magic = ZALLOC_OVSZ_MAGIC; 708 z->z_Next = slgd->FreeOvZones; 709 z->z_ChunkSize = size; 710 slgd->FreeOvZones = z; 711 crit_exit(); 712 } else { 713 crit_exit(); 714 kmem_slab_free(ptr, size); /* may block */ 715 } 716 return; 717 } 718 } 719 720 /* 721 * Zone case. Figure out the zone based on the fact that it is 722 * ZoneSize aligned. 723 */ 724 z = (SLZone *)((uintptr_t)ptr & ~(uintptr_t)ZoneMask); 725 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 726 727 /* 728 * If we do not own the zone then forward the request to the 729 * cpu that does. The freeing code does not need the byte count 730 * unless DIAGNOSTIC is set. 731 */ 732 if (z->z_Cpu != gd->gd_cpuid) { 733 *(struct malloc_type **)ptr = type; 734 #ifdef SMP 735 lwkt_send_ipiq(z->z_Cpu, free_remote, ptr); 736 #else 737 panic("Corrupt SLZone"); 738 #endif 739 return; 740 } 741 742 if (type->ks_magic != M_MAGIC) 743 panic("free: malloc type lacks magic"); 744 745 crit_enter(); 746 pgno = ((char *)ptr - (char *)z) >> PAGE_SHIFT; 747 chunk = ptr; 748 749 #ifdef INVARIANTS 750 /* 751 * Attempt to detect a double-free. To reduce overhead we only check 752 * if there appears to be link pointer at the base of the data. 753 */ 754 if (((intptr_t)chunk->c_Next - (intptr_t)z) >> PAGE_SHIFT == pgno) { 755 SLChunk *scan; 756 for (scan = z->z_PageAry[pgno]; scan; scan = scan->c_Next) { 757 if (scan == chunk) 758 panic("Double free at %p", chunk); 759 } 760 } 761 #endif 762 763 /* 764 * Put weird data into the memory to detect modifications after freeing, 765 * illegal pointer use after freeing (we should fault on the odd address), 766 * and so forth. XXX needs more work, see the old malloc code. 767 */ 768 #ifdef INVARIANTS 769 if (z->z_ChunkSize < sizeof(weirdary)) 770 bcopy(weirdary, chunk, z->z_ChunkSize); 771 else 772 bcopy(weirdary, chunk, sizeof(weirdary)); 773 #endif 774 775 /* 776 * Add this free non-zero'd chunk to a linked list for reuse, adjust 777 * z_FirstFreePg. 778 */ 779 #ifdef INVARIANTS 780 if ((uintptr_t)chunk < VM_MIN_KERNEL_ADDRESS) 781 panic("BADFREE %p\n", chunk); 782 #endif 783 chunk->c_Next = z->z_PageAry[pgno]; 784 z->z_PageAry[pgno] = chunk; 785 #ifdef INVARIANTS 786 if (chunk->c_Next && (uintptr_t)chunk->c_Next < VM_MIN_KERNEL_ADDRESS) 787 panic("BADFREE2"); 788 #endif 789 if (z->z_FirstFreePg > pgno) 790 z->z_FirstFreePg = pgno; 791 792 /* 793 * Bump the number of free chunks. If it becomes non-zero the zone 794 * must be added back onto the appropriate list. 795 */ 796 if (z->z_NFree++ == 0) { 797 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 798 slgd->ZoneAry[z->z_ZoneIndex] = z; 799 } 800 801 --type->ks_inuse[z->z_Cpu]; 802 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize; 803 804 /* 805 * If the zone becomes totally free, and there are other zones we 806 * can allocate from, move this zone to the FreeZones list. Since 807 * this code can be called from an IPI callback, do *NOT* try to mess 808 * with kernel_map here. Hysteresis will be performed at malloc() time. 809 */ 810 if (z->z_NFree == z->z_NMax && 811 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) 812 ) { 813 SLZone **pz; 814 815 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next) 816 ; 817 *pz = z->z_Next; 818 z->z_Magic = -1; 819 z->z_Next = slgd->FreeZones; 820 slgd->FreeZones = z; 821 ++slgd->NFreeZones; 822 } 823 crit_exit(); 824 } 825 826 /* 827 * kmem_slab_alloc() 828 * 829 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the 830 * specified alignment. M_* flags are expected in the flags field. 831 * 832 * Alignment must be a multiple of PAGE_SIZE. 833 * 834 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(), 835 * but when we move zalloc() over to use this function as its backend 836 * we will have to switch to kreserve/krelease and call reserve(0) 837 * after the new space is made available. 838 */ 839 static void * 840 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags) 841 { 842 vm_size_t i; 843 vm_offset_t addr; 844 vm_offset_t offset; 845 int count; 846 vm_map_t map = kernel_map; 847 848 size = round_page(size); 849 addr = vm_map_min(map); 850 851 /* 852 * Reserve properly aligned space from kernel_map 853 */ 854 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 855 crit_enter(); 856 vm_map_lock(map); 857 if (vm_map_findspace(map, vm_map_min(map), size, align, &addr)) { 858 vm_map_unlock(map); 859 if ((flags & (M_NOWAIT|M_NULLOK)) == 0) 860 panic("kmem_slab_alloc(): kernel_map ran out of space!"); 861 crit_exit(); 862 vm_map_entry_release(count); 863 return(NULL); 864 } 865 offset = addr - VM_MIN_KERNEL_ADDRESS; 866 vm_object_reference(kernel_object); 867 vm_map_insert(map, &count, 868 kernel_object, offset, addr, addr + size, 869 VM_PROT_ALL, VM_PROT_ALL, 0); 870 871 /* 872 * Allocate the pages. Do not mess with the PG_ZERO flag yet. 873 */ 874 for (i = 0; i < size; i += PAGE_SIZE) { 875 vm_page_t m; 876 vm_pindex_t idx = OFF_TO_IDX(offset + i); 877 int zero = (flags & M_ZERO) ? VM_ALLOC_ZERO : 0; 878 879 if ((flags & (M_NOWAIT|M_USE_RESERVE)) == M_NOWAIT) 880 m = vm_page_alloc(kernel_object, idx, VM_ALLOC_INTERRUPT|zero); 881 else 882 m = vm_page_alloc(kernel_object, idx, VM_ALLOC_SYSTEM|zero); 883 if (m == NULL) { 884 if ((flags & M_NOWAIT) == 0) { 885 vm_map_unlock(map); 886 vm_wait(); 887 vm_map_lock(map); 888 i -= PAGE_SIZE; /* retry */ 889 continue; 890 } 891 while (i != 0) { 892 i -= PAGE_SIZE; 893 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i)); 894 vm_page_free(m); 895 } 896 vm_map_delete(map, addr, addr + size, &count); 897 vm_map_unlock(map); 898 crit_exit(); 899 vm_map_entry_release(count); 900 return(NULL); 901 } 902 } 903 904 /* 905 * Mark the map entry as non-pageable using a routine that allows us to 906 * populate the underlying pages. 907 */ 908 vm_map_set_wired_quick(map, addr, size, &count); 909 crit_exit(); 910 911 /* 912 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO. 913 */ 914 for (i = 0; i < size; i += PAGE_SIZE) { 915 vm_page_t m; 916 917 m = vm_page_lookup(kernel_object, OFF_TO_IDX(offset + i)); 918 m->valid = VM_PAGE_BITS_ALL; 919 vm_page_wire(m); 920 vm_page_wakeup(m); 921 pmap_enter(kernel_pmap, addr + i, m, VM_PROT_ALL, 1); 922 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO)) 923 bzero((char *)addr + i, PAGE_SIZE); 924 vm_page_flag_clear(m, PG_ZERO); 925 vm_page_flag_set(m, PG_MAPPED | PG_WRITEABLE | PG_REFERENCED); 926 } 927 vm_map_unlock(map); 928 vm_map_entry_release(count); 929 return((void *)addr); 930 } 931 932 static void 933 kmem_slab_free(void *ptr, vm_size_t size) 934 { 935 crit_enter(); 936 vm_map_remove(kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size); 937 crit_exit(); 938 } 939 940