1 /* 2 * (MPSAFE) 3 * 4 * KERN_SLABALLOC.C - Kernel SLAB memory allocator 5 * 6 * Copyright (c) 2003,2004,2010 The DragonFly Project. All rights reserved. 7 * 8 * This code is derived from software contributed to The DragonFly Project 9 * by Matthew Dillon <dillon@backplane.com> 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in 19 * the documentation and/or other materials provided with the 20 * distribution. 21 * 3. Neither the name of The DragonFly Project nor the names of its 22 * contributors may be used to endorse or promote products derived 23 * from this software without specific, prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 28 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 29 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 31 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 32 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 33 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * $DragonFly: src/sys/kern/kern_slaballoc.c,v 1.55 2008/10/22 01:42:17 dillon Exp $ 39 * 40 * This module implements a slab allocator drop-in replacement for the 41 * kernel malloc(). 42 * 43 * A slab allocator reserves a ZONE for each chunk size, then lays the 44 * chunks out in an array within the zone. Allocation and deallocation 45 * is nearly instantanious, and fragmentation/overhead losses are limited 46 * to a fixed worst-case amount. 47 * 48 * The downside of this slab implementation is in the chunk size 49 * multiplied by the number of zones. ~80 zones * 128K = 10MB of VM per cpu. 50 * In a kernel implementation all this memory will be physical so 51 * the zone size is adjusted downward on machines with less physical 52 * memory. The upside is that overhead is bounded... this is the *worst* 53 * case overhead. 54 * 55 * Slab management is done on a per-cpu basis and no locking or mutexes 56 * are required, only a critical section. When one cpu frees memory 57 * belonging to another cpu's slab manager an asynchronous IPI message 58 * will be queued to execute the operation. In addition, both the 59 * high level slab allocator and the low level zone allocator optimize 60 * M_ZERO requests, and the slab allocator does not have to pre initialize 61 * the linked list of chunks. 62 * 63 * XXX Balancing is needed between cpus. Balance will be handled through 64 * asynchronous IPIs primarily by reassigning the z_Cpu ownership of chunks. 65 * 66 * XXX If we have to allocate a new zone and M_USE_RESERVE is set, use of 67 * the new zone should be restricted to M_USE_RESERVE requests only. 68 * 69 * Alloc Size Chunking Number of zones 70 * 0-127 8 16 71 * 128-255 16 8 72 * 256-511 32 8 73 * 512-1023 64 8 74 * 1024-2047 128 8 75 * 2048-4095 256 8 76 * 4096-8191 512 8 77 * 8192-16383 1024 8 78 * 16384-32767 2048 8 79 * (if PAGE_SIZE is 4K the maximum zone allocation is 16383) 80 * 81 * Allocations >= ZoneLimit go directly to kmem. 82 * 83 * API REQUIREMENTS AND SIDE EFFECTS 84 * 85 * To operate as a drop-in replacement to the FreeBSD-4.x malloc() we 86 * have remained compatible with the following API requirements: 87 * 88 * + small power-of-2 sized allocations are power-of-2 aligned (kern_tty) 89 * + all power-of-2 sized allocations are power-of-2 aligned (twe) 90 * + malloc(0) is allowed and returns non-NULL (ahc driver) 91 * + ability to allocate arbitrarily large chunks of memory 92 */ 93 94 #include "opt_vm.h" 95 96 #include <sys/param.h> 97 #include <sys/systm.h> 98 #include <sys/kernel.h> 99 #include <sys/slaballoc.h> 100 #include <sys/mbuf.h> 101 #include <sys/vmmeter.h> 102 #include <sys/lock.h> 103 #include <sys/thread.h> 104 #include <sys/globaldata.h> 105 #include <sys/sysctl.h> 106 #include <sys/ktr.h> 107 108 #include <vm/vm.h> 109 #include <vm/vm_param.h> 110 #include <vm/vm_kern.h> 111 #include <vm/vm_extern.h> 112 #include <vm/vm_object.h> 113 #include <vm/pmap.h> 114 #include <vm/vm_map.h> 115 #include <vm/vm_page.h> 116 #include <vm/vm_pageout.h> 117 118 #include <machine/cpu.h> 119 120 #include <sys/thread2.h> 121 122 #define arysize(ary) (sizeof(ary)/sizeof((ary)[0])) 123 124 #define MEMORY_STRING "ptr=%p type=%p size=%d flags=%04x" 125 #define MEMORY_ARG_SIZE (sizeof(void *) * 2 + sizeof(unsigned long) + \ 126 sizeof(int)) 127 128 #if !defined(KTR_MEMORY) 129 #define KTR_MEMORY KTR_ALL 130 #endif 131 KTR_INFO_MASTER(memory); 132 KTR_INFO(KTR_MEMORY, memory, malloc_beg, 0, "malloc begin", 0); 133 KTR_INFO(KTR_MEMORY, memory, malloc_end, 1, MEMORY_STRING, MEMORY_ARG_SIZE); 134 KTR_INFO(KTR_MEMORY, memory, free_zero, 2, MEMORY_STRING, MEMORY_ARG_SIZE); 135 KTR_INFO(KTR_MEMORY, memory, free_ovsz, 3, MEMORY_STRING, MEMORY_ARG_SIZE); 136 KTR_INFO(KTR_MEMORY, memory, free_ovsz_delayed, 4, MEMORY_STRING, MEMORY_ARG_SIZE); 137 KTR_INFO(KTR_MEMORY, memory, free_chunk, 5, MEMORY_STRING, MEMORY_ARG_SIZE); 138 #ifdef SMP 139 KTR_INFO(KTR_MEMORY, memory, free_request, 6, MEMORY_STRING, MEMORY_ARG_SIZE); 140 KTR_INFO(KTR_MEMORY, memory, free_rem_beg, 7, MEMORY_STRING, MEMORY_ARG_SIZE); 141 KTR_INFO(KTR_MEMORY, memory, free_rem_end, 8, MEMORY_STRING, MEMORY_ARG_SIZE); 142 #endif 143 KTR_INFO(KTR_MEMORY, memory, free_beg, 9, "free begin", 0); 144 KTR_INFO(KTR_MEMORY, memory, free_end, 10, "free end", 0); 145 146 #define logmemory(name, ptr, type, size, flags) \ 147 KTR_LOG(memory_ ## name, ptr, type, size, flags) 148 #define logmemory_quick(name) \ 149 KTR_LOG(memory_ ## name) 150 151 /* 152 * Fixed globals (not per-cpu) 153 */ 154 static int ZoneSize; 155 static int ZoneLimit; 156 static int ZonePageCount; 157 static uintptr_t ZoneMask; 158 static int ZoneBigAlloc; /* in KB */ 159 static int ZoneGenAlloc; /* in KB */ 160 struct malloc_type *kmemstatistics; /* exported to vmstat */ 161 static struct kmemusage *kmemusage; 162 static int32_t weirdary[16]; 163 164 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags); 165 static void kmem_slab_free(void *ptr, vm_size_t bytes); 166 167 #if defined(INVARIANTS) 168 static void chunk_mark_allocated(SLZone *z, void *chunk); 169 static void chunk_mark_free(SLZone *z, void *chunk); 170 #else 171 #define chunk_mark_allocated(z, chunk) 172 #define chunk_mark_free(z, chunk) 173 #endif 174 175 /* 176 * Misc constants. Note that allocations that are exact multiples of 177 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module. 178 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists. 179 */ 180 #define MIN_CHUNK_SIZE 8 /* in bytes */ 181 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1) 182 #define ZONE_RELS_THRESH 2 /* threshold number of zones */ 183 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK) 184 185 /* 186 * The WEIRD_ADDR is used as known text to copy into free objects to 187 * try to create deterministic failure cases if the data is accessed after 188 * free. 189 */ 190 #define WEIRD_ADDR 0xdeadc0de 191 #define MAX_COPY sizeof(weirdary) 192 #define ZERO_LENGTH_PTR ((void *)-8) 193 194 /* 195 * Misc global malloc buckets 196 */ 197 198 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches"); 199 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory"); 200 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers"); 201 202 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options"); 203 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery"); 204 205 /* 206 * Initialize the slab memory allocator. We have to choose a zone size based 207 * on available physical memory. We choose a zone side which is approximately 208 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of 209 * 128K. The zone size is limited to the bounds set in slaballoc.h 210 * (typically 32K min, 128K max). 211 */ 212 static void kmeminit(void *dummy); 213 214 char *ZeroPage; 215 216 SYSINIT(kmem, SI_BOOT1_ALLOCATOR, SI_ORDER_FIRST, kmeminit, NULL) 217 218 #ifdef INVARIANTS 219 /* 220 * If enabled any memory allocated without M_ZERO is initialized to -1. 221 */ 222 static int use_malloc_pattern; 223 SYSCTL_INT(_debug, OID_AUTO, use_malloc_pattern, CTLFLAG_RW, 224 &use_malloc_pattern, 0, ""); 225 #endif 226 227 SYSCTL_INT(_kern, OID_AUTO, zone_big_alloc, CTLFLAG_RD, &ZoneBigAlloc, 0, ""); 228 SYSCTL_INT(_kern, OID_AUTO, zone_gen_alloc, CTLFLAG_RD, &ZoneGenAlloc, 0, ""); 229 230 static void 231 kmeminit(void *dummy) 232 { 233 size_t limsize; 234 int usesize; 235 int i; 236 vm_offset_t npg; 237 238 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE; 239 if (limsize > KvaSize) 240 limsize = KvaSize; 241 242 usesize = (int)(limsize / 1024); /* convert to KB */ 243 244 ZoneSize = ZALLOC_MIN_ZONE_SIZE; 245 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize) 246 ZoneSize <<= 1; 247 ZoneLimit = ZoneSize / 4; 248 if (ZoneLimit > ZALLOC_ZONE_LIMIT) 249 ZoneLimit = ZALLOC_ZONE_LIMIT; 250 ZoneMask = ~(uintptr_t)(ZoneSize - 1); 251 ZonePageCount = ZoneSize / PAGE_SIZE; 252 253 npg = KvaSize / PAGE_SIZE; 254 kmemusage = kmem_slab_alloc(npg * sizeof(struct kmemusage), 255 PAGE_SIZE, M_WAITOK|M_ZERO); 256 257 for (i = 0; i < arysize(weirdary); ++i) 258 weirdary[i] = WEIRD_ADDR; 259 260 ZeroPage = kmem_slab_alloc(PAGE_SIZE, PAGE_SIZE, M_WAITOK|M_ZERO); 261 262 if (bootverbose) 263 kprintf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024); 264 } 265 266 /* 267 * Initialize a malloc type tracking structure. 268 */ 269 void 270 malloc_init(void *data) 271 { 272 struct malloc_type *type = data; 273 size_t limsize; 274 275 if (type->ks_magic != M_MAGIC) 276 panic("malloc type lacks magic"); 277 278 if (type->ks_limit != 0) 279 return; 280 281 if (vmstats.v_page_count == 0) 282 panic("malloc_init not allowed before vm init"); 283 284 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE; 285 if (limsize > KvaSize) 286 limsize = KvaSize; 287 type->ks_limit = limsize / 10; 288 289 type->ks_next = kmemstatistics; 290 kmemstatistics = type; 291 } 292 293 void 294 malloc_uninit(void *data) 295 { 296 struct malloc_type *type = data; 297 struct malloc_type *t; 298 #ifdef INVARIANTS 299 int i; 300 long ttl; 301 #endif 302 303 if (type->ks_magic != M_MAGIC) 304 panic("malloc type lacks magic"); 305 306 if (vmstats.v_page_count == 0) 307 panic("malloc_uninit not allowed before vm init"); 308 309 if (type->ks_limit == 0) 310 panic("malloc_uninit on uninitialized type"); 311 312 #ifdef SMP 313 /* Make sure that all pending kfree()s are finished. */ 314 lwkt_synchronize_ipiqs("muninit"); 315 #endif 316 317 #ifdef INVARIANTS 318 /* 319 * memuse is only correct in aggregation. Due to memory being allocated 320 * on one cpu and freed on another individual array entries may be 321 * negative or positive (canceling each other out). 322 */ 323 for (i = ttl = 0; i < ncpus; ++i) 324 ttl += type->ks_memuse[i]; 325 if (ttl) { 326 kprintf("malloc_uninit: %ld bytes of '%s' still allocated on cpu %d\n", 327 ttl, type->ks_shortdesc, i); 328 } 329 #endif 330 if (type == kmemstatistics) { 331 kmemstatistics = type->ks_next; 332 } else { 333 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) { 334 if (t->ks_next == type) { 335 t->ks_next = type->ks_next; 336 break; 337 } 338 } 339 } 340 type->ks_next = NULL; 341 type->ks_limit = 0; 342 } 343 344 /* 345 * Increase the kmalloc pool limit for the specified pool. No changes 346 * are the made if the pool would shrink. 347 */ 348 void 349 kmalloc_raise_limit(struct malloc_type *type, size_t bytes) 350 { 351 if (type->ks_limit == 0) 352 malloc_init(type); 353 if (bytes == 0) 354 bytes = KvaSize; 355 if (type->ks_limit < bytes) 356 type->ks_limit = bytes; 357 } 358 359 /* 360 * Dynamically create a malloc pool. This function is a NOP if *typep is 361 * already non-NULL. 362 */ 363 void 364 kmalloc_create(struct malloc_type **typep, const char *descr) 365 { 366 struct malloc_type *type; 367 368 if (*typep == NULL) { 369 type = kmalloc(sizeof(*type), M_TEMP, M_WAITOK | M_ZERO); 370 type->ks_magic = M_MAGIC; 371 type->ks_shortdesc = descr; 372 malloc_init(type); 373 *typep = type; 374 } 375 } 376 377 /* 378 * Destroy a dynamically created malloc pool. This function is a NOP if 379 * the pool has already been destroyed. 380 */ 381 void 382 kmalloc_destroy(struct malloc_type **typep) 383 { 384 if (*typep != NULL) { 385 malloc_uninit(*typep); 386 kfree(*typep, M_TEMP); 387 *typep = NULL; 388 } 389 } 390 391 /* 392 * Calculate the zone index for the allocation request size and set the 393 * allocation request size to that particular zone's chunk size. 394 */ 395 static __inline int 396 zoneindex(unsigned long *bytes) 397 { 398 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */ 399 if (n < 128) { 400 *bytes = n = (n + 7) & ~7; 401 return(n / 8 - 1); /* 8 byte chunks, 16 zones */ 402 } 403 if (n < 256) { 404 *bytes = n = (n + 15) & ~15; 405 return(n / 16 + 7); 406 } 407 if (n < 8192) { 408 if (n < 512) { 409 *bytes = n = (n + 31) & ~31; 410 return(n / 32 + 15); 411 } 412 if (n < 1024) { 413 *bytes = n = (n + 63) & ~63; 414 return(n / 64 + 23); 415 } 416 if (n < 2048) { 417 *bytes = n = (n + 127) & ~127; 418 return(n / 128 + 31); 419 } 420 if (n < 4096) { 421 *bytes = n = (n + 255) & ~255; 422 return(n / 256 + 39); 423 } 424 *bytes = n = (n + 511) & ~511; 425 return(n / 512 + 47); 426 } 427 #if ZALLOC_ZONE_LIMIT > 8192 428 if (n < 16384) { 429 *bytes = n = (n + 1023) & ~1023; 430 return(n / 1024 + 55); 431 } 432 #endif 433 #if ZALLOC_ZONE_LIMIT > 16384 434 if (n < 32768) { 435 *bytes = n = (n + 2047) & ~2047; 436 return(n / 2048 + 63); 437 } 438 #endif 439 panic("Unexpected byte count %d", n); 440 return(0); 441 } 442 443 /* 444 * kmalloc() (SLAB ALLOCATOR) 445 * 446 * Allocate memory via the slab allocator. If the request is too large, 447 * or if it page-aligned beyond a certain size, we fall back to the 448 * KMEM subsystem. A SLAB tracking descriptor must be specified, use 449 * &SlabMisc if you don't care. 450 * 451 * M_RNOWAIT - don't block. 452 * M_NULLOK - return NULL instead of blocking. 453 * M_ZERO - zero the returned memory. 454 * M_USE_RESERVE - allow greater drawdown of the free list 455 * M_USE_INTERRUPT_RESERVE - allow the freelist to be exhausted 456 * 457 * MPSAFE 458 */ 459 void * 460 kmalloc(unsigned long size, struct malloc_type *type, int flags) 461 { 462 SLZone *z; 463 SLChunk *chunk; 464 #ifdef SMP 465 SLChunk *bchunk; 466 #endif 467 SLGlobalData *slgd; 468 struct globaldata *gd; 469 int zi; 470 #ifdef INVARIANTS 471 int i; 472 #endif 473 474 logmemory_quick(malloc_beg); 475 gd = mycpu; 476 slgd = &gd->gd_slab; 477 478 /* 479 * XXX silly to have this in the critical path. 480 */ 481 if (type->ks_limit == 0) { 482 crit_enter(); 483 if (type->ks_limit == 0) 484 malloc_init(type); 485 crit_exit(); 486 } 487 ++type->ks_calls; 488 489 /* 490 * Handle the case where the limit is reached. Panic if we can't return 491 * NULL. The original malloc code looped, but this tended to 492 * simply deadlock the computer. 493 * 494 * ks_loosememuse is an up-only limit that is NOT MP-synchronized, used 495 * to determine if a more complete limit check should be done. The 496 * actual memory use is tracked via ks_memuse[cpu]. 497 */ 498 while (type->ks_loosememuse >= type->ks_limit) { 499 int i; 500 long ttl; 501 502 for (i = ttl = 0; i < ncpus; ++i) 503 ttl += type->ks_memuse[i]; 504 type->ks_loosememuse = ttl; /* not MP synchronized */ 505 if ((ssize_t)ttl < 0) /* deal with occassional race */ 506 ttl = 0; 507 if (ttl >= type->ks_limit) { 508 if (flags & M_NULLOK) { 509 logmemory(malloc_end, NULL, type, size, flags); 510 return(NULL); 511 } 512 panic("%s: malloc limit exceeded", type->ks_shortdesc); 513 } 514 } 515 516 /* 517 * Handle the degenerate size == 0 case. Yes, this does happen. 518 * Return a special pointer. This is to maintain compatibility with 519 * the original malloc implementation. Certain devices, such as the 520 * adaptec driver, not only allocate 0 bytes, they check for NULL and 521 * also realloc() later on. Joy. 522 */ 523 if (size == 0) { 524 logmemory(malloc_end, ZERO_LENGTH_PTR, type, size, flags); 525 return(ZERO_LENGTH_PTR); 526 } 527 528 /* 529 * Handle hysteresis from prior frees here in malloc(). We cannot 530 * safely manipulate the kernel_map in free() due to free() possibly 531 * being called via an IPI message or from sensitive interrupt code. 532 * 533 * NOTE: ku_pagecnt must be cleared before we free the slab or we 534 * might race another cpu allocating the kva and setting 535 * ku_pagecnt. 536 */ 537 while (slgd->NFreeZones > ZONE_RELS_THRESH && (flags & M_RNOWAIT) == 0) { 538 crit_enter(); 539 if (slgd->NFreeZones > ZONE_RELS_THRESH) { /* crit sect race */ 540 struct kmemusage *kup; 541 542 z = slgd->FreeZones; 543 slgd->FreeZones = z->z_Next; 544 --slgd->NFreeZones; 545 kup = btokup(z); 546 kup->ku_pagecnt = 0; 547 kmem_slab_free(z, ZoneSize); /* may block */ 548 atomic_add_int(&ZoneGenAlloc, -(int)ZoneSize / 1024); 549 } 550 crit_exit(); 551 } 552 553 /* 554 * XXX handle oversized frees that were queued from kfree(). 555 */ 556 while (slgd->FreeOvZones && (flags & M_RNOWAIT) == 0) { 557 crit_enter(); 558 if ((z = slgd->FreeOvZones) != NULL) { 559 vm_size_t tsize; 560 561 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC); 562 slgd->FreeOvZones = z->z_Next; 563 tsize = z->z_ChunkSize; 564 kmem_slab_free(z, tsize); /* may block */ 565 atomic_add_int(&ZoneBigAlloc, -(int)tsize / 1024); 566 } 567 crit_exit(); 568 } 569 570 /* 571 * Handle large allocations directly. There should not be very many of 572 * these so performance is not a big issue. 573 * 574 * The backend allocator is pretty nasty on a SMP system. Use the 575 * slab allocator for one and two page-sized chunks even though we lose 576 * some efficiency. XXX maybe fix mmio and the elf loader instead. 577 */ 578 if (size >= ZoneLimit || ((size & PAGE_MASK) == 0 && size > PAGE_SIZE*2)) { 579 struct kmemusage *kup; 580 581 size = round_page(size); 582 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags); 583 if (chunk == NULL) { 584 logmemory(malloc_end, NULL, type, size, flags); 585 return(NULL); 586 } 587 atomic_add_int(&ZoneBigAlloc, (int)size / 1024); 588 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */ 589 flags |= M_PASSIVE_ZERO; 590 kup = btokup(chunk); 591 kup->ku_pagecnt = size / PAGE_SIZE; 592 crit_enter(); 593 goto done; 594 } 595 596 /* 597 * Attempt to allocate out of an existing zone. First try the free list, 598 * then allocate out of unallocated space. If we find a good zone move 599 * it to the head of the list so later allocations find it quickly 600 * (we might have thousands of zones in the list). 601 * 602 * Note: zoneindex() will panic of size is too large. 603 */ 604 zi = zoneindex(&size); 605 KKASSERT(zi < NZONES); 606 crit_enter(); 607 608 if ((z = slgd->ZoneAry[zi]) != NULL) { 609 /* 610 * Locate a chunk - we have to have at least one. If this is the 611 * last chunk go ahead and do the work to retrieve chunks freed 612 * from remote cpus, and if the zone is still empty move it off 613 * the ZoneAry. 614 */ 615 if (--z->z_NFree <= 0) { 616 KKASSERT(z->z_NFree == 0); 617 618 #ifdef SMP 619 /* 620 * WARNING! This code competes with other cpus. It is ok 621 * for us to not drain RChunks here but we might as well, and 622 * it is ok if more accumulate after we're done. 623 * 624 * Set RSignal before pulling rchunks off, indicating that we 625 * will be moving ourselves off of the ZoneAry. Remote ends will 626 * read RSignal before putting rchunks on thus interlocking 627 * their IPI signaling. 628 */ 629 if (z->z_RChunks == NULL) 630 atomic_swap_int(&z->z_RSignal, 1); 631 632 while ((bchunk = z->z_RChunks) != NULL) { 633 cpu_ccfence(); 634 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) { 635 *z->z_LChunksp = bchunk; 636 while (bchunk) { 637 chunk_mark_free(z, bchunk); 638 z->z_LChunksp = &bchunk->c_Next; 639 bchunk = bchunk->c_Next; 640 ++z->z_NFree; 641 } 642 break; 643 } 644 } 645 #endif 646 /* 647 * Remove from the zone list if no free chunks remain. 648 * Clear RSignal 649 */ 650 if (z->z_NFree == 0) { 651 slgd->ZoneAry[zi] = z->z_Next; 652 z->z_Next = NULL; 653 } else { 654 z->z_RSignal = 0; 655 } 656 } 657 658 /* 659 * Fast path, we have chunks available in z_LChunks. 660 */ 661 chunk = z->z_LChunks; 662 if (chunk) { 663 chunk_mark_allocated(z, chunk); 664 z->z_LChunks = chunk->c_Next; 665 if (z->z_LChunks == NULL) 666 z->z_LChunksp = &z->z_LChunks; 667 goto done; 668 } 669 670 /* 671 * No chunks are available in LChunks, the free chunk MUST be 672 * in the never-before-used memory area, controlled by UIndex. 673 * 674 * The consequences are very serious if our zone got corrupted so 675 * we use an explicit panic rather than a KASSERT. 676 */ 677 if (z->z_UIndex + 1 != z->z_NMax) 678 ++z->z_UIndex; 679 else 680 z->z_UIndex = 0; 681 682 if (z->z_UIndex == z->z_UEndIndex) 683 panic("slaballoc: corrupted zone"); 684 685 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 686 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 687 flags &= ~M_ZERO; 688 flags |= M_PASSIVE_ZERO; 689 } 690 chunk_mark_allocated(z, chunk); 691 goto done; 692 } 693 694 /* 695 * If all zones are exhausted we need to allocate a new zone for this 696 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see 697 * UAlloc use above in regards to M_ZERO. Note that when we are reusing 698 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and 699 * we do not pre-zero it because we do not want to mess up the L1 cache. 700 * 701 * At least one subsystem, the tty code (see CROUND) expects power-of-2 702 * allocations to be power-of-2 aligned. We maintain compatibility by 703 * adjusting the base offset below. 704 */ 705 { 706 int off; 707 struct kmemusage *kup; 708 709 if ((z = slgd->FreeZones) != NULL) { 710 slgd->FreeZones = z->z_Next; 711 --slgd->NFreeZones; 712 bzero(z, sizeof(SLZone)); 713 z->z_Flags |= SLZF_UNOTZEROD; 714 } else { 715 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO); 716 if (z == NULL) 717 goto fail; 718 atomic_add_int(&ZoneGenAlloc, (int)ZoneSize / 1024); 719 } 720 721 /* 722 * How big is the base structure? 723 */ 724 #if defined(INVARIANTS) 725 /* 726 * Make room for z_Bitmap. An exact calculation is somewhat more 727 * complicated so don't make an exact calculation. 728 */ 729 off = offsetof(SLZone, z_Bitmap[(ZoneSize / size + 31) / 32]); 730 bzero(z->z_Bitmap, (ZoneSize / size + 31) / 8); 731 #else 732 off = sizeof(SLZone); 733 #endif 734 735 /* 736 * Guarentee power-of-2 alignment for power-of-2-sized chunks. 737 * Otherwise just 8-byte align the data. 738 */ 739 if ((size | (size - 1)) + 1 == (size << 1)) 740 off = (off + size - 1) & ~(size - 1); 741 else 742 off = (off + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK; 743 z->z_Magic = ZALLOC_SLAB_MAGIC; 744 z->z_ZoneIndex = zi; 745 z->z_NMax = (ZoneSize - off) / size; 746 z->z_NFree = z->z_NMax - 1; 747 z->z_BasePtr = (char *)z + off; 748 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax; 749 z->z_ChunkSize = size; 750 z->z_CpuGd = gd; 751 z->z_Cpu = gd->gd_cpuid; 752 z->z_LChunksp = &z->z_LChunks; 753 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 754 z->z_Next = slgd->ZoneAry[zi]; 755 slgd->ZoneAry[zi] = z; 756 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 757 flags &= ~M_ZERO; /* already zero'd */ 758 flags |= M_PASSIVE_ZERO; 759 } 760 kup = btokup(z); 761 kup->ku_pagecnt = -(z->z_Cpu + 1); /* -1 to -(N+1) */ 762 chunk_mark_allocated(z, chunk); 763 764 /* 765 * Slide the base index for initial allocations out of the next 766 * zone we create so we do not over-weight the lower part of the 767 * cpu memory caches. 768 */ 769 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE) 770 & (ZALLOC_MAX_ZONE_SIZE - 1); 771 } 772 773 done: 774 ++type->ks_inuse[gd->gd_cpuid]; 775 type->ks_memuse[gd->gd_cpuid] += size; 776 type->ks_loosememuse += size; /* not MP synchronized */ 777 crit_exit(); 778 779 if (flags & M_ZERO) 780 bzero(chunk, size); 781 #ifdef INVARIANTS 782 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0) { 783 if (use_malloc_pattern) { 784 for (i = 0; i < size; i += sizeof(int)) { 785 *(int *)((char *)chunk + i) = -1; 786 } 787 } 788 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */ 789 } 790 #endif 791 logmemory(malloc_end, chunk, type, size, flags); 792 return(chunk); 793 fail: 794 crit_exit(); 795 logmemory(malloc_end, NULL, type, size, flags); 796 return(NULL); 797 } 798 799 /* 800 * kernel realloc. (SLAB ALLOCATOR) (MP SAFE) 801 * 802 * Generally speaking this routine is not called very often and we do 803 * not attempt to optimize it beyond reusing the same pointer if the 804 * new size fits within the chunking of the old pointer's zone. 805 */ 806 void * 807 krealloc(void *ptr, unsigned long size, struct malloc_type *type, int flags) 808 { 809 struct kmemusage *kup; 810 SLZone *z; 811 void *nptr; 812 unsigned long osize; 813 814 KKASSERT((flags & M_ZERO) == 0); /* not supported */ 815 816 if (ptr == NULL || ptr == ZERO_LENGTH_PTR) 817 return(kmalloc(size, type, flags)); 818 if (size == 0) { 819 kfree(ptr, type); 820 return(NULL); 821 } 822 823 /* 824 * Handle oversized allocations. XXX we really should require that a 825 * size be passed to free() instead of this nonsense. 826 */ 827 kup = btokup(ptr); 828 if (kup->ku_pagecnt > 0) { 829 osize = kup->ku_pagecnt << PAGE_SHIFT; 830 if (osize == round_page(size)) 831 return(ptr); 832 if ((nptr = kmalloc(size, type, flags)) == NULL) 833 return(NULL); 834 bcopy(ptr, nptr, min(size, osize)); 835 kfree(ptr, type); 836 return(nptr); 837 } 838 839 /* 840 * Get the original allocation's zone. If the new request winds up 841 * using the same chunk size we do not have to do anything. 842 */ 843 z = (SLZone *)((uintptr_t)ptr & ZoneMask); 844 kup = btokup(z); 845 KKASSERT(kup->ku_pagecnt < 0); 846 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 847 848 /* 849 * Allocate memory for the new request size. Note that zoneindex has 850 * already adjusted the request size to the appropriate chunk size, which 851 * should optimize our bcopy(). Then copy and return the new pointer. 852 * 853 * Resizing a non-power-of-2 allocation to a power-of-2 size does not 854 * necessary align the result. 855 * 856 * We can only zoneindex (to align size to the chunk size) if the new 857 * size is not too large. 858 */ 859 if (size < ZoneLimit) { 860 zoneindex(&size); 861 if (z->z_ChunkSize == size) 862 return(ptr); 863 } 864 if ((nptr = kmalloc(size, type, flags)) == NULL) 865 return(NULL); 866 bcopy(ptr, nptr, min(size, z->z_ChunkSize)); 867 kfree(ptr, type); 868 return(nptr); 869 } 870 871 /* 872 * Return the kmalloc limit for this type, in bytes. 873 */ 874 long 875 kmalloc_limit(struct malloc_type *type) 876 { 877 if (type->ks_limit == 0) { 878 crit_enter(); 879 if (type->ks_limit == 0) 880 malloc_init(type); 881 crit_exit(); 882 } 883 return(type->ks_limit); 884 } 885 886 /* 887 * Allocate a copy of the specified string. 888 * 889 * (MP SAFE) (MAY BLOCK) 890 */ 891 char * 892 kstrdup(const char *str, struct malloc_type *type) 893 { 894 int zlen; /* length inclusive of terminating NUL */ 895 char *nstr; 896 897 if (str == NULL) 898 return(NULL); 899 zlen = strlen(str) + 1; 900 nstr = kmalloc(zlen, type, M_WAITOK); 901 bcopy(str, nstr, zlen); 902 return(nstr); 903 } 904 905 #ifdef SMP 906 /* 907 * Notify our cpu that a remote cpu has freed some chunks in a zone that 908 * we own. Due to MP races we might no longer own the zone, use the 909 * kmemusage array to check. 910 */ 911 static 912 void 913 kfree_remote(void *ptr) 914 { 915 struct kmemusage *kup; 916 SLGlobalData *slgd; 917 SLChunk *bchunk; 918 SLZone *z; 919 int nfree; 920 921 /* 922 * Do not dereference (z) until we validate that its storage is 923 * still around. 924 */ 925 slgd = &mycpu->gd_slab; 926 z = ptr; 927 kup = btokup(z); 928 929 if (kup->ku_pagecnt == -((int)mycpuid + 1)) { /* -1 to -(N+1) */ 930 logmemory(free_rem_beg, z, NULL, 0, 0); 931 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 932 KKASSERT(z->z_Cpu == mycpu->gd_cpuid); 933 nfree = z->z_NFree; 934 935 /* 936 * Indicate that we will no longer be off of the ZoneAry by 937 * clearing RSignal. 938 */ 939 if (z->z_RChunks) 940 z->z_RSignal = 0; 941 942 /* 943 * Atomically extract the bchunks list and then process it back 944 * into the lchunks list. We want to append our bchunks to the 945 * lchunks list and not prepend since we likely do not have 946 * cache mastership of the related data (not that it helps since 947 * we are using c_Next). 948 */ 949 while ((bchunk = z->z_RChunks) != NULL) { 950 cpu_ccfence(); 951 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) { 952 *z->z_LChunksp = bchunk; 953 while (bchunk) { 954 chunk_mark_free(z, bchunk); 955 z->z_LChunksp = &bchunk->c_Next; 956 bchunk = bchunk->c_Next; 957 ++z->z_NFree; 958 } 959 break; 960 } 961 } 962 if (z->z_NFree && nfree == 0) { 963 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 964 slgd->ZoneAry[z->z_ZoneIndex] = z; 965 } 966 967 /* 968 * If the zone becomes totally free, and there are other zones we 969 * can allocate from, move this zone to the FreeZones list. Since 970 * this code can be called from an IPI callback, do *NOT* try to mess 971 * with kernel_map here. Hysteresis will be performed at malloc() time. 972 */ 973 if (z->z_NFree == z->z_NMax && 974 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) 975 ) { 976 struct kmemusage *kup; 977 SLZone **pz; 978 979 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; 980 z != *pz; 981 pz = &(*pz)->z_Next) { 982 ; 983 } 984 *pz = z->z_Next; 985 z->z_Magic = -1; 986 z->z_Next = slgd->FreeZones; 987 slgd->FreeZones = z; 988 ++slgd->NFreeZones; 989 kup = btokup(z); 990 kup->ku_pagecnt = 0; 991 } 992 logmemory(free_rem_end, z, bchunk, 0, 0); 993 } 994 } 995 996 #endif 997 998 /* 999 * free (SLAB ALLOCATOR) 1000 * 1001 * Free a memory block previously allocated by malloc. Note that we do not 1002 * attempt to update ks_loosememuse as MP races could prevent us from 1003 * checking memory limits in malloc. 1004 * 1005 * MPSAFE 1006 */ 1007 void 1008 kfree(void *ptr, struct malloc_type *type) 1009 { 1010 SLZone *z; 1011 SLChunk *chunk; 1012 SLGlobalData *slgd; 1013 struct globaldata *gd; 1014 struct kmemusage *kup; 1015 unsigned long size; 1016 #ifdef SMP 1017 SLChunk *bchunk; 1018 int rsignal; 1019 #endif 1020 1021 logmemory_quick(free_beg); 1022 gd = mycpu; 1023 slgd = &gd->gd_slab; 1024 1025 if (ptr == NULL) 1026 panic("trying to free NULL pointer"); 1027 1028 /* 1029 * Handle special 0-byte allocations 1030 */ 1031 if (ptr == ZERO_LENGTH_PTR) { 1032 logmemory(free_zero, ptr, type, -1, 0); 1033 logmemory_quick(free_end); 1034 return; 1035 } 1036 1037 /* 1038 * Panic on bad malloc type 1039 */ 1040 if (type->ks_magic != M_MAGIC) 1041 panic("free: malloc type lacks magic"); 1042 1043 /* 1044 * Handle oversized allocations. XXX we really should require that a 1045 * size be passed to free() instead of this nonsense. 1046 * 1047 * This code is never called via an ipi. 1048 */ 1049 kup = btokup(ptr); 1050 if (kup->ku_pagecnt > 0) { 1051 size = kup->ku_pagecnt << PAGE_SHIFT; 1052 kup->ku_pagecnt = 0; 1053 #ifdef INVARIANTS 1054 KKASSERT(sizeof(weirdary) <= size); 1055 bcopy(weirdary, ptr, sizeof(weirdary)); 1056 #endif 1057 /* 1058 * NOTE: For oversized allocations we do not record the 1059 * originating cpu. It gets freed on the cpu calling 1060 * kfree(). The statistics are in aggregate. 1061 * 1062 * note: XXX we have still inherited the interrupts-can't-block 1063 * assumption. An interrupt thread does not bump 1064 * gd_intr_nesting_level so check TDF_INTTHREAD. This is 1065 * primarily until we can fix softupdate's assumptions about free(). 1066 */ 1067 crit_enter(); 1068 --type->ks_inuse[gd->gd_cpuid]; 1069 type->ks_memuse[gd->gd_cpuid] -= size; 1070 if (mycpu->gd_intr_nesting_level || 1071 (gd->gd_curthread->td_flags & TDF_INTTHREAD)) 1072 { 1073 logmemory(free_ovsz_delayed, ptr, type, size, 0); 1074 z = (SLZone *)ptr; 1075 z->z_Magic = ZALLOC_OVSZ_MAGIC; 1076 z->z_Next = slgd->FreeOvZones; 1077 z->z_ChunkSize = size; 1078 slgd->FreeOvZones = z; 1079 crit_exit(); 1080 } else { 1081 crit_exit(); 1082 logmemory(free_ovsz, ptr, type, size, 0); 1083 kmem_slab_free(ptr, size); /* may block */ 1084 atomic_add_int(&ZoneBigAlloc, -(int)size / 1024); 1085 } 1086 logmemory_quick(free_end); 1087 return; 1088 } 1089 1090 /* 1091 * Zone case. Figure out the zone based on the fact that it is 1092 * ZoneSize aligned. 1093 */ 1094 z = (SLZone *)((uintptr_t)ptr & ZoneMask); 1095 kup = btokup(z); 1096 KKASSERT(kup->ku_pagecnt < 0); 1097 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 1098 1099 /* 1100 * If we do not own the zone then use atomic ops to free to the 1101 * remote cpu linked list and notify the target zone using a 1102 * passive message. 1103 * 1104 * The target zone cannot be deallocated while we own a chunk of it, 1105 * so the zone header's storage is stable until the very moment 1106 * we adjust z_RChunks. After that we cannot safely dereference (z). 1107 * 1108 * (no critical section needed) 1109 */ 1110 if (z->z_CpuGd != gd) { 1111 #ifdef SMP 1112 /* 1113 * Making these adjustments now allow us to avoid passing (type) 1114 * to the remote cpu. Note that ks_inuse/ks_memuse is being 1115 * adjusted on OUR cpu, not the zone cpu, but it should all still 1116 * sum up properly and cancel out. 1117 */ 1118 crit_enter(); 1119 --type->ks_inuse[gd->gd_cpuid]; 1120 type->ks_memuse[gd->gd_cpuid] -= z->z_ChunkSize; 1121 crit_exit(); 1122 1123 /* 1124 * WARNING! This code competes with other cpus. Once we 1125 * successfully link the chunk to RChunks the remote 1126 * cpu can rip z's storage out from under us. 1127 */ 1128 rsignal = z->z_RSignal; 1129 cpu_lfence(); 1130 1131 chunk = ptr; 1132 for (;;) { 1133 bchunk = z->z_RChunks; 1134 cpu_ccfence(); 1135 chunk->c_Next = bchunk; 1136 cpu_sfence(); 1137 1138 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, chunk)) 1139 break; 1140 } 1141 /* z cannot be dereferenced now */ 1142 1143 /* 1144 * We have to signal the remote cpu if our actions will cause 1145 * the remote zone to be placed back on ZoneAry so it can 1146 * move the zone back on. 1147 * 1148 * We only need to deal with NULL->non-NULL RChunk transitions 1149 * and only if z_RSignal is set. We interlock by reading rsignal 1150 * before adding our chunk to RChunks. This should result in 1151 * virtually no IPI traffic. 1152 * 1153 * We can use a passive IPI to reduce overhead even further. 1154 */ 1155 if (bchunk == NULL && rsignal) { 1156 logmemory(free_request, ptr, type, z->z_ChunkSize, 0); 1157 lwkt_send_ipiq_passive(z->z_CpuGd, kfree_remote, z); 1158 } 1159 #else 1160 panic("Corrupt SLZone"); 1161 #endif 1162 logmemory_quick(free_end); 1163 return; 1164 } 1165 1166 /* 1167 * kfree locally 1168 */ 1169 logmemory(free_chunk, ptr, type, z->z_ChunkSize, 0); 1170 1171 crit_enter(); 1172 chunk = ptr; 1173 chunk_mark_free(z, chunk); 1174 1175 /* 1176 * Put weird data into the memory to detect modifications after freeing, 1177 * illegal pointer use after freeing (we should fault on the odd address), 1178 * and so forth. XXX needs more work, see the old malloc code. 1179 */ 1180 #ifdef INVARIANTS 1181 if (z->z_ChunkSize < sizeof(weirdary)) 1182 bcopy(weirdary, chunk, z->z_ChunkSize); 1183 else 1184 bcopy(weirdary, chunk, sizeof(weirdary)); 1185 #endif 1186 1187 /* 1188 * Add this free non-zero'd chunk to a linked list for reuse. Add 1189 * to the front of the linked list so it is more likely to be 1190 * reallocated, since it is already in our L1 cache. 1191 */ 1192 #ifdef INVARIANTS 1193 if ((vm_offset_t)chunk < KvaStart || (vm_offset_t)chunk >= KvaEnd) 1194 panic("BADFREE %p", chunk); 1195 #endif 1196 chunk->c_Next = z->z_LChunks; 1197 z->z_LChunks = chunk; 1198 if (chunk->c_Next == NULL) 1199 z->z_LChunksp = &chunk->c_Next; 1200 1201 #ifdef INVARIANTS 1202 if (chunk->c_Next && (vm_offset_t)chunk->c_Next < KvaStart) 1203 panic("BADFREE2"); 1204 #endif 1205 1206 /* 1207 * Bump the number of free chunks. If it becomes non-zero the zone 1208 * must be added back onto the appropriate list. 1209 */ 1210 if (z->z_NFree++ == 0) { 1211 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 1212 slgd->ZoneAry[z->z_ZoneIndex] = z; 1213 } 1214 1215 --type->ks_inuse[z->z_Cpu]; 1216 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize; 1217 1218 /* 1219 * If the zone becomes totally free, and there are other zones we 1220 * can allocate from, move this zone to the FreeZones list. Since 1221 * this code can be called from an IPI callback, do *NOT* try to mess 1222 * with kernel_map here. Hysteresis will be performed at malloc() time. 1223 */ 1224 if (z->z_NFree == z->z_NMax && 1225 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) 1226 ) { 1227 SLZone **pz; 1228 struct kmemusage *kup; 1229 1230 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next) 1231 ; 1232 *pz = z->z_Next; 1233 z->z_Magic = -1; 1234 z->z_Next = slgd->FreeZones; 1235 slgd->FreeZones = z; 1236 ++slgd->NFreeZones; 1237 kup = btokup(z); 1238 kup->ku_pagecnt = 0; 1239 } 1240 logmemory_quick(free_end); 1241 crit_exit(); 1242 } 1243 1244 #if defined(INVARIANTS) 1245 1246 /* 1247 * Helper routines for sanity checks 1248 */ 1249 static 1250 void 1251 chunk_mark_allocated(SLZone *z, void *chunk) 1252 { 1253 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize; 1254 __uint32_t *bitptr; 1255 1256 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0); 1257 KASSERT(bitdex >= 0 && bitdex < z->z_NMax, 1258 ("memory chunk %p bit index %d is illegal", chunk, bitdex)); 1259 bitptr = &z->z_Bitmap[bitdex >> 5]; 1260 bitdex &= 31; 1261 KASSERT((*bitptr & (1 << bitdex)) == 0, 1262 ("memory chunk %p is already allocated!", chunk)); 1263 *bitptr |= 1 << bitdex; 1264 } 1265 1266 static 1267 void 1268 chunk_mark_free(SLZone *z, void *chunk) 1269 { 1270 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize; 1271 __uint32_t *bitptr; 1272 1273 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0); 1274 KASSERT(bitdex >= 0 && bitdex < z->z_NMax, 1275 ("memory chunk %p bit index %d is illegal!", chunk, bitdex)); 1276 bitptr = &z->z_Bitmap[bitdex >> 5]; 1277 bitdex &= 31; 1278 KASSERT((*bitptr & (1 << bitdex)) != 0, 1279 ("memory chunk %p is already free!", chunk)); 1280 *bitptr &= ~(1 << bitdex); 1281 } 1282 1283 #endif 1284 1285 /* 1286 * kmem_slab_alloc() 1287 * 1288 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the 1289 * specified alignment. M_* flags are expected in the flags field. 1290 * 1291 * Alignment must be a multiple of PAGE_SIZE. 1292 * 1293 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(), 1294 * but when we move zalloc() over to use this function as its backend 1295 * we will have to switch to kreserve/krelease and call reserve(0) 1296 * after the new space is made available. 1297 * 1298 * Interrupt code which has preempted other code is not allowed to 1299 * use PQ_CACHE pages. However, if an interrupt thread is run 1300 * non-preemptively or blocks and then runs non-preemptively, then 1301 * it is free to use PQ_CACHE pages. 1302 */ 1303 static void * 1304 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags) 1305 { 1306 vm_size_t i; 1307 vm_offset_t addr; 1308 int count, vmflags, base_vmflags; 1309 thread_t td; 1310 1311 size = round_page(size); 1312 addr = vm_map_min(&kernel_map); 1313 1314 /* 1315 * Reserve properly aligned space from kernel_map. RNOWAIT allocations 1316 * cannot block. 1317 */ 1318 if (flags & M_RNOWAIT) { 1319 if (lwkt_trytoken(&vm_token) == 0) 1320 return(NULL); 1321 } else { 1322 lwkt_gettoken(&vm_token); 1323 } 1324 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1325 crit_enter(); 1326 vm_map_lock(&kernel_map); 1327 if (vm_map_findspace(&kernel_map, addr, size, align, 0, &addr)) { 1328 vm_map_unlock(&kernel_map); 1329 if ((flags & M_NULLOK) == 0) 1330 panic("kmem_slab_alloc(): kernel_map ran out of space!"); 1331 vm_map_entry_release(count); 1332 crit_exit(); 1333 lwkt_reltoken(&vm_token); 1334 return(NULL); 1335 } 1336 1337 /* 1338 * kernel_object maps 1:1 to kernel_map. 1339 */ 1340 vm_object_reference(&kernel_object); 1341 vm_map_insert(&kernel_map, &count, 1342 &kernel_object, addr, addr, addr + size, 1343 VM_MAPTYPE_NORMAL, 1344 VM_PROT_ALL, VM_PROT_ALL, 1345 0); 1346 1347 td = curthread; 1348 1349 base_vmflags = 0; 1350 if (flags & M_ZERO) 1351 base_vmflags |= VM_ALLOC_ZERO; 1352 if (flags & M_USE_RESERVE) 1353 base_vmflags |= VM_ALLOC_SYSTEM; 1354 if (flags & M_USE_INTERRUPT_RESERVE) 1355 base_vmflags |= VM_ALLOC_INTERRUPT; 1356 if ((flags & (M_RNOWAIT|M_WAITOK)) == 0) { 1357 panic("kmem_slab_alloc: bad flags %08x (%p)", 1358 flags, ((int **)&size)[-1]); 1359 } 1360 1361 1362 /* 1363 * Allocate the pages. Do not mess with the PG_ZERO flag yet. 1364 */ 1365 for (i = 0; i < size; i += PAGE_SIZE) { 1366 vm_page_t m; 1367 1368 /* 1369 * VM_ALLOC_NORMAL can only be set if we are not preempting. 1370 * 1371 * VM_ALLOC_SYSTEM is automatically set if we are preempting and 1372 * M_WAITOK was specified as an alternative (i.e. M_USE_RESERVE is 1373 * implied in this case), though I'm not sure if we really need to 1374 * do that. 1375 */ 1376 vmflags = base_vmflags; 1377 if (flags & M_WAITOK) { 1378 if (td->td_preempted) 1379 vmflags |= VM_ALLOC_SYSTEM; 1380 else 1381 vmflags |= VM_ALLOC_NORMAL; 1382 } 1383 1384 m = vm_page_alloc(&kernel_object, OFF_TO_IDX(addr + i), vmflags); 1385 1386 /* 1387 * If the allocation failed we either return NULL or we retry. 1388 * 1389 * If M_WAITOK is specified we wait for more memory and retry. 1390 * If M_WAITOK is specified from a preemption we yield instead of 1391 * wait. Livelock will not occur because the interrupt thread 1392 * will not be preempting anyone the second time around after the 1393 * yield. 1394 */ 1395 if (m == NULL) { 1396 if (flags & M_WAITOK) { 1397 if (td->td_preempted) { 1398 vm_map_unlock(&kernel_map); 1399 lwkt_switch(); 1400 vm_map_lock(&kernel_map); 1401 } else { 1402 vm_map_unlock(&kernel_map); 1403 vm_wait(0); 1404 vm_map_lock(&kernel_map); 1405 } 1406 i -= PAGE_SIZE; /* retry */ 1407 continue; 1408 } 1409 1410 /* 1411 * We were unable to recover, cleanup and return NULL 1412 * 1413 * (vm_token already held) 1414 */ 1415 while (i != 0) { 1416 i -= PAGE_SIZE; 1417 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i)); 1418 /* page should already be busy */ 1419 vm_page_free(m); 1420 } 1421 vm_map_delete(&kernel_map, addr, addr + size, &count); 1422 vm_map_unlock(&kernel_map); 1423 vm_map_entry_release(count); 1424 crit_exit(); 1425 lwkt_reltoken(&vm_token); 1426 return(NULL); 1427 } 1428 } 1429 1430 /* 1431 * Success! 1432 * 1433 * Mark the map entry as non-pageable using a routine that allows us to 1434 * populate the underlying pages. 1435 * 1436 * The pages were busied by the allocations above. 1437 */ 1438 vm_map_set_wired_quick(&kernel_map, addr, size, &count); 1439 crit_exit(); 1440 1441 /* 1442 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO. 1443 */ 1444 lwkt_gettoken(&vm_token); 1445 for (i = 0; i < size; i += PAGE_SIZE) { 1446 vm_page_t m; 1447 1448 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i)); 1449 m->valid = VM_PAGE_BITS_ALL; 1450 /* page should already be busy */ 1451 vm_page_wire(m); 1452 vm_page_wakeup(m); 1453 pmap_enter(&kernel_pmap, addr + i, m, VM_PROT_ALL, 1); 1454 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO)) 1455 bzero((char *)addr + i, PAGE_SIZE); 1456 vm_page_flag_clear(m, PG_ZERO); 1457 KKASSERT(m->flags & (PG_WRITEABLE | PG_MAPPED)); 1458 vm_page_flag_set(m, PG_REFERENCED); 1459 } 1460 lwkt_reltoken(&vm_token); 1461 vm_map_unlock(&kernel_map); 1462 vm_map_entry_release(count); 1463 lwkt_reltoken(&vm_token); 1464 return((void *)addr); 1465 } 1466 1467 /* 1468 * kmem_slab_free() 1469 */ 1470 static void 1471 kmem_slab_free(void *ptr, vm_size_t size) 1472 { 1473 crit_enter(); 1474 lwkt_gettoken(&vm_token); 1475 vm_map_remove(&kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size); 1476 lwkt_reltoken(&vm_token); 1477 crit_exit(); 1478 } 1479 1480