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 * This module implements a slab allocator drop-in replacement for the 39 * kernel malloc(). 40 * 41 * A slab allocator reserves a ZONE for each chunk size, then lays the 42 * chunks out in an array within the zone. Allocation and deallocation 43 * is nearly instantanious, and fragmentation/overhead losses are limited 44 * to a fixed worst-case amount. 45 * 46 * The downside of this slab implementation is in the chunk size 47 * multiplied by the number of zones. ~80 zones * 128K = 10MB of VM per cpu. 48 * In a kernel implementation all this memory will be physical so 49 * the zone size is adjusted downward on machines with less physical 50 * memory. The upside is that overhead is bounded... this is the *worst* 51 * case overhead. 52 * 53 * Slab management is done on a per-cpu basis and no locking or mutexes 54 * are required, only a critical section. When one cpu frees memory 55 * belonging to another cpu's slab manager an asynchronous IPI message 56 * will be queued to execute the operation. In addition, both the 57 * high level slab allocator and the low level zone allocator optimize 58 * M_ZERO requests, and the slab allocator does not have to pre initialize 59 * the linked list of chunks. 60 * 61 * XXX Balancing is needed between cpus. Balance will be handled through 62 * asynchronous IPIs primarily by reassigning the z_Cpu ownership of chunks. 63 * 64 * XXX If we have to allocate a new zone and M_USE_RESERVE is set, use of 65 * the new zone should be restricted to M_USE_RESERVE requests only. 66 * 67 * Alloc Size Chunking Number of zones 68 * 0-127 8 16 69 * 128-255 16 8 70 * 256-511 32 8 71 * 512-1023 64 8 72 * 1024-2047 128 8 73 * 2048-4095 256 8 74 * 4096-8191 512 8 75 * 8192-16383 1024 8 76 * 16384-32767 2048 8 77 * (if PAGE_SIZE is 4K the maximum zone allocation is 16383) 78 * 79 * Allocations >= ZoneLimit go directly to kmem. 80 * 81 * API REQUIREMENTS AND SIDE EFFECTS 82 * 83 * To operate as a drop-in replacement to the FreeBSD-4.x malloc() we 84 * have remained compatible with the following API requirements: 85 * 86 * + small power-of-2 sized allocations are power-of-2 aligned (kern_tty) 87 * + all power-of-2 sized allocations are power-of-2 aligned (twe) 88 * + malloc(0) is allowed and returns non-NULL (ahc driver) 89 * + ability to allocate arbitrarily large chunks of memory 90 */ 91 92 #include "opt_vm.h" 93 94 #include <sys/param.h> 95 #include <sys/systm.h> 96 #include <sys/kernel.h> 97 #include <sys/slaballoc.h> 98 #include <sys/mbuf.h> 99 #include <sys/vmmeter.h> 100 #include <sys/lock.h> 101 #include <sys/thread.h> 102 #include <sys/globaldata.h> 103 #include <sys/sysctl.h> 104 #include <sys/ktr.h> 105 106 #include <vm/vm.h> 107 #include <vm/vm_param.h> 108 #include <vm/vm_kern.h> 109 #include <vm/vm_extern.h> 110 #include <vm/vm_object.h> 111 #include <vm/pmap.h> 112 #include <vm/vm_map.h> 113 #include <vm/vm_page.h> 114 #include <vm/vm_pageout.h> 115 116 #include <machine/cpu.h> 117 118 #include <sys/thread2.h> 119 120 #define arysize(ary) (sizeof(ary)/sizeof((ary)[0])) 121 122 #define btokup(z) (&pmap_kvtom((vm_offset_t)(z))->ku_pagecnt) 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 int32_t weirdary[16]; 162 163 static void *kmem_slab_alloc(vm_size_t bytes, vm_offset_t align, int flags); 164 static void kmem_slab_free(void *ptr, vm_size_t bytes); 165 166 #if defined(INVARIANTS) 167 static void chunk_mark_allocated(SLZone *z, void *chunk); 168 static void chunk_mark_free(SLZone *z, void *chunk); 169 #else 170 #define chunk_mark_allocated(z, chunk) 171 #define chunk_mark_free(z, chunk) 172 #endif 173 174 /* 175 * Misc constants. Note that allocations that are exact multiples of 176 * PAGE_SIZE, or exceed the zone limit, fall through to the kmem module. 177 * IN_SAME_PAGE_MASK is used to sanity-check the per-page free lists. 178 */ 179 #define MIN_CHUNK_SIZE 8 /* in bytes */ 180 #define MIN_CHUNK_MASK (MIN_CHUNK_SIZE - 1) 181 #define ZONE_RELS_THRESH 2 /* threshold number of zones */ 182 #define IN_SAME_PAGE_MASK (~(intptr_t)PAGE_MASK | MIN_CHUNK_MASK) 183 184 /* 185 * The WEIRD_ADDR is used as known text to copy into free objects to 186 * try to create deterministic failure cases if the data is accessed after 187 * free. 188 */ 189 #define WEIRD_ADDR 0xdeadc0de 190 #define MAX_COPY sizeof(weirdary) 191 #define ZERO_LENGTH_PTR ((void *)-8) 192 193 /* 194 * Misc global malloc buckets 195 */ 196 197 MALLOC_DEFINE(M_CACHE, "cache", "Various Dynamically allocated caches"); 198 MALLOC_DEFINE(M_DEVBUF, "devbuf", "device driver memory"); 199 MALLOC_DEFINE(M_TEMP, "temp", "misc temporary data buffers"); 200 201 MALLOC_DEFINE(M_IP6OPT, "ip6opt", "IPv6 options"); 202 MALLOC_DEFINE(M_IP6NDP, "ip6ndp", "IPv6 Neighbor Discovery"); 203 204 /* 205 * Initialize the slab memory allocator. We have to choose a zone size based 206 * on available physical memory. We choose a zone side which is approximately 207 * 1/1024th of our memory, so if we have 128MB of ram we have a zone size of 208 * 128K. The zone size is limited to the bounds set in slaballoc.h 209 * (typically 32K min, 128K max). 210 */ 211 static void kmeminit(void *dummy); 212 213 char *ZeroPage; 214 215 SYSINIT(kmem, SI_BOOT1_ALLOCATOR, SI_ORDER_FIRST, kmeminit, NULL) 216 217 #ifdef INVARIANTS 218 /* 219 * If enabled any memory allocated without M_ZERO is initialized to -1. 220 */ 221 static int use_malloc_pattern; 222 SYSCTL_INT(_debug, OID_AUTO, use_malloc_pattern, CTLFLAG_RW, 223 &use_malloc_pattern, 0, 224 "Initialize memory to -1 if M_ZERO not specified"); 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; 236 237 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE; 238 if (limsize > KvaSize) 239 limsize = KvaSize; 240 241 usesize = (int)(limsize / 1024); /* convert to KB */ 242 243 ZoneSize = ZALLOC_MIN_ZONE_SIZE; 244 while (ZoneSize < ZALLOC_MAX_ZONE_SIZE && (ZoneSize << 1) < usesize) 245 ZoneSize <<= 1; 246 ZoneLimit = ZoneSize / 4; 247 if (ZoneLimit > ZALLOC_ZONE_LIMIT) 248 ZoneLimit = ZALLOC_ZONE_LIMIT; 249 ZoneMask = ~(uintptr_t)(ZoneSize - 1); 250 ZonePageCount = ZoneSize / PAGE_SIZE; 251 252 for (i = 0; i < arysize(weirdary); ++i) 253 weirdary[i] = WEIRD_ADDR; 254 255 ZeroPage = kmem_slab_alloc(PAGE_SIZE, PAGE_SIZE, M_WAITOK|M_ZERO); 256 257 if (bootverbose) 258 kprintf("Slab ZoneSize set to %dKB\n", ZoneSize / 1024); 259 } 260 261 /* 262 * Initialize a malloc type tracking structure. 263 */ 264 void 265 malloc_init(void *data) 266 { 267 struct malloc_type *type = data; 268 size_t limsize; 269 270 if (type->ks_magic != M_MAGIC) 271 panic("malloc type lacks magic"); 272 273 if (type->ks_limit != 0) 274 return; 275 276 if (vmstats.v_page_count == 0) 277 panic("malloc_init not allowed before vm init"); 278 279 limsize = (size_t)vmstats.v_page_count * PAGE_SIZE; 280 if (limsize > KvaSize) 281 limsize = KvaSize; 282 type->ks_limit = limsize / 10; 283 284 type->ks_next = kmemstatistics; 285 kmemstatistics = type; 286 } 287 288 void 289 malloc_uninit(void *data) 290 { 291 struct malloc_type *type = data; 292 struct malloc_type *t; 293 #ifdef INVARIANTS 294 int i; 295 long ttl; 296 #endif 297 298 if (type->ks_magic != M_MAGIC) 299 panic("malloc type lacks magic"); 300 301 if (vmstats.v_page_count == 0) 302 panic("malloc_uninit not allowed before vm init"); 303 304 if (type->ks_limit == 0) 305 panic("malloc_uninit on uninitialized type"); 306 307 #ifdef SMP 308 /* Make sure that all pending kfree()s are finished. */ 309 lwkt_synchronize_ipiqs("muninit"); 310 #endif 311 312 #ifdef INVARIANTS 313 /* 314 * memuse is only correct in aggregation. Due to memory being allocated 315 * on one cpu and freed on another individual array entries may be 316 * negative or positive (canceling each other out). 317 */ 318 for (i = ttl = 0; i < ncpus; ++i) 319 ttl += type->ks_memuse[i]; 320 if (ttl) { 321 kprintf("malloc_uninit: %ld bytes of '%s' still allocated on cpu %d\n", 322 ttl, type->ks_shortdesc, i); 323 } 324 #endif 325 if (type == kmemstatistics) { 326 kmemstatistics = type->ks_next; 327 } else { 328 for (t = kmemstatistics; t->ks_next != NULL; t = t->ks_next) { 329 if (t->ks_next == type) { 330 t->ks_next = type->ks_next; 331 break; 332 } 333 } 334 } 335 type->ks_next = NULL; 336 type->ks_limit = 0; 337 } 338 339 /* 340 * Increase the kmalloc pool limit for the specified pool. No changes 341 * are the made if the pool would shrink. 342 */ 343 void 344 kmalloc_raise_limit(struct malloc_type *type, size_t bytes) 345 { 346 if (type->ks_limit == 0) 347 malloc_init(type); 348 if (bytes == 0) 349 bytes = KvaSize; 350 if (type->ks_limit < bytes) 351 type->ks_limit = bytes; 352 } 353 354 /* 355 * Dynamically create a malloc pool. This function is a NOP if *typep is 356 * already non-NULL. 357 */ 358 void 359 kmalloc_create(struct malloc_type **typep, const char *descr) 360 { 361 struct malloc_type *type; 362 363 if (*typep == NULL) { 364 type = kmalloc(sizeof(*type), M_TEMP, M_WAITOK | M_ZERO); 365 type->ks_magic = M_MAGIC; 366 type->ks_shortdesc = descr; 367 malloc_init(type); 368 *typep = type; 369 } 370 } 371 372 /* 373 * Destroy a dynamically created malloc pool. This function is a NOP if 374 * the pool has already been destroyed. 375 */ 376 void 377 kmalloc_destroy(struct malloc_type **typep) 378 { 379 if (*typep != NULL) { 380 malloc_uninit(*typep); 381 kfree(*typep, M_TEMP); 382 *typep = NULL; 383 } 384 } 385 386 /* 387 * Calculate the zone index for the allocation request size and set the 388 * allocation request size to that particular zone's chunk size. 389 */ 390 static __inline int 391 zoneindex(unsigned long *bytes) 392 { 393 unsigned int n = (unsigned int)*bytes; /* unsigned for shift opt */ 394 if (n < 128) { 395 *bytes = n = (n + 7) & ~7; 396 return(n / 8 - 1); /* 8 byte chunks, 16 zones */ 397 } 398 if (n < 256) { 399 *bytes = n = (n + 15) & ~15; 400 return(n / 16 + 7); 401 } 402 if (n < 8192) { 403 if (n < 512) { 404 *bytes = n = (n + 31) & ~31; 405 return(n / 32 + 15); 406 } 407 if (n < 1024) { 408 *bytes = n = (n + 63) & ~63; 409 return(n / 64 + 23); 410 } 411 if (n < 2048) { 412 *bytes = n = (n + 127) & ~127; 413 return(n / 128 + 31); 414 } 415 if (n < 4096) { 416 *bytes = n = (n + 255) & ~255; 417 return(n / 256 + 39); 418 } 419 *bytes = n = (n + 511) & ~511; 420 return(n / 512 + 47); 421 } 422 #if ZALLOC_ZONE_LIMIT > 8192 423 if (n < 16384) { 424 *bytes = n = (n + 1023) & ~1023; 425 return(n / 1024 + 55); 426 } 427 #endif 428 #if ZALLOC_ZONE_LIMIT > 16384 429 if (n < 32768) { 430 *bytes = n = (n + 2047) & ~2047; 431 return(n / 2048 + 63); 432 } 433 #endif 434 panic("Unexpected byte count %d", n); 435 return(0); 436 } 437 438 /* 439 * kmalloc() (SLAB ALLOCATOR) 440 * 441 * Allocate memory via the slab allocator. If the request is too large, 442 * or if it page-aligned beyond a certain size, we fall back to the 443 * KMEM subsystem. A SLAB tracking descriptor must be specified, use 444 * &SlabMisc if you don't care. 445 * 446 * M_RNOWAIT - don't block. 447 * M_NULLOK - return NULL instead of blocking. 448 * M_ZERO - zero the returned memory. 449 * M_USE_RESERVE - allow greater drawdown of the free list 450 * M_USE_INTERRUPT_RESERVE - allow the freelist to be exhausted 451 * 452 * MPSAFE 453 */ 454 void * 455 kmalloc(unsigned long size, struct malloc_type *type, int flags) 456 { 457 SLZone *z; 458 SLChunk *chunk; 459 #ifdef SMP 460 SLChunk *bchunk; 461 #endif 462 SLGlobalData *slgd; 463 struct globaldata *gd; 464 int zi; 465 #ifdef INVARIANTS 466 int i; 467 #endif 468 469 logmemory_quick(malloc_beg); 470 gd = mycpu; 471 slgd = &gd->gd_slab; 472 473 /* 474 * XXX silly to have this in the critical path. 475 */ 476 if (type->ks_limit == 0) { 477 crit_enter(); 478 if (type->ks_limit == 0) 479 malloc_init(type); 480 crit_exit(); 481 } 482 ++type->ks_calls; 483 484 /* 485 * Handle the case where the limit is reached. Panic if we can't return 486 * NULL. The original malloc code looped, but this tended to 487 * simply deadlock the computer. 488 * 489 * ks_loosememuse is an up-only limit that is NOT MP-synchronized, used 490 * to determine if a more complete limit check should be done. The 491 * actual memory use is tracked via ks_memuse[cpu]. 492 */ 493 while (type->ks_loosememuse >= type->ks_limit) { 494 int i; 495 long ttl; 496 497 for (i = ttl = 0; i < ncpus; ++i) 498 ttl += type->ks_memuse[i]; 499 type->ks_loosememuse = ttl; /* not MP synchronized */ 500 if ((ssize_t)ttl < 0) /* deal with occassional race */ 501 ttl = 0; 502 if (ttl >= type->ks_limit) { 503 if (flags & M_NULLOK) { 504 logmemory(malloc_end, NULL, type, size, flags); 505 return(NULL); 506 } 507 panic("%s: malloc limit exceeded", type->ks_shortdesc); 508 } 509 } 510 511 /* 512 * Handle the degenerate size == 0 case. Yes, this does happen. 513 * Return a special pointer. This is to maintain compatibility with 514 * the original malloc implementation. Certain devices, such as the 515 * adaptec driver, not only allocate 0 bytes, they check for NULL and 516 * also realloc() later on. Joy. 517 */ 518 if (size == 0) { 519 logmemory(malloc_end, ZERO_LENGTH_PTR, type, size, flags); 520 return(ZERO_LENGTH_PTR); 521 } 522 523 /* 524 * Handle hysteresis from prior frees here in malloc(). We cannot 525 * safely manipulate the kernel_map in free() due to free() possibly 526 * being called via an IPI message or from sensitive interrupt code. 527 * 528 * NOTE: ku_pagecnt must be cleared before we free the slab or we 529 * might race another cpu allocating the kva and setting 530 * ku_pagecnt. 531 */ 532 while (slgd->NFreeZones > ZONE_RELS_THRESH && (flags & M_RNOWAIT) == 0) { 533 crit_enter(); 534 if (slgd->NFreeZones > ZONE_RELS_THRESH) { /* crit sect race */ 535 int *kup; 536 537 z = slgd->FreeZones; 538 slgd->FreeZones = z->z_Next; 539 --slgd->NFreeZones; 540 kup = btokup(z); 541 *kup = 0; 542 kmem_slab_free(z, ZoneSize); /* may block */ 543 atomic_add_int(&ZoneGenAlloc, -(int)ZoneSize / 1024); 544 } 545 crit_exit(); 546 } 547 548 /* 549 * XXX handle oversized frees that were queued from kfree(). 550 */ 551 while (slgd->FreeOvZones && (flags & M_RNOWAIT) == 0) { 552 crit_enter(); 553 if ((z = slgd->FreeOvZones) != NULL) { 554 vm_size_t tsize; 555 556 KKASSERT(z->z_Magic == ZALLOC_OVSZ_MAGIC); 557 slgd->FreeOvZones = z->z_Next; 558 tsize = z->z_ChunkSize; 559 kmem_slab_free(z, tsize); /* may block */ 560 atomic_add_int(&ZoneBigAlloc, -(int)tsize / 1024); 561 } 562 crit_exit(); 563 } 564 565 /* 566 * Handle large allocations directly. There should not be very many of 567 * these so performance is not a big issue. 568 * 569 * The backend allocator is pretty nasty on a SMP system. Use the 570 * slab allocator for one and two page-sized chunks even though we lose 571 * some efficiency. XXX maybe fix mmio and the elf loader instead. 572 */ 573 if (size >= ZoneLimit || ((size & PAGE_MASK) == 0 && size > PAGE_SIZE*2)) { 574 int *kup; 575 576 size = round_page(size); 577 chunk = kmem_slab_alloc(size, PAGE_SIZE, flags); 578 if (chunk == NULL) { 579 logmemory(malloc_end, NULL, type, size, flags); 580 return(NULL); 581 } 582 atomic_add_int(&ZoneBigAlloc, (int)size / 1024); 583 flags &= ~M_ZERO; /* result already zero'd if M_ZERO was set */ 584 flags |= M_PASSIVE_ZERO; 585 kup = btokup(chunk); 586 *kup = size / PAGE_SIZE; 587 crit_enter(); 588 goto done; 589 } 590 591 /* 592 * Attempt to allocate out of an existing zone. First try the free list, 593 * then allocate out of unallocated space. If we find a good zone move 594 * it to the head of the list so later allocations find it quickly 595 * (we might have thousands of zones in the list). 596 * 597 * Note: zoneindex() will panic of size is too large. 598 */ 599 zi = zoneindex(&size); 600 KKASSERT(zi < NZONES); 601 crit_enter(); 602 603 if ((z = slgd->ZoneAry[zi]) != NULL) { 604 /* 605 * Locate a chunk - we have to have at least one. If this is the 606 * last chunk go ahead and do the work to retrieve chunks freed 607 * from remote cpus, and if the zone is still empty move it off 608 * the ZoneAry. 609 */ 610 if (--z->z_NFree <= 0) { 611 KKASSERT(z->z_NFree == 0); 612 613 #ifdef SMP 614 /* 615 * WARNING! This code competes with other cpus. It is ok 616 * for us to not drain RChunks here but we might as well, and 617 * it is ok if more accumulate after we're done. 618 * 619 * Set RSignal before pulling rchunks off, indicating that we 620 * will be moving ourselves off of the ZoneAry. Remote ends will 621 * read RSignal before putting rchunks on thus interlocking 622 * their IPI signaling. 623 */ 624 if (z->z_RChunks == NULL) 625 atomic_swap_int(&z->z_RSignal, 1); 626 627 while ((bchunk = z->z_RChunks) != NULL) { 628 cpu_ccfence(); 629 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) { 630 *z->z_LChunksp = bchunk; 631 while (bchunk) { 632 chunk_mark_free(z, bchunk); 633 z->z_LChunksp = &bchunk->c_Next; 634 bchunk = bchunk->c_Next; 635 ++z->z_NFree; 636 } 637 break; 638 } 639 } 640 #endif 641 /* 642 * Remove from the zone list if no free chunks remain. 643 * Clear RSignal 644 */ 645 if (z->z_NFree == 0) { 646 slgd->ZoneAry[zi] = z->z_Next; 647 z->z_Next = NULL; 648 } else { 649 z->z_RSignal = 0; 650 } 651 } 652 653 /* 654 * Fast path, we have chunks available in z_LChunks. 655 */ 656 chunk = z->z_LChunks; 657 if (chunk) { 658 chunk_mark_allocated(z, chunk); 659 z->z_LChunks = chunk->c_Next; 660 if (z->z_LChunks == NULL) 661 z->z_LChunksp = &z->z_LChunks; 662 goto done; 663 } 664 665 /* 666 * No chunks are available in LChunks, the free chunk MUST be 667 * in the never-before-used memory area, controlled by UIndex. 668 * 669 * The consequences are very serious if our zone got corrupted so 670 * we use an explicit panic rather than a KASSERT. 671 */ 672 if (z->z_UIndex + 1 != z->z_NMax) 673 ++z->z_UIndex; 674 else 675 z->z_UIndex = 0; 676 677 if (z->z_UIndex == z->z_UEndIndex) 678 panic("slaballoc: corrupted zone"); 679 680 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 681 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 682 flags &= ~M_ZERO; 683 flags |= M_PASSIVE_ZERO; 684 } 685 chunk_mark_allocated(z, chunk); 686 goto done; 687 } 688 689 /* 690 * If all zones are exhausted we need to allocate a new zone for this 691 * index. Use M_ZERO to take advantage of pre-zerod pages. Also see 692 * UAlloc use above in regards to M_ZERO. Note that when we are reusing 693 * a zone from the FreeZones list UAlloc'd data will not be zero'd, and 694 * we do not pre-zero it because we do not want to mess up the L1 cache. 695 * 696 * At least one subsystem, the tty code (see CROUND) expects power-of-2 697 * allocations to be power-of-2 aligned. We maintain compatibility by 698 * adjusting the base offset below. 699 */ 700 { 701 int off; 702 int *kup; 703 704 if ((z = slgd->FreeZones) != NULL) { 705 slgd->FreeZones = z->z_Next; 706 --slgd->NFreeZones; 707 bzero(z, sizeof(SLZone)); 708 z->z_Flags |= SLZF_UNOTZEROD; 709 } else { 710 z = kmem_slab_alloc(ZoneSize, ZoneSize, flags|M_ZERO); 711 if (z == NULL) 712 goto fail; 713 atomic_add_int(&ZoneGenAlloc, (int)ZoneSize / 1024); 714 } 715 716 /* 717 * How big is the base structure? 718 */ 719 #if defined(INVARIANTS) 720 /* 721 * Make room for z_Bitmap. An exact calculation is somewhat more 722 * complicated so don't make an exact calculation. 723 */ 724 off = offsetof(SLZone, z_Bitmap[(ZoneSize / size + 31) / 32]); 725 bzero(z->z_Bitmap, (ZoneSize / size + 31) / 8); 726 #else 727 off = sizeof(SLZone); 728 #endif 729 730 /* 731 * Guarentee power-of-2 alignment for power-of-2-sized chunks. 732 * Otherwise just 8-byte align the data. 733 */ 734 if ((size | (size - 1)) + 1 == (size << 1)) 735 off = (off + size - 1) & ~(size - 1); 736 else 737 off = (off + MIN_CHUNK_MASK) & ~MIN_CHUNK_MASK; 738 z->z_Magic = ZALLOC_SLAB_MAGIC; 739 z->z_ZoneIndex = zi; 740 z->z_NMax = (ZoneSize - off) / size; 741 z->z_NFree = z->z_NMax - 1; 742 z->z_BasePtr = (char *)z + off; 743 z->z_UIndex = z->z_UEndIndex = slgd->JunkIndex % z->z_NMax; 744 z->z_ChunkSize = size; 745 z->z_CpuGd = gd; 746 z->z_Cpu = gd->gd_cpuid; 747 z->z_LChunksp = &z->z_LChunks; 748 chunk = (SLChunk *)(z->z_BasePtr + z->z_UIndex * size); 749 z->z_Next = slgd->ZoneAry[zi]; 750 slgd->ZoneAry[zi] = z; 751 if ((z->z_Flags & SLZF_UNOTZEROD) == 0) { 752 flags &= ~M_ZERO; /* already zero'd */ 753 flags |= M_PASSIVE_ZERO; 754 } 755 kup = btokup(z); 756 *kup = -(z->z_Cpu + 1); /* -1 to -(N+1) */ 757 chunk_mark_allocated(z, chunk); 758 759 /* 760 * Slide the base index for initial allocations out of the next 761 * zone we create so we do not over-weight the lower part of the 762 * cpu memory caches. 763 */ 764 slgd->JunkIndex = (slgd->JunkIndex + ZALLOC_SLAB_SLIDE) 765 & (ZALLOC_MAX_ZONE_SIZE - 1); 766 } 767 768 done: 769 ++type->ks_inuse[gd->gd_cpuid]; 770 type->ks_memuse[gd->gd_cpuid] += size; 771 type->ks_loosememuse += size; /* not MP synchronized */ 772 crit_exit(); 773 774 if (flags & M_ZERO) 775 bzero(chunk, size); 776 #ifdef INVARIANTS 777 else if ((flags & (M_ZERO|M_PASSIVE_ZERO)) == 0) { 778 if (use_malloc_pattern) { 779 for (i = 0; i < size; i += sizeof(int)) { 780 *(int *)((char *)chunk + i) = -1; 781 } 782 } 783 chunk->c_Next = (void *)-1; /* avoid accidental double-free check */ 784 } 785 #endif 786 logmemory(malloc_end, chunk, type, size, flags); 787 return(chunk); 788 fail: 789 crit_exit(); 790 logmemory(malloc_end, NULL, type, size, flags); 791 return(NULL); 792 } 793 794 /* 795 * kernel realloc. (SLAB ALLOCATOR) (MP SAFE) 796 * 797 * Generally speaking this routine is not called very often and we do 798 * not attempt to optimize it beyond reusing the same pointer if the 799 * new size fits within the chunking of the old pointer's zone. 800 */ 801 void * 802 krealloc(void *ptr, unsigned long size, struct malloc_type *type, int flags) 803 { 804 unsigned long osize; 805 SLZone *z; 806 void *nptr; 807 int *kup; 808 809 KKASSERT((flags & M_ZERO) == 0); /* not supported */ 810 811 if (ptr == NULL || ptr == ZERO_LENGTH_PTR) 812 return(kmalloc(size, type, flags)); 813 if (size == 0) { 814 kfree(ptr, type); 815 return(NULL); 816 } 817 818 /* 819 * Handle oversized allocations. XXX we really should require that a 820 * size be passed to free() instead of this nonsense. 821 */ 822 kup = btokup(ptr); 823 if (*kup > 0) { 824 osize = *kup << PAGE_SHIFT; 825 if (osize == round_page(size)) 826 return(ptr); 827 if ((nptr = kmalloc(size, type, flags)) == NULL) 828 return(NULL); 829 bcopy(ptr, nptr, min(size, osize)); 830 kfree(ptr, type); 831 return(nptr); 832 } 833 834 /* 835 * Get the original allocation's zone. If the new request winds up 836 * using the same chunk size we do not have to do anything. 837 */ 838 z = (SLZone *)((uintptr_t)ptr & ZoneMask); 839 kup = btokup(z); 840 KKASSERT(*kup < 0); 841 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 842 843 /* 844 * Allocate memory for the new request size. Note that zoneindex has 845 * already adjusted the request size to the appropriate chunk size, which 846 * should optimize our bcopy(). Then copy and return the new pointer. 847 * 848 * Resizing a non-power-of-2 allocation to a power-of-2 size does not 849 * necessary align the result. 850 * 851 * We can only zoneindex (to align size to the chunk size) if the new 852 * size is not too large. 853 */ 854 if (size < ZoneLimit) { 855 zoneindex(&size); 856 if (z->z_ChunkSize == size) 857 return(ptr); 858 } 859 if ((nptr = kmalloc(size, type, flags)) == NULL) 860 return(NULL); 861 bcopy(ptr, nptr, min(size, z->z_ChunkSize)); 862 kfree(ptr, type); 863 return(nptr); 864 } 865 866 /* 867 * Return the kmalloc limit for this type, in bytes. 868 */ 869 long 870 kmalloc_limit(struct malloc_type *type) 871 { 872 if (type->ks_limit == 0) { 873 crit_enter(); 874 if (type->ks_limit == 0) 875 malloc_init(type); 876 crit_exit(); 877 } 878 return(type->ks_limit); 879 } 880 881 /* 882 * Allocate a copy of the specified string. 883 * 884 * (MP SAFE) (MAY BLOCK) 885 */ 886 char * 887 kstrdup(const char *str, struct malloc_type *type) 888 { 889 int zlen; /* length inclusive of terminating NUL */ 890 char *nstr; 891 892 if (str == NULL) 893 return(NULL); 894 zlen = strlen(str) + 1; 895 nstr = kmalloc(zlen, type, M_WAITOK); 896 bcopy(str, nstr, zlen); 897 return(nstr); 898 } 899 900 #ifdef SMP 901 /* 902 * Notify our cpu that a remote cpu has freed some chunks in a zone that 903 * we own. RCount will be bumped so the memory should be good, but validate 904 * that it really is. 905 */ 906 static 907 void 908 kfree_remote(void *ptr) 909 { 910 SLGlobalData *slgd; 911 SLChunk *bchunk; 912 SLZone *z; 913 int nfree; 914 int *kup; 915 916 slgd = &mycpu->gd_slab; 917 z = ptr; 918 kup = btokup(z); 919 KKASSERT(*kup == -((int)mycpuid + 1)); 920 KKASSERT(z->z_RCount > 0); 921 atomic_subtract_int(&z->z_RCount, 1); 922 923 logmemory(free_rem_beg, z, NULL, 0, 0); 924 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 925 KKASSERT(z->z_Cpu == mycpu->gd_cpuid); 926 nfree = z->z_NFree; 927 928 /* 929 * Indicate that we will no longer be off of the ZoneAry by 930 * clearing RSignal. 931 */ 932 if (z->z_RChunks) 933 z->z_RSignal = 0; 934 935 /* 936 * Atomically extract the bchunks list and then process it back 937 * into the lchunks list. We want to append our bchunks to the 938 * lchunks list and not prepend since we likely do not have 939 * cache mastership of the related data (not that it helps since 940 * we are using c_Next). 941 */ 942 while ((bchunk = z->z_RChunks) != NULL) { 943 cpu_ccfence(); 944 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, NULL)) { 945 *z->z_LChunksp = bchunk; 946 while (bchunk) { 947 chunk_mark_free(z, bchunk); 948 z->z_LChunksp = &bchunk->c_Next; 949 bchunk = bchunk->c_Next; 950 ++z->z_NFree; 951 } 952 break; 953 } 954 } 955 if (z->z_NFree && nfree == 0) { 956 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 957 slgd->ZoneAry[z->z_ZoneIndex] = z; 958 } 959 960 /* 961 * If the zone becomes totally free, and there are other zones we 962 * can allocate from, move this zone to the FreeZones list. Since 963 * this code can be called from an IPI callback, do *NOT* try to mess 964 * with kernel_map here. Hysteresis will be performed at malloc() time. 965 * 966 * Do not move the zone if there is an IPI inflight, otherwise MP 967 * races can result in our free_remote code accessing a destroyed 968 * zone. 969 */ 970 if (z->z_NFree == z->z_NMax && 971 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) && 972 z->z_RCount == 0 973 ) { 974 SLZone **pz; 975 int *kup; 976 977 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; 978 z != *pz; 979 pz = &(*pz)->z_Next) { 980 ; 981 } 982 *pz = z->z_Next; 983 z->z_Magic = -1; 984 z->z_Next = slgd->FreeZones; 985 slgd->FreeZones = z; 986 ++slgd->NFreeZones; 987 kup = btokup(z); 988 *kup = 0; 989 } 990 logmemory(free_rem_end, z, bchunk, 0, 0); 991 } 992 993 #endif 994 995 /* 996 * free (SLAB ALLOCATOR) 997 * 998 * Free a memory block previously allocated by malloc. Note that we do not 999 * attempt to update ks_loosememuse as MP races could prevent us from 1000 * checking memory limits in malloc. 1001 * 1002 * MPSAFE 1003 */ 1004 void 1005 kfree(void *ptr, struct malloc_type *type) 1006 { 1007 SLZone *z; 1008 SLChunk *chunk; 1009 SLGlobalData *slgd; 1010 struct globaldata *gd; 1011 int *kup; 1012 unsigned long size; 1013 #ifdef SMP 1014 SLChunk *bchunk; 1015 int rsignal; 1016 #endif 1017 1018 logmemory_quick(free_beg); 1019 gd = mycpu; 1020 slgd = &gd->gd_slab; 1021 1022 if (ptr == NULL) 1023 panic("trying to free NULL pointer"); 1024 1025 /* 1026 * Handle special 0-byte allocations 1027 */ 1028 if (ptr == ZERO_LENGTH_PTR) { 1029 logmemory(free_zero, ptr, type, -1, 0); 1030 logmemory_quick(free_end); 1031 return; 1032 } 1033 1034 /* 1035 * Panic on bad malloc type 1036 */ 1037 if (type->ks_magic != M_MAGIC) 1038 panic("free: malloc type lacks magic"); 1039 1040 /* 1041 * Handle oversized allocations. XXX we really should require that a 1042 * size be passed to free() instead of this nonsense. 1043 * 1044 * This code is never called via an ipi. 1045 */ 1046 kup = btokup(ptr); 1047 if (*kup > 0) { 1048 size = *kup << PAGE_SHIFT; 1049 *kup = 0; 1050 #ifdef INVARIANTS 1051 KKASSERT(sizeof(weirdary) <= size); 1052 bcopy(weirdary, ptr, sizeof(weirdary)); 1053 #endif 1054 /* 1055 * NOTE: For oversized allocations we do not record the 1056 * originating cpu. It gets freed on the cpu calling 1057 * kfree(). The statistics are in aggregate. 1058 * 1059 * note: XXX we have still inherited the interrupts-can't-block 1060 * assumption. An interrupt thread does not bump 1061 * gd_intr_nesting_level so check TDF_INTTHREAD. This is 1062 * primarily until we can fix softupdate's assumptions about free(). 1063 */ 1064 crit_enter(); 1065 --type->ks_inuse[gd->gd_cpuid]; 1066 type->ks_memuse[gd->gd_cpuid] -= size; 1067 if (mycpu->gd_intr_nesting_level || 1068 (gd->gd_curthread->td_flags & TDF_INTTHREAD)) 1069 { 1070 logmemory(free_ovsz_delayed, ptr, type, size, 0); 1071 z = (SLZone *)ptr; 1072 z->z_Magic = ZALLOC_OVSZ_MAGIC; 1073 z->z_Next = slgd->FreeOvZones; 1074 z->z_ChunkSize = size; 1075 slgd->FreeOvZones = z; 1076 crit_exit(); 1077 } else { 1078 crit_exit(); 1079 logmemory(free_ovsz, ptr, type, size, 0); 1080 kmem_slab_free(ptr, size); /* may block */ 1081 atomic_add_int(&ZoneBigAlloc, -(int)size / 1024); 1082 } 1083 logmemory_quick(free_end); 1084 return; 1085 } 1086 1087 /* 1088 * Zone case. Figure out the zone based on the fact that it is 1089 * ZoneSize aligned. 1090 */ 1091 z = (SLZone *)((uintptr_t)ptr & ZoneMask); 1092 kup = btokup(z); 1093 KKASSERT(*kup < 0); 1094 KKASSERT(z->z_Magic == ZALLOC_SLAB_MAGIC); 1095 1096 /* 1097 * If we do not own the zone then use atomic ops to free to the 1098 * remote cpu linked list and notify the target zone using a 1099 * passive message. 1100 * 1101 * The target zone cannot be deallocated while we own a chunk of it, 1102 * so the zone header's storage is stable until the very moment 1103 * we adjust z_RChunks. After that we cannot safely dereference (z). 1104 * 1105 * (no critical section needed) 1106 */ 1107 if (z->z_CpuGd != gd) { 1108 #ifdef SMP 1109 /* 1110 * Making these adjustments now allow us to avoid passing (type) 1111 * to the remote cpu. Note that ks_inuse/ks_memuse is being 1112 * adjusted on OUR cpu, not the zone cpu, but it should all still 1113 * sum up properly and cancel out. 1114 */ 1115 crit_enter(); 1116 --type->ks_inuse[gd->gd_cpuid]; 1117 type->ks_memuse[gd->gd_cpuid] -= z->z_ChunkSize; 1118 crit_exit(); 1119 1120 /* 1121 * WARNING! This code competes with other cpus. Once we 1122 * successfully link the chunk to RChunks the remote 1123 * cpu can rip z's storage out from under us. 1124 * 1125 * Bumping RCount prevents z's storage from getting 1126 * ripped out. 1127 */ 1128 rsignal = z->z_RSignal; 1129 cpu_lfence(); 1130 if (rsignal) 1131 atomic_add_int(&z->z_RCount, 1); 1132 1133 chunk = ptr; 1134 for (;;) { 1135 bchunk = z->z_RChunks; 1136 cpu_ccfence(); 1137 chunk->c_Next = bchunk; 1138 cpu_sfence(); 1139 1140 if (atomic_cmpset_ptr(&z->z_RChunks, bchunk, chunk)) 1141 break; 1142 } 1143 1144 /* 1145 * We have to signal the remote cpu if our actions will cause 1146 * the remote zone to be placed back on ZoneAry so it can 1147 * move the zone back on. 1148 * 1149 * We only need to deal with NULL->non-NULL RChunk transitions 1150 * and only if z_RSignal is set. We interlock by reading rsignal 1151 * before adding our chunk to RChunks. This should result in 1152 * virtually no IPI traffic. 1153 * 1154 * We can use a passive IPI to reduce overhead even further. 1155 */ 1156 if (bchunk == NULL && rsignal) { 1157 logmemory(free_request, ptr, type, z->z_ChunkSize, 0); 1158 lwkt_send_ipiq_passive(z->z_CpuGd, kfree_remote, z); 1159 /* z can get ripped out from under us from this point on */ 1160 } else if (rsignal) { 1161 atomic_subtract_int(&z->z_RCount, 1); 1162 /* z can get ripped out from under us from this point on */ 1163 } 1164 #else 1165 panic("Corrupt SLZone"); 1166 #endif 1167 logmemory_quick(free_end); 1168 return; 1169 } 1170 1171 /* 1172 * kfree locally 1173 */ 1174 logmemory(free_chunk, ptr, type, z->z_ChunkSize, 0); 1175 1176 crit_enter(); 1177 chunk = ptr; 1178 chunk_mark_free(z, chunk); 1179 1180 /* 1181 * Put weird data into the memory to detect modifications after freeing, 1182 * illegal pointer use after freeing (we should fault on the odd address), 1183 * and so forth. XXX needs more work, see the old malloc code. 1184 */ 1185 #ifdef INVARIANTS 1186 if (z->z_ChunkSize < sizeof(weirdary)) 1187 bcopy(weirdary, chunk, z->z_ChunkSize); 1188 else 1189 bcopy(weirdary, chunk, sizeof(weirdary)); 1190 #endif 1191 1192 /* 1193 * Add this free non-zero'd chunk to a linked list for reuse. Add 1194 * to the front of the linked list so it is more likely to be 1195 * reallocated, since it is already in our L1 cache. 1196 */ 1197 #ifdef INVARIANTS 1198 if ((vm_offset_t)chunk < KvaStart || (vm_offset_t)chunk >= KvaEnd) 1199 panic("BADFREE %p", chunk); 1200 #endif 1201 chunk->c_Next = z->z_LChunks; 1202 z->z_LChunks = chunk; 1203 if (chunk->c_Next == NULL) 1204 z->z_LChunksp = &chunk->c_Next; 1205 1206 #ifdef INVARIANTS 1207 if (chunk->c_Next && (vm_offset_t)chunk->c_Next < KvaStart) 1208 panic("BADFREE2"); 1209 #endif 1210 1211 /* 1212 * Bump the number of free chunks. If it becomes non-zero the zone 1213 * must be added back onto the appropriate list. 1214 */ 1215 if (z->z_NFree++ == 0) { 1216 z->z_Next = slgd->ZoneAry[z->z_ZoneIndex]; 1217 slgd->ZoneAry[z->z_ZoneIndex] = z; 1218 } 1219 1220 --type->ks_inuse[z->z_Cpu]; 1221 type->ks_memuse[z->z_Cpu] -= z->z_ChunkSize; 1222 1223 /* 1224 * If the zone becomes totally free, and there are other zones we 1225 * can allocate from, move this zone to the FreeZones list. Since 1226 * this code can be called from an IPI callback, do *NOT* try to mess 1227 * with kernel_map here. Hysteresis will be performed at malloc() time. 1228 */ 1229 if (z->z_NFree == z->z_NMax && 1230 (z->z_Next || slgd->ZoneAry[z->z_ZoneIndex] != z) && 1231 z->z_RCount == 0 1232 ) { 1233 SLZone **pz; 1234 int *kup; 1235 1236 for (pz = &slgd->ZoneAry[z->z_ZoneIndex]; z != *pz; pz = &(*pz)->z_Next) 1237 ; 1238 *pz = z->z_Next; 1239 z->z_Magic = -1; 1240 z->z_Next = slgd->FreeZones; 1241 slgd->FreeZones = z; 1242 ++slgd->NFreeZones; 1243 kup = btokup(z); 1244 *kup = 0; 1245 } 1246 logmemory_quick(free_end); 1247 crit_exit(); 1248 } 1249 1250 #if defined(INVARIANTS) 1251 1252 /* 1253 * Helper routines for sanity checks 1254 */ 1255 static 1256 void 1257 chunk_mark_allocated(SLZone *z, void *chunk) 1258 { 1259 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize; 1260 __uint32_t *bitptr; 1261 1262 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0); 1263 KASSERT(bitdex >= 0 && bitdex < z->z_NMax, 1264 ("memory chunk %p bit index %d is illegal", chunk, bitdex)); 1265 bitptr = &z->z_Bitmap[bitdex >> 5]; 1266 bitdex &= 31; 1267 KASSERT((*bitptr & (1 << bitdex)) == 0, 1268 ("memory chunk %p is already allocated!", chunk)); 1269 *bitptr |= 1 << bitdex; 1270 } 1271 1272 static 1273 void 1274 chunk_mark_free(SLZone *z, void *chunk) 1275 { 1276 int bitdex = ((char *)chunk - (char *)z->z_BasePtr) / z->z_ChunkSize; 1277 __uint32_t *bitptr; 1278 1279 KKASSERT((((intptr_t)chunk ^ (intptr_t)z) & ZoneMask) == 0); 1280 KASSERT(bitdex >= 0 && bitdex < z->z_NMax, 1281 ("memory chunk %p bit index %d is illegal!", chunk, bitdex)); 1282 bitptr = &z->z_Bitmap[bitdex >> 5]; 1283 bitdex &= 31; 1284 KASSERT((*bitptr & (1 << bitdex)) != 0, 1285 ("memory chunk %p is already free!", chunk)); 1286 *bitptr &= ~(1 << bitdex); 1287 } 1288 1289 #endif 1290 1291 /* 1292 * kmem_slab_alloc() 1293 * 1294 * Directly allocate and wire kernel memory in PAGE_SIZE chunks with the 1295 * specified alignment. M_* flags are expected in the flags field. 1296 * 1297 * Alignment must be a multiple of PAGE_SIZE. 1298 * 1299 * NOTE! XXX For the moment we use vm_map_entry_reserve/release(), 1300 * but when we move zalloc() over to use this function as its backend 1301 * we will have to switch to kreserve/krelease and call reserve(0) 1302 * after the new space is made available. 1303 * 1304 * Interrupt code which has preempted other code is not allowed to 1305 * use PQ_CACHE pages. However, if an interrupt thread is run 1306 * non-preemptively or blocks and then runs non-preemptively, then 1307 * it is free to use PQ_CACHE pages. 1308 */ 1309 static void * 1310 kmem_slab_alloc(vm_size_t size, vm_offset_t align, int flags) 1311 { 1312 vm_size_t i; 1313 vm_offset_t addr; 1314 int count, vmflags, base_vmflags; 1315 vm_page_t mp[ZALLOC_MAX_ZONE_SIZE / PAGE_SIZE]; 1316 thread_t td; 1317 1318 size = round_page(size); 1319 addr = vm_map_min(&kernel_map); 1320 1321 /* 1322 * Reserve properly aligned space from kernel_map. RNOWAIT allocations 1323 * cannot block. 1324 */ 1325 if (flags & M_RNOWAIT) { 1326 if (lwkt_trytoken(&vm_token) == 0) 1327 return(NULL); 1328 } else { 1329 lwkt_gettoken(&vm_token); 1330 } 1331 count = vm_map_entry_reserve(MAP_RESERVE_COUNT); 1332 crit_enter(); 1333 vm_map_lock(&kernel_map); 1334 if (vm_map_findspace(&kernel_map, addr, size, align, 0, &addr)) { 1335 vm_map_unlock(&kernel_map); 1336 if ((flags & M_NULLOK) == 0) 1337 panic("kmem_slab_alloc(): kernel_map ran out of space!"); 1338 vm_map_entry_release(count); 1339 crit_exit(); 1340 lwkt_reltoken(&vm_token); 1341 return(NULL); 1342 } 1343 1344 /* 1345 * kernel_object maps 1:1 to kernel_map. 1346 */ 1347 vm_object_reference(&kernel_object); 1348 vm_map_insert(&kernel_map, &count, 1349 &kernel_object, addr, addr, addr + size, 1350 VM_MAPTYPE_NORMAL, 1351 VM_PROT_ALL, VM_PROT_ALL, 1352 0); 1353 1354 td = curthread; 1355 1356 base_vmflags = 0; 1357 if (flags & M_ZERO) 1358 base_vmflags |= VM_ALLOC_ZERO; 1359 if (flags & M_USE_RESERVE) 1360 base_vmflags |= VM_ALLOC_SYSTEM; 1361 if (flags & M_USE_INTERRUPT_RESERVE) 1362 base_vmflags |= VM_ALLOC_INTERRUPT; 1363 if ((flags & (M_RNOWAIT|M_WAITOK)) == 0) { 1364 panic("kmem_slab_alloc: bad flags %08x (%p)", 1365 flags, ((int **)&size)[-1]); 1366 } 1367 1368 1369 /* 1370 * Allocate the pages. Do not mess with the PG_ZERO flag yet. 1371 */ 1372 for (i = 0; i < size; i += PAGE_SIZE) { 1373 vm_page_t m; 1374 1375 /* 1376 * VM_ALLOC_NORMAL can only be set if we are not preempting. 1377 * 1378 * VM_ALLOC_SYSTEM is automatically set if we are preempting and 1379 * M_WAITOK was specified as an alternative (i.e. M_USE_RESERVE is 1380 * implied in this case), though I'm not sure if we really need to 1381 * do that. 1382 */ 1383 vmflags = base_vmflags; 1384 if (flags & M_WAITOK) { 1385 if (td->td_preempted) 1386 vmflags |= VM_ALLOC_SYSTEM; 1387 else 1388 vmflags |= VM_ALLOC_NORMAL; 1389 } 1390 1391 m = vm_page_alloc(&kernel_object, OFF_TO_IDX(addr + i), vmflags); 1392 if ((i / PAGE_SIZE) < (sizeof(mp) / sizeof(mp[0]))) 1393 mp[i / PAGE_SIZE] = m; 1394 1395 /* 1396 * If the allocation failed we either return NULL or we retry. 1397 * 1398 * If M_WAITOK is specified we wait for more memory and retry. 1399 * If M_WAITOK is specified from a preemption we yield instead of 1400 * wait. Livelock will not occur because the interrupt thread 1401 * will not be preempting anyone the second time around after the 1402 * yield. 1403 */ 1404 if (m == NULL) { 1405 if (flags & M_WAITOK) { 1406 if (td->td_preempted) { 1407 vm_map_unlock(&kernel_map); 1408 lwkt_switch(); 1409 vm_map_lock(&kernel_map); 1410 } else { 1411 vm_map_unlock(&kernel_map); 1412 vm_wait(0); 1413 vm_map_lock(&kernel_map); 1414 } 1415 i -= PAGE_SIZE; /* retry */ 1416 continue; 1417 } 1418 1419 /* 1420 * We were unable to recover, cleanup and return NULL 1421 * 1422 * (vm_token already held) 1423 */ 1424 while (i != 0) { 1425 i -= PAGE_SIZE; 1426 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i)); 1427 /* page should already be busy */ 1428 vm_page_free(m); 1429 } 1430 vm_map_delete(&kernel_map, addr, addr + size, &count); 1431 vm_map_unlock(&kernel_map); 1432 vm_map_entry_release(count); 1433 crit_exit(); 1434 lwkt_reltoken(&vm_token); 1435 return(NULL); 1436 } 1437 } 1438 1439 /* 1440 * Success! 1441 * 1442 * Mark the map entry as non-pageable using a routine that allows us to 1443 * populate the underlying pages. 1444 * 1445 * The pages were busied by the allocations above. 1446 */ 1447 vm_map_set_wired_quick(&kernel_map, addr, size, &count); 1448 crit_exit(); 1449 1450 /* 1451 * Enter the pages into the pmap and deal with PG_ZERO and M_ZERO. 1452 */ 1453 for (i = 0; i < size; i += PAGE_SIZE) { 1454 vm_page_t m; 1455 1456 if ((i / PAGE_SIZE) < (sizeof(mp) / sizeof(mp[0]))) 1457 m = mp[i / PAGE_SIZE]; 1458 else 1459 m = vm_page_lookup(&kernel_object, OFF_TO_IDX(addr + i)); 1460 m->valid = VM_PAGE_BITS_ALL; 1461 /* page should already be busy */ 1462 vm_page_wire(m); 1463 vm_page_wakeup(m); 1464 pmap_enter(&kernel_pmap, addr + i, m, VM_PROT_ALL, 1); 1465 if ((m->flags & PG_ZERO) == 0 && (flags & M_ZERO)) 1466 bzero((char *)addr + i, PAGE_SIZE); 1467 vm_page_flag_clear(m, PG_ZERO); 1468 KKASSERT(m->flags & (PG_WRITEABLE | PG_MAPPED)); 1469 vm_page_flag_set(m, PG_REFERENCED); 1470 } 1471 vm_map_unlock(&kernel_map); 1472 vm_map_entry_release(count); 1473 lwkt_reltoken(&vm_token); 1474 return((void *)addr); 1475 } 1476 1477 /* 1478 * kmem_slab_free() 1479 */ 1480 static void 1481 kmem_slab_free(void *ptr, vm_size_t size) 1482 { 1483 crit_enter(); 1484 lwkt_gettoken(&vm_token); 1485 vm_map_remove(&kernel_map, (vm_offset_t)ptr, (vm_offset_t)ptr + size); 1486 lwkt_reltoken(&vm_token); 1487 crit_exit(); 1488 } 1489 1490