1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved. 23 */ 24 25 /* 26 * Kernel memory allocator, as described in the following two papers and a 27 * statement about the consolidator: 28 * 29 * Jeff Bonwick, 30 * The Slab Allocator: An Object-Caching Kernel Memory Allocator. 31 * Proceedings of the Summer 1994 Usenix Conference. 32 * Available as /shared/sac/PSARC/1994/028/materials/kmem.pdf. 33 * 34 * Jeff Bonwick and Jonathan Adams, 35 * Magazines and vmem: Extending the Slab Allocator to Many CPUs and 36 * Arbitrary Resources. 37 * Proceedings of the 2001 Usenix Conference. 38 * Available as /shared/sac/PSARC/2000/550/materials/vmem.pdf. 39 * 40 * kmem Slab Consolidator Big Theory Statement: 41 * 42 * 1. Motivation 43 * 44 * As stated in Bonwick94, slabs provide the following advantages over other 45 * allocation structures in terms of memory fragmentation: 46 * 47 * - Internal fragmentation (per-buffer wasted space) is minimal. 48 * - Severe external fragmentation (unused buffers on the free list) is 49 * unlikely. 50 * 51 * Segregating objects by size eliminates one source of external fragmentation, 52 * and according to Bonwick: 53 * 54 * The other reason that slabs reduce external fragmentation is that all 55 * objects in a slab are of the same type, so they have the same lifetime 56 * distribution. The resulting segregation of short-lived and long-lived 57 * objects at slab granularity reduces the likelihood of an entire page being 58 * held hostage due to a single long-lived allocation [Barrett93, Hanson90]. 59 * 60 * While unlikely, severe external fragmentation remains possible. Clients that 61 * allocate both short- and long-lived objects from the same cache cannot 62 * anticipate the distribution of long-lived objects within the allocator's slab 63 * implementation. Even a small percentage of long-lived objects distributed 64 * randomly across many slabs can lead to a worst case scenario where the client 65 * frees the majority of its objects and the system gets back almost none of the 66 * slabs. Despite the client doing what it reasonably can to help the system 67 * reclaim memory, the allocator cannot shake free enough slabs because of 68 * lonely allocations stubbornly hanging on. Although the allocator is in a 69 * position to diagnose the fragmentation, there is nothing that the allocator 70 * by itself can do about it. It only takes a single allocated object to prevent 71 * an entire slab from being reclaimed, and any object handed out by 72 * kmem_cache_alloc() is by definition in the client's control. Conversely, 73 * although the client is in a position to move a long-lived object, it has no 74 * way of knowing if the object is causing fragmentation, and if so, where to 75 * move it. A solution necessarily requires further cooperation between the 76 * allocator and the client. 77 * 78 * 2. Move Callback 79 * 80 * The kmem slab consolidator therefore adds a move callback to the 81 * allocator/client interface, improving worst-case external fragmentation in 82 * kmem caches that supply a function to move objects from one memory location 83 * to another. In a situation of low memory kmem attempts to consolidate all of 84 * a cache's slabs at once; otherwise it works slowly to bring external 85 * fragmentation within the 1/8 limit guaranteed for internal fragmentation, 86 * thereby helping to avoid a low memory situation in the future. 87 * 88 * The callback has the following signature: 89 * 90 * kmem_cbrc_t move(void *old, void *new, size_t size, void *user_arg) 91 * 92 * It supplies the kmem client with two addresses: the allocated object that 93 * kmem wants to move and a buffer selected by kmem for the client to use as the 94 * copy destination. The callback is kmem's way of saying "Please get off of 95 * this buffer and use this one instead." kmem knows where it wants to move the 96 * object in order to best reduce fragmentation. All the client needs to know 97 * about the second argument (void *new) is that it is an allocated, constructed 98 * object ready to take the contents of the old object. When the move function 99 * is called, the system is likely to be low on memory, and the new object 100 * spares the client from having to worry about allocating memory for the 101 * requested move. The third argument supplies the size of the object, in case a 102 * single move function handles multiple caches whose objects differ only in 103 * size (such as zio_buf_512, zio_buf_1024, etc). Finally, the same optional 104 * user argument passed to the constructor, destructor, and reclaim functions is 105 * also passed to the move callback. 106 * 107 * 2.1 Setting the Move Callback 108 * 109 * The client sets the move callback after creating the cache and before 110 * allocating from it: 111 * 112 * object_cache = kmem_cache_create(...); 113 * kmem_cache_set_move(object_cache, object_move); 114 * 115 * 2.2 Move Callback Return Values 116 * 117 * Only the client knows about its own data and when is a good time to move it. 118 * The client is cooperating with kmem to return unused memory to the system, 119 * and kmem respectfully accepts this help at the client's convenience. When 120 * asked to move an object, the client can respond with any of the following: 121 * 122 * typedef enum kmem_cbrc { 123 * KMEM_CBRC_YES, 124 * KMEM_CBRC_NO, 125 * KMEM_CBRC_LATER, 126 * KMEM_CBRC_DONT_NEED, 127 * KMEM_CBRC_DONT_KNOW 128 * } kmem_cbrc_t; 129 * 130 * The client must not explicitly kmem_cache_free() either of the objects passed 131 * to the callback, since kmem wants to free them directly to the slab layer 132 * (bypassing the per-CPU magazine layer). The response tells kmem which of the 133 * objects to free: 134 * 135 * YES: (Did it) The client moved the object, so kmem frees the old one. 136 * NO: (Never) The client refused, so kmem frees the new object (the 137 * unused copy destination). kmem also marks the slab of the old 138 * object so as not to bother the client with further callbacks for 139 * that object as long as the slab remains on the partial slab list. 140 * (The system won't be getting the slab back as long as the 141 * immovable object holds it hostage, so there's no point in moving 142 * any of its objects.) 143 * LATER: The client is using the object and cannot move it now, so kmem 144 * frees the new object (the unused copy destination). kmem still 145 * attempts to move other objects off the slab, since it expects to 146 * succeed in clearing the slab in a later callback. The client 147 * should use LATER instead of NO if the object is likely to become 148 * movable very soon. 149 * DONT_NEED: The client no longer needs the object, so kmem frees the old along 150 * with the new object (the unused copy destination). This response 151 * is the client's opportunity to be a model citizen and give back as 152 * much as it can. 153 * DONT_KNOW: The client does not know about the object because 154 * a) the client has just allocated the object and not yet put it 155 * wherever it expects to find known objects 156 * b) the client has removed the object from wherever it expects to 157 * find known objects and is about to free it, or 158 * c) the client has freed the object. 159 * In all these cases (a, b, and c) kmem frees the new object (the 160 * unused copy destination) and searches for the old object in the 161 * magazine layer. If found, the object is removed from the magazine 162 * layer and freed to the slab layer so it will no longer hold the 163 * slab hostage. 164 * 165 * 2.3 Object States 166 * 167 * Neither kmem nor the client can be assumed to know the object's whereabouts 168 * at the time of the callback. An object belonging to a kmem cache may be in 169 * any of the following states: 170 * 171 * 1. Uninitialized on the slab 172 * 2. Allocated from the slab but not constructed (still uninitialized) 173 * 3. Allocated from the slab, constructed, but not yet ready for business 174 * (not in a valid state for the move callback) 175 * 4. In use (valid and known to the client) 176 * 5. About to be freed (no longer in a valid state for the move callback) 177 * 6. Freed to a magazine (still constructed) 178 * 7. Allocated from a magazine, not yet ready for business (not in a valid 179 * state for the move callback), and about to return to state #4 180 * 8. Deconstructed on a magazine that is about to be freed 181 * 9. Freed to the slab 182 * 183 * Since the move callback may be called at any time while the object is in any 184 * of the above states (except state #1), the client needs a safe way to 185 * determine whether or not it knows about the object. Specifically, the client 186 * needs to know whether or not the object is in state #4, the only state in 187 * which a move is valid. If the object is in any other state, the client should 188 * immediately return KMEM_CBRC_DONT_KNOW, since it is unsafe to access any of 189 * the object's fields. 190 * 191 * Note that although an object may be in state #4 when kmem initiates the move 192 * request, the object may no longer be in that state by the time kmem actually 193 * calls the move function. Not only does the client free objects 194 * asynchronously, kmem itself puts move requests on a queue where thay are 195 * pending until kmem processes them from another context. Also, objects freed 196 * to a magazine appear allocated from the point of view of the slab layer, so 197 * kmem may even initiate requests for objects in a state other than state #4. 198 * 199 * 2.3.1 Magazine Layer 200 * 201 * An important insight revealed by the states listed above is that the magazine 202 * layer is populated only by kmem_cache_free(). Magazines of constructed 203 * objects are never populated directly from the slab layer (which contains raw, 204 * unconstructed objects). Whenever an allocation request cannot be satisfied 205 * from the magazine layer, the magazines are bypassed and the request is 206 * satisfied from the slab layer (creating a new slab if necessary). kmem calls 207 * the object constructor only when allocating from the slab layer, and only in 208 * response to kmem_cache_alloc() or to prepare the destination buffer passed in 209 * the move callback. kmem does not preconstruct objects in anticipation of 210 * kmem_cache_alloc(). 211 * 212 * 2.3.2 Object Constructor and Destructor 213 * 214 * If the client supplies a destructor, it must be valid to call the destructor 215 * on a newly created object (immediately after the constructor). 216 * 217 * 2.4 Recognizing Known Objects 218 * 219 * There is a simple test to determine safely whether or not the client knows 220 * about a given object in the move callback. It relies on the fact that kmem 221 * guarantees that the object of the move callback has only been touched by the 222 * client itself or else by kmem. kmem does this by ensuring that none of the 223 * cache's slabs are freed to the virtual memory (VM) subsystem while a move 224 * callback is pending. When the last object on a slab is freed, if there is a 225 * pending move, kmem puts the slab on a per-cache dead list and defers freeing 226 * slabs on that list until all pending callbacks are completed. That way, 227 * clients can be certain that the object of a move callback is in one of the 228 * states listed above, making it possible to distinguish known objects (in 229 * state #4) using the two low order bits of any pointer member (with the 230 * exception of 'char *' or 'short *' which may not be 4-byte aligned on some 231 * platforms). 232 * 233 * The test works as long as the client always transitions objects from state #4 234 * (known, in use) to state #5 (about to be freed, invalid) by setting the low 235 * order bit of the client-designated pointer member. Since kmem only writes 236 * invalid memory patterns, such as 0xbaddcafe to uninitialized memory and 237 * 0xdeadbeef to freed memory, any scribbling on the object done by kmem is 238 * guaranteed to set at least one of the two low order bits. Therefore, given an 239 * object with a back pointer to a 'container_t *o_container', the client can 240 * test 241 * 242 * container_t *container = object->o_container; 243 * if ((uintptr_t)container & 0x3) { 244 * return (KMEM_CBRC_DONT_KNOW); 245 * } 246 * 247 * Typically, an object will have a pointer to some structure with a list or 248 * hash where objects from the cache are kept while in use. Assuming that the 249 * client has some way of knowing that the container structure is valid and will 250 * not go away during the move, and assuming that the structure includes a lock 251 * to protect whatever collection is used, then the client would continue as 252 * follows: 253 * 254 * // Ensure that the container structure does not go away. 255 * if (container_hold(container) == 0) { 256 * return (KMEM_CBRC_DONT_KNOW); 257 * } 258 * mutex_enter(&container->c_objects_lock); 259 * if (container != object->o_container) { 260 * mutex_exit(&container->c_objects_lock); 261 * container_rele(container); 262 * return (KMEM_CBRC_DONT_KNOW); 263 * } 264 * 265 * At this point the client knows that the object cannot be freed as long as 266 * c_objects_lock is held. Note that after acquiring the lock, the client must 267 * recheck the o_container pointer in case the object was removed just before 268 * acquiring the lock. 269 * 270 * When the client is about to free an object, it must first remove that object 271 * from the list, hash, or other structure where it is kept. At that time, to 272 * mark the object so it can be distinguished from the remaining, known objects, 273 * the client sets the designated low order bit: 274 * 275 * mutex_enter(&container->c_objects_lock); 276 * object->o_container = (void *)((uintptr_t)object->o_container | 0x1); 277 * list_remove(&container->c_objects, object); 278 * mutex_exit(&container->c_objects_lock); 279 * 280 * In the common case, the object is freed to the magazine layer, where it may 281 * be reused on a subsequent allocation without the overhead of calling the 282 * constructor. While in the magazine it appears allocated from the point of 283 * view of the slab layer, making it a candidate for the move callback. Most 284 * objects unrecognized by the client in the move callback fall into this 285 * category and are cheaply distinguished from known objects by the test 286 * described earlier. Since recognition is cheap for the client, and searching 287 * magazines is expensive for kmem, kmem defers searching until the client first 288 * returns KMEM_CBRC_DONT_KNOW. As long as the needed effort is reasonable, kmem 289 * elsewhere does what it can to avoid bothering the client unnecessarily. 290 * 291 * Invalidating the designated pointer member before freeing the object marks 292 * the object to be avoided in the callback, and conversely, assigning a valid 293 * value to the designated pointer member after allocating the object makes the 294 * object fair game for the callback: 295 * 296 * ... allocate object ... 297 * ... set any initial state not set by the constructor ... 298 * 299 * mutex_enter(&container->c_objects_lock); 300 * list_insert_tail(&container->c_objects, object); 301 * membar_producer(); 302 * object->o_container = container; 303 * mutex_exit(&container->c_objects_lock); 304 * 305 * Note that everything else must be valid before setting o_container makes the 306 * object fair game for the move callback. The membar_producer() call ensures 307 * that all the object's state is written to memory before setting the pointer 308 * that transitions the object from state #3 or #7 (allocated, constructed, not 309 * yet in use) to state #4 (in use, valid). That's important because the move 310 * function has to check the validity of the pointer before it can safely 311 * acquire the lock protecting the collection where it expects to find known 312 * objects. 313 * 314 * This method of distinguishing known objects observes the usual symmetry: 315 * invalidating the designated pointer is the first thing the client does before 316 * freeing the object, and setting the designated pointer is the last thing the 317 * client does after allocating the object. Of course, the client is not 318 * required to use this method. Fundamentally, how the client recognizes known 319 * objects is completely up to the client, but this method is recommended as an 320 * efficient and safe way to take advantage of the guarantees made by kmem. If 321 * the entire object is arbitrary data without any markable bits from a suitable 322 * pointer member, then the client must find some other method, such as 323 * searching a hash table of known objects. 324 * 325 * 2.5 Preventing Objects From Moving 326 * 327 * Besides a way to distinguish known objects, the other thing that the client 328 * needs is a strategy to ensure that an object will not move while the client 329 * is actively using it. The details of satisfying this requirement tend to be 330 * highly cache-specific. It might seem that the same rules that let a client 331 * remove an object safely should also decide when an object can be moved 332 * safely. However, any object state that makes a removal attempt invalid is 333 * likely to be long-lasting for objects that the client does not expect to 334 * remove. kmem knows nothing about the object state and is equally likely (from 335 * the client's point of view) to request a move for any object in the cache, 336 * whether prepared for removal or not. Even a low percentage of objects stuck 337 * in place by unremovability will defeat the consolidator if the stuck objects 338 * are the same long-lived allocations likely to hold slabs hostage. 339 * Fundamentally, the consolidator is not aimed at common cases. Severe external 340 * fragmentation is a worst case scenario manifested as sparsely allocated 341 * slabs, by definition a low percentage of the cache's objects. When deciding 342 * what makes an object movable, keep in mind the goal of the consolidator: to 343 * bring worst-case external fragmentation within the limits guaranteed for 344 * internal fragmentation. Removability is a poor criterion if it is likely to 345 * exclude more than an insignificant percentage of objects for long periods of 346 * time. 347 * 348 * A tricky general solution exists, and it has the advantage of letting you 349 * move any object at almost any moment, practically eliminating the likelihood 350 * that an object can hold a slab hostage. However, if there is a cache-specific 351 * way to ensure that an object is not actively in use in the vast majority of 352 * cases, a simpler solution that leverages this cache-specific knowledge is 353 * preferred. 354 * 355 * 2.5.1 Cache-Specific Solution 356 * 357 * As an example of a cache-specific solution, the ZFS znode cache takes 358 * advantage of the fact that the vast majority of znodes are only being 359 * referenced from the DNLC. (A typical case might be a few hundred in active 360 * use and a hundred thousand in the DNLC.) In the move callback, after the ZFS 361 * client has established that it recognizes the znode and can access its fields 362 * safely (using the method described earlier), it then tests whether the znode 363 * is referenced by anything other than the DNLC. If so, it assumes that the 364 * znode may be in active use and is unsafe to move, so it drops its locks and 365 * returns KMEM_CBRC_LATER. The advantage of this strategy is that everywhere 366 * else znodes are used, no change is needed to protect against the possibility 367 * of the znode moving. The disadvantage is that it remains possible for an 368 * application to hold a znode slab hostage with an open file descriptor. 369 * However, this case ought to be rare and the consolidator has a way to deal 370 * with it: If the client responds KMEM_CBRC_LATER repeatedly for the same 371 * object, kmem eventually stops believing it and treats the slab as if the 372 * client had responded KMEM_CBRC_NO. Having marked the hostage slab, kmem can 373 * then focus on getting it off of the partial slab list by allocating rather 374 * than freeing all of its objects. (Either way of getting a slab off the 375 * free list reduces fragmentation.) 376 * 377 * 2.5.2 General Solution 378 * 379 * The general solution, on the other hand, requires an explicit hold everywhere 380 * the object is used to prevent it from moving. To keep the client locking 381 * strategy as uncomplicated as possible, kmem guarantees the simplifying 382 * assumption that move callbacks are sequential, even across multiple caches. 383 * Internally, a global queue processed by a single thread supports all caches 384 * implementing the callback function. No matter how many caches supply a move 385 * function, the consolidator never moves more than one object at a time, so the 386 * client does not have to worry about tricky lock ordering involving several 387 * related objects from different kmem caches. 388 * 389 * The general solution implements the explicit hold as a read-write lock, which 390 * allows multiple readers to access an object from the cache simultaneously 391 * while a single writer is excluded from moving it. A single rwlock for the 392 * entire cache would lock out all threads from using any of the cache's objects 393 * even though only a single object is being moved, so to reduce contention, 394 * the client can fan out the single rwlock into an array of rwlocks hashed by 395 * the object address, making it probable that moving one object will not 396 * prevent other threads from using a different object. The rwlock cannot be a 397 * member of the object itself, because the possibility of the object moving 398 * makes it unsafe to access any of the object's fields until the lock is 399 * acquired. 400 * 401 * Assuming a small, fixed number of locks, it's possible that multiple objects 402 * will hash to the same lock. A thread that needs to use multiple objects in 403 * the same function may acquire the same lock multiple times. Since rwlocks are 404 * reentrant for readers, and since there is never more than a single writer at 405 * a time (assuming that the client acquires the lock as a writer only when 406 * moving an object inside the callback), there would seem to be no problem. 407 * However, a client locking multiple objects in the same function must handle 408 * one case of potential deadlock: Assume that thread A needs to prevent both 409 * object 1 and object 2 from moving, and thread B, the callback, meanwhile 410 * tries to move object 3. It's possible, if objects 1, 2, and 3 all hash to the 411 * same lock, that thread A will acquire the lock for object 1 as a reader 412 * before thread B sets the lock's write-wanted bit, preventing thread A from 413 * reacquiring the lock for object 2 as a reader. Unable to make forward 414 * progress, thread A will never release the lock for object 1, resulting in 415 * deadlock. 416 * 417 * There are two ways of avoiding the deadlock just described. The first is to 418 * use rw_tryenter() rather than rw_enter() in the callback function when 419 * attempting to acquire the lock as a writer. If tryenter discovers that the 420 * same object (or another object hashed to the same lock) is already in use, it 421 * aborts the callback and returns KMEM_CBRC_LATER. The second way is to use 422 * rprwlock_t (declared in common/fs/zfs/sys/rprwlock.h) instead of rwlock_t, 423 * since it allows a thread to acquire the lock as a reader in spite of a 424 * waiting writer. This second approach insists on moving the object now, no 425 * matter how many readers the move function must wait for in order to do so, 426 * and could delay the completion of the callback indefinitely (blocking 427 * callbacks to other clients). In practice, a less insistent callback using 428 * rw_tryenter() returns KMEM_CBRC_LATER infrequently enough that there seems 429 * little reason to use anything else. 430 * 431 * Avoiding deadlock is not the only problem that an implementation using an 432 * explicit hold needs to solve. Locking the object in the first place (to 433 * prevent it from moving) remains a problem, since the object could move 434 * between the time you obtain a pointer to the object and the time you acquire 435 * the rwlock hashed to that pointer value. Therefore the client needs to 436 * recheck the value of the pointer after acquiring the lock, drop the lock if 437 * the value has changed, and try again. This requires a level of indirection: 438 * something that points to the object rather than the object itself, that the 439 * client can access safely while attempting to acquire the lock. (The object 440 * itself cannot be referenced safely because it can move at any time.) 441 * The following lock-acquisition function takes whatever is safe to reference 442 * (arg), follows its pointer to the object (using function f), and tries as 443 * often as necessary to acquire the hashed lock and verify that the object 444 * still has not moved: 445 * 446 * object_t * 447 * object_hold(object_f f, void *arg) 448 * { 449 * object_t *op; 450 * 451 * op = f(arg); 452 * if (op == NULL) { 453 * return (NULL); 454 * } 455 * 456 * rw_enter(OBJECT_RWLOCK(op), RW_READER); 457 * while (op != f(arg)) { 458 * rw_exit(OBJECT_RWLOCK(op)); 459 * op = f(arg); 460 * if (op == NULL) { 461 * break; 462 * } 463 * rw_enter(OBJECT_RWLOCK(op), RW_READER); 464 * } 465 * 466 * return (op); 467 * } 468 * 469 * The OBJECT_RWLOCK macro hashes the object address to obtain the rwlock. The 470 * lock reacquisition loop, while necessary, almost never executes. The function 471 * pointer f (used to obtain the object pointer from arg) has the following type 472 * definition: 473 * 474 * typedef object_t *(*object_f)(void *arg); 475 * 476 * An object_f implementation is likely to be as simple as accessing a structure 477 * member: 478 * 479 * object_t * 480 * s_object(void *arg) 481 * { 482 * something_t *sp = arg; 483 * return (sp->s_object); 484 * } 485 * 486 * The flexibility of a function pointer allows the path to the object to be 487 * arbitrarily complex and also supports the notion that depending on where you 488 * are using the object, you may need to get it from someplace different. 489 * 490 * The function that releases the explicit hold is simpler because it does not 491 * have to worry about the object moving: 492 * 493 * void 494 * object_rele(object_t *op) 495 * { 496 * rw_exit(OBJECT_RWLOCK(op)); 497 * } 498 * 499 * The caller is spared these details so that obtaining and releasing an 500 * explicit hold feels like a simple mutex_enter()/mutex_exit() pair. The caller 501 * of object_hold() only needs to know that the returned object pointer is valid 502 * if not NULL and that the object will not move until released. 503 * 504 * Although object_hold() prevents an object from moving, it does not prevent it 505 * from being freed. The caller must take measures before calling object_hold() 506 * (afterwards is too late) to ensure that the held object cannot be freed. The 507 * caller must do so without accessing the unsafe object reference, so any lock 508 * or reference count used to ensure the continued existence of the object must 509 * live outside the object itself. 510 * 511 * Obtaining a new object is a special case where an explicit hold is impossible 512 * for the caller. Any function that returns a newly allocated object (either as 513 * a return value, or as an in-out paramter) must return it already held; after 514 * the caller gets it is too late, since the object cannot be safely accessed 515 * without the level of indirection described earlier. The following 516 * object_alloc() example uses the same code shown earlier to transition a new 517 * object into the state of being recognized (by the client) as a known object. 518 * The function must acquire the hold (rw_enter) before that state transition 519 * makes the object movable: 520 * 521 * static object_t * 522 * object_alloc(container_t *container) 523 * { 524 * object_t *object = kmem_cache_alloc(object_cache, 0); 525 * ... set any initial state not set by the constructor ... 526 * rw_enter(OBJECT_RWLOCK(object), RW_READER); 527 * mutex_enter(&container->c_objects_lock); 528 * list_insert_tail(&container->c_objects, object); 529 * membar_producer(); 530 * object->o_container = container; 531 * mutex_exit(&container->c_objects_lock); 532 * return (object); 533 * } 534 * 535 * Functions that implicitly acquire an object hold (any function that calls 536 * object_alloc() to supply an object for the caller) need to be carefully noted 537 * so that the matching object_rele() is not neglected. Otherwise, leaked holds 538 * prevent all objects hashed to the affected rwlocks from ever being moved. 539 * 540 * The pointer to a held object can be hashed to the holding rwlock even after 541 * the object has been freed. Although it is possible to release the hold 542 * after freeing the object, you may decide to release the hold implicitly in 543 * whatever function frees the object, so as to release the hold as soon as 544 * possible, and for the sake of symmetry with the function that implicitly 545 * acquires the hold when it allocates the object. Here, object_free() releases 546 * the hold acquired by object_alloc(). Its implicit object_rele() forms a 547 * matching pair with object_hold(): 548 * 549 * void 550 * object_free(object_t *object) 551 * { 552 * container_t *container; 553 * 554 * ASSERT(object_held(object)); 555 * container = object->o_container; 556 * mutex_enter(&container->c_objects_lock); 557 * object->o_container = 558 * (void *)((uintptr_t)object->o_container | 0x1); 559 * list_remove(&container->c_objects, object); 560 * mutex_exit(&container->c_objects_lock); 561 * object_rele(object); 562 * kmem_cache_free(object_cache, object); 563 * } 564 * 565 * Note that object_free() cannot safely accept an object pointer as an argument 566 * unless the object is already held. Any function that calls object_free() 567 * needs to be carefully noted since it similarly forms a matching pair with 568 * object_hold(). 569 * 570 * To complete the picture, the following callback function implements the 571 * general solution by moving objects only if they are currently unheld: 572 * 573 * static kmem_cbrc_t 574 * object_move(void *buf, void *newbuf, size_t size, void *arg) 575 * { 576 * object_t *op = buf, *np = newbuf; 577 * container_t *container; 578 * 579 * container = op->o_container; 580 * if ((uintptr_t)container & 0x3) { 581 * return (KMEM_CBRC_DONT_KNOW); 582 * } 583 * 584 * // Ensure that the container structure does not go away. 585 * if (container_hold(container) == 0) { 586 * return (KMEM_CBRC_DONT_KNOW); 587 * } 588 * 589 * mutex_enter(&container->c_objects_lock); 590 * if (container != op->o_container) { 591 * mutex_exit(&container->c_objects_lock); 592 * container_rele(container); 593 * return (KMEM_CBRC_DONT_KNOW); 594 * } 595 * 596 * if (rw_tryenter(OBJECT_RWLOCK(op), RW_WRITER) == 0) { 597 * mutex_exit(&container->c_objects_lock); 598 * container_rele(container); 599 * return (KMEM_CBRC_LATER); 600 * } 601 * 602 * object_move_impl(op, np); // critical section 603 * rw_exit(OBJECT_RWLOCK(op)); 604 * 605 * op->o_container = (void *)((uintptr_t)op->o_container | 0x1); 606 * list_link_replace(&op->o_link_node, &np->o_link_node); 607 * mutex_exit(&container->c_objects_lock); 608 * container_rele(container); 609 * return (KMEM_CBRC_YES); 610 * } 611 * 612 * Note that object_move() must invalidate the designated o_container pointer of 613 * the old object in the same way that object_free() does, since kmem will free 614 * the object in response to the KMEM_CBRC_YES return value. 615 * 616 * The lock order in object_move() differs from object_alloc(), which locks 617 * OBJECT_RWLOCK first and &container->c_objects_lock second, but as long as the 618 * callback uses rw_tryenter() (preventing the deadlock described earlier), it's 619 * not a problem. Holding the lock on the object list in the example above 620 * through the entire callback not only prevents the object from going away, it 621 * also allows you to lock the list elsewhere and know that none of its elements 622 * will move during iteration. 623 * 624 * Adding an explicit hold everywhere an object from the cache is used is tricky 625 * and involves much more change to client code than a cache-specific solution 626 * that leverages existing state to decide whether or not an object is 627 * movable. However, this approach has the advantage that no object remains 628 * immovable for any significant length of time, making it extremely unlikely 629 * that long-lived allocations can continue holding slabs hostage; and it works 630 * for any cache. 631 * 632 * 3. Consolidator Implementation 633 * 634 * Once the client supplies a move function that a) recognizes known objects and 635 * b) avoids moving objects that are actively in use, the remaining work is up 636 * to the consolidator to decide which objects to move and when to issue 637 * callbacks. 638 * 639 * The consolidator relies on the fact that a cache's slabs are ordered by 640 * usage. Each slab has a fixed number of objects. Depending on the slab's 641 * "color" (the offset of the first object from the beginning of the slab; 642 * offsets are staggered to mitigate false sharing of cache lines) it is either 643 * the maximum number of objects per slab determined at cache creation time or 644 * else the number closest to the maximum that fits within the space remaining 645 * after the initial offset. A completely allocated slab may contribute some 646 * internal fragmentation (per-slab overhead) but no external fragmentation, so 647 * it is of no interest to the consolidator. At the other extreme, slabs whose 648 * objects have all been freed to the slab are released to the virtual memory 649 * (VM) subsystem (objects freed to magazines are still allocated as far as the 650 * slab is concerned). External fragmentation exists when there are slabs 651 * somewhere between these extremes. A partial slab has at least one but not all 652 * of its objects allocated. The more partial slabs, and the fewer allocated 653 * objects on each of them, the higher the fragmentation. Hence the 654 * consolidator's overall strategy is to reduce the number of partial slabs by 655 * moving allocated objects from the least allocated slabs to the most allocated 656 * slabs. 657 * 658 * Partial slabs are kept in an AVL tree ordered by usage. Completely allocated 659 * slabs are kept separately in an unordered list. Since the majority of slabs 660 * tend to be completely allocated (a typical unfragmented cache may have 661 * thousands of complete slabs and only a single partial slab), separating 662 * complete slabs improves the efficiency of partial slab ordering, since the 663 * complete slabs do not affect the depth or balance of the AVL tree. This 664 * ordered sequence of partial slabs acts as a "free list" supplying objects for 665 * allocation requests. 666 * 667 * Objects are always allocated from the first partial slab in the free list, 668 * where the allocation is most likely to eliminate a partial slab (by 669 * completely allocating it). Conversely, when a single object from a completely 670 * allocated slab is freed to the slab, that slab is added to the front of the 671 * free list. Since most free list activity involves highly allocated slabs 672 * coming and going at the front of the list, slabs tend naturally toward the 673 * ideal order: highly allocated at the front, sparsely allocated at the back. 674 * Slabs with few allocated objects are likely to become completely free if they 675 * keep a safe distance away from the front of the free list. Slab misorders 676 * interfere with the natural tendency of slabs to become completely free or 677 * completely allocated. For example, a slab with a single allocated object 678 * needs only a single free to escape the cache; its natural desire is 679 * frustrated when it finds itself at the front of the list where a second 680 * allocation happens just before the free could have released it. Another slab 681 * with all but one object allocated might have supplied the buffer instead, so 682 * that both (as opposed to neither) of the slabs would have been taken off the 683 * free list. 684 * 685 * Although slabs tend naturally toward the ideal order, misorders allowed by a 686 * simple list implementation defeat the consolidator's strategy of merging 687 * least- and most-allocated slabs. Without an AVL tree to guarantee order, kmem 688 * needs another way to fix misorders to optimize its callback strategy. One 689 * approach is to periodically scan a limited number of slabs, advancing a 690 * marker to hold the current scan position, and to move extreme misorders to 691 * the front or back of the free list and to the front or back of the current 692 * scan range. By making consecutive scan ranges overlap by one slab, the least 693 * allocated slab in the current range can be carried along from the end of one 694 * scan to the start of the next. 695 * 696 * Maintaining partial slabs in an AVL tree relieves kmem of this additional 697 * task, however. Since most of the cache's activity is in the magazine layer, 698 * and allocations from the slab layer represent only a startup cost, the 699 * overhead of maintaining a balanced tree is not a significant concern compared 700 * to the opportunity of reducing complexity by eliminating the partial slab 701 * scanner just described. The overhead of an AVL tree is minimized by 702 * maintaining only partial slabs in the tree and keeping completely allocated 703 * slabs separately in a list. To avoid increasing the size of the slab 704 * structure the AVL linkage pointers are reused for the slab's list linkage, 705 * since the slab will always be either partial or complete, never stored both 706 * ways at the same time. To further minimize the overhead of the AVL tree the 707 * compare function that orders partial slabs by usage divides the range of 708 * allocated object counts into bins such that counts within the same bin are 709 * considered equal. Binning partial slabs makes it less likely that allocating 710 * or freeing a single object will change the slab's order, requiring a tree 711 * reinsertion (an avl_remove() followed by an avl_add(), both potentially 712 * requiring some rebalancing of the tree). Allocation counts closest to 713 * completely free and completely allocated are left unbinned (finely sorted) to 714 * better support the consolidator's strategy of merging slabs at either 715 * extreme. 716 * 717 * 3.1 Assessing Fragmentation and Selecting Candidate Slabs 718 * 719 * The consolidator piggybacks on the kmem maintenance thread and is called on 720 * the same interval as kmem_cache_update(), once per cache every fifteen 721 * seconds. kmem maintains a running count of unallocated objects in the slab 722 * layer (cache_bufslab). The consolidator checks whether that number exceeds 723 * 12.5% (1/8) of the total objects in the cache (cache_buftotal), and whether 724 * there is a significant number of slabs in the cache (arbitrarily a minimum 725 * 101 total slabs). Unused objects that have fallen out of the magazine layer's 726 * working set are included in the assessment, and magazines in the depot are 727 * reaped if those objects would lift cache_bufslab above the fragmentation 728 * threshold. Once the consolidator decides that a cache is fragmented, it looks 729 * for a candidate slab to reclaim, starting at the end of the partial slab free 730 * list and scanning backwards. At first the consolidator is choosy: only a slab 731 * with fewer than 12.5% (1/8) of its objects allocated qualifies (or else a 732 * single allocated object, regardless of percentage). If there is difficulty 733 * finding a candidate slab, kmem raises the allocation threshold incrementally, 734 * up to a maximum 87.5% (7/8), so that eventually the consolidator will reduce 735 * external fragmentation (unused objects on the free list) below 12.5% (1/8), 736 * even in the worst case of every slab in the cache being almost 7/8 allocated. 737 * The threshold can also be lowered incrementally when candidate slabs are easy 738 * to find, and the threshold is reset to the minimum 1/8 as soon as the cache 739 * is no longer fragmented. 740 * 741 * 3.2 Generating Callbacks 742 * 743 * Once an eligible slab is chosen, a callback is generated for every allocated 744 * object on the slab, in the hope that the client will move everything off the 745 * slab and make it reclaimable. Objects selected as move destinations are 746 * chosen from slabs at the front of the free list. Assuming slabs in the ideal 747 * order (most allocated at the front, least allocated at the back) and a 748 * cooperative client, the consolidator will succeed in removing slabs from both 749 * ends of the free list, completely allocating on the one hand and completely 750 * freeing on the other. Objects selected as move destinations are allocated in 751 * the kmem maintenance thread where move requests are enqueued. A separate 752 * callback thread removes pending callbacks from the queue and calls the 753 * client. The separate thread ensures that client code (the move function) does 754 * not interfere with internal kmem maintenance tasks. A map of pending 755 * callbacks keyed by object address (the object to be moved) is checked to 756 * ensure that duplicate callbacks are not generated for the same object. 757 * Allocating the move destination (the object to move to) prevents subsequent 758 * callbacks from selecting the same destination as an earlier pending callback. 759 * 760 * Move requests can also be generated by kmem_cache_reap() when the system is 761 * desperate for memory and by kmem_cache_move_notify(), called by the client to 762 * notify kmem that a move refused earlier with KMEM_CBRC_LATER is now possible. 763 * The map of pending callbacks is protected by the same lock that protects the 764 * slab layer. 765 * 766 * When the system is desperate for memory, kmem does not bother to determine 767 * whether or not the cache exceeds the fragmentation threshold, but tries to 768 * consolidate as many slabs as possible. Normally, the consolidator chews 769 * slowly, one sparsely allocated slab at a time during each maintenance 770 * interval that the cache is fragmented. When desperate, the consolidator 771 * starts at the last partial slab and enqueues callbacks for every allocated 772 * object on every partial slab, working backwards until it reaches the first 773 * partial slab. The first partial slab, meanwhile, advances in pace with the 774 * consolidator as allocations to supply move destinations for the enqueued 775 * callbacks use up the highly allocated slabs at the front of the free list. 776 * Ideally, the overgrown free list collapses like an accordion, starting at 777 * both ends and ending at the center with a single partial slab. 778 * 779 * 3.3 Client Responses 780 * 781 * When the client returns KMEM_CBRC_NO in response to the move callback, kmem 782 * marks the slab that supplied the stuck object non-reclaimable and moves it to 783 * front of the free list. The slab remains marked as long as it remains on the 784 * free list, and it appears more allocated to the partial slab compare function 785 * than any unmarked slab, no matter how many of its objects are allocated. 786 * Since even one immovable object ties up the entire slab, the goal is to 787 * completely allocate any slab that cannot be completely freed. kmem does not 788 * bother generating callbacks to move objects from a marked slab unless the 789 * system is desperate. 790 * 791 * When the client responds KMEM_CBRC_LATER, kmem increments a count for the 792 * slab. If the client responds LATER too many times, kmem disbelieves and 793 * treats the response as a NO. The count is cleared when the slab is taken off 794 * the partial slab list or when the client moves one of the slab's objects. 795 * 796 * 4. Observability 797 * 798 * A kmem cache's external fragmentation is best observed with 'mdb -k' using 799 * the ::kmem_slabs dcmd. For a complete description of the command, enter 800 * '::help kmem_slabs' at the mdb prompt. 801 */ 802 803 #include <sys/kmem_impl.h> 804 #include <sys/vmem_impl.h> 805 #include <sys/param.h> 806 #include <sys/sysmacros.h> 807 #include <sys/vm.h> 808 #include <sys/proc.h> 809 #include <sys/tuneable.h> 810 #include <sys/systm.h> 811 #include <sys/cmn_err.h> 812 #include <sys/debug.h> 813 #include <sys/sdt.h> 814 #include <sys/mutex.h> 815 #include <sys/bitmap.h> 816 #include <sys/atomic.h> 817 #include <sys/kobj.h> 818 #include <sys/disp.h> 819 #include <vm/seg_kmem.h> 820 #include <sys/log.h> 821 #include <sys/callb.h> 822 #include <sys/taskq.h> 823 #include <sys/modctl.h> 824 #include <sys/reboot.h> 825 #include <sys/id32.h> 826 #include <sys/zone.h> 827 #include <sys/netstack.h> 828 #ifdef DEBUG 829 #include <sys/random.h> 830 #endif 831 832 extern void streams_msg_init(void); 833 extern int segkp_fromheap; 834 extern void segkp_cache_free(void); 835 extern int callout_init_done; 836 837 struct kmem_cache_kstat { 838 kstat_named_t kmc_buf_size; 839 kstat_named_t kmc_align; 840 kstat_named_t kmc_chunk_size; 841 kstat_named_t kmc_slab_size; 842 kstat_named_t kmc_alloc; 843 kstat_named_t kmc_alloc_fail; 844 kstat_named_t kmc_free; 845 kstat_named_t kmc_depot_alloc; 846 kstat_named_t kmc_depot_free; 847 kstat_named_t kmc_depot_contention; 848 kstat_named_t kmc_slab_alloc; 849 kstat_named_t kmc_slab_free; 850 kstat_named_t kmc_buf_constructed; 851 kstat_named_t kmc_buf_avail; 852 kstat_named_t kmc_buf_inuse; 853 kstat_named_t kmc_buf_total; 854 kstat_named_t kmc_buf_max; 855 kstat_named_t kmc_slab_create; 856 kstat_named_t kmc_slab_destroy; 857 kstat_named_t kmc_vmem_source; 858 kstat_named_t kmc_hash_size; 859 kstat_named_t kmc_hash_lookup_depth; 860 kstat_named_t kmc_hash_rescale; 861 kstat_named_t kmc_full_magazines; 862 kstat_named_t kmc_empty_magazines; 863 kstat_named_t kmc_magazine_size; 864 kstat_named_t kmc_reap; /* number of kmem_cache_reap() calls */ 865 kstat_named_t kmc_defrag; /* attempts to defrag all partial slabs */ 866 kstat_named_t kmc_scan; /* attempts to defrag one partial slab */ 867 kstat_named_t kmc_move_callbacks; /* sum of yes, no, later, dn, dk */ 868 kstat_named_t kmc_move_yes; 869 kstat_named_t kmc_move_no; 870 kstat_named_t kmc_move_later; 871 kstat_named_t kmc_move_dont_need; 872 kstat_named_t kmc_move_dont_know; /* obj unrecognized by client ... */ 873 kstat_named_t kmc_move_hunt_found; /* ... but found in mag layer */ 874 kstat_named_t kmc_move_slabs_freed; /* slabs freed by consolidator */ 875 kstat_named_t kmc_move_reclaimable; /* buffers, if consolidator ran */ 876 } kmem_cache_kstat = { 877 { "buf_size", KSTAT_DATA_UINT64 }, 878 { "align", KSTAT_DATA_UINT64 }, 879 { "chunk_size", KSTAT_DATA_UINT64 }, 880 { "slab_size", KSTAT_DATA_UINT64 }, 881 { "alloc", KSTAT_DATA_UINT64 }, 882 { "alloc_fail", KSTAT_DATA_UINT64 }, 883 { "free", KSTAT_DATA_UINT64 }, 884 { "depot_alloc", KSTAT_DATA_UINT64 }, 885 { "depot_free", KSTAT_DATA_UINT64 }, 886 { "depot_contention", KSTAT_DATA_UINT64 }, 887 { "slab_alloc", KSTAT_DATA_UINT64 }, 888 { "slab_free", KSTAT_DATA_UINT64 }, 889 { "buf_constructed", KSTAT_DATA_UINT64 }, 890 { "buf_avail", KSTAT_DATA_UINT64 }, 891 { "buf_inuse", KSTAT_DATA_UINT64 }, 892 { "buf_total", KSTAT_DATA_UINT64 }, 893 { "buf_max", KSTAT_DATA_UINT64 }, 894 { "slab_create", KSTAT_DATA_UINT64 }, 895 { "slab_destroy", KSTAT_DATA_UINT64 }, 896 { "vmem_source", KSTAT_DATA_UINT64 }, 897 { "hash_size", KSTAT_DATA_UINT64 }, 898 { "hash_lookup_depth", KSTAT_DATA_UINT64 }, 899 { "hash_rescale", KSTAT_DATA_UINT64 }, 900 { "full_magazines", KSTAT_DATA_UINT64 }, 901 { "empty_magazines", KSTAT_DATA_UINT64 }, 902 { "magazine_size", KSTAT_DATA_UINT64 }, 903 { "reap", KSTAT_DATA_UINT64 }, 904 { "defrag", KSTAT_DATA_UINT64 }, 905 { "scan", KSTAT_DATA_UINT64 }, 906 { "move_callbacks", KSTAT_DATA_UINT64 }, 907 { "move_yes", KSTAT_DATA_UINT64 }, 908 { "move_no", KSTAT_DATA_UINT64 }, 909 { "move_later", KSTAT_DATA_UINT64 }, 910 { "move_dont_need", KSTAT_DATA_UINT64 }, 911 { "move_dont_know", KSTAT_DATA_UINT64 }, 912 { "move_hunt_found", KSTAT_DATA_UINT64 }, 913 { "move_slabs_freed", KSTAT_DATA_UINT64 }, 914 { "move_reclaimable", KSTAT_DATA_UINT64 }, 915 }; 916 917 static kmutex_t kmem_cache_kstat_lock; 918 919 /* 920 * The default set of caches to back kmem_alloc(). 921 * These sizes should be reevaluated periodically. 922 * 923 * We want allocations that are multiples of the coherency granularity 924 * (64 bytes) to be satisfied from a cache which is a multiple of 64 925 * bytes, so that it will be 64-byte aligned. For all multiples of 64, 926 * the next kmem_cache_size greater than or equal to it must be a 927 * multiple of 64. 928 * 929 * We split the table into two sections: size <= 4k and size > 4k. This 930 * saves a lot of space and cache footprint in our cache tables. 931 */ 932 static const int kmem_alloc_sizes[] = { 933 1 * 8, 934 2 * 8, 935 3 * 8, 936 4 * 8, 5 * 8, 6 * 8, 7 * 8, 937 4 * 16, 5 * 16, 6 * 16, 7 * 16, 938 4 * 32, 5 * 32, 6 * 32, 7 * 32, 939 4 * 64, 5 * 64, 6 * 64, 7 * 64, 940 4 * 128, 5 * 128, 6 * 128, 7 * 128, 941 P2ALIGN(8192 / 7, 64), 942 P2ALIGN(8192 / 6, 64), 943 P2ALIGN(8192 / 5, 64), 944 P2ALIGN(8192 / 4, 64), 945 P2ALIGN(8192 / 3, 64), 946 P2ALIGN(8192 / 2, 64), 947 }; 948 949 static const int kmem_big_alloc_sizes[] = { 950 2 * 4096, 3 * 4096, 951 2 * 8192, 3 * 8192, 952 4 * 8192, 5 * 8192, 6 * 8192, 7 * 8192, 953 8 * 8192, 9 * 8192, 10 * 8192, 11 * 8192, 954 12 * 8192, 13 * 8192, 14 * 8192, 15 * 8192, 955 16 * 8192 956 }; 957 958 #define KMEM_MAXBUF 4096 959 #define KMEM_BIG_MAXBUF_32BIT 32768 960 #define KMEM_BIG_MAXBUF 131072 961 962 #define KMEM_BIG_MULTIPLE 4096 /* big_alloc_sizes must be a multiple */ 963 #define KMEM_BIG_SHIFT 12 /* lg(KMEM_BIG_MULTIPLE) */ 964 965 static kmem_cache_t *kmem_alloc_table[KMEM_MAXBUF >> KMEM_ALIGN_SHIFT]; 966 static kmem_cache_t *kmem_big_alloc_table[KMEM_BIG_MAXBUF >> KMEM_BIG_SHIFT]; 967 968 #define KMEM_ALLOC_TABLE_MAX (KMEM_MAXBUF >> KMEM_ALIGN_SHIFT) 969 static size_t kmem_big_alloc_table_max = 0; /* # of filled elements */ 970 971 static kmem_magtype_t kmem_magtype[] = { 972 { 1, 8, 3200, 65536 }, 973 { 3, 16, 256, 32768 }, 974 { 7, 32, 64, 16384 }, 975 { 15, 64, 0, 8192 }, 976 { 31, 64, 0, 4096 }, 977 { 47, 64, 0, 2048 }, 978 { 63, 64, 0, 1024 }, 979 { 95, 64, 0, 512 }, 980 { 143, 64, 0, 0 }, 981 }; 982 983 static uint32_t kmem_reaping; 984 static uint32_t kmem_reaping_idspace; 985 986 /* 987 * kmem tunables 988 */ 989 clock_t kmem_reap_interval; /* cache reaping rate [15 * HZ ticks] */ 990 int kmem_depot_contention = 3; /* max failed tryenters per real interval */ 991 pgcnt_t kmem_reapahead = 0; /* start reaping N pages before pageout */ 992 int kmem_panic = 1; /* whether to panic on error */ 993 int kmem_logging = 1; /* kmem_log_enter() override */ 994 uint32_t kmem_mtbf = 0; /* mean time between failures [default: off] */ 995 size_t kmem_transaction_log_size; /* transaction log size [2% of memory] */ 996 size_t kmem_content_log_size; /* content log size [2% of memory] */ 997 size_t kmem_failure_log_size; /* failure log [4 pages per CPU] */ 998 size_t kmem_slab_log_size; /* slab create log [4 pages per CPU] */ 999 size_t kmem_content_maxsave = 256; /* KMF_CONTENTS max bytes to log */ 1000 size_t kmem_lite_minsize = 0; /* minimum buffer size for KMF_LITE */ 1001 size_t kmem_lite_maxalign = 1024; /* maximum buffer alignment for KMF_LITE */ 1002 int kmem_lite_pcs = 4; /* number of PCs to store in KMF_LITE mode */ 1003 size_t kmem_maxverify; /* maximum bytes to inspect in debug routines */ 1004 size_t kmem_minfirewall; /* hardware-enforced redzone threshold */ 1005 1006 #ifdef _LP64 1007 size_t kmem_max_cached = KMEM_BIG_MAXBUF; /* maximum kmem_alloc cache */ 1008 #else 1009 size_t kmem_max_cached = KMEM_BIG_MAXBUF_32BIT; /* maximum kmem_alloc cache */ 1010 #endif 1011 1012 #ifdef DEBUG 1013 int kmem_flags = KMF_AUDIT | KMF_DEADBEEF | KMF_REDZONE | KMF_CONTENTS; 1014 #else 1015 int kmem_flags = 0; 1016 #endif 1017 int kmem_ready; 1018 1019 static kmem_cache_t *kmem_slab_cache; 1020 static kmem_cache_t *kmem_bufctl_cache; 1021 static kmem_cache_t *kmem_bufctl_audit_cache; 1022 1023 static kmutex_t kmem_cache_lock; /* inter-cache linkage only */ 1024 static list_t kmem_caches; 1025 1026 static taskq_t *kmem_taskq; 1027 static kmutex_t kmem_flags_lock; 1028 static vmem_t *kmem_metadata_arena; 1029 static vmem_t *kmem_msb_arena; /* arena for metadata caches */ 1030 static vmem_t *kmem_cache_arena; 1031 static vmem_t *kmem_hash_arena; 1032 static vmem_t *kmem_log_arena; 1033 static vmem_t *kmem_oversize_arena; 1034 static vmem_t *kmem_va_arena; 1035 static vmem_t *kmem_default_arena; 1036 static vmem_t *kmem_firewall_va_arena; 1037 static vmem_t *kmem_firewall_arena; 1038 1039 /* 1040 * Define KMEM_STATS to turn on statistic gathering. By default, it is only 1041 * turned on when DEBUG is also defined. 1042 */ 1043 #ifdef DEBUG 1044 #define KMEM_STATS 1045 #endif /* DEBUG */ 1046 1047 #ifdef KMEM_STATS 1048 #define KMEM_STAT_ADD(stat) ((stat)++) 1049 #define KMEM_STAT_COND_ADD(cond, stat) ((void) (!(cond) || (stat)++)) 1050 #else 1051 #define KMEM_STAT_ADD(stat) /* nothing */ 1052 #define KMEM_STAT_COND_ADD(cond, stat) /* nothing */ 1053 #endif /* KMEM_STATS */ 1054 1055 /* 1056 * kmem slab consolidator thresholds (tunables) 1057 */ 1058 size_t kmem_frag_minslabs = 101; /* minimum total slabs */ 1059 size_t kmem_frag_numer = 1; /* free buffers (numerator) */ 1060 size_t kmem_frag_denom = KMEM_VOID_FRACTION; /* buffers (denominator) */ 1061 /* 1062 * Maximum number of slabs from which to move buffers during a single 1063 * maintenance interval while the system is not low on memory. 1064 */ 1065 size_t kmem_reclaim_max_slabs = 1; 1066 /* 1067 * Number of slabs to scan backwards from the end of the partial slab list 1068 * when searching for buffers to relocate. 1069 */ 1070 size_t kmem_reclaim_scan_range = 12; 1071 1072 #ifdef KMEM_STATS 1073 static struct { 1074 uint64_t kms_callbacks; 1075 uint64_t kms_yes; 1076 uint64_t kms_no; 1077 uint64_t kms_later; 1078 uint64_t kms_dont_need; 1079 uint64_t kms_dont_know; 1080 uint64_t kms_hunt_found_mag; 1081 uint64_t kms_hunt_found_slab; 1082 uint64_t kms_hunt_alloc_fail; 1083 uint64_t kms_hunt_lucky; 1084 uint64_t kms_notify; 1085 uint64_t kms_notify_callbacks; 1086 uint64_t kms_disbelief; 1087 uint64_t kms_already_pending; 1088 uint64_t kms_callback_alloc_fail; 1089 uint64_t kms_callback_taskq_fail; 1090 uint64_t kms_endscan_slab_dead; 1091 uint64_t kms_endscan_slab_destroyed; 1092 uint64_t kms_endscan_nomem; 1093 uint64_t kms_endscan_refcnt_changed; 1094 uint64_t kms_endscan_nomove_changed; 1095 uint64_t kms_endscan_freelist; 1096 uint64_t kms_avl_update; 1097 uint64_t kms_avl_noupdate; 1098 uint64_t kms_no_longer_reclaimable; 1099 uint64_t kms_notify_no_longer_reclaimable; 1100 uint64_t kms_notify_slab_dead; 1101 uint64_t kms_notify_slab_destroyed; 1102 uint64_t kms_alloc_fail; 1103 uint64_t kms_constructor_fail; 1104 uint64_t kms_dead_slabs_freed; 1105 uint64_t kms_defrags; 1106 uint64_t kms_scans; 1107 uint64_t kms_scan_depot_ws_reaps; 1108 uint64_t kms_debug_reaps; 1109 uint64_t kms_debug_scans; 1110 } kmem_move_stats; 1111 #endif /* KMEM_STATS */ 1112 1113 /* consolidator knobs */ 1114 static boolean_t kmem_move_noreap; 1115 static boolean_t kmem_move_blocked; 1116 static boolean_t kmem_move_fulltilt; 1117 static boolean_t kmem_move_any_partial; 1118 1119 #ifdef DEBUG 1120 /* 1121 * kmem consolidator debug tunables: 1122 * Ensure code coverage by occasionally running the consolidator even when the 1123 * caches are not fragmented (they may never be). These intervals are mean time 1124 * in cache maintenance intervals (kmem_cache_update). 1125 */ 1126 uint32_t kmem_mtb_move = 60; /* defrag 1 slab (~15min) */ 1127 uint32_t kmem_mtb_reap = 1800; /* defrag all slabs (~7.5hrs) */ 1128 #endif /* DEBUG */ 1129 1130 static kmem_cache_t *kmem_defrag_cache; 1131 static kmem_cache_t *kmem_move_cache; 1132 static taskq_t *kmem_move_taskq; 1133 1134 static void kmem_cache_scan(kmem_cache_t *); 1135 static void kmem_cache_defrag(kmem_cache_t *); 1136 static void kmem_slab_prefill(kmem_cache_t *, kmem_slab_t *); 1137 1138 1139 kmem_log_header_t *kmem_transaction_log; 1140 kmem_log_header_t *kmem_content_log; 1141 kmem_log_header_t *kmem_failure_log; 1142 kmem_log_header_t *kmem_slab_log; 1143 1144 static int kmem_lite_count; /* # of PCs in kmem_buftag_lite_t */ 1145 1146 #define KMEM_BUFTAG_LITE_ENTER(bt, count, caller) \ 1147 if ((count) > 0) { \ 1148 pc_t *_s = ((kmem_buftag_lite_t *)(bt))->bt_history; \ 1149 pc_t *_e; \ 1150 /* memmove() the old entries down one notch */ \ 1151 for (_e = &_s[(count) - 1]; _e > _s; _e--) \ 1152 *_e = *(_e - 1); \ 1153 *_s = (uintptr_t)(caller); \ 1154 } 1155 1156 #define KMERR_MODIFIED 0 /* buffer modified while on freelist */ 1157 #define KMERR_REDZONE 1 /* redzone violation (write past end of buf) */ 1158 #define KMERR_DUPFREE 2 /* freed a buffer twice */ 1159 #define KMERR_BADADDR 3 /* freed a bad (unallocated) address */ 1160 #define KMERR_BADBUFTAG 4 /* buftag corrupted */ 1161 #define KMERR_BADBUFCTL 5 /* bufctl corrupted */ 1162 #define KMERR_BADCACHE 6 /* freed a buffer to the wrong cache */ 1163 #define KMERR_BADSIZE 7 /* alloc size != free size */ 1164 #define KMERR_BADBASE 8 /* buffer base address wrong */ 1165 1166 struct { 1167 hrtime_t kmp_timestamp; /* timestamp of panic */ 1168 int kmp_error; /* type of kmem error */ 1169 void *kmp_buffer; /* buffer that induced panic */ 1170 void *kmp_realbuf; /* real start address for buffer */ 1171 kmem_cache_t *kmp_cache; /* buffer's cache according to client */ 1172 kmem_cache_t *kmp_realcache; /* actual cache containing buffer */ 1173 kmem_slab_t *kmp_slab; /* slab accoring to kmem_findslab() */ 1174 kmem_bufctl_t *kmp_bufctl; /* bufctl */ 1175 } kmem_panic_info; 1176 1177 1178 static void 1179 copy_pattern(uint64_t pattern, void *buf_arg, size_t size) 1180 { 1181 uint64_t *bufend = (uint64_t *)((char *)buf_arg + size); 1182 uint64_t *buf = buf_arg; 1183 1184 while (buf < bufend) 1185 *buf++ = pattern; 1186 } 1187 1188 static void * 1189 verify_pattern(uint64_t pattern, void *buf_arg, size_t size) 1190 { 1191 uint64_t *bufend = (uint64_t *)((char *)buf_arg + size); 1192 uint64_t *buf; 1193 1194 for (buf = buf_arg; buf < bufend; buf++) 1195 if (*buf != pattern) 1196 return (buf); 1197 return (NULL); 1198 } 1199 1200 static void * 1201 verify_and_copy_pattern(uint64_t old, uint64_t new, void *buf_arg, size_t size) 1202 { 1203 uint64_t *bufend = (uint64_t *)((char *)buf_arg + size); 1204 uint64_t *buf; 1205 1206 for (buf = buf_arg; buf < bufend; buf++) { 1207 if (*buf != old) { 1208 copy_pattern(old, buf_arg, 1209 (char *)buf - (char *)buf_arg); 1210 return (buf); 1211 } 1212 *buf = new; 1213 } 1214 1215 return (NULL); 1216 } 1217 1218 static void 1219 kmem_cache_applyall(void (*func)(kmem_cache_t *), taskq_t *tq, int tqflag) 1220 { 1221 kmem_cache_t *cp; 1222 1223 mutex_enter(&kmem_cache_lock); 1224 for (cp = list_head(&kmem_caches); cp != NULL; 1225 cp = list_next(&kmem_caches, cp)) 1226 if (tq != NULL) 1227 (void) taskq_dispatch(tq, (task_func_t *)func, cp, 1228 tqflag); 1229 else 1230 func(cp); 1231 mutex_exit(&kmem_cache_lock); 1232 } 1233 1234 static void 1235 kmem_cache_applyall_id(void (*func)(kmem_cache_t *), taskq_t *tq, int tqflag) 1236 { 1237 kmem_cache_t *cp; 1238 1239 mutex_enter(&kmem_cache_lock); 1240 for (cp = list_head(&kmem_caches); cp != NULL; 1241 cp = list_next(&kmem_caches, cp)) { 1242 if (!(cp->cache_cflags & KMC_IDENTIFIER)) 1243 continue; 1244 if (tq != NULL) 1245 (void) taskq_dispatch(tq, (task_func_t *)func, cp, 1246 tqflag); 1247 else 1248 func(cp); 1249 } 1250 mutex_exit(&kmem_cache_lock); 1251 } 1252 1253 /* 1254 * Debugging support. Given a buffer address, find its slab. 1255 */ 1256 static kmem_slab_t * 1257 kmem_findslab(kmem_cache_t *cp, void *buf) 1258 { 1259 kmem_slab_t *sp; 1260 1261 mutex_enter(&cp->cache_lock); 1262 for (sp = list_head(&cp->cache_complete_slabs); sp != NULL; 1263 sp = list_next(&cp->cache_complete_slabs, sp)) { 1264 if (KMEM_SLAB_MEMBER(sp, buf)) { 1265 mutex_exit(&cp->cache_lock); 1266 return (sp); 1267 } 1268 } 1269 for (sp = avl_first(&cp->cache_partial_slabs); sp != NULL; 1270 sp = AVL_NEXT(&cp->cache_partial_slabs, sp)) { 1271 if (KMEM_SLAB_MEMBER(sp, buf)) { 1272 mutex_exit(&cp->cache_lock); 1273 return (sp); 1274 } 1275 } 1276 mutex_exit(&cp->cache_lock); 1277 1278 return (NULL); 1279 } 1280 1281 static void 1282 kmem_error(int error, kmem_cache_t *cparg, void *bufarg) 1283 { 1284 kmem_buftag_t *btp = NULL; 1285 kmem_bufctl_t *bcp = NULL; 1286 kmem_cache_t *cp = cparg; 1287 kmem_slab_t *sp; 1288 uint64_t *off; 1289 void *buf = bufarg; 1290 1291 kmem_logging = 0; /* stop logging when a bad thing happens */ 1292 1293 kmem_panic_info.kmp_timestamp = gethrtime(); 1294 1295 sp = kmem_findslab(cp, buf); 1296 if (sp == NULL) { 1297 for (cp = list_tail(&kmem_caches); cp != NULL; 1298 cp = list_prev(&kmem_caches, cp)) { 1299 if ((sp = kmem_findslab(cp, buf)) != NULL) 1300 break; 1301 } 1302 } 1303 1304 if (sp == NULL) { 1305 cp = NULL; 1306 error = KMERR_BADADDR; 1307 } else { 1308 if (cp != cparg) 1309 error = KMERR_BADCACHE; 1310 else 1311 buf = (char *)bufarg - ((uintptr_t)bufarg - 1312 (uintptr_t)sp->slab_base) % cp->cache_chunksize; 1313 if (buf != bufarg) 1314 error = KMERR_BADBASE; 1315 if (cp->cache_flags & KMF_BUFTAG) 1316 btp = KMEM_BUFTAG(cp, buf); 1317 if (cp->cache_flags & KMF_HASH) { 1318 mutex_enter(&cp->cache_lock); 1319 for (bcp = *KMEM_HASH(cp, buf); bcp; bcp = bcp->bc_next) 1320 if (bcp->bc_addr == buf) 1321 break; 1322 mutex_exit(&cp->cache_lock); 1323 if (bcp == NULL && btp != NULL) 1324 bcp = btp->bt_bufctl; 1325 if (kmem_findslab(cp->cache_bufctl_cache, bcp) == 1326 NULL || P2PHASE((uintptr_t)bcp, KMEM_ALIGN) || 1327 bcp->bc_addr != buf) { 1328 error = KMERR_BADBUFCTL; 1329 bcp = NULL; 1330 } 1331 } 1332 } 1333 1334 kmem_panic_info.kmp_error = error; 1335 kmem_panic_info.kmp_buffer = bufarg; 1336 kmem_panic_info.kmp_realbuf = buf; 1337 kmem_panic_info.kmp_cache = cparg; 1338 kmem_panic_info.kmp_realcache = cp; 1339 kmem_panic_info.kmp_slab = sp; 1340 kmem_panic_info.kmp_bufctl = bcp; 1341 1342 printf("kernel memory allocator: "); 1343 1344 switch (error) { 1345 1346 case KMERR_MODIFIED: 1347 printf("buffer modified after being freed\n"); 1348 off = verify_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify); 1349 if (off == NULL) /* shouldn't happen */ 1350 off = buf; 1351 printf("modification occurred at offset 0x%lx " 1352 "(0x%llx replaced by 0x%llx)\n", 1353 (uintptr_t)off - (uintptr_t)buf, 1354 (longlong_t)KMEM_FREE_PATTERN, (longlong_t)*off); 1355 break; 1356 1357 case KMERR_REDZONE: 1358 printf("redzone violation: write past end of buffer\n"); 1359 break; 1360 1361 case KMERR_BADADDR: 1362 printf("invalid free: buffer not in cache\n"); 1363 break; 1364 1365 case KMERR_DUPFREE: 1366 printf("duplicate free: buffer freed twice\n"); 1367 break; 1368 1369 case KMERR_BADBUFTAG: 1370 printf("boundary tag corrupted\n"); 1371 printf("bcp ^ bxstat = %lx, should be %lx\n", 1372 (intptr_t)btp->bt_bufctl ^ btp->bt_bxstat, 1373 KMEM_BUFTAG_FREE); 1374 break; 1375 1376 case KMERR_BADBUFCTL: 1377 printf("bufctl corrupted\n"); 1378 break; 1379 1380 case KMERR_BADCACHE: 1381 printf("buffer freed to wrong cache\n"); 1382 printf("buffer was allocated from %s,\n", cp->cache_name); 1383 printf("caller attempting free to %s.\n", cparg->cache_name); 1384 break; 1385 1386 case KMERR_BADSIZE: 1387 printf("bad free: free size (%u) != alloc size (%u)\n", 1388 KMEM_SIZE_DECODE(((uint32_t *)btp)[0]), 1389 KMEM_SIZE_DECODE(((uint32_t *)btp)[1])); 1390 break; 1391 1392 case KMERR_BADBASE: 1393 printf("bad free: free address (%p) != alloc address (%p)\n", 1394 bufarg, buf); 1395 break; 1396 } 1397 1398 printf("buffer=%p bufctl=%p cache: %s\n", 1399 bufarg, (void *)bcp, cparg->cache_name); 1400 1401 if (bcp != NULL && (cp->cache_flags & KMF_AUDIT) && 1402 error != KMERR_BADBUFCTL) { 1403 int d; 1404 timestruc_t ts; 1405 kmem_bufctl_audit_t *bcap = (kmem_bufctl_audit_t *)bcp; 1406 1407 hrt2ts(kmem_panic_info.kmp_timestamp - bcap->bc_timestamp, &ts); 1408 printf("previous transaction on buffer %p:\n", buf); 1409 printf("thread=%p time=T-%ld.%09ld slab=%p cache: %s\n", 1410 (void *)bcap->bc_thread, ts.tv_sec, ts.tv_nsec, 1411 (void *)sp, cp->cache_name); 1412 for (d = 0; d < MIN(bcap->bc_depth, KMEM_STACK_DEPTH); d++) { 1413 ulong_t off; 1414 char *sym = kobj_getsymname(bcap->bc_stack[d], &off); 1415 printf("%s+%lx\n", sym ? sym : "?", off); 1416 } 1417 } 1418 if (kmem_panic > 0) 1419 panic("kernel heap corruption detected"); 1420 if (kmem_panic == 0) 1421 debug_enter(NULL); 1422 kmem_logging = 1; /* resume logging */ 1423 } 1424 1425 static kmem_log_header_t * 1426 kmem_log_init(size_t logsize) 1427 { 1428 kmem_log_header_t *lhp; 1429 int nchunks = 4 * max_ncpus; 1430 size_t lhsize = (size_t)&((kmem_log_header_t *)0)->lh_cpu[max_ncpus]; 1431 int i; 1432 1433 /* 1434 * Make sure that lhp->lh_cpu[] is nicely aligned 1435 * to prevent false sharing of cache lines. 1436 */ 1437 lhsize = P2ROUNDUP(lhsize, KMEM_ALIGN); 1438 lhp = vmem_xalloc(kmem_log_arena, lhsize, 64, P2NPHASE(lhsize, 64), 0, 1439 NULL, NULL, VM_SLEEP); 1440 bzero(lhp, lhsize); 1441 1442 mutex_init(&lhp->lh_lock, NULL, MUTEX_DEFAULT, NULL); 1443 lhp->lh_nchunks = nchunks; 1444 lhp->lh_chunksize = P2ROUNDUP(logsize / nchunks + 1, PAGESIZE); 1445 lhp->lh_base = vmem_alloc(kmem_log_arena, 1446 lhp->lh_chunksize * nchunks, VM_SLEEP); 1447 lhp->lh_free = vmem_alloc(kmem_log_arena, 1448 nchunks * sizeof (int), VM_SLEEP); 1449 bzero(lhp->lh_base, lhp->lh_chunksize * nchunks); 1450 1451 for (i = 0; i < max_ncpus; i++) { 1452 kmem_cpu_log_header_t *clhp = &lhp->lh_cpu[i]; 1453 mutex_init(&clhp->clh_lock, NULL, MUTEX_DEFAULT, NULL); 1454 clhp->clh_chunk = i; 1455 } 1456 1457 for (i = max_ncpus; i < nchunks; i++) 1458 lhp->lh_free[i] = i; 1459 1460 lhp->lh_head = max_ncpus; 1461 lhp->lh_tail = 0; 1462 1463 return (lhp); 1464 } 1465 1466 static void * 1467 kmem_log_enter(kmem_log_header_t *lhp, void *data, size_t size) 1468 { 1469 void *logspace; 1470 kmem_cpu_log_header_t *clhp = &lhp->lh_cpu[CPU->cpu_seqid]; 1471 1472 if (lhp == NULL || kmem_logging == 0 || panicstr) 1473 return (NULL); 1474 1475 mutex_enter(&clhp->clh_lock); 1476 clhp->clh_hits++; 1477 if (size > clhp->clh_avail) { 1478 mutex_enter(&lhp->lh_lock); 1479 lhp->lh_hits++; 1480 lhp->lh_free[lhp->lh_tail] = clhp->clh_chunk; 1481 lhp->lh_tail = (lhp->lh_tail + 1) % lhp->lh_nchunks; 1482 clhp->clh_chunk = lhp->lh_free[lhp->lh_head]; 1483 lhp->lh_head = (lhp->lh_head + 1) % lhp->lh_nchunks; 1484 clhp->clh_current = lhp->lh_base + 1485 clhp->clh_chunk * lhp->lh_chunksize; 1486 clhp->clh_avail = lhp->lh_chunksize; 1487 if (size > lhp->lh_chunksize) 1488 size = lhp->lh_chunksize; 1489 mutex_exit(&lhp->lh_lock); 1490 } 1491 logspace = clhp->clh_current; 1492 clhp->clh_current += size; 1493 clhp->clh_avail -= size; 1494 bcopy(data, logspace, size); 1495 mutex_exit(&clhp->clh_lock); 1496 return (logspace); 1497 } 1498 1499 #define KMEM_AUDIT(lp, cp, bcp) \ 1500 { \ 1501 kmem_bufctl_audit_t *_bcp = (kmem_bufctl_audit_t *)(bcp); \ 1502 _bcp->bc_timestamp = gethrtime(); \ 1503 _bcp->bc_thread = curthread; \ 1504 _bcp->bc_depth = getpcstack(_bcp->bc_stack, KMEM_STACK_DEPTH); \ 1505 _bcp->bc_lastlog = kmem_log_enter((lp), _bcp, sizeof (*_bcp)); \ 1506 } 1507 1508 static void 1509 kmem_log_event(kmem_log_header_t *lp, kmem_cache_t *cp, 1510 kmem_slab_t *sp, void *addr) 1511 { 1512 kmem_bufctl_audit_t bca; 1513 1514 bzero(&bca, sizeof (kmem_bufctl_audit_t)); 1515 bca.bc_addr = addr; 1516 bca.bc_slab = sp; 1517 bca.bc_cache = cp; 1518 KMEM_AUDIT(lp, cp, &bca); 1519 } 1520 1521 /* 1522 * Create a new slab for cache cp. 1523 */ 1524 static kmem_slab_t * 1525 kmem_slab_create(kmem_cache_t *cp, int kmflag) 1526 { 1527 size_t slabsize = cp->cache_slabsize; 1528 size_t chunksize = cp->cache_chunksize; 1529 int cache_flags = cp->cache_flags; 1530 size_t color, chunks; 1531 char *buf, *slab; 1532 kmem_slab_t *sp; 1533 kmem_bufctl_t *bcp; 1534 vmem_t *vmp = cp->cache_arena; 1535 1536 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 1537 1538 color = cp->cache_color + cp->cache_align; 1539 if (color > cp->cache_maxcolor) 1540 color = cp->cache_mincolor; 1541 cp->cache_color = color; 1542 1543 slab = vmem_alloc(vmp, slabsize, kmflag & KM_VMFLAGS); 1544 1545 if (slab == NULL) 1546 goto vmem_alloc_failure; 1547 1548 ASSERT(P2PHASE((uintptr_t)slab, vmp->vm_quantum) == 0); 1549 1550 /* 1551 * Reverify what was already checked in kmem_cache_set_move(), since the 1552 * consolidator depends (for correctness) on slabs being initialized 1553 * with the 0xbaddcafe memory pattern (setting a low order bit usable by 1554 * clients to distinguish uninitialized memory from known objects). 1555 */ 1556 ASSERT((cp->cache_move == NULL) || !(cp->cache_cflags & KMC_NOTOUCH)); 1557 if (!(cp->cache_cflags & KMC_NOTOUCH)) 1558 copy_pattern(KMEM_UNINITIALIZED_PATTERN, slab, slabsize); 1559 1560 if (cache_flags & KMF_HASH) { 1561 if ((sp = kmem_cache_alloc(kmem_slab_cache, kmflag)) == NULL) 1562 goto slab_alloc_failure; 1563 chunks = (slabsize - color) / chunksize; 1564 } else { 1565 sp = KMEM_SLAB(cp, slab); 1566 chunks = (slabsize - sizeof (kmem_slab_t) - color) / chunksize; 1567 } 1568 1569 sp->slab_cache = cp; 1570 sp->slab_head = NULL; 1571 sp->slab_refcnt = 0; 1572 sp->slab_base = buf = slab + color; 1573 sp->slab_chunks = chunks; 1574 sp->slab_stuck_offset = (uint32_t)-1; 1575 sp->slab_later_count = 0; 1576 sp->slab_flags = 0; 1577 1578 ASSERT(chunks > 0); 1579 while (chunks-- != 0) { 1580 if (cache_flags & KMF_HASH) { 1581 bcp = kmem_cache_alloc(cp->cache_bufctl_cache, kmflag); 1582 if (bcp == NULL) 1583 goto bufctl_alloc_failure; 1584 if (cache_flags & KMF_AUDIT) { 1585 kmem_bufctl_audit_t *bcap = 1586 (kmem_bufctl_audit_t *)bcp; 1587 bzero(bcap, sizeof (kmem_bufctl_audit_t)); 1588 bcap->bc_cache = cp; 1589 } 1590 bcp->bc_addr = buf; 1591 bcp->bc_slab = sp; 1592 } else { 1593 bcp = KMEM_BUFCTL(cp, buf); 1594 } 1595 if (cache_flags & KMF_BUFTAG) { 1596 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 1597 btp->bt_redzone = KMEM_REDZONE_PATTERN; 1598 btp->bt_bufctl = bcp; 1599 btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE; 1600 if (cache_flags & KMF_DEADBEEF) { 1601 copy_pattern(KMEM_FREE_PATTERN, buf, 1602 cp->cache_verify); 1603 } 1604 } 1605 bcp->bc_next = sp->slab_head; 1606 sp->slab_head = bcp; 1607 buf += chunksize; 1608 } 1609 1610 kmem_log_event(kmem_slab_log, cp, sp, slab); 1611 1612 return (sp); 1613 1614 bufctl_alloc_failure: 1615 1616 while ((bcp = sp->slab_head) != NULL) { 1617 sp->slab_head = bcp->bc_next; 1618 kmem_cache_free(cp->cache_bufctl_cache, bcp); 1619 } 1620 kmem_cache_free(kmem_slab_cache, sp); 1621 1622 slab_alloc_failure: 1623 1624 vmem_free(vmp, slab, slabsize); 1625 1626 vmem_alloc_failure: 1627 1628 kmem_log_event(kmem_failure_log, cp, NULL, NULL); 1629 atomic_inc_64(&cp->cache_alloc_fail); 1630 1631 return (NULL); 1632 } 1633 1634 /* 1635 * Destroy a slab. 1636 */ 1637 static void 1638 kmem_slab_destroy(kmem_cache_t *cp, kmem_slab_t *sp) 1639 { 1640 vmem_t *vmp = cp->cache_arena; 1641 void *slab = (void *)P2ALIGN((uintptr_t)sp->slab_base, vmp->vm_quantum); 1642 1643 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 1644 ASSERT(sp->slab_refcnt == 0); 1645 1646 if (cp->cache_flags & KMF_HASH) { 1647 kmem_bufctl_t *bcp; 1648 while ((bcp = sp->slab_head) != NULL) { 1649 sp->slab_head = bcp->bc_next; 1650 kmem_cache_free(cp->cache_bufctl_cache, bcp); 1651 } 1652 kmem_cache_free(kmem_slab_cache, sp); 1653 } 1654 vmem_free(vmp, slab, cp->cache_slabsize); 1655 } 1656 1657 static void * 1658 kmem_slab_alloc_impl(kmem_cache_t *cp, kmem_slab_t *sp, boolean_t prefill) 1659 { 1660 kmem_bufctl_t *bcp, **hash_bucket; 1661 void *buf; 1662 boolean_t new_slab = (sp->slab_refcnt == 0); 1663 1664 ASSERT(MUTEX_HELD(&cp->cache_lock)); 1665 /* 1666 * kmem_slab_alloc() drops cache_lock when it creates a new slab, so we 1667 * can't ASSERT(avl_is_empty(&cp->cache_partial_slabs)) here when the 1668 * slab is newly created. 1669 */ 1670 ASSERT(new_slab || (KMEM_SLAB_IS_PARTIAL(sp) && 1671 (sp == avl_first(&cp->cache_partial_slabs)))); 1672 ASSERT(sp->slab_cache == cp); 1673 1674 cp->cache_slab_alloc++; 1675 cp->cache_bufslab--; 1676 sp->slab_refcnt++; 1677 1678 bcp = sp->slab_head; 1679 sp->slab_head = bcp->bc_next; 1680 1681 if (cp->cache_flags & KMF_HASH) { 1682 /* 1683 * Add buffer to allocated-address hash table. 1684 */ 1685 buf = bcp->bc_addr; 1686 hash_bucket = KMEM_HASH(cp, buf); 1687 bcp->bc_next = *hash_bucket; 1688 *hash_bucket = bcp; 1689 if ((cp->cache_flags & (KMF_AUDIT | KMF_BUFTAG)) == KMF_AUDIT) { 1690 KMEM_AUDIT(kmem_transaction_log, cp, bcp); 1691 } 1692 } else { 1693 buf = KMEM_BUF(cp, bcp); 1694 } 1695 1696 ASSERT(KMEM_SLAB_MEMBER(sp, buf)); 1697 1698 if (sp->slab_head == NULL) { 1699 ASSERT(KMEM_SLAB_IS_ALL_USED(sp)); 1700 if (new_slab) { 1701 ASSERT(sp->slab_chunks == 1); 1702 } else { 1703 ASSERT(sp->slab_chunks > 1); /* the slab was partial */ 1704 avl_remove(&cp->cache_partial_slabs, sp); 1705 sp->slab_later_count = 0; /* clear history */ 1706 sp->slab_flags &= ~KMEM_SLAB_NOMOVE; 1707 sp->slab_stuck_offset = (uint32_t)-1; 1708 } 1709 list_insert_head(&cp->cache_complete_slabs, sp); 1710 cp->cache_complete_slab_count++; 1711 return (buf); 1712 } 1713 1714 ASSERT(KMEM_SLAB_IS_PARTIAL(sp)); 1715 /* 1716 * Peek to see if the magazine layer is enabled before 1717 * we prefill. We're not holding the cpu cache lock, 1718 * so the peek could be wrong, but there's no harm in it. 1719 */ 1720 if (new_slab && prefill && (cp->cache_flags & KMF_PREFILL) && 1721 (KMEM_CPU_CACHE(cp)->cc_magsize != 0)) { 1722 kmem_slab_prefill(cp, sp); 1723 return (buf); 1724 } 1725 1726 if (new_slab) { 1727 avl_add(&cp->cache_partial_slabs, sp); 1728 return (buf); 1729 } 1730 1731 /* 1732 * The slab is now more allocated than it was, so the 1733 * order remains unchanged. 1734 */ 1735 ASSERT(!avl_update(&cp->cache_partial_slabs, sp)); 1736 return (buf); 1737 } 1738 1739 /* 1740 * Allocate a raw (unconstructed) buffer from cp's slab layer. 1741 */ 1742 static void * 1743 kmem_slab_alloc(kmem_cache_t *cp, int kmflag) 1744 { 1745 kmem_slab_t *sp; 1746 void *buf; 1747 boolean_t test_destructor; 1748 1749 mutex_enter(&cp->cache_lock); 1750 test_destructor = (cp->cache_slab_alloc == 0); 1751 sp = avl_first(&cp->cache_partial_slabs); 1752 if (sp == NULL) { 1753 ASSERT(cp->cache_bufslab == 0); 1754 1755 /* 1756 * The freelist is empty. Create a new slab. 1757 */ 1758 mutex_exit(&cp->cache_lock); 1759 if ((sp = kmem_slab_create(cp, kmflag)) == NULL) { 1760 return (NULL); 1761 } 1762 mutex_enter(&cp->cache_lock); 1763 cp->cache_slab_create++; 1764 if ((cp->cache_buftotal += sp->slab_chunks) > cp->cache_bufmax) 1765 cp->cache_bufmax = cp->cache_buftotal; 1766 cp->cache_bufslab += sp->slab_chunks; 1767 } 1768 1769 buf = kmem_slab_alloc_impl(cp, sp, B_TRUE); 1770 ASSERT((cp->cache_slab_create - cp->cache_slab_destroy) == 1771 (cp->cache_complete_slab_count + 1772 avl_numnodes(&cp->cache_partial_slabs) + 1773 (cp->cache_defrag == NULL ? 0 : cp->cache_defrag->kmd_deadcount))); 1774 mutex_exit(&cp->cache_lock); 1775 1776 if (test_destructor && cp->cache_destructor != NULL) { 1777 /* 1778 * On the first kmem_slab_alloc(), assert that it is valid to 1779 * call the destructor on a newly constructed object without any 1780 * client involvement. 1781 */ 1782 if ((cp->cache_constructor == NULL) || 1783 cp->cache_constructor(buf, cp->cache_private, 1784 kmflag) == 0) { 1785 cp->cache_destructor(buf, cp->cache_private); 1786 } 1787 copy_pattern(KMEM_UNINITIALIZED_PATTERN, buf, 1788 cp->cache_bufsize); 1789 if (cp->cache_flags & KMF_DEADBEEF) { 1790 copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify); 1791 } 1792 } 1793 1794 return (buf); 1795 } 1796 1797 static void kmem_slab_move_yes(kmem_cache_t *, kmem_slab_t *, void *); 1798 1799 /* 1800 * Free a raw (unconstructed) buffer to cp's slab layer. 1801 */ 1802 static void 1803 kmem_slab_free(kmem_cache_t *cp, void *buf) 1804 { 1805 kmem_slab_t *sp; 1806 kmem_bufctl_t *bcp, **prev_bcpp; 1807 1808 ASSERT(buf != NULL); 1809 1810 mutex_enter(&cp->cache_lock); 1811 cp->cache_slab_free++; 1812 1813 if (cp->cache_flags & KMF_HASH) { 1814 /* 1815 * Look up buffer in allocated-address hash table. 1816 */ 1817 prev_bcpp = KMEM_HASH(cp, buf); 1818 while ((bcp = *prev_bcpp) != NULL) { 1819 if (bcp->bc_addr == buf) { 1820 *prev_bcpp = bcp->bc_next; 1821 sp = bcp->bc_slab; 1822 break; 1823 } 1824 cp->cache_lookup_depth++; 1825 prev_bcpp = &bcp->bc_next; 1826 } 1827 } else { 1828 bcp = KMEM_BUFCTL(cp, buf); 1829 sp = KMEM_SLAB(cp, buf); 1830 } 1831 1832 if (bcp == NULL || sp->slab_cache != cp || !KMEM_SLAB_MEMBER(sp, buf)) { 1833 mutex_exit(&cp->cache_lock); 1834 kmem_error(KMERR_BADADDR, cp, buf); 1835 return; 1836 } 1837 1838 if (KMEM_SLAB_OFFSET(sp, buf) == sp->slab_stuck_offset) { 1839 /* 1840 * If this is the buffer that prevented the consolidator from 1841 * clearing the slab, we can reset the slab flags now that the 1842 * buffer is freed. (It makes sense to do this in 1843 * kmem_cache_free(), where the client gives up ownership of the 1844 * buffer, but on the hot path the test is too expensive.) 1845 */ 1846 kmem_slab_move_yes(cp, sp, buf); 1847 } 1848 1849 if ((cp->cache_flags & (KMF_AUDIT | KMF_BUFTAG)) == KMF_AUDIT) { 1850 if (cp->cache_flags & KMF_CONTENTS) 1851 ((kmem_bufctl_audit_t *)bcp)->bc_contents = 1852 kmem_log_enter(kmem_content_log, buf, 1853 cp->cache_contents); 1854 KMEM_AUDIT(kmem_transaction_log, cp, bcp); 1855 } 1856 1857 bcp->bc_next = sp->slab_head; 1858 sp->slab_head = bcp; 1859 1860 cp->cache_bufslab++; 1861 ASSERT(sp->slab_refcnt >= 1); 1862 1863 if (--sp->slab_refcnt == 0) { 1864 /* 1865 * There are no outstanding allocations from this slab, 1866 * so we can reclaim the memory. 1867 */ 1868 if (sp->slab_chunks == 1) { 1869 list_remove(&cp->cache_complete_slabs, sp); 1870 cp->cache_complete_slab_count--; 1871 } else { 1872 avl_remove(&cp->cache_partial_slabs, sp); 1873 } 1874 1875 cp->cache_buftotal -= sp->slab_chunks; 1876 cp->cache_bufslab -= sp->slab_chunks; 1877 /* 1878 * Defer releasing the slab to the virtual memory subsystem 1879 * while there is a pending move callback, since we guarantee 1880 * that buffers passed to the move callback have only been 1881 * touched by kmem or by the client itself. Since the memory 1882 * patterns baddcafe (uninitialized) and deadbeef (freed) both 1883 * set at least one of the two lowest order bits, the client can 1884 * test those bits in the move callback to determine whether or 1885 * not it knows about the buffer (assuming that the client also 1886 * sets one of those low order bits whenever it frees a buffer). 1887 */ 1888 if (cp->cache_defrag == NULL || 1889 (avl_is_empty(&cp->cache_defrag->kmd_moves_pending) && 1890 !(sp->slab_flags & KMEM_SLAB_MOVE_PENDING))) { 1891 cp->cache_slab_destroy++; 1892 mutex_exit(&cp->cache_lock); 1893 kmem_slab_destroy(cp, sp); 1894 } else { 1895 list_t *deadlist = &cp->cache_defrag->kmd_deadlist; 1896 /* 1897 * Slabs are inserted at both ends of the deadlist to 1898 * distinguish between slabs freed while move callbacks 1899 * are pending (list head) and a slab freed while the 1900 * lock is dropped in kmem_move_buffers() (list tail) so 1901 * that in both cases slab_destroy() is called from the 1902 * right context. 1903 */ 1904 if (sp->slab_flags & KMEM_SLAB_MOVE_PENDING) { 1905 list_insert_tail(deadlist, sp); 1906 } else { 1907 list_insert_head(deadlist, sp); 1908 } 1909 cp->cache_defrag->kmd_deadcount++; 1910 mutex_exit(&cp->cache_lock); 1911 } 1912 return; 1913 } 1914 1915 if (bcp->bc_next == NULL) { 1916 /* Transition the slab from completely allocated to partial. */ 1917 ASSERT(sp->slab_refcnt == (sp->slab_chunks - 1)); 1918 ASSERT(sp->slab_chunks > 1); 1919 list_remove(&cp->cache_complete_slabs, sp); 1920 cp->cache_complete_slab_count--; 1921 avl_add(&cp->cache_partial_slabs, sp); 1922 } else { 1923 #ifdef DEBUG 1924 if (avl_update_gt(&cp->cache_partial_slabs, sp)) { 1925 KMEM_STAT_ADD(kmem_move_stats.kms_avl_update); 1926 } else { 1927 KMEM_STAT_ADD(kmem_move_stats.kms_avl_noupdate); 1928 } 1929 #else 1930 (void) avl_update_gt(&cp->cache_partial_slabs, sp); 1931 #endif 1932 } 1933 1934 ASSERT((cp->cache_slab_create - cp->cache_slab_destroy) == 1935 (cp->cache_complete_slab_count + 1936 avl_numnodes(&cp->cache_partial_slabs) + 1937 (cp->cache_defrag == NULL ? 0 : cp->cache_defrag->kmd_deadcount))); 1938 mutex_exit(&cp->cache_lock); 1939 } 1940 1941 /* 1942 * Return -1 if kmem_error, 1 if constructor fails, 0 if successful. 1943 */ 1944 static int 1945 kmem_cache_alloc_debug(kmem_cache_t *cp, void *buf, int kmflag, int construct, 1946 caddr_t caller) 1947 { 1948 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 1949 kmem_bufctl_audit_t *bcp = (kmem_bufctl_audit_t *)btp->bt_bufctl; 1950 uint32_t mtbf; 1951 1952 if (btp->bt_bxstat != ((intptr_t)bcp ^ KMEM_BUFTAG_FREE)) { 1953 kmem_error(KMERR_BADBUFTAG, cp, buf); 1954 return (-1); 1955 } 1956 1957 btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_ALLOC; 1958 1959 if ((cp->cache_flags & KMF_HASH) && bcp->bc_addr != buf) { 1960 kmem_error(KMERR_BADBUFCTL, cp, buf); 1961 return (-1); 1962 } 1963 1964 if (cp->cache_flags & KMF_DEADBEEF) { 1965 if (!construct && (cp->cache_flags & KMF_LITE)) { 1966 if (*(uint64_t *)buf != KMEM_FREE_PATTERN) { 1967 kmem_error(KMERR_MODIFIED, cp, buf); 1968 return (-1); 1969 } 1970 if (cp->cache_constructor != NULL) 1971 *(uint64_t *)buf = btp->bt_redzone; 1972 else 1973 *(uint64_t *)buf = KMEM_UNINITIALIZED_PATTERN; 1974 } else { 1975 construct = 1; 1976 if (verify_and_copy_pattern(KMEM_FREE_PATTERN, 1977 KMEM_UNINITIALIZED_PATTERN, buf, 1978 cp->cache_verify)) { 1979 kmem_error(KMERR_MODIFIED, cp, buf); 1980 return (-1); 1981 } 1982 } 1983 } 1984 btp->bt_redzone = KMEM_REDZONE_PATTERN; 1985 1986 if ((mtbf = kmem_mtbf | cp->cache_mtbf) != 0 && 1987 gethrtime() % mtbf == 0 && 1988 (kmflag & (KM_NOSLEEP | KM_PANIC)) == KM_NOSLEEP) { 1989 kmem_log_event(kmem_failure_log, cp, NULL, NULL); 1990 if (!construct && cp->cache_destructor != NULL) 1991 cp->cache_destructor(buf, cp->cache_private); 1992 } else { 1993 mtbf = 0; 1994 } 1995 1996 if (mtbf || (construct && cp->cache_constructor != NULL && 1997 cp->cache_constructor(buf, cp->cache_private, kmflag) != 0)) { 1998 atomic_inc_64(&cp->cache_alloc_fail); 1999 btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE; 2000 if (cp->cache_flags & KMF_DEADBEEF) 2001 copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify); 2002 kmem_slab_free(cp, buf); 2003 return (1); 2004 } 2005 2006 if (cp->cache_flags & KMF_AUDIT) { 2007 KMEM_AUDIT(kmem_transaction_log, cp, bcp); 2008 } 2009 2010 if ((cp->cache_flags & KMF_LITE) && 2011 !(cp->cache_cflags & KMC_KMEM_ALLOC)) { 2012 KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller); 2013 } 2014 2015 return (0); 2016 } 2017 2018 static int 2019 kmem_cache_free_debug(kmem_cache_t *cp, void *buf, caddr_t caller) 2020 { 2021 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2022 kmem_bufctl_audit_t *bcp = (kmem_bufctl_audit_t *)btp->bt_bufctl; 2023 kmem_slab_t *sp; 2024 2025 if (btp->bt_bxstat != ((intptr_t)bcp ^ KMEM_BUFTAG_ALLOC)) { 2026 if (btp->bt_bxstat == ((intptr_t)bcp ^ KMEM_BUFTAG_FREE)) { 2027 kmem_error(KMERR_DUPFREE, cp, buf); 2028 return (-1); 2029 } 2030 sp = kmem_findslab(cp, buf); 2031 if (sp == NULL || sp->slab_cache != cp) 2032 kmem_error(KMERR_BADADDR, cp, buf); 2033 else 2034 kmem_error(KMERR_REDZONE, cp, buf); 2035 return (-1); 2036 } 2037 2038 btp->bt_bxstat = (intptr_t)bcp ^ KMEM_BUFTAG_FREE; 2039 2040 if ((cp->cache_flags & KMF_HASH) && bcp->bc_addr != buf) { 2041 kmem_error(KMERR_BADBUFCTL, cp, buf); 2042 return (-1); 2043 } 2044 2045 if (btp->bt_redzone != KMEM_REDZONE_PATTERN) { 2046 kmem_error(KMERR_REDZONE, cp, buf); 2047 return (-1); 2048 } 2049 2050 if (cp->cache_flags & KMF_AUDIT) { 2051 if (cp->cache_flags & KMF_CONTENTS) 2052 bcp->bc_contents = kmem_log_enter(kmem_content_log, 2053 buf, cp->cache_contents); 2054 KMEM_AUDIT(kmem_transaction_log, cp, bcp); 2055 } 2056 2057 if ((cp->cache_flags & KMF_LITE) && 2058 !(cp->cache_cflags & KMC_KMEM_ALLOC)) { 2059 KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller); 2060 } 2061 2062 if (cp->cache_flags & KMF_DEADBEEF) { 2063 if (cp->cache_flags & KMF_LITE) 2064 btp->bt_redzone = *(uint64_t *)buf; 2065 else if (cp->cache_destructor != NULL) 2066 cp->cache_destructor(buf, cp->cache_private); 2067 2068 copy_pattern(KMEM_FREE_PATTERN, buf, cp->cache_verify); 2069 } 2070 2071 return (0); 2072 } 2073 2074 /* 2075 * Free each object in magazine mp to cp's slab layer, and free mp itself. 2076 */ 2077 static void 2078 kmem_magazine_destroy(kmem_cache_t *cp, kmem_magazine_t *mp, int nrounds) 2079 { 2080 int round; 2081 2082 ASSERT(!list_link_active(&cp->cache_link) || 2083 taskq_member(kmem_taskq, curthread)); 2084 2085 for (round = 0; round < nrounds; round++) { 2086 void *buf = mp->mag_round[round]; 2087 2088 if (cp->cache_flags & KMF_DEADBEEF) { 2089 if (verify_pattern(KMEM_FREE_PATTERN, buf, 2090 cp->cache_verify) != NULL) { 2091 kmem_error(KMERR_MODIFIED, cp, buf); 2092 continue; 2093 } 2094 if ((cp->cache_flags & KMF_LITE) && 2095 cp->cache_destructor != NULL) { 2096 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2097 *(uint64_t *)buf = btp->bt_redzone; 2098 cp->cache_destructor(buf, cp->cache_private); 2099 *(uint64_t *)buf = KMEM_FREE_PATTERN; 2100 } 2101 } else if (cp->cache_destructor != NULL) { 2102 cp->cache_destructor(buf, cp->cache_private); 2103 } 2104 2105 kmem_slab_free(cp, buf); 2106 } 2107 ASSERT(KMEM_MAGAZINE_VALID(cp, mp)); 2108 kmem_cache_free(cp->cache_magtype->mt_cache, mp); 2109 } 2110 2111 /* 2112 * Allocate a magazine from the depot. 2113 */ 2114 static kmem_magazine_t * 2115 kmem_depot_alloc(kmem_cache_t *cp, kmem_maglist_t *mlp) 2116 { 2117 kmem_magazine_t *mp; 2118 2119 /* 2120 * If we can't get the depot lock without contention, 2121 * update our contention count. We use the depot 2122 * contention rate to determine whether we need to 2123 * increase the magazine size for better scalability. 2124 */ 2125 if (!mutex_tryenter(&cp->cache_depot_lock)) { 2126 mutex_enter(&cp->cache_depot_lock); 2127 cp->cache_depot_contention++; 2128 } 2129 2130 if ((mp = mlp->ml_list) != NULL) { 2131 ASSERT(KMEM_MAGAZINE_VALID(cp, mp)); 2132 mlp->ml_list = mp->mag_next; 2133 if (--mlp->ml_total < mlp->ml_min) 2134 mlp->ml_min = mlp->ml_total; 2135 mlp->ml_alloc++; 2136 } 2137 2138 mutex_exit(&cp->cache_depot_lock); 2139 2140 return (mp); 2141 } 2142 2143 /* 2144 * Free a magazine to the depot. 2145 */ 2146 static void 2147 kmem_depot_free(kmem_cache_t *cp, kmem_maglist_t *mlp, kmem_magazine_t *mp) 2148 { 2149 mutex_enter(&cp->cache_depot_lock); 2150 ASSERT(KMEM_MAGAZINE_VALID(cp, mp)); 2151 mp->mag_next = mlp->ml_list; 2152 mlp->ml_list = mp; 2153 mlp->ml_total++; 2154 mutex_exit(&cp->cache_depot_lock); 2155 } 2156 2157 /* 2158 * Update the working set statistics for cp's depot. 2159 */ 2160 static void 2161 kmem_depot_ws_update(kmem_cache_t *cp) 2162 { 2163 mutex_enter(&cp->cache_depot_lock); 2164 cp->cache_full.ml_reaplimit = cp->cache_full.ml_min; 2165 cp->cache_full.ml_min = cp->cache_full.ml_total; 2166 cp->cache_empty.ml_reaplimit = cp->cache_empty.ml_min; 2167 cp->cache_empty.ml_min = cp->cache_empty.ml_total; 2168 mutex_exit(&cp->cache_depot_lock); 2169 } 2170 2171 /* 2172 * Reap all magazines that have fallen out of the depot's working set. 2173 */ 2174 static void 2175 kmem_depot_ws_reap(kmem_cache_t *cp) 2176 { 2177 long reap; 2178 kmem_magazine_t *mp; 2179 2180 ASSERT(!list_link_active(&cp->cache_link) || 2181 taskq_member(kmem_taskq, curthread)); 2182 2183 reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min); 2184 while (reap-- && (mp = kmem_depot_alloc(cp, &cp->cache_full)) != NULL) 2185 kmem_magazine_destroy(cp, mp, cp->cache_magtype->mt_magsize); 2186 2187 reap = MIN(cp->cache_empty.ml_reaplimit, cp->cache_empty.ml_min); 2188 while (reap-- && (mp = kmem_depot_alloc(cp, &cp->cache_empty)) != NULL) 2189 kmem_magazine_destroy(cp, mp, 0); 2190 } 2191 2192 static void 2193 kmem_cpu_reload(kmem_cpu_cache_t *ccp, kmem_magazine_t *mp, int rounds) 2194 { 2195 ASSERT((ccp->cc_loaded == NULL && ccp->cc_rounds == -1) || 2196 (ccp->cc_loaded && ccp->cc_rounds + rounds == ccp->cc_magsize)); 2197 ASSERT(ccp->cc_magsize > 0); 2198 2199 ccp->cc_ploaded = ccp->cc_loaded; 2200 ccp->cc_prounds = ccp->cc_rounds; 2201 ccp->cc_loaded = mp; 2202 ccp->cc_rounds = rounds; 2203 } 2204 2205 /* 2206 * Intercept kmem alloc/free calls during crash dump in order to avoid 2207 * changing kmem state while memory is being saved to the dump device. 2208 * Otherwise, ::kmem_verify will report "corrupt buffers". Note that 2209 * there are no locks because only one CPU calls kmem during a crash 2210 * dump. To enable this feature, first create the associated vmem 2211 * arena with VMC_DUMPSAFE. 2212 */ 2213 static void *kmem_dump_start; /* start of pre-reserved heap */ 2214 static void *kmem_dump_end; /* end of heap area */ 2215 static void *kmem_dump_curr; /* current free heap pointer */ 2216 static size_t kmem_dump_size; /* size of heap area */ 2217 2218 /* append to each buf created in the pre-reserved heap */ 2219 typedef struct kmem_dumpctl { 2220 void *kdc_next; /* cache dump free list linkage */ 2221 } kmem_dumpctl_t; 2222 2223 #define KMEM_DUMPCTL(cp, buf) \ 2224 ((kmem_dumpctl_t *)P2ROUNDUP((uintptr_t)(buf) + (cp)->cache_bufsize, \ 2225 sizeof (void *))) 2226 2227 /* Keep some simple stats. */ 2228 #define KMEM_DUMP_LOGS (100) 2229 2230 typedef struct kmem_dump_log { 2231 kmem_cache_t *kdl_cache; 2232 uint_t kdl_allocs; /* # of dump allocations */ 2233 uint_t kdl_frees; /* # of dump frees */ 2234 uint_t kdl_alloc_fails; /* # of allocation failures */ 2235 uint_t kdl_free_nondump; /* # of non-dump frees */ 2236 uint_t kdl_unsafe; /* cache was used, but unsafe */ 2237 } kmem_dump_log_t; 2238 2239 static kmem_dump_log_t *kmem_dump_log; 2240 static int kmem_dump_log_idx; 2241 2242 #define KDI_LOG(cp, stat) { \ 2243 kmem_dump_log_t *kdl; \ 2244 if ((kdl = (kmem_dump_log_t *)((cp)->cache_dumplog)) != NULL) { \ 2245 kdl->stat++; \ 2246 } else if (kmem_dump_log_idx < KMEM_DUMP_LOGS) { \ 2247 kdl = &kmem_dump_log[kmem_dump_log_idx++]; \ 2248 kdl->stat++; \ 2249 kdl->kdl_cache = (cp); \ 2250 (cp)->cache_dumplog = kdl; \ 2251 } \ 2252 } 2253 2254 /* set non zero for full report */ 2255 uint_t kmem_dump_verbose = 0; 2256 2257 /* stats for overize heap */ 2258 uint_t kmem_dump_oversize_allocs = 0; 2259 uint_t kmem_dump_oversize_max = 0; 2260 2261 static void 2262 kmem_dumppr(char **pp, char *e, const char *format, ...) 2263 { 2264 char *p = *pp; 2265 2266 if (p < e) { 2267 int n; 2268 va_list ap; 2269 2270 va_start(ap, format); 2271 n = vsnprintf(p, e - p, format, ap); 2272 va_end(ap); 2273 *pp = p + n; 2274 } 2275 } 2276 2277 /* 2278 * Called when dumpadm(1M) configures dump parameters. 2279 */ 2280 void 2281 kmem_dump_init(size_t size) 2282 { 2283 if (kmem_dump_start != NULL) 2284 kmem_free(kmem_dump_start, kmem_dump_size); 2285 2286 if (kmem_dump_log == NULL) 2287 kmem_dump_log = (kmem_dump_log_t *)kmem_zalloc(KMEM_DUMP_LOGS * 2288 sizeof (kmem_dump_log_t), KM_SLEEP); 2289 2290 kmem_dump_start = kmem_alloc(size, KM_SLEEP); 2291 2292 if (kmem_dump_start != NULL) { 2293 kmem_dump_size = size; 2294 kmem_dump_curr = kmem_dump_start; 2295 kmem_dump_end = (void *)((char *)kmem_dump_start + size); 2296 copy_pattern(KMEM_UNINITIALIZED_PATTERN, kmem_dump_start, size); 2297 } else { 2298 kmem_dump_size = 0; 2299 kmem_dump_curr = NULL; 2300 kmem_dump_end = NULL; 2301 } 2302 } 2303 2304 /* 2305 * Set flag for each kmem_cache_t if is safe to use alternate dump 2306 * memory. Called just before panic crash dump starts. Set the flag 2307 * for the calling CPU. 2308 */ 2309 void 2310 kmem_dump_begin(void) 2311 { 2312 ASSERT(panicstr != NULL); 2313 if (kmem_dump_start != NULL) { 2314 kmem_cache_t *cp; 2315 2316 for (cp = list_head(&kmem_caches); cp != NULL; 2317 cp = list_next(&kmem_caches, cp)) { 2318 kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp); 2319 2320 if (cp->cache_arena->vm_cflags & VMC_DUMPSAFE) { 2321 cp->cache_flags |= KMF_DUMPDIVERT; 2322 ccp->cc_flags |= KMF_DUMPDIVERT; 2323 ccp->cc_dump_rounds = ccp->cc_rounds; 2324 ccp->cc_dump_prounds = ccp->cc_prounds; 2325 ccp->cc_rounds = ccp->cc_prounds = -1; 2326 } else { 2327 cp->cache_flags |= KMF_DUMPUNSAFE; 2328 ccp->cc_flags |= KMF_DUMPUNSAFE; 2329 } 2330 } 2331 } 2332 } 2333 2334 /* 2335 * finished dump intercept 2336 * print any warnings on the console 2337 * return verbose information to dumpsys() in the given buffer 2338 */ 2339 size_t 2340 kmem_dump_finish(char *buf, size_t size) 2341 { 2342 int kdi_idx; 2343 int kdi_end = kmem_dump_log_idx; 2344 int percent = 0; 2345 int header = 0; 2346 int warn = 0; 2347 size_t used; 2348 kmem_cache_t *cp; 2349 kmem_dump_log_t *kdl; 2350 char *e = buf + size; 2351 char *p = buf; 2352 2353 if (kmem_dump_size == 0 || kmem_dump_verbose == 0) 2354 return (0); 2355 2356 used = (char *)kmem_dump_curr - (char *)kmem_dump_start; 2357 percent = (used * 100) / kmem_dump_size; 2358 2359 kmem_dumppr(&p, e, "%% heap used,%d\n", percent); 2360 kmem_dumppr(&p, e, "used bytes,%ld\n", used); 2361 kmem_dumppr(&p, e, "heap size,%ld\n", kmem_dump_size); 2362 kmem_dumppr(&p, e, "Oversize allocs,%d\n", 2363 kmem_dump_oversize_allocs); 2364 kmem_dumppr(&p, e, "Oversize max size,%ld\n", 2365 kmem_dump_oversize_max); 2366 2367 for (kdi_idx = 0; kdi_idx < kdi_end; kdi_idx++) { 2368 kdl = &kmem_dump_log[kdi_idx]; 2369 cp = kdl->kdl_cache; 2370 if (cp == NULL) 2371 break; 2372 if (kdl->kdl_alloc_fails) 2373 ++warn; 2374 if (header == 0) { 2375 kmem_dumppr(&p, e, 2376 "Cache Name,Allocs,Frees,Alloc Fails," 2377 "Nondump Frees,Unsafe Allocs/Frees\n"); 2378 header = 1; 2379 } 2380 kmem_dumppr(&p, e, "%s,%d,%d,%d,%d,%d\n", 2381 cp->cache_name, kdl->kdl_allocs, kdl->kdl_frees, 2382 kdl->kdl_alloc_fails, kdl->kdl_free_nondump, 2383 kdl->kdl_unsafe); 2384 } 2385 2386 /* return buffer size used */ 2387 if (p < e) 2388 bzero(p, e - p); 2389 return (p - buf); 2390 } 2391 2392 /* 2393 * Allocate a constructed object from alternate dump memory. 2394 */ 2395 void * 2396 kmem_cache_alloc_dump(kmem_cache_t *cp, int kmflag) 2397 { 2398 void *buf; 2399 void *curr; 2400 char *bufend; 2401 2402 /* return a constructed object */ 2403 if ((buf = cp->cache_dumpfreelist) != NULL) { 2404 cp->cache_dumpfreelist = KMEM_DUMPCTL(cp, buf)->kdc_next; 2405 KDI_LOG(cp, kdl_allocs); 2406 return (buf); 2407 } 2408 2409 /* create a new constructed object */ 2410 curr = kmem_dump_curr; 2411 buf = (void *)P2ROUNDUP((uintptr_t)curr, cp->cache_align); 2412 bufend = (char *)KMEM_DUMPCTL(cp, buf) + sizeof (kmem_dumpctl_t); 2413 2414 /* hat layer objects cannot cross a page boundary */ 2415 if (cp->cache_align < PAGESIZE) { 2416 char *page = (char *)P2ROUNDUP((uintptr_t)buf, PAGESIZE); 2417 if (bufend > page) { 2418 bufend += page - (char *)buf; 2419 buf = (void *)page; 2420 } 2421 } 2422 2423 /* fall back to normal alloc if reserved area is used up */ 2424 if (bufend > (char *)kmem_dump_end) { 2425 kmem_dump_curr = kmem_dump_end; 2426 KDI_LOG(cp, kdl_alloc_fails); 2427 return (NULL); 2428 } 2429 2430 /* 2431 * Must advance curr pointer before calling a constructor that 2432 * may also allocate memory. 2433 */ 2434 kmem_dump_curr = bufend; 2435 2436 /* run constructor */ 2437 if (cp->cache_constructor != NULL && 2438 cp->cache_constructor(buf, cp->cache_private, kmflag) 2439 != 0) { 2440 #ifdef DEBUG 2441 printf("name='%s' cache=0x%p: kmem cache constructor failed\n", 2442 cp->cache_name, (void *)cp); 2443 #endif 2444 /* reset curr pointer iff no allocs were done */ 2445 if (kmem_dump_curr == bufend) 2446 kmem_dump_curr = curr; 2447 2448 /* fall back to normal alloc if the constructor fails */ 2449 KDI_LOG(cp, kdl_alloc_fails); 2450 return (NULL); 2451 } 2452 2453 KDI_LOG(cp, kdl_allocs); 2454 return (buf); 2455 } 2456 2457 /* 2458 * Free a constructed object in alternate dump memory. 2459 */ 2460 int 2461 kmem_cache_free_dump(kmem_cache_t *cp, void *buf) 2462 { 2463 /* save constructed buffers for next time */ 2464 if ((char *)buf >= (char *)kmem_dump_start && 2465 (char *)buf < (char *)kmem_dump_end) { 2466 KMEM_DUMPCTL(cp, buf)->kdc_next = cp->cache_dumpfreelist; 2467 cp->cache_dumpfreelist = buf; 2468 KDI_LOG(cp, kdl_frees); 2469 return (0); 2470 } 2471 2472 /* count all non-dump buf frees */ 2473 KDI_LOG(cp, kdl_free_nondump); 2474 2475 /* just drop buffers that were allocated before dump started */ 2476 if (kmem_dump_curr < kmem_dump_end) 2477 return (0); 2478 2479 /* fall back to normal free if reserved area is used up */ 2480 return (1); 2481 } 2482 2483 /* 2484 * Allocate a constructed object from cache cp. 2485 */ 2486 void * 2487 kmem_cache_alloc(kmem_cache_t *cp, int kmflag) 2488 { 2489 kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp); 2490 kmem_magazine_t *fmp; 2491 void *buf; 2492 2493 mutex_enter(&ccp->cc_lock); 2494 for (;;) { 2495 /* 2496 * If there's an object available in the current CPU's 2497 * loaded magazine, just take it and return. 2498 */ 2499 if (ccp->cc_rounds > 0) { 2500 buf = ccp->cc_loaded->mag_round[--ccp->cc_rounds]; 2501 ccp->cc_alloc++; 2502 mutex_exit(&ccp->cc_lock); 2503 if (ccp->cc_flags & (KMF_BUFTAG | KMF_DUMPUNSAFE)) { 2504 if (ccp->cc_flags & KMF_DUMPUNSAFE) { 2505 ASSERT(!(ccp->cc_flags & 2506 KMF_DUMPDIVERT)); 2507 KDI_LOG(cp, kdl_unsafe); 2508 } 2509 if ((ccp->cc_flags & KMF_BUFTAG) && 2510 kmem_cache_alloc_debug(cp, buf, kmflag, 0, 2511 caller()) != 0) { 2512 if (kmflag & KM_NOSLEEP) 2513 return (NULL); 2514 mutex_enter(&ccp->cc_lock); 2515 continue; 2516 } 2517 } 2518 return (buf); 2519 } 2520 2521 /* 2522 * The loaded magazine is empty. If the previously loaded 2523 * magazine was full, exchange them and try again. 2524 */ 2525 if (ccp->cc_prounds > 0) { 2526 kmem_cpu_reload(ccp, ccp->cc_ploaded, ccp->cc_prounds); 2527 continue; 2528 } 2529 2530 /* 2531 * Return an alternate buffer at dump time to preserve 2532 * the heap. 2533 */ 2534 if (ccp->cc_flags & (KMF_DUMPDIVERT | KMF_DUMPUNSAFE)) { 2535 if (ccp->cc_flags & KMF_DUMPUNSAFE) { 2536 ASSERT(!(ccp->cc_flags & KMF_DUMPDIVERT)); 2537 /* log it so that we can warn about it */ 2538 KDI_LOG(cp, kdl_unsafe); 2539 } else { 2540 if ((buf = kmem_cache_alloc_dump(cp, kmflag)) != 2541 NULL) { 2542 mutex_exit(&ccp->cc_lock); 2543 return (buf); 2544 } 2545 break; /* fall back to slab layer */ 2546 } 2547 } 2548 2549 /* 2550 * If the magazine layer is disabled, break out now. 2551 */ 2552 if (ccp->cc_magsize == 0) 2553 break; 2554 2555 /* 2556 * Try to get a full magazine from the depot. 2557 */ 2558 fmp = kmem_depot_alloc(cp, &cp->cache_full); 2559 if (fmp != NULL) { 2560 if (ccp->cc_ploaded != NULL) 2561 kmem_depot_free(cp, &cp->cache_empty, 2562 ccp->cc_ploaded); 2563 kmem_cpu_reload(ccp, fmp, ccp->cc_magsize); 2564 continue; 2565 } 2566 2567 /* 2568 * There are no full magazines in the depot, 2569 * so fall through to the slab layer. 2570 */ 2571 break; 2572 } 2573 mutex_exit(&ccp->cc_lock); 2574 2575 /* 2576 * We couldn't allocate a constructed object from the magazine layer, 2577 * so get a raw buffer from the slab layer and apply its constructor. 2578 */ 2579 buf = kmem_slab_alloc(cp, kmflag); 2580 2581 if (buf == NULL) 2582 return (NULL); 2583 2584 if (cp->cache_flags & KMF_BUFTAG) { 2585 /* 2586 * Make kmem_cache_alloc_debug() apply the constructor for us. 2587 */ 2588 int rc = kmem_cache_alloc_debug(cp, buf, kmflag, 1, caller()); 2589 if (rc != 0) { 2590 if (kmflag & KM_NOSLEEP) 2591 return (NULL); 2592 /* 2593 * kmem_cache_alloc_debug() detected corruption 2594 * but didn't panic (kmem_panic <= 0). We should not be 2595 * here because the constructor failed (indicated by a 2596 * return code of 1). Try again. 2597 */ 2598 ASSERT(rc == -1); 2599 return (kmem_cache_alloc(cp, kmflag)); 2600 } 2601 return (buf); 2602 } 2603 2604 if (cp->cache_constructor != NULL && 2605 cp->cache_constructor(buf, cp->cache_private, kmflag) != 0) { 2606 atomic_inc_64(&cp->cache_alloc_fail); 2607 kmem_slab_free(cp, buf); 2608 return (NULL); 2609 } 2610 2611 return (buf); 2612 } 2613 2614 /* 2615 * The freed argument tells whether or not kmem_cache_free_debug() has already 2616 * been called so that we can avoid the duplicate free error. For example, a 2617 * buffer on a magazine has already been freed by the client but is still 2618 * constructed. 2619 */ 2620 static void 2621 kmem_slab_free_constructed(kmem_cache_t *cp, void *buf, boolean_t freed) 2622 { 2623 if (!freed && (cp->cache_flags & KMF_BUFTAG)) 2624 if (kmem_cache_free_debug(cp, buf, caller()) == -1) 2625 return; 2626 2627 /* 2628 * Note that if KMF_DEADBEEF is in effect and KMF_LITE is not, 2629 * kmem_cache_free_debug() will have already applied the destructor. 2630 */ 2631 if ((cp->cache_flags & (KMF_DEADBEEF | KMF_LITE)) != KMF_DEADBEEF && 2632 cp->cache_destructor != NULL) { 2633 if (cp->cache_flags & KMF_DEADBEEF) { /* KMF_LITE implied */ 2634 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2635 *(uint64_t *)buf = btp->bt_redzone; 2636 cp->cache_destructor(buf, cp->cache_private); 2637 *(uint64_t *)buf = KMEM_FREE_PATTERN; 2638 } else { 2639 cp->cache_destructor(buf, cp->cache_private); 2640 } 2641 } 2642 2643 kmem_slab_free(cp, buf); 2644 } 2645 2646 /* 2647 * Used when there's no room to free a buffer to the per-CPU cache. 2648 * Drops and re-acquires &ccp->cc_lock, and returns non-zero if the 2649 * caller should try freeing to the per-CPU cache again. 2650 * Note that we don't directly install the magazine in the cpu cache, 2651 * since its state may have changed wildly while the lock was dropped. 2652 */ 2653 static int 2654 kmem_cpucache_magazine_alloc(kmem_cpu_cache_t *ccp, kmem_cache_t *cp) 2655 { 2656 kmem_magazine_t *emp; 2657 kmem_magtype_t *mtp; 2658 2659 ASSERT(MUTEX_HELD(&ccp->cc_lock)); 2660 ASSERT(((uint_t)ccp->cc_rounds == ccp->cc_magsize || 2661 ((uint_t)ccp->cc_rounds == -1)) && 2662 ((uint_t)ccp->cc_prounds == ccp->cc_magsize || 2663 ((uint_t)ccp->cc_prounds == -1))); 2664 2665 emp = kmem_depot_alloc(cp, &cp->cache_empty); 2666 if (emp != NULL) { 2667 if (ccp->cc_ploaded != NULL) 2668 kmem_depot_free(cp, &cp->cache_full, 2669 ccp->cc_ploaded); 2670 kmem_cpu_reload(ccp, emp, 0); 2671 return (1); 2672 } 2673 /* 2674 * There are no empty magazines in the depot, 2675 * so try to allocate a new one. We must drop all locks 2676 * across kmem_cache_alloc() because lower layers may 2677 * attempt to allocate from this cache. 2678 */ 2679 mtp = cp->cache_magtype; 2680 mutex_exit(&ccp->cc_lock); 2681 emp = kmem_cache_alloc(mtp->mt_cache, KM_NOSLEEP); 2682 mutex_enter(&ccp->cc_lock); 2683 2684 if (emp != NULL) { 2685 /* 2686 * We successfully allocated an empty magazine. 2687 * However, we had to drop ccp->cc_lock to do it, 2688 * so the cache's magazine size may have changed. 2689 * If so, free the magazine and try again. 2690 */ 2691 if (ccp->cc_magsize != mtp->mt_magsize) { 2692 mutex_exit(&ccp->cc_lock); 2693 kmem_cache_free(mtp->mt_cache, emp); 2694 mutex_enter(&ccp->cc_lock); 2695 return (1); 2696 } 2697 2698 /* 2699 * We got a magazine of the right size. Add it to 2700 * the depot and try the whole dance again. 2701 */ 2702 kmem_depot_free(cp, &cp->cache_empty, emp); 2703 return (1); 2704 } 2705 2706 /* 2707 * We couldn't allocate an empty magazine, 2708 * so fall through to the slab layer. 2709 */ 2710 return (0); 2711 } 2712 2713 /* 2714 * Free a constructed object to cache cp. 2715 */ 2716 void 2717 kmem_cache_free(kmem_cache_t *cp, void *buf) 2718 { 2719 kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp); 2720 2721 /* 2722 * The client must not free either of the buffers passed to the move 2723 * callback function. 2724 */ 2725 ASSERT(cp->cache_defrag == NULL || 2726 cp->cache_defrag->kmd_thread != curthread || 2727 (buf != cp->cache_defrag->kmd_from_buf && 2728 buf != cp->cache_defrag->kmd_to_buf)); 2729 2730 if (ccp->cc_flags & (KMF_BUFTAG | KMF_DUMPDIVERT | KMF_DUMPUNSAFE)) { 2731 if (ccp->cc_flags & KMF_DUMPUNSAFE) { 2732 ASSERT(!(ccp->cc_flags & KMF_DUMPDIVERT)); 2733 /* log it so that we can warn about it */ 2734 KDI_LOG(cp, kdl_unsafe); 2735 } else if (KMEM_DUMPCC(ccp) && !kmem_cache_free_dump(cp, buf)) { 2736 return; 2737 } 2738 if (ccp->cc_flags & KMF_BUFTAG) { 2739 if (kmem_cache_free_debug(cp, buf, caller()) == -1) 2740 return; 2741 } 2742 } 2743 2744 mutex_enter(&ccp->cc_lock); 2745 /* 2746 * Any changes to this logic should be reflected in kmem_slab_prefill() 2747 */ 2748 for (;;) { 2749 /* 2750 * If there's a slot available in the current CPU's 2751 * loaded magazine, just put the object there and return. 2752 */ 2753 if ((uint_t)ccp->cc_rounds < ccp->cc_magsize) { 2754 ccp->cc_loaded->mag_round[ccp->cc_rounds++] = buf; 2755 ccp->cc_free++; 2756 mutex_exit(&ccp->cc_lock); 2757 return; 2758 } 2759 2760 /* 2761 * The loaded magazine is full. If the previously loaded 2762 * magazine was empty, exchange them and try again. 2763 */ 2764 if (ccp->cc_prounds == 0) { 2765 kmem_cpu_reload(ccp, ccp->cc_ploaded, ccp->cc_prounds); 2766 continue; 2767 } 2768 2769 /* 2770 * If the magazine layer is disabled, break out now. 2771 */ 2772 if (ccp->cc_magsize == 0) 2773 break; 2774 2775 if (!kmem_cpucache_magazine_alloc(ccp, cp)) { 2776 /* 2777 * We couldn't free our constructed object to the 2778 * magazine layer, so apply its destructor and free it 2779 * to the slab layer. 2780 */ 2781 break; 2782 } 2783 } 2784 mutex_exit(&ccp->cc_lock); 2785 kmem_slab_free_constructed(cp, buf, B_TRUE); 2786 } 2787 2788 static void 2789 kmem_slab_prefill(kmem_cache_t *cp, kmem_slab_t *sp) 2790 { 2791 kmem_cpu_cache_t *ccp = KMEM_CPU_CACHE(cp); 2792 int cache_flags = cp->cache_flags; 2793 2794 kmem_bufctl_t *next, *head; 2795 size_t nbufs; 2796 2797 /* 2798 * Completely allocate the newly created slab and put the pre-allocated 2799 * buffers in magazines. Any of the buffers that cannot be put in 2800 * magazines must be returned to the slab. 2801 */ 2802 ASSERT(MUTEX_HELD(&cp->cache_lock)); 2803 ASSERT((cache_flags & (KMF_PREFILL|KMF_BUFTAG)) == KMF_PREFILL); 2804 ASSERT(cp->cache_constructor == NULL); 2805 ASSERT(sp->slab_cache == cp); 2806 ASSERT(sp->slab_refcnt == 1); 2807 ASSERT(sp->slab_head != NULL && sp->slab_chunks > sp->slab_refcnt); 2808 ASSERT(avl_find(&cp->cache_partial_slabs, sp, NULL) == NULL); 2809 2810 head = sp->slab_head; 2811 nbufs = (sp->slab_chunks - sp->slab_refcnt); 2812 sp->slab_head = NULL; 2813 sp->slab_refcnt += nbufs; 2814 cp->cache_bufslab -= nbufs; 2815 cp->cache_slab_alloc += nbufs; 2816 list_insert_head(&cp->cache_complete_slabs, sp); 2817 cp->cache_complete_slab_count++; 2818 mutex_exit(&cp->cache_lock); 2819 mutex_enter(&ccp->cc_lock); 2820 2821 while (head != NULL) { 2822 void *buf = KMEM_BUF(cp, head); 2823 /* 2824 * If there's a slot available in the current CPU's 2825 * loaded magazine, just put the object there and 2826 * continue. 2827 */ 2828 if ((uint_t)ccp->cc_rounds < ccp->cc_magsize) { 2829 ccp->cc_loaded->mag_round[ccp->cc_rounds++] = 2830 buf; 2831 ccp->cc_free++; 2832 nbufs--; 2833 head = head->bc_next; 2834 continue; 2835 } 2836 2837 /* 2838 * The loaded magazine is full. If the previously 2839 * loaded magazine was empty, exchange them and try 2840 * again. 2841 */ 2842 if (ccp->cc_prounds == 0) { 2843 kmem_cpu_reload(ccp, ccp->cc_ploaded, 2844 ccp->cc_prounds); 2845 continue; 2846 } 2847 2848 /* 2849 * If the magazine layer is disabled, break out now. 2850 */ 2851 2852 if (ccp->cc_magsize == 0) { 2853 break; 2854 } 2855 2856 if (!kmem_cpucache_magazine_alloc(ccp, cp)) 2857 break; 2858 } 2859 mutex_exit(&ccp->cc_lock); 2860 if (nbufs != 0) { 2861 ASSERT(head != NULL); 2862 2863 /* 2864 * If there was a failure, return remaining objects to 2865 * the slab 2866 */ 2867 while (head != NULL) { 2868 ASSERT(nbufs != 0); 2869 next = head->bc_next; 2870 head->bc_next = NULL; 2871 kmem_slab_free(cp, KMEM_BUF(cp, head)); 2872 head = next; 2873 nbufs--; 2874 } 2875 } 2876 ASSERT(head == NULL); 2877 ASSERT(nbufs == 0); 2878 mutex_enter(&cp->cache_lock); 2879 } 2880 2881 void * 2882 kmem_zalloc(size_t size, int kmflag) 2883 { 2884 size_t index; 2885 void *buf; 2886 2887 if ((index = ((size - 1) >> KMEM_ALIGN_SHIFT)) < KMEM_ALLOC_TABLE_MAX) { 2888 kmem_cache_t *cp = kmem_alloc_table[index]; 2889 buf = kmem_cache_alloc(cp, kmflag); 2890 if (buf != NULL) { 2891 if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp)) { 2892 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2893 ((uint8_t *)buf)[size] = KMEM_REDZONE_BYTE; 2894 ((uint32_t *)btp)[1] = KMEM_SIZE_ENCODE(size); 2895 2896 if (cp->cache_flags & KMF_LITE) { 2897 KMEM_BUFTAG_LITE_ENTER(btp, 2898 kmem_lite_count, caller()); 2899 } 2900 } 2901 bzero(buf, size); 2902 } 2903 } else { 2904 buf = kmem_alloc(size, kmflag); 2905 if (buf != NULL) 2906 bzero(buf, size); 2907 } 2908 return (buf); 2909 } 2910 2911 void * 2912 kmem_alloc(size_t size, int kmflag) 2913 { 2914 size_t index; 2915 kmem_cache_t *cp; 2916 void *buf; 2917 2918 if ((index = ((size - 1) >> KMEM_ALIGN_SHIFT)) < KMEM_ALLOC_TABLE_MAX) { 2919 cp = kmem_alloc_table[index]; 2920 /* fall through to kmem_cache_alloc() */ 2921 2922 } else if ((index = ((size - 1) >> KMEM_BIG_SHIFT)) < 2923 kmem_big_alloc_table_max) { 2924 cp = kmem_big_alloc_table[index]; 2925 /* fall through to kmem_cache_alloc() */ 2926 2927 } else { 2928 if (size == 0) 2929 return (NULL); 2930 2931 buf = vmem_alloc(kmem_oversize_arena, size, 2932 kmflag & KM_VMFLAGS); 2933 if (buf == NULL) 2934 kmem_log_event(kmem_failure_log, NULL, NULL, 2935 (void *)size); 2936 else if (KMEM_DUMP(kmem_slab_cache)) { 2937 /* stats for dump intercept */ 2938 kmem_dump_oversize_allocs++; 2939 if (size > kmem_dump_oversize_max) 2940 kmem_dump_oversize_max = size; 2941 } 2942 return (buf); 2943 } 2944 2945 buf = kmem_cache_alloc(cp, kmflag); 2946 if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp) && buf != NULL) { 2947 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2948 ((uint8_t *)buf)[size] = KMEM_REDZONE_BYTE; 2949 ((uint32_t *)btp)[1] = KMEM_SIZE_ENCODE(size); 2950 2951 if (cp->cache_flags & KMF_LITE) { 2952 KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, caller()); 2953 } 2954 } 2955 return (buf); 2956 } 2957 2958 void 2959 kmem_free(void *buf, size_t size) 2960 { 2961 size_t index; 2962 kmem_cache_t *cp; 2963 2964 if ((index = (size - 1) >> KMEM_ALIGN_SHIFT) < KMEM_ALLOC_TABLE_MAX) { 2965 cp = kmem_alloc_table[index]; 2966 /* fall through to kmem_cache_free() */ 2967 2968 } else if ((index = ((size - 1) >> KMEM_BIG_SHIFT)) < 2969 kmem_big_alloc_table_max) { 2970 cp = kmem_big_alloc_table[index]; 2971 /* fall through to kmem_cache_free() */ 2972 2973 } else { 2974 EQUIV(buf == NULL, size == 0); 2975 if (buf == NULL && size == 0) 2976 return; 2977 vmem_free(kmem_oversize_arena, buf, size); 2978 return; 2979 } 2980 2981 if ((cp->cache_flags & KMF_BUFTAG) && !KMEM_DUMP(cp)) { 2982 kmem_buftag_t *btp = KMEM_BUFTAG(cp, buf); 2983 uint32_t *ip = (uint32_t *)btp; 2984 if (ip[1] != KMEM_SIZE_ENCODE(size)) { 2985 if (*(uint64_t *)buf == KMEM_FREE_PATTERN) { 2986 kmem_error(KMERR_DUPFREE, cp, buf); 2987 return; 2988 } 2989 if (KMEM_SIZE_VALID(ip[1])) { 2990 ip[0] = KMEM_SIZE_ENCODE(size); 2991 kmem_error(KMERR_BADSIZE, cp, buf); 2992 } else { 2993 kmem_error(KMERR_REDZONE, cp, buf); 2994 } 2995 return; 2996 } 2997 if (((uint8_t *)buf)[size] != KMEM_REDZONE_BYTE) { 2998 kmem_error(KMERR_REDZONE, cp, buf); 2999 return; 3000 } 3001 btp->bt_redzone = KMEM_REDZONE_PATTERN; 3002 if (cp->cache_flags & KMF_LITE) { 3003 KMEM_BUFTAG_LITE_ENTER(btp, kmem_lite_count, 3004 caller()); 3005 } 3006 } 3007 kmem_cache_free(cp, buf); 3008 } 3009 3010 void * 3011 kmem_firewall_va_alloc(vmem_t *vmp, size_t size, int vmflag) 3012 { 3013 size_t realsize = size + vmp->vm_quantum; 3014 void *addr; 3015 3016 /* 3017 * Annoying edge case: if 'size' is just shy of ULONG_MAX, adding 3018 * vm_quantum will cause integer wraparound. Check for this, and 3019 * blow off the firewall page in this case. Note that such a 3020 * giant allocation (the entire kernel address space) can never 3021 * be satisfied, so it will either fail immediately (VM_NOSLEEP) 3022 * or sleep forever (VM_SLEEP). Thus, there is no need for a 3023 * corresponding check in kmem_firewall_va_free(). 3024 */ 3025 if (realsize < size) 3026 realsize = size; 3027 3028 /* 3029 * While boot still owns resource management, make sure that this 3030 * redzone virtual address allocation is properly accounted for in 3031 * OBPs "virtual-memory" "available" lists because we're 3032 * effectively claiming them for a red zone. If we don't do this, 3033 * the available lists become too fragmented and too large for the 3034 * current boot/kernel memory list interface. 3035 */ 3036 addr = vmem_alloc(vmp, realsize, vmflag | VM_NEXTFIT); 3037 3038 if (addr != NULL && kvseg.s_base == NULL && realsize != size) 3039 (void) boot_virt_alloc((char *)addr + size, vmp->vm_quantum); 3040 3041 return (addr); 3042 } 3043 3044 void 3045 kmem_firewall_va_free(vmem_t *vmp, void *addr, size_t size) 3046 { 3047 ASSERT((kvseg.s_base == NULL ? 3048 va_to_pfn((char *)addr + size) : 3049 hat_getpfnum(kas.a_hat, (caddr_t)addr + size)) == PFN_INVALID); 3050 3051 vmem_free(vmp, addr, size + vmp->vm_quantum); 3052 } 3053 3054 /* 3055 * Try to allocate at least `size' bytes of memory without sleeping or 3056 * panicking. Return actual allocated size in `asize'. If allocation failed, 3057 * try final allocation with sleep or panic allowed. 3058 */ 3059 void * 3060 kmem_alloc_tryhard(size_t size, size_t *asize, int kmflag) 3061 { 3062 void *p; 3063 3064 *asize = P2ROUNDUP(size, KMEM_ALIGN); 3065 do { 3066 p = kmem_alloc(*asize, (kmflag | KM_NOSLEEP) & ~KM_PANIC); 3067 if (p != NULL) 3068 return (p); 3069 *asize += KMEM_ALIGN; 3070 } while (*asize <= PAGESIZE); 3071 3072 *asize = P2ROUNDUP(size, KMEM_ALIGN); 3073 return (kmem_alloc(*asize, kmflag)); 3074 } 3075 3076 /* 3077 * Reclaim all unused memory from a cache. 3078 */ 3079 static void 3080 kmem_cache_reap(kmem_cache_t *cp) 3081 { 3082 ASSERT(taskq_member(kmem_taskq, curthread)); 3083 cp->cache_reap++; 3084 3085 /* 3086 * Ask the cache's owner to free some memory if possible. 3087 * The idea is to handle things like the inode cache, which 3088 * typically sits on a bunch of memory that it doesn't truly 3089 * *need*. Reclaim policy is entirely up to the owner; this 3090 * callback is just an advisory plea for help. 3091 */ 3092 if (cp->cache_reclaim != NULL) { 3093 long delta; 3094 3095 /* 3096 * Reclaimed memory should be reapable (not included in the 3097 * depot's working set). 3098 */ 3099 delta = cp->cache_full.ml_total; 3100 cp->cache_reclaim(cp->cache_private); 3101 delta = cp->cache_full.ml_total - delta; 3102 if (delta > 0) { 3103 mutex_enter(&cp->cache_depot_lock); 3104 cp->cache_full.ml_reaplimit += delta; 3105 cp->cache_full.ml_min += delta; 3106 mutex_exit(&cp->cache_depot_lock); 3107 } 3108 } 3109 3110 kmem_depot_ws_reap(cp); 3111 3112 if (cp->cache_defrag != NULL && !kmem_move_noreap) { 3113 kmem_cache_defrag(cp); 3114 } 3115 } 3116 3117 static void 3118 kmem_reap_timeout(void *flag_arg) 3119 { 3120 uint32_t *flag = (uint32_t *)flag_arg; 3121 3122 ASSERT(flag == &kmem_reaping || flag == &kmem_reaping_idspace); 3123 *flag = 0; 3124 } 3125 3126 static void 3127 kmem_reap_done(void *flag) 3128 { 3129 if (!callout_init_done) { 3130 /* can't schedule a timeout at this point */ 3131 kmem_reap_timeout(flag); 3132 } else { 3133 (void) timeout(kmem_reap_timeout, flag, kmem_reap_interval); 3134 } 3135 } 3136 3137 static void 3138 kmem_reap_start(void *flag) 3139 { 3140 ASSERT(flag == &kmem_reaping || flag == &kmem_reaping_idspace); 3141 3142 if (flag == &kmem_reaping) { 3143 kmem_cache_applyall(kmem_cache_reap, kmem_taskq, TQ_NOSLEEP); 3144 /* 3145 * if we have segkp under heap, reap segkp cache. 3146 */ 3147 if (segkp_fromheap) 3148 segkp_cache_free(); 3149 } 3150 else 3151 kmem_cache_applyall_id(kmem_cache_reap, kmem_taskq, TQ_NOSLEEP); 3152 3153 /* 3154 * We use taskq_dispatch() to schedule a timeout to clear 3155 * the flag so that kmem_reap() becomes self-throttling: 3156 * we won't reap again until the current reap completes *and* 3157 * at least kmem_reap_interval ticks have elapsed. 3158 */ 3159 if (!taskq_dispatch(kmem_taskq, kmem_reap_done, flag, TQ_NOSLEEP)) 3160 kmem_reap_done(flag); 3161 } 3162 3163 static void 3164 kmem_reap_common(void *flag_arg) 3165 { 3166 uint32_t *flag = (uint32_t *)flag_arg; 3167 3168 if (MUTEX_HELD(&kmem_cache_lock) || kmem_taskq == NULL || 3169 atomic_cas_32(flag, 0, 1) != 0) 3170 return; 3171 3172 /* 3173 * It may not be kosher to do memory allocation when a reap is called 3174 * is called (for example, if vmem_populate() is in the call chain). 3175 * So we start the reap going with a TQ_NOALLOC dispatch. If the 3176 * dispatch fails, we reset the flag, and the next reap will try again. 3177 */ 3178 if (!taskq_dispatch(kmem_taskq, kmem_reap_start, flag, TQ_NOALLOC)) 3179 *flag = 0; 3180 } 3181 3182 /* 3183 * Reclaim all unused memory from all caches. Called from the VM system 3184 * when memory gets tight. 3185 */ 3186 void 3187 kmem_reap(void) 3188 { 3189 kmem_reap_common(&kmem_reaping); 3190 } 3191 3192 /* 3193 * Reclaim all unused memory from identifier arenas, called when a vmem 3194 * arena not back by memory is exhausted. Since reaping memory-backed caches 3195 * cannot help with identifier exhaustion, we avoid both a large amount of 3196 * work and unwanted side-effects from reclaim callbacks. 3197 */ 3198 void 3199 kmem_reap_idspace(void) 3200 { 3201 kmem_reap_common(&kmem_reaping_idspace); 3202 } 3203 3204 /* 3205 * Purge all magazines from a cache and set its magazine limit to zero. 3206 * All calls are serialized by the kmem_taskq lock, except for the final 3207 * call from kmem_cache_destroy(). 3208 */ 3209 static void 3210 kmem_cache_magazine_purge(kmem_cache_t *cp) 3211 { 3212 kmem_cpu_cache_t *ccp; 3213 kmem_magazine_t *mp, *pmp; 3214 int rounds, prounds, cpu_seqid; 3215 3216 ASSERT(!list_link_active(&cp->cache_link) || 3217 taskq_member(kmem_taskq, curthread)); 3218 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 3219 3220 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) { 3221 ccp = &cp->cache_cpu[cpu_seqid]; 3222 3223 mutex_enter(&ccp->cc_lock); 3224 mp = ccp->cc_loaded; 3225 pmp = ccp->cc_ploaded; 3226 rounds = ccp->cc_rounds; 3227 prounds = ccp->cc_prounds; 3228 ccp->cc_loaded = NULL; 3229 ccp->cc_ploaded = NULL; 3230 ccp->cc_rounds = -1; 3231 ccp->cc_prounds = -1; 3232 ccp->cc_magsize = 0; 3233 mutex_exit(&ccp->cc_lock); 3234 3235 if (mp) 3236 kmem_magazine_destroy(cp, mp, rounds); 3237 if (pmp) 3238 kmem_magazine_destroy(cp, pmp, prounds); 3239 } 3240 3241 /* 3242 * Updating the working set statistics twice in a row has the 3243 * effect of setting the working set size to zero, so everything 3244 * is eligible for reaping. 3245 */ 3246 kmem_depot_ws_update(cp); 3247 kmem_depot_ws_update(cp); 3248 3249 kmem_depot_ws_reap(cp); 3250 } 3251 3252 /* 3253 * Enable per-cpu magazines on a cache. 3254 */ 3255 static void 3256 kmem_cache_magazine_enable(kmem_cache_t *cp) 3257 { 3258 int cpu_seqid; 3259 3260 if (cp->cache_flags & KMF_NOMAGAZINE) 3261 return; 3262 3263 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) { 3264 kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid]; 3265 mutex_enter(&ccp->cc_lock); 3266 ccp->cc_magsize = cp->cache_magtype->mt_magsize; 3267 mutex_exit(&ccp->cc_lock); 3268 } 3269 3270 } 3271 3272 /* 3273 * Reap (almost) everything right now. See kmem_cache_magazine_purge() 3274 * for explanation of the back-to-back kmem_depot_ws_update() calls. 3275 */ 3276 void 3277 kmem_cache_reap_now(kmem_cache_t *cp) 3278 { 3279 ASSERT(list_link_active(&cp->cache_link)); 3280 3281 kmem_depot_ws_update(cp); 3282 kmem_depot_ws_update(cp); 3283 3284 (void) taskq_dispatch(kmem_taskq, 3285 (task_func_t *)kmem_depot_ws_reap, cp, TQ_SLEEP); 3286 taskq_wait(kmem_taskq); 3287 } 3288 3289 /* 3290 * Recompute a cache's magazine size. The trade-off is that larger magazines 3291 * provide a higher transfer rate with the depot, while smaller magazines 3292 * reduce memory consumption. Magazine resizing is an expensive operation; 3293 * it should not be done frequently. 3294 * 3295 * Changes to the magazine size are serialized by the kmem_taskq lock. 3296 * 3297 * Note: at present this only grows the magazine size. It might be useful 3298 * to allow shrinkage too. 3299 */ 3300 static void 3301 kmem_cache_magazine_resize(kmem_cache_t *cp) 3302 { 3303 kmem_magtype_t *mtp = cp->cache_magtype; 3304 3305 ASSERT(taskq_member(kmem_taskq, curthread)); 3306 3307 if (cp->cache_chunksize < mtp->mt_maxbuf) { 3308 kmem_cache_magazine_purge(cp); 3309 mutex_enter(&cp->cache_depot_lock); 3310 cp->cache_magtype = ++mtp; 3311 cp->cache_depot_contention_prev = 3312 cp->cache_depot_contention + INT_MAX; 3313 mutex_exit(&cp->cache_depot_lock); 3314 kmem_cache_magazine_enable(cp); 3315 } 3316 } 3317 3318 /* 3319 * Rescale a cache's hash table, so that the table size is roughly the 3320 * cache size. We want the average lookup time to be extremely small. 3321 */ 3322 static void 3323 kmem_hash_rescale(kmem_cache_t *cp) 3324 { 3325 kmem_bufctl_t **old_table, **new_table, *bcp; 3326 size_t old_size, new_size, h; 3327 3328 ASSERT(taskq_member(kmem_taskq, curthread)); 3329 3330 new_size = MAX(KMEM_HASH_INITIAL, 3331 1 << (highbit(3 * cp->cache_buftotal + 4) - 2)); 3332 old_size = cp->cache_hash_mask + 1; 3333 3334 if ((old_size >> 1) <= new_size && new_size <= (old_size << 1)) 3335 return; 3336 3337 new_table = vmem_alloc(kmem_hash_arena, new_size * sizeof (void *), 3338 VM_NOSLEEP); 3339 if (new_table == NULL) 3340 return; 3341 bzero(new_table, new_size * sizeof (void *)); 3342 3343 mutex_enter(&cp->cache_lock); 3344 3345 old_size = cp->cache_hash_mask + 1; 3346 old_table = cp->cache_hash_table; 3347 3348 cp->cache_hash_mask = new_size - 1; 3349 cp->cache_hash_table = new_table; 3350 cp->cache_rescale++; 3351 3352 for (h = 0; h < old_size; h++) { 3353 bcp = old_table[h]; 3354 while (bcp != NULL) { 3355 void *addr = bcp->bc_addr; 3356 kmem_bufctl_t *next_bcp = bcp->bc_next; 3357 kmem_bufctl_t **hash_bucket = KMEM_HASH(cp, addr); 3358 bcp->bc_next = *hash_bucket; 3359 *hash_bucket = bcp; 3360 bcp = next_bcp; 3361 } 3362 } 3363 3364 mutex_exit(&cp->cache_lock); 3365 3366 vmem_free(kmem_hash_arena, old_table, old_size * sizeof (void *)); 3367 } 3368 3369 /* 3370 * Perform periodic maintenance on a cache: hash rescaling, depot working-set 3371 * update, magazine resizing, and slab consolidation. 3372 */ 3373 static void 3374 kmem_cache_update(kmem_cache_t *cp) 3375 { 3376 int need_hash_rescale = 0; 3377 int need_magazine_resize = 0; 3378 3379 ASSERT(MUTEX_HELD(&kmem_cache_lock)); 3380 3381 /* 3382 * If the cache has become much larger or smaller than its hash table, 3383 * fire off a request to rescale the hash table. 3384 */ 3385 mutex_enter(&cp->cache_lock); 3386 3387 if ((cp->cache_flags & KMF_HASH) && 3388 (cp->cache_buftotal > (cp->cache_hash_mask << 1) || 3389 (cp->cache_buftotal < (cp->cache_hash_mask >> 1) && 3390 cp->cache_hash_mask > KMEM_HASH_INITIAL))) 3391 need_hash_rescale = 1; 3392 3393 mutex_exit(&cp->cache_lock); 3394 3395 /* 3396 * Update the depot working set statistics. 3397 */ 3398 kmem_depot_ws_update(cp); 3399 3400 /* 3401 * If there's a lot of contention in the depot, 3402 * increase the magazine size. 3403 */ 3404 mutex_enter(&cp->cache_depot_lock); 3405 3406 if (cp->cache_chunksize < cp->cache_magtype->mt_maxbuf && 3407 (int)(cp->cache_depot_contention - 3408 cp->cache_depot_contention_prev) > kmem_depot_contention) 3409 need_magazine_resize = 1; 3410 3411 cp->cache_depot_contention_prev = cp->cache_depot_contention; 3412 3413 mutex_exit(&cp->cache_depot_lock); 3414 3415 if (need_hash_rescale) 3416 (void) taskq_dispatch(kmem_taskq, 3417 (task_func_t *)kmem_hash_rescale, cp, TQ_NOSLEEP); 3418 3419 if (need_magazine_resize) 3420 (void) taskq_dispatch(kmem_taskq, 3421 (task_func_t *)kmem_cache_magazine_resize, cp, TQ_NOSLEEP); 3422 3423 if (cp->cache_defrag != NULL) 3424 (void) taskq_dispatch(kmem_taskq, 3425 (task_func_t *)kmem_cache_scan, cp, TQ_NOSLEEP); 3426 } 3427 3428 static void kmem_update(void *); 3429 3430 static void 3431 kmem_update_timeout(void *dummy) 3432 { 3433 (void) timeout(kmem_update, dummy, kmem_reap_interval); 3434 } 3435 3436 static void 3437 kmem_update(void *dummy) 3438 { 3439 kmem_cache_applyall(kmem_cache_update, NULL, TQ_NOSLEEP); 3440 3441 /* 3442 * We use taskq_dispatch() to reschedule the timeout so that 3443 * kmem_update() becomes self-throttling: it won't schedule 3444 * new tasks until all previous tasks have completed. 3445 */ 3446 if (!taskq_dispatch(kmem_taskq, kmem_update_timeout, dummy, TQ_NOSLEEP)) 3447 kmem_update_timeout(NULL); 3448 } 3449 3450 static int 3451 kmem_cache_kstat_update(kstat_t *ksp, int rw) 3452 { 3453 struct kmem_cache_kstat *kmcp = &kmem_cache_kstat; 3454 kmem_cache_t *cp = ksp->ks_private; 3455 uint64_t cpu_buf_avail; 3456 uint64_t buf_avail = 0; 3457 int cpu_seqid; 3458 long reap; 3459 3460 ASSERT(MUTEX_HELD(&kmem_cache_kstat_lock)); 3461 3462 if (rw == KSTAT_WRITE) 3463 return (EACCES); 3464 3465 mutex_enter(&cp->cache_lock); 3466 3467 kmcp->kmc_alloc_fail.value.ui64 = cp->cache_alloc_fail; 3468 kmcp->kmc_alloc.value.ui64 = cp->cache_slab_alloc; 3469 kmcp->kmc_free.value.ui64 = cp->cache_slab_free; 3470 kmcp->kmc_slab_alloc.value.ui64 = cp->cache_slab_alloc; 3471 kmcp->kmc_slab_free.value.ui64 = cp->cache_slab_free; 3472 3473 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) { 3474 kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid]; 3475 3476 mutex_enter(&ccp->cc_lock); 3477 3478 cpu_buf_avail = 0; 3479 if (ccp->cc_rounds > 0) 3480 cpu_buf_avail += ccp->cc_rounds; 3481 if (ccp->cc_prounds > 0) 3482 cpu_buf_avail += ccp->cc_prounds; 3483 3484 kmcp->kmc_alloc.value.ui64 += ccp->cc_alloc; 3485 kmcp->kmc_free.value.ui64 += ccp->cc_free; 3486 buf_avail += cpu_buf_avail; 3487 3488 mutex_exit(&ccp->cc_lock); 3489 } 3490 3491 mutex_enter(&cp->cache_depot_lock); 3492 3493 kmcp->kmc_depot_alloc.value.ui64 = cp->cache_full.ml_alloc; 3494 kmcp->kmc_depot_free.value.ui64 = cp->cache_empty.ml_alloc; 3495 kmcp->kmc_depot_contention.value.ui64 = cp->cache_depot_contention; 3496 kmcp->kmc_full_magazines.value.ui64 = cp->cache_full.ml_total; 3497 kmcp->kmc_empty_magazines.value.ui64 = cp->cache_empty.ml_total; 3498 kmcp->kmc_magazine_size.value.ui64 = 3499 (cp->cache_flags & KMF_NOMAGAZINE) ? 3500 0 : cp->cache_magtype->mt_magsize; 3501 3502 kmcp->kmc_alloc.value.ui64 += cp->cache_full.ml_alloc; 3503 kmcp->kmc_free.value.ui64 += cp->cache_empty.ml_alloc; 3504 buf_avail += cp->cache_full.ml_total * cp->cache_magtype->mt_magsize; 3505 3506 reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min); 3507 reap = MIN(reap, cp->cache_full.ml_total); 3508 3509 mutex_exit(&cp->cache_depot_lock); 3510 3511 kmcp->kmc_buf_size.value.ui64 = cp->cache_bufsize; 3512 kmcp->kmc_align.value.ui64 = cp->cache_align; 3513 kmcp->kmc_chunk_size.value.ui64 = cp->cache_chunksize; 3514 kmcp->kmc_slab_size.value.ui64 = cp->cache_slabsize; 3515 kmcp->kmc_buf_constructed.value.ui64 = buf_avail; 3516 buf_avail += cp->cache_bufslab; 3517 kmcp->kmc_buf_avail.value.ui64 = buf_avail; 3518 kmcp->kmc_buf_inuse.value.ui64 = cp->cache_buftotal - buf_avail; 3519 kmcp->kmc_buf_total.value.ui64 = cp->cache_buftotal; 3520 kmcp->kmc_buf_max.value.ui64 = cp->cache_bufmax; 3521 kmcp->kmc_slab_create.value.ui64 = cp->cache_slab_create; 3522 kmcp->kmc_slab_destroy.value.ui64 = cp->cache_slab_destroy; 3523 kmcp->kmc_hash_size.value.ui64 = (cp->cache_flags & KMF_HASH) ? 3524 cp->cache_hash_mask + 1 : 0; 3525 kmcp->kmc_hash_lookup_depth.value.ui64 = cp->cache_lookup_depth; 3526 kmcp->kmc_hash_rescale.value.ui64 = cp->cache_rescale; 3527 kmcp->kmc_vmem_source.value.ui64 = cp->cache_arena->vm_id; 3528 kmcp->kmc_reap.value.ui64 = cp->cache_reap; 3529 3530 if (cp->cache_defrag == NULL) { 3531 kmcp->kmc_move_callbacks.value.ui64 = 0; 3532 kmcp->kmc_move_yes.value.ui64 = 0; 3533 kmcp->kmc_move_no.value.ui64 = 0; 3534 kmcp->kmc_move_later.value.ui64 = 0; 3535 kmcp->kmc_move_dont_need.value.ui64 = 0; 3536 kmcp->kmc_move_dont_know.value.ui64 = 0; 3537 kmcp->kmc_move_hunt_found.value.ui64 = 0; 3538 kmcp->kmc_move_slabs_freed.value.ui64 = 0; 3539 kmcp->kmc_defrag.value.ui64 = 0; 3540 kmcp->kmc_scan.value.ui64 = 0; 3541 kmcp->kmc_move_reclaimable.value.ui64 = 0; 3542 } else { 3543 int64_t reclaimable; 3544 3545 kmem_defrag_t *kd = cp->cache_defrag; 3546 kmcp->kmc_move_callbacks.value.ui64 = kd->kmd_callbacks; 3547 kmcp->kmc_move_yes.value.ui64 = kd->kmd_yes; 3548 kmcp->kmc_move_no.value.ui64 = kd->kmd_no; 3549 kmcp->kmc_move_later.value.ui64 = kd->kmd_later; 3550 kmcp->kmc_move_dont_need.value.ui64 = kd->kmd_dont_need; 3551 kmcp->kmc_move_dont_know.value.ui64 = kd->kmd_dont_know; 3552 kmcp->kmc_move_hunt_found.value.ui64 = kd->kmd_hunt_found; 3553 kmcp->kmc_move_slabs_freed.value.ui64 = kd->kmd_slabs_freed; 3554 kmcp->kmc_defrag.value.ui64 = kd->kmd_defrags; 3555 kmcp->kmc_scan.value.ui64 = kd->kmd_scans; 3556 3557 reclaimable = cp->cache_bufslab - (cp->cache_maxchunks - 1); 3558 reclaimable = MAX(reclaimable, 0); 3559 reclaimable += ((uint64_t)reap * cp->cache_magtype->mt_magsize); 3560 kmcp->kmc_move_reclaimable.value.ui64 = reclaimable; 3561 } 3562 3563 mutex_exit(&cp->cache_lock); 3564 return (0); 3565 } 3566 3567 /* 3568 * Return a named statistic about a particular cache. 3569 * This shouldn't be called very often, so it's currently designed for 3570 * simplicity (leverages existing kstat support) rather than efficiency. 3571 */ 3572 uint64_t 3573 kmem_cache_stat(kmem_cache_t *cp, char *name) 3574 { 3575 int i; 3576 kstat_t *ksp = cp->cache_kstat; 3577 kstat_named_t *knp = (kstat_named_t *)&kmem_cache_kstat; 3578 uint64_t value = 0; 3579 3580 if (ksp != NULL) { 3581 mutex_enter(&kmem_cache_kstat_lock); 3582 (void) kmem_cache_kstat_update(ksp, KSTAT_READ); 3583 for (i = 0; i < ksp->ks_ndata; i++) { 3584 if (strcmp(knp[i].name, name) == 0) { 3585 value = knp[i].value.ui64; 3586 break; 3587 } 3588 } 3589 mutex_exit(&kmem_cache_kstat_lock); 3590 } 3591 return (value); 3592 } 3593 3594 /* 3595 * Return an estimate of currently available kernel heap memory. 3596 * On 32-bit systems, physical memory may exceed virtual memory, 3597 * we just truncate the result at 1GB. 3598 */ 3599 size_t 3600 kmem_avail(void) 3601 { 3602 spgcnt_t rmem = availrmem - tune.t_minarmem; 3603 spgcnt_t fmem = freemem - minfree; 3604 3605 return ((size_t)ptob(MIN(MAX(MIN(rmem, fmem), 0), 3606 1 << (30 - PAGESHIFT)))); 3607 } 3608 3609 /* 3610 * Return the maximum amount of memory that is (in theory) allocatable 3611 * from the heap. This may be used as an estimate only since there 3612 * is no guarentee this space will still be available when an allocation 3613 * request is made, nor that the space may be allocated in one big request 3614 * due to kernel heap fragmentation. 3615 */ 3616 size_t 3617 kmem_maxavail(void) 3618 { 3619 spgcnt_t pmem = availrmem - tune.t_minarmem; 3620 spgcnt_t vmem = btop(vmem_size(heap_arena, VMEM_FREE)); 3621 3622 return ((size_t)ptob(MAX(MIN(pmem, vmem), 0))); 3623 } 3624 3625 /* 3626 * Indicate whether memory-intensive kmem debugging is enabled. 3627 */ 3628 int 3629 kmem_debugging(void) 3630 { 3631 return (kmem_flags & (KMF_AUDIT | KMF_REDZONE)); 3632 } 3633 3634 /* binning function, sorts finely at the two extremes */ 3635 #define KMEM_PARTIAL_SLAB_WEIGHT(sp, binshift) \ 3636 ((((sp)->slab_refcnt <= (binshift)) || \ 3637 (((sp)->slab_chunks - (sp)->slab_refcnt) <= (binshift))) \ 3638 ? -(sp)->slab_refcnt \ 3639 : -((binshift) + ((sp)->slab_refcnt >> (binshift)))) 3640 3641 /* 3642 * Minimizing the number of partial slabs on the freelist minimizes 3643 * fragmentation (the ratio of unused buffers held by the slab layer). There are 3644 * two ways to get a slab off of the freelist: 1) free all the buffers on the 3645 * slab, and 2) allocate all the buffers on the slab. It follows that we want 3646 * the most-used slabs at the front of the list where they have the best chance 3647 * of being completely allocated, and the least-used slabs at a safe distance 3648 * from the front to improve the odds that the few remaining buffers will all be 3649 * freed before another allocation can tie up the slab. For that reason a slab 3650 * with a higher slab_refcnt sorts less than than a slab with a lower 3651 * slab_refcnt. 3652 * 3653 * However, if a slab has at least one buffer that is deemed unfreeable, we 3654 * would rather have that slab at the front of the list regardless of 3655 * slab_refcnt, since even one unfreeable buffer makes the entire slab 3656 * unfreeable. If the client returns KMEM_CBRC_NO in response to a cache_move() 3657 * callback, the slab is marked unfreeable for as long as it remains on the 3658 * freelist. 3659 */ 3660 static int 3661 kmem_partial_slab_cmp(const void *p0, const void *p1) 3662 { 3663 const kmem_cache_t *cp; 3664 const kmem_slab_t *s0 = p0; 3665 const kmem_slab_t *s1 = p1; 3666 int w0, w1; 3667 size_t binshift; 3668 3669 ASSERT(KMEM_SLAB_IS_PARTIAL(s0)); 3670 ASSERT(KMEM_SLAB_IS_PARTIAL(s1)); 3671 ASSERT(s0->slab_cache == s1->slab_cache); 3672 cp = s1->slab_cache; 3673 ASSERT(MUTEX_HELD(&cp->cache_lock)); 3674 binshift = cp->cache_partial_binshift; 3675 3676 /* weight of first slab */ 3677 w0 = KMEM_PARTIAL_SLAB_WEIGHT(s0, binshift); 3678 if (s0->slab_flags & KMEM_SLAB_NOMOVE) { 3679 w0 -= cp->cache_maxchunks; 3680 } 3681 3682 /* weight of second slab */ 3683 w1 = KMEM_PARTIAL_SLAB_WEIGHT(s1, binshift); 3684 if (s1->slab_flags & KMEM_SLAB_NOMOVE) { 3685 w1 -= cp->cache_maxchunks; 3686 } 3687 3688 if (w0 < w1) 3689 return (-1); 3690 if (w0 > w1) 3691 return (1); 3692 3693 /* compare pointer values */ 3694 if ((uintptr_t)s0 < (uintptr_t)s1) 3695 return (-1); 3696 if ((uintptr_t)s0 > (uintptr_t)s1) 3697 return (1); 3698 3699 return (0); 3700 } 3701 3702 /* 3703 * It must be valid to call the destructor (if any) on a newly created object. 3704 * That is, the constructor (if any) must leave the object in a valid state for 3705 * the destructor. 3706 */ 3707 kmem_cache_t * 3708 kmem_cache_create( 3709 char *name, /* descriptive name for this cache */ 3710 size_t bufsize, /* size of the objects it manages */ 3711 size_t align, /* required object alignment */ 3712 int (*constructor)(void *, void *, int), /* object constructor */ 3713 void (*destructor)(void *, void *), /* object destructor */ 3714 void (*reclaim)(void *), /* memory reclaim callback */ 3715 void *private, /* pass-thru arg for constr/destr/reclaim */ 3716 vmem_t *vmp, /* vmem source for slab allocation */ 3717 int cflags) /* cache creation flags */ 3718 { 3719 int cpu_seqid; 3720 size_t chunksize; 3721 kmem_cache_t *cp; 3722 kmem_magtype_t *mtp; 3723 size_t csize = KMEM_CACHE_SIZE(max_ncpus); 3724 3725 #ifdef DEBUG 3726 /* 3727 * Cache names should conform to the rules for valid C identifiers 3728 */ 3729 if (!strident_valid(name)) { 3730 cmn_err(CE_CONT, 3731 "kmem_cache_create: '%s' is an invalid cache name\n" 3732 "cache names must conform to the rules for " 3733 "C identifiers\n", name); 3734 } 3735 #endif /* DEBUG */ 3736 3737 if (vmp == NULL) 3738 vmp = kmem_default_arena; 3739 3740 /* 3741 * If this kmem cache has an identifier vmem arena as its source, mark 3742 * it such to allow kmem_reap_idspace(). 3743 */ 3744 ASSERT(!(cflags & KMC_IDENTIFIER)); /* consumer should not set this */ 3745 if (vmp->vm_cflags & VMC_IDENTIFIER) 3746 cflags |= KMC_IDENTIFIER; 3747 3748 /* 3749 * Get a kmem_cache structure. We arrange that cp->cache_cpu[] 3750 * is aligned on a KMEM_CPU_CACHE_SIZE boundary to prevent 3751 * false sharing of per-CPU data. 3752 */ 3753 cp = vmem_xalloc(kmem_cache_arena, csize, KMEM_CPU_CACHE_SIZE, 3754 P2NPHASE(csize, KMEM_CPU_CACHE_SIZE), 0, NULL, NULL, VM_SLEEP); 3755 bzero(cp, csize); 3756 list_link_init(&cp->cache_link); 3757 3758 if (align == 0) 3759 align = KMEM_ALIGN; 3760 3761 /* 3762 * If we're not at least KMEM_ALIGN aligned, we can't use free 3763 * memory to hold bufctl information (because we can't safely 3764 * perform word loads and stores on it). 3765 */ 3766 if (align < KMEM_ALIGN) 3767 cflags |= KMC_NOTOUCH; 3768 3769 if ((align & (align - 1)) != 0 || align > vmp->vm_quantum) 3770 panic("kmem_cache_create: bad alignment %lu", align); 3771 3772 mutex_enter(&kmem_flags_lock); 3773 if (kmem_flags & KMF_RANDOMIZE) 3774 kmem_flags = (((kmem_flags | ~KMF_RANDOM) + 1) & KMF_RANDOM) | 3775 KMF_RANDOMIZE; 3776 cp->cache_flags = (kmem_flags | cflags) & KMF_DEBUG; 3777 mutex_exit(&kmem_flags_lock); 3778 3779 /* 3780 * Make sure all the various flags are reasonable. 3781 */ 3782 ASSERT(!(cflags & KMC_NOHASH) || !(cflags & KMC_NOTOUCH)); 3783 3784 if (cp->cache_flags & KMF_LITE) { 3785 if (bufsize >= kmem_lite_minsize && 3786 align <= kmem_lite_maxalign && 3787 P2PHASE(bufsize, kmem_lite_maxalign) != 0) { 3788 cp->cache_flags |= KMF_BUFTAG; 3789 cp->cache_flags &= ~(KMF_AUDIT | KMF_FIREWALL); 3790 } else { 3791 cp->cache_flags &= ~KMF_DEBUG; 3792 } 3793 } 3794 3795 if (cp->cache_flags & KMF_DEADBEEF) 3796 cp->cache_flags |= KMF_REDZONE; 3797 3798 if ((cflags & KMC_QCACHE) && (cp->cache_flags & KMF_AUDIT)) 3799 cp->cache_flags |= KMF_NOMAGAZINE; 3800 3801 if (cflags & KMC_NODEBUG) 3802 cp->cache_flags &= ~KMF_DEBUG; 3803 3804 if (cflags & KMC_NOTOUCH) 3805 cp->cache_flags &= ~KMF_TOUCH; 3806 3807 if (cflags & KMC_PREFILL) 3808 cp->cache_flags |= KMF_PREFILL; 3809 3810 if (cflags & KMC_NOHASH) 3811 cp->cache_flags &= ~(KMF_AUDIT | KMF_FIREWALL); 3812 3813 if (cflags & KMC_NOMAGAZINE) 3814 cp->cache_flags |= KMF_NOMAGAZINE; 3815 3816 if ((cp->cache_flags & KMF_AUDIT) && !(cflags & KMC_NOTOUCH)) 3817 cp->cache_flags |= KMF_REDZONE; 3818 3819 if (!(cp->cache_flags & KMF_AUDIT)) 3820 cp->cache_flags &= ~KMF_CONTENTS; 3821 3822 if ((cp->cache_flags & KMF_BUFTAG) && bufsize >= kmem_minfirewall && 3823 !(cp->cache_flags & KMF_LITE) && !(cflags & KMC_NOHASH)) 3824 cp->cache_flags |= KMF_FIREWALL; 3825 3826 if (vmp != kmem_default_arena || kmem_firewall_arena == NULL) 3827 cp->cache_flags &= ~KMF_FIREWALL; 3828 3829 if (cp->cache_flags & KMF_FIREWALL) { 3830 cp->cache_flags &= ~KMF_BUFTAG; 3831 cp->cache_flags |= KMF_NOMAGAZINE; 3832 ASSERT(vmp == kmem_default_arena); 3833 vmp = kmem_firewall_arena; 3834 } 3835 3836 /* 3837 * Set cache properties. 3838 */ 3839 (void) strncpy(cp->cache_name, name, KMEM_CACHE_NAMELEN); 3840 strident_canon(cp->cache_name, KMEM_CACHE_NAMELEN + 1); 3841 cp->cache_bufsize = bufsize; 3842 cp->cache_align = align; 3843 cp->cache_constructor = constructor; 3844 cp->cache_destructor = destructor; 3845 cp->cache_reclaim = reclaim; 3846 cp->cache_private = private; 3847 cp->cache_arena = vmp; 3848 cp->cache_cflags = cflags; 3849 3850 /* 3851 * Determine the chunk size. 3852 */ 3853 chunksize = bufsize; 3854 3855 if (align >= KMEM_ALIGN) { 3856 chunksize = P2ROUNDUP(chunksize, KMEM_ALIGN); 3857 cp->cache_bufctl = chunksize - KMEM_ALIGN; 3858 } 3859 3860 if (cp->cache_flags & KMF_BUFTAG) { 3861 cp->cache_bufctl = chunksize; 3862 cp->cache_buftag = chunksize; 3863 if (cp->cache_flags & KMF_LITE) 3864 chunksize += KMEM_BUFTAG_LITE_SIZE(kmem_lite_count); 3865 else 3866 chunksize += sizeof (kmem_buftag_t); 3867 } 3868 3869 if (cp->cache_flags & KMF_DEADBEEF) { 3870 cp->cache_verify = MIN(cp->cache_buftag, kmem_maxverify); 3871 if (cp->cache_flags & KMF_LITE) 3872 cp->cache_verify = sizeof (uint64_t); 3873 } 3874 3875 cp->cache_contents = MIN(cp->cache_bufctl, kmem_content_maxsave); 3876 3877 cp->cache_chunksize = chunksize = P2ROUNDUP(chunksize, align); 3878 3879 /* 3880 * Now that we know the chunk size, determine the optimal slab size. 3881 */ 3882 if (vmp == kmem_firewall_arena) { 3883 cp->cache_slabsize = P2ROUNDUP(chunksize, vmp->vm_quantum); 3884 cp->cache_mincolor = cp->cache_slabsize - chunksize; 3885 cp->cache_maxcolor = cp->cache_mincolor; 3886 cp->cache_flags |= KMF_HASH; 3887 ASSERT(!(cp->cache_flags & KMF_BUFTAG)); 3888 } else if ((cflags & KMC_NOHASH) || (!(cflags & KMC_NOTOUCH) && 3889 !(cp->cache_flags & KMF_AUDIT) && 3890 chunksize < vmp->vm_quantum / KMEM_VOID_FRACTION)) { 3891 cp->cache_slabsize = vmp->vm_quantum; 3892 cp->cache_mincolor = 0; 3893 cp->cache_maxcolor = 3894 (cp->cache_slabsize - sizeof (kmem_slab_t)) % chunksize; 3895 ASSERT(chunksize + sizeof (kmem_slab_t) <= cp->cache_slabsize); 3896 ASSERT(!(cp->cache_flags & KMF_AUDIT)); 3897 } else { 3898 size_t chunks, bestfit, waste, slabsize; 3899 size_t minwaste = LONG_MAX; 3900 3901 for (chunks = 1; chunks <= KMEM_VOID_FRACTION; chunks++) { 3902 slabsize = P2ROUNDUP(chunksize * chunks, 3903 vmp->vm_quantum); 3904 chunks = slabsize / chunksize; 3905 waste = (slabsize % chunksize) / chunks; 3906 if (waste < minwaste) { 3907 minwaste = waste; 3908 bestfit = slabsize; 3909 } 3910 } 3911 if (cflags & KMC_QCACHE) 3912 bestfit = VMEM_QCACHE_SLABSIZE(vmp->vm_qcache_max); 3913 cp->cache_slabsize = bestfit; 3914 cp->cache_mincolor = 0; 3915 cp->cache_maxcolor = bestfit % chunksize; 3916 cp->cache_flags |= KMF_HASH; 3917 } 3918 3919 cp->cache_maxchunks = (cp->cache_slabsize / cp->cache_chunksize); 3920 cp->cache_partial_binshift = highbit(cp->cache_maxchunks / 16) + 1; 3921 3922 /* 3923 * Disallowing prefill when either the DEBUG or HASH flag is set or when 3924 * there is a constructor avoids some tricky issues with debug setup 3925 * that may be revisited later. We cannot allow prefill in a 3926 * metadata cache because of potential recursion. 3927 */ 3928 if (vmp == kmem_msb_arena || 3929 cp->cache_flags & (KMF_HASH | KMF_BUFTAG) || 3930 cp->cache_constructor != NULL) 3931 cp->cache_flags &= ~KMF_PREFILL; 3932 3933 if (cp->cache_flags & KMF_HASH) { 3934 ASSERT(!(cflags & KMC_NOHASH)); 3935 cp->cache_bufctl_cache = (cp->cache_flags & KMF_AUDIT) ? 3936 kmem_bufctl_audit_cache : kmem_bufctl_cache; 3937 } 3938 3939 if (cp->cache_maxcolor >= vmp->vm_quantum) 3940 cp->cache_maxcolor = vmp->vm_quantum - 1; 3941 3942 cp->cache_color = cp->cache_mincolor; 3943 3944 /* 3945 * Initialize the rest of the slab layer. 3946 */ 3947 mutex_init(&cp->cache_lock, NULL, MUTEX_DEFAULT, NULL); 3948 3949 avl_create(&cp->cache_partial_slabs, kmem_partial_slab_cmp, 3950 sizeof (kmem_slab_t), offsetof(kmem_slab_t, slab_link)); 3951 /* LINTED: E_TRUE_LOGICAL_EXPR */ 3952 ASSERT(sizeof (list_node_t) <= sizeof (avl_node_t)); 3953 /* reuse partial slab AVL linkage for complete slab list linkage */ 3954 list_create(&cp->cache_complete_slabs, 3955 sizeof (kmem_slab_t), offsetof(kmem_slab_t, slab_link)); 3956 3957 if (cp->cache_flags & KMF_HASH) { 3958 cp->cache_hash_table = vmem_alloc(kmem_hash_arena, 3959 KMEM_HASH_INITIAL * sizeof (void *), VM_SLEEP); 3960 bzero(cp->cache_hash_table, 3961 KMEM_HASH_INITIAL * sizeof (void *)); 3962 cp->cache_hash_mask = KMEM_HASH_INITIAL - 1; 3963 cp->cache_hash_shift = highbit((ulong_t)chunksize) - 1; 3964 } 3965 3966 /* 3967 * Initialize the depot. 3968 */ 3969 mutex_init(&cp->cache_depot_lock, NULL, MUTEX_DEFAULT, NULL); 3970 3971 for (mtp = kmem_magtype; chunksize <= mtp->mt_minbuf; mtp++) 3972 continue; 3973 3974 cp->cache_magtype = mtp; 3975 3976 /* 3977 * Initialize the CPU layer. 3978 */ 3979 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) { 3980 kmem_cpu_cache_t *ccp = &cp->cache_cpu[cpu_seqid]; 3981 mutex_init(&ccp->cc_lock, NULL, MUTEX_DEFAULT, NULL); 3982 ccp->cc_flags = cp->cache_flags; 3983 ccp->cc_rounds = -1; 3984 ccp->cc_prounds = -1; 3985 } 3986 3987 /* 3988 * Create the cache's kstats. 3989 */ 3990 if ((cp->cache_kstat = kstat_create("unix", 0, cp->cache_name, 3991 "kmem_cache", KSTAT_TYPE_NAMED, 3992 sizeof (kmem_cache_kstat) / sizeof (kstat_named_t), 3993 KSTAT_FLAG_VIRTUAL)) != NULL) { 3994 cp->cache_kstat->ks_data = &kmem_cache_kstat; 3995 cp->cache_kstat->ks_update = kmem_cache_kstat_update; 3996 cp->cache_kstat->ks_private = cp; 3997 cp->cache_kstat->ks_lock = &kmem_cache_kstat_lock; 3998 kstat_install(cp->cache_kstat); 3999 } 4000 4001 /* 4002 * Add the cache to the global list. This makes it visible 4003 * to kmem_update(), so the cache must be ready for business. 4004 */ 4005 mutex_enter(&kmem_cache_lock); 4006 list_insert_tail(&kmem_caches, cp); 4007 mutex_exit(&kmem_cache_lock); 4008 4009 if (kmem_ready) 4010 kmem_cache_magazine_enable(cp); 4011 4012 return (cp); 4013 } 4014 4015 static int 4016 kmem_move_cmp(const void *buf, const void *p) 4017 { 4018 const kmem_move_t *kmm = p; 4019 uintptr_t v1 = (uintptr_t)buf; 4020 uintptr_t v2 = (uintptr_t)kmm->kmm_from_buf; 4021 return (v1 < v2 ? -1 : (v1 > v2 ? 1 : 0)); 4022 } 4023 4024 static void 4025 kmem_reset_reclaim_threshold(kmem_defrag_t *kmd) 4026 { 4027 kmd->kmd_reclaim_numer = 1; 4028 } 4029 4030 /* 4031 * Initially, when choosing candidate slabs for buffers to move, we want to be 4032 * very selective and take only slabs that are less than 4033 * (1 / KMEM_VOID_FRACTION) allocated. If we have difficulty finding candidate 4034 * slabs, then we raise the allocation ceiling incrementally. The reclaim 4035 * threshold is reset to (1 / KMEM_VOID_FRACTION) as soon as the cache is no 4036 * longer fragmented. 4037 */ 4038 static void 4039 kmem_adjust_reclaim_threshold(kmem_defrag_t *kmd, int direction) 4040 { 4041 if (direction > 0) { 4042 /* make it easier to find a candidate slab */ 4043 if (kmd->kmd_reclaim_numer < (KMEM_VOID_FRACTION - 1)) { 4044 kmd->kmd_reclaim_numer++; 4045 } 4046 } else { 4047 /* be more selective */ 4048 if (kmd->kmd_reclaim_numer > 1) { 4049 kmd->kmd_reclaim_numer--; 4050 } 4051 } 4052 } 4053 4054 void 4055 kmem_cache_set_move(kmem_cache_t *cp, 4056 kmem_cbrc_t (*move)(void *, void *, size_t, void *)) 4057 { 4058 kmem_defrag_t *defrag; 4059 4060 ASSERT(move != NULL); 4061 /* 4062 * The consolidator does not support NOTOUCH caches because kmem cannot 4063 * initialize their slabs with the 0xbaddcafe memory pattern, which sets 4064 * a low order bit usable by clients to distinguish uninitialized memory 4065 * from known objects (see kmem_slab_create). 4066 */ 4067 ASSERT(!(cp->cache_cflags & KMC_NOTOUCH)); 4068 ASSERT(!(cp->cache_cflags & KMC_IDENTIFIER)); 4069 4070 /* 4071 * We should not be holding anyone's cache lock when calling 4072 * kmem_cache_alloc(), so allocate in all cases before acquiring the 4073 * lock. 4074 */ 4075 defrag = kmem_cache_alloc(kmem_defrag_cache, KM_SLEEP); 4076 4077 mutex_enter(&cp->cache_lock); 4078 4079 if (KMEM_IS_MOVABLE(cp)) { 4080 if (cp->cache_move == NULL) { 4081 ASSERT(cp->cache_slab_alloc == 0); 4082 4083 cp->cache_defrag = defrag; 4084 defrag = NULL; /* nothing to free */ 4085 bzero(cp->cache_defrag, sizeof (kmem_defrag_t)); 4086 avl_create(&cp->cache_defrag->kmd_moves_pending, 4087 kmem_move_cmp, sizeof (kmem_move_t), 4088 offsetof(kmem_move_t, kmm_entry)); 4089 /* LINTED: E_TRUE_LOGICAL_EXPR */ 4090 ASSERT(sizeof (list_node_t) <= sizeof (avl_node_t)); 4091 /* reuse the slab's AVL linkage for deadlist linkage */ 4092 list_create(&cp->cache_defrag->kmd_deadlist, 4093 sizeof (kmem_slab_t), 4094 offsetof(kmem_slab_t, slab_link)); 4095 kmem_reset_reclaim_threshold(cp->cache_defrag); 4096 } 4097 cp->cache_move = move; 4098 } 4099 4100 mutex_exit(&cp->cache_lock); 4101 4102 if (defrag != NULL) { 4103 kmem_cache_free(kmem_defrag_cache, defrag); /* unused */ 4104 } 4105 } 4106 4107 void 4108 kmem_cache_destroy(kmem_cache_t *cp) 4109 { 4110 int cpu_seqid; 4111 4112 /* 4113 * Remove the cache from the global cache list so that no one else 4114 * can schedule tasks on its behalf, wait for any pending tasks to 4115 * complete, purge the cache, and then destroy it. 4116 */ 4117 mutex_enter(&kmem_cache_lock); 4118 list_remove(&kmem_caches, cp); 4119 mutex_exit(&kmem_cache_lock); 4120 4121 if (kmem_taskq != NULL) 4122 taskq_wait(kmem_taskq); 4123 if (kmem_move_taskq != NULL) 4124 taskq_wait(kmem_move_taskq); 4125 4126 kmem_cache_magazine_purge(cp); 4127 4128 mutex_enter(&cp->cache_lock); 4129 if (cp->cache_buftotal != 0) 4130 cmn_err(CE_WARN, "kmem_cache_destroy: '%s' (%p) not empty", 4131 cp->cache_name, (void *)cp); 4132 if (cp->cache_defrag != NULL) { 4133 avl_destroy(&cp->cache_defrag->kmd_moves_pending); 4134 list_destroy(&cp->cache_defrag->kmd_deadlist); 4135 kmem_cache_free(kmem_defrag_cache, cp->cache_defrag); 4136 cp->cache_defrag = NULL; 4137 } 4138 /* 4139 * The cache is now dead. There should be no further activity. We 4140 * enforce this by setting land mines in the constructor, destructor, 4141 * reclaim, and move routines that induce a kernel text fault if 4142 * invoked. 4143 */ 4144 cp->cache_constructor = (int (*)(void *, void *, int))1; 4145 cp->cache_destructor = (void (*)(void *, void *))2; 4146 cp->cache_reclaim = (void (*)(void *))3; 4147 cp->cache_move = (kmem_cbrc_t (*)(void *, void *, size_t, void *))4; 4148 mutex_exit(&cp->cache_lock); 4149 4150 kstat_delete(cp->cache_kstat); 4151 4152 if (cp->cache_hash_table != NULL) 4153 vmem_free(kmem_hash_arena, cp->cache_hash_table, 4154 (cp->cache_hash_mask + 1) * sizeof (void *)); 4155 4156 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) 4157 mutex_destroy(&cp->cache_cpu[cpu_seqid].cc_lock); 4158 4159 mutex_destroy(&cp->cache_depot_lock); 4160 mutex_destroy(&cp->cache_lock); 4161 4162 vmem_free(kmem_cache_arena, cp, KMEM_CACHE_SIZE(max_ncpus)); 4163 } 4164 4165 /*ARGSUSED*/ 4166 static int 4167 kmem_cpu_setup(cpu_setup_t what, int id, void *arg) 4168 { 4169 ASSERT(MUTEX_HELD(&cpu_lock)); 4170 if (what == CPU_UNCONFIG) { 4171 kmem_cache_applyall(kmem_cache_magazine_purge, 4172 kmem_taskq, TQ_SLEEP); 4173 kmem_cache_applyall(kmem_cache_magazine_enable, 4174 kmem_taskq, TQ_SLEEP); 4175 } 4176 return (0); 4177 } 4178 4179 static void 4180 kmem_alloc_caches_create(const int *array, size_t count, 4181 kmem_cache_t **alloc_table, size_t maxbuf, uint_t shift) 4182 { 4183 char name[KMEM_CACHE_NAMELEN + 1]; 4184 size_t table_unit = (1 << shift); /* range of one alloc_table entry */ 4185 size_t size = table_unit; 4186 int i; 4187 4188 for (i = 0; i < count; i++) { 4189 size_t cache_size = array[i]; 4190 size_t align = KMEM_ALIGN; 4191 kmem_cache_t *cp; 4192 4193 /* if the table has an entry for maxbuf, we're done */ 4194 if (size > maxbuf) 4195 break; 4196 4197 /* cache size must be a multiple of the table unit */ 4198 ASSERT(P2PHASE(cache_size, table_unit) == 0); 4199 4200 /* 4201 * If they allocate a multiple of the coherency granularity, 4202 * they get a coherency-granularity-aligned address. 4203 */ 4204 if (IS_P2ALIGNED(cache_size, 64)) 4205 align = 64; 4206 if (IS_P2ALIGNED(cache_size, PAGESIZE)) 4207 align = PAGESIZE; 4208 (void) snprintf(name, sizeof (name), 4209 "kmem_alloc_%lu", cache_size); 4210 cp = kmem_cache_create(name, cache_size, align, 4211 NULL, NULL, NULL, NULL, NULL, KMC_KMEM_ALLOC); 4212 4213 while (size <= cache_size) { 4214 alloc_table[(size - 1) >> shift] = cp; 4215 size += table_unit; 4216 } 4217 } 4218 4219 ASSERT(size > maxbuf); /* i.e. maxbuf <= max(cache_size) */ 4220 } 4221 4222 static void 4223 kmem_cache_init(int pass, int use_large_pages) 4224 { 4225 int i; 4226 size_t maxbuf; 4227 kmem_magtype_t *mtp; 4228 4229 for (i = 0; i < sizeof (kmem_magtype) / sizeof (*mtp); i++) { 4230 char name[KMEM_CACHE_NAMELEN + 1]; 4231 4232 mtp = &kmem_magtype[i]; 4233 (void) sprintf(name, "kmem_magazine_%d", mtp->mt_magsize); 4234 mtp->mt_cache = kmem_cache_create(name, 4235 (mtp->mt_magsize + 1) * sizeof (void *), 4236 mtp->mt_align, NULL, NULL, NULL, NULL, 4237 kmem_msb_arena, KMC_NOHASH); 4238 } 4239 4240 kmem_slab_cache = kmem_cache_create("kmem_slab_cache", 4241 sizeof (kmem_slab_t), 0, NULL, NULL, NULL, NULL, 4242 kmem_msb_arena, KMC_NOHASH); 4243 4244 kmem_bufctl_cache = kmem_cache_create("kmem_bufctl_cache", 4245 sizeof (kmem_bufctl_t), 0, NULL, NULL, NULL, NULL, 4246 kmem_msb_arena, KMC_NOHASH); 4247 4248 kmem_bufctl_audit_cache = kmem_cache_create("kmem_bufctl_audit_cache", 4249 sizeof (kmem_bufctl_audit_t), 0, NULL, NULL, NULL, NULL, 4250 kmem_msb_arena, KMC_NOHASH); 4251 4252 if (pass == 2) { 4253 kmem_va_arena = vmem_create("kmem_va", 4254 NULL, 0, PAGESIZE, 4255 vmem_alloc, vmem_free, heap_arena, 4256 8 * PAGESIZE, VM_SLEEP); 4257 4258 if (use_large_pages) { 4259 kmem_default_arena = vmem_xcreate("kmem_default", 4260 NULL, 0, PAGESIZE, 4261 segkmem_alloc_lp, segkmem_free_lp, kmem_va_arena, 4262 0, VMC_DUMPSAFE | VM_SLEEP); 4263 } else { 4264 kmem_default_arena = vmem_create("kmem_default", 4265 NULL, 0, PAGESIZE, 4266 segkmem_alloc, segkmem_free, kmem_va_arena, 4267 0, VMC_DUMPSAFE | VM_SLEEP); 4268 } 4269 4270 /* Figure out what our maximum cache size is */ 4271 maxbuf = kmem_max_cached; 4272 if (maxbuf <= KMEM_MAXBUF) { 4273 maxbuf = 0; 4274 kmem_max_cached = KMEM_MAXBUF; 4275 } else { 4276 size_t size = 0; 4277 size_t max = 4278 sizeof (kmem_big_alloc_sizes) / sizeof (int); 4279 /* 4280 * Round maxbuf up to an existing cache size. If maxbuf 4281 * is larger than the largest cache, we truncate it to 4282 * the largest cache's size. 4283 */ 4284 for (i = 0; i < max; i++) { 4285 size = kmem_big_alloc_sizes[i]; 4286 if (maxbuf <= size) 4287 break; 4288 } 4289 kmem_max_cached = maxbuf = size; 4290 } 4291 4292 /* 4293 * The big alloc table may not be completely overwritten, so 4294 * we clear out any stale cache pointers from the first pass. 4295 */ 4296 bzero(kmem_big_alloc_table, sizeof (kmem_big_alloc_table)); 4297 } else { 4298 /* 4299 * During the first pass, the kmem_alloc_* caches 4300 * are treated as metadata. 4301 */ 4302 kmem_default_arena = kmem_msb_arena; 4303 maxbuf = KMEM_BIG_MAXBUF_32BIT; 4304 } 4305 4306 /* 4307 * Set up the default caches to back kmem_alloc() 4308 */ 4309 kmem_alloc_caches_create( 4310 kmem_alloc_sizes, sizeof (kmem_alloc_sizes) / sizeof (int), 4311 kmem_alloc_table, KMEM_MAXBUF, KMEM_ALIGN_SHIFT); 4312 4313 kmem_alloc_caches_create( 4314 kmem_big_alloc_sizes, sizeof (kmem_big_alloc_sizes) / sizeof (int), 4315 kmem_big_alloc_table, maxbuf, KMEM_BIG_SHIFT); 4316 4317 kmem_big_alloc_table_max = maxbuf >> KMEM_BIG_SHIFT; 4318 } 4319 4320 void 4321 kmem_init(void) 4322 { 4323 kmem_cache_t *cp; 4324 int old_kmem_flags = kmem_flags; 4325 int use_large_pages = 0; 4326 size_t maxverify, minfirewall; 4327 4328 kstat_init(); 4329 4330 /* 4331 * Small-memory systems (< 24 MB) can't handle kmem_flags overhead. 4332 */ 4333 if (physmem < btop(24 << 20) && !(old_kmem_flags & KMF_STICKY)) 4334 kmem_flags = 0; 4335 4336 /* 4337 * Don't do firewalled allocations if the heap is less than 1TB 4338 * (i.e. on a 32-bit kernel) 4339 * The resulting VM_NEXTFIT allocations would create too much 4340 * fragmentation in a small heap. 4341 */ 4342 #if defined(_LP64) 4343 maxverify = minfirewall = PAGESIZE / 2; 4344 #else 4345 maxverify = minfirewall = ULONG_MAX; 4346 #endif 4347 4348 /* LINTED */ 4349 ASSERT(sizeof (kmem_cpu_cache_t) == KMEM_CPU_CACHE_SIZE); 4350 4351 list_create(&kmem_caches, sizeof (kmem_cache_t), 4352 offsetof(kmem_cache_t, cache_link)); 4353 4354 kmem_metadata_arena = vmem_create("kmem_metadata", NULL, 0, PAGESIZE, 4355 vmem_alloc, vmem_free, heap_arena, 8 * PAGESIZE, 4356 VM_SLEEP | VMC_NO_QCACHE); 4357 4358 kmem_msb_arena = vmem_create("kmem_msb", NULL, 0, 4359 PAGESIZE, segkmem_alloc, segkmem_free, kmem_metadata_arena, 0, 4360 VMC_DUMPSAFE | VM_SLEEP); 4361 4362 kmem_cache_arena = vmem_create("kmem_cache", NULL, 0, KMEM_ALIGN, 4363 segkmem_alloc, segkmem_free, kmem_metadata_arena, 0, VM_SLEEP); 4364 4365 kmem_hash_arena = vmem_create("kmem_hash", NULL, 0, KMEM_ALIGN, 4366 segkmem_alloc, segkmem_free, kmem_metadata_arena, 0, VM_SLEEP); 4367 4368 kmem_log_arena = vmem_create("kmem_log", NULL, 0, KMEM_ALIGN, 4369 segkmem_alloc, segkmem_free, heap_arena, 0, VM_SLEEP); 4370 4371 kmem_firewall_va_arena = vmem_create("kmem_firewall_va", 4372 NULL, 0, PAGESIZE, 4373 kmem_firewall_va_alloc, kmem_firewall_va_free, heap_arena, 4374 0, VM_SLEEP); 4375 4376 kmem_firewall_arena = vmem_create("kmem_firewall", NULL, 0, PAGESIZE, 4377 segkmem_alloc, segkmem_free, kmem_firewall_va_arena, 0, 4378 VMC_DUMPSAFE | VM_SLEEP); 4379 4380 /* temporary oversize arena for mod_read_system_file */ 4381 kmem_oversize_arena = vmem_create("kmem_oversize", NULL, 0, PAGESIZE, 4382 segkmem_alloc, segkmem_free, heap_arena, 0, VM_SLEEP); 4383 4384 kmem_reap_interval = 15 * hz; 4385 4386 /* 4387 * Read /etc/system. This is a chicken-and-egg problem because 4388 * kmem_flags may be set in /etc/system, but mod_read_system_file() 4389 * needs to use the allocator. The simplest solution is to create 4390 * all the standard kmem caches, read /etc/system, destroy all the 4391 * caches we just created, and then create them all again in light 4392 * of the (possibly) new kmem_flags and other kmem tunables. 4393 */ 4394 kmem_cache_init(1, 0); 4395 4396 mod_read_system_file(boothowto & RB_ASKNAME); 4397 4398 while ((cp = list_tail(&kmem_caches)) != NULL) 4399 kmem_cache_destroy(cp); 4400 4401 vmem_destroy(kmem_oversize_arena); 4402 4403 if (old_kmem_flags & KMF_STICKY) 4404 kmem_flags = old_kmem_flags; 4405 4406 if (!(kmem_flags & KMF_AUDIT)) 4407 vmem_seg_size = offsetof(vmem_seg_t, vs_thread); 4408 4409 if (kmem_maxverify == 0) 4410 kmem_maxverify = maxverify; 4411 4412 if (kmem_minfirewall == 0) 4413 kmem_minfirewall = minfirewall; 4414 4415 /* 4416 * give segkmem a chance to figure out if we are using large pages 4417 * for the kernel heap 4418 */ 4419 use_large_pages = segkmem_lpsetup(); 4420 4421 /* 4422 * To protect against corruption, we keep the actual number of callers 4423 * KMF_LITE records seperate from the tunable. We arbitrarily clamp 4424 * to 16, since the overhead for small buffers quickly gets out of 4425 * hand. 4426 * 4427 * The real limit would depend on the needs of the largest KMC_NOHASH 4428 * cache. 4429 */ 4430 kmem_lite_count = MIN(MAX(0, kmem_lite_pcs), 16); 4431 kmem_lite_pcs = kmem_lite_count; 4432 4433 /* 4434 * Normally, we firewall oversized allocations when possible, but 4435 * if we are using large pages for kernel memory, and we don't have 4436 * any non-LITE debugging flags set, we want to allocate oversized 4437 * buffers from large pages, and so skip the firewalling. 4438 */ 4439 if (use_large_pages && 4440 ((kmem_flags & KMF_LITE) || !(kmem_flags & KMF_DEBUG))) { 4441 kmem_oversize_arena = vmem_xcreate("kmem_oversize", NULL, 0, 4442 PAGESIZE, segkmem_alloc_lp, segkmem_free_lp, heap_arena, 4443 0, VMC_DUMPSAFE | VM_SLEEP); 4444 } else { 4445 kmem_oversize_arena = vmem_create("kmem_oversize", 4446 NULL, 0, PAGESIZE, 4447 segkmem_alloc, segkmem_free, kmem_minfirewall < ULONG_MAX? 4448 kmem_firewall_va_arena : heap_arena, 0, VMC_DUMPSAFE | 4449 VM_SLEEP); 4450 } 4451 4452 kmem_cache_init(2, use_large_pages); 4453 4454 if (kmem_flags & (KMF_AUDIT | KMF_RANDOMIZE)) { 4455 if (kmem_transaction_log_size == 0) 4456 kmem_transaction_log_size = kmem_maxavail() / 50; 4457 kmem_transaction_log = kmem_log_init(kmem_transaction_log_size); 4458 } 4459 4460 if (kmem_flags & (KMF_CONTENTS | KMF_RANDOMIZE)) { 4461 if (kmem_content_log_size == 0) 4462 kmem_content_log_size = kmem_maxavail() / 50; 4463 kmem_content_log = kmem_log_init(kmem_content_log_size); 4464 } 4465 4466 kmem_failure_log = kmem_log_init(kmem_failure_log_size); 4467 4468 kmem_slab_log = kmem_log_init(kmem_slab_log_size); 4469 4470 /* 4471 * Initialize STREAMS message caches so allocb() is available. 4472 * This allows us to initialize the logging framework (cmn_err(9F), 4473 * strlog(9F), etc) so we can start recording messages. 4474 */ 4475 streams_msg_init(); 4476 4477 /* 4478 * Initialize the ZSD framework in Zones so modules loaded henceforth 4479 * can register their callbacks. 4480 */ 4481 zone_zsd_init(); 4482 4483 log_init(); 4484 taskq_init(); 4485 4486 /* 4487 * Warn about invalid or dangerous values of kmem_flags. 4488 * Always warn about unsupported values. 4489 */ 4490 if (((kmem_flags & ~(KMF_AUDIT | KMF_DEADBEEF | KMF_REDZONE | 4491 KMF_CONTENTS | KMF_LITE)) != 0) || 4492 ((kmem_flags & KMF_LITE) && kmem_flags != KMF_LITE)) 4493 cmn_err(CE_WARN, "kmem_flags set to unsupported value 0x%x. " 4494 "See the Solaris Tunable Parameters Reference Manual.", 4495 kmem_flags); 4496 4497 #ifdef DEBUG 4498 if ((kmem_flags & KMF_DEBUG) == 0) 4499 cmn_err(CE_NOTE, "kmem debugging disabled."); 4500 #else 4501 /* 4502 * For non-debug kernels, the only "normal" flags are 0, KMF_LITE, 4503 * KMF_REDZONE, and KMF_CONTENTS (the last because it is only enabled 4504 * if KMF_AUDIT is set). We should warn the user about the performance 4505 * penalty of KMF_AUDIT or KMF_DEADBEEF if they are set and KMF_LITE 4506 * isn't set (since that disables AUDIT). 4507 */ 4508 if (!(kmem_flags & KMF_LITE) && 4509 (kmem_flags & (KMF_AUDIT | KMF_DEADBEEF)) != 0) 4510 cmn_err(CE_WARN, "High-overhead kmem debugging features " 4511 "enabled (kmem_flags = 0x%x). Performance degradation " 4512 "and large memory overhead possible. See the Solaris " 4513 "Tunable Parameters Reference Manual.", kmem_flags); 4514 #endif /* not DEBUG */ 4515 4516 kmem_cache_applyall(kmem_cache_magazine_enable, NULL, TQ_SLEEP); 4517 4518 kmem_ready = 1; 4519 4520 /* 4521 * Initialize the platform-specific aligned/DMA memory allocator. 4522 */ 4523 ka_init(); 4524 4525 /* 4526 * Initialize 32-bit ID cache. 4527 */ 4528 id32_init(); 4529 4530 /* 4531 * Initialize the networking stack so modules loaded can 4532 * register their callbacks. 4533 */ 4534 netstack_init(); 4535 } 4536 4537 static void 4538 kmem_move_init(void) 4539 { 4540 kmem_defrag_cache = kmem_cache_create("kmem_defrag_cache", 4541 sizeof (kmem_defrag_t), 0, NULL, NULL, NULL, NULL, 4542 kmem_msb_arena, KMC_NOHASH); 4543 kmem_move_cache = kmem_cache_create("kmem_move_cache", 4544 sizeof (kmem_move_t), 0, NULL, NULL, NULL, NULL, 4545 kmem_msb_arena, KMC_NOHASH); 4546 4547 /* 4548 * kmem guarantees that move callbacks are sequential and that even 4549 * across multiple caches no two moves ever execute simultaneously. 4550 * Move callbacks are processed on a separate taskq so that client code 4551 * does not interfere with internal maintenance tasks. 4552 */ 4553 kmem_move_taskq = taskq_create_instance("kmem_move_taskq", 0, 1, 4554 minclsyspri, 100, INT_MAX, TASKQ_PREPOPULATE); 4555 } 4556 4557 void 4558 kmem_thread_init(void) 4559 { 4560 kmem_move_init(); 4561 kmem_taskq = taskq_create_instance("kmem_taskq", 0, 1, minclsyspri, 4562 300, INT_MAX, TASKQ_PREPOPULATE); 4563 } 4564 4565 void 4566 kmem_mp_init(void) 4567 { 4568 mutex_enter(&cpu_lock); 4569 register_cpu_setup_func(kmem_cpu_setup, NULL); 4570 mutex_exit(&cpu_lock); 4571 4572 kmem_update_timeout(NULL); 4573 4574 taskq_mp_init(); 4575 } 4576 4577 /* 4578 * Return the slab of the allocated buffer, or NULL if the buffer is not 4579 * allocated. This function may be called with a known slab address to determine 4580 * whether or not the buffer is allocated, or with a NULL slab address to obtain 4581 * an allocated buffer's slab. 4582 */ 4583 static kmem_slab_t * 4584 kmem_slab_allocated(kmem_cache_t *cp, kmem_slab_t *sp, void *buf) 4585 { 4586 kmem_bufctl_t *bcp, *bufbcp; 4587 4588 ASSERT(MUTEX_HELD(&cp->cache_lock)); 4589 ASSERT(sp == NULL || KMEM_SLAB_MEMBER(sp, buf)); 4590 4591 if (cp->cache_flags & KMF_HASH) { 4592 for (bcp = *KMEM_HASH(cp, buf); 4593 (bcp != NULL) && (bcp->bc_addr != buf); 4594 bcp = bcp->bc_next) { 4595 continue; 4596 } 4597 ASSERT(sp != NULL && bcp != NULL ? sp == bcp->bc_slab : 1); 4598 return (bcp == NULL ? NULL : bcp->bc_slab); 4599 } 4600 4601 if (sp == NULL) { 4602 sp = KMEM_SLAB(cp, buf); 4603 } 4604 bufbcp = KMEM_BUFCTL(cp, buf); 4605 for (bcp = sp->slab_head; 4606 (bcp != NULL) && (bcp != bufbcp); 4607 bcp = bcp->bc_next) { 4608 continue; 4609 } 4610 return (bcp == NULL ? sp : NULL); 4611 } 4612 4613 static boolean_t 4614 kmem_slab_is_reclaimable(kmem_cache_t *cp, kmem_slab_t *sp, int flags) 4615 { 4616 long refcnt = sp->slab_refcnt; 4617 4618 ASSERT(cp->cache_defrag != NULL); 4619 4620 /* 4621 * For code coverage we want to be able to move an object within the 4622 * same slab (the only partial slab) even if allocating the destination 4623 * buffer resulted in a completely allocated slab. 4624 */ 4625 if (flags & KMM_DEBUG) { 4626 return ((flags & KMM_DESPERATE) || 4627 ((sp->slab_flags & KMEM_SLAB_NOMOVE) == 0)); 4628 } 4629 4630 /* If we're desperate, we don't care if the client said NO. */ 4631 if (flags & KMM_DESPERATE) { 4632 return (refcnt < sp->slab_chunks); /* any partial */ 4633 } 4634 4635 if (sp->slab_flags & KMEM_SLAB_NOMOVE) { 4636 return (B_FALSE); 4637 } 4638 4639 if ((refcnt == 1) || kmem_move_any_partial) { 4640 return (refcnt < sp->slab_chunks); 4641 } 4642 4643 /* 4644 * The reclaim threshold is adjusted at each kmem_cache_scan() so that 4645 * slabs with a progressively higher percentage of used buffers can be 4646 * reclaimed until the cache as a whole is no longer fragmented. 4647 * 4648 * sp->slab_refcnt kmd_reclaim_numer 4649 * --------------- < ------------------ 4650 * sp->slab_chunks KMEM_VOID_FRACTION 4651 */ 4652 return ((refcnt * KMEM_VOID_FRACTION) < 4653 (sp->slab_chunks * cp->cache_defrag->kmd_reclaim_numer)); 4654 } 4655 4656 static void * 4657 kmem_hunt_mag(kmem_cache_t *cp, kmem_magazine_t *m, int n, void *buf, 4658 void *tbuf) 4659 { 4660 int i; /* magazine round index */ 4661 4662 for (i = 0; i < n; i++) { 4663 if (buf == m->mag_round[i]) { 4664 if (cp->cache_flags & KMF_BUFTAG) { 4665 (void) kmem_cache_free_debug(cp, tbuf, 4666 caller()); 4667 } 4668 m->mag_round[i] = tbuf; 4669 return (buf); 4670 } 4671 } 4672 4673 return (NULL); 4674 } 4675 4676 /* 4677 * Hunt the magazine layer for the given buffer. If found, the buffer is 4678 * removed from the magazine layer and returned, otherwise NULL is returned. 4679 * The state of the returned buffer is freed and constructed. 4680 */ 4681 static void * 4682 kmem_hunt_mags(kmem_cache_t *cp, void *buf) 4683 { 4684 kmem_cpu_cache_t *ccp; 4685 kmem_magazine_t *m; 4686 int cpu_seqid; 4687 int n; /* magazine rounds */ 4688 void *tbuf; /* temporary swap buffer */ 4689 4690 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 4691 4692 /* 4693 * Allocated a buffer to swap with the one we hope to pull out of a 4694 * magazine when found. 4695 */ 4696 tbuf = kmem_cache_alloc(cp, KM_NOSLEEP); 4697 if (tbuf == NULL) { 4698 KMEM_STAT_ADD(kmem_move_stats.kms_hunt_alloc_fail); 4699 return (NULL); 4700 } 4701 if (tbuf == buf) { 4702 KMEM_STAT_ADD(kmem_move_stats.kms_hunt_lucky); 4703 if (cp->cache_flags & KMF_BUFTAG) { 4704 (void) kmem_cache_free_debug(cp, buf, caller()); 4705 } 4706 return (buf); 4707 } 4708 4709 /* Hunt the depot. */ 4710 mutex_enter(&cp->cache_depot_lock); 4711 n = cp->cache_magtype->mt_magsize; 4712 for (m = cp->cache_full.ml_list; m != NULL; m = m->mag_next) { 4713 if (kmem_hunt_mag(cp, m, n, buf, tbuf) != NULL) { 4714 mutex_exit(&cp->cache_depot_lock); 4715 return (buf); 4716 } 4717 } 4718 mutex_exit(&cp->cache_depot_lock); 4719 4720 /* Hunt the per-CPU magazines. */ 4721 for (cpu_seqid = 0; cpu_seqid < max_ncpus; cpu_seqid++) { 4722 ccp = &cp->cache_cpu[cpu_seqid]; 4723 4724 mutex_enter(&ccp->cc_lock); 4725 m = ccp->cc_loaded; 4726 n = ccp->cc_rounds; 4727 if (kmem_hunt_mag(cp, m, n, buf, tbuf) != NULL) { 4728 mutex_exit(&ccp->cc_lock); 4729 return (buf); 4730 } 4731 m = ccp->cc_ploaded; 4732 n = ccp->cc_prounds; 4733 if (kmem_hunt_mag(cp, m, n, buf, tbuf) != NULL) { 4734 mutex_exit(&ccp->cc_lock); 4735 return (buf); 4736 } 4737 mutex_exit(&ccp->cc_lock); 4738 } 4739 4740 kmem_cache_free(cp, tbuf); 4741 return (NULL); 4742 } 4743 4744 /* 4745 * May be called from the kmem_move_taskq, from kmem_cache_move_notify_task(), 4746 * or when the buffer is freed. 4747 */ 4748 static void 4749 kmem_slab_move_yes(kmem_cache_t *cp, kmem_slab_t *sp, void *from_buf) 4750 { 4751 ASSERT(MUTEX_HELD(&cp->cache_lock)); 4752 ASSERT(KMEM_SLAB_MEMBER(sp, from_buf)); 4753 4754 if (!KMEM_SLAB_IS_PARTIAL(sp)) { 4755 return; 4756 } 4757 4758 if (sp->slab_flags & KMEM_SLAB_NOMOVE) { 4759 if (KMEM_SLAB_OFFSET(sp, from_buf) == sp->slab_stuck_offset) { 4760 avl_remove(&cp->cache_partial_slabs, sp); 4761 sp->slab_flags &= ~KMEM_SLAB_NOMOVE; 4762 sp->slab_stuck_offset = (uint32_t)-1; 4763 avl_add(&cp->cache_partial_slabs, sp); 4764 } 4765 } else { 4766 sp->slab_later_count = 0; 4767 sp->slab_stuck_offset = (uint32_t)-1; 4768 } 4769 } 4770 4771 static void 4772 kmem_slab_move_no(kmem_cache_t *cp, kmem_slab_t *sp, void *from_buf) 4773 { 4774 ASSERT(taskq_member(kmem_move_taskq, curthread)); 4775 ASSERT(MUTEX_HELD(&cp->cache_lock)); 4776 ASSERT(KMEM_SLAB_MEMBER(sp, from_buf)); 4777 4778 if (!KMEM_SLAB_IS_PARTIAL(sp)) { 4779 return; 4780 } 4781 4782 avl_remove(&cp->cache_partial_slabs, sp); 4783 sp->slab_later_count = 0; 4784 sp->slab_flags |= KMEM_SLAB_NOMOVE; 4785 sp->slab_stuck_offset = KMEM_SLAB_OFFSET(sp, from_buf); 4786 avl_add(&cp->cache_partial_slabs, sp); 4787 } 4788 4789 static void kmem_move_end(kmem_cache_t *, kmem_move_t *); 4790 4791 /* 4792 * The move callback takes two buffer addresses, the buffer to be moved, and a 4793 * newly allocated and constructed buffer selected by kmem as the destination. 4794 * It also takes the size of the buffer and an optional user argument specified 4795 * at cache creation time. kmem guarantees that the buffer to be moved has not 4796 * been unmapped by the virtual memory subsystem. Beyond that, it cannot 4797 * guarantee the present whereabouts of the buffer to be moved, so it is up to 4798 * the client to safely determine whether or not it is still using the buffer. 4799 * The client must not free either of the buffers passed to the move callback, 4800 * since kmem wants to free them directly to the slab layer. The client response 4801 * tells kmem which of the two buffers to free: 4802 * 4803 * YES kmem frees the old buffer (the move was successful) 4804 * NO kmem frees the new buffer, marks the slab of the old buffer 4805 * non-reclaimable to avoid bothering the client again 4806 * LATER kmem frees the new buffer, increments slab_later_count 4807 * DONT_KNOW kmem frees the new buffer, searches mags for the old buffer 4808 * DONT_NEED kmem frees both the old buffer and the new buffer 4809 * 4810 * The pending callback argument now being processed contains both of the 4811 * buffers (old and new) passed to the move callback function, the slab of the 4812 * old buffer, and flags related to the move request, such as whether or not the 4813 * system was desperate for memory. 4814 * 4815 * Slabs are not freed while there is a pending callback, but instead are kept 4816 * on a deadlist, which is drained after the last callback completes. This means 4817 * that slabs are safe to access until kmem_move_end(), no matter how many of 4818 * their buffers have been freed. Once slab_refcnt reaches zero, it stays at 4819 * zero for as long as the slab remains on the deadlist and until the slab is 4820 * freed. 4821 */ 4822 static void 4823 kmem_move_buffer(kmem_move_t *callback) 4824 { 4825 kmem_cbrc_t response; 4826 kmem_slab_t *sp = callback->kmm_from_slab; 4827 kmem_cache_t *cp = sp->slab_cache; 4828 boolean_t free_on_slab; 4829 4830 ASSERT(taskq_member(kmem_move_taskq, curthread)); 4831 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 4832 ASSERT(KMEM_SLAB_MEMBER(sp, callback->kmm_from_buf)); 4833 4834 /* 4835 * The number of allocated buffers on the slab may have changed since we 4836 * last checked the slab's reclaimability (when the pending move was 4837 * enqueued), or the client may have responded NO when asked to move 4838 * another buffer on the same slab. 4839 */ 4840 if (!kmem_slab_is_reclaimable(cp, sp, callback->kmm_flags)) { 4841 KMEM_STAT_ADD(kmem_move_stats.kms_no_longer_reclaimable); 4842 KMEM_STAT_COND_ADD((callback->kmm_flags & KMM_NOTIFY), 4843 kmem_move_stats.kms_notify_no_longer_reclaimable); 4844 kmem_slab_free(cp, callback->kmm_to_buf); 4845 kmem_move_end(cp, callback); 4846 return; 4847 } 4848 4849 /* 4850 * Hunting magazines is expensive, so we'll wait to do that until the 4851 * client responds KMEM_CBRC_DONT_KNOW. However, checking the slab layer 4852 * is cheap, so we might as well do that here in case we can avoid 4853 * bothering the client. 4854 */ 4855 mutex_enter(&cp->cache_lock); 4856 free_on_slab = (kmem_slab_allocated(cp, sp, 4857 callback->kmm_from_buf) == NULL); 4858 mutex_exit(&cp->cache_lock); 4859 4860 if (free_on_slab) { 4861 KMEM_STAT_ADD(kmem_move_stats.kms_hunt_found_slab); 4862 kmem_slab_free(cp, callback->kmm_to_buf); 4863 kmem_move_end(cp, callback); 4864 return; 4865 } 4866 4867 if (cp->cache_flags & KMF_BUFTAG) { 4868 /* 4869 * Make kmem_cache_alloc_debug() apply the constructor for us. 4870 */ 4871 if (kmem_cache_alloc_debug(cp, callback->kmm_to_buf, 4872 KM_NOSLEEP, 1, caller()) != 0) { 4873 KMEM_STAT_ADD(kmem_move_stats.kms_alloc_fail); 4874 kmem_move_end(cp, callback); 4875 return; 4876 } 4877 } else if (cp->cache_constructor != NULL && 4878 cp->cache_constructor(callback->kmm_to_buf, cp->cache_private, 4879 KM_NOSLEEP) != 0) { 4880 atomic_inc_64(&cp->cache_alloc_fail); 4881 KMEM_STAT_ADD(kmem_move_stats.kms_constructor_fail); 4882 kmem_slab_free(cp, callback->kmm_to_buf); 4883 kmem_move_end(cp, callback); 4884 return; 4885 } 4886 4887 KMEM_STAT_ADD(kmem_move_stats.kms_callbacks); 4888 KMEM_STAT_COND_ADD((callback->kmm_flags & KMM_NOTIFY), 4889 kmem_move_stats.kms_notify_callbacks); 4890 cp->cache_defrag->kmd_callbacks++; 4891 cp->cache_defrag->kmd_thread = curthread; 4892 cp->cache_defrag->kmd_from_buf = callback->kmm_from_buf; 4893 cp->cache_defrag->kmd_to_buf = callback->kmm_to_buf; 4894 DTRACE_PROBE2(kmem__move__start, kmem_cache_t *, cp, kmem_move_t *, 4895 callback); 4896 4897 response = cp->cache_move(callback->kmm_from_buf, 4898 callback->kmm_to_buf, cp->cache_bufsize, cp->cache_private); 4899 4900 DTRACE_PROBE3(kmem__move__end, kmem_cache_t *, cp, kmem_move_t *, 4901 callback, kmem_cbrc_t, response); 4902 cp->cache_defrag->kmd_thread = NULL; 4903 cp->cache_defrag->kmd_from_buf = NULL; 4904 cp->cache_defrag->kmd_to_buf = NULL; 4905 4906 if (response == KMEM_CBRC_YES) { 4907 KMEM_STAT_ADD(kmem_move_stats.kms_yes); 4908 cp->cache_defrag->kmd_yes++; 4909 kmem_slab_free_constructed(cp, callback->kmm_from_buf, B_FALSE); 4910 /* slab safe to access until kmem_move_end() */ 4911 if (sp->slab_refcnt == 0) 4912 cp->cache_defrag->kmd_slabs_freed++; 4913 mutex_enter(&cp->cache_lock); 4914 kmem_slab_move_yes(cp, sp, callback->kmm_from_buf); 4915 mutex_exit(&cp->cache_lock); 4916 kmem_move_end(cp, callback); 4917 return; 4918 } 4919 4920 switch (response) { 4921 case KMEM_CBRC_NO: 4922 KMEM_STAT_ADD(kmem_move_stats.kms_no); 4923 cp->cache_defrag->kmd_no++; 4924 mutex_enter(&cp->cache_lock); 4925 kmem_slab_move_no(cp, sp, callback->kmm_from_buf); 4926 mutex_exit(&cp->cache_lock); 4927 break; 4928 case KMEM_CBRC_LATER: 4929 KMEM_STAT_ADD(kmem_move_stats.kms_later); 4930 cp->cache_defrag->kmd_later++; 4931 mutex_enter(&cp->cache_lock); 4932 if (!KMEM_SLAB_IS_PARTIAL(sp)) { 4933 mutex_exit(&cp->cache_lock); 4934 break; 4935 } 4936 4937 if (++sp->slab_later_count >= KMEM_DISBELIEF) { 4938 KMEM_STAT_ADD(kmem_move_stats.kms_disbelief); 4939 kmem_slab_move_no(cp, sp, callback->kmm_from_buf); 4940 } else if (!(sp->slab_flags & KMEM_SLAB_NOMOVE)) { 4941 sp->slab_stuck_offset = KMEM_SLAB_OFFSET(sp, 4942 callback->kmm_from_buf); 4943 } 4944 mutex_exit(&cp->cache_lock); 4945 break; 4946 case KMEM_CBRC_DONT_NEED: 4947 KMEM_STAT_ADD(kmem_move_stats.kms_dont_need); 4948 cp->cache_defrag->kmd_dont_need++; 4949 kmem_slab_free_constructed(cp, callback->kmm_from_buf, B_FALSE); 4950 if (sp->slab_refcnt == 0) 4951 cp->cache_defrag->kmd_slabs_freed++; 4952 mutex_enter(&cp->cache_lock); 4953 kmem_slab_move_yes(cp, sp, callback->kmm_from_buf); 4954 mutex_exit(&cp->cache_lock); 4955 break; 4956 case KMEM_CBRC_DONT_KNOW: 4957 KMEM_STAT_ADD(kmem_move_stats.kms_dont_know); 4958 cp->cache_defrag->kmd_dont_know++; 4959 if (kmem_hunt_mags(cp, callback->kmm_from_buf) != NULL) { 4960 KMEM_STAT_ADD(kmem_move_stats.kms_hunt_found_mag); 4961 cp->cache_defrag->kmd_hunt_found++; 4962 kmem_slab_free_constructed(cp, callback->kmm_from_buf, 4963 B_TRUE); 4964 if (sp->slab_refcnt == 0) 4965 cp->cache_defrag->kmd_slabs_freed++; 4966 mutex_enter(&cp->cache_lock); 4967 kmem_slab_move_yes(cp, sp, callback->kmm_from_buf); 4968 mutex_exit(&cp->cache_lock); 4969 } 4970 break; 4971 default: 4972 panic("'%s' (%p) unexpected move callback response %d\n", 4973 cp->cache_name, (void *)cp, response); 4974 } 4975 4976 kmem_slab_free_constructed(cp, callback->kmm_to_buf, B_FALSE); 4977 kmem_move_end(cp, callback); 4978 } 4979 4980 /* Return B_FALSE if there is insufficient memory for the move request. */ 4981 static boolean_t 4982 kmem_move_begin(kmem_cache_t *cp, kmem_slab_t *sp, void *buf, int flags) 4983 { 4984 void *to_buf; 4985 avl_index_t index; 4986 kmem_move_t *callback, *pending; 4987 ulong_t n; 4988 4989 ASSERT(taskq_member(kmem_taskq, curthread)); 4990 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 4991 ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING); 4992 4993 callback = kmem_cache_alloc(kmem_move_cache, KM_NOSLEEP); 4994 if (callback == NULL) { 4995 KMEM_STAT_ADD(kmem_move_stats.kms_callback_alloc_fail); 4996 return (B_FALSE); 4997 } 4998 4999 callback->kmm_from_slab = sp; 5000 callback->kmm_from_buf = buf; 5001 callback->kmm_flags = flags; 5002 5003 mutex_enter(&cp->cache_lock); 5004 5005 n = avl_numnodes(&cp->cache_partial_slabs); 5006 if ((n == 0) || ((n == 1) && !(flags & KMM_DEBUG))) { 5007 mutex_exit(&cp->cache_lock); 5008 kmem_cache_free(kmem_move_cache, callback); 5009 return (B_TRUE); /* there is no need for the move request */ 5010 } 5011 5012 pending = avl_find(&cp->cache_defrag->kmd_moves_pending, buf, &index); 5013 if (pending != NULL) { 5014 /* 5015 * If the move is already pending and we're desperate now, 5016 * update the move flags. 5017 */ 5018 if (flags & KMM_DESPERATE) { 5019 pending->kmm_flags |= KMM_DESPERATE; 5020 } 5021 mutex_exit(&cp->cache_lock); 5022 KMEM_STAT_ADD(kmem_move_stats.kms_already_pending); 5023 kmem_cache_free(kmem_move_cache, callback); 5024 return (B_TRUE); 5025 } 5026 5027 to_buf = kmem_slab_alloc_impl(cp, avl_first(&cp->cache_partial_slabs), 5028 B_FALSE); 5029 callback->kmm_to_buf = to_buf; 5030 avl_insert(&cp->cache_defrag->kmd_moves_pending, callback, index); 5031 5032 mutex_exit(&cp->cache_lock); 5033 5034 if (!taskq_dispatch(kmem_move_taskq, (task_func_t *)kmem_move_buffer, 5035 callback, TQ_NOSLEEP)) { 5036 KMEM_STAT_ADD(kmem_move_stats.kms_callback_taskq_fail); 5037 mutex_enter(&cp->cache_lock); 5038 avl_remove(&cp->cache_defrag->kmd_moves_pending, callback); 5039 mutex_exit(&cp->cache_lock); 5040 kmem_slab_free(cp, to_buf); 5041 kmem_cache_free(kmem_move_cache, callback); 5042 return (B_FALSE); 5043 } 5044 5045 return (B_TRUE); 5046 } 5047 5048 static void 5049 kmem_move_end(kmem_cache_t *cp, kmem_move_t *callback) 5050 { 5051 avl_index_t index; 5052 5053 ASSERT(cp->cache_defrag != NULL); 5054 ASSERT(taskq_member(kmem_move_taskq, curthread)); 5055 ASSERT(MUTEX_NOT_HELD(&cp->cache_lock)); 5056 5057 mutex_enter(&cp->cache_lock); 5058 VERIFY(avl_find(&cp->cache_defrag->kmd_moves_pending, 5059 callback->kmm_from_buf, &index) != NULL); 5060 avl_remove(&cp->cache_defrag->kmd_moves_pending, callback); 5061 if (avl_is_empty(&cp->cache_defrag->kmd_moves_pending)) { 5062 list_t *deadlist = &cp->cache_defrag->kmd_deadlist; 5063 kmem_slab_t *sp; 5064 5065 /* 5066 * The last pending move completed. Release all slabs from the 5067 * front of the dead list except for any slab at the tail that 5068 * needs to be released from the context of kmem_move_buffers(). 5069 * kmem deferred unmapping the buffers on these slabs in order 5070 * to guarantee that buffers passed to the move callback have 5071 * been touched only by kmem or by the client itself. 5072 */ 5073 while ((sp = list_remove_head(deadlist)) != NULL) { 5074 if (sp->slab_flags & KMEM_SLAB_MOVE_PENDING) { 5075 list_insert_tail(deadlist, sp); 5076 break; 5077 } 5078 cp->cache_defrag->kmd_deadcount--; 5079 cp->cache_slab_destroy++; 5080 mutex_exit(&cp->cache_lock); 5081 kmem_slab_destroy(cp, sp); 5082 KMEM_STAT_ADD(kmem_move_stats.kms_dead_slabs_freed); 5083 mutex_enter(&cp->cache_lock); 5084 } 5085 } 5086 mutex_exit(&cp->cache_lock); 5087 kmem_cache_free(kmem_move_cache, callback); 5088 } 5089 5090 /* 5091 * Move buffers from least used slabs first by scanning backwards from the end 5092 * of the partial slab list. Scan at most max_scan candidate slabs and move 5093 * buffers from at most max_slabs slabs (0 for all partial slabs in both cases). 5094 * If desperate to reclaim memory, move buffers from any partial slab, otherwise 5095 * skip slabs with a ratio of allocated buffers at or above the current 5096 * threshold. Return the number of unskipped slabs (at most max_slabs, -1 if the 5097 * scan is aborted) so that the caller can adjust the reclaimability threshold 5098 * depending on how many reclaimable slabs it finds. 5099 * 5100 * kmem_move_buffers() drops and reacquires cache_lock every time it issues a 5101 * move request, since it is not valid for kmem_move_begin() to call 5102 * kmem_cache_alloc() or taskq_dispatch() with cache_lock held. 5103 */ 5104 static int 5105 kmem_move_buffers(kmem_cache_t *cp, size_t max_scan, size_t max_slabs, 5106 int flags) 5107 { 5108 kmem_slab_t *sp; 5109 void *buf; 5110 int i, j; /* slab index, buffer index */ 5111 int s; /* reclaimable slabs */ 5112 int b; /* allocated (movable) buffers on reclaimable slab */ 5113 boolean_t success; 5114 int refcnt; 5115 int nomove; 5116 5117 ASSERT(taskq_member(kmem_taskq, curthread)); 5118 ASSERT(MUTEX_HELD(&cp->cache_lock)); 5119 ASSERT(kmem_move_cache != NULL); 5120 ASSERT(cp->cache_move != NULL && cp->cache_defrag != NULL); 5121 ASSERT((flags & KMM_DEBUG) ? !avl_is_empty(&cp->cache_partial_slabs) : 5122 avl_numnodes(&cp->cache_partial_slabs) > 1); 5123 5124 if (kmem_move_blocked) { 5125 return (0); 5126 } 5127 5128 if (kmem_move_fulltilt) { 5129 flags |= KMM_DESPERATE; 5130 } 5131 5132 if (max_scan == 0 || (flags & KMM_DESPERATE)) { 5133 /* 5134 * Scan as many slabs as needed to find the desired number of 5135 * candidate slabs. 5136 */ 5137 max_scan = (size_t)-1; 5138 } 5139 5140 if (max_slabs == 0 || (flags & KMM_DESPERATE)) { 5141 /* Find as many candidate slabs as possible. */ 5142 max_slabs = (size_t)-1; 5143 } 5144 5145 sp = avl_last(&cp->cache_partial_slabs); 5146 ASSERT(KMEM_SLAB_IS_PARTIAL(sp)); 5147 for (i = 0, s = 0; (i < max_scan) && (s < max_slabs) && (sp != NULL) && 5148 ((sp != avl_first(&cp->cache_partial_slabs)) || 5149 (flags & KMM_DEBUG)); 5150 sp = AVL_PREV(&cp->cache_partial_slabs, sp), i++) { 5151 5152 if (!kmem_slab_is_reclaimable(cp, sp, flags)) { 5153 continue; 5154 } 5155 s++; 5156 5157 /* Look for allocated buffers to move. */ 5158 for (j = 0, b = 0, buf = sp->slab_base; 5159 (j < sp->slab_chunks) && (b < sp->slab_refcnt); 5160 buf = (((char *)buf) + cp->cache_chunksize), j++) { 5161 5162 if (kmem_slab_allocated(cp, sp, buf) == NULL) { 5163 continue; 5164 } 5165 5166 b++; 5167 5168 /* 5169 * Prevent the slab from being destroyed while we drop 5170 * cache_lock and while the pending move is not yet 5171 * registered. Flag the pending move while 5172 * kmd_moves_pending may still be empty, since we can't 5173 * yet rely on a non-zero pending move count to prevent 5174 * the slab from being destroyed. 5175 */ 5176 ASSERT(!(sp->slab_flags & KMEM_SLAB_MOVE_PENDING)); 5177 sp->slab_flags |= KMEM_SLAB_MOVE_PENDING; 5178 /* 5179 * Recheck refcnt and nomove after reacquiring the lock, 5180 * since these control the order of partial slabs, and 5181 * we want to know if we can pick up the scan where we 5182 * left off. 5183 */ 5184 refcnt = sp->slab_refcnt; 5185 nomove = (sp->slab_flags & KMEM_SLAB_NOMOVE); 5186 mutex_exit(&cp->cache_lock); 5187 5188 success = kmem_move_begin(cp, sp, buf, flags); 5189 5190 /* 5191 * Now, before the lock is reacquired, kmem could 5192 * process all pending move requests and purge the 5193 * deadlist, so that upon reacquiring the lock, sp has 5194 * been remapped. Or, the client may free all the 5195 * objects on the slab while the pending moves are still 5196 * on the taskq. Therefore, the KMEM_SLAB_MOVE_PENDING 5197 * flag causes the slab to be put at the end of the 5198 * deadlist and prevents it from being destroyed, since 5199 * we plan to destroy it here after reacquiring the 5200 * lock. 5201 */ 5202 mutex_enter(&cp->cache_lock); 5203 ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING); 5204 sp->slab_flags &= ~KMEM_SLAB_MOVE_PENDING; 5205 5206 if (sp->slab_refcnt == 0) { 5207 list_t *deadlist = 5208 &cp->cache_defrag->kmd_deadlist; 5209 list_remove(deadlist, sp); 5210 5211 if (!avl_is_empty( 5212 &cp->cache_defrag->kmd_moves_pending)) { 5213 /* 5214 * A pending move makes it unsafe to 5215 * destroy the slab, because even though 5216 * the move is no longer needed, the 5217 * context where that is determined 5218 * requires the slab to exist. 5219 * Fortunately, a pending move also 5220 * means we don't need to destroy the 5221 * slab here, since it will get 5222 * destroyed along with any other slabs 5223 * on the deadlist after the last 5224 * pending move completes. 5225 */ 5226 list_insert_head(deadlist, sp); 5227 KMEM_STAT_ADD(kmem_move_stats. 5228 kms_endscan_slab_dead); 5229 return (-1); 5230 } 5231 5232 /* 5233 * Destroy the slab now if it was completely 5234 * freed while we dropped cache_lock and there 5235 * are no pending moves. Since slab_refcnt 5236 * cannot change once it reaches zero, no new 5237 * pending moves from that slab are possible. 5238 */ 5239 cp->cache_defrag->kmd_deadcount--; 5240 cp->cache_slab_destroy++; 5241 mutex_exit(&cp->cache_lock); 5242 kmem_slab_destroy(cp, sp); 5243 KMEM_STAT_ADD(kmem_move_stats. 5244 kms_dead_slabs_freed); 5245 KMEM_STAT_ADD(kmem_move_stats. 5246 kms_endscan_slab_destroyed); 5247 mutex_enter(&cp->cache_lock); 5248 /* 5249 * Since we can't pick up the scan where we left 5250 * off, abort the scan and say nothing about the 5251 * number of reclaimable slabs. 5252 */ 5253 return (-1); 5254 } 5255 5256 if (!success) { 5257 /* 5258 * Abort the scan if there is not enough memory 5259 * for the request and say nothing about the 5260 * number of reclaimable slabs. 5261 */ 5262 KMEM_STAT_COND_ADD(s < max_slabs, 5263 kmem_move_stats.kms_endscan_nomem); 5264 return (-1); 5265 } 5266 5267 /* 5268 * The slab's position changed while the lock was 5269 * dropped, so we don't know where we are in the 5270 * sequence any more. 5271 */ 5272 if (sp->slab_refcnt != refcnt) { 5273 /* 5274 * If this is a KMM_DEBUG move, the slab_refcnt 5275 * may have changed because we allocated a 5276 * destination buffer on the same slab. In that 5277 * case, we're not interested in counting it. 5278 */ 5279 KMEM_STAT_COND_ADD(!(flags & KMM_DEBUG) && 5280 (s < max_slabs), 5281 kmem_move_stats.kms_endscan_refcnt_changed); 5282 return (-1); 5283 } 5284 if ((sp->slab_flags & KMEM_SLAB_NOMOVE) != nomove) { 5285 KMEM_STAT_COND_ADD(s < max_slabs, 5286 kmem_move_stats.kms_endscan_nomove_changed); 5287 return (-1); 5288 } 5289 5290 /* 5291 * Generating a move request allocates a destination 5292 * buffer from the slab layer, bumping the first partial 5293 * slab if it is completely allocated. If the current 5294 * slab becomes the first partial slab as a result, we 5295 * can't continue to scan backwards. 5296 * 5297 * If this is a KMM_DEBUG move and we allocated the 5298 * destination buffer from the last partial slab, then 5299 * the buffer we're moving is on the same slab and our 5300 * slab_refcnt has changed, causing us to return before 5301 * reaching here if there are no partial slabs left. 5302 */ 5303 ASSERT(!avl_is_empty(&cp->cache_partial_slabs)); 5304 if (sp == avl_first(&cp->cache_partial_slabs)) { 5305 /* 5306 * We're not interested in a second KMM_DEBUG 5307 * move. 5308 */ 5309 goto end_scan; 5310 } 5311 } 5312 } 5313 end_scan: 5314 5315 KMEM_STAT_COND_ADD(!(flags & KMM_DEBUG) && 5316 (s < max_slabs) && 5317 (sp == avl_first(&cp->cache_partial_slabs)), 5318 kmem_move_stats.kms_endscan_freelist); 5319 5320 return (s); 5321 } 5322 5323 typedef struct kmem_move_notify_args { 5324 kmem_cache_t *kmna_cache; 5325 void *kmna_buf; 5326 } kmem_move_notify_args_t; 5327 5328 static void 5329 kmem_cache_move_notify_task(void *arg) 5330 { 5331 kmem_move_notify_args_t *args = arg; 5332 kmem_cache_t *cp = args->kmna_cache; 5333 void *buf = args->kmna_buf; 5334 kmem_slab_t *sp; 5335 5336 ASSERT(taskq_member(kmem_taskq, curthread)); 5337 ASSERT(list_link_active(&cp->cache_link)); 5338 5339 kmem_free(args, sizeof (kmem_move_notify_args_t)); 5340 mutex_enter(&cp->cache_lock); 5341 sp = kmem_slab_allocated(cp, NULL, buf); 5342 5343 /* Ignore the notification if the buffer is no longer allocated. */ 5344 if (sp == NULL) { 5345 mutex_exit(&cp->cache_lock); 5346 return; 5347 } 5348 5349 /* Ignore the notification if there's no reason to move the buffer. */ 5350 if (avl_numnodes(&cp->cache_partial_slabs) > 1) { 5351 /* 5352 * So far the notification is not ignored. Ignore the 5353 * notification if the slab is not marked by an earlier refusal 5354 * to move a buffer. 5355 */ 5356 if (!(sp->slab_flags & KMEM_SLAB_NOMOVE) && 5357 (sp->slab_later_count == 0)) { 5358 mutex_exit(&cp->cache_lock); 5359 return; 5360 } 5361 5362 kmem_slab_move_yes(cp, sp, buf); 5363 ASSERT(!(sp->slab_flags & KMEM_SLAB_MOVE_PENDING)); 5364 sp->slab_flags |= KMEM_SLAB_MOVE_PENDING; 5365 mutex_exit(&cp->cache_lock); 5366 /* see kmem_move_buffers() about dropping the lock */ 5367 (void) kmem_move_begin(cp, sp, buf, KMM_NOTIFY); 5368 mutex_enter(&cp->cache_lock); 5369 ASSERT(sp->slab_flags & KMEM_SLAB_MOVE_PENDING); 5370 sp->slab_flags &= ~KMEM_SLAB_MOVE_PENDING; 5371 if (sp->slab_refcnt == 0) { 5372 list_t *deadlist = &cp->cache_defrag->kmd_deadlist; 5373 list_remove(deadlist, sp); 5374 5375 if (!avl_is_empty( 5376 &cp->cache_defrag->kmd_moves_pending)) { 5377 list_insert_head(deadlist, sp); 5378 mutex_exit(&cp->cache_lock); 5379 KMEM_STAT_ADD(kmem_move_stats. 5380 kms_notify_slab_dead); 5381 return; 5382 } 5383 5384 cp->cache_defrag->kmd_deadcount--; 5385 cp->cache_slab_destroy++; 5386 mutex_exit(&cp->cache_lock); 5387 kmem_slab_destroy(cp, sp); 5388 KMEM_STAT_ADD(kmem_move_stats.kms_dead_slabs_freed); 5389 KMEM_STAT_ADD(kmem_move_stats. 5390 kms_notify_slab_destroyed); 5391 return; 5392 } 5393 } else { 5394 kmem_slab_move_yes(cp, sp, buf); 5395 } 5396 mutex_exit(&cp->cache_lock); 5397 } 5398 5399 void 5400 kmem_cache_move_notify(kmem_cache_t *cp, void *buf) 5401 { 5402 kmem_move_notify_args_t *args; 5403 5404 KMEM_STAT_ADD(kmem_move_stats.kms_notify); 5405 args = kmem_alloc(sizeof (kmem_move_notify_args_t), KM_NOSLEEP); 5406 if (args != NULL) { 5407 args->kmna_cache = cp; 5408 args->kmna_buf = buf; 5409 if (!taskq_dispatch(kmem_taskq, 5410 (task_func_t *)kmem_cache_move_notify_task, args, 5411 TQ_NOSLEEP)) 5412 kmem_free(args, sizeof (kmem_move_notify_args_t)); 5413 } 5414 } 5415 5416 static void 5417 kmem_cache_defrag(kmem_cache_t *cp) 5418 { 5419 size_t n; 5420 5421 ASSERT(cp->cache_defrag != NULL); 5422 5423 mutex_enter(&cp->cache_lock); 5424 n = avl_numnodes(&cp->cache_partial_slabs); 5425 if (n > 1) { 5426 /* kmem_move_buffers() drops and reacquires cache_lock */ 5427 KMEM_STAT_ADD(kmem_move_stats.kms_defrags); 5428 cp->cache_defrag->kmd_defrags++; 5429 (void) kmem_move_buffers(cp, n, 0, KMM_DESPERATE); 5430 } 5431 mutex_exit(&cp->cache_lock); 5432 } 5433 5434 /* Is this cache above the fragmentation threshold? */ 5435 static boolean_t 5436 kmem_cache_frag_threshold(kmem_cache_t *cp, uint64_t nfree) 5437 { 5438 /* 5439 * nfree kmem_frag_numer 5440 * ------------------ > --------------- 5441 * cp->cache_buftotal kmem_frag_denom 5442 */ 5443 return ((nfree * kmem_frag_denom) > 5444 (cp->cache_buftotal * kmem_frag_numer)); 5445 } 5446 5447 static boolean_t 5448 kmem_cache_is_fragmented(kmem_cache_t *cp, boolean_t *doreap) 5449 { 5450 boolean_t fragmented; 5451 uint64_t nfree; 5452 5453 ASSERT(MUTEX_HELD(&cp->cache_lock)); 5454 *doreap = B_FALSE; 5455 5456 if (kmem_move_fulltilt) { 5457 if (avl_numnodes(&cp->cache_partial_slabs) > 1) { 5458 return (B_TRUE); 5459 } 5460 } else { 5461 if ((cp->cache_complete_slab_count + avl_numnodes( 5462 &cp->cache_partial_slabs)) < kmem_frag_minslabs) { 5463 return (B_FALSE); 5464 } 5465 } 5466 5467 nfree = cp->cache_bufslab; 5468 fragmented = ((avl_numnodes(&cp->cache_partial_slabs) > 1) && 5469 kmem_cache_frag_threshold(cp, nfree)); 5470 5471 /* 5472 * Free buffers in the magazine layer appear allocated from the point of 5473 * view of the slab layer. We want to know if the slab layer would 5474 * appear fragmented if we included free buffers from magazines that 5475 * have fallen out of the working set. 5476 */ 5477 if (!fragmented) { 5478 long reap; 5479 5480 mutex_enter(&cp->cache_depot_lock); 5481 reap = MIN(cp->cache_full.ml_reaplimit, cp->cache_full.ml_min); 5482 reap = MIN(reap, cp->cache_full.ml_total); 5483 mutex_exit(&cp->cache_depot_lock); 5484 5485 nfree += ((uint64_t)reap * cp->cache_magtype->mt_magsize); 5486 if (kmem_cache_frag_threshold(cp, nfree)) { 5487 *doreap = B_TRUE; 5488 } 5489 } 5490 5491 return (fragmented); 5492 } 5493 5494 /* Called periodically from kmem_taskq */ 5495 static void 5496 kmem_cache_scan(kmem_cache_t *cp) 5497 { 5498 boolean_t reap = B_FALSE; 5499 kmem_defrag_t *kmd; 5500 5501 ASSERT(taskq_member(kmem_taskq, curthread)); 5502 5503 mutex_enter(&cp->cache_lock); 5504 5505 kmd = cp->cache_defrag; 5506 if (kmd->kmd_consolidate > 0) { 5507 kmd->kmd_consolidate--; 5508 mutex_exit(&cp->cache_lock); 5509 kmem_cache_reap(cp); 5510 return; 5511 } 5512 5513 if (kmem_cache_is_fragmented(cp, &reap)) { 5514 size_t slabs_found; 5515 5516 /* 5517 * Consolidate reclaimable slabs from the end of the partial 5518 * slab list (scan at most kmem_reclaim_scan_range slabs to find 5519 * reclaimable slabs). Keep track of how many candidate slabs we 5520 * looked for and how many we actually found so we can adjust 5521 * the definition of a candidate slab if we're having trouble 5522 * finding them. 5523 * 5524 * kmem_move_buffers() drops and reacquires cache_lock. 5525 */ 5526 KMEM_STAT_ADD(kmem_move_stats.kms_scans); 5527 kmd->kmd_scans++; 5528 slabs_found = kmem_move_buffers(cp, kmem_reclaim_scan_range, 5529 kmem_reclaim_max_slabs, 0); 5530 if (slabs_found >= 0) { 5531 kmd->kmd_slabs_sought += kmem_reclaim_max_slabs; 5532 kmd->kmd_slabs_found += slabs_found; 5533 } 5534 5535 if (++kmd->kmd_tries >= kmem_reclaim_scan_range) { 5536 kmd->kmd_tries = 0; 5537 5538 /* 5539 * If we had difficulty finding candidate slabs in 5540 * previous scans, adjust the threshold so that 5541 * candidates are easier to find. 5542 */ 5543 if (kmd->kmd_slabs_found == kmd->kmd_slabs_sought) { 5544 kmem_adjust_reclaim_threshold(kmd, -1); 5545 } else if ((kmd->kmd_slabs_found * 2) < 5546 kmd->kmd_slabs_sought) { 5547 kmem_adjust_reclaim_threshold(kmd, 1); 5548 } 5549 kmd->kmd_slabs_sought = 0; 5550 kmd->kmd_slabs_found = 0; 5551 } 5552 } else { 5553 kmem_reset_reclaim_threshold(cp->cache_defrag); 5554 #ifdef DEBUG 5555 if (!avl_is_empty(&cp->cache_partial_slabs)) { 5556 /* 5557 * In a debug kernel we want the consolidator to 5558 * run occasionally even when there is plenty of 5559 * memory. 5560 */ 5561 uint16_t debug_rand; 5562 5563 (void) random_get_bytes((uint8_t *)&debug_rand, 2); 5564 if (!kmem_move_noreap && 5565 ((debug_rand % kmem_mtb_reap) == 0)) { 5566 mutex_exit(&cp->cache_lock); 5567 KMEM_STAT_ADD(kmem_move_stats.kms_debug_reaps); 5568 kmem_cache_reap(cp); 5569 return; 5570 } else if ((debug_rand % kmem_mtb_move) == 0) { 5571 KMEM_STAT_ADD(kmem_move_stats.kms_scans); 5572 KMEM_STAT_ADD(kmem_move_stats.kms_debug_scans); 5573 kmd->kmd_scans++; 5574 (void) kmem_move_buffers(cp, 5575 kmem_reclaim_scan_range, 1, KMM_DEBUG); 5576 } 5577 } 5578 #endif /* DEBUG */ 5579 } 5580 5581 mutex_exit(&cp->cache_lock); 5582 5583 if (reap) { 5584 KMEM_STAT_ADD(kmem_move_stats.kms_scan_depot_ws_reaps); 5585 kmem_depot_ws_reap(cp); 5586 } 5587 }