1 /*- 2 * Copyright (c) 2002-2005, 2009 Jeffrey Roberson <jeff@FreeBSD.org> 3 * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice unmodified, this list of conditions, and the following 11 * disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 * 29 */ 30 31 /* 32 * This file includes definitions, structures, prototypes, and inlines that 33 * should not be used outside of the actual implementation of UMA. 34 */ 35 36 /* 37 * Here's a quick description of the relationship between the objects: 38 * 39 * Kegs contain lists of slabs which are stored in either the full bin, empty 40 * bin, or partially allocated bin, to reduce fragmentation. They also contain 41 * the user supplied value for size, which is adjusted for alignment purposes 42 * and rsize is the result of that. The Keg also stores information for 43 * managing a hash of page addresses that maps pages to uma_slab_t structures 44 * for pages that don't have embedded uma_slab_t's. 45 * 46 * The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may 47 * be allocated off the page from a special slab zone. The free list within a 48 * slab is managed with a linked list of indices, which are 8 bit values. If 49 * UMA_SLAB_SIZE is defined to be too large I will have to switch to 16bit 50 * values. Currently on alpha you can get 250 or so 32 byte items and on x86 51 * you can get 250 or so 16byte items. For item sizes that would yield more 52 * than 10% memory waste we potentially allocate a separate uma_slab_t if this 53 * will improve the number of items per slab that will fit. 54 * 55 * Other potential space optimizations are storing the 8bit of linkage in space 56 * wasted between items due to alignment problems. This may yield a much better 57 * memory footprint for certain sizes of objects. Another alternative is to 58 * increase the UMA_SLAB_SIZE, or allow for dynamic slab sizes. I prefer 59 * dynamic slab sizes because we could stick with 8 bit indices and only use 60 * large slab sizes for zones with a lot of waste per slab. This may create 61 * inefficiencies in the vm subsystem due to fragmentation in the address space. 62 * 63 * The only really gross cases, with regards to memory waste, are for those 64 * items that are just over half the page size. You can get nearly 50% waste, 65 * so you fall back to the memory footprint of the power of two allocator. I 66 * have looked at memory allocation sizes on many of the machines available to 67 * me, and there does not seem to be an abundance of allocations at this range 68 * so at this time it may not make sense to optimize for it. This can, of 69 * course, be solved with dynamic slab sizes. 70 * 71 * Kegs may serve multiple Zones but by far most of the time they only serve 72 * one. When a Zone is created, a Keg is allocated and setup for it. While 73 * the backing Keg stores slabs, the Zone caches Buckets of items allocated 74 * from the slabs. Each Zone is equipped with an init/fini and ctor/dtor 75 * pair, as well as with its own set of small per-CPU caches, layered above 76 * the Zone's general Bucket cache. 77 * 78 * The PCPU caches are protected by critical sections, and may be accessed 79 * safely only from their associated CPU, while the Zones backed by the same 80 * Keg all share a common Keg lock (to coalesce contention on the backing 81 * slabs). The backing Keg typically only serves one Zone but in the case of 82 * multiple Zones, one of the Zones is considered the Master Zone and all 83 * Zone-related stats from the Keg are done in the Master Zone. For an 84 * example of a Multi-Zone setup, refer to the Mbuf allocation code. 85 */ 86 87 /* 88 * This is the representation for normal (Non OFFPAGE slab) 89 * 90 * i == item 91 * s == slab pointer 92 * 93 * <---------------- Page (UMA_SLAB_SIZE) ------------------> 94 * ___________________________________________________________ 95 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ | 96 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header|| 97 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| 98 * |___________________________________________________________| 99 * 100 * 101 * This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE. 102 * 103 * ___________________________________________________________ 104 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ | 105 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| | 106 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| | 107 * |___________________________________________________________| 108 * ___________ ^ 109 * |slab header| | 110 * |___________|---* 111 * 112 */ 113 114 #ifndef VM_UMA_INT_H 115 #define VM_UMA_INT_H 116 117 #define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */ 118 #define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */ 119 #define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */ 120 121 #define UMA_BOOT_PAGES 64 /* Pages allocated for startup */ 122 123 /* Max waste percentage before going to off page slab management */ 124 #define UMA_MAX_WASTE 10 125 126 /* 127 * I doubt there will be many cases where this is exceeded. This is the initial 128 * size of the hash table for uma_slabs that are managed off page. This hash 129 * does expand by powers of two. Currently it doesn't get smaller. 130 */ 131 #define UMA_HASH_SIZE_INIT 32 132 133 /* 134 * I should investigate other hashing algorithms. This should yield a low 135 * number of collisions if the pages are relatively contiguous. 136 * 137 * This is the same algorithm that most processor caches use. 138 * 139 * I'm shifting and masking instead of % because it should be faster. 140 */ 141 142 #define UMA_HASH(h, s) ((((unsigned long)s) >> UMA_SLAB_SHIFT) & \ 143 (h)->uh_hashmask) 144 145 #define UMA_HASH_INSERT(h, s, mem) \ 146 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ 147 (mem))], (s), us_hlink) 148 #define UMA_HASH_REMOVE(h, s, mem) \ 149 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ 150 (mem))], (s), uma_slab, us_hlink) 151 152 /* Hash table for freed address -> slab translation */ 153 154 SLIST_HEAD(slabhead, uma_slab); 155 156 struct uma_hash { 157 struct slabhead *uh_slab_hash; /* Hash table for slabs */ 158 int uh_hashsize; /* Current size of the hash table */ 159 int uh_hashmask; /* Mask used during hashing */ 160 }; 161 162 /* 163 * align field or structure to cache line 164 */ 165 #if defined(__amd64__) 166 #define UMA_ALIGN __aligned(CACHE_LINE_SIZE) 167 #else 168 #define UMA_ALIGN 169 #endif 170 171 /* 172 * Structures for per cpu queues. 173 */ 174 175 struct uma_bucket { 176 LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ 177 int16_t ub_cnt; /* Count of free items. */ 178 int16_t ub_entries; /* Max items. */ 179 void *ub_bucket[]; /* actual allocation storage */ 180 }; 181 182 typedef struct uma_bucket * uma_bucket_t; 183 184 struct uma_cache { 185 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 186 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 187 uint64_t uc_allocs; /* Count of allocations */ 188 uint64_t uc_frees; /* Count of frees */ 189 } UMA_ALIGN; 190 191 typedef struct uma_cache * uma_cache_t; 192 193 /* 194 * Keg management structure 195 * 196 * TODO: Optimize for cache line size 197 * 198 */ 199 struct uma_keg { 200 struct mtx uk_lock; /* Lock for the keg */ 201 struct uma_hash uk_hash; 202 203 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 204 LIST_HEAD(,uma_slab) uk_part_slab; /* partially allocated slabs */ 205 LIST_HEAD(,uma_slab) uk_free_slab; /* empty slab list */ 206 LIST_HEAD(,uma_slab) uk_full_slab; /* full slabs */ 207 208 uint32_t uk_recurse; /* Allocation recursion count */ 209 uint32_t uk_align; /* Alignment mask */ 210 uint32_t uk_pages; /* Total page count */ 211 uint32_t uk_free; /* Count of items free in slabs */ 212 uint32_t uk_size; /* Requested size of each item */ 213 uint32_t uk_rsize; /* Real size of each item */ 214 uint32_t uk_maxpages; /* Maximum number of pages to alloc */ 215 216 uma_init uk_init; /* Keg's init routine */ 217 uma_fini uk_fini; /* Keg's fini routine */ 218 uma_alloc uk_allocf; /* Allocation function */ 219 uma_free uk_freef; /* Free routine */ 220 221 u_long uk_offset; /* Next free offset from base KVA */ 222 vm_offset_t uk_kva; /* Zone base KVA */ 223 uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ 224 225 uint16_t uk_slabsize; /* Slab size for this keg */ 226 uint16_t uk_pgoff; /* Offset to uma_slab struct */ 227 uint16_t uk_ppera; /* pages per allocation from backend */ 228 uint16_t uk_ipers; /* Items per slab */ 229 uint32_t uk_flags; /* Internal flags */ 230 231 /* Least used fields go to the last cache line. */ 232 const char *uk_name; /* Name of creating zone. */ 233 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 234 }; 235 typedef struct uma_keg * uma_keg_t; 236 237 /* Page management structure */ 238 239 /* Sorry for the union, but space efficiency is important */ 240 struct uma_slab_head { 241 uma_keg_t us_keg; /* Keg we live in */ 242 union { 243 LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ 244 unsigned long _us_size; /* Size of allocation */ 245 } us_type; 246 SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ 247 uint8_t *us_data; /* First item */ 248 uint16_t us_freecount; /* How many are free? */ 249 uint8_t us_flags; /* Page flags see uma.h */ 250 uint8_t us_firstfree; /* First free item index */ 251 }; 252 253 /* The standard slab structure */ 254 struct uma_slab { 255 struct uma_slab_head us_head; /* slab header data */ 256 struct { 257 uint8_t us_item; 258 } us_freelist[1]; /* actual number bigger */ 259 }; 260 261 /* 262 * The slab structure for UMA_ZONE_REFCNT zones for whose items we 263 * maintain reference counters in the slab for. 264 */ 265 struct uma_slab_refcnt { 266 struct uma_slab_head us_head; /* slab header data */ 267 struct { 268 uint8_t us_item; 269 uint32_t us_refcnt; 270 } us_freelist[1]; /* actual number bigger */ 271 }; 272 273 #define us_keg us_head.us_keg 274 #define us_link us_head.us_type._us_link 275 #define us_size us_head.us_type._us_size 276 #define us_hlink us_head.us_hlink 277 #define us_data us_head.us_data 278 #define us_flags us_head.us_flags 279 #define us_freecount us_head.us_freecount 280 #define us_firstfree us_head.us_firstfree 281 282 typedef struct uma_slab * uma_slab_t; 283 typedef struct uma_slab_refcnt * uma_slabrefcnt_t; 284 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int); 285 286 287 /* 288 * These give us the size of one free item reference within our corresponding 289 * uma_slab structures, so that our calculations during zone setup are correct 290 * regardless of what the compiler decides to do with padding the structure 291 * arrays within uma_slab. 292 */ 293 #define UMA_FRITM_SZ (sizeof(struct uma_slab) - sizeof(struct uma_slab_head)) 294 #define UMA_FRITMREF_SZ (sizeof(struct uma_slab_refcnt) - \ 295 sizeof(struct uma_slab_head)) 296 297 struct uma_klink { 298 LIST_ENTRY(uma_klink) kl_link; 299 uma_keg_t kl_keg; 300 }; 301 typedef struct uma_klink *uma_klink_t; 302 303 /* 304 * Zone management structure 305 * 306 * TODO: Optimize for cache line size 307 * 308 */ 309 struct uma_zone { 310 const char *uz_name; /* Text name of the zone */ 311 struct mtx *uz_lock; /* Lock for the zone (keg's lock) */ 312 313 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 314 LIST_HEAD(,uma_bucket) uz_full_bucket; /* full buckets */ 315 LIST_HEAD(,uma_bucket) uz_free_bucket; /* Buckets for frees */ 316 317 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 318 struct uma_klink uz_klink; /* klink for first keg. */ 319 320 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 321 uma_ctor uz_ctor; /* Constructor for each allocation */ 322 uma_dtor uz_dtor; /* Destructor */ 323 uma_init uz_init; /* Initializer for each item */ 324 uma_fini uz_fini; /* Discards memory */ 325 326 uint32_t uz_flags; /* Flags inherited from kegs */ 327 uint32_t uz_size; /* Size inherited from kegs */ 328 329 uint64_t uz_allocs UMA_ALIGN; /* Total number of allocations */ 330 uint64_t uz_frees; /* Total number of frees */ 331 uint64_t uz_fails; /* Total number of alloc failures */ 332 uint64_t uz_sleeps; /* Total number of alloc sleeps */ 333 uint16_t uz_fills; /* Outstanding bucket fills */ 334 uint16_t uz_count; /* Highest amount of items in bucket */ 335 336 /* The next three fields are used to print a rate-limited warnings. */ 337 const char *uz_warning; /* Warning to print on failure */ 338 struct timeval uz_ratecheck; /* Warnings rate-limiting */ 339 340 /* 341 * This HAS to be the last item because we adjust the zone size 342 * based on NCPU and then allocate the space for the zones. 343 */ 344 struct uma_cache uz_cpu[1]; /* Per cpu caches */ 345 }; 346 347 /* 348 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 349 */ 350 #define UMA_ZFLAG_BUCKET 0x02000000 /* Bucket zone. */ 351 #define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 352 #define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 353 #define UMA_ZFLAG_PRIVALLOC 0x10000000 /* Use uz_allocf. */ 354 #define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 355 #define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 356 #define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 357 358 #define UMA_ZFLAG_INHERIT (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | \ 359 UMA_ZFLAG_BUCKET) 360 361 #undef UMA_ALIGN 362 363 #ifdef _KERNEL 364 /* Internal prototypes */ 365 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data); 366 void *uma_large_malloc(int size, int wait); 367 void uma_large_free(uma_slab_t slab); 368 369 /* Lock Macros */ 370 371 #define KEG_LOCK_INIT(k, lc) \ 372 do { \ 373 if ((lc)) \ 374 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 375 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 376 else \ 377 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 378 "UMA zone", MTX_DEF | MTX_DUPOK); \ 379 } while (0) 380 381 #define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 382 #define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 383 #define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 384 #define ZONE_LOCK(z) mtx_lock((z)->uz_lock) 385 #define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lock) 386 387 /* 388 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 389 * the slab structure. 390 * 391 * Arguments: 392 * hash The hash table to search. 393 * data The base page of the item. 394 * 395 * Returns: 396 * A pointer to a slab if successful, else NULL. 397 */ 398 static __inline uma_slab_t 399 hash_sfind(struct uma_hash *hash, uint8_t *data) 400 { 401 uma_slab_t slab; 402 int hval; 403 404 hval = UMA_HASH(hash, data); 405 406 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 407 if ((uint8_t *)slab->us_data == data) 408 return (slab); 409 } 410 return (NULL); 411 } 412 413 static __inline uma_slab_t 414 vtoslab(vm_offset_t va) 415 { 416 vm_page_t p; 417 uma_slab_t slab; 418 419 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 420 slab = (uma_slab_t )p->object; 421 422 if (p->flags & PG_SLAB) 423 return (slab); 424 else 425 return (NULL); 426 } 427 428 static __inline void 429 vsetslab(vm_offset_t va, uma_slab_t slab) 430 { 431 vm_page_t p; 432 433 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 434 p->object = (vm_object_t)slab; 435 p->flags |= PG_SLAB; 436 } 437 438 static __inline void 439 vsetobj(vm_offset_t va, vm_object_t obj) 440 { 441 vm_page_t p; 442 443 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 444 p->object = obj; 445 p->flags &= ~PG_SLAB; 446 } 447 448 /* 449 * The following two functions may be defined by architecture specific code 450 * if they can provide more effecient allocation functions. This is useful 451 * for using direct mapped addresses. 452 */ 453 void *uma_small_alloc(uma_zone_t zone, int bytes, uint8_t *pflag, int wait); 454 void uma_small_free(void *mem, int size, uint8_t flags); 455 #endif /* _KERNEL */ 456 457 #endif /* VM_UMA_INT_H */ 458