1 /*- 2 * Copyright (c) 2002-2005, 2009, 2013 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 bitmask. For item sizes that would yield more than 49 * 10% memory waste we potentially allocate a separate uma_slab_t if this will 50 * improve the number of items per slab that will fit. 51 * 52 * Other potential space optimizations are storing the 8bit of linkage in space 53 * wasted between items due to alignment problems. This may yield a much better 54 * memory footprint for certain sizes of objects. Another alternative is to 55 * increase the UMA_SLAB_SIZE, or allow for dynamic slab sizes. I prefer 56 * dynamic slab sizes because we could stick with 8 bit indices and only use 57 * large slab sizes for zones with a lot of waste per slab. This may create 58 * inefficiencies in the vm subsystem due to fragmentation in the address space. 59 * 60 * The only really gross cases, with regards to memory waste, are for those 61 * items that are just over half the page size. You can get nearly 50% waste, 62 * so you fall back to the memory footprint of the power of two allocator. I 63 * have looked at memory allocation sizes on many of the machines available to 64 * me, and there does not seem to be an abundance of allocations at this range 65 * so at this time it may not make sense to optimize for it. This can, of 66 * course, be solved with dynamic slab sizes. 67 * 68 * Kegs may serve multiple Zones but by far most of the time they only serve 69 * one. When a Zone is created, a Keg is allocated and setup for it. While 70 * the backing Keg stores slabs, the Zone caches Buckets of items allocated 71 * from the slabs. Each Zone is equipped with an init/fini and ctor/dtor 72 * pair, as well as with its own set of small per-CPU caches, layered above 73 * the Zone's general Bucket cache. 74 * 75 * The PCPU caches are protected by critical sections, and may be accessed 76 * safely only from their associated CPU, while the Zones backed by the same 77 * Keg all share a common Keg lock (to coalesce contention on the backing 78 * slabs). The backing Keg typically only serves one Zone but in the case of 79 * multiple Zones, one of the Zones is considered the Master Zone and all 80 * Zone-related stats from the Keg are done in the Master Zone. For an 81 * example of a Multi-Zone setup, refer to the Mbuf allocation code. 82 */ 83 84 /* 85 * This is the representation for normal (Non OFFPAGE slab) 86 * 87 * i == item 88 * s == slab pointer 89 * 90 * <---------------- Page (UMA_SLAB_SIZE) ------------------> 91 * ___________________________________________________________ 92 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ | 93 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header|| 94 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| 95 * |___________________________________________________________| 96 * 97 * 98 * This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE. 99 * 100 * ___________________________________________________________ 101 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ | 102 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| | 103 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| | 104 * |___________________________________________________________| 105 * ___________ ^ 106 * |slab header| | 107 * |___________|---* 108 * 109 */ 110 111 #ifndef VM_UMA_INT_H 112 #define VM_UMA_INT_H 113 114 #define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */ 115 #define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */ 116 #define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */ 117 118 #define UMA_BOOT_PAGES 64 /* Pages allocated for startup */ 119 120 /* Max waste percentage before going to off page slab management */ 121 #define UMA_MAX_WASTE 10 122 123 /* 124 * I doubt there will be many cases where this is exceeded. This is the initial 125 * size of the hash table for uma_slabs that are managed off page. This hash 126 * does expand by powers of two. Currently it doesn't get smaller. 127 */ 128 #define UMA_HASH_SIZE_INIT 32 129 130 /* 131 * I should investigate other hashing algorithms. This should yield a low 132 * number of collisions if the pages are relatively contiguous. 133 */ 134 135 #define UMA_HASH(h, s) ((((uintptr_t)s) >> UMA_SLAB_SHIFT) & (h)->uh_hashmask) 136 137 #define UMA_HASH_INSERT(h, s, mem) \ 138 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ 139 (mem))], (s), us_hlink) 140 #define UMA_HASH_REMOVE(h, s, mem) \ 141 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ 142 (mem))], (s), uma_slab, us_hlink) 143 144 /* Hash table for freed address -> slab translation */ 145 146 SLIST_HEAD(slabhead, uma_slab); 147 148 struct uma_hash { 149 struct slabhead *uh_slab_hash; /* Hash table for slabs */ 150 int uh_hashsize; /* Current size of the hash table */ 151 int uh_hashmask; /* Mask used during hashing */ 152 }; 153 154 /* 155 * align field or structure to cache line 156 */ 157 #if defined(__amd64__) 158 #define UMA_ALIGN __aligned(CACHE_LINE_SIZE) 159 #else 160 #define UMA_ALIGN 161 #endif 162 163 /* 164 * Structures for per cpu queues. 165 */ 166 167 struct uma_bucket { 168 LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ 169 int16_t ub_cnt; /* Count of free items. */ 170 int16_t ub_entries; /* Max items. */ 171 void *ub_bucket[]; /* actual allocation storage */ 172 }; 173 174 typedef struct uma_bucket * uma_bucket_t; 175 176 struct uma_cache { 177 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 178 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 179 uint64_t uc_allocs; /* Count of allocations */ 180 uint64_t uc_frees; /* Count of frees */ 181 } UMA_ALIGN; 182 183 typedef struct uma_cache * uma_cache_t; 184 185 /* 186 * Keg management structure 187 * 188 * TODO: Optimize for cache line size 189 * 190 */ 191 struct uma_keg { 192 struct mtx_padalign uk_lock; /* Lock for the keg */ 193 struct uma_hash uk_hash; 194 195 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 196 LIST_HEAD(,uma_slab) uk_part_slab; /* partially allocated slabs */ 197 LIST_HEAD(,uma_slab) uk_free_slab; /* empty slab list */ 198 LIST_HEAD(,uma_slab) uk_full_slab; /* full slabs */ 199 200 uint32_t uk_align; /* Alignment mask */ 201 uint32_t uk_pages; /* Total page count */ 202 uint32_t uk_free; /* Count of items free in slabs */ 203 uint32_t uk_size; /* Requested size of each item */ 204 uint32_t uk_rsize; /* Real size of each item */ 205 uint32_t uk_maxpages; /* Maximum number of pages to alloc */ 206 207 uma_init uk_init; /* Keg's init routine */ 208 uma_fini uk_fini; /* Keg's fini routine */ 209 uma_alloc uk_allocf; /* Allocation function */ 210 uma_free uk_freef; /* Free routine */ 211 212 u_long uk_offset; /* Next free offset from base KVA */ 213 vm_offset_t uk_kva; /* Zone base KVA */ 214 uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ 215 216 uint16_t uk_slabsize; /* Slab size for this keg */ 217 uint16_t uk_pgoff; /* Offset to uma_slab struct */ 218 uint16_t uk_ppera; /* pages per allocation from backend */ 219 uint16_t uk_ipers; /* Items per slab */ 220 uint32_t uk_flags; /* Internal flags */ 221 222 /* Least used fields go to the last cache line. */ 223 const char *uk_name; /* Name of creating zone. */ 224 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 225 }; 226 typedef struct uma_keg * uma_keg_t; 227 228 /* 229 * Free bits per-slab. 230 */ 231 #define SLAB_SETSIZE (PAGE_SIZE / UMA_SMALLEST_UNIT) 232 BITSET_DEFINE(slabbits, SLAB_SETSIZE); 233 234 /* 235 * The slab structure manages a single contiguous allocation from backing 236 * store and subdivides it into individually allocatable items. 237 */ 238 struct uma_slab { 239 uma_keg_t us_keg; /* Keg we live in */ 240 union { 241 LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ 242 unsigned long _us_size; /* Size of allocation */ 243 } us_type; 244 SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ 245 uint8_t *us_data; /* First item */ 246 struct slabbits us_free; /* Free bitmask. */ 247 #ifdef INVARIANTS 248 struct slabbits us_debugfree; /* Debug bitmask. */ 249 #endif 250 uint16_t us_freecount; /* How many are free? */ 251 uint8_t us_flags; /* Page flags see uma.h */ 252 uint8_t us_pad; /* Pad to 32bits, unused. */ 253 }; 254 255 #define us_link us_type._us_link 256 #define us_size us_type._us_size 257 258 /* 259 * The slab structure for UMA_ZONE_REFCNT zones for whose items we 260 * maintain reference counters in the slab for. 261 */ 262 struct uma_slab_refcnt { 263 struct uma_slab us_head; /* slab header data */ 264 uint32_t us_refcnt[0]; /* Actually larger. */ 265 }; 266 267 typedef struct uma_slab * uma_slab_t; 268 typedef struct uma_slab_refcnt * uma_slabrefcnt_t; 269 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int); 270 271 struct uma_klink { 272 LIST_ENTRY(uma_klink) kl_link; 273 uma_keg_t kl_keg; 274 }; 275 typedef struct uma_klink *uma_klink_t; 276 277 /* 278 * Zone management structure 279 * 280 * TODO: Optimize for cache line size 281 * 282 */ 283 struct uma_zone { 284 struct mtx_padalign uz_lock; /* Lock for the zone */ 285 struct mtx_padalign *uz_lockptr; 286 const char *uz_name; /* Text name of the zone */ 287 288 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 289 LIST_HEAD(,uma_bucket) uz_buckets; /* full buckets */ 290 291 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 292 struct uma_klink uz_klink; /* klink for first keg. */ 293 294 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 295 uma_ctor uz_ctor; /* Constructor for each allocation */ 296 uma_dtor uz_dtor; /* Destructor */ 297 uma_init uz_init; /* Initializer for each item */ 298 uma_fini uz_fini; /* Finalizer for each item. */ 299 uma_import uz_import; /* Import new memory to cache. */ 300 uma_release uz_release; /* Release memory from cache. */ 301 void *uz_arg; /* Import/release argument. */ 302 303 uint32_t uz_flags; /* Flags inherited from kegs */ 304 uint32_t uz_size; /* Size inherited from kegs */ 305 306 volatile u_long uz_allocs UMA_ALIGN; /* Total number of allocations */ 307 volatile u_long uz_fails; /* Total number of alloc failures */ 308 volatile u_long uz_frees; /* Total number of frees */ 309 uint64_t uz_sleeps; /* Total number of alloc sleeps */ 310 uint16_t uz_count; /* Highest amount of items in bucket */ 311 312 /* The next three fields are used to print a rate-limited warnings. */ 313 const char *uz_warning; /* Warning to print on failure */ 314 struct timeval uz_ratecheck; /* Warnings rate-limiting */ 315 316 /* 317 * This HAS to be the last item because we adjust the zone size 318 * based on NCPU and then allocate the space for the zones. 319 */ 320 struct uma_cache uz_cpu[1]; /* Per cpu caches */ 321 }; 322 323 /* 324 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 325 */ 326 #define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 327 #define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 328 #define UMA_ZFLAG_PRIVALLOC 0x10000000 /* Use uz_allocf. */ 329 #define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 330 #define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 331 #define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 332 333 #define UMA_ZFLAG_INHERIT (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY) 334 335 static inline uma_keg_t 336 zone_first_keg(uma_zone_t zone) 337 { 338 uma_klink_t klink; 339 340 klink = LIST_FIRST(&zone->uz_kegs); 341 return (klink != NULL) ? klink->kl_keg : NULL; 342 } 343 344 #undef UMA_ALIGN 345 346 #ifdef _KERNEL 347 /* Internal prototypes */ 348 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data); 349 void *uma_large_malloc(int size, int wait); 350 void uma_large_free(uma_slab_t slab); 351 352 /* Lock Macros */ 353 354 #define KEG_LOCK_INIT(k, lc) \ 355 do { \ 356 if ((lc)) \ 357 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 358 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 359 else \ 360 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 361 "UMA zone", MTX_DEF | MTX_DUPOK); \ 362 } while (0) 363 364 #define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 365 #define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 366 #define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 367 368 #define ZONE_LOCK_INIT(z, lc) \ 369 do { \ 370 if ((lc)) \ 371 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 372 (z)->uz_name, MTX_DEF | MTX_DUPOK); \ 373 else \ 374 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 375 "UMA zone", MTX_DEF | MTX_DUPOK); \ 376 } while (0) 377 378 #define ZONE_LOCK(z) mtx_lock((z)->uz_lockptr) 379 #define ZONE_TRYLOCK(z) mtx_trylock((z)->uz_lockptr) 380 #define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lockptr) 381 #define ZONE_LOCK_FINI(z) mtx_destroy(&(z)->uz_lock) 382 383 /* 384 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 385 * the slab structure. 386 * 387 * Arguments: 388 * hash The hash table to search. 389 * data The base page of the item. 390 * 391 * Returns: 392 * A pointer to a slab if successful, else NULL. 393 */ 394 static __inline uma_slab_t 395 hash_sfind(struct uma_hash *hash, uint8_t *data) 396 { 397 uma_slab_t slab; 398 int hval; 399 400 hval = UMA_HASH(hash, data); 401 402 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 403 if ((uint8_t *)slab->us_data == data) 404 return (slab); 405 } 406 return (NULL); 407 } 408 409 static __inline uma_slab_t 410 vtoslab(vm_offset_t va) 411 { 412 vm_page_t p; 413 uma_slab_t slab; 414 415 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 416 slab = (uma_slab_t )p->object; 417 418 if (p->flags & PG_SLAB) 419 return (slab); 420 else 421 return (NULL); 422 } 423 424 static __inline void 425 vsetslab(vm_offset_t va, uma_slab_t slab) 426 { 427 vm_page_t p; 428 429 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 430 p->object = (vm_object_t)slab; 431 p->flags |= PG_SLAB; 432 } 433 434 static __inline void 435 vsetobj(vm_offset_t va, vm_object_t obj) 436 { 437 vm_page_t p; 438 439 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 440 p->object = obj; 441 p->flags &= ~PG_SLAB; 442 } 443 444 /* 445 * The following two functions may be defined by architecture specific code 446 * if they can provide more effecient allocation functions. This is useful 447 * for using direct mapped addresses. 448 */ 449 void *uma_small_alloc(uma_zone_t zone, int bytes, uint8_t *pflag, int wait); 450 void uma_small_free(void *mem, int size, uint8_t flags); 451 #endif /* _KERNEL */ 452 453 #endif /* VM_UMA_INT_H */ 454