1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2002-2005, 2009, 2013 Jeffrey Roberson <jeff@FreeBSD.org> 5 * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice unmodified, this list of conditions, and the following 13 * disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 * 31 */ 32 33 #include <sys/_bitset.h> 34 #include <sys/_task.h> 35 36 /* 37 * This file includes definitions, structures, prototypes, and inlines that 38 * should not be used outside of the actual implementation of UMA. 39 */ 40 41 /* 42 * Here's a quick description of the relationship between the objects: 43 * 44 * Kegs contain lists of slabs which are stored in either the full bin, empty 45 * bin, or partially allocated bin, to reduce fragmentation. They also contain 46 * the user supplied value for size, which is adjusted for alignment purposes 47 * and rsize is the result of that. The Keg also stores information for 48 * managing a hash of page addresses that maps pages to uma_slab_t structures 49 * for pages that don't have embedded uma_slab_t's. 50 * 51 * The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may 52 * be allocated off the page from a special slab zone. The free list within a 53 * slab is managed with a bitmask. For item sizes that would yield more than 54 * 10% memory waste we potentially allocate a separate uma_slab_t if this will 55 * improve the number of items per slab that will fit. 56 * 57 * The only really gross cases, with regards to memory waste, are for those 58 * items that are just over half the page size. You can get nearly 50% waste, 59 * so you fall back to the memory footprint of the power of two allocator. I 60 * have looked at memory allocation sizes on many of the machines available to 61 * me, and there does not seem to be an abundance of allocations at this range 62 * so at this time it may not make sense to optimize for it. This can, of 63 * course, be solved with dynamic slab sizes. 64 * 65 * Kegs may serve multiple Zones but by far most of the time they only serve 66 * one. When a Zone is created, a Keg is allocated and setup for it. While 67 * the backing Keg stores slabs, the Zone caches Buckets of items allocated 68 * from the slabs. Each Zone is equipped with an init/fini and ctor/dtor 69 * pair, as well as with its own set of small per-CPU caches, layered above 70 * the Zone's general Bucket cache. 71 * 72 * The PCPU caches are protected by critical sections, and may be accessed 73 * safely only from their associated CPU, while the Zones backed by the same 74 * Keg all share a common Keg lock (to coalesce contention on the backing 75 * slabs). The backing Keg typically only serves one Zone but in the case of 76 * multiple Zones, one of the Zones is considered the Master Zone and all 77 * Zone-related stats from the Keg are done in the Master Zone. For an 78 * example of a Multi-Zone setup, refer to the Mbuf allocation code. 79 */ 80 81 /* 82 * This is the representation for normal (Non OFFPAGE slab) 83 * 84 * i == item 85 * s == slab pointer 86 * 87 * <---------------- Page (UMA_SLAB_SIZE) ------------------> 88 * ___________________________________________________________ 89 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ | 90 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header|| 91 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| 92 * |___________________________________________________________| 93 * 94 * 95 * This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE. 96 * 97 * ___________________________________________________________ 98 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ | 99 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| | 100 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| | 101 * |___________________________________________________________| 102 * ___________ ^ 103 * |slab header| | 104 * |___________|---* 105 * 106 */ 107 108 #ifndef VM_UMA_INT_H 109 #define VM_UMA_INT_H 110 111 #define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */ 112 #define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */ 113 #define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */ 114 115 #define UMA_BOOT_PAGES 64 /* Pages allocated for startup */ 116 #define UMA_BOOT_PAGES_ZONES 32 /* Multiplier for pages to reserve */ 117 /* if uma_zone > PAGE_SIZE */ 118 119 /* Max waste percentage before going to off page slab management */ 120 #define UMA_MAX_WASTE 10 121 122 /* 123 * I doubt there will be many cases where this is exceeded. This is the initial 124 * size of the hash table for uma_slabs that are managed off page. This hash 125 * does expand by powers of two. Currently it doesn't get smaller. 126 */ 127 #define UMA_HASH_SIZE_INIT 32 128 129 /* 130 * I should investigate other hashing algorithms. This should yield a low 131 * number of collisions if the pages are relatively contiguous. 132 */ 133 134 #define UMA_HASH(h, s) ((((uintptr_t)s) >> UMA_SLAB_SHIFT) & (h)->uh_hashmask) 135 136 #define UMA_HASH_INSERT(h, s, mem) \ 137 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ 138 (mem))], (s), us_hlink) 139 #define UMA_HASH_REMOVE(h, s, mem) \ 140 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ 141 (mem))], (s), uma_slab, us_hlink) 142 143 /* Hash table for freed address -> slab translation */ 144 145 SLIST_HEAD(slabhead, uma_slab); 146 147 struct uma_hash { 148 struct slabhead *uh_slab_hash; /* Hash table for slabs */ 149 int uh_hashsize; /* Current size of the hash table */ 150 int uh_hashmask; /* Mask used during hashing */ 151 }; 152 153 /* 154 * align field or structure to cache line 155 */ 156 #if defined(__amd64__) 157 #define UMA_ALIGN __aligned(CACHE_LINE_SIZE) 158 #else 159 #define UMA_ALIGN 160 #endif 161 162 /* 163 * Structures for per cpu queues. 164 */ 165 166 struct uma_bucket { 167 LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ 168 int16_t ub_cnt; /* Count of free items. */ 169 int16_t ub_entries; /* Max items. */ 170 void *ub_bucket[]; /* actual allocation storage */ 171 }; 172 173 typedef struct uma_bucket * uma_bucket_t; 174 175 struct uma_cache { 176 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 177 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 178 uint64_t uc_allocs; /* Count of allocations */ 179 uint64_t uc_frees; /* Count of frees */ 180 } UMA_ALIGN; 181 182 typedef struct uma_cache * uma_cache_t; 183 184 /* 185 * Keg management structure 186 * 187 * TODO: Optimize for cache line size 188 * 189 */ 190 struct uma_keg { 191 struct mtx_padalign uk_lock; /* Lock for the keg */ 192 struct uma_hash uk_hash; 193 194 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 195 LIST_HEAD(,uma_slab) uk_part_slab; /* partially allocated slabs */ 196 LIST_HEAD(,uma_slab) uk_free_slab; /* empty slab list */ 197 LIST_HEAD(,uma_slab) uk_full_slab; /* full slabs */ 198 199 uint32_t uk_align; /* Alignment mask */ 200 uint32_t uk_pages; /* Total page count */ 201 uint32_t uk_free; /* Count of items free in slabs */ 202 uint32_t uk_reserve; /* Number of reserved items. */ 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 uint32_t uk_pgoff; /* Offset to uma_slab struct */ 217 uint16_t uk_ppera; /* pages per allocation from backend */ 218 uint16_t uk_ipers; /* Items per slab */ 219 uint32_t uk_flags; /* Internal flags */ 220 221 /* Least used fields go to the last cache line. */ 222 const char *uk_name; /* Name of creating zone. */ 223 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 224 }; 225 typedef struct uma_keg * uma_keg_t; 226 227 /* 228 * Free bits per-slab. 229 */ 230 #define SLAB_SETSIZE (PAGE_SIZE / UMA_SMALLEST_UNIT) 231 BITSET_DEFINE(slabbits, SLAB_SETSIZE); 232 233 /* 234 * The slab structure manages a single contiguous allocation from backing 235 * store and subdivides it into individually allocatable items. 236 */ 237 struct uma_slab { 238 uma_keg_t us_keg; /* Keg we live in */ 239 union { 240 LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ 241 unsigned long _us_size; /* Size of allocation */ 242 } us_type; 243 SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ 244 uint8_t *us_data; /* First item */ 245 struct slabbits us_free; /* Free bitmask. */ 246 #ifdef INVARIANTS 247 struct slabbits us_debugfree; /* Debug bitmask. */ 248 #endif 249 uint16_t us_freecount; /* How many are free? */ 250 uint8_t us_flags; /* Page flags see uma.h */ 251 uint8_t us_pad; /* Pad to 32bits, unused. */ 252 }; 253 254 #define us_link us_type._us_link 255 #define us_size us_type._us_size 256 257 typedef struct uma_slab * uma_slab_t; 258 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int); 259 260 struct uma_klink { 261 LIST_ENTRY(uma_klink) kl_link; 262 uma_keg_t kl_keg; 263 }; 264 typedef struct uma_klink *uma_klink_t; 265 266 /* 267 * Zone management structure 268 * 269 * TODO: Optimize for cache line size 270 * 271 */ 272 struct uma_zone { 273 struct mtx_padalign uz_lock; /* Lock for the zone */ 274 struct mtx_padalign *uz_lockptr; 275 const char *uz_name; /* Text name of the zone */ 276 277 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 278 LIST_HEAD(,uma_bucket) uz_buckets; /* full buckets */ 279 280 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 281 struct uma_klink uz_klink; /* klink for first keg. */ 282 283 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 284 uma_ctor uz_ctor; /* Constructor for each allocation */ 285 uma_dtor uz_dtor; /* Destructor */ 286 uma_init uz_init; /* Initializer for each item */ 287 uma_fini uz_fini; /* Finalizer for each item. */ 288 uma_import uz_import; /* Import new memory to cache. */ 289 uma_release uz_release; /* Release memory from cache. */ 290 void *uz_arg; /* Import/release argument. */ 291 292 uint32_t uz_flags; /* Flags inherited from kegs */ 293 uint32_t uz_size; /* Size inherited from kegs */ 294 295 volatile u_long uz_allocs UMA_ALIGN; /* Total number of allocations */ 296 volatile u_long uz_fails; /* Total number of alloc failures */ 297 volatile u_long uz_frees; /* Total number of frees */ 298 uint64_t uz_sleeps; /* Total number of alloc sleeps */ 299 uint16_t uz_count; /* Amount of items in full bucket */ 300 uint16_t uz_count_min; /* Minimal amount of items there */ 301 302 /* The next two fields are used to print a rate-limited warnings. */ 303 const char *uz_warning; /* Warning to print on failure */ 304 struct timeval uz_ratecheck; /* Warnings rate-limiting */ 305 306 struct task uz_maxaction; /* Task to run when at limit */ 307 308 /* 309 * This HAS to be the last item because we adjust the zone size 310 * based on NCPU and then allocate the space for the zones. 311 */ 312 struct uma_cache uz_cpu[1]; /* Per cpu caches */ 313 }; 314 315 /* 316 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 317 */ 318 #define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 319 #define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 320 #define UMA_ZFLAG_BUCKET 0x10000000 /* Bucket zone. */ 321 #define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 322 #define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 323 #define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 324 325 #define UMA_ZFLAG_INHERIT \ 326 (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | UMA_ZFLAG_BUCKET) 327 328 static inline uma_keg_t 329 zone_first_keg(uma_zone_t zone) 330 { 331 uma_klink_t klink; 332 333 klink = LIST_FIRST(&zone->uz_kegs); 334 return (klink != NULL) ? klink->kl_keg : NULL; 335 } 336 337 #undef UMA_ALIGN 338 339 #ifdef _KERNEL 340 /* Internal prototypes */ 341 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data); 342 void *uma_large_malloc(vm_size_t size, int wait); 343 void uma_large_free(uma_slab_t slab); 344 345 /* Lock Macros */ 346 347 #define KEG_LOCK_INIT(k, lc) \ 348 do { \ 349 if ((lc)) \ 350 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 351 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 352 else \ 353 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 354 "UMA zone", MTX_DEF | MTX_DUPOK); \ 355 } while (0) 356 357 #define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 358 #define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 359 #define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 360 361 #define ZONE_LOCK_INIT(z, lc) \ 362 do { \ 363 if ((lc)) \ 364 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 365 (z)->uz_name, MTX_DEF | MTX_DUPOK); \ 366 else \ 367 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 368 "UMA zone", MTX_DEF | MTX_DUPOK); \ 369 } while (0) 370 371 #define ZONE_LOCK(z) mtx_lock((z)->uz_lockptr) 372 #define ZONE_TRYLOCK(z) mtx_trylock((z)->uz_lockptr) 373 #define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lockptr) 374 #define ZONE_LOCK_FINI(z) mtx_destroy(&(z)->uz_lock) 375 376 /* 377 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 378 * the slab structure. 379 * 380 * Arguments: 381 * hash The hash table to search. 382 * data The base page of the item. 383 * 384 * Returns: 385 * A pointer to a slab if successful, else NULL. 386 */ 387 static __inline uma_slab_t 388 hash_sfind(struct uma_hash *hash, uint8_t *data) 389 { 390 uma_slab_t slab; 391 int hval; 392 393 hval = UMA_HASH(hash, data); 394 395 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 396 if ((uint8_t *)slab->us_data == data) 397 return (slab); 398 } 399 return (NULL); 400 } 401 402 static __inline uma_slab_t 403 vtoslab(vm_offset_t va) 404 { 405 vm_page_t p; 406 407 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 408 return ((uma_slab_t)p->plinks.s.pv); 409 } 410 411 static __inline void 412 vsetslab(vm_offset_t va, uma_slab_t slab) 413 { 414 vm_page_t p; 415 416 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 417 p->plinks.s.pv = slab; 418 } 419 420 /* 421 * The following two functions may be defined by architecture specific code 422 * if they can provide more efficient allocation functions. This is useful 423 * for using direct mapped addresses. 424 */ 425 void *uma_small_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag, 426 int wait); 427 void uma_small_free(void *mem, vm_size_t size, uint8_t flags); 428 #endif /* _KERNEL */ 429 430 #endif /* VM_UMA_INT_H */ 431