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/_domainset.h> 35 #include <sys/_task.h> 36 37 /* 38 * This file includes definitions, structures, prototypes, and inlines that 39 * should not be used outside of the actual implementation of UMA. 40 */ 41 42 /* 43 * The brief summary; Zones describe unique allocation types. Zones are 44 * organized into per-CPU caches which are filled by buckets. Buckets are 45 * organized according to memory domains. Buckets are filled from kegs which 46 * are also organized according to memory domains. Kegs describe a unique 47 * allocation type, backend memory provider, and layout. Kegs are associated 48 * with one or more zones and zones reference one or more kegs. Kegs provide 49 * slabs which are virtually contiguous collections of pages. Each slab is 50 * broken down int one or more items that will satisfy an individual allocation. 51 * 52 * Allocation is satisfied in the following order: 53 * 1) Per-CPU cache 54 * 2) Per-domain cache of buckets 55 * 3) Slab from any of N kegs 56 * 4) Backend page provider 57 * 58 * More detail on individual objects is contained below: 59 * 60 * Kegs contain lists of slabs which are stored in either the full bin, empty 61 * bin, or partially allocated bin, to reduce fragmentation. They also contain 62 * the user supplied value for size, which is adjusted for alignment purposes 63 * and rsize is the result of that. The Keg also stores information for 64 * managing a hash of page addresses that maps pages to uma_slab_t structures 65 * for pages that don't have embedded uma_slab_t's. 66 * 67 * Keg slab lists are organized by memory domain to support NUMA allocation 68 * policies. By default allocations are spread across domains to reduce the 69 * potential for hotspots. Special keg creation flags may be specified to 70 * prefer location allocation. However there is no strict enforcement as frees 71 * may happen on any CPU and these are returned to the CPU-local cache 72 * regardless of the originating domain. 73 * 74 * The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may 75 * be allocated off the page from a special slab zone. The free list within a 76 * slab is managed with a bitmask. For item sizes that would yield more than 77 * 10% memory waste we potentially allocate a separate uma_slab_t if this will 78 * improve the number of items per slab that will fit. 79 * 80 * The only really gross cases, with regards to memory waste, are for those 81 * items that are just over half the page size. You can get nearly 50% waste, 82 * so you fall back to the memory footprint of the power of two allocator. I 83 * have looked at memory allocation sizes on many of the machines available to 84 * me, and there does not seem to be an abundance of allocations at this range 85 * so at this time it may not make sense to optimize for it. This can, of 86 * course, be solved with dynamic slab sizes. 87 * 88 * Kegs may serve multiple Zones but by far most of the time they only serve 89 * one. When a Zone is created, a Keg is allocated and setup for it. While 90 * the backing Keg stores slabs, the Zone caches Buckets of items allocated 91 * from the slabs. Each Zone is equipped with an init/fini and ctor/dtor 92 * pair, as well as with its own set of small per-CPU caches, layered above 93 * the Zone's general Bucket cache. 94 * 95 * The PCPU caches are protected by critical sections, and may be accessed 96 * safely only from their associated CPU, while the Zones backed by the same 97 * Keg all share a common Keg lock (to coalesce contention on the backing 98 * slabs). The backing Keg typically only serves one Zone but in the case of 99 * multiple Zones, one of the Zones is considered the Master Zone and all 100 * Zone-related stats from the Keg are done in the Master Zone. For an 101 * example of a Multi-Zone setup, refer to the Mbuf allocation code. 102 */ 103 104 /* 105 * This is the representation for normal (Non OFFPAGE slab) 106 * 107 * i == item 108 * s == slab pointer 109 * 110 * <---------------- Page (UMA_SLAB_SIZE) ------------------> 111 * ___________________________________________________________ 112 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ | 113 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header|| 114 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| 115 * |___________________________________________________________| 116 * 117 * 118 * This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE. 119 * 120 * ___________________________________________________________ 121 * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ | 122 * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| | 123 * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| | 124 * |___________________________________________________________| 125 * ___________ ^ 126 * |slab header| | 127 * |___________|---* 128 * 129 */ 130 131 #ifndef VM_UMA_INT_H 132 #define VM_UMA_INT_H 133 134 #define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */ 135 #define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */ 136 #define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */ 137 138 /* Max waste percentage before going to off page slab management */ 139 #define UMA_MAX_WASTE 10 140 141 /* 142 * Size of memory in a not offpage slab available for actual items. 143 */ 144 #define UMA_SLAB_SPACE (UMA_SLAB_SIZE - sizeof(struct uma_slab)) 145 146 /* 147 * I doubt there will be many cases where this is exceeded. This is the initial 148 * size of the hash table for uma_slabs that are managed off page. This hash 149 * does expand by powers of two. Currently it doesn't get smaller. 150 */ 151 #define UMA_HASH_SIZE_INIT 32 152 153 /* 154 * I should investigate other hashing algorithms. This should yield a low 155 * number of collisions if the pages are relatively contiguous. 156 */ 157 158 #define UMA_HASH(h, s) ((((uintptr_t)s) >> UMA_SLAB_SHIFT) & (h)->uh_hashmask) 159 160 #define UMA_HASH_INSERT(h, s, mem) \ 161 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ 162 (mem))], (s), us_hlink) 163 #define UMA_HASH_REMOVE(h, s, mem) \ 164 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ 165 (mem))], (s), uma_slab, us_hlink) 166 167 /* Hash table for freed address -> slab translation */ 168 169 SLIST_HEAD(slabhead, uma_slab); 170 171 struct uma_hash { 172 struct slabhead *uh_slab_hash; /* Hash table for slabs */ 173 int uh_hashsize; /* Current size of the hash table */ 174 int uh_hashmask; /* Mask used during hashing */ 175 }; 176 177 /* 178 * align field or structure to cache line 179 */ 180 #if defined(__amd64__) || defined(__powerpc64__) 181 #define UMA_ALIGN __aligned(128) 182 #else 183 #define UMA_ALIGN 184 #endif 185 186 /* 187 * Structures for per cpu queues. 188 */ 189 190 struct uma_bucket { 191 LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ 192 int16_t ub_cnt; /* Count of items in bucket. */ 193 int16_t ub_entries; /* Max items. */ 194 void *ub_bucket[]; /* actual allocation storage */ 195 }; 196 197 typedef struct uma_bucket * uma_bucket_t; 198 199 struct uma_cache { 200 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 201 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 202 uint64_t uc_allocs; /* Count of allocations */ 203 uint64_t uc_frees; /* Count of frees */ 204 } UMA_ALIGN; 205 206 typedef struct uma_cache * uma_cache_t; 207 208 /* 209 * Per-domain memory list. Embedded in the kegs. 210 */ 211 struct uma_domain { 212 LIST_HEAD(,uma_slab) ud_part_slab; /* partially allocated slabs */ 213 LIST_HEAD(,uma_slab) ud_free_slab; /* empty slab list */ 214 LIST_HEAD(,uma_slab) ud_full_slab; /* full slabs */ 215 }; 216 217 typedef struct uma_domain * uma_domain_t; 218 219 /* 220 * Keg management structure 221 * 222 * TODO: Optimize for cache line size 223 * 224 */ 225 struct uma_keg { 226 struct mtx uk_lock; /* Lock for the keg */ 227 struct uma_hash uk_hash; 228 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 229 230 struct domainset_ref uk_dr; /* Domain selection policy. */ 231 uint32_t uk_align; /* Alignment mask */ 232 uint32_t uk_pages; /* Total page count */ 233 uint32_t uk_free; /* Count of items free in slabs */ 234 uint32_t uk_reserve; /* Number of reserved items. */ 235 uint32_t uk_size; /* Requested size of each item */ 236 uint32_t uk_rsize; /* Real size of each item */ 237 uint32_t uk_maxpages; /* Maximum number of pages to alloc */ 238 239 uma_init uk_init; /* Keg's init routine */ 240 uma_fini uk_fini; /* Keg's fini routine */ 241 uma_alloc uk_allocf; /* Allocation function */ 242 uma_free uk_freef; /* Free routine */ 243 244 u_long uk_offset; /* Next free offset from base KVA */ 245 vm_offset_t uk_kva; /* Zone base KVA */ 246 uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ 247 248 uint32_t uk_pgoff; /* Offset to uma_slab struct */ 249 uint16_t uk_ppera; /* pages per allocation from backend */ 250 uint16_t uk_ipers; /* Items per slab */ 251 uint32_t uk_flags; /* Internal flags */ 252 253 /* Least used fields go to the last cache line. */ 254 const char *uk_name; /* Name of creating zone. */ 255 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 256 257 /* Must be last, variable sized. */ 258 struct uma_domain uk_domain[]; /* Keg's slab lists. */ 259 }; 260 typedef struct uma_keg * uma_keg_t; 261 262 /* 263 * Free bits per-slab. 264 */ 265 #define SLAB_SETSIZE (PAGE_SIZE / UMA_SMALLEST_UNIT) 266 BITSET_DEFINE(slabbits, SLAB_SETSIZE); 267 268 /* 269 * The slab structure manages a single contiguous allocation from backing 270 * store and subdivides it into individually allocatable items. 271 */ 272 struct uma_slab { 273 uma_keg_t us_keg; /* Keg we live in */ 274 union { 275 LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ 276 unsigned long _us_size; /* Size of allocation */ 277 } us_type; 278 SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ 279 uint8_t *us_data; /* First item */ 280 struct slabbits us_free; /* Free bitmask. */ 281 #ifdef INVARIANTS 282 struct slabbits us_debugfree; /* Debug bitmask. */ 283 #endif 284 uint16_t us_freecount; /* How many are free? */ 285 uint8_t us_flags; /* Page flags see uma.h */ 286 uint8_t us_domain; /* Backing NUMA domain. */ 287 }; 288 289 #define us_link us_type._us_link 290 #define us_size us_type._us_size 291 292 #if MAXMEMDOM >= 255 293 #error "Slab domain type insufficient" 294 #endif 295 296 typedef struct uma_slab * uma_slab_t; 297 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int, int); 298 299 struct uma_klink { 300 LIST_ENTRY(uma_klink) kl_link; 301 uma_keg_t kl_keg; 302 }; 303 typedef struct uma_klink *uma_klink_t; 304 305 struct uma_zone_domain { 306 LIST_HEAD(,uma_bucket) uzd_buckets; /* full buckets */ 307 long uzd_nitems; /* total item count */ 308 long uzd_imax; /* maximum item count this period */ 309 long uzd_imin; /* minimum item count this period */ 310 long uzd_wss; /* working set size estimate */ 311 }; 312 313 typedef struct uma_zone_domain * uma_zone_domain_t; 314 315 /* 316 * Zone management structure 317 * 318 * TODO: Optimize for cache line size 319 * 320 */ 321 struct uma_zone { 322 /* Offset 0, used in alloc/free fast/medium fast path and const. */ 323 struct mtx *uz_lockptr; 324 const char *uz_name; /* Text name of the zone */ 325 struct uma_zone_domain *uz_domain; /* per-domain buckets */ 326 uint32_t uz_flags; /* Flags inherited from kegs */ 327 uint32_t uz_size; /* Size inherited from kegs */ 328 uma_ctor uz_ctor; /* Constructor for each allocation */ 329 uma_dtor uz_dtor; /* Destructor */ 330 uma_init uz_init; /* Initializer for each item */ 331 uma_fini uz_fini; /* Finalizer for each item. */ 332 333 /* Offset 64, used in bucket replenish. */ 334 uma_import uz_import; /* Import new memory to cache. */ 335 uma_release uz_release; /* Release memory from cache. */ 336 void *uz_arg; /* Import/release argument. */ 337 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 338 uint16_t uz_count; /* Amount of items in full bucket */ 339 uint16_t uz_count_min; /* Minimal amount of items there */ 340 /* 32bit pad on 64bit. */ 341 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 342 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 343 344 /* Offset 128 Rare. */ 345 /* 346 * The lock is placed here to avoid adjacent line prefetcher 347 * in fast paths and to take up space near infrequently accessed 348 * members to reduce alignment overhead. 349 */ 350 struct mtx uz_lock; /* Lock for the zone */ 351 struct uma_klink uz_klink; /* klink for first keg. */ 352 /* The next two fields are used to print a rate-limited warnings. */ 353 const char *uz_warning; /* Warning to print on failure */ 354 struct timeval uz_ratecheck; /* Warnings rate-limiting */ 355 struct task uz_maxaction; /* Task to run when at limit */ 356 357 /* 16 bytes of pad. */ 358 359 /* Offset 256, atomic stats. */ 360 volatile u_long uz_allocs UMA_ALIGN; /* Total number of allocations */ 361 volatile u_long uz_fails; /* Total number of alloc failures */ 362 volatile u_long uz_frees; /* Total number of frees */ 363 uint64_t uz_sleeps; /* Total number of alloc sleeps */ 364 365 /* 366 * This HAS to be the last item because we adjust the zone size 367 * based on NCPU and then allocate the space for the zones. 368 */ 369 struct uma_cache uz_cpu[]; /* Per cpu caches */ 370 371 /* uz_domain follows here. */ 372 }; 373 374 /* 375 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 376 */ 377 #define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 378 #define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 379 #define UMA_ZFLAG_BUCKET 0x10000000 /* Bucket zone. */ 380 #define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 381 #define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 382 #define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 383 384 #define UMA_ZFLAG_INHERIT \ 385 (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | UMA_ZFLAG_BUCKET) 386 387 static inline uma_keg_t 388 zone_first_keg(uma_zone_t zone) 389 { 390 uma_klink_t klink; 391 392 klink = LIST_FIRST(&zone->uz_kegs); 393 return (klink != NULL) ? klink->kl_keg : NULL; 394 } 395 396 #undef UMA_ALIGN 397 398 #ifdef _KERNEL 399 /* Internal prototypes */ 400 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data); 401 void *uma_large_malloc(vm_size_t size, int wait); 402 void *uma_large_malloc_domain(vm_size_t size, int domain, int wait); 403 void uma_large_free(uma_slab_t slab); 404 405 /* Lock Macros */ 406 407 #define KEG_LOCK_INIT(k, lc) \ 408 do { \ 409 if ((lc)) \ 410 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 411 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 412 else \ 413 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 414 "UMA zone", MTX_DEF | MTX_DUPOK); \ 415 } while (0) 416 417 #define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 418 #define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 419 #define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 420 421 #define ZONE_LOCK_INIT(z, lc) \ 422 do { \ 423 if ((lc)) \ 424 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 425 (z)->uz_name, MTX_DEF | MTX_DUPOK); \ 426 else \ 427 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 428 "UMA zone", MTX_DEF | MTX_DUPOK); \ 429 } while (0) 430 431 #define ZONE_LOCK(z) mtx_lock((z)->uz_lockptr) 432 #define ZONE_TRYLOCK(z) mtx_trylock((z)->uz_lockptr) 433 #define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lockptr) 434 #define ZONE_LOCK_FINI(z) mtx_destroy(&(z)->uz_lock) 435 #define ZONE_LOCK_ASSERT(z) mtx_assert((z)->uz_lockptr, MA_OWNED) 436 437 /* 438 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 439 * the slab structure. 440 * 441 * Arguments: 442 * hash The hash table to search. 443 * data The base page of the item. 444 * 445 * Returns: 446 * A pointer to a slab if successful, else NULL. 447 */ 448 static __inline uma_slab_t 449 hash_sfind(struct uma_hash *hash, uint8_t *data) 450 { 451 uma_slab_t slab; 452 int hval; 453 454 hval = UMA_HASH(hash, data); 455 456 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 457 if ((uint8_t *)slab->us_data == data) 458 return (slab); 459 } 460 return (NULL); 461 } 462 463 static __inline uma_slab_t 464 vtoslab(vm_offset_t va) 465 { 466 vm_page_t p; 467 468 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 469 return ((uma_slab_t)p->plinks.s.pv); 470 } 471 472 static __inline void 473 vsetslab(vm_offset_t va, uma_slab_t slab) 474 { 475 vm_page_t p; 476 477 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 478 p->plinks.s.pv = slab; 479 } 480 481 /* 482 * The following two functions may be defined by architecture specific code 483 * if they can provide more efficient allocation functions. This is useful 484 * for using direct mapped addresses. 485 */ 486 void *uma_small_alloc(uma_zone_t zone, vm_size_t bytes, int domain, 487 uint8_t *pflag, int wait); 488 void uma_small_free(void *mem, vm_size_t size, uint8_t flags); 489 490 /* Set a global soft limit on UMA managed memory. */ 491 void uma_set_limit(unsigned long limit); 492 #endif /* _KERNEL */ 493 494 #endif /* VM_UMA_INT_H */ 495