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 * Actual size of uma_slab when it is placed at an end of a page 143 * with pointer sized alignment requirement. 144 */ 145 #define SIZEOF_UMA_SLAB ((sizeof(struct uma_slab) & UMA_ALIGN_PTR) ? \ 146 (sizeof(struct uma_slab) & ~UMA_ALIGN_PTR) + \ 147 (UMA_ALIGN_PTR + 1) : sizeof(struct uma_slab)) 148 149 /* 150 * Size of memory in a not offpage single page slab available for actual items. 151 */ 152 #define UMA_SLAB_SPACE (PAGE_SIZE - SIZEOF_UMA_SLAB) 153 154 /* 155 * I doubt there will be many cases where this is exceeded. This is the initial 156 * size of the hash table for uma_slabs that are managed off page. This hash 157 * does expand by powers of two. Currently it doesn't get smaller. 158 */ 159 #define UMA_HASH_SIZE_INIT 32 160 161 /* 162 * I should investigate other hashing algorithms. This should yield a low 163 * number of collisions if the pages are relatively contiguous. 164 */ 165 166 #define UMA_HASH(h, s) ((((uintptr_t)s) >> UMA_SLAB_SHIFT) & (h)->uh_hashmask) 167 168 #define UMA_HASH_INSERT(h, s, mem) \ 169 SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ 170 (mem))], (s), us_hlink) 171 #define UMA_HASH_REMOVE(h, s, mem) \ 172 SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ 173 (mem))], (s), uma_slab, us_hlink) 174 175 /* Hash table for freed address -> slab translation */ 176 177 SLIST_HEAD(slabhead, uma_slab); 178 179 struct uma_hash { 180 struct slabhead *uh_slab_hash; /* Hash table for slabs */ 181 int uh_hashsize; /* Current size of the hash table */ 182 int uh_hashmask; /* Mask used during hashing */ 183 }; 184 185 /* 186 * align field or structure to cache line 187 */ 188 #if defined(__amd64__) || defined(__powerpc64__) 189 #define UMA_ALIGN __aligned(128) 190 #else 191 #define UMA_ALIGN 192 #endif 193 194 /* 195 * Structures for per cpu queues. 196 */ 197 198 struct uma_bucket { 199 LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ 200 int16_t ub_cnt; /* Count of items in bucket. */ 201 int16_t ub_entries; /* Max items. */ 202 void *ub_bucket[]; /* actual allocation storage */ 203 }; 204 205 typedef struct uma_bucket * uma_bucket_t; 206 207 struct uma_cache { 208 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 209 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 210 uint64_t uc_allocs; /* Count of allocations */ 211 uint64_t uc_frees; /* Count of frees */ 212 } UMA_ALIGN; 213 214 typedef struct uma_cache * uma_cache_t; 215 216 /* 217 * Per-domain memory list. Embedded in the kegs. 218 */ 219 struct uma_domain { 220 LIST_HEAD(,uma_slab) ud_part_slab; /* partially allocated slabs */ 221 LIST_HEAD(,uma_slab) ud_free_slab; /* empty slab list */ 222 LIST_HEAD(,uma_slab) ud_full_slab; /* full slabs */ 223 }; 224 225 typedef struct uma_domain * uma_domain_t; 226 227 /* 228 * Keg management structure 229 * 230 * TODO: Optimize for cache line size 231 * 232 */ 233 struct uma_keg { 234 struct mtx uk_lock; /* Lock for the keg */ 235 struct uma_hash uk_hash; 236 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 237 238 struct domainset_ref uk_dr; /* Domain selection policy. */ 239 uint32_t uk_align; /* Alignment mask */ 240 uint32_t uk_pages; /* Total page count */ 241 uint32_t uk_free; /* Count of items free in slabs */ 242 uint32_t uk_reserve; /* Number of reserved items. */ 243 uint32_t uk_size; /* Requested size of each item */ 244 uint32_t uk_rsize; /* Real size of each item */ 245 uint32_t uk_maxpages; /* Maximum number of pages to alloc */ 246 247 uma_init uk_init; /* Keg's init routine */ 248 uma_fini uk_fini; /* Keg's fini routine */ 249 uma_alloc uk_allocf; /* Allocation function */ 250 uma_free uk_freef; /* Free routine */ 251 252 u_long uk_offset; /* Next free offset from base KVA */ 253 vm_offset_t uk_kva; /* Zone base KVA */ 254 uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ 255 256 uint32_t uk_pgoff; /* Offset to uma_slab struct */ 257 uint16_t uk_ppera; /* pages per allocation from backend */ 258 uint16_t uk_ipers; /* Items per slab */ 259 uint32_t uk_flags; /* Internal flags */ 260 261 /* Least used fields go to the last cache line. */ 262 const char *uk_name; /* Name of creating zone. */ 263 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 264 265 /* Must be last, variable sized. */ 266 struct uma_domain uk_domain[]; /* Keg's slab lists. */ 267 }; 268 typedef struct uma_keg * uma_keg_t; 269 270 /* 271 * Free bits per-slab. 272 */ 273 #define SLAB_SETSIZE (PAGE_SIZE / UMA_SMALLEST_UNIT) 274 BITSET_DEFINE(slabbits, SLAB_SETSIZE); 275 276 /* 277 * The slab structure manages a single contiguous allocation from backing 278 * store and subdivides it into individually allocatable items. 279 */ 280 struct uma_slab { 281 uma_keg_t us_keg; /* Keg we live in */ 282 union { 283 LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ 284 unsigned long _us_size; /* Size of allocation */ 285 } us_type; 286 SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ 287 uint8_t *us_data; /* First item */ 288 struct slabbits us_free; /* Free bitmask. */ 289 #ifdef INVARIANTS 290 struct slabbits us_debugfree; /* Debug bitmask. */ 291 #endif 292 uint16_t us_freecount; /* How many are free? */ 293 uint8_t us_flags; /* Page flags see uma.h */ 294 uint8_t us_domain; /* Backing NUMA domain. */ 295 }; 296 297 #define us_link us_type._us_link 298 #define us_size us_type._us_size 299 300 #if MAXMEMDOM >= 255 301 #error "Slab domain type insufficient" 302 #endif 303 304 typedef struct uma_slab * uma_slab_t; 305 typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int, int); 306 307 struct uma_klink { 308 LIST_ENTRY(uma_klink) kl_link; 309 uma_keg_t kl_keg; 310 }; 311 typedef struct uma_klink *uma_klink_t; 312 313 struct uma_zone_domain { 314 LIST_HEAD(,uma_bucket) uzd_buckets; /* full buckets */ 315 long uzd_nitems; /* total item count */ 316 long uzd_imax; /* maximum item count this period */ 317 long uzd_imin; /* minimum item count this period */ 318 long uzd_wss; /* working set size estimate */ 319 }; 320 321 typedef struct uma_zone_domain * uma_zone_domain_t; 322 323 /* 324 * Zone management structure 325 * 326 * TODO: Optimize for cache line size 327 * 328 */ 329 struct uma_zone { 330 /* Offset 0, used in alloc/free fast/medium fast path and const. */ 331 struct mtx *uz_lockptr; 332 const char *uz_name; /* Text name of the zone */ 333 struct uma_zone_domain *uz_domain; /* per-domain buckets */ 334 uint32_t uz_flags; /* Flags inherited from kegs */ 335 uint32_t uz_size; /* Size inherited from kegs */ 336 uma_ctor uz_ctor; /* Constructor for each allocation */ 337 uma_dtor uz_dtor; /* Destructor */ 338 uma_init uz_init; /* Initializer for each item */ 339 uma_fini uz_fini; /* Finalizer for each item. */ 340 341 /* Offset 64, used in bucket replenish. */ 342 uma_import uz_import; /* Import new memory to cache. */ 343 uma_release uz_release; /* Release memory from cache. */ 344 void *uz_arg; /* Import/release argument. */ 345 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 346 uint16_t uz_count; /* Amount of items in full bucket */ 347 uint16_t uz_count_min; /* Minimal amount of items there */ 348 /* 32bit pad on 64bit. */ 349 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 350 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 351 352 /* Offset 128 Rare. */ 353 /* 354 * The lock is placed here to avoid adjacent line prefetcher 355 * in fast paths and to take up space near infrequently accessed 356 * members to reduce alignment overhead. 357 */ 358 struct mtx uz_lock; /* Lock for the zone */ 359 struct uma_klink uz_klink; /* klink for first keg. */ 360 /* The next two fields are used to print a rate-limited warnings. */ 361 const char *uz_warning; /* Warning to print on failure */ 362 struct timeval uz_ratecheck; /* Warnings rate-limiting */ 363 struct task uz_maxaction; /* Task to run when at limit */ 364 365 /* 16 bytes of pad. */ 366 367 /* Offset 256, atomic stats. */ 368 volatile u_long uz_allocs UMA_ALIGN; /* Total number of allocations */ 369 volatile u_long uz_fails; /* Total number of alloc failures */ 370 volatile u_long uz_frees; /* Total number of frees */ 371 uint64_t uz_sleeps; /* Total number of alloc sleeps */ 372 373 /* 374 * This HAS to be the last item because we adjust the zone size 375 * based on NCPU and then allocate the space for the zones. 376 */ 377 struct uma_cache uz_cpu[]; /* Per cpu caches */ 378 379 /* uz_domain follows here. */ 380 }; 381 382 /* 383 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 384 */ 385 #define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 386 #define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 387 #define UMA_ZFLAG_BUCKET 0x10000000 /* Bucket zone. */ 388 #define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 389 #define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 390 #define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 391 392 #define UMA_ZFLAG_INHERIT \ 393 (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | UMA_ZFLAG_BUCKET) 394 395 static inline uma_keg_t 396 zone_first_keg(uma_zone_t zone) 397 { 398 uma_klink_t klink; 399 400 klink = LIST_FIRST(&zone->uz_kegs); 401 return (klink != NULL) ? klink->kl_keg : NULL; 402 } 403 404 #undef UMA_ALIGN 405 406 #ifdef _KERNEL 407 /* Internal prototypes */ 408 static __inline uma_slab_t hash_sfind(struct uma_hash *hash, uint8_t *data); 409 void *uma_large_malloc(vm_size_t size, int wait); 410 void *uma_large_malloc_domain(vm_size_t size, int domain, int wait); 411 void uma_large_free(uma_slab_t slab); 412 413 /* Lock Macros */ 414 415 #define KEG_LOCK_INIT(k, lc) \ 416 do { \ 417 if ((lc)) \ 418 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 419 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 420 else \ 421 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 422 "UMA zone", MTX_DEF | MTX_DUPOK); \ 423 } while (0) 424 425 #define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 426 #define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 427 #define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 428 429 #define ZONE_LOCK_INIT(z, lc) \ 430 do { \ 431 if ((lc)) \ 432 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 433 (z)->uz_name, MTX_DEF | MTX_DUPOK); \ 434 else \ 435 mtx_init(&(z)->uz_lock, (z)->uz_name, \ 436 "UMA zone", MTX_DEF | MTX_DUPOK); \ 437 } while (0) 438 439 #define ZONE_LOCK(z) mtx_lock((z)->uz_lockptr) 440 #define ZONE_TRYLOCK(z) mtx_trylock((z)->uz_lockptr) 441 #define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lockptr) 442 #define ZONE_LOCK_FINI(z) mtx_destroy(&(z)->uz_lock) 443 #define ZONE_LOCK_ASSERT(z) mtx_assert((z)->uz_lockptr, MA_OWNED) 444 445 /* 446 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 447 * the slab structure. 448 * 449 * Arguments: 450 * hash The hash table to search. 451 * data The base page of the item. 452 * 453 * Returns: 454 * A pointer to a slab if successful, else NULL. 455 */ 456 static __inline uma_slab_t 457 hash_sfind(struct uma_hash *hash, uint8_t *data) 458 { 459 uma_slab_t slab; 460 int hval; 461 462 hval = UMA_HASH(hash, data); 463 464 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 465 if ((uint8_t *)slab->us_data == data) 466 return (slab); 467 } 468 return (NULL); 469 } 470 471 static __inline uma_slab_t 472 vtoslab(vm_offset_t va) 473 { 474 vm_page_t p; 475 476 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 477 return ((uma_slab_t)p->plinks.s.pv); 478 } 479 480 static __inline void 481 vsetslab(vm_offset_t va, uma_slab_t slab) 482 { 483 vm_page_t p; 484 485 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 486 p->plinks.s.pv = slab; 487 } 488 489 /* 490 * The following two functions may be defined by architecture specific code 491 * if they can provide more efficient allocation functions. This is useful 492 * for using direct mapped addresses. 493 */ 494 void *uma_small_alloc(uma_zone_t zone, vm_size_t bytes, int domain, 495 uint8_t *pflag, int wait); 496 void uma_small_free(void *mem, vm_size_t size, uint8_t flags); 497 498 /* Set a global soft limit on UMA managed memory. */ 499 void uma_set_limit(unsigned long limit); 500 #endif /* _KERNEL */ 501 502 #endif /* VM_UMA_INT_H */ 503