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 before going to off page slab management */ 124#define UMA_MAX_WASTE (UMA_SLAB_SIZE / 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 154SLIST_HEAD(slabhead, uma_slab); 155 156struct 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 175struct 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 182typedef struct uma_bucket * uma_bucket_t; 183 184struct uma_cache { 185 uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ 186 uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ 187 u_int64_t uc_allocs; /* Count of allocations */ 188 u_int64_t uc_frees; /* Count of frees */ 189} UMA_ALIGN; 190 191typedef struct uma_cache * uma_cache_t; 192 193/* 194 * Keg management structure 195 * 196 * TODO: Optimize for cache line size 197 * 198 */ 199struct uma_keg { 200 LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ 201 202 struct mtx uk_lock; /* Lock for the keg */ 203 struct uma_hash uk_hash; 204 205 const char *uk_name; /* Name of creating zone. */ 206 LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ 207 LIST_HEAD(,uma_slab) uk_part_slab; /* partially allocated slabs */ 208 LIST_HEAD(,uma_slab) uk_free_slab; /* empty slab list */ 209 LIST_HEAD(,uma_slab) uk_full_slab; /* full slabs */ 210 211 u_int32_t uk_recurse; /* Allocation recursion count */ 212 u_int32_t uk_align; /* Alignment mask */ 213 u_int32_t uk_pages; /* Total page count */ 214 u_int32_t uk_free; /* Count of items free in slabs */ 215 u_int32_t uk_size; /* Requested size of each item */ 216 u_int32_t uk_rsize; /* Real size of each item */ 217 u_int32_t uk_maxpages; /* Maximum number of pages to alloc */ 218 219 uma_init uk_init; /* Keg's init routine */ 220 uma_fini uk_fini; /* Keg's fini routine */ 221 uma_alloc uk_allocf; /* Allocation function */ 222 uma_free uk_freef; /* Free routine */ 223 224 struct vm_object *uk_obj; /* Zone specific object */ 225 vm_offset_t uk_kva; /* Base kva for zones with objs */ 226 uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ 227 228 u_int16_t uk_pgoff; /* Offset to uma_slab struct */ 229 u_int16_t uk_ppera; /* pages per allocation from backend */ 230 u_int16_t uk_ipers; /* Items per slab */ 231 u_int32_t uk_flags; /* Internal flags */ 232}; 233typedef struct uma_keg * uma_keg_t; 234 235/* Page management structure */ 236 237/* Sorry for the union, but space efficiency is important */ 238struct uma_slab_head { 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 u_int8_t *us_data; /* First item */ 246 u_int8_t us_flags; /* Page flags see uma.h */ 247 u_int8_t us_freecount; /* How many are free? */ 248 u_int8_t us_firstfree; /* First free item index */ 249}; 250 251/* The standard slab structure */ 252struct uma_slab { 253 struct uma_slab_head us_head; /* slab header data */ 254 struct { 255 u_int8_t us_item; 256 } us_freelist[1]; /* actual number bigger */ 257}; 258 259/* 260 * The slab structure for UMA_ZONE_REFCNT zones for whose items we 261 * maintain reference counters in the slab for. 262 */ 263struct uma_slab_refcnt { 264 struct uma_slab_head us_head; /* slab header data */ 265 struct { 266 u_int8_t us_item; 267 u_int32_t us_refcnt; 268 } us_freelist[1]; /* actual number bigger */ 269}; 270 271#define us_keg us_head.us_keg 272#define us_link us_head.us_type._us_link 273#define us_size us_head.us_type._us_size 274#define us_hlink us_head.us_hlink 275#define us_data us_head.us_data 276#define us_flags us_head.us_flags 277#define us_freecount us_head.us_freecount 278#define us_firstfree us_head.us_firstfree 279 280typedef struct uma_slab * uma_slab_t; 281typedef struct uma_slab_refcnt * uma_slabrefcnt_t; 282typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int); 283 284 285/* 286 * These give us the size of one free item reference within our corresponding 287 * uma_slab structures, so that our calculations during zone setup are correct 288 * regardless of what the compiler decides to do with padding the structure 289 * arrays within uma_slab. 290 */ 291#define UMA_FRITM_SZ (sizeof(struct uma_slab) - sizeof(struct uma_slab_head)) 292#define UMA_FRITMREF_SZ (sizeof(struct uma_slab_refcnt) - \ 293 sizeof(struct uma_slab_head)) 294 295struct uma_klink { 296 LIST_ENTRY(uma_klink) kl_link; 297 uma_keg_t kl_keg; 298}; 299typedef struct uma_klink *uma_klink_t; 300 301/* 302 * Zone management structure 303 * 304 * TODO: Optimize for cache line size 305 * 306 */ 307struct uma_zone { 308 const char *uz_name; /* Text name of the zone */ 309 struct mtx *uz_lock; /* Lock for the zone (keg's lock) */ 310 311 LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ 312 LIST_HEAD(,uma_bucket) uz_full_bucket; /* full buckets */ 313 LIST_HEAD(,uma_bucket) uz_free_bucket; /* Buckets for frees */ 314 315 LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ 316 struct uma_klink uz_klink; /* klink for first keg. */ 317 318 uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ 319 uma_ctor uz_ctor; /* Constructor for each allocation */ 320 uma_dtor uz_dtor; /* Destructor */ 321 uma_init uz_init; /* Initializer for each item */ 322 uma_fini uz_fini; /* Discards memory */ 323 324 u_int32_t uz_flags; /* Flags inherited from kegs */ 325 u_int32_t uz_size; /* Size inherited from kegs */ 326 327 u_int64_t uz_allocs UMA_ALIGN; /* Total number of allocations */ 328 u_int64_t uz_frees; /* Total number of frees */ 329 u_int64_t uz_fails; /* Total number of alloc failures */ 330 u_int64_t uz_sleeps; /* Total number of alloc sleeps */ 331 uint16_t uz_fills; /* Outstanding bucket fills */ 332 uint16_t uz_count; /* Highest value ub_ptr can have */ 333 334 /* 335 * This HAS to be the last item because we adjust the zone size 336 * based on NCPU and then allocate the space for the zones. 337 */ 338 struct uma_cache uz_cpu[1]; /* Per cpu caches */ 339}; 340 341/* 342 * These flags must not overlap with the UMA_ZONE flags specified in uma.h. 343 */ 344#define UMA_ZFLAG_BUCKET 0x02000000 /* Bucket zone. */ 345#define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ 346#define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ 347#define UMA_ZFLAG_PRIVALLOC 0x10000000 /* Use uz_allocf. */ 348#define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ 349#define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ 350#define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ 351 352#define UMA_ZFLAG_INHERIT (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | \ 353 UMA_ZFLAG_BUCKET) 354 355#undef UMA_ALIGN 356 357#ifdef _KERNEL 358/* Internal prototypes */ 359static __inline uma_slab_t hash_sfind(struct uma_hash *hash, u_int8_t *data); 360void *uma_large_malloc(int size, int wait); 361void uma_large_free(uma_slab_t slab); 362 363/* Lock Macros */ 364 365#define KEG_LOCK_INIT(k, lc) \ 366 do { \ 367 if ((lc)) \ 368 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 369 (k)->uk_name, MTX_DEF | MTX_DUPOK); \ 370 else \ 371 mtx_init(&(k)->uk_lock, (k)->uk_name, \ 372 "UMA zone", MTX_DEF | MTX_DUPOK); \ 373 } while (0) 374 375#define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) 376#define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) 377#define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) 378#define ZONE_LOCK(z) mtx_lock((z)->uz_lock) 379#define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lock) 380 381/* 382 * Find a slab within a hash table. This is used for OFFPAGE zones to lookup 383 * the slab structure. 384 * 385 * Arguments: 386 * hash The hash table to search. 387 * data The base page of the item. 388 * 389 * Returns: 390 * A pointer to a slab if successful, else NULL. 391 */ 392static __inline uma_slab_t 393hash_sfind(struct uma_hash *hash, u_int8_t *data) 394{ 395 uma_slab_t slab; 396 int hval; 397 398 hval = UMA_HASH(hash, data); 399 400 SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { 401 if ((u_int8_t *)slab->us_data == data) 402 return (slab); 403 } 404 return (NULL); 405} 406 407static __inline uma_slab_t 408vtoslab(vm_offset_t va) 409{ 410 vm_page_t p; 411 uma_slab_t slab; 412 413 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 414 slab = (uma_slab_t )p->object; 415 416 if (p->flags & PG_SLAB) 417 return (slab); 418 else 419 return (NULL); 420} 421 422static __inline void 423vsetslab(vm_offset_t va, uma_slab_t slab) 424{ 425 vm_page_t p; 426 427 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 428 p->object = (vm_object_t)slab; 429 p->flags |= PG_SLAB; 430} 431 432static __inline void 433vsetobj(vm_offset_t va, vm_object_t obj) 434{ 435 vm_page_t p; 436 437 p = PHYS_TO_VM_PAGE(pmap_kextract(va)); 438 p->object = obj; 439 p->flags &= ~PG_SLAB; 440} 441 442/* 443 * The following two functions may be defined by architecture specific code 444 * if they can provide more effecient allocation functions. This is useful 445 * for using direct mapped addresses. 446 */ 447void *uma_small_alloc(uma_zone_t zone, int bytes, u_int8_t *pflag, int wait); 448void uma_small_free(void *mem, int size, u_int8_t flags); 449#endif /* _KERNEL */ 450 451#endif /* VM_UMA_INT_H */ 452