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: head/sys/vm/uma_int.h 222163 2011-05-21 17:43:43Z alc $
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 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 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 */
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: head/sys/vm/uma_int.h 222163 2011-05-21 17:43:43Z alc $
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 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 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 */