FreeBSD/Linux Kernel Cross Reference
sys/vm/uma.h
1 /*-
2 * Copyright (c) 2002, 2003, 2004, 2005 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 * uma.h - External definitions for the Universal Memory Allocator
33 *
34 */
35
36 #ifndef VM_UMA_H
37 #define VM_UMA_H
38
39 #include <sys/param.h> /* For NULL */
40 #include <sys/malloc.h> /* For M_* */
41
42 /* User visable parameters */
43 #define UMA_SMALLEST_UNIT (PAGE_SIZE / 256) /* Smallest item allocated */
44
45 /* Types and type defs */
46
47 struct uma_zone;
48 /* Opaque type used as a handle to the zone */
49 typedef struct uma_zone * uma_zone_t;
50
51 void zone_drain(uma_zone_t);
52
53 /*
54 * Item constructor
55 *
56 * Arguments:
57 * item A pointer to the memory which has been allocated.
58 * arg The arg field passed to uma_zalloc_arg
59 * size The size of the allocated item
60 * flags See zalloc flags
61 *
62 * Returns:
63 * 0 on success
64 * errno on failure
65 *
66 * Discussion:
67 * The constructor is called just before the memory is returned
68 * to the user. It may block if necessary.
69 */
70 typedef int (*uma_ctor)(void *mem, int size, void *arg, int flags);
71
72 /*
73 * Item destructor
74 *
75 * Arguments:
76 * item A pointer to the memory which has been allocated.
77 * size The size of the item being destructed.
78 * arg Argument passed through uma_zfree_arg
79 *
80 * Returns:
81 * Nothing
82 *
83 * Discussion:
84 * The destructor may perform operations that differ from those performed
85 * by the initializer, but it must leave the object in the same state.
86 * This IS type stable storage. This is called after EVERY zfree call.
87 */
88 typedef void (*uma_dtor)(void *mem, int size, void *arg);
89
90 /*
91 * Item initializer
92 *
93 * Arguments:
94 * item A pointer to the memory which has been allocated.
95 * size The size of the item being initialized.
96 * flags See zalloc flags
97 *
98 * Returns:
99 * 0 on success
100 * errno on failure
101 *
102 * Discussion:
103 * The initializer is called when the memory is cached in the uma zone.
104 * this should be the same state that the destructor leaves the object in.
105 */
106 typedef int (*uma_init)(void *mem, int size, int flags);
107
108 /*
109 * Item discard function
110 *
111 * Arguments:
112 * item A pointer to memory which has been 'freed' but has not left the
113 * zone's cache.
114 * size The size of the item being discarded.
115 *
116 * Returns:
117 * Nothing
118 *
119 * Discussion:
120 * This routine is called when memory leaves a zone and is returned to the
121 * system for other uses. It is the counter part to the init function.
122 */
123 typedef void (*uma_fini)(void *mem, int size);
124
125 /*
126 * What's the difference between initializing and constructing?
127 *
128 * The item is initialized when it is cached, and this is the state that the
129 * object should be in when returned to the allocator. The purpose of this is
130 * to remove some code which would otherwise be called on each allocation by
131 * utilizing a known, stable state. This differs from the constructor which
132 * will be called on EVERY allocation.
133 *
134 * For example, in the initializer you may want to initialize embeded locks,
135 * NULL list pointers, set up initial states, magic numbers, etc. This way if
136 * the object is held in the allocator and re-used it won't be necessary to
137 * re-initialize it.
138 *
139 * The constructor may be used to lock a data structure, link it on to lists,
140 * bump reference counts or total counts of outstanding structures, etc.
141 *
142 */
143
144
145 /* Function proto types */
146
147 /*
148 * Create a new uma zone
149 *
150 * Arguments:
151 * name The text name of the zone for debugging and stats, this memory
152 * should not be freed until the zone has been deallocated.
153 * size The size of the object that is being created.
154 * ctor The constructor that is called when the object is allocated
155 * dtor The destructor that is called when the object is freed.
156 * init An initializer that sets up the initial state of the memory.
157 * fini A discard function that undoes initialization done by init.
158 * ctor/dtor/init/fini may all be null, see notes above.
159 * align A bitmask that corisponds to the requested alignment
160 * eg 4 would be 0x3
161 * flags A set of parameters that control the behavior of the zone
162 *
163 * Returns:
164 * A pointer to a structure which is intended to be opaque to users of
165 * the interface. The value may be null if the wait flag is not set.
166 */
167 uma_zone_t uma_zcreate(char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
168 uma_init uminit, uma_fini fini, int align,
169 u_int32_t flags);
170
171 /*
172 * Create a secondary uma zone
173 *
174 * Arguments:
175 * name The text name of the zone for debugging and stats, this memory
176 * should not be freed until the zone has been deallocated.
177 * ctor The constructor that is called when the object is allocated
178 * dtor The destructor that is called when the object is freed.
179 * zinit An initializer that sets up the initial state of the memory
180 * as the object passes from the Keg's slab to the Zone's cache.
181 * zfini A discard function that undoes initialization done by init
182 * as the object passes from the Zone's cache to the Keg's slab.
183 *
184 * ctor/dtor/zinit/zfini may all be null, see notes above.
185 * Note that the zinit and zfini specified here are NOT
186 * exactly the same as the init/fini specified to uma_zcreate()
187 * when creating a master zone. These zinit/zfini are called
188 * on the TRANSITION from keg to zone (and vice-versa). Once
189 * these are set, the primary zone may alter its init/fini
190 * (which are called when the object passes from VM to keg)
191 * using uma_zone_set_init/fini()) as well as its own
192 * zinit/zfini (unset by default for master zone) with
193 * uma_zone_set_zinit/zfini() (note subtle 'z' prefix).
194 *
195 * master A reference to this zone's Master Zone (Primary Zone),
196 * which contains the backing Keg for the Secondary Zone
197 * being added.
198 *
199 * Returns:
200 * A pointer to a structure which is intended to be opaque to users of
201 * the interface. The value may be null if the wait flag is not set.
202 */
203 uma_zone_t uma_zsecond_create(char *name, uma_ctor ctor, uma_dtor dtor,
204 uma_init zinit, uma_fini zfini, uma_zone_t master);
205
206 /*
207 * Definitions for uma_zcreate flags
208 *
209 * These flags share space with UMA_ZFLAGs in uma_int.h. Be careful not to
210 * overlap when adding new features. 0xf0000000 is in use by uma_int.h.
211 */
212 #define UMA_ZONE_PAGEABLE 0x0001 /* Return items not fully backed by
213 physical memory XXX Not yet */
214 #define UMA_ZONE_ZINIT 0x0002 /* Initialize with zeros */
215 #define UMA_ZONE_STATIC 0x0004 /* Staticly sized zone */
216 #define UMA_ZONE_OFFPAGE 0x0008 /* Force the slab structure allocation
217 off of the real memory */
218 #define UMA_ZONE_MALLOC 0x0010 /* For use by malloc(9) only! */
219 #define UMA_ZONE_NOFREE 0x0020 /* Do not free slabs of this type! */
220 #define UMA_ZONE_MTXCLASS 0x0040 /* Create a new lock class */
221 #define UMA_ZONE_VM 0x0080 /*
222 * Used for internal vm datastructures
223 * only.
224 */
225 #define UMA_ZONE_HASH 0x0100 /*
226 * Use a hash table instead of caching
227 * information in the vm_page.
228 */
229 #define UMA_ZONE_SECONDARY 0x0200 /* Zone is a Secondary Zone */
230 #define UMA_ZONE_REFCNT 0x0400 /* Allocate refcnts in slabs */
231 #define UMA_ZONE_MAXBUCKET 0x0800 /* Use largest buckets */
232
233 /* Definitions for align */
234 #define UMA_ALIGN_PTR (sizeof(void *) - 1) /* Alignment fit for ptr */
235 #define UMA_ALIGN_LONG (sizeof(long) - 1) /* "" long */
236 #define UMA_ALIGN_INT (sizeof(int) - 1) /* "" int */
237 #define UMA_ALIGN_SHORT (sizeof(short) - 1) /* "" short */
238 #define UMA_ALIGN_CHAR (sizeof(char) - 1) /* "" char */
239 #define UMA_ALIGN_CACHE (16 - 1) /* Cache line size align */
240
241 /*
242 * Destroys an empty uma zone. If the zone is not empty uma complains loudly.
243 *
244 * Arguments:
245 * zone The zone we want to destroy.
246 *
247 */
248 void uma_zdestroy(uma_zone_t zone);
249
250 /*
251 * Allocates an item out of a zone
252 *
253 * Arguments:
254 * zone The zone we are allocating from
255 * arg This data is passed to the ctor function
256 * flags See sys/malloc.h for available flags.
257 *
258 * Returns:
259 * A non null pointer to an initialized element from the zone is
260 * garanteed if the wait flag is M_WAITOK, otherwise a null pointer may be
261 * returned if the zone is empty or the ctor failed.
262 */
263
264 void *uma_zalloc_arg(uma_zone_t zone, void *arg, int flags);
265
266 /*
267 * Allocates an item out of a zone without supplying an argument
268 *
269 * This is just a wrapper for uma_zalloc_arg for convenience.
270 *
271 */
272 static __inline void *uma_zalloc(uma_zone_t zone, int flags);
273
274 static __inline void *
275 uma_zalloc(uma_zone_t zone, int flags)
276 {
277 return uma_zalloc_arg(zone, NULL, flags);
278 }
279
280 /*
281 * Frees an item back into the specified zone.
282 *
283 * Arguments:
284 * zone The zone the item was originally allocated out of.
285 * item The memory to be freed.
286 * arg Argument passed to the destructor
287 *
288 * Returns:
289 * Nothing.
290 */
291
292 void uma_zfree_arg(uma_zone_t zone, void *item, void *arg);
293
294 /*
295 * Frees an item back to a zone without supplying an argument
296 *
297 * This is just a wrapper for uma_zfree_arg for convenience.
298 *
299 */
300 static __inline void uma_zfree(uma_zone_t zone, void *item);
301
302 static __inline void
303 uma_zfree(uma_zone_t zone, void *item)
304 {
305 uma_zfree_arg(zone, item, NULL);
306 }
307
308 /*
309 * XXX The rest of the prototypes in this header are h0h0 magic for the VM.
310 * If you think you need to use it for a normal zone you're probably incorrect.
311 */
312
313 /*
314 * Backend page supplier routines
315 *
316 * Arguments:
317 * zone The zone that is requesting pages
318 * size The number of bytes being requested
319 * pflag Flags for these memory pages, see below.
320 * wait Indicates our willingness to block.
321 *
322 * Returns:
323 * A pointer to the alloced memory or NULL on failure.
324 */
325
326 typedef void *(*uma_alloc)(uma_zone_t zone, int size, u_int8_t *pflag, int wait);
327
328 /*
329 * Backend page free routines
330 *
331 * Arguments:
332 * item A pointer to the previously allocated pages
333 * size The original size of the allocation
334 * pflag The flags for the slab. See UMA_SLAB_* below
335 *
336 * Returns:
337 * None
338 */
339 typedef void (*uma_free)(void *item, int size, u_int8_t pflag);
340
341
342
343 /*
344 * Sets up the uma allocator. (Called by vm_mem_init)
345 *
346 * Arguments:
347 * bootmem A pointer to memory used to bootstrap the system.
348 *
349 * Returns:
350 * Nothing
351 *
352 * Discussion:
353 * This memory is used for zones which allocate things before the
354 * backend page supplier can give us pages. It should be
355 * UMA_SLAB_SIZE * boot_pages bytes. (see uma_int.h)
356 *
357 */
358
359 void uma_startup(void *bootmem, int boot_pages);
360
361 /*
362 * Finishes starting up the allocator. This should
363 * be called when kva is ready for normal allocs.
364 *
365 * Arguments:
366 * None
367 *
368 * Returns:
369 * Nothing
370 *
371 * Discussion:
372 * uma_startup2 is called by kmeminit() to enable us of uma for malloc.
373 */
374
375 void uma_startup2(void);
376
377 /*
378 * Reclaims unused memory for all zones
379 *
380 * Arguments:
381 * None
382 * Returns:
383 * None
384 *
385 * This should only be called by the page out daemon.
386 */
387
388 void uma_reclaim(void);
389
390 /*
391 * Switches the backing object of a zone
392 *
393 * Arguments:
394 * zone The zone to update
395 * obj The obj to use for future allocations
396 * size The size of the object to allocate
397 *
398 * Returns:
399 * 0 if kva space can not be allocated
400 * 1 if successful
401 *
402 * Discussion:
403 * A NULL object can be used and uma will allocate one for you. Setting
404 * the size will limit the amount of memory allocated to this zone.
405 *
406 */
407 struct vm_object;
408 int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
409
410 /*
411 * Sets a high limit on the number of items allowed in a zone
412 *
413 * Arguments:
414 * zone The zone to limit
415 *
416 * Returns:
417 * Nothing
418 */
419 void uma_zone_set_max(uma_zone_t zone, int nitems);
420
421 /*
422 * The following two routines (uma_zone_set_init/fini)
423 * are used to set the backend init/fini pair which acts on an
424 * object as it becomes allocated and is placed in a slab within
425 * the specified zone's backing keg. These should probably not
426 * be changed once allocations have already begun and only
427 * immediately upon zone creation.
428 */
429 void uma_zone_set_init(uma_zone_t zone, uma_init uminit);
430 void uma_zone_set_fini(uma_zone_t zone, uma_fini fini);
431
432 /*
433 * The following two routines (uma_zone_set_zinit/zfini) are
434 * used to set the zinit/zfini pair which acts on an object as
435 * it passes from the backing Keg's slab cache to the
436 * specified Zone's bucket cache. These should probably not
437 * be changed once allocations have already begun and
438 * only immediately upon zone creation.
439 */
440 void uma_zone_set_zinit(uma_zone_t zone, uma_init zinit);
441 void uma_zone_set_zfini(uma_zone_t zone, uma_fini zfini);
442
443 /*
444 * Replaces the standard page_alloc or obj_alloc functions for this zone
445 *
446 * Arguments:
447 * zone The zone whos back end allocator is being changed.
448 * allocf A pointer to the allocation function
449 *
450 * Returns:
451 * Nothing
452 *
453 * Discussion:
454 * This could be used to implement pageable allocation, or perhaps
455 * even DMA allocators if used in conjunction with the OFFPAGE
456 * zone flag.
457 */
458
459 void uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf);
460
461 /*
462 * Used for freeing memory provided by the allocf above
463 *
464 * Arguments:
465 * zone The zone that intends to use this free routine.
466 * freef The page freeing routine.
467 *
468 * Returns:
469 * Nothing
470 */
471
472 void uma_zone_set_freef(uma_zone_t zone, uma_free freef);
473
474 /*
475 * These flags are setable in the allocf and visable in the freef.
476 */
477 #define UMA_SLAB_BOOT 0x01 /* Slab alloced from boot pages */
478 #define UMA_SLAB_KMEM 0x02 /* Slab alloced from kmem_map */
479 #define UMA_SLAB_PRIV 0x08 /* Slab alloced from priv allocator */
480 #define UMA_SLAB_OFFP 0x10 /* Slab is managed separately */
481 #define UMA_SLAB_MALLOC 0x20 /* Slab is a large malloc slab */
482 /* 0x40 and 0x80 are available */
483
484 /*
485 * Used to pre-fill a zone with some number of items
486 *
487 * Arguments:
488 * zone The zone to fill
489 * itemcnt The number of items to reserve
490 *
491 * Returns:
492 * Nothing
493 *
494 * NOTE: This is blocking and should only be done at startup
495 */
496 void uma_prealloc(uma_zone_t zone, int itemcnt);
497
498 /*
499 * Used to lookup the reference counter allocated for an item
500 * from a UMA_ZONE_REFCNT zone. For UMA_ZONE_REFCNT zones,
501 * reference counters are allocated for items and stored in
502 * the underlying slab header.
503 *
504 * Arguments:
505 * zone The UMA_ZONE_REFCNT zone to which the item belongs.
506 * item The address of the item for which we want a refcnt.
507 *
508 * Returns:
509 * A pointer to a u_int32_t reference counter.
510 */
511 u_int32_t *uma_find_refcnt(uma_zone_t zone, void *item);
512
513 /*
514 * Used to determine if a fixed-size zone is exhausted.
515 *
516 * Arguments:
517 * zone The zone to check
518 *
519 * Returns:
520 * Non-zero if zone is exhausted.
521 */
522 int uma_zone_exhausted(uma_zone_t zone);
523 int uma_zone_exhausted_nolock(uma_zone_t zone);
524
525 /*
526 * Exported statistics structures to be used by user space monitoring tools.
527 * Statistics stream consusts of a uma_stream_header, followed by a series of
528 * alternative uma_type_header and uma_type_stat structures. Statistics
529 * structures
530 */
531 #define UMA_STREAM_VERSION 0x00000001
532 struct uma_stream_header {
533 u_int32_t ush_version; /* Stream format version. */
534 u_int32_t ush_maxcpus; /* Value of MAXCPU for stream. */
535 u_int32_t ush_count; /* Number of records. */
536 u_int32_t _ush_pad; /* Pad/reserved field. */
537 };
538
539 #define UTH_MAX_NAME 32
540 #define UTH_ZONE_SECONDARY 0x00000001
541 struct uma_type_header {
542 /*
543 * Static per-zone data, some extracted from the supporting keg.
544 */
545 char uth_name[UTH_MAX_NAME];
546 u_int32_t uth_align; /* Keg: alignment. */
547 u_int32_t uth_size; /* Keg: requested size of item. */
548 u_int32_t uth_rsize; /* Keg: real size of item. */
549 u_int32_t uth_maxpages; /* Keg: maximum number of pages. */
550 u_int32_t uth_limit; /* Keg: max items to allocate. */
551
552 /*
553 * Current dynamic zone/keg-derived statistics.
554 */
555 u_int32_t uth_pages; /* Keg: pages allocated. */
556 u_int32_t uth_keg_free; /* Keg: items free. */
557 u_int32_t uth_zone_free; /* Zone: items free. */
558 u_int32_t uth_bucketsize; /* Zone: desired bucket size. */
559 u_int32_t uth_zone_flags; /* Zone: flags. */
560 u_int64_t uth_allocs; /* Zone: number of allocations. */
561 u_int64_t uth_frees; /* Zone: number of frees. */
562 u_int64_t uth_fails; /* Zone: number of alloc failures. */
563 u_int64_t _uth_reserved1[3]; /* Reserved. */
564 };
565
566 struct uma_percpu_stat {
567 u_int64_t ups_allocs; /* Cache: number of alloctions. */
568 u_int64_t ups_frees; /* Cache: number of frees. */
569 u_int64_t ups_cache_free; /* Cache: free items in cache. */
570 u_int64_t _ups_reserved[5]; /* Reserved. */
571 };
572
573 #endif
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