xref: /freebsd/sys/vm/uma.h (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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 visible 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  *	The initializer and the destructor should leave the object in the same
105  *	state.
106  */
107 typedef int (*uma_init)(void *mem, int size, int flags);
108 
109 /*
110  * Item discard function
111  *
112  * Arguments:
113  * 	item  A pointer to memory which has been 'freed' but has not left the
114  *	      zone's cache.
115  *	size  The size of the item being discarded.
116  *
117  * Returns:
118  *	Nothing
119  *
120  * Discussion:
121  *	This routine is called when memory leaves a zone and is returned to the
122  *	system for other uses.  It is the counter-part to the init function.
123  */
124 typedef void (*uma_fini)(void *mem, int size);
125 
126 /*
127  * What's the difference between initializing and constructing?
128  *
129  * The item is initialized when it is cached, and this is the state that the
130  * object should be in when returned to the allocator. The purpose of this is
131  * to remove some code which would otherwise be called on each allocation by
132  * utilizing a known, stable state.  This differs from the constructor which
133  * will be called on EVERY allocation.
134  *
135  * For example, in the initializer you may want to initialize embedded locks,
136  * NULL list pointers, set up initial states, magic numbers, etc.  This way if
137  * the object is held in the allocator and re-used it won't be necessary to
138  * re-initialize it.
139  *
140  * The constructor may be used to lock a data structure, link it on to lists,
141  * bump reference counts or total counts of outstanding structures, etc.
142  *
143  */
144 
145 
146 /* Function proto types */
147 
148 /*
149  * Create a new uma zone
150  *
151  * Arguments:
152  *	name  The text name of the zone for debugging and stats. This memory
153  *		should not be freed until the zone has been deallocated.
154  *	size  The size of the object that is being created.
155  *	ctor  The constructor that is called when the object is allocated.
156  *	dtor  The destructor that is called when the object is freed.
157  *	init  An initializer that sets up the initial state of the memory.
158  *	fini  A discard function that undoes initialization done by init.
159  *		ctor/dtor/init/fini may all be null, see notes above.
160  *	align A bitmask that corresponds to the requested alignment
161  *		eg 4 would be 0x3
162  *	flags A set of parameters that control the behavior of the zone.
163  *
164  * Returns:
165  *	A pointer to a structure which is intended to be opaque to users of
166  *	the interface.  The value may be null if the wait flag is not set.
167  */
168 uma_zone_t uma_zcreate(char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
169 			uma_init uminit, uma_fini fini, int align,
170 			u_int32_t flags);
171 
172 /*
173  * Create a secondary uma zone
174  *
175  * Arguments:
176  *	name  The text name of the zone for debugging and stats. This memory
177  *		should not be freed until the zone has been deallocated.
178  *	ctor  The constructor that is called when the object is allocated.
179  *	dtor  The destructor that is called when the object is freed.
180  *	zinit  An initializer that sets up the initial state of the memory
181  *		as the object passes from the Keg's slab to the Zone's cache.
182  *	zfini  A discard function that undoes initialization done by init
183  *		as the object passes from the Zone's cache to the Keg's slab.
184  *
185  *		ctor/dtor/zinit/zfini may all be null, see notes above.
186  *		Note that the zinit and zfini specified here are NOT
187  *		exactly the same as the init/fini specified to uma_zcreate()
188  *		when creating a master zone.  These zinit/zfini are called
189  *		on the TRANSITION from keg to zone (and vice-versa). Once
190  *		these are set, the primary zone may alter its init/fini
191  *		(which are called when the object passes from VM to keg)
192  *		using uma_zone_set_init/fini()) as well as its own
193  *		zinit/zfini (unset by default for master zone) with
194  *		uma_zone_set_zinit/zfini() (note subtle 'z' prefix).
195  *
196  *	master  A reference to this zone's Master Zone (Primary Zone),
197  *		which contains the backing Keg for the Secondary Zone
198  *		being added.
199  *
200  * Returns:
201  *	A pointer to a structure which is intended to be opaque to users of
202  *	the interface.  The value may be null if the wait flag is not set.
203  */
204 uma_zone_t uma_zsecond_create(char *name, uma_ctor ctor, uma_dtor dtor,
205 		    uma_init zinit, uma_fini zfini, uma_zone_t master);
206 
207 /*
208  * Add a second master to a secondary zone.  This provides multiple data
209  * backends for objects with the same size.  Both masters must have
210  * compatible allocation flags.  Presently, UMA_ZONE_MALLOC type zones are
211  * the only supported.
212  *
213  * Returns:
214  * 	Error on failure, 0 on success.
215  */
216 int uma_zsecond_add(uma_zone_t zone, uma_zone_t master);
217 
218 /*
219  * Definitions for uma_zcreate flags
220  *
221  * These flags share space with UMA_ZFLAGs in uma_int.h.  Be careful not to
222  * overlap when adding new features.  0xf0000000 is in use by uma_int.h.
223  */
224 #define UMA_ZONE_PAGEABLE	0x0001	/* Return items not fully backed by
225 					   physical memory XXX Not yet */
226 #define UMA_ZONE_ZINIT		0x0002	/* Initialize with zeros */
227 #define UMA_ZONE_STATIC		0x0004	/* Statically sized zone */
228 #define UMA_ZONE_OFFPAGE	0x0008	/* Force the slab structure allocation
229 					   off of the real memory */
230 #define UMA_ZONE_MALLOC		0x0010	/* For use by malloc(9) only! */
231 #define UMA_ZONE_NOFREE		0x0020	/* Do not free slabs of this type! */
232 #define UMA_ZONE_MTXCLASS	0x0040	/* Create a new lock class */
233 #define	UMA_ZONE_VM		0x0080	/*
234 					 * Used for internal vm datastructures
235 					 * only.
236 					 */
237 #define	UMA_ZONE_HASH		0x0100	/*
238 					 * Use a hash table instead of caching
239 					 * information in the vm_page.
240 					 */
241 #define	UMA_ZONE_SECONDARY	0x0200	/* Zone is a Secondary Zone */
242 #define	UMA_ZONE_REFCNT		0x0400	/* Allocate refcnts in slabs */
243 #define	UMA_ZONE_MAXBUCKET	0x0800	/* Use largest buckets */
244 #define	UMA_ZONE_CACHESPREAD	0x1000	/*
245 					 * Spread memory start locations across
246 					 * all possible cache lines.  May
247 					 * require many virtually contiguous
248 					 * backend pages and can fail early.
249 					 */
250 #define	UMA_ZONE_VTOSLAB	0x2000	/* Zone uses vtoslab for lookup. */
251 
252 /*
253  * These flags are shared between the keg and zone.  In zones wishing to add
254  * new kegs these flags must be compatible.  Some are determined based on
255  * physical parameters of the request and may not be provided by the consumer.
256  */
257 #define	UMA_ZONE_INHERIT						\
258     (UMA_ZONE_OFFPAGE | UMA_ZONE_MALLOC | UMA_ZONE_HASH |		\
259     UMA_ZONE_REFCNT | UMA_ZONE_VTOSLAB)
260 
261 /* Definitions for align */
262 #define UMA_ALIGN_PTR	(sizeof(void *) - 1)	/* Alignment fit for ptr */
263 #define UMA_ALIGN_LONG	(sizeof(long) - 1)	/* "" long */
264 #define UMA_ALIGN_INT	(sizeof(int) - 1)	/* "" int */
265 #define UMA_ALIGN_SHORT	(sizeof(short) - 1)	/* "" short */
266 #define UMA_ALIGN_CHAR	(sizeof(char) - 1)	/* "" char */
267 #define UMA_ALIGN_CACHE	(0 - 1)			/* Cache line size align */
268 
269 /*
270  * Destroys an empty uma zone.  If the zone is not empty uma complains loudly.
271  *
272  * Arguments:
273  *	zone  The zone we want to destroy.
274  *
275  */
276 void uma_zdestroy(uma_zone_t zone);
277 
278 /*
279  * Allocates an item out of a zone
280  *
281  * Arguments:
282  *	zone  The zone we are allocating from
283  *	arg   This data is passed to the ctor function
284  *	flags See sys/malloc.h for available flags.
285  *
286  * Returns:
287  *	A non-null pointer to an initialized element from the zone is
288  *	guaranteed if the wait flag is M_WAITOK.  Otherwise a null pointer
289  *	may be returned if the zone is empty or the ctor failed.
290  */
291 
292 void *uma_zalloc_arg(uma_zone_t zone, void *arg, int flags);
293 
294 /*
295  * Allocates an item out of a zone without supplying an argument
296  *
297  * This is just a wrapper for uma_zalloc_arg for convenience.
298  *
299  */
300 static __inline void *uma_zalloc(uma_zone_t zone, int flags);
301 
302 static __inline void *
303 uma_zalloc(uma_zone_t zone, int flags)
304 {
305 	return uma_zalloc_arg(zone, NULL, flags);
306 }
307 
308 /*
309  * Frees an item back into the specified zone.
310  *
311  * Arguments:
312  *	zone  The zone the item was originally allocated out of.
313  *	item  The memory to be freed.
314  *	arg   Argument passed to the destructor
315  *
316  * Returns:
317  *	Nothing.
318  */
319 
320 void uma_zfree_arg(uma_zone_t zone, void *item, void *arg);
321 
322 /*
323  * Frees an item back to a zone without supplying an argument
324  *
325  * This is just a wrapper for uma_zfree_arg for convenience.
326  *
327  */
328 static __inline void uma_zfree(uma_zone_t zone, void *item);
329 
330 static __inline void
331 uma_zfree(uma_zone_t zone, void *item)
332 {
333 	uma_zfree_arg(zone, item, NULL);
334 }
335 
336 /*
337  * XXX The rest of the prototypes in this header are h0h0 magic for the VM.
338  * If you think you need to use it for a normal zone you're probably incorrect.
339  */
340 
341 /*
342  * Backend page supplier routines
343  *
344  * Arguments:
345  *	zone  The zone that is requesting pages.
346  *	size  The number of bytes being requested.
347  *	pflag Flags for these memory pages, see below.
348  *	wait  Indicates our willingness to block.
349  *
350  * Returns:
351  *	A pointer to the allocated memory or NULL on failure.
352  */
353 
354 typedef void *(*uma_alloc)(uma_zone_t zone, int size, u_int8_t *pflag, int wait);
355 
356 /*
357  * Backend page free routines
358  *
359  * Arguments:
360  *	item  A pointer to the previously allocated pages.
361  *	size  The original size of the allocation.
362  *	pflag The flags for the slab.  See UMA_SLAB_* below.
363  *
364  * Returns:
365  *	None
366  */
367 typedef void (*uma_free)(void *item, int size, u_int8_t pflag);
368 
369 
370 
371 /*
372  * Sets up the uma allocator. (Called by vm_mem_init)
373  *
374  * Arguments:
375  *	bootmem  A pointer to memory used to bootstrap the system.
376  *
377  * Returns:
378  *	Nothing
379  *
380  * Discussion:
381  *	This memory is used for zones which allocate things before the
382  *	backend page supplier can give us pages.  It should be
383  *	UMA_SLAB_SIZE * boot_pages bytes. (see uma_int.h)
384  *
385  */
386 
387 void uma_startup(void *bootmem, int boot_pages);
388 
389 /*
390  * Finishes starting up the allocator.  This should
391  * be called when kva is ready for normal allocs.
392  *
393  * Arguments:
394  *	None
395  *
396  * Returns:
397  *	Nothing
398  *
399  * Discussion:
400  *	uma_startup2 is called by kmeminit() to enable us of uma for malloc.
401  */
402 
403 void uma_startup2(void);
404 
405 /*
406  * Reclaims unused memory for all zones
407  *
408  * Arguments:
409  *	None
410  * Returns:
411  *	None
412  *
413  * This should only be called by the page out daemon.
414  */
415 
416 void uma_reclaim(void);
417 
418 /*
419  * Sets the alignment mask to be used for all zones requesting cache
420  * alignment.  Should be called by MD boot code prior to starting VM/UMA.
421  *
422  * Arguments:
423  *	align The alignment mask
424  *
425  * Returns:
426  *	Nothing
427  */
428 void uma_set_align(int align);
429 
430 /*
431  * Switches the backing object of a zone
432  *
433  * Arguments:
434  *	zone  The zone to update.
435  *	obj   The VM object to use for future allocations.
436  *	size  The size of the object to allocate.
437  *
438  * Returns:
439  *	0  if kva space can not be allocated
440  *	1  if successful
441  *
442  * Discussion:
443  *	A NULL object can be used and uma will allocate one for you.  Setting
444  *	the size will limit the amount of memory allocated to this zone.
445  *
446  */
447 struct vm_object;
448 int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
449 
450 /*
451  * Sets a high limit on the number of items allowed in a zone
452  *
453  * Arguments:
454  *	zone  The zone to limit
455  *
456  * Returns:
457  *	Nothing
458  */
459 void uma_zone_set_max(uma_zone_t zone, int nitems);
460 
461 /*
462  * The following two routines (uma_zone_set_init/fini)
463  * are used to set the backend init/fini pair which acts on an
464  * object as it becomes allocated and is placed in a slab within
465  * the specified zone's backing keg.  These should probably not
466  * be changed once allocations have already begun, but only be set
467  * immediately upon zone creation.
468  */
469 void uma_zone_set_init(uma_zone_t zone, uma_init uminit);
470 void uma_zone_set_fini(uma_zone_t zone, uma_fini fini);
471 
472 /*
473  * The following two routines (uma_zone_set_zinit/zfini) are
474  * used to set the zinit/zfini pair which acts on an object as
475  * it passes from the backing Keg's slab cache to the
476  * specified Zone's bucket cache.  These should probably not
477  * be changed once allocations have already begun, but only be set
478  * immediately upon zone creation.
479  */
480 void uma_zone_set_zinit(uma_zone_t zone, uma_init zinit);
481 void uma_zone_set_zfini(uma_zone_t zone, uma_fini zfini);
482 
483 /*
484  * Replaces the standard page_alloc or obj_alloc functions for this zone
485  *
486  * Arguments:
487  *	zone   The zone whose backend allocator is being changed.
488  *	allocf A pointer to the allocation function
489  *
490  * Returns:
491  *	Nothing
492  *
493  * Discussion:
494  *	This could be used to implement pageable allocation, or perhaps
495  *	even DMA allocators if used in conjunction with the OFFPAGE
496  *	zone flag.
497  */
498 
499 void uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf);
500 
501 /*
502  * Used for freeing memory provided by the allocf above
503  *
504  * Arguments:
505  *	zone  The zone that intends to use this free routine.
506  *	freef The page freeing routine.
507  *
508  * Returns:
509  *	Nothing
510  */
511 
512 void uma_zone_set_freef(uma_zone_t zone, uma_free freef);
513 
514 /*
515  * These flags are setable in the allocf and visible in the freef.
516  */
517 #define UMA_SLAB_BOOT	0x01		/* Slab alloced from boot pages */
518 #define UMA_SLAB_KMEM	0x02		/* Slab alloced from kmem_map */
519 #define UMA_SLAB_KERNEL	0x04		/* Slab alloced from kernel_map */
520 #define UMA_SLAB_PRIV	0x08		/* Slab alloced from priv allocator */
521 #define UMA_SLAB_OFFP	0x10		/* Slab is managed separately  */
522 #define UMA_SLAB_MALLOC	0x20		/* Slab is a large malloc slab */
523 /* 0x40 and 0x80 are available */
524 
525 /*
526  * Used to pre-fill a zone with some number of items
527  *
528  * Arguments:
529  *	zone    The zone to fill
530  *	itemcnt The number of items to reserve
531  *
532  * Returns:
533  *	Nothing
534  *
535  * NOTE: This is blocking and should only be done at startup
536  */
537 void uma_prealloc(uma_zone_t zone, int itemcnt);
538 
539 /*
540  * Used to lookup the reference counter allocated for an item
541  * from a UMA_ZONE_REFCNT zone.  For UMA_ZONE_REFCNT zones,
542  * reference counters are allocated for items and stored in
543  * the underlying slab header.
544  *
545  * Arguments:
546  * 	zone  The UMA_ZONE_REFCNT zone to which the item belongs.
547  *	item  The address of the item for which we want a refcnt.
548  *
549  * Returns:
550  * 	A pointer to a u_int32_t reference counter.
551  */
552 u_int32_t *uma_find_refcnt(uma_zone_t zone, void *item);
553 
554 /*
555  * Used to determine if a fixed-size zone is exhausted.
556  *
557  * Arguments:
558  *	zone    The zone to check
559  *
560  * Returns:
561  * 	Non-zero if zone is exhausted.
562  */
563 int uma_zone_exhausted(uma_zone_t zone);
564 int uma_zone_exhausted_nolock(uma_zone_t zone);
565 
566 /*
567  * Exported statistics structures to be used by user space monitoring tools.
568  * Statistics stream consists of a uma_stream_header, followed by a series of
569  * alternative uma_type_header and uma_type_stat structures.
570  */
571 #define	UMA_STREAM_VERSION	0x00000001
572 struct uma_stream_header {
573 	u_int32_t	ush_version;	/* Stream format version. */
574 	u_int32_t	ush_maxcpus;	/* Value of MAXCPU for stream. */
575 	u_int32_t	ush_count;	/* Number of records. */
576 	u_int32_t	_ush_pad;	/* Pad/reserved field. */
577 };
578 
579 #define	UTH_MAX_NAME	32
580 #define	UTH_ZONE_SECONDARY	0x00000001
581 struct uma_type_header {
582 	/*
583 	 * Static per-zone data, some extracted from the supporting keg.
584 	 */
585 	char		uth_name[UTH_MAX_NAME];
586 	u_int32_t	uth_align;	/* Keg: alignment. */
587 	u_int32_t	uth_size;	/* Keg: requested size of item. */
588 	u_int32_t	uth_rsize;	/* Keg: real size of item. */
589 	u_int32_t	uth_maxpages;	/* Keg: maximum number of pages. */
590 	u_int32_t	uth_limit;	/* Keg: max items to allocate. */
591 
592 	/*
593 	 * Current dynamic zone/keg-derived statistics.
594 	 */
595 	u_int32_t	uth_pages;	/* Keg: pages allocated. */
596 	u_int32_t	uth_keg_free;	/* Keg: items free. */
597 	u_int32_t	uth_zone_free;	/* Zone: items free. */
598 	u_int32_t	uth_bucketsize;	/* Zone: desired bucket size. */
599 	u_int32_t	uth_zone_flags;	/* Zone: flags. */
600 	u_int64_t	uth_allocs;	/* Zone: number of allocations. */
601 	u_int64_t	uth_frees;	/* Zone: number of frees. */
602 	u_int64_t	uth_fails;	/* Zone: number of alloc failures. */
603 	u_int64_t	_uth_reserved1[3];	/* Reserved. */
604 };
605 
606 struct uma_percpu_stat {
607 	u_int64_t	ups_allocs;	/* Cache: number of allocations. */
608 	u_int64_t	ups_frees;	/* Cache: number of frees. */
609 	u_int64_t	ups_cache_free;	/* Cache: free items in cache. */
610 	u_int64_t	_ups_reserved[5];	/* Reserved. */
611 };
612 
613 #endif
614