xref: /freebsd/sys/vm/uma.h (revision 71fe318b852b8dfb3e799cb12ef184750f7f8eac)
1 /*
2  * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice unmodified, this list of conditions, and the following
10  *    disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  *
28  */
29 
30 /*
31  * uma.h - External definitions for the Universal Memory Allocator
32  *
33 */
34 
35 #ifndef VM_UMA_H
36 #define VM_UMA_H
37 
38 #include <sys/param.h>		/* For NULL */
39 #include <sys/malloc.h>		/* For M_* */
40 
41 /* User visable parameters */
42 #define UMA_SMALLEST_UNIT       (PAGE_SIZE / 256) /* Smallest item allocated */
43 
44 /* Types and type defs */
45 
46 struct uma_zone;
47 /* Opaque type used as a handle to the zone */
48 typedef struct uma_zone * uma_zone_t;
49 
50 /*
51  * Item constructor
52  *
53  * Arguments:
54  *	item  A pointer to the memory which has been allocated.
55  *	arg   The arg field passed to uma_zalloc_arg
56  *	size  The size of the allocated item
57  *
58  * Returns:
59  *	Nothing
60  *
61  * Discussion:
62  *	The constructor is called just before the memory is returned
63  *	to the user. It may block if necessary.
64  */
65 typedef void (*uma_ctor)(void *mem, int size, void *arg);
66 
67 /*
68  * Item destructor
69  *
70  * Arguments:
71  *	item  A pointer to the memory which has been allocated.
72  *	size  The size of the item being destructed.
73  *	arg   Argument passed through uma_zfree_arg
74  *
75  * Returns:
76  *	Nothing
77  *
78  * Discussion:
79  *	The destructor may perform operations that differ from those performed
80  *	by the initializer, but it must leave the object in the same state.
81  *	This IS type stable storage.  This is called after EVERY zfree call.
82  */
83 typedef void (*uma_dtor)(void *mem, int size, void *arg);
84 
85 /*
86  * Item initializer
87  *
88  * Arguments:
89  *	item  A pointer to the memory which has been allocated.
90  *	size  The size of the item being initialized.
91  *
92  * Returns:
93  *	Nothing
94  *
95  * Discussion:
96  *	The initializer is called when the memory is cached in the uma zone.
97  *	this should be the same state that the destructor leaves the object in.
98  */
99 typedef void (*uma_init)(void *mem, int size);
100 
101 /*
102  * Item discard function
103  *
104  * Arguments:
105  * 	item  A pointer to memory which has been 'freed' but has not left the
106  *	      zone's cache.
107  *	size  The size of the item being discarded.
108  *
109  * Returns:
110  *	Nothing
111  *
112  * Discussion:
113  *	This routine is called when memory leaves a zone and is returned to the
114  *	system for other uses.  It is the counter part to the init function.
115  */
116 typedef void (*uma_fini)(void *mem, int size);
117 
118 /*
119  * What's the difference between initializing and constructing?
120  *
121  * The item is initialized when it is cached, and this is the state that the
122  * object should be in when returned to the allocator. The purpose of this is
123  * to remove some code which would otherwise be called on each allocation by
124  * utilizing a known, stable state.  This differs from the constructor which
125  * will be called on EVERY allocation.
126  *
127  * For example, in the initializer you may want to initialize embeded locks,
128  * NULL list pointers, set up initial states, magic numbers, etc.  This way if
129  * the object is held in the allocator and re-used it won't be necessary to
130  * re-initialize it.
131  *
132  * The constructor may be used to lock a data structure, link it on to lists,
133  * bump reference counts or total counts of outstanding structures, etc.
134  *
135  */
136 
137 
138 /* Function proto types */
139 
140 /*
141  * Create a new uma zone
142  *
143  * Arguments:
144  *	name  The text name of the zone for debugging and stats, this memory
145  *		should not be freed until the zone has been deallocated.
146  *	size  The size of the object that is being created.
147  *	ctor  The constructor that is called when the object is allocated
148  *	dtor  The destructor that is called when the object is freed.
149  *	init  An initializer that sets up the initial state of the memory.
150  *	fini  A discard function that undoes initialization done by init.
151  *		ctor/dtor/init/fini may all be null, see notes above.
152  *	align A bitmask that corisponds to the requested alignment
153  *		eg 4 would be 0x3
154  *	flags A set of parameters that control the behavior of the zone
155  *
156  * Returns:
157  *	A pointer to a structure which is intended to be opaque to users of
158  *	the interface.  The value may be null if the wait flag is not set.
159  */
160 
161 uma_zone_t uma_zcreate(char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
162 			uma_init uminit, uma_fini fini, int align,
163 			u_int16_t flags);
164 
165 /* Definitions for uma_zcreate flags */
166 #define UMA_ZONE_PAGEABLE	0x0001	/* Return items not fully backed by
167 					   physical memory XXX Not yet */
168 #define UMA_ZONE_ZINIT		0x0002	/* Initialize with zeros */
169 #define UMA_ZONE_STATIC		0x0004	/* Staticly sized zone */
170 #define UMA_ZONE_OFFPAGE	0x0008	/* Force the slab structure allocation
171 					   off of the real memory */
172 #define UMA_ZONE_MALLOC		0x0010	/* For use by malloc(9) only! */
173 #define UMA_ZONE_NOFREE		0x0020	/* Do not free slabs of this type! */
174 #define UMA_ZONE_MTXCLASS	0x0040	/* Create a new lock class */
175 #define	UMA_ZONE_VM		0x0080	/*
176 					 * Used for internal vm datastructures
177 					 * only.
178 					 */
179 #define	UMA_ZONE_HASH		0x0100	/*
180 					 * Use a hash table instead of caching
181 					 * information in the vm_page.
182 					 */
183 
184 /* Definitions for align */
185 #define UMA_ALIGN_PTR	(sizeof(void *) - 1)	/* Alignment fit for ptr */
186 #define UMA_ALIGN_LONG	(sizeof(long) - 1)	/* "" long */
187 #define UMA_ALIGN_INT	(sizeof(int) - 1)	/* "" int */
188 #define UMA_ALIGN_SHORT	(sizeof(short) - 1)	/* "" short */
189 #define UMA_ALIGN_CHAR	(sizeof(char) - 1)	/* "" char */
190 #define UMA_ALIGN_CACHE	(16 - 1)		/* Cache line size align */
191 
192 /*
193  * Destroys an empty uma zone.  If the zone is not empty uma complains loudly.
194  *
195  * Arguments:
196  *	zone  The zone we want to destroy.
197  *
198  */
199 
200 void uma_zdestroy(uma_zone_t zone);
201 
202 /*
203  * Allocates an item out of a zone
204  *
205  * Arguments:
206  *	zone  The zone we are allocating from
207  *	arg   This data is passed to the ctor function
208  *	flags See sys/malloc.h for available flags.
209  *
210  * Returns:
211  *	A non null pointer to an initialized element from the zone is
212  *	garanteed if the wait flag is M_WAITOK, otherwise a null pointer may be
213  *	returned if the zone is empty or the ctor failed.
214  */
215 
216 void *uma_zalloc_arg(uma_zone_t zone, void *arg, int flags);
217 
218 /*
219  * Allocates an item out of a zone without supplying an argument
220  *
221  * This is just a wrapper for uma_zalloc_arg for convenience.
222  *
223  */
224 static __inline void *uma_zalloc(uma_zone_t zone, int flags);
225 
226 static __inline void *
227 uma_zalloc(uma_zone_t zone, int flags)
228 {
229 	return uma_zalloc_arg(zone, NULL, flags);
230 }
231 
232 /*
233  * Frees an item back into the specified zone.
234  *
235  * Arguments:
236  *	zone  The zone the item was originally allocated out of.
237  *	item  The memory to be freed.
238  *	arg   Argument passed to the destructor
239  *
240  * Returns:
241  *	Nothing.
242  */
243 
244 void uma_zfree_arg(uma_zone_t zone, void *item, void *arg);
245 
246 /*
247  * Frees an item back to a zone without supplying an argument
248  *
249  * This is just a wrapper for uma_zfree_arg for convenience.
250  *
251  */
252 static __inline void uma_zfree(uma_zone_t zone, void *item);
253 
254 static __inline void
255 uma_zfree(uma_zone_t zone, void *item)
256 {
257 	uma_zfree_arg(zone, item, NULL);
258 }
259 
260 /*
261  * XXX The rest of the prototypes in this header are h0h0 magic for the VM.
262  * If you think you need to use it for a normal zone you're probably incorrect.
263  */
264 
265 /*
266  * Backend page supplier routines
267  *
268  * Arguments:
269  *	zone  The zone that is requesting pages
270  *	size  The number of bytes being requested
271  *	pflag Flags for these memory pages, see below.
272  *	wait  Indicates our willingness to block.
273  *
274  * Returns:
275  *	A pointer to the alloced memory or NULL on failure.
276  */
277 
278 typedef void *(*uma_alloc)(uma_zone_t zone, int size, u_int8_t *pflag, int wait);
279 
280 /*
281  * Backend page free routines
282  *
283  * Arguments:
284  *	item  A pointer to the previously allocated pages
285  *	size  The original size of the allocation
286  *	pflag The flags for the slab.  See UMA_SLAB_* below
287  *
288  * Returns:
289  *	None
290  */
291 typedef void (*uma_free)(void *item, int size, u_int8_t pflag);
292 
293 
294 
295 /*
296  * Sets up the uma allocator. (Called by vm_mem_init)
297  *
298  * Arguments:
299  *	bootmem  A pointer to memory used to bootstrap the system.
300  *
301  * Returns:
302  *	Nothing
303  *
304  * Discussion:
305  *	This memory is used for zones which allocate things before the
306  *	backend page supplier can give us pages.  It should be
307  *	UMA_SLAB_SIZE * UMA_BOOT_PAGES bytes. (see uma_int.h)
308  *
309  */
310 
311 void uma_startup(void *bootmem);
312 
313 /*
314  * Finishes starting up the allocator.  This should
315  * be called when kva is ready for normal allocs.
316  *
317  * Arguments:
318  *	None
319  *
320  * Returns:
321  *	Nothing
322  *
323  * Discussion:
324  *	uma_startup2 is called by kmeminit() to enable us of uma for malloc.
325  */
326 
327 void uma_startup2(void);
328 
329 /*
330  * Reclaims unused memory for all zones
331  *
332  * Arguments:
333  *	None
334  * Returns:
335  *	None
336  *
337  * This should only be called by the page out daemon.
338  */
339 
340 void uma_reclaim(void);
341 
342 /*
343  * Switches the backing object of a zone
344  *
345  * Arguments:
346  *	zone  The zone to update
347  *	obj   The obj to use for future allocations
348  *	size  The size of the object to allocate
349  *
350  * Returns:
351  *	0  if kva space can not be allocated
352  *	1  if successful
353  *
354  * Discussion:
355  *	A NULL object can be used and uma will allocate one for you.  Setting
356  *	the size will limit the amount of memory allocated to this zone.
357  *
358  */
359 struct vm_object;
360 int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
361 
362 /*
363  * Sets a high limit on the number of items allowed in a zone
364  *
365  * Arguments:
366  *	zone  The zone to limit
367  *
368  * Returns:
369  *	Nothing
370  */
371 void uma_zone_set_max(uma_zone_t zone, int nitems);
372 
373 /*
374  * Replaces the standard page_alloc or obj_alloc functions for this zone
375  *
376  * Arguments:
377  *	zone   The zone whos back end allocator is being changed.
378  *	allocf A pointer to the allocation function
379  *
380  * Returns:
381  *	Nothing
382  *
383  * Discussion:
384  *	This could be used to implement pageable allocation, or perhaps
385  *	even DMA allocators if used in conjunction with the OFFPAGE
386  *	zone flag.
387  */
388 
389 void uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf);
390 
391 /*
392  * Used for freeing memory provided by the allocf above
393  *
394  * Arguments:
395  *	zone  The zone that intends to use this free routine.
396  *	freef The page freeing routine.
397  *
398  * Returns:
399  *	Nothing
400  */
401 
402 void uma_zone_set_freef(uma_zone_t zone, uma_free freef);
403 
404 /*
405  * These flags are setable in the allocf and visable in the freef.
406  */
407 #define UMA_SLAB_BOOT	0x01		/* Slab alloced from boot pages */
408 #define UMA_SLAB_KMEM	0x02		/* Slab alloced from kmem_map */
409 #define UMA_SLAB_PRIV	0x08		/* Slab alloced from priv allocator */
410 #define UMA_SLAB_OFFP	0x10		/* Slab is managed separately  */
411 #define UMA_SLAB_MALLOC	0x20		/* Slab is a large malloc slab */
412 /* 0x40 and 0x80 are available */
413 
414 /*
415  * Used to pre-fill a zone with some number of items
416  *
417  * Arguments:
418  *	zone    The zone to fill
419  *	itemcnt The number of items to reserve
420  *
421  * Returns:
422  *	Nothing
423  *
424  * NOTE: This is blocking and should only be done at startup
425  */
426 void uma_prealloc(uma_zone_t zone, int itemcnt);
427 
428 
429 #endif
430