2 * Copyright (c) 2002, Jeffrey Roberson <jroberson@chesapeake.net>
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31 * uma.h - External definitions for the Universal Memory Allocator
33 * Jeff Roberson <jroberson@chesapeake.net>
39 #include <sys/param.h> /* For NULL */
40 #include <sys/malloc.h> /* For M_* */
42 /* User visable parameters */
43 #define UMA_SMALLEST_UNIT (PAGE_SIZE / 256) /* Smallest item allocated */
45 /* Types and type defs */
48 /* Opaque type used as a handle to the zone */
49 typedef struct uma_zone * uma_zone_t;
55 * item A pointer to the memory which has been allocated.
56 * arg The arg field passed to uma_zalloc_arg
57 * size The size of the allocated item
63 * The constructor is called just before the memory is returned
64 * to the user. It may block if neccisary.
66 typedef void (*uma_ctor)(void *mem, int size, void *arg);
72 * item A pointer to the memory which has been allocated.
73 * size The size of the item being destructed.
74 * arg Argument passed through uma_zfree_arg
80 * The destructor may perform operations that differ from those performed
81 * by the initializer, but it must leave the object in the same state.
82 * This IS type stable storage. This is called after EVERY zfree call.
84 typedef void (*uma_dtor)(void *mem, int size, void *arg);
90 * item A pointer to the memory which has been allocated.
91 * size The size of the item being initialized.
97 * The initializer is called when the memory is cached in the uma zone.
98 * this should be the same state that the destructor leaves the object in.
100 typedef void (*uma_init)(void *mem, int size);
103 * Item discard function
106 * item A pointer to memory which has been 'freed' but has not left the
108 * size The size of the item being discarded.
114 * This routine is called when memory leaves a zone and is returned to the
115 * system for other uses. It is the counter part to the init function.
117 typedef void (*uma_fini)(void *mem, int size);
120 * What's the difference between initializing and constructing?
122 * The item is initialized when it is cached, and this is the state that the
123 * object should be in when returned to the allocator. The purpose of this is
124 * to remove some code which would otherwise be called on each allocation by
125 * utilizing a known, stable state. This differs from the constructor which
126 * will be called on EVERY allocation.
128 * For example, in the initializer you may want to initialize embeded locks,
129 * NULL list pointers, set up initial states, magic numbers, etc. This way if
130 * the object is held in the allocator and re-used it won't be neccisary to
133 * The constructor may be used to lock a data structure, link it on to lists,
134 * bump reference counts or total counts of outstanding structures, etc.
139 /* Function proto types */
142 * Create a new uma zone
145 * name The text name of the zone for debugging and stats, this memory
146 * should not be freed until the zone has been deallocated.
147 * size The size of the object that is being created.
148 * ctor The constructor that is called when the object is allocated
149 * dtor The destructor that is called when the object is freed.
150 * init An initializer that sets up the initial state of the memory.
151 * fini A discard function that undoes initialization done by init.
152 * ctor/dtor/init/fini may all be null, see notes above.
153 * align A bitmask that corisponds to the requested alignment
155 * flags A set of parameters that control the behavior of the zone
158 * A pointer to a structure which is intended to be opaque to users of
159 * the interface. The value may be null if the wait flag is not set.
162 uma_zone_t uma_zcreate(char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
163 uma_init uminit, uma_fini fini, int align,
166 /* Definitions for uma_zcreate flags */
167 #define UMA_ZONE_PAGEABLE 0x0001 /* Return items not fully backed by
168 physical memory XXX Not yet */
169 #define UMA_ZONE_ZINIT 0x0002 /* Initialize with zeros */
170 #define UMA_ZONE_STATIC 0x0004 /* Staticly sized zone */
171 #define UMA_ZONE_OFFPAGE 0x0008 /* Force the slab structure allocation
172 off of the real memory */
173 #define UMA_ZONE_MALLOC 0x0010 /* For use by malloc(9) only! */
174 #define UMA_ZONE_NOFREE 0x0020 /* Do not free slabs of this type! */
175 #define UMA_ZONE_MTXCLASS 0x0040 /* Create a new lock class */
176 #define UMA_ZONE_VM 0x0080 /* Used for internal vm datastructures */
178 /* Definitions for align */
179 #define UMA_ALIGN_PTR (sizeof(void *) - 1) /* Alignment fit for ptr */
180 #define UMA_ALIGN_LONG (sizeof(long) - 1) /* "" long */
181 #define UMA_ALIGN_INT (sizeof(int) - 1) /* "" int */
182 #define UMA_ALIGN_SHORT (sizeof(short) - 1) /* "" short */
183 #define UMA_ALIGN_CHAR (sizeof(char) - 1) /* "" char */
184 #define UMA_ALIGN_CACHE (16 - 1) /* Cache line size align */
187 * Destroys an empty uma zone. If the zone is not empty uma complains loudly.
190 * zone The zone we want to destroy.
194 void uma_zdestroy(uma_zone_t zone);
197 * Allocates an item out of a zone
200 * zone The zone we are allocating from
201 * arg This data is passed to the ctor function
202 * flags See sys/malloc.h for available flags.
205 * A non null pointer to an initialized element from the zone is
206 * garanteed if the wait flag is M_WAITOK, otherwise a null pointer may be
207 * returned if the zone is empty or the ctor failed.
210 void *uma_zalloc_arg(uma_zone_t zone, void *arg, int flags);
213 * Allocates an item out of a zone without supplying an argument
215 * This is just a wrapper for uma_zalloc_arg for convenience.
218 static __inline void *uma_zalloc(uma_zone_t zone, int flags);
220 static __inline void *
221 uma_zalloc(uma_zone_t zone, int flags)
223 return uma_zalloc_arg(zone, NULL, flags);
227 * Frees an item back into the specified zone.
230 * zone The zone the item was originally allocated out of.
231 * item The memory to be freed.
232 * arg Argument passed to the destructor
238 void uma_zfree_arg(uma_zone_t zone, void *item, void *arg);
241 * Frees an item back to a zone without supplying an argument
243 * This is just a wrapper for uma_zfree_arg for convenience.
246 static __inline void uma_zfree(uma_zone_t zone, void *item);
249 uma_zfree(uma_zone_t zone, void *item)
251 uma_zfree_arg(zone, item, NULL);
255 * XXX The rest of the prototypes in this header are h0h0 magic for the VM.
256 * If you think you need to use it for a normal zone you're probably incorrect.
260 * Backend page supplier routines
263 * zone The zone that is requesting pages
264 * size The number of bytes being requested
265 * pflag Flags for these memory pages, see below.
266 * wait Indicates our willingness to block.
269 * A pointer to the alloced memory or NULL on failure.
272 typedef void *(*uma_alloc)(uma_zone_t zone, int size, u_int8_t *pflag, int wait);
275 * Backend page free routines
278 * item A pointer to the previously allocated pages
279 * size The original size of the allocation
280 * pflag The flags for the slab. See UMA_SLAB_* below
285 typedef void (*uma_free)(void *item, int size, u_int8_t pflag);
290 * Sets up the uma allocator. (Called by vm_mem_init)
293 * bootmem A pointer to memory used to bootstrap the system.
299 * This memory is used for zones which allocate things before the
300 * backend page supplier can give us pages. It should be
301 * UMA_SLAB_SIZE * UMA_BOOT_PAGES bytes. (see uma_int.h)
305 void uma_startup(void *bootmem);
308 * Finishes starting up the allocator. This should
309 * be called when kva is ready for normal allocs.
312 * hash An area of memory that will become the malloc hash
313 * elems The number of elements in this array
319 * uma_startup2 is called by kmeminit() to prepare the malloc
320 * hash bucket, and enable use of uma for malloc ops.
323 void uma_startup2(void *hash, u_long elems);
326 * Reclaims unused memory for all zones
333 * This should only be called by the page out daemon.
336 void uma_reclaim(void);
339 * Switches the backing object of a zone
342 * zone The zone to update
343 * obj The obj to use for future allocations
344 * size The size of the object to allocate
347 * 0 if kva space can not be allocated
351 * A NULL object can be used and uma will allocate one for you. Setting
352 * the size will limit the amount of memory allocated to this zone.
356 int uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int size);
359 * Sets a high limit on the number of items allowed in a zone
362 * zone The zone to limit
367 void uma_zone_set_max(uma_zone_t zone, int nitems);
370 * Replaces the standard page_alloc or obj_alloc functions for this zone
373 * zone The zone whos back end allocator is being changed.
374 * allocf A pointer to the allocation function
380 * This could be used to implement pageable allocation, or perhaps
381 * even DMA allocators if used in conjunction with the OFFPAGE
385 void uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf);
388 * Used for freeing memory provided by the allocf above
391 * zone The zone that intends to use this free routine.
392 * freef The page freeing routine.
398 void uma_zone_set_freef(uma_zone_t zone, uma_free freef);
401 * These flags are setable in the allocf and visable in the freef.
403 #define UMA_SLAB_BOOT 0x01 /* Slab alloced from boot pages */
404 #define UMA_SLAB_KMEM 0x02 /* Slab alloced from kmem_map */
405 #define UMA_SLAB_PRIV 0x08 /* Slab alloced from priv allocator */
406 #define UMA_SLAB_OFFP 0x10 /* Slab is managed separately */
407 #define UMA_SLAB_MALLOC 0x20 /* Slab is a large malloc slab */
408 /* 0x40 and 0x80 are available */
411 * Used to pre-fill a zone with some number of items
414 * zone The zone to fill
415 * itemcnt The number of items to reserve
420 * NOTE: This is blocking and should only be done at startup
422 void uma_prealloc(uma_zone_t zone, int itemcnt);