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89 lines
3.6 KiB
C
89 lines
3.6 KiB
C
/* libunwind - a platform-independent unwind library
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Copyright (C) 2002-2003 Hewlett-Packard Co
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Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
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This file is part of libunwind.
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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#ifndef mempool_h
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#define mempool_h
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/* Memory pools provide simple memory management of fixed-size
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objects. Memory pools are used for two purposes:
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o To ensure a stack can be unwound even when a process
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is out of memory.
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o To ensure a stack can be unwound at any time in a
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multi-threaded process (e.g., even at a time when the normal
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malloc-lock is taken, possibly by the very thread that is
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being unwind).
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To achieve the second objective, memory pools allocate memory
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directly via mmap() system call (or an equivalent facility).
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The first objective is accomplished by reserving memory ahead of
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time. Since the memory requirements of stack unwinding generally
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depends on the complexity of the procedures being unwind, there is
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no absolute guarantee that unwinding will always work, but in
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practice, this should not be a serious problem. */
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#include <sys/types.h>
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#include "libunwind_i.h"
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#define sos_alloc(s) UNWI_ARCH_OBJ(_sos_alloc)(s)
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#define mempool_init(p,s,r) UNWI_ARCH_OBJ(_mempool_init)(p,s,r)
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#define mempool_alloc(p) UNWI_ARCH_OBJ(_mempool_alloc)(p)
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#define mempool_free(p,o) UNWI_ARCH_OBJ(_mempool_free)(p,o)
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/* The mempool structure should be treated as an opaque object. It's
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declared here only to enable static allocation of mempools. */
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struct mempool
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{
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pthread_mutex_t lock;
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size_t obj_size; /* object size (rounded up for alignment) */
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size_t chunk_size; /* allocation granularity */
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unsigned int reserve; /* minimum (desired) size of the free-list */
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unsigned int num_free; /* number of objects on the free-list */
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struct object
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{
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struct object *next;
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}
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*free_list;
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};
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/* Emergency allocation for one-time stuff that doesn't fit the memory
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pool model. A limited amount of memory is available in this
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fashion and once allocated, there is no way to free it. */
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extern void *sos_alloc (size_t size);
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/* Initialize POOL for an object size of OBJECT_SIZE bytes. RESERVE
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is the number of objects that should be reserved for use under
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tight memory situations. If it is zero, mempool attempts to pick a
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reasonable default value. */
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extern void mempool_init (struct mempool *pool,
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size_t obj_size, size_t reserve);
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extern void *mempool_alloc (struct mempool *pool);
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extern void mempool_free (struct mempool *pool, void *object);
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#endif /* mempool_h */
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