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89 lines
3.6 KiB
89 lines
3.6 KiB
/* 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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