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