mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-18 05:32:52 +00:00
90 lines
3.6 KiB
C++
90 lines
3.6 KiB
C++
/* 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 */
|