Viewing file:  palloc.h (4.84 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
* Copyright (c) 2013-2017 Phusion Holding B.V.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _PASSENGER_MEMORY_KIT_PALLOC_H_INCLUDED_
#define _PASSENGER_MEMORY_KIT_PALLOC_H_INCLUDED_
#include <stddef.h>
#include <stdint.h>
#include <StaticString.h>
/** A pool allocator taken from Nginx. Modified to suit our needs.
* The concept is also known as region-based memory management:
* http://en.wikipedia.org/wiki/Region-based_memory_management
*
* The allocator allocates small objects in a pool (region) by bumping
* a pointer, so allocating many small objects is extremely fast.
* Objects that don't fit inside the pool are handled by the
* "large memory allocator" and allocated directly using malloc().
* Except for objects allocated by the large memory allocator,
* objects can only be freed by freeing the entire pool.
*/
#define PSG_ALIGNMENT sizeof(unsigned long) /* platform word */
#define psg_align(d, a) (((d) + (a - 1)) & ~(a - 1))
#define psg_align_ptr(p, a) \
(char *) (((uintptr_t) (p) + ((uintptr_t) a - 1)) & ~((uintptr_t) a - 1))
/*
* PSG_MAX_ALLOC_FROM_POOL should be (psg_pagesize - 1), i.e. 4095 on x86.
* On Windows NT it decreases a number of locked pages in a kernel.
*/
#define psg_pagesize 4096
#define PSG_MAX_ALLOC_FROM_POOL (psg_pagesize - 1)
#define PSG_DEFAULT_POOL_SIZE (16 * 1024)
#define PSG_POOL_ALIGNMENT 16
#define PSG_MIN_POOL_SIZE \
psg_align((sizeof(psg_pool_t) + 2 * sizeof(psg_pool_large_t)), \
PSG_POOL_ALIGNMENT)
typedef struct psg_pool_s psg_pool_t;
typedef struct psg_pool_large_s psg_pool_large_t;
typedef struct psg_pool_large_s {
psg_pool_large_s *next;
void *alloc;
} psg_pool_large_t;
typedef struct {
char *last; /** Last allocated byte inside this block. */
char *end; /** End of block memory. Read-only */
psg_pool_t *next;
unsigned int failed;
} psg_pool_data_t;
struct psg_pool_s {
psg_pool_data_t data;
/*
* The following fields are only used for the first psg_pool_s,
* not for any subsequent psg_pool_s objects linked through
* `data.next`.
*/
size_t max; /* Read-only */
psg_pool_t *current;
psg_pool_large_t *large;
};
psg_pool_t *psg_create_pool(size_t size);
void psg_destroy_pool(psg_pool_t *pool);
bool psg_reset_pool(psg_pool_t *pool, size_t size);
/** Allocate `size` bytes from the pool, aligned on platform word size. */
void *psg_palloc(psg_pool_t *pool, size_t size);
/** Allocate `size` bytes from the pool, unaligned. **/
void *psg_pnalloc(psg_pool_t *pool, size_t size);
/** Allocate `size` bytes from the pool, unaligned. The allocated memory is zeroed. **/
void *psg_pcalloc(psg_pool_t *pool, size_t size);
/** Allocate `size` bytes from the pool, aligned on the given alignment. */
void *psg_pmemalign(psg_pool_t *pool, size_t size, size_t alignment);
/** Duplicate string by storing it inside the pool. Result is NULL terminated. */
Passenger::StaticString psg_pstrdup(psg_pool_t *pool, const Passenger::StaticString &str);
/** Attempt to free the given memory, which was allocated from the given pool.
* If the memory was allocated using the pool's large memory allocator,
* then the memory is freed. If not, then this function does nothing, because
* there is no way to free the memory without freeing the entire pool.
* Returns whether the memory was actually freed.
*/
bool psg_pfree(psg_pool_t *pool, void *p);
#endif /* _PASSENGER_MEMORY_KIT_PALLOC_H_INCLUDED_ */
|