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/*
* Memory Pool implementation logic.
*/
#include "cache.h"
#include "mem-pool.h"
#define BLOCK_GROWTH_SIZE 1024*1024 - sizeof(struct mp_block);
/*
* Allocate a new mp_block and insert it after the block specified in
* `insert_after`. If `insert_after` is NULL, then insert block at the
* head of the linked list.
*/
static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool, size_t block_alloc, struct mp_block *insert_after)
{
struct mp_block *p;
mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
p->next_free = (char *)p->space;
p->end = p->next_free + block_alloc;
if (insert_after) {
p->next_block = insert_after->next_block;
insert_after->next_block = p;
} else {
p->next_block = mem_pool->mp_block;
mem_pool->mp_block = p;
}
return p;
}
void mem_pool_init(struct mem_pool **mem_pool, size_t initial_size)
{
struct mem_pool *pool;
if (*mem_pool)
return;
pool = xcalloc(1, sizeof(*pool));
pool->block_alloc = BLOCK_GROWTH_SIZE;
if (initial_size > 0)
mem_pool_alloc_block(pool, initial_size, NULL);
*mem_pool = pool;
}
void mem_pool_discard(struct mem_pool *mem_pool)
{
struct mp_block *block, *block_to_free;
while ((block = mem_pool->mp_block))
{
block_to_free = block;
block = block->next_block;
free(block_to_free);
}
free(mem_pool);
}
void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
{
struct mp_block *p = NULL;
void *r;
/* round up to a 'uintmax_t' alignment */
if (len & (sizeof(uintmax_t) - 1))
len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
if (mem_pool->mp_block &&
mem_pool->mp_block->end - mem_pool->mp_block->next_free >= len)
p = mem_pool->mp_block;
if (!p) {
if (len >= (mem_pool->block_alloc / 2))
return mem_pool_alloc_block(mem_pool, len, mem_pool->mp_block);
p = mem_pool_alloc_block(mem_pool, mem_pool->block_alloc, NULL);
}
r = p->next_free;
p->next_free += len;
return r;
}
void *mem_pool_calloc(struct mem_pool *mem_pool, size_t count, size_t size)
{
size_t len = st_mult(count, size);
void *r = mem_pool_alloc(mem_pool, len);
memset(r, 0, len);
return r;
}
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