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| | /*
* Memory Pool implementation logic.
*/
#include "cache.h"
#include "mem-pool.h"
static struct mp_block *mem_pool_alloc_block(struct mem_pool *mem_pool)
{
struct mp_block *p;
mem_pool->pool_alloc += sizeof(struct mp_block) + mem_pool->block_alloc;
p = xmalloc(st_add(sizeof(struct mp_block), mem_pool->block_alloc));
p->next_block = mem_pool->mp_block;
p->next_free = (char *)p->space;
p->end = p->next_free + mem_pool->block_alloc;
mem_pool->mp_block = p;
return p;
}
/*
* Allocates a block of memory with a specific size and
* appends it to the memory pool's list of blocks.
*
* This function is used to allocate blocks with sizes
* different than the default "block_alloc" size for the mem_pool.
*
* There are two use cases:
* 1) The initial block allocation for a memory pool.
*
* 2) large" blocks of a specific size, where the entire memory block
* is going to be used. This means the block will not have any
* available memory for future allocations. The block is placed at
* the end of the list so that it will be the last block searched
* for available space.
*/
static struct mp_block *mem_pool_alloc_block_with_size(struct mem_pool *mem_pool, size_t block_alloc)
{
struct mp_block *p, *block;
mem_pool->pool_alloc += sizeof(struct mp_block) + block_alloc;
p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
block = mem_pool->mp_block;
if (block) {
while (block->next_block)
block = block->next_block;
block->next_block = p;
} else {
mem_pool->mp_block = p;
}
p->next_block = NULL;
p->next_free = (char *)p->space;
p->end = p->next_free + block_alloc;
return p;
}
void *mem_pool_alloc(struct mem_pool *mem_pool, size_t len)
{
struct mp_block *p;
void *r;
/* round up to a 'uintmax_t' alignment */
if (len & (sizeof(uintmax_t) - 1))
len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
p = mem_pool->mp_block;
/*
* In performance profiling, there was a minor perf benefit to
* check for available memory in the head block via the if
* statement, and only going through the loop when needed.
*/
if (p &&
(p->end - p->next_free < len)) {
for (p = p->next_block; p; p = p->next_block)
if (p->end - p->next_free >= len)
break;
}
if (!p) {
if (len >= (mem_pool->block_alloc / 2))
p = mem_pool_alloc_block_with_size(mem_pool, len);
else
p = mem_pool_alloc_block(mem_pool);
}
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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